WorldWideScience

Sample records for hydrochloric acid leaching

  1. Quantitative leaching of a Nigerian iron ore in hydrochloric acid ...

    African Journals Online (AJOL)

    A study on the quantitative leaching of iron ore in hydrochloric acid solution has been undertaken. The elemental composition of the iron ore was also carried out using ICP-MS technique. The major elements in the iron ore include: Fe(66.7%); Al (0.2%); Si (5.2%); Ti (0.02%) and O (28.0%). Some traces of V, Ni, Zn, Ce, Cr, ...

  2. Copper Recovery from Roasted Chalcopyrite Concentrate by Using Hydrochloric Acid or Water Leaching Method

    OpenAIRE

    Bahar, Nurdan

    2015-01-01

    In this study, the sulphation roasting in atmospheric medium of chalcopyrite concentrate and hydrochloric acid or water leaching of roasted chalcopyrite concentrate were investigated. The effects of roasting temperature (200-700 oC) and roasting time (15-120 min.) on recovery of copper were also researched. The optimum roasting temperature and roasting time were determined to be 450 oC and 60 min., respectively. The roasted chalcopyrite concentrate is leached with hydrochloric acid solution o...

  3. Kinetics of Hydrochloric Acid Leaching of Titanium from Titanium-Bearing Electric Furnace Slag

    Science.gov (United States)

    Zheng, Fuqiang; Chen, Feng; Guo, Yufeng; Jiang, Tao; Travyanov, Andrew Yakovlevich; Qiu, Guanzhou

    2016-05-01

    The hydrochloric acid leaching of titanium from titanium-bearing electric furnace slag was investigated under different experimental conditions. The results indicate that particle size, hydrochloric acid concentration and reaction temperature were of significance to the leaching kinetics. Specifically, reaction temperature was the most important factor followed by hydrochloric acid concentration and particle size. The shrinking core model was used to describe the leaching process which was controlled by surface chemical reaction. The kinetic equation was obtained and the activation energy was found to be 43.16 kJ/mol. Iron and calcium species were almost completely dissolved in the acid when the extraction degree of titanium reached 99.84%. MgO (19.34 wt.%) and Al2O3 (32.45 wt.%) in the spinel were still in the leaching residue and SiO2 (43.53 wt.%) in the form of quartz remained in the leaching residue.

  4. Kinetic Aspects of Leaching Zinc from Waste Galvanizing Zinc by Using Hydrochloric Acid Solutions

    Science.gov (United States)

    Sminčáková, Emília; Trpčevská, Jarmila; Pirošková, Jana

    2017-10-01

    In this work, the results of acid leaching of flux skimmings coming from two plants are presented. Sample A contained two phases, Zn(OH)Cl and NH4Cl. In sample B, the presence of three phases, Zn5(OH)8Cl2·H2O, (NH4)2(ZnCl4) and ZnCl2(NH3)2, was proved. The aqueous solution of hydrochloric acid and distilled water was used as the leaching medium. The effects of the leaching time, temperature and concentration of the leaching medium on the zinc extraction were investigated. The apparent activation energy, E a = 4.61 kJ mol-1, and apparent reaction order n = 0.18 for sample A, and the values E a = 6.28 kJ mol-1 and n = 0.33 for sample B were experimentally determined. Zinc leaching in acid medium is a diffusion-controlled process.

  5. Preparation of Rutile from Ilmenite Concentrate Through Pressure Leaching with Hydrochloric Acid

    Science.gov (United States)

    Xiang, Junyi; Liu, Songli; Lv, Xuewei; Bai, Chenguang

    2017-04-01

    Take into account the fact that the natural rutile utilized for the production of titanium dioxide pigment through chloride process is desperately lacking worldwide especially in China, an attempt was exploited for extracting synthetic rutile from Yunnan ilmenite concentrate with hydrochloric acid pressure leaching process. The leaching parameters for one step leaching process were investigated. The results shown that the optimum condition is leaching temperature of 413 K (140 °C), acid concentration of 20 pct HCl, leaching time of 4 hours and liquid/solid mass ratio of 8:1. A two steps leaching process was also suggested to reutilize the leaching liquor which with a high content of HCl. The results showed that the content of HCl decreased from 135 to 75 g/L, total iron increased from 44.5 g/L to about 87.6 g/L, and the liquid/solid mass ratio decreased to 5:1 with a two steps leaching process. The leaching product produced through a two steps leaching process shows a pure golden red with a high content of titanium (92.65 pct TiO2), a relatively low content of calcium (0.10 pct CaO) and magnesium (0.12 pct MgO), but high content of silicon (5.72 pct SiO2).

  6. Kinetics of the Leaching Process of an Australian Gibbsitic Bauxite by Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Aichun Zhao

    2016-01-01

    Full Text Available Gibbsitic bauxite from Australia was leached by hydrochloric acid in this work. Analysis on kinetics for the extraction of Al2O3 was quantitatively studied. It was concluded that the hydrochloric acid leaching process of gibbsitic bauxite was controlled by chemical reaction. Moreover, the mechanism for the dissolution followed the equation, ln⁡k=39.44-1.66×104(1/T, with an apparent activation energy of 137.90 kJ/mol, according to the equation of k=Ae-Ea/RT. This work aims to provide a good theory support for the process control by using a new method of alumina production from the low grade bauxite.

  7. [Newly leaching method of copper from waste print circuit board using hydrochloric acid/n-butylamine/copper sulfate].

    Science.gov (United States)

    Wang, Hong-Yan; Cui, Zhao-Jie; Yao, Ya-Wei

    2010-12-01

    A newly leaching method of copper from waste print circuit board was established by using hydrochloric acid-n-butylamine-copper sulfate mixed solution. The conditions of leaching were optimized by changing the hydrochloric acid, n-butylamine, copper sulfate,temperature and other conditions using copper as target mimics. The results indicated that copper could be leached completely after 8 h at 50 degrees C, hydrochloric acid concentration of 1.75 mol/L, n-butylamine concentration of 0.25 mol/L, and copper sulfate mass of 0.96 g. Under the conditions, copper leaching rates in waste print circuit board samples was up to 95.31% after 9 h. It has many advantages such as better effects, low cost, mild reaction conditions, leaching solution recycling.

  8. Quantitative Leaching of a Spent Cell Phone Printed Circuit Board by Hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Alafara A. Baba

    2014-07-01

    Full Text Available This paper presents a kinetic data on the hydrometallurgical recovery of some metal ions from a printed circuit board (PCB of a spent cell phone by hydrochloric acid leaching. The effects of acid concentration, temperature and particle diameter on the dissolution efficiency at various leaching time intervals were examined. The results of the leaching investigations showed that the powdered cell phone dissolution increases with increasing acid concentration, system temperature with decreasing particle diameter at 360 rpm. With 2M HCl solution, about 88.49% of the sample was dissolved within 120 minutes using 0.075-0.112 mm particle diameter at 800 C. The results of the study indicated that the dissolution reaction could be represented by a shrinking core model with surface chemical reaction. A value of 0.61, 60.67 kJ/mol and 12.9s-1 were calculated as reaction order, activation energy and frequency factor, respectively for the dissolution process.

  9. Effect of hydrochloric acid concentration on the selectivity of leaching of high-calcium dead-burned magnesite

    Directory of Open Access Journals (Sweden)

    Alena Fedoročková

    2010-03-01

    Full Text Available Leaching of particulate dead-burned magnesite with hydrochloric acid at 45 °C was investigated with special regard to the effectof acid concentration (from 0.1 M to 4.8 M on the rate of chemical dissolution of magnesium, calcium and iron. The leaching process wasfound to be mostly selective in the initial stage and the differences in dissolution rates decreased with an increase in the fraction of deadburnedmagnesite reacted.

  10. Separation of Rhenium from Lead-Rich Molybdenite Concentrate via Hydrochloric Acid Leaching Followed by Oxidative Roasting

    Directory of Open Access Journals (Sweden)

    Guanghui Li

    2016-11-01

    Full Text Available Lead-rich molybdenite is a typical rhenium-bearing molybdenum resource in China, which has not been efficiently utilized due to its high contents of lead and gangue minerals. In this study, hydrochloric acid was used for preliminarily removing lead and calcite from a lead-rich molybdenite concentrate. Oxidative roasting-ammonia leaching was then carried out for separation of rhenium and extraction of molybdenum. The hydrochloric acid leaching experiments revealed that 93.6% Pb and 97.4% Ca were removed when the leaching was performed at 95 °C for 10 min with HCl concentration of 8 wt. % and liquid-solid ratio of 5 (mL/g. The results of direct oxidative roasting indicated that 89.3% rhenium was volatilized from the raw concentrate after roasting at 600 °C for 120 min in air. In contrast, the rhenium volatilization was enhanced distinctly to 98.0% after the acid-leached concentrate (leaching residue was roasted at 550 °C for 100 min. By the subsequent ammonia leaching, 91.5% molybdenum was leached out from the calcine produced from oxidative roasting of the acid-leached concentrate, while only 79.3% Mo was leached from the calcine produced by roasting molybdenite concentrate without pretreatment.

  11. Leaching lithium from the anode electrode materials of spent lithium-ion batteries by hydrochloric acid (HCl).

    Science.gov (United States)

    Guo, Yang; Li, Feng; Zhu, Haochen; Li, Guangming; Huang, Juwen; He, Wenzhi

    2016-05-01

    Spent lithium-ion batteries (LIBs) are considered as an important secondary resource for its high contents of valuable components, such as lithium and cobalt. Currently, studies mainly focus on the recycling of cathode electrodes. There are few studies concentrating on the recovery of anode electrodes. In this work, based on the analysis result of high amount of lithium contained in the anode electrode, the acid leaching process was applied to recycle lithium from anode electrodes of spent LIBs. Hydrochloric acid was introduced as leaching reagent, and hydrogen peroxide as reducing agent. Within the range of experiment performed, hydrogen peroxide was found to have little effect on lithium leaching process. The highest leaching recovery of 99.4wt% Li was obtained at leaching temperature of 80°C, 3M hydrochloric acid and S/L ratio of 1:50g/ml for 90min. The graphite configuration with a better crystal structure obtained after the leaching process can also be recycled. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Physical and chemical mechanism underlying ultrasonically enhanced hydrochloric acid leaching of non-oxidative roasting of bastnaesite.

    Science.gov (United States)

    Zhang, Dongliang; Li, Mei; Gao, Kai; Li, Jianfei; Yan, Yujun; Liu, Xingyu

    2017-11-01

    In this study, we investigated an alternative to the conventional hydrochloric acid leaching of roasted bastnaesite. The studies suggested that the rare earth oxyfluorides in non-oxidatively roasted bastnaesite can be selectively leached only at elevated temperatures Further, the Ce(IV) in oxidatively roasted bastnaesite does not leach readily at low temperatures, and it is difficult to induce it to form a complex with F- ions in order to increase the leaching efficiency. Moreover, it is inevitably reduced to Ce(III) at elevated temperatures. Thus, the ultrasonically-assisted hydrochloric acid leaching of non-oxidatively roasted bastnaesite was studied in detail, including, the effects of several process factors and the, physical and chemical mechanisms underlying the leaching process. The results show that the leaching rate for the ultrasonically assisted process at 55°C (65% rare earth oxides) is almost the same as that for the conventional leaching process at 85°C. Based on the obtained results, it is concluded that ultrasonic cavitation plays a key role in the proposed process, resulting not only in a high shear stress, which damages the solid surface, but also in the formation of hydroxyl radicals (OH) and hydrogen peroxide (H2O2). Standard electrode potential analysis and experimental results indicate that Ce(III) isoxidized by the hydroxyl radicals to Ce(IV), which can be leached with F- ions in the form of a complex, and that the Ce(IV) can subsequently be reduced to Ce(III) by the H2O2. This prevents the Cl- ions in the solution from being oxidized to form chlorine. These results imply that the ultrasonically-assisted process can be used for the leaching of non-oxidatively roasted bastnaesite at low temperatures in the absence of a reductant. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Selective recovery of vanadium and scandium by ion exchange with D201 and solvent extraction using P507 from hydrochloric acid leaching solution of red mud.

    Science.gov (United States)

    Zhu, Xiaobo; Li, Wang; Tang, Sen; Zeng, Majian; Bai, Pengyuan; Chen, Lunjian

    2017-05-01

    D201 resin and P507 extractant diluted with sulfonated kerosene were used to respectively separate vanadium and scandium, and impurity ions from hydrochloric acid leaching solution of red mud. More than 99% of vanadium was selectively adsorbed from the hydrochloric acid leaching solution under the conditions of pH value of 1.8, volume ratio of leaching solution to resin of 10, and flow rate of 3.33 mL/min. Maximum extraction and separation of scandium was observed from the acid leaching solution at an aqueous pH value of 0.2. More than 99% of scandium can be selectively extracted using 15% P507, 5% TBP at the aqueous solution/organic phase (A/O) ratio of 10:1 for 6 min. The loaded organic phase was washed with 0.3 mol/L sulfuric acid, wherein most impurities were removed. After the process of desorption or stripping, precipitation, and roasting, high-purity V2O5 and Sc2O3 were obtained. Finally, a conceptual flow sheet was established to separate and recover vanadium and scandium from red mud hydrochloric acid leaching solution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Remediation of soils contaminated with chromium using citric and hydrochloric acids: the role of chromium fractionation in chromium leaching.

    Science.gov (United States)

    Cheng, Shu-Fen; Huang, Chin-Yuan; Tu, Yao-Ting

    2011-01-01

    Acid washing is a common method for soil remediation, but is not always efficient for chromium-contaminated soil. Both soil particle size and the forms of chromium existing in the soil affect the efficiency of soil washing. Laboratory batch and column dissolution experiments were conducted to determine the efficiencies of citric and hydrochloric acids as agents to extract chromium from soils contaminated with chromium. The effects of soil particle size and chromium fractionation on Cr leaching were also investigated. About 90% of chromium in the studied soil existed either in residual form or bound to iron and manganese oxides, and Cr fraction distributions were similar for all soil particle sizes. Almost all exchangeable and carbonate-bound chromium was removed by washing once with 0.5 M HCl, whereas organic chromium was more effectively removed by washing with citric acid rather than with HCl solution of the same concentration. For chromium fractions that were either bound to Fe-Mn oxides or existed as residual forms, the efficiencies of acid washing were usually 20% or less, except for 0.5 M HCl solution, which had much higher efficiencies. Separation of the soil sample by particle size before the separate washing of the soil fractions had little improvement on the chromium removal.

  15. Hydrochloric acid poisoning

    Science.gov (United States)

    ... result in serious infections in the chest and abdominal cavities, which may result in death. Surgery may be needed to repair the perforations. Cancer of the esophagus is a high risk in people who live after ingesting hydrochloric ...

  16. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, C.A., E-mail: carlos.nogueira@lneg.pt [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Paiva, A.P., E-mail: appaiva@fc.ul.pt [Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Oliveira, P.C. [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Costa, M.C., E-mail: mcorada@ualg.pt [Centro de Ciências do Mar, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, A.M. Rosa da, E-mail: amcosta@ualg.pt [Centro de Investigação em Química do Algarve, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal)

    2014-08-15

    Highlights: • A new leaching process based on Cu{sup 2+}/HCl media for recovering Pd and Rh from spent autocatalytic converters is presented. • Palladium and rhodium were efficiently leached, with attained maximum yields of 95% and 86%, respectively. • Temperature, time, and HCl and Cu{sup 2+} concentrations were found to be significant factors in the leaching of Pd and Rh. - Abstract: The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu{sup 2+} concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4 h, [HCl] = 6 M, [Cu{sup 2+}] = 0.3 M)

  17. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters.

    Science.gov (United States)

    Nogueira, C A; Paiva, A P; Oliveira, P C; Costa, M C; da Costa, A M Rosa

    2014-08-15

    The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu(2+) concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4h, [HCl] = 6M, [Cu(2+)] = 0.3M). Copyright © 2014 Elsevier B.V. All rights reserved.

  18. 21 CFR 582.1057 - Hydrochloric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrochloric acid. 582.1057 Section 582.1057 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1057 Hydrochloric acid. (a) Product. Hydrochloric acid. (b) [Reserved] (c) Limitations...

  19. 21 CFR 182.1057 - Hydrochloric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydrochloric acid. 182.1057 Section 182.1057 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1057 Hydrochloric acid. (a) Product. Hydrochloric acid. (b) [Reserved] (c) Limitations...

  20. ARDS following inhalation of hydrochloric acid.

    Science.gov (United States)

    Bansal, D P; Ambegaonkar, Rahul; Radhika, P; Sharma, Manish

    2011-02-01

    The clinical spectrum of Inhalation injury can range from mild cough to a devastating ARDS. We herewith present a patient who is a goldsmith by occupation and his work consists of dissolving gold in Hydrochloric acid. He had accidentally inhaled fumes of Hydrochloric acid and presented with cough and breathlessness, later on required mechanical ventilation for ARDS and improved. This highlights the importance of not to neglect mild symptoms like cough and dyspnea in such a scenario which may have some hidden catastrophe.

  1. Venus clouds - A dirty hydrochloric acid model.

    Science.gov (United States)

    Hapke, B.

    1972-01-01

    The spectral and polarization data for Venus are consistent with micrometer-sized aerosol cloud particles of hydrochloric acid with soluble and insoluble iron compounds, whose source could be volcanic or crustal dust. The yellow color of the clouds could be due to absorption bands in the near UV involving ferric iron and chlorine complexes. It is pointed out that the UV features could arise from variations in the concentrations of iron and hydrochloric acid in the cloud particles.

  2. Venus Clouds: A dirty hydrochloric acid model

    Science.gov (United States)

    Hapke, B.

    1971-01-01

    The spectral and polarization data for Venus are consistent with micron-sized, aerosol cloud particles of hydrochloric acid containing soluble and insoluble iron compounds, whose source could be volcanic or crustal dust. The ultraviolet features could arise from variations in the Fe-HCl concentration in the cloud particles.

  3. 46 CFR 153.557 - Special requirements for hydrochloric acid.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Special requirements for hydrochloric acid. 153.557... Equipment Special Requirements § 153.557 Special requirements for hydrochloric acid. (a) A containment system that carries hydrochloric acid must be lined with: (1) Natural rubber; (2) Neoprene; or (3) A...

  4. 46 CFR 151.50-22 - Hydrochloric acid.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Hydrochloric acid. 151.50-22 Section 151.50-22 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-22 Hydrochloric acid. (a) Hydrochloric acid shall be carried in gravity or pressure type cargo tanks which are independent of the vessel...

  5. Persistent ion pairing in aqueous hydrochloric acid.

    Science.gov (United States)

    Baer, Marcel D; Fulton, John L; Balasubramanian, Mahalingam; Schenter, Gregory K; Mundy, Christopher J

    2014-07-03

    For strong acids, like hydrochloric acid, the complete dissociation into an excess proton and conjugated base as well as the formation of independent solvated charged fragments is assumed. The existence of chloride-hydronium (Cl(-)···H3O(+)) contact ion pairs even in moderate concentration hydrochloric acid (2.5 m) demonstrates that the counterions do not behave merely as spectators. Through comparison of recent extended X-ray absorption fine structure (EXAFS) measurements to state-of-the-art density functional theory (DFT) simulations, we are able to obtain a unique view into the molecular structure of medium-to-high concentrated electrolytes. Here we report that the Cl(-)···H3O(+) contact ion pair structure persists throughout the entire concentration range studied and that these structures differ significantly from moieties studied in microsolvated hydrochloric acid gas phase clusters. Characterizing distinct populations of these ion pairs gives rise to a novel molecular level description of how to view the reaction network for acid dissociation and how it relates to our picture of acid-base equilibria.

  6. Hydrochloric acid recycling from chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Sowieja, D. [Sulzer Escher Wyss GmbH, Ravensburg (Germany); Schaub, M. [Sulzer Chemtech Ltd., Winterthur (Switzerland)

    1993-12-31

    Chlorinated hydrocarbons present a major ecological hazard since most of them are only poorly biodegradable. Incineration is an economical process for their destruction, however the usually recovered sodium or calcium chlorides do not present a value and their disposal may even be very costly. Recovery of hydrochloric acid may therefore present an economical solution, mainly were large quantities of highly chlorinated compounds can be processed (author) 6 refs., 4 figs., 1 tab.

  7. Severe gastrointestinal burn with hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Coskun Araz

    2013-01-01

    Full Text Available Inadvertantly or purposely, an oral intake of corrosive substances may cause life-threatening problems. Early admission to the hospital, clinical and endoscopic evaluation, and early surgery when required, may reduce morbidity and mortality. We report the case of a 49-year-old male patient, who had attempted suicide, by drinking about 800 mL of 25% hydrochloric acid, and who had severe intra-abdominal damage. The aim of this report is to state the fact that a good outcome is possible in severe burns caused by oral intake of corrosive substances, when fast, multidisciplinary, and appropriate management is provided on time.

  8. Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution.

    Science.gov (United States)

    Liu, Hu; Zhang, Shengen; Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin; Volinsky, Alex A

    2014-05-15

    This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Amino-acid contamination of aqueous hydrochloric acid.

    Science.gov (United States)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  10. On-line Determination of Hydrochloric Acid in Process Effluent ...

    African Journals Online (AJOL)

    Prof Van Staden

    volume of the first base being twice to that of the second one and channeled by flow reversal through a reaction coil to the potentiometric sensor. A linear relationship between peak width and logarithm of the hydrochloric acid concentration was obtained in the range 0.025 mol/l - 0.05 mol/l of hydrochloric acid when a ...

  11. Research on the corrosion inhibitors of zinc in hydrochloric acid

    Science.gov (United States)

    Sun, C. X.; Chen, Y. M.; Xu, H. W.; Huang, C. S.; Zhang, M.; Wu, J. Y.; Chen, M.; Xue, M.

    2017-06-01

    Three organic compounds were tested as zinc corrosion inhibitors in hydrochloric acid: cetyltrimethyl ammonium bromide (CTAB), nicotini acid, bromohexadecyl pyridine. The static coupon test results indicate that CTAB and bromohexadecyl pyridine offer the best zinc corrosion protection, while nicotinic acid accelerates zinc corrosion. The polarization results indicate that CTAB, nicotinic acid and bromohexadecyl pyridine induce a positive shift in the E0 of zinc in hydrochloric acid. A complex of CTAB and bromohexadecyl pyridine inhibits the corrosion of zinc in hydrochloric acid. SEM results indicate that the CTAB and bromohexadecyl pyridine formed a uniform and compact membrane on the surface of zinc that subsequently protects the zinc from effective corrosion.

  12. Protonation constants of hydroxybenzenes in hydrochloric acid

    Directory of Open Access Journals (Sweden)

    S. B. TOSIC

    1999-09-01

    Full Text Available The absorption spectra of monohydroxybenzene (Fen, 1,3-dihydroxybenzene (Rez, 1,4-dihydroxybenzene (Hi, 1,2,3-trihydroxybenzene (Pg and 1,3,5-trihydroxybenzene (Fg in aqueous solutions of hydrochloric acid with different values of the Hammett acidity function(H0 have two absorption bands in the region between 190-220 nm and 260-290 nm. This behavior is similar in another mineral acids (H2SO4, H3PO4, HClO4. The absorbance decreases with increasing of acidity (with decreasing of H0 values because of O-protonation. The absorption maxima shift to longer wavelengths, and the graphic dependence of the absorption of the second band as a function of H0 gives characteristic S-curves. These curves show the different effect of the acid on the form the protonation of the investigated hydroxybenzenes. The potonation constants of the hydroxybenzenes were calculated: pKFen=-1.95; pKRez=-2.40; pKHi= -1.93; pKPg=-2.95; pKFg=-1.83.

  13. Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hu [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Shengen, E-mail: zhangshengen@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A. [Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States)

    2014-05-01

    Highlights: • The article provides a new method for recycling rare earth (RE) from waste phosphor. • When compared with the traditional methods, leach rate was much higher. • Y–Eu concentrate and Tb–Ce concentrate were obtained successively. • It would reduce the burden of later extraction, separation and purification. - Abstract: This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y{sub 0.95}Eu{sub 0.05}){sub 2}O{sub 3} in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce{sub 0.67}Tb{sub 0.33}MgAl{sub 11}O{sub 19}) and the Blue phosphor (Ba{sub 0.9}Eu{sub 0.1}MgAl{sub 10}O{sub 17}) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO{sub 2} are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications.

  14. Hydrochloric acid: an overlooked driver of environmental change.

    Science.gov (United States)

    Evans, Chris D; Monteith, Don T; Fowler, David; Cape, J Neil; Brayshaw, Susan

    2011-03-01

    Research on the ecosystem impacts of acidifying pollutants, and measures to control them, has focused almost exclusively on sulfur (S) and nitrogen (N) compounds. Hydrochloric acid (HCl), although emitted by coal burning, has been overlooked as a driver of ecosystem change because most of it was considered to redeposit close to emission sources rather than in remote natural ecosystems. Despite receiving little regulatory attention, measures to reduce S emissions, and changes in energy supply, have led to a 95% reduction in United Kingdom HCl emissions within 20 years. Long-term precipitation, surface water, and soil solution data suggest that the near-disappearance of HCl from deposition could account for 30-40% of chemical recovery from acidification during this time, affecting both near-source and remote areas. Because HCl is highly mobile in reducing environments, it is a more potent acidifier of wetlands than S or N, and HCl may have been the major driver of past peatland acidification. Reduced HCl loadings could therefore have affected the peatland carbon cycle, contributing to increases in dissolved organic carbon leaching to surface waters. With many regions increasingly reliant on coal for power generation, HCl should be recognized as a potentially significant constituent of resulting emissions, with distinctive ecosystem impacts.

  15. Enhancement of hydrolysis of Chlorella vulgaris by hydrochloric acid.

    Science.gov (United States)

    Park, Charnho; Lee, Ja Hyun; Yang, Xiaoguang; Yoo, Hah Young; Lee, Ju Hun; Lee, Soo Kweon; Kim, Seung Wook

    2016-06-01

    Chlorella vulgaris is considered as one of the potential sources of biomass for bio-based products because it consists of large amounts of carbohydrates. In this study, hydrothermal acid hydrolysis with five different acids (hydrochloric acid, nitric acid, peracetic acid, phosphoric acid, and sulfuric acid) was carried out to produce fermentable sugars (glucose, galactose). The hydrothermal acid hydrolysis by hydrochloric acid showed the highest sugar production. C. vulgaris was hydrolyzed with various concentrations of hydrochloric acid [0.5-10 % (w/w)] and microalgal biomass [20-140 g/L (w/v)] at 121 °C for 20 min. Among the concentrations examined, 2 % hydrochloric acid with 100 g/L biomass yielded the highest conversion of carbohydrates (92.5 %) into reducing sugars. The hydrolysate thus produced from C. vulgaris was fermented using the yeast Brettanomyces custersii H1-603 and obtained bioethanol yield of 0.37 g/g of algal sugars.

  16. Dissolution Kinetics of Icel-Aydincik Dolomite in Hydrochloric Acid

    African Journals Online (AJOL)

    NJD

    The dissolution of Icel-Aydincik dolomite in aqueous hydrochloric acid solution was investigated with respect to the effects of acid/dolomite mole ..... reaction temperature increases. 3.6. Dissolution Rates. In order to calculate the dissolution rates, the derivative of the concentration-time plot is necessary. One mole of Ca2+ ...

  17. Surface roughness of composite resins subjected to hydrochloric acid.

    Science.gov (United States)

    Roque, Ana Carolina Cabral; Bohner, Lauren Oliveira Lima; de Godoi, Ana Paula Terossi; Colucci, Vivian; Corona, Silmara Aparecida Milori; Catirse, Alma Blásida Concepción Elizaur Benitez

    2015-01-01

    The purpose of this study was to determine the influence of hydrochloric acid on surface roughness of composite resins subjected to brushing. Sixty samples measuring 2 mm thick x 6 mm diameter were prepared and used as experimental units. The study presented a 3x2 factorial design, in which the factors were composite resin (n=20), at 3 levels: microhybrid composite (Z100), nanofilled composite (FiltekTM Supreme), nanohybrid composite (Ice), and acid challenge (n=10) at 2 levels: absence and presence. Acid challenge was performed by immersion of specimens in hydrochloric acid (pH 1.2) for 1 min, 4 times per day for 7 days. The specimens not subjected to acid challenge were stored in 15 mL of artificial saliva at 37 oC. Afterwards, all specimens were submitted to abrasive challenge by a brushing cycle performed with a 200 g weight at a speed of 356 rpm, totaling 17.8 cycles. Surface roughness measurements (Ra) were performed and analyzed by ANOVA and Tukey test (p≤0.05). Surface roughness values were higher in the presence (1.07±0.24) as compared with the absence of hydrochloric acid (0.72±0.04). Surface roughness values were higher for microhybrid (1.01±0.27) compared with nanofilled (0.68 ±0.09) and nanohybrid (0.48±0.15) composites when the specimens were not subjects to acid challenge. In the presence of hydrochloric acid, microhybrid (1.26±0.28) and nanofilled (1.18±0,30) composites presents higher surface roughness values compared with nanohybrid (0.77±0.15). The hydrochloric acid affected the surface roughness of composite resin subjected to brushing.

  18. On-line Determination of Hydrochloric Acid in Process Effluent ...

    African Journals Online (AJOL)

    The sample is sandwiched between two titrants in a holding coil, with the volume of the first base being twice to that of the second one and channeled by flow reversal through a reaction coil to the potentiometric sensor. A linear relationship between peak width and logarithm of the hydrochloric acid concentration was ...

  19. [Study on optimization of the hydrolysis process of dioscin catalyzed by hydrochloric acid].

    Science.gov (United States)

    Li, Qian; Gao, Xiang-Tao; Zhao, Wen-Lei; Liu, Xiu-Hua

    2008-07-01

    To study the optimization of hydrolysis process of dioscin catalyzed by hydrochloric acid. The effects of hydrochloric acid concentration, reaction temperature, reaction time and their interactions had been investigated using orthogonal design and single-factor experiments. The optimum hydrolysis conditions were as follows: reaction temperature 90 degrees C, reaction time 3h, hydrochloric acid concentration 2.0 mol/L. Hydrochloric acid concentration and reaction temperature should be controlled because of their remarkable influence on hydrolysis process.

  20. 9 CFR 96.13 - Uncertified casings; disinfection with hydrochloric acid.

    Science.gov (United States)

    2010-01-01

    ... hydrochloric acid. 96.13 Section 96.13 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... Uncertified casings; disinfection with hydrochloric acid. Foreign animal casings offered for importation into... mix. Add 23/4 gallons (10.35 liters) C. P. hydrochloric acid containing not less than 35 percent...

  1. An unusual presentation of hydrochloric acid ingestion: a mystery unraveled.

    Science.gov (United States)

    Ganapathy, Vinod Prabhu; Das, Rashmi Ranjan; Chinnakkannan, Selvakumar; Panda, Shasanka Shekhar

    2015-03-01

    Unintentional acid ingestion is less commonly encountered than alkali ingestion. The injury develops for hours to days after ingestion and often results in progressively increasing difficulty in airway management. However, gastric perforation is rare. A 3-year-old boy presented to us with an orotonsillopharyngeal membrane and severe upper airway obstruction. Subsequently, he was diagnosed with a case of gastric perforation due to unintentional hydrochloric acid ingestion. He was treated with partial gastrectomy and feeding jejunostomy, and the recovery was good. Unintentional hydrochloric acid ingestion is rare in children. The manifestations masquerade many other clinical conditions, and the diagnosis is difficult in cases in which history of ingestion is not available. Treatment is symptomatic, and emergency surgery is indicated in case of gastrointestinal perforation.

  2. Accidental intoxication with hydrochloric acid and hydrofluoric acid mixture

    Directory of Open Access Journals (Sweden)

    Anna Smędra-Kaźmirska

    2014-08-01

    Full Text Available The paper describes a fatal case of accidental ingestion of a mixture of hydrochloric acid and hydrofluoric acid. The man was admitted to hospital, where appropriate treatment, adequate to his condition, was instituted. Numerous ventricular fibrillation episodes, for which the patient was defibrillated repeatedly, were observed during the period of hospitalization. The patient was in a critical condition, with progressive symptoms of hypovolemic shock and multiorgan failure. On the next day after admission, signs of electromechanical dissociation progressing to asystole were noted. The instituted resuscitation procedure proved ineffective and the patient died. Autopsy revealed brownish discoloration of the esophageal, gastric, and small intestinal mucous membranes. Numerous ulcerations without signs of perforation were found both in the esophagus and in the stomach. The mucous membrane of the small intestine demonstrated focal rubefactions, whereas no focal lesions of the large intestinal mucosa were seen. Microscopic investigation of the biopsy specimens collected from the stomach, duodenum and small intestine revealed mucous membrane necrosis foci, reaching the deeper layers of the wall of these organs. The mucous membrane of the large intestine was congested. Bioptates obtained from the lungs indicated the presence of hemorrhagic infarcts and focal extravasations. Poisoning with the aforementioned acids with consequent necrosis of the esophageal, gastric, duodenal and small intestinal walls with hemorrhages to the gastrointestinal tract, as well as extravasations and hemorrhagic infarcts in the lungs was considered to be the cause of death.

  3. Fatal Course of a Suicidal Intoxication with Hydrochloric Acid

    Science.gov (United States)

    Koschny, Ronald; Herceg, Maria; Stremmel, Wolfgang; Eisenbach, Christoph

    2013-01-01

    Suicidal ingestion of undiluted hydrochloric acid is a rare but live-threatening event. We report on the dramatic and fulminant course of a 61-year-old woman who drank 200 ml of 30–33% hydrochloric acid. On admission to our intensive care unit she was alert and oriented with stable vital signs. Gastroscopy demonstrated complete necrosis from the hypopharynx to the pylorus, which was flushed continuously via drainage catheters. At that time point perforation was not evident. Shortly thereafter she developed an acute abdomen and a tension pneumothorax which was decompressed. CT scan demonstrated esophageal and intestinal perforation with massive mediastinal necrosis. On emergency laparostomy she showed complete necrosis of the intestine and stomach. The patient died 10 h after admission from multiorgan failure. The therapeutic options are critically discussed in comparison to previously reported cases in the literature. PMID:23569439

  4. In situ end labelling: effect of proteolytic enzyme pretreatment and hydrochloric acid.

    Science.gov (United States)

    Carr, N. J.; Talbot, I. C.

    1997-01-01

    AIM: To determine the effect of dilute hydrochloric acid on the in situ end labelling (ISEL) reaction, with and without a variety of different proteolytic enzymes. METHODS: Sections of tissue fixed in buffered formalin were pretreated with trypsin, protease XIV (at two different concentrations), or protease XXIV (for two different incubation times), with and without subsequent 1 M hydrochloric acid treatment. The results were compared with those obtained using hydrochloric acid alone, with proteinase K, and pepsin pretreatment, and with no pretreatment. RESULTS: When hydrochloric acid was added to the sections in addition to trypsin, protease XIV, and protease XXIV, there was a significant increase in ISEL reactivity in both apoptotic nuclei and morphologically normal nuclei. Hydrochloric acid alone had no significant effect. CONCLUSIONS: Hydrochloric acid has a distinctive effect on the ISEL reaction that is dependent on prior proteolytic digestion. Images PMID:9292152

  5. In situ end labelling: effect of proteolytic enzyme pretreatment and hydrochloric acid.

    OpenAIRE

    Carr, N. J.; Talbot, I. C.

    1997-01-01

    AIM: To determine the effect of dilute hydrochloric acid on the in situ end labelling (ISEL) reaction, with and without a variety of different proteolytic enzymes. METHODS: Sections of tissue fixed in buffered formalin were pretreated with trypsin, protease XIV (at two different concentrations), or protease XXIV (for two different incubation times), with and without subsequent 1 M hydrochloric acid treatment. The results were compared with those obtained using hydrochloric acid alone, with pr...

  6. 46 CFR 151.50-76 - Hydrochloric acid, spent (NTE 15%).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Hydrochloric acid, spent (NTE 15%). 151.50-76 Section... Hydrochloric acid, spent (NTE 15%). (a)(1) Gravity type cargo tanks must be designed and tested to meet the... by the Commandant (CG-522). Openings must be fitted with bolted cover plates and acid-resistant...

  7. Gas production after reaction of sodium bicarbonate and hydrochloric acid.

    Science.gov (United States)

    Fordtran, J S; Morawski, S G; Santa Ana, C A; Rector, F C

    1984-11-01

    Ingestion of sodium bicarbonate has been implicated as one of the proximate causes of spontaneous gastric rupture. However, the volume and rate of gas released from the reaction of ingested sodium bicarbonate and gastric acid has not been previously studied in detail. We, therefore, developed an in vitro method for measuring gas release after addition of sodium bicarbonate to a solution containing hydrochloric acid. From the results of our studies, we conclude that even though hydrochloric acid and sodium bicarbonate react instantaneously, the resulting gas production is slow, mainly because CO2 produced from the dehydration of carbonic acid dissolves in water and is only slowly released into the gas phase. The major exogenous factors that determine the rate of gas release are the volume of the solution, the quantity of reactants, the air volume over the reaction mixture, the partial pressure of CO2 of the acid solution before the addition of bicarbonate, and the stirring rate. The presence of food, alcohol, and carbonic anhydrase had relatively little if any effect. Based on our results, we believe that ingestion of the recommended dose of sodium bicarbonate (one-half teaspoon) would result in only small amounts of sudden gas release, probably not enough to be an important factor in causing spontaneous gastric rupture. On the other hand, we measured the amount of sodium bicarbonate that people actually select to take for indigestion, and all exceeded the recommended dose. Some people selected doses of bicarbonate that would result in several hundred milliliters of gas release within 3 min; it seems likely that such injudicious ingestion of sodium bicarbonate, if taken when the stomach was distended with air, food, and liquid, could be an important factor in spontaneous gastric rupture.

  8. Enamel structural changes induced by hydrochloric and phosphoric acid treatment.

    Science.gov (United States)

    Bertacci, Angelica; Lucchese, Alessandra; Taddei, Paola; Gherlone, Enrico F; Chersoni, Stefano

    2014-12-30

    The aim of this study was to evaluate enamel acid-induced structural changes after 2 different treatments, by means of Raman and infrared (IR) spectroscopy analyses, and to correlate these findings with permeability measured as fluid discharge from outer enamel. Two different treatments were investigated: 10 enamel slices were etched with 15% hydrochloric acid (HCl) for 120 seconds and 10 slices with 37% phosphoric acid gel (H3PO4) for 30 seconds, rinsed for 30 seconds and then air-dried for 20 seconds. Powders of enamel treated as previously described were produced. Replicas of enamel subjected to the same treatments were obtained to evaluate the presence of fluid droplets on enamel surface. Raman and IR spectroscopy showed that the treatment with both hydrochloric and phosphoric acids induced a decrease in the carbonate content of the enamel apatite. At the same time, both acids induced the formation of HPO42- ions. After H3PO4 treatment, the bands due to the organic component of enamel decreased in intensity, while they increased after HCl treatment. Replicas of H3PO4 treated enamel showed a strongly reduced permeability. Replicas of HCl 15% treated samples showed a maintained permeability. A decrease of the enamel organic component, as resulted after H3PO4 treatment, involves a decrease in enamel permeability, while the increase of the organic matter (achieved by HCl treatment) still maintains enamel permeability.The results suggested a correlation between organic matter and enamel permeability. Permeability was affected by etching technique and could be involved in marginal seal, gap and discoloration at the enamel interface, still causes of restoration failure.

  9. In situ transesterification of highly wet microalgae using hydrochloric acid.

    Science.gov (United States)

    Kim, Bora; Im, Hanjin; Lee, Jae W

    2015-06-01

    This study addresses in situ transesterification of highly wet microalgae with hydrochloric acid (HCl) as a catalyst. In situ transesterification was performed by heating the mixture of wet algal cells, HCl, methanol, and solvent in one pot, resulting in the fatty acid methyl ester (FAME) yield over 90% at 95°C. The effects of reaction variables of temperature, amounts of catalyst, reactant, and solvent, and type of solvents on the yield were investigated. Compared with the catalytic effect of H2SO4, in situ transesterification using HCl has benefits of being less affected by moisture levels that are as high as or above 80%, and requiring less amounts of catalyst and solvent. For an equimolar amount of catalyst, HCl showed 15wt.% higher FAME yield than H2SO4. This in situ transesterification using HCl as a catalyst would help to realize a feasible way to produce biodiesel from wet microalgae. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Efficient regioselective O3-monodesilylation by hydrochloric acid in cyclodextrins.

    Science.gov (United States)

    Gu, Jiamin; Chen, Tong; Wang, Qifang; Chen, Tieyu; Ling, Chang-Chun

    2015-06-17

    An efficient O3-monodesilylation method has been developed for the derivatization of per-3-O-silylated cyclodextrin (CD) derivatives. Using hydrochloric acid as a reagent, the O3-monodesilylation was found to be regioselective, mild, practical and general as it can be applied to all α-, β- and γ-CDs. The advantage of the methodology is that the acid-catalyzed O3-desilylation can be carried out in a stepwise manner so that different types of functional groups can be introduced to a CD molecule at different stage of the O3-desilylations. This makes the current methodology flexible and versatile. This current methodology constitutes one of the few methodologies available for the regioselective modification of CDs at the secondary face. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Kinetic study of free fatty acid esterification reaction catalyzed by recoverable and reusable hydrochloric acid.

    Science.gov (United States)

    Su, Chia-Hung

    2013-02-01

    The catalytic performance and recoverability of several homogeneous acid catalysts (hydrochloric, sulfuric, and nitric acids) for the esterification of enzyme-hydrolyzed free fatty acid (FFA) and methanol were studied. Although all tested catalysts drove the reaction to a high yield, hydrochloric acid was the only catalyst that could be considerably recovered and reused. The kinetics of the esterification reaction catalyzed by hydrochloric acid was investigated under varying catalyst loading (0.1-1M), reaction temperature (303-343K), and methanol/FFA molar ratio (1:1-20:1). In addition, a pseudo-homogeneous kinetic model incorporating the above factors was developed. A good agreement (r(2)=0.98) between the experimental and calculated data was obtained, thus proving the reliability of the model. Furthermore, the reusability of hydrochloric acid in FFA esterification can be predicted by the developed model. The recoverable hydrochloric acid achieved high yields of FFA esterification within five times of reuse. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Hydrochloric acid method of beneficiating magnesite using a pilot plant

    Energy Technology Data Exchange (ETDEWEB)

    Sertin, V.A.; Galkin, Y.M.; Gemusova, I.B.; Glezer, E.B.; Khaltyurin, V.A.; Kislitsyn, V.I.; Rodde, T.V.; Simonov, K.V.; Vetlugina, N.A.; Yurlova, L.N.; Zakutinskii, V.L.

    1985-07-01

    One feature of the HCl treatment of magnesite is the possibility of using the main mass of HCl in a closed cycle. Regeneration of the HCl takes place during the thermal hydrolysis of the purified solution of magnesium chloride. In accordance with the plan drawn up by the Eastern Institute of Refractories and the Ukranian Institute of Chemistry, a pilot plant has been built at the Magnesite Combine; this has been mastered and is used for the hydrochloric acid treatment of magnesite; the annual productivity of the equipment is 400 tons. Some features of the process of dissolution of natural and caustic magnesite in HCL and the sintering of the beneficiated product have been considered elsewhere. This paper pays particular attention to the apparatus-process character and considers in more detail the hydrolysis of magnesium chloride.

  13. Synthesis of alkali metal platinates and their dissolution behavior in hydrochloric acid

    National Research Council Canada - National Science Library

    KASUYA, Ryo; MIKI, Takeshi; MORIKAWA, Hisashi; TAI, Yutaka

    2013-01-01

    To decrease the environmental load due to current Pt dissolution processes that use strong acids in combination with oxidizing agents, the synthesis and dissolution of alkali metal platinates in hydrochloric acid (HCl) were examined...

  14. 40 CFR 63.1218 - What are the standards for hydrochloric acid production furnaces that burn hazardous waste?

    Science.gov (United States)

    2010-07-01

    ... Boilers, and Hydrochloric Acid Production Furnaces § 63.1218 What are the standards for hydrochloric acid... 40 Protection of Environment 11 2010-07-01 2010-07-01 true What are the standards for hydrochloric acid production furnaces that burn hazardous waste? 63.1218 Section 63.1218 Protection of Environment...

  15. EDTA and hydrochloric acid effects on mercury accumulation by Lupinus albus.

    Science.gov (United States)

    Rodríguez, Luis; Alonso-Azcárate, Jacinto; Villaseñor, José; Rodríguez-Castellanos, Laura

    2016-12-01

    The efficiency of white lupine (Lupinus albus) to uptake and accumulate mercury from a soil polluted by mining activities was assessed in a pot experiment with chemically assisted phytoextraction. The mobilizing agents tested were ethylenediaminetetracetic acid (EDTA) and hydrochloric acid (HCl). Two doses of each amendment were used (0.5 and 1.0 g of amendment per kg of soil), and unamended pots were used as a control. Addition of HCl to the soil did not negatively affect plant biomass, while the use of EDTA led to a significant decrease in plant growth when compared to that found for non-treated pots, with plants visually showing symptoms of toxicity. The addition of hydrochloric acid increased root, shoot and total plant Hg uptake of white lupine by 3.7 times, 3.1 times and 3.5 times, respectively, in relation to non-amended plants. The greatest efficiency was obtained for the highest HCl dose. EDTA led to higher concentrations of total plant Hg than that found with the control, but, due to the aforementioned decrease in plant biomass, the Hg phytoextraction yield was not significantly increased. These results were attributed to the capability of both amendments to form stable Hg complexes. The concentration of Hg in the water of the soil pores after the phytoextraction experiment was very low for all treatments, showing that risks derived from metal leaching could be partially avoided by using doses and chemicals suitable to the concentration of metal in the soil and plant performance.

  16. STIMULATION BY HYDROCHLORIC ACID AND BY THE NORMAL ALIPHATIC ACIDS IN THE SUNFISH EUPOMOTIS

    Science.gov (United States)

    Allison, James B.

    1932-01-01

    1. The reaction of the sunfish, Eupomotis gibbosus, to different concentrations of hydrochloric acid and of the first six members of the N aliphatic acids has been studied. 2. The stimulating efficiency of hydrochloric acid may best be related to the concentration of hydrogen ions produced by that acid. 3. The stimulating efficiency of the N aliphatic acids may best be correlated with the non-polar nature of a portion of the molecule, but it is necessary to consider the higher potential of the polar group of formic acid to account satisfactorily for its position in the series. 4. When equally effective concentrations of the N aliphatic acids are compared, formic acid is more effective at lower concentrations than at higher. 5. Per cent variation in response appears to be independent of the chemical environment to which the animal responded. PMID:19872671

  17. Serpentine dissolution in hydrochloric acid for carbon dioxide sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Amankwah, R.K.; Pickles, C.A. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mining Engineering

    2008-07-01

    Increased carbon dioxide concentrations in the atmosphere can be attributed to industrialization and the associated combustion of large amounts of fossil fuels. The release of carbon dioxide into the atmosphere causes greenhouse gases, which is expected to have a destabilizing effect on the climate. Several methods have been investigated to reduce the amount of greenhouse gases in the atmosphere, such as improved energy efficiency and conservation programs; utilization of alternative energy sources; and carbon dioxide sequestration. This paper discussed the sequestration of carbon dioxide by minerals as a potential method for reducing the greenhouse gas concentration in the atmosphere. The paper presented a study that involved the dissolution of lizardite, a serpentine mineral, in hydrochloric acid at high pressures in an autoclave. The thermodynamics of the system were examined and experimental data were presented. The solubility of the mineral was shown to be strongly dependent on processing time, acid concentration and pulp density but not strongly affected by stirring or temperature. The paper also discussed the characterization of the reacted samples by thermogravimetric analysis, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The reacted samples were compared to the as-received material. It was concluded that the equilibrium calculations, the kinetic experiments and the characterization of the processed samples indicated that a silica-rich layer formed on the lizardite as the magnesium dissolved, and that this layer hindered further dissolution. 13 refs., 1 tab., 8 figs.

  18. Laboratory investigation of three distinct emissions monitors for hydrochloric acid.

    Science.gov (United States)

    Dene, Charles E; Pisano, John T; Durbin, Thomas D; Bumiller, Kurt; Crabbe, Keith; Muzio, Lawrence J

    2016-12-01

    The measurement of hydrochloric acid (HCl) on a continuous basis in coal-fired plants is expected to become more important if HCl standards become implemented as part of the Federal Mercury and Air Toxics Standards (MATS) standards that are under consideration. For this study, the operational performance of three methods/instruments, including tunable diode laser absorption spectroscopy (TDLAS), cavity ring down spectroscopy (CRDS), and Fourier transform infrared (FTIR) spectroscopy, were evaluated over a range of real-world operating environments. Evaluations were done over an HCl concentration range of 0-25 ppmv and temperatures of 25, 100, and 185 °C. The average differences with respect to temperature were 3.0% for the TDL for values over 2.0 ppmv and 6.9% of all concentrations, 3.3% for the CRDS, and 4.5% for the FTIR. Interference tests for H2O, SO2, and CO, CO2, and NO for a range of concentrations typical of flue gases from coal-fired power plants did not show any strong interferences. The possible exception was an interference from H2O with the FTIR. The instrument average precision over the entire range was 4.4% for the TDL with better precision seen for concentrations levels of 2.0 ppmv and above, 2.5% for the CRDS, and 3.5% for the FTIR. The minimum detection limits were all on the order of 0.25 ppmv, or less, utilizing the TDL values with a 5-m path. Zero drift was found to be 1.48% for the TDL, 0.88% for the CRDS, and 1.28% for the FTIR. This study provides an evaluation of the operational performance of three methods/instruments, including TDL absorption spectroscopy (TDLAS), cavity ring down spectroscopy (CRDS), and FTIR spectroscopy, for the measurement of hydrochloric acid (HCl) over a range of real-world operating environments. The results showed good instrument accuracy as a function of temperature and no strong interferences for flue gases typical to coal-fired power plants. The results show that these instruments would be viable for the

  19. Laboratory testing of a continuous emissions monitor for hydrochloric acid.

    Science.gov (United States)

    Dene, Chuck; Pisano, John T; Durbin, Thomas D; Bumiller, Kurt; Crabbe, Keith; Muzio, Lawrence J

    2014-06-01

    Continuous monitoring of exhaust flue gas has become a common practice in power plants in response to Federal Mercury and Air Toxics Standards (MATS) standards. Under the current rules, hydrochloric acid (HCl) is not continuously measured at most plants; however, MATS standards have been proposed for HCl, and tunable diode laser (TDL) absorption spectroscopy is one method that can be used to measure HCl continuously. The focus of this work is on the evaluation and verification of the operation performance of an HCL TDL over a range of real-world operating environments. The testing was conducted at the University of California at Riverside (UCR) spectroscopy evaluation laboratory. Laboratory tests were conducted at three separate temperatures, 25 degrees C, 100 degrees C, and 200 degrees C, and two distinct moisture levels for the enhanced temperatures, 0%, (2 tests) and 4%, over a concentration range from 0 ppmv to 25 ppmv-m at each of the elevated temperatures. The results showed good instrument accuracy as afunction of changing temperature and moisture. Data analysis showed that the average percentage difference between the ammonia concentration and the calibration source was 3.33% for varying moisture from 0% to 4% and 2.69%for varying temperature from 25 to 100/200 degrees C. An HCl absorption line of 1.742 microm was selected for by the manufacturer for this instrument. The Hi Tran database indicated that CO2 is probably the only major interferent, although the CO2 absorption is very weak at that wavelength. Interference tests for NO, CO, SO2, NH3, and CO2 for a range of concentrations typical of flue gasses in coal-fired power plants did not show any interference with TDL HCl measurements at 1.742 microm. For these interference tests, CO2 was tested at a concentration of 11.9% concentration in N2 for these tests. Average precision over the entire range for all 10 tests is 3.12%. The focus of this study was.an evaluation of the operation performance of a

  20. Fatal myocardial infarction after hydrochloric acid ingestion in a suicide attempt.

    Science.gov (United States)

    Sari, Ibrahim; Zengin, Suat; Pehlivan, Yavuz; Davutoglu, Vedat; Yildirim, Cuma

    2008-06-01

    Ingestion of acid-containing household products either accidentally or for suicide attempt is a common form of intoxication. Hydrochloric acid is widely used as an antirust compound or cleaner in homes and is highly corrosive and generally causes coagulation necrosis which could lead to perforation in the gastrointestinal system. Although hydrochloric acid ingestion is mainly harmful to the gastrointestinal system, it may also cause metabolic acidosis, hemolysis, renal failure, and fatality as well. Cardiovascular manifestations of hydrochloric acid ingestion are extremely rare, and we report a 48-year-old man who died of acute inferolateral myocardial infarction after hydrochloric acid ingestion in a suicide attempt who had no history of coronary artery disease. In conclusion, although cardiovascular manifestations of hydrochloric acid ingestion are extremely rare, the ingestion may still cause myocardial infarction which could be fatal. Physicians dealing with hydrochloric acid ingestion in the ED should be aware of this possibility and always obtain serial electrocardiograms even if the patient has no cardiac complaint.

  1. Dissolution of Platinum in Hydrochloric Acid Under Industrial-Scale Alternating Current Polarization

    Science.gov (United States)

    Myrzabekov, B. E.; Bayeshov, A. B.; Makhanbetov, A. B.; Mishra, B.; Baigenzhenov, O. S.

    2018-02-01

    The electrochemical behavior of platinum in a hydrochloric acid solution under polarization by an industrial-scale alternating current has been investigated. For the electrical dissolution of platinum, titanium is used as an auxiliary electrode, which increases the yield of platinum dissolution by 12.5 pct. The influence of the concentration of hydrochloric acid, the current densities of the platinum and titanium electrodes, and the temperature of the electrolyte on the efficiency of the process of dissolving platinum have all been studied.

  2. Application of ultrasound-assisted acid leaching procedures for major and trace elements determination in edible seaweed by inductively coupled plasma-optical emission spectrometry.

    Science.gov (United States)

    Domínguez-González, Raquel; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Adela; Bermejo-Barrera, Pilar

    2005-05-15

    A new method using diluted reagents (nitric and hydrochloric acids and oxygen peroxide) and ultrasound energy to assist metals acid leaching with from edible seaweed was optimized. The method uses a first sonication at high temperature with hydrochloric acid as a previous stage to an ultrasound-assisted acid leaching with 7ml of an acid solution containing nitric acid, hydrochloric acid and hydrogen peroxide at concentrations of 3.7, 3.0 and 3.0M, respectively. Optimum conditions for the first sonication step were ultrasound energy at 17kHz, sonication temperature at 65 degrees C, an acid volume of 2ml, an hydrochloric acid concentration of 6.0M and a sonication time of 10min. It has been found that the first sonication stage at high temperature with hydrochloric acid is necessary to obtain quantitative recoveries for As, Ba, Fe and V. Otherwise quantitative recoveries were reached for the other elements investigated (Ca, K, Na, Mg, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The repeatability of the ultrasound-assisted acid leaching method was around 10% for all elements. Adequate limit of detection and limit of quantification were reached by using inductively coupled plasma-optical emission spectrometry (ICP-OES) for measurements. The method resulted accurate after analysing several seaweed certified reference materials (IAEA-140/TM, NIES-03 and NIES-09). The method was finally applied to the multi-element determination in edible seaweed samples.

  3. Rinsing with antacid suspension reduces hydrochloric acid-induced erosion.

    Science.gov (United States)

    Alves, Maria do Socorro Coelho; Mantilla, Taís Fonseca; Bridi, Enrico Coser; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes; Amaral, Flávia Lucisano Botelho; Turssi, Cecilia Pedroso

    2016-01-01

    Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin. The experimental units were 48 slabs (3×3×2mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25mL of a hydrochloric acid (HCl) solution (0.01M, pH 2) for 2min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10mL of antacid suspension (Gaviscon(®), Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl+antacid suspension; (b) erosive challenge with HCl+deionized water (DIW); (c) no erosive challenge+antacid suspension; (d) no erosive challenge+DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey's tests. Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p=0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p=0.026). The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. A Mineralogical Assessment on Residues after Acidic Leaching of Bauxite Residue (Red Mud for Titanium Recovery

    Directory of Open Access Journals (Sweden)

    Gözde Alkan

    2017-10-01

    Full Text Available Due to its alkalinity, red mud produced by the Bayer process may affect both the environment and human health. For this reason, its further utilization instead of disposal is of great importance. Numerous methods have already been studied for hydrometallurgical treatment of red mud, especially for the recovery of various metallic components such as iron, aluminum, titanium or rare earth elements. This study focuses on the extraction of titanium from red mud and in particular the mineralogical changes, induced by leaching. Sulfuric acid, hydrochloric acid and their combination have been utilized as leaching agents with the same leaching parameters. It has been determined that sulfuric acid is the best candidate for the red mud treatment in terms of titanium leaching efficiency at the end of 2 h with a value of 67.3%. Moreover, samples from intermediate times of reaction revealed that leaching of Ti exhibit various reaction rates at different times of reaction depending on acid type. In order to explain differences, X-ray Diffraction (XRD, scanning electron microscope (SEM and QEMSCAN techniques were utilized. Beside titanium oxide (TiO2 with available free surface area, a certain amount of the TiO2 was detected as entrapped in Fe dominating oxide. These associations between Ti and Fe phases were used to explain different leaching reaction rates and a reaction mechanism was proposed to open a process window.

  5. Effects of acid leaching aluminum from reservoir bottom sediment ...

    African Journals Online (AJOL)

    Comparison of before and after leaching, the spectra showed that the mineral composition of chlorite disappeared after acid leaching with a sound effect. Among the three acids, sulfuric acid is the best leaching solution under same operating conditions. The best combination for maximum extraction in this study is 5 N ...

  6. Direct Acid Leaching of Vanadium from Stone Coal

    Science.gov (United States)

    Zhang, Bo; Gao, Zhaoguo; Liu, Hongzhao; Wang, Wei; Cao, Yaohua

    2017-09-01

    This paper focused on optimizing the process conditions of direct acid leaching process to enhance the leaching efficiency of leaching vanadium from the stone coal. Orthogonal experiments and single factor experiments were conducted to investigate the effect of the influential factors of direct acid leaching on vanadium leaching ratio. The results showed that the vanadium leaching ratio reached the maximum value of 89.22 % under the optimal process conditions of CaF2 dosage 5 mass%, H2SO4 dosage 40 mass%, leaching temperature 95 °C and leaching time 10 h. Furthermore, the reaction mechanisms of the main influencing factors were analyzed. Finally, the two-stage counter-current leaching process was adopted to decrease the consumption of sulfuric acid and neutralizer, and the results indicated that the consumption of sulfuric acid decreased 12.50 % as well as neutralizer decreased 35.80 %.

  7. Inhibition of corrosion of mild steel in hydrochloric acid by some azo ...

    African Journals Online (AJOL)

    Inhibition of corrosion of mild steel in hydrochloric acid by some azo dyes. EE Ebenso. Abstract. No Abstract. Nigerian Journal of Chemical Research Vol. 6 2001: 8-12. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Article Metrics. Metrics Loading ... Metrics ...

  8. ST-segment elevation mimicking myocardial infarction after hydrochloric acid ingestion: Acute caustic myocarditis.

    Science.gov (United States)

    San Antonio, Rodolfo; Pujol López, Margarida; Perea, Rosario Jesús; Sabaté, Manel

    ST-segment elevation after hydrochloric acid ingestion has barely been described in the literature, without identification of its causal mechanism. We hypothesize that acute caustic myocarditis, by direct contact between necrotic upper gastrointestinal tract and pericardium may induce the ECG findings. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  9. Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

    Science.gov (United States)

    Kitabayashi, Suguru; Nakano, Masayoshi; Nishikawa, Kazuyuki; Koga, Nobuyoshi

    2016-01-01

    A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and…

  10. Depolymerization and de-N-acetylation of chitin oligomers in hydrochloric acid.

    Science.gov (United States)

    Einbu, Aslak; Vårum, Kjell M

    2007-01-01

    The monosaccharide 2-amino-2-deoxy-D-glucose (glucosamine, GlcN) has recently drawn much attention in relation to its use to treat or prevent osteoarthritis in humans. Glucosamine is prepared from chitin, a process that is performed in concentrated acid, such as hydrochloric acid. This process involves two acid-catalyzed processes, that is, the hydrolysis of the glycosidic linkages (depolymerization) and of the N-acetyl linkages (de-N-acetylation). The depolymerization reaction has previously been found to be much faster compared to the deacetylation, with the consequence that the chitin chain will first be hydrolyzed to the monomer 2-acetamido-2-deoxy-D-glucose (N-acetylglucosamine, GlcNAc) which is subsequently deacetylated. We have found that the chitin disaccharide GlcNAc(1-->4)GlcNAc could be completely hydrolyzed to the monosaccharide GlcNAc with negligible concomitant de-N-acetylation, and the chitin disaccharide and monosaccharide were further used to study the depolymerization reaction and the de-N-acetylation reaction, respectively. The reactions were performed in hydrochloric acid as a function of acid concentration (3-12 M) and temperature (20-35 degrees C), and 1H-NMR spectroscopy was used to monitor the reaction rates. The 1H NMR spectrum of GlcNAc in concentrated (12 M) and deuterated hydrochloric acid at 25 degrees C was assigned. The glucofuranosyl oxazolinium (3) ion was found to exist in equilibrium with the alpha- and beta-anomers of the pyranose form of GlcNAc, where 3 was present in half the total molar concentrations of the two anomeric forms of GlcNAc. At lower acid concentration (3-6 M), only trace concentrations of 3 could be detected. The rate of de-N-acetylation of GlcNAc was determined as a function of hydrochloric acid concentration, showing a maximum at 6 M and decreasing by a factor of 2 upon decreasing or increasing the acid concentration to 3 or 12 M. The activation energy for hydrolysis of the N-acetyl linkage of GlcNAc was

  11. Comparable effects of capsaicin-containing red pepper sauce and hydrochloric acid on secondary peristalsis in humans.

    Science.gov (United States)

    Chen, Chien-Lin; Yi, Chih-Hsun; Liu, Tso-Tsai

    2013-11-01

    We aimed to evaluate whether acute esophageal instillation of capsaicin and hydrochloric acid had different effects on distension-induced secondary peristalsis. Secondary peristalsis was induced by slow and rapid air injections into the mid-esophagus after the evaluation of baseline motility in 16 healthy subjects. The effects on secondary peristalsis were determined by esophageal instillation with capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg) and hydrochloric acid (0.1 N). The administration of capsaicin induced a significant increase in the visual analogue scale score for heartburn as compared with hydrochloric acid (P = 0.002). The threshold volume for generating secondary peristalsis during slow and rapid air distensions did not differ between capsaicin and hydrochloric acid infusions. Hydrochloric acid significantly increased the frequency of secondary peristalsis in response to rapid air distension compared with capsaicin infusion (P = 0.03). Pressure wave amplitude during slow air distension was greater with the infusion of hydrochloric acid than capsaicin infusion (P = 0.001). The pressure wave duration during rapid air distension was longer after capsaicin infusion than hydrochloric acid infusion (P = 0.01). The pressure wave amplitude during rapid air distension was similar between capsaicin and hydrochloric acid infusions. Despite subtle differences in physiological characteristics of secondary peristalsis, acute esophageal instillation of capsaicin and hydrochloric acid produced comparable effects on distension-induced secondary peristalsis. Our data suggest the coexistence of both acid- and capsaicin-sensitive afferents in human esophagus which produce similar physiological alterations in secondary peristalsis. © 2013 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

  12. Extraction of gallium(III) from hydrochloric acid solutions by trioctylammonium-based mixed ionic liquids.

    Science.gov (United States)

    Katsuta, Shoichi; Okai, Miho; Yoshimoto, Yuki; Kudo, Yoshihiro

    2012-01-01

    The extractabilities of aluminium(III), gallium(III), and indium(III) from hydrochloric acid solutions were investigated using a mixture of two protic ionic liquids, trioctylammonium bis(trifluoromethanesulfonyl)amide ([TOAH][NTf(2)]) and trioctylammonium nitrate ([TOAH][NO(3)]). At a HCl concentration of 4 mol L(-1) or more, gallium(III) was nearly quantitatively extracted and the extractability order was Ga > Al > In. The extractability of gallium(III) increased with increasing [TOAH][NO(3)] content in the mixed ionic liquid. The extracted gallium(III) was quantitatively stripped with aqueous nitric acid solutions. The separation and recovery of gallium(III) from hydrochloric acid solutions containing excess indium(III) was demonstrated using the mixed ionic liquid.

  13. Mechanochemical leaching of chalcopyrite concentrate by sulfuric acid

    Science.gov (United States)

    Mohammadabad, Farhad Khorramshahi; Hejazi, Sina; khaki, Jalil Vahdati; Babakhani, Abolfazl

    2016-04-01

    This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the leaching (mechanochemical leaching) of chalcopyrite concentrates in a sulfuric acid medium at room temperature and atmospheric pressure. High energy ball milling process was used during the leaching to provide the mechanochemical leaching condition, and atomic absorption spectroscopy and cyclic voltammetry were used to determine the leaching behavior of chalcopyrite. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the chalcopyrite powder before and after leaching. The results demonstrated that mechanochemical leaching was effective; the extraction of copper increased significantly and continuously. Although the leaching efficiency of chalcopyrite was very low at ambient temperature, the percentages of copper dissolved in the presence of hydrogen peroxide (H2O2) and ferric sulfate (Fe2(SO4)3) after 20 h of mechanochemical leaching reached 28% and 33%, respectively. Given the efficiency of the developed method and the facts that it does not require the use of an autoclave and can be conducted at room temperature and atmospheric pressure, it represents an economical and easy-to-use method for the leaching industry.

  14. Robust antifogging antireflective coatings on polymer substrates by hydrochloric acid vapor treatment.

    Science.gov (United States)

    Li, Tong; He, Junhui; Yao, Lin; Geng, Zhi

    2015-04-15

    Antireflective coatings on polymer substrates have received significant attention for their potential applications. In this paper, robust microporous antifogging antireflective coatings on polymer substrates were prepared from acid-catalyzed silica sol followed by hydrochloric acid vapor solidification at mild temperature below glass transition temperatures of common polymers. The coatings passed 3H pencil hardness test, sand flow test and water-drop test. They had excellent antireflective and antifogging properties. The maximum transmittance of coatings on PMMA substrates reached 100.0% (the maximum transmittance wavelength could be regulated) and average transmittance reached 99.0% in 400-800 nm. The advantage and mechanism of hydrochloric acid vapor solidification and mechanical strength enhancement of coatings are discussed in contrast to ammonia vapor treatment and air vapor treatment. The hydrochloric acid vapor treatment results in a dense integrated microporous film structure. Optical properties were characterized by a UV-Vis spectrophotometer. Surface wettability was studied by a contact angle/interface system. Surface morphologies and structures of coatings were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom force microscopy (AFM). Copyright © 2014 Elsevier Inc. All rights reserved.

  15. The effects of hydrochloric acid on all-ceramic restorative materials: an in-vitro study.

    Science.gov (United States)

    Harryparsad, A; Dullabh, H; Sykes, L; Herbst, D

    2014-04-01

    The aim of this in-vitro study was to assess the long-term effects of hydrochloric acid on the surface roughness of three all-ceramic restorative materials CEREC VITABLOC Mark II CAD, IPS Empress CAD and IPS e.max CAD. Six cylindrical specimens (10mm diameter, 3mm height) of each material type were prepared, using the CEREC CAD/CAM machine. The unpolished samples were immersed in 15ml hydrochloric acid (pH 2) at 37 degrees C. Before immersion (baseline) and at periods of 7.5 hours, 45 hours and 91 hours, the specimens were removed from the acid and two randomised areas (10 microm X 10 microm) were selected and tested on each. The atomic force microscope (Bruker Dimension icon) was used to assess surface roughness and surface area at baseline and after each exposure time. The materials were compared over time with respect to surface roughness and surface area (baseline, 1 month, 6 months, 1 year) in a repeated measures analysis of variance (ANOVA). Sample groups differed significantly for roughness (p hydrochloric acid.

  16. The Effect of Temperature and Acid Concentration on Corrosion of Low Carbon Steel in Hydrochloric Acid Media

    OpenAIRE

    Anees A. Khadom; Aprael S. Yaro; Abdul A.H. Kadum; Ahmed S. AlTaie; Ahmed Y. Musa

    2009-01-01

    Problem statement: The effect of different temperatures and acid concentrations on the corrosion of low carbon steel in hydrochloric acid were addressed in this study. Approach: The effect of temperature was explained by application of Arrhenius equation and transition state theory, while the acid concentration effect was explained using reaction kinetic equations. The combined effect of temperature and acid concentration then modeled using a nonlinear regression method. Results: A detail of ...

  17. A Concentrated Hydrochloric Acid-based Method for Complete Recovery of DNA from Bone.

    Science.gov (United States)

    Huynen, Leon; Lambert, David M

    2015-11-01

    The successful extraction of DNA from historical or ancient animal bone is important for the analysis of discriminating genetic markers. Methods used currently rely on the digestion of bone with EDTA and proteinase K, followed by purification with phenol/chloroform and silica bed binding. We have developed a simple concentrated hydrochloric acid-based method that precludes the use of phenol/chloroform purification and can lead to a several-fold increase in DNA yield when compared to other commonly used methods. Concentrated hydrochloric acid was shown to dissolve most of the undigested bone and allowed the efficient recovery of DNA fragments <100 bases in length. This method should prove useful for the recovery of DNAs from highly degraded animal bone, such as that found in historical or ancient samples. © 2015 American Academy of Forensic Sciences.

  18. Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid

    Science.gov (United States)

    Ramya, K.; Mohan, Revathi; Joseph, Abraham

    2014-11-01

    Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (Δ E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 Å. This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.

  19. Inhibition of the corrosion of mild steel in hydrochloric acid by isatin ...

    African Journals Online (AJOL)

    The inhibition of corrosion of mild steel in hydrochloric acid by isatin glycine (ING) and isatin (IN) at 30-60 oC and concentrations of 0.0001 M to 0.0005 M was studied via weight loss method. At the highest inhibitor concentration studied ING exhibited inhibition efficiency of 87% while IN exhibited 84% at 60 oC. A chemical ...

  20. Hydrochloric acid aerosol formation by the interaction of hydrogen chloride with humid air

    Science.gov (United States)

    Rhein, R. A.

    1973-01-01

    The conditions in which hydrochloric acid aerosol is predicted by the interaction of hydrogen chloride gas with the water vapor in humid air are analyzed. The liquid gas phase equilibrium for the HCL-H2O system is expressed in terms of relative humidity and hydrogen chloride concentration as parts per million, units commonly used in pollution studies. Presented are the concentration (wt %) of HC1 in the aerosol and the concentration of aerosol (ppm) predicted.

  1. The Formation of Hydrochloric Acid Aerosol from the Interaction of the Space Shuttle Rocket Exhaust with the Atmosphere

    Science.gov (United States)

    Rhein, R. A.

    1973-01-01

    A description is given of conditions of atmospheric temperature and relative humidity under which hydrochloric acid aerosol is expected upon interaction of the proposed space shuttle rocket exhaust products with the atmosphere.

  2. Fact Sheet - Final Air Toxics Rule for Steel Pickling and HCI Process Facilities and Hydrochloric Acid Regeneration Plants

    Science.gov (United States)

    Fact Sheet summarizing the main points of the national emssions standard for hazaradous air pollutants (NESHAP) for Steel Pickling— HCl Process Facilities and Hydrochloric Acid Regeneration Plants as promulgated on June 22, 1999.

  3. Recovery of uranium from low concentration leach liquor of acid in-situ leaching

    Science.gov (United States)

    Wen, Zhenqian; Niu, Yuqing

    2017-04-01

    For problems of environment protection and cost in uranium recycle, the process flows of ion exchange and Eluex, which recovered uranium from low concentration leach liquor of acid in-situ leaching, were studied. Although the flow sheet of ion exchange process was simple, the Eluex process had an advantage over it due to large quantity of effluent and high processing cost in ion exchange process by comparative studies.

  4. Investigating the Acid Failure of Aluminium Alloy in 2 M Hydrochloric Acid Using Vernonia amygdalina

    Directory of Open Access Journals (Sweden)

    Olugbenga A. Omotosho

    2012-04-01

    Full Text Available The acid failure of aluminium alloy in 2 M hydrochloric acid solution in the presence of Vernonia amygdalina extract was investigated using gasometric technique. Aluminium alloy coupons of dimension 4 cm by 1 cm were immersed in test solutions of free acid and also those containing extract volumes of 2, 3, 4 and 5 cm3 at ambient temperature for 30 minutes. The volumes of hydrogen gas evolved as a result of the rate of reaction were recorded and analyzed. Analysis revealed that maximum inhibitor efficiency which corresponds to the lowest corrosion rate was obtained at optimum inhibitor volumes of 5 cm3, with reduction in the corrosion rate observed to follow in order of increasing extract volumes. Adsorption study revealed that Temkin isotherm best described the metal surface interaction with the extract phytochemicals, with 12 minutes becoming the best exposure time for the phytochemicals to adsorb to the metal surface at all volumes. Statistical modelling of the corrosion rate yielded an important relationship suitable for estimating corrosion rate values once volumes of the extract is known. Microstructural studies, showed an indirect relationship between crack growth rates and extract volumes, while consistency of the irregular intermetallic phases increases with increasing extract volumes.

  5. Reductive Leaching of Low-Grade Pyrolusite with Formic Acid

    Science.gov (United States)

    Lu, Youzhi; Ma, Huaju; Huang, Runjun; Yuan, Aiqun; Huang, Zengwei; Zhou, Zeguang

    2015-08-01

    The extraction of manganese from low-grade pyrolusite is investigated using formic acid as reductant in sulfuric acid medium. The effects of volumes of formic acid, concentration of sulfuric acid, liquid to solid ratio (L/S), leaching time, and temperature on leaching efficiency of manganese, iron, and aluminum are valuated with single-factor experiments. The results show that the leaching efficiency of manganese reached 90.08 pct with 80.70 pct of iron and 31.55 pct of aluminum under the optical conditions: 15 pct H2SO4(v/v) 60 ml, 4 ml formic acid, and 2 hours leaching time at 363 K (90 °C).

  6. Comparison between phosphoric acid and hydrochloric acid in microabrasion technique for the treatment of dental fluorosis.

    Science.gov (United States)

    Bassir, Mahshid Mohammadi; Bagheri, Golnaz

    2013-01-01

    To compare the effectiveness of phosphoric acid (H(3)PO(4))-pumice compound with conventional hydrochloric acid (HCl)-pumice compound in treating different severities of dental fluorosis with the microabrasion technique. Sixty-seven anterior teeth from seven patients with different severities of dental fluorosis were treated. In each patient, half of the teeth were treated with HCl-pumice compound and the other half with H(3)PO(4)-pumice compound (split-mouth design). Both treatment compounds were applied for 30-second periods and treatment continued up to 10 minutes. Before and after treatment, standardized photographs were taken. The photographs were compared by two experienced observers unaware of the modality of treatment. Two indices of aesthetics, improvement in appearance (IA) and degree of stain removal (DSR), were determined according to a visual analog scale. The inter- and intra-correlation coefficients were made; then, statistical analyses were calculated using Mann-Whitney and t-test. There were no significant differences in interobserver evaluation. Improvements in aesthetic indices were observed in all fluorotic teeth by both compounds; however, the mean treatment time with HCl-pumice was significantly lower than H(3)PO(4)-pumice. The H(3)PO(4)-pumice compound improved aesthetic indices in fluorotic teeth similar to the HCl-pumice compound.

  7. Comparison between phosphoric acid and hydrochloric acid in microabrasion technique for the treatment of dental fluorosis

    Science.gov (United States)

    Bassir, Mahshid Mohammadi; Bagheri, Golnaz

    2013-01-01

    Purpose: To compare the effectiveness of phosphoric acid (H3PO4)-pumice compound with conventional hydrochloric acid (HCl)-pumice compound in treating different severities of dental fluorosis with the microabrasion technique. Materials and Methods: Sixty-seven anterior teeth from seven patients with different severities of dental fluorosis were treated. In each patient, half of the teeth were treated with HCl-pumice compound and the other half with H3PO4-pumice compound (split-mouth design). Both treatment compounds were applied for 30-second periods and treatment continued up to 10 minutes. Before and after treatment, standardized photographs were taken. The photographs were compared by two experienced observers unaware of the modality of treatment. Two indices of aesthetics, improvement in appearance (IA) and degree of stain removal (DSR), were determined according to a visual analog scale. The inter- and intra-correlation coefficients were made; then, statistical analyses were calculated using Mann-Whitney and t-test. Results: There were no significant differences in interobserver evaluation. Improvements in aesthetic indices were observed in all fluorotic teeth by both compounds; however, the mean treatment time with HCl-pumice was significantly lower than H3PO4-pumice. Conclusion: The H3PO4-pumice compound improved aesthetic indices in fluorotic teeth similar to the HCl-pumice compound. PMID:23349575

  8. Sulfuric, hydrochloric, and nitric acid-catalyzed triacetone triperoxide (TATP) reaction mixtures: an aging study.

    Science.gov (United States)

    Fitzgerald, Mark; Bilusich, Daniel

    2011-09-01

    The organic peroxide explosive triacetone triperoxide (TATP) is regularly encountered by law enforcement agents in various stages of its production. This study utilizes solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) to examine sulfuric acid-, hydrochloric acid-, and nitric acid-catalyzed TATP syntheses during the initial 24 h of these reactions at low temperatures (5-9°C). Additionally, aging of the reaction mixtures was examined at both low and ambient temperatures (19-21°C) for a further 9 days. For each experiment, TATP could be readily identified in the headspace above the reaction mixture 1 h subsequent to the combination of reagents; at 24 h, TATP and diacetone diperoxide (DADP) were prominent. TATP degraded more rapidly than DADP. Additionally, chlorinated acetones chloroacetone and 1,1,-dichloroacetone were identified in the headspace above the hydrochloric acid-catalyzed TATP reaction mixture. These were not present when the catalyst was sulfuric acid or nitric acid. 2011 American Academy of Forensic Sciences. Published 2011. This article is a U.S. Government work and is in the public domain in the U.S.A.

  9. Escherichia coli and Salmonella enterica Are Protected against Acetic Acid, but Not Hydrochloric Acid, by Hypertonicity▿

    Science.gov (United States)

    Chapman, B.; Ross, T.

    2009-01-01

    Chapman et al. (B. Chapman, N. Jensen, T Ross, and M. B. Cole, Appl. Environ. Microbiol. 72:5165-5172, 2006) demonstrated that an increased NaCl concentration prolongs survival of Escherichia coli O157 SERL 2 in a broth model simulating the aqueous phase of a food dressing or sauce containing acetic acid. We examined the responses of five other E. coli strains and four Salmonella enterica strains to increasing concentrations of NaCl under conditions of lethal acidity and observed that the average “lag” time prior to inactivation decreases in the presence of hydrochloric acid but not in the presence of acetic acid. For E. coli in the presence of acetic acid, the lag time increased with increasing NaCl concentrations up to 2 to 4% at pH 4.0, up to 4 to 6% at pH 3.8, and up to 4 to 7% (wt/wt of water) NaCl at pH 3.6. Salmonella was inactivated more rapidly by combined acetic acid and NaCl stresses than E. coli, but increasing NaCl concentrations still decreased the lag time prior to inactivation in the presence of acetic acid; at pH 4.0 up to 1 to 4% NaCl was protective, and at pH 3.8 up to 1 to 2% NaCl delayed the onset of inactivation. Sublethal injury kinetics suggest that this complex response is a balance between the lethal effects of acetic acid, against which NaCl is apparently protective, and the lethal effects of the NaCl itself. Compared against 3% NaCl, 10% (wt/wt of water) sucrose with 0.5% NaCl (which has similar osmotic potential) was found to be equally protective against adverse acetic acid conditions. We propose that hypertonicity may directly affect the rate of diffusion of acetic acid into cells and hence cell survival. PMID:19346344

  10. Quantitative leaching of galena | Olanipekun | Bulletin of the ...

    African Journals Online (AJOL)

    1999-09-25

    Abstract. (Received September 25, 1999; revised January 19, 2000) Experiments on the quantitative leaching of lead from galena in hydrochloric acid solutions are reported. The effects of contact time, acid concentration, number of leaching stages, solid to liquid ratio, particle size, temperature, and stirring speed, on the ...

  11. Hydrochloric vs. sulphuric acid in water for Ziehl-Neelsen staining of acid-fast bacilli.

    Science.gov (United States)

    Aung, K J M; Nandi, P; Hamid Salim, A; Hossain, A; Van Deun, A

    2011-07-01

    Damien Foundation Bangladesh tuberculosis (TB) control projects. To compare 25% sulphuric acid in water (H(2)SO(4)) with hydrochloric acid in water (HCl) to differentiate acid-fast bacilli in sputum smears stained with 1% carbolfuchsin. For 1 year, all 158 microscopy laboratories used either H(2)SO(4) or 3%/6%/10% HCl for their routine work, alternating monthly between H(2)SO(4) and HCl. Each month a sample of five smears per laboratory was rechecked blind. After recording qualitative staining aspects, all sample smears were restained before rechecking, using H(2)SO(4) for destaining. A total of 368,059 H(2)SO(4) and 335,436 HCl smears were routinely read, yielding 7.2% positive or scanty results in both groups. Of these, 9492 were rechecked. There was no difference in false-negatives detected (0.66%, 95%CI 0.44-0.95 for H(2)SO(4) vs. 0.68%, 95%CI 0.46-0.98 for HCl), but apparently there were more false-positives with H(2)SO(4) (2.12%, 95%CI 0.92-4.14 vs. 0.28%, 95%CI 0.00-1.54, P = 0.05). Qualitatively, only 3% HCl yielded significantly inferior differentiation results. HCl 6-10% in water can be recommended for Ziehl-Neelsen destaining above H(2)SO(4). Diluting is easier and safer, and it may cause less confusion with false-positives during rechecking, including a restaining step.

  12. Ginger extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

    Science.gov (United States)

    Fidrusli, A.; Suryanto; Mahmood, M.

    2018-01-01

    Ginger extract as corrosion inhibitor from natural resources was studied to prevent corrosion of mild steel in acid media. Ginger rhizome was extracted to produce green corrosion inhibitor (G-1) while ginger powder bought at supermarket was also extract to form green corrosion inhibitor (G-2). Effectiveness of inhibitor in preventing corrosion process of mild steel was studied in 1.0 M of hydrochloric acid. The experiment of weight loss method and polarization technique were conducted to measure corrosion rate and inhibition efficiency of mild steel in solution containing 1.0 M of hydrochloric acid with various concentration of inhibitor at room temperature. The results showed that, the rate of corrosion dropped from 8.09 mmpy in solution containing no inhibitor to 0.72 mmpy in solution containing 150g/l inhibitor while inhibition efficiency up to 91% was obtained. The polarization curve in polarization experiments shows that the inhibition efficiency is 86% with high concentration of inhibitor. The adsorption of ginger extract on the surface of mild steel was observed by using optical microscope and the characterization analysis was done by using pH measurement method. When high concentration of green inhibitor in the acid solution is used, the pH at the surface of steel is increasing.

  13. ST segment elevation associated with hydrochloric acid ingestion: A case report.

    Science.gov (United States)

    Yeh, I-Jeng; Liu, Kuan-Ting

    2017-11-01

    Electrocardiography (ECG) was used to diagnose acute coronary syndrome, but many other diseases may also result in ST segment change. We report one case of ingested hydrochloric acid present with ST segment elevation in the ECG. However, subsequent coronary angiography did not reveal significant coronary occlusion. An 83-year-old female was transferred to our emergency department (ED) from the branch hospital due to ingestion of toilet bowl cleaner containing 9.5% hydrochloric acid. She complained about chest pain and 12-lead ECG showed ST segment elevation at lead II, III, and aVF. The blood examinations revealed elevation of aspartate transaminase (69 IU/L), thrombocytopenia (62,000/μL), and acidosis (pH 7.311, pCO2 27 mm Hg, HCO3 13.3 mmol/L). Creatine kinase-MB and troponin I did not elevate then. After transferred to our ED, coronary angiography was done within 1 hour. Angiography showed 60% stenosis in the segment 7 of left anterior descending coronary artery and 30% nonsignificant stenosis in the segment 2 of right coronary artery, with no apical ballooning. No significant lesion consistent with ST segment elevation myocardial infarction was found. Conservative treatment was chosen. Bradycardia was followed by cardiac arrest that developed 4 hours later. Cardiopulmonary resuscitation was applied and the patient became shock status after return of spontaneous circulation. The patient was admitted to the intensive care unit and expired on next day. Patients of ingested hydrochloric acid present with ST segment elevation in the ECG may not indicate coronary artery disease. This ECG finding may be a poor prognostic index in such patients. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  14. Diluted hydrochloric acid generates larger radiofrequency ablation lesions in excised porcine livers.

    Science.gov (United States)

    Luo, Rong-Guang; Fao, Fei; Huang, Jin-Hua; Gu, Yang-Kui; Jiang, Xiong-Ying; Huang, Ying-Jie

    2013-01-01

    This study evaluated the influence of continuous infusion of diluted hydrochloric acid during radiofrequency ablation (RFA) on the size of ablated lesions. Experiments were performed in 20 excised porcine livers using three different treatment modalities: (1) normal saline-enhanced RFA (NS-RFA), which was normal saline pumped into ablated tissue during RFA; (2) diluted hydrochloric acid ablation (DHAA), which was 3 mol/L diluted hydrochloric acid (HCl) injected into hepatic tissue without RFA; and (3) HCl-enhanced RFA (HCl-RFA), which was 3 mol/L diluted HCl continuously infused into ablated tissue during RFA. We produced 20 HCl-RFA and NS-RFA lesions, respectively, using a monopolar perfusion electrode connected to a commercially available radiofrequency generator, and 20 DHAA lesions using an 18-gauge Chiba needle. The ablated lesions were evaluated both macroscopically and histologically. Dimensions of lesions were compared among HCl-RFA, NS-RFA, and DHAA. The ablated lesions had an elliptical-like shape and were well-demarcated with normal liver tissue. The mean volume, longitudinal diameter, and transverse diameter of NS-RFA lesions were 11.24±0.29 cm(3), 3.4±0.07 cm, and 2.48±0.03 cm, those of HCl-RFA lesions were 58.14±3.05 cm(3), 5.51±0.05 cm, and 4.49±0.11 cm, and those of DHAA lesions were 4.41±0.16 cm(3), 2.43±0.08 cm, and 1.8±0.03 cm, respectively. The mean dimensions of HCl-RFA lesions were the largest among the three types of ablation (P < 0.001). Under the present experimental conditions, the continuous infusion of diluted HCl during RFA can generate larger ablated lesions than NS-RFA or DHAA in excised porcine livers.

  15. Effect of molecular structure of aniline-formaldehyde copolymers on corrosion inhibition of mild steel in hydrochloric acid solution.

    Science.gov (United States)

    Zhang, Yan; Nie, Mengyan; Wang, Xiutong; Zhu, Yukun; Shi, Fuhua; Yu, Jianqiang; Hou, Baorong

    2015-05-30

    Aniline-formaldehyde copolymers with different molecular structures have been prepared and investigated for the purpose of corrosion control of mild steel in hydrochloric acid. The copolymers were synthesized by a condensation polymerization process with different ratios of aniline to formaldehyde in acidic precursor solutions. The corrosion inhibition efficiency of as-synthesized copolymers for Q235 mild steel was investigated in 1.0 mol L(-1) hydrochloric acid solution by weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. All the results demonstrate that as-prepared aniline-formaldehyde copolymers are efficient mixed-type corrosion inhibitors for mild steels in hydrochloric acid. The corrosion inhibition mechanism is discussed in terms of the role of molecular structure on adsorption of the copolymers onto the steel surface in acid solution. Copyright © 2015. Published by Elsevier B.V.

  16. Hydrochloric acid aerosol and gaseous hydrogen chloride partitioning in a cloud contaminated by solid rocket exhaust

    Science.gov (United States)

    Sebacher, D. I.; Bendura, R. J.; Wornom, D. E.

    1980-01-01

    Partitioning of hydrogen chloride between hydrochloric acid aerosol and gaseous HCl in the lower atmosphere was experimentally investigated in a solid rocket exhaust cloud diluted with humid ambient air. Airborne measurements were obtained of gaseous HCl, total HCl, relative humidity and temperature to evaluate the conditions under which aerosol formation occurs in the troposphere in the presence of hygroscopic HCl vapor. Equilibrium predictions of HCl aerosol formation accurately predict the measured HCl partitioning over a range of total HCl concentrations from 0.6 to 16 ppm.

  17. Synthesis of hydrochloric acid solution for total mercury determination in natural waters.

    Science.gov (United States)

    Patel-Sorrentino, Nathalie; Benaim, Jean-Yves; Cossa, Daniel; Lucas, Yves

    2011-01-01

    Total mercury (Hg(T)) determination requires the addition of concentrated hydrochloric acid solution (≥10 mol L(-1) HCl) in relatively high amounts to preserve the samples and to prepare reagent solutions. A method for the preparation of concentrated HCl with Hg(T) concentration of lower than 5 ng L(-1) is described in this article. It is based on the well-known chemical reaction: 2 NH(4)Cl + H(2)SO(4) → (NH(4))(2)SO(4) + 2 HCl. This method is validated thanks to the US Environmental Protection Agency method 1631 and standard reference materials BCR-579 (mercury in coastal seawater).

  18. Solvent Extraction of Tungsten(VI) from Moderate Hydrochloric Acid Solutions with LIX 63

    Energy Technology Data Exchange (ETDEWEB)

    Truong, Hoai Thanh; Lee, Man Seung [Mokpo National University, Jeollanamdo (Korea, Republic of); Kim, Yong Hwan [Incheon Technology Service Centre, Incheon (Korea, Republic of)

    2017-06-15

    The solvent extraction of tungsten(VI) from hydrochloric acid solutions using 5,8-diethyl-7-hydroxydodecan-6-one oxime (LIX 63) was analyzed in solutions having an initial pH range from 2 to 5, by varying the concentration of metal and extractant. In our experimental range, the cationic exchange reaction as well as the solvation reaction occurred simultaneously. The cation exchange reaction was identified by applying a slope analysis method to the extraction data. The existence of cationic tungsten(VI) species was confirmed by ion exchange experiments with Diphonix resin at pH 3. Further study is needed to identify the nature of this tungsten cationic species.

  19. Inhibition Effect of Miconazole Nitrate on the Corrosion of Mild Steel in Hydrochloric Acid Medium

    Directory of Open Access Journals (Sweden)

    J. Ishwara Bhat

    2011-01-01

    Full Text Available The corrosion inhibition of mild steel by miconazole nitrate, an antifungal drug has been investigated using potentiodynamic polarization, electrochemical impedance spectroscopy technique, and weight loss methods. The experimental results suggested miconazole nitrate is a good corrosion inhibitor for mild steel in 1 M hydrochloric acid medium. The inhibition efficiency increased with increase in inhibitor concentration. The thermodynamic parameters were determined and discussed. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the surface of mild steel following Langmuir adsorption isotherm.

  20. Microarray-based transcriptome of Listeria monocytogenes adapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid.

    Science.gov (United States)

    Tessema, Girum Tadesse; Møretrø, Trond; Snipen, Lars; Heir, Even; Holck, Askild; Naterstad, Kristine; Axelsson, Lars

    2012-09-01

    Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies.

  1. Pretreatment of corn stover for sugar production using dilute hydrochloric acid followed by lime.

    Science.gov (United States)

    Zu, Shuai; Li, Wen-zhi; Zhang, Mingjian; Li, Zihong; Wang, Ziyu; Jameel, Hasan; Chang, Hou-min

    2014-01-01

    In this study, a two stage process was evaluated to increase the sugar recovery. Firstly, corn stover was treated with diluted hydrochloric acid to maximize the xylose yield, and then the residue was treated with lime to alter the lignin structure and swell the cellulose surface. The optimal condition was 120 °C and 40 min for diluted hydrochloric acid pretreatment followed by lime pretreatment at 60 °C for 12h with lime loading at 0.1 g/g of substrate. The glucose and xylose yield was 78.0% and 97.0%, respectively, with cellulase dosage at 5 FPU/g of substrate. The total glucose yield increased to 85.9% when the cellulase loading was increased to 10 FPU/g of substrate. This two stage process was effective due to the swelling of the internal surface, an increase in the porosity and a decrease in the degree of polymerization. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis

    Science.gov (United States)

    Aldersley, Michael Frank; Joshi, Prakash C.; Huang, Yixing

    2017-09-01

    The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

  3. The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis.

    Science.gov (United States)

    Aldersley, Michael Frank; Joshi, Prakash C; Huang, Yixing

    2017-09-01

    The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

  4. Quantitative leaching of a Nigerian chalcopyrite ore by nitric acid ...

    African Journals Online (AJOL)

    Due to increasing uses of copper nitrate, Cu(NO3)2, as catalysts, textile and polishing agents for other metals, experiment on the leaching of a Nigerian chalcopyrite ore by nitric acid for possible production of copper nitrate was examined. The effects of acid concentration, temperature and particle size on the dissolution ...

  5. Acid leaching of natural chrysotile asbestos to mesoporous silica fibers

    Science.gov (United States)

    Maletaškić, Jelena; Stanković, Nadežda; Daneu, Nina; Babić, Biljana; Stoiljković, Milovan; Yoshida, Katsumi; Matović, Branko

    2017-10-01

    Nanofibrous silica with a high surface area was produced from chrysotile by the acid-leaching method. Natural mineral chrysotile asbestos from Stragari, Korlace in Serbia was used as the starting material. The fibers were modified by chemical treatment with 1 M HCl and the mineral dissolution was monitored by transmission electron microscopy, X-ray powder diffraction, inductively coupled plasma spectrometry and low-temperature nitrogen adsorption techniques to highlight the effects of the leaching process. The results showed that the applied concentration of acid solution and processing time of 4 h were sufficient to effectively remove the magnesium hydroxide layer and transform the crystal structure of the hazardous starting chrysotile to porous SiO2 nanofibers. With prolonged acid leaching, the specific surface area, S BET, calculated by BET equation, was increased from 147 up to 435 m2 g- 1, with micropores representing a significant part of the specific surface.

  6. A Modified Hydroxyproline Assay Based on Hydrochloric Acid in Ehrlich's Solution Accurately Measures Tissue Collagen Content.

    Science.gov (United States)

    Cissell, Derek D; Link, Jarrett M; Hu, Jerry C; Athanasiou, Kyriacos A

    2017-04-01

    Collagen quantification has long been relevant to biomedical research and clinical practice to characterize tissues and determine disease states. The hydroxyproline assay, while a broadly employed method of quantifying collagen, uses perchloric acid to dissolve Ehrlich's reagent. Since perchloric acid poses occupational safety hazards and high costs, in this study, a new hydroxyproline assay was developed that replaces perchloric acid with a relatively safer and cheaper alternative, hydrochloric acid (HCl). To validate this biochemical technique, first, using either acid to dissolve Ehrlich's reagent, the assays were completed for native and engineered collagenous tissues. No statistical differences were identified between the assays (p = 0.32). Subsequently, both biochemical techniques were compared to amino acid analysis, considered a proteomics gold standard. Interestingly, utilizing HCl in lieu of perchloric acid yielded greater concordance with amino acid analysis (ρc = 0.980) than did the traditional assay (ρc = 0.947); that is, the HCl-based assay more closely estimates hydroxyproline content, and, consequently, true collagen content. Thus, using Ehrlich's reagent containing HCl in the hydroxyproline assay represents an advance in both mitigating laboratory safety hazards and improving biochemical collagen quantification.

  7. Effect of beverages on bovine dental enamel subjected to erosive challenge with hydrochloric acid.

    Science.gov (United States)

    Amoras, Dinah Ribeiro; Corona, Silmara Aparecida Milori; Rodrigues, Antonio Luiz; Serra, Mônica Campos

    2012-01-01

    This study evaluated by an in vitro model the effect of beverages on dental enamel previously subjected to erosive challenge with hydrochloric acid. The factor under study was the type of beverage, in five levels: Sprite® Zero Low-calorie Soda Lime (positive control), Parmalat® ultra high temperature (UHT) milk, Ades® Original soymilk, Leão® Ice Tea Zero ready-to-drink low-calorie peach-flavored black teaand Prata® natural mineral water (negative control). Seventy-five bovine enamel specimens were distributed among the five types of beverages (n=15), according to a randomized complete block design. For the formation of erosive wear lesions, the specimens were immersed in 10 mL aqueous solution of hydrochloric acid 0.01 M for 2 min. Subsequently, the specimens were immersed in 20 mL of the beverages for 1 min, twice daily for 2 days at room temperature. In between, the specimens were kept in 20 mL of artificial saliva at 37ºC. The response variable was the quantitative enamel microhardness. ANOVA and Tukey's test showed highly significant differences (phydrochloric acid and beverages. The soft drink caused a significantly higher decrease in microhardness compared with the other beverages. The black tea caused a significantly higher reduction in microhardness than the mineral water, UHT milk and soymilk, but lower than the soft drink. Among the analyzed beverages, the soft drink and the black tea caused the most deleterious effects on dental enamel microhardness.

  8. Comparison of sulfuric and hydrochloric acids as catalysts in hydrolysis of Kappaphycus alvarezii (cottonii).

    Science.gov (United States)

    Meinita, Maria Dyah Nur; Hong, Yong-Ki; Jeong, Gwi-Taek

    2012-01-01

    In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and by-products. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 (°)C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.

  9. Multistage dilute acid leaching of a medium grade iron ore to super-concentrate

    Directory of Open Access Journals (Sweden)

    Adeleke A.A.

    2014-01-01

    Full Text Available The phosphorous laden Koton Karfe iron ore is a medium grade iron ore deposit in Nigeria that can be upgraded as a super-concentrate for use at the Aladja Steel Midrex plant. The 75 μm size sample fraction of the ore was preconcentrated with shaking table and leached in the oven at atmospheric pressure with dilute hydrochloric acid in single and multistage leaching sequences of H2O-HCl-H2O and HCl-H2O-H2O. The as-received, as-tabled and asleached samples were then subjected to X-ray fluorescence and microscopic analyses. The results obtained showed that the H2O-HCl-H2O route produced a higher grade concentrate that assayed 68.54% Fe indicating about 58% upgrade in iron content; while the phosphorus and sulphur contents were reduced by about 77 and 99.6% respectively. In addition, the silicon, manganese, and titanium contents were drastically reduced, while potassium was completely eliminated. The upgrade of iron content in the ore to 68.54% and the drastic reduction in phosphorous and sulphur contents has thus rendered the Koton Karfe iron ore suitable for use as a super concentrate for the Aladja steel plant direct reduction iron making process.

  10. Teaching Paleontology with an Acid-Leaching Facility.

    Science.gov (United States)

    Talent, John A.; And Others

    1987-01-01

    Described is an acid-leaching facility at Macquarie University in Australia for teaching paleontology. The facility is used for teaching both undergraduate and graduate students and for research by staff and graduate students. Drawings of the facility are included and courses are described. (Author/RH)

  11. Selective removal of chromium from sulphuric acid leach liquor of ...

    African Journals Online (AJOL)

    The selective removal of chromium, a trace impurity that degrades the whiteness of titanium(IV) oxide pigments, from sulphuric acid leach liquor of ilmenite, was investigated by solvent extraction with xylene solutions of trioctylamine. Important factors of commercial significance affecting the extraction operation have been ...

  12. Microabrasion using 18% hydrochloric acid and 37% phosphoric acid in various degrees of fluorosis - an in vivo comparision.

    Science.gov (United States)

    Sinha, Soumya; Vorse, Kiran Kumar; Noorani, Hina; Kumaraswamy, Shivprakash Pujari; Varma, Siddhartha; Surappaneni, Haragopal

    2013-01-01

    The aim of this study was to assess the efficacy of 18% hydrochloric acid and 37% phosphoric acid by an in vivo comparison. Sixty fluorotic permanent maxillary central incisors from 30 patients were divided into 3 categories. The teeth received 5 seconds (mild fluorosis), 20 seconds (moderate fluorosis) and 30 seconds (severe fluorosis) application of 18% hydrochloric acid on 11 and 37% phosphoric acid on 21. Standardized intraoral photographies were taken immediately before, after, and one month after treatment. Vinyl polysiloxane impression of the patient were made before and after the treatment. A scanning electron microscopic (SEM) evaluation was carried out on the models to judge the surface alterations. Wilcoxon and Mann-Whitney tests were used to verify the hypothesis. A statistically significant result was obtained in the reduction of white spot opacities, intensity of stains and the total area occupied by the stains in mild and moderate fluorosis teeth. Results of severe fluorosis had an unpredictable outcome. An SEM evaluation revealed good improvement in the surface texture of mild and moderate fluorosis teeth. Teeth with severe fluorosis showed only a slight improvement. A microabrasion procedure is effective for treating mild and moderate fluorosis cases.

  13. Cellulose acetate layer effect toward aluminium corrosion rate in hydrochloric acid media

    Science.gov (United States)

    Andarany, K. S.; Sagir, A.; Ahmad, A.; Deni, S. K.; Gunawan, W.

    2017-09-01

    Corrosion occurs due to the oxidation and reduction reactions between the material and its environment. The oxidation reaction defined as reactions that produce electrons and reduction is between two elements that bind the electrons. Corrosion cannot be inevitable in life both within the industry and household. Corrosion cannot eliminate but can be control. According to the voltaic table, Aluminum is a metal that easily corroded. This study attempts to characterize the type of corrosion by using a strong acid media (HCl). Experiment using a strong acid (HCl), at a low concentration that occurs is pitting corrosion, whereas at high concentrations that occurs is corrosion erosion. One of prevention method is by using a coating method. An efforts are made to slow the rate of corrosion is by coating the metal with “cellulose acetate” (CA). cellulose acetate consisted of cellulose powder dissolved in 99% acetic acid, and then applied to the aluminum metal. Soaking experiments using hydrochloric acid, cellulose acetate is able to slow down the corrosion rate of 47 479%.

  14. Leaching of basic oxygen furnace sludge with sulphuric acid

    Directory of Open Access Journals (Sweden)

    Andrea Miškufová

    2010-03-01

    Full Text Available In this study the hydrometallurgical processing of BOF sludge in the sulphuric acid solutions under atmospheric pressureand temperatures up to 100 °C is investigated on a laboratory scale. The influence of sulphuric acid concentration, temperature, timeand liquid to solid ratio (L:S on the leaching process was studied. The main aim of this study was to determine optimal conditions whenthe maximum amount of zinc passes into the solution.

  15. Effect of hypertonic saline treatment on the inflammatory response after hydrochloric acid-induced lung injury in pigs.

    Science.gov (United States)

    Holms, Carla Augusto; Otsuki, Denise Aya; Kahvegian, Marcia; Massoco, Cristina Oliveira; Fantoni, Denise Tabacchi; Gutierrez, Paulo Sampaio; Auler Junior, Jose Otavio Costa

    2015-08-01

    Hypertonic saline has been proposed to modulate the inflammatory cascade in certain experimental conditions, including pulmonary inflammation caused by inhaled gastric contents. The present study aimed to assess the potential anti-inflammatory effects of administering a single intravenous dose of 7.5% hypertonic saline in an experimental model of acute lung injury induced by hydrochloric acid. Thirty-two pigs were anesthetized and randomly allocated into the following four groups: Sham, which received anesthesia and were observed; HS, which received intravenous 7.5% hypertonic saline solution (4 ml/kg); acute lung injury, which were subjected to acute lung injury with intratracheal hydrochloric acid; and acute lung injury + hypertonic saline, which were subjected to acute lung injury with hydrochloric acid and treated with hypertonic saline. Hemodynamic and ventilatory parameters were recorded over four hours. Subsequently, bronchoalveolar lavage samples were collected at the end of the observation period to measure cytokine levels using an oxidative burst analysis, and lung tissue was collected for a histological analysis. Hydrochloric acid instillation caused marked changes in respiratory mechanics as well as blood gas and lung parenchyma parameters. Despite the absence of a significant difference between the acute lung injury and acute lung injury + hypertonic saline groups, the acute lung injury animals presented higher neutrophil and tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-8 levels in the bronchoalveolar lavage analysis. The histopathological analysis revealed pulmonary edema, congestion and alveolar collapse in both groups; however, the differences between groups were not significant. Despite the lower cytokine and neutrophil levels observed in the acute lung injury + hypertonic saline group, significant differences were not observed among the treated and non-treated groups. Hypertonic saline infusion after intratracheal hydrochloric

  16. Extraction of gold from hydrochloric acid solutions by Alamine 336 and Alkylaniline

    Directory of Open Access Journals (Sweden)

    Natalya Dolgova

    2013-09-01

    Full Text Available The extraction of gold with 336 Alamin and Alkylaniline from hydrochloric acid solutions was studied. Shown that Alamin extracts gold quantitatively in the field of acidity of the aqueuous phase pH=3,0 – СHCl=3,5 M when used as diluents of kerosene and higher carboxylic acids in admixture with paraffin. The time of quantitative extraction of gold: with Alamin – 3 minutes, with Alkylaniline – 5 minutes, regardless of the choice of diluent. The composition of the extracted complex and scheme of  gold extraction process with Alamin was proposed. Extraction of gold with 5%- Alamin-HCA-paraffin can be used for development of a combined extraction -  X-ray fluorescence technique for determination of gold because the resulting solids extracts meet the requirements imposed on emitters samples in X-ray fluorescence analysis. Calibration characteritstic is linear in the range of gold content in the samples emitters 0,006-0,17 wt%.

  17. Enhanced blood compatibility of metallocene polyethylene subjected to hydrochloric acid treatment for cardiovascular implants.

    Science.gov (United States)

    Jaganathan, Saravana Kumar; Mohandas, Hemanth; Sivakumar, Gunalan; Kasi, Palaniappan; Sudheer, Theertha; Avineri Veetil, Sruthi; Murugesan, Selvakumar; Supriyanto, Eko

    2014-01-01

    Blood compatibility of metallocene polyethylene (mPE) was investigated after modifying the surface using hydrochloric acid. Contact angle of the mPE exposed to HCl poses a decrease in its value which indicates increasing wettability and better blood compatibility. Surface of mPE analyzed by using FTIR revealed no significant changes in its functional groups after treatment. Furthermore, scanning electron microscope images supported the increasing wettability through the modifications like pit formations and etching on the acid rendered surface. To evaluate the effect of acid treatment on the coagulation cascade, prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured. Both PT and APTT were delayed significantly (P < 0.05) after 60 min exposure implying improved blood compatibility of the surfaces. Hemolysis assay of the treated surface showed a remarkable decrease in the percentage of lysis of red blood cells when compared with untreated surface. Moreover, platelet adhesion assay demonstrated that HCl exposed surfaces deter the attachment of platelets and thereby reduce the chances of activation of blood coagulation cascade. These results confirmed the enhanced blood compatibility of mPE after HCl exposure which can be utilized for cardiovascular implants like artificial vascular prostheses, implants, and various blood contacting devices.

  18. Empirical Modeling of Iron Oxide Dissolution in Sulphuric and Hydrochloric Acid

    Science.gov (United States)

    Hemmelmann, Jan C.; Xu, Hao; Krumm, Wolfgang

    2013-10-01

    A new approach is presented to an empirical modeling of chemical pickling processes, based on the activation energy of oxide dissolution in hydrochloric acid (HCl) and sulfuric acid (H2SO4). The model allows us to calculate pickling times as a function of definite parameters. The main oxide layers on hot-rolled materials are magnetite (Fe3O4), hematite (Fe2O3), and wustite (FeO). On the laboratory scale, the activation energy of each oxide has been determined. FeO is a metastable oxide and has been produced based on magnetite powder in a H2/H2O atmosphere. The oxide powders used for the experimental procedure have been analyzed by X-ray powder diffraction to insure the proper stoichiometry and composition. The model allows us to calculate the time of oxide dissolution based on the parameters temperature, acid concentration, and the composition of the oxide layer. Calculated values are verified by surface potential measurement on industrial oxide layers. The hot-rolled material used for verification is low carbon steel. A comparison between calculated pickling times and experimental data will be presented.

  19. Vanadium Extraction from Shale via Sulfuric Acid Baking and Leaching

    Science.gov (United States)

    Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

    2018-01-01

    Fluorides are widely used to improve vanadium extraction from shale in China. Sulfuric acid baking-leaching (SABL) was investigated as a means of recovering vanadium which does not require the use of fluorides and avoids the productions of harmful fluoride-containing wastewater. Various effective factors were systematically studied and the experimental results showed that 90.1% vanadium could be leached from the shale. On the basis of phase transformations and structural changes after baking the shale, a mechanism of vanadium extraction from shale via SABL was proposed. The mechanism can be described as: (1) sulfuric acid diffusion into particles; (2) the formation of concentrated sulfuric acid media in the particles after water evaporation; (3) hydroxyl groups in the muscovite were removed and transient state [SO4 2-] was generated; and (4) the metals in the muscovite were sulfated by active [SO4 2-] and the vanadium was released. Thermodynamics modeling confirmed this mechanism.

  20. Safety evaluation of a potential ablation agent-hydrochloric acid in the rabbits' model.

    Science.gov (United States)

    Yao, Wang; Gu, Yang-Kui; Wang, Jian; Gao, Fei; Liu, Wan-Li; Huang, Jin-Hua

    2014-10-01

    To evaluate the safety of a potential ablation agent-hydrochloric acid (HCl), which may apply to treat hepatocellular carcinoma (HCC). Eighty adult New Zealand rabbits were divided into five groups of equal size (n=16), i.e., untreated group, normal saline (NS) control group, 10% HCl group, 20% HCl group and 30% HCl group. Each group was divided into two subgroups: ten rabbits for two-week toxicology study at the time points of hours 0, 0.25, 0.5, 1, 3, 6 and days 2, 7, 14 and six rabbits for imaging and histopathology study at the time points of days 2, 7 and 14. In toxicology study we evaluated the safety of HCl from arterial blood gas status, hematology and hepatic and renal functions. In imaging and histopathology study, we observed the relationship between the sizes of lesion and the concentration of HCl, as well as extension of necrosis and concentration of HCl. In this study we also observed the microcosmic and macroscopic lesion that caused by HCl. In general condition, food, water consumption and body weight decreased notablely during the beginning of the experiment. In toxicology study, alanine aminotransferase, aspartate aminotransferase and lactic acid contents were higher in the 30% hydrochloric acid group than in other groups (P<0.005), all test items returned to normal on day 14. Imaging and histopathology study showed that 30% HCl caused larger lesion area than other HCl concentration and the necrosis that caused by HCl was complete. There was also a close relationship between the size of minor damaged area and HCl concentration. The 30% HCl caused larger minor damaged area than other HCl concentration. Because the damaged area was surrounded by a layer of fiber tissue, the lesion area became larger at days 7 and 14 time points. This study also demonstrated that the adjacent organs had no obvious damage, and all the damaged areas were limited in the liver. HCl is a safe ablation agent for local injection in the liver. HCl at a lower concentration is

  1. Surface chemical compositions and dispersity of starch nanocrystals formed by sulfuric and hydrochloric acid hydrolysis.

    Directory of Open Access Journals (Sweden)

    Benxi Wei

    Full Text Available Surface chemical compositions of starch nanocrystals (SNC prepared using sulfuric acid (H2SO4 and hydrochloric acid (HCl hydrolysis were analyzed by X-ray photoelectron spectroscopy (XPS and FT-IR. The results showed that carboxyl groups and sulfate esters were presented in SNC after hydrolysis with H2SO4, while no sulfate esters were detected in SNC during HCl-hydrolysis. TEM results showed that, compared to H2SO4-hydrolyzed sample, a wider size distribution of SNC prepared by HCl-hydrolysis were observed. Zeta-potentials were -23.1 and -5.02 mV for H2SO4- and HCl-hydrolyzed SNC suspensions at pH 6.5, respectively. Nevertheless, the zeta-potential values decreased to -32.3 and -10.2 mV as the dispersion pH was adjusted to 10.6. After placed 48 h at pH 10.6, zeta-potential increased to -24.1 mV for H2SO4-hydrolyzed SNC, while no change was detected for HCl-hydrolyzed one. The higher zeta-potential and relative small particle distribution of SNC caused more stable suspensions compared to HCl-hydrolyzed sample.

  2. Study on tea leaves extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

    Science.gov (United States)

    Hamdan, A. B.; Suryanto; Haider, F. I.

    2018-01-01

    Corrosion inhibitor from extraction of plant has been considered as the most preferable and most chosen technique to prevent corrosion of metal in acidic medium because of the environmental friendly factor. In this study, black tea leaves extraction was tested as corrosion inhibitor for mild steel in 0.1M of hydrochloric acid (HCl) with the absence and presence of corrosion inhibitor. The efficiency and effectiveness of black tea as corrosion inhibitor was tested by using corrosion weight loss measurement experiment was carried out with varies parameters which with different concentration of black tea extract solution. The extraction of black tea solution was done by using aqueous solvent method. The FT-IR result shows that black tea extract containing compounds such as catechin, caffeine and tannins that act as anti-corrosive reagents and responsible to enhance the effectiveness of black tea extract as corrosion inhibitor by forming the hydrophobic thin film through absorption process. As a result of weight loss measurement, it shows that loss in weight of mild steel reduces as the concentration of inhibitor increases. The surface analysis was done on the mild steel samples by using SEM.

  3. A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

    Science.gov (United States)

    Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

    2015-11-05

    Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Highly improved synthesis of gold nanobipyramids by tuning the concentration of hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Ying; Zhu, Jian; Li, Jianjun; Zhao, Junwu, E-mail: nanoptzhao@163.com [Xi’an Jiaotong University, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology (China)

    2016-07-15

    Fabrication of gold nanobipyramids (Au BPs) has attracted great attention because they exhibit more advantageous plasmonic properties. In this study, Au BPs were synthesized by the well-known seeded growth in the presence of hydrochloric acid (HCl). The effects of the ingredients, including HCl, silver nitrate (AgNO{sub 3}), l-Ascorbic acid (AA), and seeds on the structure and yield of the Au BPs were systemically investigated. The results showed that the abundant HCl could improve the yield of Au BPs and decrease the longitudinal surface plasmon resonance wavelength. Under the circumstance of higher concentration of AA and AgNO{sub 3}, more byproducts were resulted. In addition, the effect of HCl under different ratios of seed solution to AA has also been studied. The results showed that the yield was less sensitive to HCl when the amount of seed solution was small. If substantial AA was added to the system, then abundant HCl should be introduced correspondingly to improve the yield of Au BPs.

  5. Surface chemical compositions and dispersity of starch nanocrystals formed by sulfuric and hydrochloric acid hydrolysis.

    Science.gov (United States)

    Wei, Benxi; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2014-01-01

    Surface chemical compositions of starch nanocrystals (SNC) prepared using sulfuric acid (H2SO4) and hydrochloric acid (HCl) hydrolysis were analyzed by X-ray photoelectron spectroscopy (XPS) and FT-IR. The results showed that carboxyl groups and sulfate esters were presented in SNC after hydrolysis with H2SO4, while no sulfate esters were detected in SNC during HCl-hydrolysis. TEM results showed that, compared to H2SO4-hydrolyzed sample, a wider size distribution of SNC prepared by HCl-hydrolysis were observed. Zeta-potentials were -23.1 and -5.02 mV for H2SO4- and HCl-hydrolyzed SNC suspensions at pH 6.5, respectively. Nevertheless, the zeta-potential values decreased to -32.3 and -10.2 mV as the dispersion pH was adjusted to 10.6. After placed 48 h at pH 10.6, zeta-potential increased to -24.1 mV for H2SO4-hydrolyzed SNC, while no change was detected for HCl-hydrolyzed one. The higher zeta-potential and relative small particle distribution of SNC caused more stable suspensions compared to HCl-hydrolyzed sample.

  6. Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: quasi-elastic light scattering studies.

    Science.gov (United States)

    Guterman, L R; Falzone, J; Wilson, G E

    1986-05-01

    The effects of hydrochloric acid on mixed gels of aluminum and magnesium hydroxide and on magaldrate have been examined using quasi-elastic light scattering. Particles of magaldrate and mixed gels behave differently. The magaldrate particles initially decrease in size in response to increasing amounts of hydrochloric acid up to that sufficient to neutralize all the magnesium hydroxide present, then increase in size to approximately 2 microns. The composition of the mixed gels appears to be particularly important in determining the reaction with limited amounts of acid. For these particles, which are thought to consist of a magnesium hydroxide core surrounded by an aluminum hydroxide sheath, slow erosion of the aluminum hydroxide was apparently followed by complete disintegration of the particles. Particles which remain grow in size to approximately 3 microns.

  7. Impact of α-amylase combined with hydrochloric acid hydrolysis on structure and digestion of waxy rice starch.

    Science.gov (United States)

    Li, Hongyan; Zhu, Yanqiao; Jiao, Aiquan; Zhao, Jianwei; Chen, Xiaoming; Wei, Benxi; Hu, Xiuting; Wu, Chunsen; Jin, Zhengyu; Tian, Yaoqi

    2013-04-01

    The structure and in vitro digestibility of native waxy rice starch by the combined hydrolysis of α-amylase and hydrochloric acid were investigated in this study. The combined hydrolysis technique generated higher hydrolysis rate and extent than the enzymatic hydrolysis. The granular appearance and chromatograph profile demonstrated that α-amylase and hydrochloric acid exhibited different patterns of hydrolysis. The rise in the ratio of absorbance 1047/1022cm(-1), the melting temperature range (Tc-To), and the melting enthalpy (ΔH) were observed during the combined hydrolysis. These results suggest that α-amylase simultaneously cleaves the amorphous and crystalline regions, whereas the amorphous regions of starch granules are preferentially hydrolyzed during the acid hydrolysis. Furthermore, the combined hydrolysis increased rapidly digestible starch (RDS) while decreased slowly digestible starch (SDS) and resistant starch (RS), indicating that the hydrolysis mode affected the digestion property of native waxy rice starch. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Comparative studies on acid leaching of zinc waste materials

    Science.gov (United States)

    Rudnik, Ewa; Włoch, Grzegorz; Szatan, Leszek

    2017-11-01

    Three industrial waste materials were characterized in terms of their elemental and phase compositions, leaching behaviour in 10% sulfuric acid solution as well as leaching thermal effects. Slag from melting of mixed metallic scrap contained about 50% Zn and 10% Pb. It consisted mainly of various oxides and oxy-chlorides of metals. Zinc spray metallizing dust contained about 77% Zn in form of zinc and/or zinc-iron oxides, zinc metal and Zn-Fe intermetallic. Zinc ash from hot dip galvanizing was a mixture of zinc oxide, metallic zinc and zinc hydroxide chloride and contained about 80% Zn. Dissolution efficiency of zinc from the first material was 80% (independently on the solid to liquid ratio, 50–150 kg/m3), while decrease of the efficacy from 80% to 60% with increased solid to liquid ratio for the two remaining materials was observed. Both increase in the temperature (20 °C to 35 °C) and agitation rate (300 rpm to 900 rpm) did not improve seriously the leaching results. In all cases, transfer of zinc ions to the leachate was accompanied by different levels of solution contamination, depending on the type of the waste. Leaching of the materials was exothermic with the similar reaction heats for two high oxide-type products (slag, zinc ash) and higher values for the spray metallizing dust.

  9. A hydrometallurgical process for the recovery of terbium from fluorescent lamps: Experimental design, optimization of acid leaching process and process analysis.

    Science.gov (United States)

    Innocenzi, Valentina; Ippolito, Nicolò Maria; De Michelis, Ida; Medici, Franco; Vegliò, Francesco

    2016-12-15

    Terbium and rare earths recovery from fluorescent powders of exhausted lamps by acid leaching with hydrochloric acid was the objective of this study. In order to investigate the factors affecting leaching a series of experiments was performed in according to a full factorial plan with four variables and two levels (4 2 ). The factors studied were temperature, concentration of acid, pulp density and leaching time. Experimental conditions of terbium dissolution were optimized by statistical analysis. The results showed that temperature and pulp density were significant with a positive and negative effect, respectively. The empirical mathematical model deducted by experimental data demonstrated that terbium content was completely dissolved under the following conditions: 90 °C, 2 M hydrochloric acid and 5% of pulp density; while when the pulp density was 15% an extraction of 83% could be obtained at 90 °C and 5 M hydrochloric acid. Finally a flow sheet for the recovery of rare earth elements was proposed. The process was tested and simulated by commercial software for the chemical processes. The mass balance of the process was calculated: from 1 ton of initial powder it was possible to obtain around 160 kg of a concentrate of rare earths having a purity of 99%. The main rare earths elements in the final product was yttrium oxide (86.43%) following by cerium oxide (4.11%), lanthanum oxide (3.18%), europium oxide (3.08%) and terbium oxide (2.20%). The estimated total recovery of the rare earths elements was around 70% for yttrium and europium and 80% for the other rare earths. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The thermal, rheological and structural properties of cassava starch granules modified with hydrochloric acid at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Beninca, Cleoci; Colman, Tiago Andre Denck [State University of Ponta Grossa - UEPG, Av. Carlos Cavalcanti, 4748, ZIP 84030-900, Ponta Grossa, PR (Brazil); Lacerda, Luiz Gustavo; Filho, Marco Aurelio Silva Carvalho [Positivo University, Curitiba, PR (Brazil); Bannach, Gilbert [Paulista State University - UNESP, Bauru, SP (Brazil); Schnitzler, Egon, E-mail: egons@uepg.br [State University of Ponta Grossa - UEPG, Av. Carlos Cavalcanti, 4748, ZIP 84030-900, Ponta Grossa, PR (Brazil)

    2013-01-20

    Highlights: Black-Right-Pointing-Pointer Untreated cassava starch was modified with standard hydrochloric acid at 20 and 50 Degree-Sign C by 8 h. Black-Right-Pointing-Pointer DSC curves allowed to verify increase in the gelatinization enthalpy in agreement with high temperature. Black-Right-Pointing-Pointer Pasting properties of the studied starches were inversely proportional to the acid treatment and increased temperature. Black-Right-Pointing-Pointer The morphology of granules as well as average size and average roughness were calculated by NC-AFM. - Abstract: Starch is arguably one of the most actively investigated biopolymer in the world. In this study, the native (untreated) cassava starch granules (Manihot esculenta, Crantz) were hydrolyzed by standard hydrochloric acid solution at different temperatures (30 Degree-Sign C and 50 Degree-Sign C) and the hydrolytic transformations were investigated by the following techniques: simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), as well as non-contact atomic force microscopy (NC-AFM), X-ray diffraction (XRD) powder patterns, and rapid viscoamylographic analysis (RVA). After the treatment with hydrochloric acid at different temperatures, the thermal stability, a gradual loss of pasting properties (viscosity), alterations in the gelatinization enthalpy ({Delta}H{sub gel}), were observed. The use of NC-AFM and XRD allowed the observation of the surface morphology and topography of the starch granules and changes in crystallinity of the granules, respectively.

  11. Inhibition of the corrosion of mild steel in hydrochloric acid by isatin and isatin glycine

    Directory of Open Access Journals (Sweden)

    B.I. Ita

    2006-12-01

    Full Text Available The inhibition of corrosion of mild steel in hydrochloric acid by isatin glycine (ING and isatin (IN at 30-60 oC and concentrations of 0.0001 M to 0.0005 M was studied via weight loss method. At the highest inhibitor concentration studied ING exhibited inhibition efficiency of 87% while IN exhibited 84% at 60 oC. A chemical adsorption mechanism was proposed on the basis of the temperature effect and obtained average activation energy values of 143.9 kJ/mol for ING and 118.5 kJ/mol for IN. The two inhibitors were confirmed to obey the Langmuir adsorption isotherm equation at the concentrations studied. Also a first-order type of mechanism was proposed from the kinetic treatment of the result. The difference in the inhibitory properties of the inhibitors was explained in terms of the difference in their molecular structures and solubility rather than difference in molecular weights alone.

  12. Studies on the inhibition of mild steel corrosion in hydrochloric acid solution by atenolol drug

    Directory of Open Access Journals (Sweden)

    G. Karthik

    2016-06-01

    Full Text Available The inhibition performance of atenolol on mild steel in 1 M hydrochloric acid solution was studied by weight loss and electrochemical methods. The results show the inhibition efficiency was found to increase with increasing the concentration of the inhibitor from 50 to 300 ppm. The maximum inhibition efficiency 93.8% was observed in the presence of 300 ppm inhibitor (in case of potentiodynamic polarization. The inhibition action of atenolol was explained in terms of adsorption on the mild steel surface. The adsorption process follows Langmuir isotherm via physical adsorption. Electrochemical Impedance spectroscopic technique (EIS exhibits one capacitive loop indicating that, the corrosion reaction is controlled by charge transfer process. Polarization measurements showed that the inhibitor is of a mixed type. The results obtained from the different methods are in good agreement. The surface morphologies of mild steel were examined by Fourier-transform infrared (FT-IR spectroscopy, scanning electron microscope (SEM. Further, the computational calculations are performed to find a relation between their electronic and structural properties.

  13. Effect of foods and drinks on primary tooth enamel after erosive challenge with hydrochloric acid.

    Science.gov (United States)

    Mesquita-Guimarães, Késsia Suênia Fidelis de; Scatena, Camila; Borsatto, Maria Cristina; Rodrigues-Júnior, Antonio Luiz; Serra, Mônica Campos

    2015-01-01

    The aim of this study was to evaluate the effect of industrialised foods and drinks on primary tooth enamel previously eroded with hydrochloric acid (HCl). The crowns of one hundred two specimens were subjected to an erosive challenge with HCl and randomly divided into six groups (n = 17): Chocolate Milk (Toddynho® - Pepsico) - negative control; Petit Suisse Yogurt (Danoninho® - Danone); Strawberry Yogurt (Vigor); Apple puree (Nestlé); Fermented Milk (Yakult® - Yakult); and Home Squeezed Style Orange Juice (del Valle) - positive control. The 28-day immersion cycles for the test products were performed twice daily and were interspersed with exposure of the test substrate to artificial saliva. Measurements of enamel surface microhardness (SMH) were performed initially, after immersion in HCl and at 7, 14, 21 and 28 days of experimentation. A two-way ANOVA, according to a split-plot design, followed by the sum of squares decomposition and Tukey's test, revealed a significant effect for the interaction between Foods and Drinks and Length of Exposure (p < 0.00001). Orange juice resulted in greater mineral loss of enamel after 28 days. None of the test products was associated with recovery of tooth enamel microhardness.

  14. Variation of structures of ingredients of desiccated coconut during hydrolysis by hydrochloric acid at low temperature

    Directory of Open Access Journals (Sweden)

    Jian XIONG

    2017-10-01

    Full Text Available Abstract Owing to the high content of lignocellulose, desiccated coconut become a healthy material for dietary fiber supplementation. In this study, the changes in solubility of the fibers of desiccated coconut were evaluated. The changes of the pHs and weight losses were studied. Furthermore, variations of the ingredient structures of desiccated coconut by hydrolysis by hydrochloric acid were characterized by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD and scanning electron microscopy (SEM. After hydrolysis 30 s, the pHs of all systems increased, while six hours later, the pH of only system with initial pH = 1.00 decreased. The decline of pH only existed in hydrolysis systems with initial pH = 1.00, there is no relevant with the quantities of desiccated coconut. The lower initial pH of hydrolysis system was, the less the intrinsic viscosity of the desiccated coconut after hydrolysis was, the small the crystallinity was. After hydrolysis, the microstructure of the desiccated coconut become looser, and the secondary structure of the coconut protein became more stable and ordered. The results suggest that the hydrolysis of desiccated coconut mainly occurred in the branched chain and the non-crystalline region of lignocellulose, which transforms some insoluble dietary fiber into soluble dietary fiber. This improves the nutritional value of desiccated coconut.

  15. Establishment of hydrochloric acid/lipopolysaccharide-induced pelvic inflammatory disease model.

    Science.gov (United States)

    Oh, Yeonsu; Lee, Jaehun; Kim, Hyeon-Cheol; Hahn, Tae-Wook; Yoon, Byung-Il; Han, Jeong-Hee; Kwon, Yong-Soo; Park, Joung Jun; Koo, Deog-Bon; Rhee, Ki-Jong; Jung, Bae Dong

    2016-09-30

    Pelvic inflammatory disease (PID), which is one of the most problematic complications experienced by women with sexually transmitted diseases, frequently causes secondary infections after reproductive abnormalities in veterinary animals. Although the uterus is self-protective, it becomes fragile during periods or pregnancy. To investigate PID, bacteria or lipopolysaccharide (LPS) extracted from gram negative bacteria has been used to induce the disease in several animal models. However, when LPS is applied to the peritoneum, it often causes systemic sepsis leading to death and the PID was not consistently demonstrated. Hydrochloric acid (HCl) has been used to induce inflammation in the lungs and stomach but not tested for reproductive organs. In this study, we developed a PID model in mice by HCl and LPS sequential intracervical (i.c.) administration. The proinflammatory cytokines, interleukin (IL)-1β, IL-6 and tumor necrosis factor-α, were detected in the mouse uterus by western blot analysis and cytokine enzyme-linked immunosorbent assay after HCl (25 mg/kg) administration i.c. followed by four LPS (50 mg/kg) treatments. Moreover, mice exhibited increased infiltration of neutrophils in the endometrium and epithelial layer. These results suggest that ic co-administration of HCl and LPS induces PID in mice. This new model may provide a consistent and reproducible PID model for future research.

  16. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

    Science.gov (United States)

    Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

    2016-11-05

    Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Effect of foods and drinks on primary tooth enamel after erosive challenge with hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Késsia Suênia Fidelis de MESQUITA-GUIMARÃES

    2015-01-01

    Full Text Available The aim of this study was to evaluate the effect of industrialised foods and drinks on primary tooth enamel previously eroded with hydrochloric acid (HCl. The crowns of one hundred two specimens were subjected to an erosive challenge with HCl and randomly divided into six groups (n = 17: Chocolate Milk (Toddynho® - Pepsico - negative control; Petit Suisse Yogurt (Danoninho® - Danone; Strawberry Yogurt (Vigor; Apple puree (Nestlé; Fermented Milk (Yakult® - Yakult; and Home Squeezed Style Orange Juice (del Valle - positive control. The 28-day immersion cycles for the test products were performed twice daily and were interspersed with exposure of the test substrate to artificial saliva. Measurements of enamel surface microhardness (SMH were performed initially, after immersion in HCl and at 7, 14, 21 and 28 days of experimentation. A two-way ANOVA, according to a split-plot design, followed by the sum of squares decomposition and Tukey’s test, revealed a significant effect for the interaction between Foods and Drinks and Length of Exposure (p < 0.00001. Orange juice resulted in greater mineral loss of enamel after 28 days. None of the test products was associated with recovery of tooth enamel microhardness.

  18. Corrosion Behavior of Ni3(Si,Ti + 2Mo in Hydrochloric Acid Solution

    Directory of Open Access Journals (Sweden)

    Gadang Priyotomo

    2013-10-01

    Full Text Available The corrosion behavior of Ni3(Si,Ti + 2Mo intermetallic compound (L12 and (L12 + Niss mixture region has been investigated using an immersion test, polarization method and surface analytical method (scanning electron microscope and energy-dispersive X-Ray spectrometry in 0.5 kmol/m3 hydrochloric acid (HCl solution at 303 K.  In addition, the results obtained were compared to those of the L12 single-phase Ni3(Si,Ti intermetallic compound and C 276 alloy.  It was found that Ni3(Si,Ti + 2Mo had the preferential dissolution of L12 with a lower Mo concentration compared to (L12 + Niss mixture region.  From the immersion test and polarization curves, Ni3(Si,Ti + 2Mo and C276 showed the lowest corrosion resistance and the highest corrosion resistance in the solution, respectively.  From this work, It implied that unlike C276, Ni3(Si,Ti +2Mo intermetallic compound was difficult to form a stable passive film in HCl solution as well as Ni3(Si,Ti in the same solution.

  19. Evaluation tissue dissolution property of 2.5 % Sodium Hypochlorite Prepared by Hydrochloric Acid and Sodium Bicarbonate: An in vitro

    OpenAIRE

    Hamid Razavian; Mohsen Hasheminia; Hazhir Yousefshahi; Rastin Sadeghian; Asana Valli

    2016-01-01

    Successful endodontic treatment requires chemical preparation in addition to mechanical preparation. The most common material for chemical preparations is sodium hypochlorite. One way to reduce the effects of pH adjustment is the use of sodium hypochlorite. The present paper was conducted to examine the effect of dilution with hydrochloric acid and sodium bicarbonate and reduce pH on ability of tissue solubility of sodium hypochlorite. The present study was conducted in vitro on b...

  20. Evaluation tissue dissolution property of 2.5 % Sodium Hypochlorite Prepared by Hydrochloric Acid and Sodium Bicarbonate: An in vitro

    Directory of Open Access Journals (Sweden)

    Hamid Razavian

    2016-08-01

    Full Text Available Successful endodontic treatment requires chemical preparation in addition to mechanical preparation. The most common material for chemical preparations is sodium hypochlorite. One way to reduce the effects of pH adjustment is the use of sodium hypochlorite. The present paper was conducted to examine the effect of dilution with hydrochloric acid and sodium bicarbonate and reduce pH on ability of tissue solubility of sodium hypochlorite. The present study was conducted in vitro on bovine muscle tissue. Ability of tissue solubility was conducted in four groups respectively with active ingredient including 1 sodium hypochlorite diluted with distilled water 2 sodium hypochlorite diluted with sodium bicarbonate 3 sodium hypochlorite diluted with hydrochloric acid and finally 4 distilled water (control group. Each sample was firstly weighed and then placed in contact with 10 m/L solution for 60 minutes (five 12 -minute intervals. The sample was weighted every five minutes and solution was renewed. The results were analyzed using SPSS-21 Software based on variance analysis, Tukey and T-test (α=0.05. The findings showed that there was significant difference between first, second and third groups in terms of ability of tissue solubility. However, the tissue solubility in second and third groups was lower than first group and it was similar in second and third groups (P Value <0.001. Reduction of sodium bicarbonate PH using sodium hypochlorite and hydrochloric acid reduces ability of tissue solubility in sodium hypochlorite.

  1. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Terry, Brandon C., E-mail: terry13@purdue.edu [School of Aeronautics and Astronautics, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States); Sippel, Travis R. [Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011 (United States); Pfeil, Mark A. [School of Aeronautics and Astronautics, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States); Gunduz, I.Emre; Son, Steven F. [School of Mechanical Engineering, Purdue University, Zucrow Laboratories, 500 Allison Rd, West Lafayette, IN 47907 (United States)

    2016-11-05

    Highlights: • Al-Li alloy propellant has increased ideal specific impulse over neat aluminum. • Al-Li alloy propellant has a near complete reduction in HCl acid formation. • Reduction in HCl was verified with wet bomb experiments and DSC/TGA-MS/FTIR. - Abstract: Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (I{sub SP}). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal I{sub SP} by ∼7 s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5 ± 4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.

  2. Praeruptorin D and E attenuate lipopolysaccharide/hydrochloric acid induced acute lung injury in mice.

    Science.gov (United States)

    Yu, Peng-Jiu; Li, Jing-Rong; Zhu, Zheng-Guang; Kong, Huan-Yu; Jin, Hong; Zhang, Jun-Yan; Tian, Yuan-Xin; Li, Zhong-Huang; Wu, Xiao-Yun; Zhang, Jia-Jie; Wu, Shu-Guang

    2013-06-15

    Acute lung injury is a life-threatening syndrome characterized by overwhelming lung inflammation and increased microvascular permeability, which causes a high mortality rate worldwide. The dry root of Peucedanum praeruptorum Dunn has been long used to treat respiratory diseases in China. In the present study, Praeruptorin A, C, D and E (PA, PC, PD and PE), four pyranocoumarins extracted from this herb, have been investigated for the pharmacological effects in experimental lung injury mouse models. In lipopolysaccharide (LPS) challenged mice, PA and PC did not show protective effect against lung injury at the dose of 80 mg/kg. However, PD and PE significantly inhibited the infiltration of activated polymorphonuclear leukocytes (PMNs) and decreased the levels of TNF-α and IL-6 in bronchoalveolar lavage fluid at the same dose. There was no statistically significant difference between PD and PE group. Further study demonstrated that PD and PE suppressed protein extravasations in bronchoalveolar lavage fluid, attenuated myeloperoxidase (MPO) activity and the pathological changes in the lung. Both PD and PE suppressed LPS induced Nuclear Factor-kappa B (NF-κB) pathway activation in the lung by decreasing the cytoplasmic loss of Inhibitor κB-α (IκB-α) protein and inhibiting the translocation of p65 from cytoplasm to nucleus. We also extended our study to acid-induced acute lung injury and found that these two compounds protected mice from hydrochloric acid (HCl)-induced lung injury by inhibiting PMNs influx, IL-6 release and protein exudation. Taken together, these results suggested that PD and PE might be useful in the therapy of lung injury. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Predictive QSPR analysis of corrosion inhibitors for super 13% Cr steel in hydrochloric acid

    Directory of Open Access Journals (Sweden)

    S. P. Cardoso

    2007-12-01

    Full Text Available An experimental and theoretical study on the inhibition corrosion efficiencies of twenty three compounds in hydrochloric acid (15% w/v on 13% Cr modified stainless steel (martensitic has been carried out. This inhibitor set includes amines, thiourea derivatives and acetylenic alcohols. Experimental weight losses at 60ºC were correlated with group and quantum AM1 descriptors obtained from QSPR analysis. Such data, for a large set of molecules, offer a unique opportunity for searching for correlations between inhibition corrosion efficiency and molecular properties. Calculations based on three different statistical methodologies were carried out. The first method, using calibration procedures, employs an ordinary least squares (OLS methodology with a simple descriptor selection based on R² values. From this procedure, we obtained a model, Y15, having a R² value of 0,979 and a Q² value of 0.786. The second method employs a descriptor selection based on the second-order cross-validation OLS procedure (SOCV-OLS. In this process, the variables are chosen according to their ability to predict molecular inhibition efficiencies. The best model obtained using this methodology, Q5, had R² and Q² values of 0.859 and 0.785, respectively. The third method, based on regular partial least squares (PLS, resulted in R² and Q² values of 0.859 and 0.754, respectively. All calculations were carried out for the weight isoesteric Langmuir adsorption function (WILA function, ln(thetaM/(1-theta or ln Kads. A careful comparison between the calibration and the cross-validation descriptor selection indicated that they had very few descriptors in common. This article presents some key equations and the most relevant descriptors. We are unaware of any similar QSPR study on super 13% Cr stainless steel in the literature.

  4. Copper-promoted cementation of antimony in hydrochloric acid system: A green protocol.

    Science.gov (United States)

    Wu, Lian-Kui; Li, Ying-Ying; Cao, Hua-Zhen; Zheng, Guo-Qu

    2015-12-15

    A new method of recovering antimony in hydrochloric acid system by cementation with copper powder was proposed and carried out at laboratory scale. Thermodynamic analysis and cyclic voltammetry test were conducted to study the cementation process. This is a novel antimony removal technology and quite meets the requirements of green chemistry. The main cement product Cu2Sb is a promising anodic material for lithium and sodium ion battery. And nearly all consumed copper powder are transformed into CuCl which is an important industrial material. The effect of reaction temperature, stoichiometric ratio of Cu to Sb(III), stirring rate and concentration of HCl on the cementation efficiency of antimony were investigated in detail. Optimized cementation condition is obtained at 60 °C for 120 min and stirring rate of 600 rpm with Cu/Sb(III) stoichiometric ratio of 6 in 3 mol L(-1) HCl. At this time, nearly all antimony can be removed by copper powder and the cementation efficiency is over 99%. The structure and morphologies of the cement products were characterized by X-ray diffraction and scanning electron microscopy, respectively. Results show that the reaction temperature has little influence on the morphology of the cement products which consist of particles with various sizes. The activation energy of the cementation antimony on copper is 37.75 kJ mol(-1), indicating a chemically controlled step. Inductively coupled plasma mass spectrometry results show that no stibine generates during the cementation process. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Electrical response of the Summit-Greenland ice core to ammonium, sulphuric acid, and hydrochloric acid

    Science.gov (United States)

    Moore, John C.; Wolff, Eric W.; Clausen, Henrik B.; Hammer, Claus U.; Legrand, Michel R.; Fuhrer, Katrin

    1994-04-01

    Electrical and chemical analysis of the Greenland Ice Core Project (GRIP) ice core from Summit in central Greenland confirms that the ECM current is controlled solely by acids in the ice, though there could be different responses for different acids. The dielectric conductivity is dependent on strong acid, on sea salt chloride, and also on ammonium concentrations in the ice. The response to NH4(+) is similar to that of sea salt chloride, as they both conduct only at AC frequencies, but NH4(+) is approximately twice as conductive per mole. The response to the strong acids shows results consistent with earlier work, with similar responses throughout the length of the core. It seems as if all the thousands of electrical peaks in the GRIP core may be explained by the response to just three chemical species: acidity, ammonium salts, and a third component which is probably chloride.

  6. Characterization of Polyamide 66 membranes prepared by phase inversion using formic acid and hydrochloric acid such as solvents

    Directory of Open Access Journals (Sweden)

    Patrícia Poletto

    2011-12-01

    Full Text Available The membranes properties prepared from water/formic acid (FA/ polyamide 66 (PA66 and water/hydrochloric acid (HCl/polyamide 66 (PA 66 systems has been studied. The different solvents interact distinctly with the polymer, affecting the membrane morphology. The asymmetric structure of the membranes showed a dense top layer and a porous sublayer. The membranes M-HCl prepared from HCl/PA 66 system showed a larger dense layer (around 23 μm in compared to those prepared from FA/PA 66 system (M-FA (around 10 μm. The membrane morphology was a determinant factor in results of water absorption, porosity and pure water flux. The lower thickness of dense layer in M-FA membranes resulted in a higher water absorption and, consequently, porosity, approximately 50%, compared with M-HCl membranes, approximately 15%. The same trend was observed to permeate flux, the lower thickness of dense layer higher pure water flux.

  7. Influence of chalcopyrite structure on their leaching by sodium nitrate in sulphuric acid

    Directory of Open Access Journals (Sweden)

    Miroslav Sokić

    2014-03-01

    Full Text Available During the chalcopyrite leaching by sodium nitrate and sulfuric acid solution, leaching rate decreases with increasing the time and a part of chalcopyrite mineral grains remains in the leach residue. In chalcopyrite concentrate, 95.5 % of chalcopyrite mineral occurs as in liberated grains, and the rest is in association with gangue minerals, which is very favorably from the aspect of hydrometallurgical treatment. Complex forms, like impregnations and complex intergrowths, do not exist. After experiments carried out, leaching of copper achieved 84 % at temperature 80 o C and time 240 min. In the all leach residues, 97 % chalcopyrite mineral grains occur as liberated with highly corroded surfaces. Therefore, the structural assembly of chalcopyrite grains is favorable and no reason to reduce the leaching rate in the final stage of reaction. Reason for this is elemental sulfur, which was formed during the reaction, precipitated at the particle surfaces, and slowed down the leaching rate in the final stage of leaching process.

  8. Thermal decomposition of ethylenediaminetetraacetic acid in the presence of 1,2-phenylenediamine and hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jingwen [Yancheng Institute of Technology, Yancheng (China); Gao, Jinhao [Nanjing Univ., Nanjing (China). Coordination Chemistry Institute. State Key Lab. of Coordination Chemistry; Wang, Xiaoyong [Nanjing Univ., Nanjing (China). School of Life Science. State Key Lab. of Pharmaceutical Biotechnology]. E-mail: boxwxy@nju.edu.cn

    2006-09-15

    Based on the reaction products of ethylenediaminetetraacetic acid (EDTA) with 1,2- phenylenediamine (o-PDA), a novel thermal decomposition pathway of EDTA is proposed. The strong acidic medium and the presence of o-PDA facilitate the decomposition of EDTA as evidenced by the relatively lower reaction temperature. In addition to the steps described in literatures, rearrangement process is involved in the decomposition reaction. The rearranged intermediates condense with o-PDA, forming an unexpected biologically active compound 2,2,4- trimethyl-3H-5-hydro-1,5-benzodiazepine, thus provides the possibility to explore an alternative decomposition mechanism for this widely used chelator. (author)

  9. The Effect of Fulvic Acid on the Leaching of a Weathered Rare-Earth Ore

    Science.gov (United States)

    Luo, Xian-ping; Feng, Bo; Wang, Peng-cheng; Zhou, He-peng; Chen, Xiao-ming

    2015-12-01

    The effect of fulvic acid on the leaching of a weathered crust elution-deposited rare-earth ore, using ammonium sulfate as lixiviant, has been investigated. The results show that fulvic acid can enhance the leaching process effectively. With the addition of fulvic acid to the lixiviant at a concentration of 0.1 wt pct, the leaching extraction of rare-earth elements increased by 8.38 pct and the ammonium sulfate concentration decreased by 25 wt pct. Fulvic acid promotes the leaching process. It also reacts with rare-earth ions, forms soluble complexes, reduces the activity of the leached rare-earth ions, and increases the concentration difference of ion diffusion. These results highlight a new approach for making the leaching process of low-grade weathered crust elution-deposited rare-earth ore more efficient and also for lowering the lixiviant consumption.

  10. The effects of pharmaceutically active compound doxycycline on the corrosion of mild steel in hydrochloric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Sudhish Kumar [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh (India); Quraishi, M.A. [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh (India)], E-mail: maquraishi.apc@itbhu.ac.in

    2010-02-15

    Corrosion inhibition of mild steel in hydrochloric acid solution by doxycycline has been studied by weight loss measurements, polarization resistance, Tafel polarization and electrochemical impedance spectroscopy. The inhibitor showed more than 95% inhibition efficiency at optimum concentration 9.02 x 10{sup -4} M. Potentiodynamic polarization suggests that it is a mixed type of inhibitor. Electrochemical impedance spectroscopy was used to investigate the mechanism of corrosion inhibition. Thermodynamic parameters were calculated to investigate mechanism of inhibition. The compound follows Langmuir adsorption isotherm. AFM studies of mild steel surface with and without inhibitor were performed and calculated roughness also supported the inhibition data.

  11. Hydrochloric acid-enhanced radiofrequency ablation for treating a large hepatocellular carcinoma with spontaneous rapture: a case report.

    Science.gov (United States)

    Huang, Jin-Hua; Morelli, John N; Ai, Fei; Zou, Ru-Hai; Gu, Yang-Kui; Gao, Fei; Zhang, Tian-Qi; Yao, Wang; Jiang, Xiong-Ying; Zhang, Yan-Yang

    2017-01-07

    A ruptured hepatocellular carcinoma (HCC) is often fatal. In addition to surgery and transarterial embolization, radiofrequency ablation (RFA) might be another option for treating a ruptured HCC. Unfortunately, conventional RFA has a limited ablation zone; as such, it is rarely used to treat ruptured tumors. This case was a 60-year-old man who had a large, ruptured HCC in which hydrochloric acid (HCl)-enhanced RFA successfully controlled the bleeding and made the tumor completely necrotic. Considering the effectiveness of HCl-enhanced RFA in achieving hemostasis and tumor ablation, it might be a new option for treating large, ruptured HCCs.

  12. Enhanced Corrosion Resistance of Carbon Steel in Hydrochloric Acid Solution by Eriobotrya Japonica Thunb. Leaf Extract: Electrochemical Study.

    Science.gov (United States)

    Yang, Wenjing; Wang, Qihui; Xu, Ke; Yin, Yanjun; Bao, Hebin; Li, Xueming; Niu, Lidan; Chen, Shiqi

    2017-08-16

    The biodegradable inhibitors, which could effectively reduce the rate of corrosion of carbon steel, were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The mixed-type inhibitors extracted from Eriobotrya japonica Thunb. leaf exhibited excellent inhibition performance, and the inhibition efficiency for carbon steel reached 90.0% at 298 K in hydrochloric acid. Moreover, the adsorption mechanism of the inhibitors on a carbon steel surface is described by the Langmuir adsorption isotherm. Simultaneously, the corrosion morphology of the carbon steel and the inhibitor structure were analyzed by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively.

  13. Pomegranate (Punica granatum Peel Extract as a Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

    Directory of Open Access Journals (Sweden)

    Habib Ashassi-Sorkhabi

    2015-01-01

    Full Text Available The inhibition effect of pomegranate peel extract (PPE on the corrosion of mild steel in hydrochloric acid (HCl solution was investigated. The polarization, mass loss, and electrochemical impendence techniques were used to evaluate the corrosion inhibition performance of the pomegranate peel extract. The results revealed that PPE acts as a corrosion inhibitor in HCl solution. The inhibition efficiency increased with the increase of extract concentration. The inhibition action was attributed to the adsorption of the chemical compounds present in the extract solution, on mild steel surface.

  14. Leaching of vanadium from sulphuric acid manufacture spent catalysts

    Directory of Open Access Journals (Sweden)

    García, Diego Juan

    2001-02-01

    Full Text Available Recovery of vanadium contained in spent catalysts from the manufacture of sulphuric acid has been studied in this work, resulting in an industrial multistage process for the treatment of them avoiding direct deposition or dumping. Characterization of supplied spent catalysts samples, confirmed vanadium levels showed in the literature. The study of variables influencing leaching process: type of leaching agent, leaching agent concentration, S/L ratio, stirring speed and temperature, allows to fix the most advantageous conditions using industrial application criterion and verifying that the process is difusión controlled. The work is completed by developing an industrial leaching cycle simulation with the aim of reproducing real performance of spent catalyst, proposing operating conditions, and verifying the non-toxic character of the final residue obtained.

    En el presente trabajo se ha estudiado la recuperación del vanadio contenido en los catalizadores agotados procedentes de la fabricación del ácido sulfúrico, planteando un proceso industrial multietapa para el tratamiento de estos residuos, evitando su deposición o vertido directos. La caracterización de las muestras de catalizadores agotados disponibles confirmó los valores encontrados en la bibliografía. Se estudiaron las variables que influyen en el proceso de lixiviación (tipo de agente de lixiviación y concentración del mismo, relación S/L, velocidad de agitación y temperatura definiendo las condiciones más adecuadas desde el punto de vista industrial y verificando que el proceso está controlado por mecanismos difusionales. El trabajo se completa con la simulación de un ciclo industrial de lavado del catalizador y la verificación de la nula toxicidad de los lixiviados obtenidos por degradación del residuo final. 24 Aplicación de la resistencia de ruido al estudio de pinturas ricas en zinc Noise resistance applied to the study of zinc rich paints

  15. Adsorption of (4-amino-2-methyl-5-pyrimidinyl methylthio) acetic acid on mild steel from hydrochloric acid solution (HCl) - Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Abiola, O.K.; Oforka, N.C

    2004-02-15

    The adsorption of (4-amino-2-methyl-5-pyrimidinyl methylthio) acetic acid (AMMPTA) on mild steel from hydrochloric acid solution was studied using the weight loss and hydrogen evolution techniques. The corrosion rates of mild steel in hydrochloric acid solution containing AMMPTA are measured as a function of AMMPTA concentration. The degree of surface covered is used to calculate the free energy of adsorption, {delta}G{sub ad} of AMMPTA. The variation of negative free energy of adsorption, {delta}G{sub ad} with surface coverage, {theta} is interpreted in terms of change in mechanism of inhibitor action of AMMPTA with concentration. Phenomenon of physical adsorption is proposed. The effect of AMMPTA is discussed from the viewpoint of adsorption model. The thermodynamic parameters of adsorption process were obtained from experimental data using Bockris-Swinkels adsorption isotherm.

  16. Corrosion and Inhibition Effects of Mild Steel in Hydrochloric Acid Solutions Containing Organophosphonic Acid

    Directory of Open Access Journals (Sweden)

    Manish Gupta

    2013-01-01

    Full Text Available A study has been made on the mechanism of corrosion of mild steel and the effect of nitrilo trimethylene phosphonic (NTMP acid as a corrosion inhibitor in acidic medium, that is, 10% HC1 using the weight loss method and electrochemical techniques, that is, potentiodynamic and galvanostatic polarization measurements. Although corrosion is a long-time process, but it takes place at a faster rate in the beginning which goes on decreasing with due course of time. The above-mentioned methods of corrosion rate determination furnish an average value for a long-time interval. Looking at the versatility and minimum detection limit of the voltammetric method, the authors have developed a new voltammetric method for the determination of corrosion rate at short-time intervals. The results of corrosion of mild steel in 10% HC1 solution with and without NTMP inhibitor at short-time intervals have been reported. The corrosion inhibition efficiency of NTMP is 93% after 24 h.

  17. Separation of metal ions by anion exchange in mixtures of hydrochloric acid and hydrofluoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Faris, J.P.

    1978-12-01

    Distribution coefficients were determined for the adsorption of more than 40 elements on anion-exchange resins from mixtures of HCl (0.1 to 12M) and HF (0.1-8M). Two resins, Dowex 1 x 10, 200 to 400 mesh and Dowex 1 x 4, 100 to 200 mesh, were used. Distribution coefficients were also determined for the adsorption of many elements on both resins from 0.1 to 12M HCl and 0.1 to 12M HF. Anion exchange in the presence of HF was found useful for separating impurities from various materials for their subsequent determination, and specific procedures used in our spectrochemical laboratory for this purpose are outlined. The results of a literature search on the use of anion exchange in hydrofluoric acid and fluoride-containing media are presented in an extensive bibliography. 404 references, 9 tables.

  18. Fast pyrolysis of organic acid leached wood, straw, hay and bagasse: Improved oil and sugar yields

    NARCIS (Netherlands)

    Oudenhoven, Stijn; Westerhof, Roel Johannes Maria; Kersten, Sascha R.A.

    2015-01-01

    Organic acid leaching of pine wood, straw, bagasse and hay effectively reduced the amount of catalytically active alkali and alkaline earth metals (AAEMs). Using the (acetic) acid produced by pyrolysis as leaching agent, the AAEMs content could be reduced to 90–600 mg/kg. Tests with AAEMs

  19. Acidic leaching and precipitation of zinc and manganese from spent battery powders using various reductants.

    Science.gov (United States)

    Sayilgan, E; Kukrer, T; Yigit, N O; Civelekoglu, G; Kitis, M

    2010-01-15

    The main objective of this study was to investigate the effects of reductive acidic leaching and further precipitation on the recovery of manganese and zinc from spent alkaline and zinc-carbon battery powders. Ascorbic acid (AA), citric acid (CA) and oxalic acid (OA) were tested as the reductants. Sodium hydroxide and potassium hydroxide were used as precipitating agents. OA with H(2)SO(4) or HCl was not effective on the leaching of zinc due to the formation of zinc oxalate precipitates. However, the other reducing agents (CA and AA) tested under various experimental conditions were effective in the acidic leaching of both zinc and manganese. Leaching yields of both manganese and zinc were higher at leach temperature of 90 degrees C than those at 30 degrees C. Leach solutions were purified by the selective precipitation of manganese and zinc using KOH or NaOH. Complete precipitation was obtained for Mn at pH 9-10 and for Zn at pH 7-8. The use of ascorbic acid or citric acid as reductants in acidic leaching appears to be effective in the simultaneous leaching and further recovery of zinc and manganese from spent alkaline and zinc-carbon battery powders.

  20. Hydrochloric acid alters the effect of L-glutamic acid on cell viability in human neuroblastoma cell cultures.

    Science.gov (United States)

    Croce, Nicoletta; Bernardini, Sergio; Di Cecca, Stefano; Caltagirone, Carlo; Angelucci, Francesco

    2013-07-15

    l-Glutamic acid (l-glutamate) is used to induce excitotoxicity and test neuroprotective compounds in cell cultures. However, because l-glutamate powder is nearly insoluble in water, many manufacturers recommend reconstituting l-glutamate in hydrochloric acid (HCl) prior to successive dilutions. Nevertheless, HCl, even at low concentrations, may alter the pH of the cell culture medium and interfere with cell activity. Thus, the aim of this study was to evaluate whether the reconstitution of l-glutamate powder in HCl alters its capacity to induce neurotoxicity in different human neuroblastoma cell lines. SH-SY5Y, IMR-32 and SK-N-BE(2) cells were exposed to various concentrations of l-glutamate, which was either reconstituted in HCl (1M) or post re-equilibrated to the pH of the culture medium (7.5). After 24 and 48h of incubation, changes in the cell viability of treated versus untreated cells were evaluated. The effect of an identical amount of HCl present in the l-glutamate dilutions on neuroblastoma cell survival was also investigated. Our data showed that the neurotoxicity of glutamate reconstituted in HCl was comparable to that of HCl alone. Moreover, the pH variations induced by glutamate or HCl in the culture medium were similar. When the pH of the glutamate stock solution was re-equilibrated, l-glutamate induced variation in cell viability to a lower extent and after a longer incubation time. This study demonstrated that HCl used to reconstitute l-glutamate powder might alter the effect of glutamate itself in neuroblastoma cell cultures. Thus, this information might be useful to scientists who use l-glutamate to induce excitotoxicity or to test neuroprotective agents. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Corrosion inhibition of C38 steel in 1 M hydrochloric acid medium by alkaloids extract from Oxandra asbeckii plant

    Energy Technology Data Exchange (ETDEWEB)

    Lebrini, M. [Laboratoire Materiaux et Molecules en Milieu Amazonien, CNRS 8172-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana (France); Robert, F.; Lecante, A. [Laboratoire Materiaux et Molecules en Milieu Amazonien, UAG-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana (France); Roos, C., E-mail: christophe.roos@guyane.univ-ag.f [Laboratoire Materiaux et Molecules en Milieu Amazonien, UAG-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana (France)

    2011-02-15

    Research highlights: The inhibition effect of alkaloid extract of Oxandra asbeckii plant on the corrosion of C38 steel in 1 M hydrochloric acid solution has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Oxandra asbeckii extract examined acted as an efficient corrosion inhibitor in 1 M HCl. Polarization studies showed that Oxandra asbeckii extract was a mixed-type inhibitor and its inhibition efficiency increased with the inhibitor concentration. - Abstract: The inhibition effect of alkaloids extract from Oxandra asbeckii plant (OAPE) on the corrosion of C38 steel in 1 M hydrochloric acid solution has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The corrosion inhibition efficiency increases on increasing plant extracts concentration. Cathodic and anodic polarization curves show that OAPE is a mixed-type inhibitor. The effect of temperature on the corrosion behavior of C38 steel in 1 M HCl with and without addition of plant extract was studied in the temperature range 25-55 {sup o}C. The thermodynamic functions of dissolution and adsorption processes were calculated from experimental polarization data and the interpretation of the results are given. The adsorption of this plant extract on the C38 steel surface obeys the Langmuir adsorption isotherm. Surface analysis (Raman) was also carried out to establish the corrosion inhibitive property of this plant extract in HCl solution.

  2. Effect of the structural features of hydrochloric acid-deamidated wheat gluten on its susceptibility to enzymatic hydrolysis.

    Science.gov (United States)

    Cui, Chun; Hu, Qingling; Ren, Jiaoyan; Zhao, Haifeng; You, Lijun; Zhao, Mouming

    2013-06-19

    The effect of the structural features of hydrochloric acid-deamidated wheat gluten with different degrees of deamidation (DDs) on the susceptibility to enzymatic hydrolysis by pancreatin was investigated. The wheat gluten deamidated by hydrochloric acid with a DD of 55% revealed the highest susceptibility to enzymatic hydrolysis as evaluated by the hydrolysis degree and nitrogen solubility index of the hydrolysates. An increase of peptides with MW below 3000 Da was observed as the DD increased. Raman spectra in the 1740-1800 cm⁻¹ and 521-530 cm⁻¹ range suggested that wheat gluten had taken off the deamidation with different DDs and that the disulfide bond had disrupted the sulfhydryl groups with different intensities, respectively. Results from the deconvolution of the amide I region of FTIR spectra in the 1600-1700 cm⁻¹ range showed that the content of the α-helix decreased and that the content of the β-turn and β-sheet increased with increasing DDs, which improved the molecular structure and flexibility of wheat gluten. A scanning electron microscope (SEM) revealed that the image of HDG-55% presented the smoothest surface and the least uniform pore, enabling the sample to be more susceptible to enzymatic hydrolysis. The above information will enable us to better understand the effect of structure on the susceptibility of deamidated wheat gluten.

  3. Effect of Hydrochloric Acid Decalcification on Expression Pattern of Prognostic Markers in Invasive Breast Carcinomas.

    Science.gov (United States)

    Maclary, Shawn C; Mohanty, Sambit K; Bose, Shikha; Chung, Fai; Balzer, Bonnie L

    2017-02-01

    In the United States, it is estimated that 100,000 people are living with metastatic breast cancer (BC) with bone representing the most common site of involvement. However, patients with isolated bone metastasis at presentation may have a longer survival. Therapeutic options for BC bone metastases often include systemic anticancer therapy (endocrine, chemotherapy, monoclonal antibodies, and/or other targeted therapies), which is largely dependent on the immunohistochemical (IHC) repertoire of the cancer for the prognostic markers [estrogen (ER) and progesterone receptors (PR), Ki-67, p53, and Her-2/neu] at its osseous metastatic site. Traditionally, specimens obtained from the bone metastasis require decalcification, which may affect the immunoreactivity of these prognostic markers. To the best of our knowledge, limited studies describe the effect of decalcification on immunoexpression of the above-mentioned markers. A detailed illustration of the effect of decalcification on BC specimens in a real-time manner is lacking in the literature. Herein, we sought to determine the impact of decalcification on the IHC expression pattern of the above listed markers on BC tissue following decalcification. After Institutional Review Board approval, sections from the residual tumor specimens were collected prospectively from 15 BC excision specimens and 1 curetting from a BC bone metastasis. The sections (3 to 6 sections/case) for decalcification were collected following routine submission for pathologic evaluation. The sections were subjected to hydrochloric acid (HCl)-based Decal Stat decalcifying solution for 2, 12, 18, and 24 hours in each case. IHC studies for ER, PR, Ki-67, p53, and Her-2/neu were performed on 1 representative section of the regularly processed tumor block and 1 decalcified tumor block from each time point. Scoring of ER and PR were performed according to the Allred scoring system. Scoring of Her-2/neu was performed according to CAP/ASCO guidelines. The

  4. Kinetics of Rare Earth Extraction from Baotou Bastnaesite in Hydrochloric Acid and Aluminum Chloride

    Science.gov (United States)

    Zhang, Xiao-Wei; Li, Mei; Liu, Zhao-Gang; Hu, Yan-Hong; Wang, Mi-Tang

    2017-10-01

    In this paper, the leaching kinetics of rare earth from Baotou bastnaesite in a HCl-AlCl3 solution was investigated. In addition, the effects of the HCl and AlCl3 concentrations, liquid to solid ratio, stirring speed, temperature, and time spent on the rare earth extraction were determined. The results indicated that the extraction was nearly independent of the stirring speed when it did not exceed 300 rpm, and the rate of leaching increased with increases in the HCl and AlCl3 concentrations, liquid to solid ratio, temperature, and time. The optimum dissolution conditions were determined under five experimental conditions. After leaching occurred, the progressive dissolution of the bastnaesite phase could be determined. The leaching kinetics was analyzed with a new variant of the shrinking core model in which both the interfacial transfer and diffusion across the product layer affected the rare earth extraction. The apparent activation energy was 35.57 kJ/mol, and the Arrhenius constant was 341.58 min-1. An empirical equation was derived to describe the extraction process of rare earth minerals.

  5. A Study of N,N-Diethylammonium O,O′-Di(p-methoxyphenyldithiophosphate as New Corrosion Inhibitor for Carbon Steel in Hydrochloric Acid Solution

    Directory of Open Access Journals (Sweden)

    Chuan Lai

    2016-01-01

    Full Text Available N,N-Diethylammonium O,O′-di(p-methoxyphenyldithiophosphate (EAPP as a new corrosion inhibitor was synthesized in the present work. The corrosion inhibition of EAPP in hydrochloric acid for carbon steel was evaluated by potentiodynamic polarization measurements, electrochemical impedance spectroscopy, weight loss measurements, and scanning electron microscopy. The results indicate that the EAPP is mixed type inhibitor, and the adsorption of EAPP on carbon steel surface obeys Langmuir isotherm. In addition, the inhibition efficiency increases with increasing the concentration of inhibitor and decreases with increasing the hydrochloric acid concentration, temperature, and storage time.

  6. Spontaneous breathing with biphasic positive airway pressure attenuates lung injury in hydrochloric acid-induced acute respiratory distress syndrome.

    Science.gov (United States)

    Xia, Jingen; Zhang, Heng; Sun, Bing; Yang, Rui; He, Hangyong; Zhan, Qingyuan

    2014-06-01

    It has been proved that spontaneous breathing (SB) with biphasic positive airway pressure (BIPAP) can improve lung aeration in acute respiratory distress syndrome compared with controlled mechanical ventilation. The authors hypothesized that SB with BIPAP would attenuate lung injury in acute respiratory distress syndrome compared with pressure-controlled ventilation. Twenty male New Zealand white rabbits with hydrochloric acid aspiration-induced acute respiratory distress syndrome were randomly ventilated using the BIPAP either with SB (BIPAP plus SB group) or without SB (BIPAP minus SB group) for 5 h. Inspiration pressure was adjusted to maintain the tidal volume at 6 ml/kg. Both groups received the same positive end-expiratory pressure level at 5 cm H2O for hemodynamic goals. Eight healthy animals without ventilatory support served as the control group. The BIPAP plus SB group presented a lower ratio of dead space ventilation to tidal volume, a lower respiratory rate, and lower minute ventilation. No significant difference in the protein levels of interleukin-6 and interleukin-8 in plasma, bronchoalveolar lavage fluid, and lung tissue were measured between the two experimental groups. However, SB resulted in lower messenger ribonucleic acid levels of interleukin-6 (mean ± SD; 1.8 ± 0.7 vs. 2.6 ± 0.5; P = 0.008) and interleukin-8 (2.2 ± 0.5 vs. 2.9 ± 0.6; P = 0.014) in lung tissues. In addition, lung histopathology revealed less injury in the BIPAP plus SB group (lung injury score, 13.8 ± 4.6 vs. 21.8 ± 5.7; P hydrochloric acid-induced acute respiratory distress syndrome, SB with BIPAP attenuated lung injury and improved respiratory function compared with controlled ventilation with low tidal volume.

  7. Extraction of vanadium from vanadium slag by high pressure oxidative acid leaching

    Science.gov (United States)

    Zhang, Guo-quan; Zhang, Ting-an; Lü, Guo-zhi; Zhang, Ying; Liu, Yan; Liu, Zhuo-lin

    2015-01-01

    To extract vanadium in an environment friendly manner, this study focuses on the process of leaching vanadium from vanadium slag by high pressure oxidative acid leaching. Characterizations of the raw slag, mineralogy transformation, and the form of leach residues were made by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The result shows that the vanadium slag is composed of major phases of fayalite, titanomagnetite, and spinel. During the high pressure oxidative acid leaching process, the fayalite and spinel phases are gradually decomposed by sulfuric acid, causing the release of vanadium and iron in the solution. Meanwhile, unreacted silicon and titanium are enriched in the leach residues. With the initial concentration of sulfuric acid at 250 g·L-1, a leaching temperature of 140°C, a leaching time of 50 min, a liquid-solid ratio of 10:1 mL·g-1, and oxygen pressure at 0.2 MPa, the leaching rate of vanadium reaches 97.69%.

  8. Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide.

    Science.gov (United States)

    Jadhav, Umesh; Su, C; Hocheng, Hong

    2016-12-01

    In the present study, the leaching of metals from large pieces of computer printed circuit boards (CPCBs) was studied. A combination of citric acid (0.5 M) and 1.76 M hydrogen peroxide (H2O2) was used to leach the metals from CPCB piece. The influence of system variables such as H2O2 concentration, concentration of citric acid, shaking speed, and temperature on the metal leaching process was investigated. The complete metal leaching was achieved in 4 h from a 4 × 4 cm CPCB piece. The presence of citric acid and H2O2 together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H2O2 was 5.83 %. The citric acid concentration and shaking speed had an insignificant effect on the leaching of metals. The increase in the temperature above 30 °C showed a drastic effect on metal leaching process.

  9. Acidic leaching of copper and tin from used consumer equipment

    Directory of Open Access Journals (Sweden)

    Orac D.

    2015-01-01

    Full Text Available This work is focused on studying thermal pretreatment and leaching of copper and tin from printed circuit boards (PCBs from used consumer equipment. Thermal treatment experiments were realized with and without presence of oxygen at 300°C, 500°C, 700°C and 900°C for 30 minutes. Leaching experiments were performed at 80°C in 2M HCl in two stages. The first stage consisted of classic leaching experiments of samples without and after thermal treatment. The second stage consisted of oxidative leaching experiments (blowing of air or oxygen with the aim to intensify metals leaching. The results of thermal treatment experiments show that maximal mass loss after burning (combustion was 53 % (700°C and after pyrolysis 47 % (900 %. Oxidative leaching resulted in complete dissolution of copper and tin after 60. or 90 minutes of thermally treated samples. Pyrolysis and combustion have positive effects on metals dissolution in comparison with samples without thermal pretreatment. Moreover, the dissolution of metals is more effective and needs shorter leaching time.

  10. Adsorption and corrosion inhibition of mild steel in hydrochloric acid solution by S-allyl-O,O‧-dialkyldithiophosphates

    Science.gov (United States)

    Lai, Chuan; Xie, Bin; Zou, Like; Zheng, Xingwen; Ma, Xiao; Zhu, Shasha

    Here, S-allyl-O,O‧-diphenyldithiophosphate(SOD1), S-allyl-O,O‧-dibenzyldithiophosphate (SOD2) and S-allyl-O,O‧-di(2-phenylethyl)dithiophosphate(SOD3) were successful synthesized and characterized, which acting as the novel corrosion inhibitors for mild steel in hydrochloric acid (HCl) solution were evaluated by electrochemical measurements, weight loss measurement and scanning electron microscopy. Potentiodynamic polarization measurement indicates that the synthesized inhibitors are effective mixed-type inhibitors. The inhibition efficiency increases with inhibitor concentration increasing, decreases with HCl concentration and temperature increasing. The adsorption of SOD1, SOD2 and SOD3 on mild steel surface obeys Langmuir isotherm. The adsorption of SOD1 and SOD3 on mild steel surface is a mixed adsorption involving both physisorption and chemisorption, and that the adsorption of SOD2 on mild steel surface belongs to chemical adsorption.

  11. Electrochemical study on inhibitory effect of Aspirin on mild steel in 1 M hydrochloric acid

    Directory of Open Access Journals (Sweden)

    B.M. Prasanna

    2017-02-01

    Full Text Available Aspirin was investigated as a good corrosion inhibitor for mild steel in 1 M hydrochloric acid at a temperature region from 303 to 333 K. The computed inhibition efficiency increases by increasing the inhibitor concentration and decreases by increasing the temperature. The investigation was done by weight loss, electrochemical measurements such as Tafel polarization and electrochemical impedance spectroscopy. Inhibition effect is attributed to the adsorption of inhibitor on the surface of the mild steel. The Tafel method reveals that the Aspirin acts as a mixed type inhibitor. Activation parameters suggest that the adsorption process is exothermic in nature. SEM photographs of mild steel in the absence and presence of inhibitor visualize the adsorption layer on the surface of the mild steel.

  12. Theoretical, thermodynamic and electrochemical analysis of biotin drug as an impending corrosion inhibitor for mild steel in 15% hydrochloric acid

    Science.gov (United States)

    Xu, Xihua; Sun, Zhipeng; Ansari, K. R.; Lin, Yuanhua

    2017-01-01

    The corrosion mitigation efficiency of biotin drug for mild steel in 15% hydrochloric acid was thoroughly investigated by weight loss and electrochemical methods. The surface morphology was studied by the contact angle, scanning electrochemical microscopy, atomic force microscopy and scanning electron microscopy methods. Quantum chemical calculation and Fukui analysis were done to correlate the experimental and theoretical data. The influence of the concentration of inhibitor, immersion time, temperature, activation energy, enthalpy and entropy has been reported. The mitigation efficiency of biotin obtained by all methods was in good correlation with each other. Polarization studies revealed that biotin acted as a mixed inhibitor. The adsorption of biotin was found to obey the Langmuir adsorption isotherm. Surface studies showed the hydrophobic nature of the steel with inhibitor and vindicated the formation of a film on the metal surface that reduced the corrosion rate. PMID:29308235

  13. Growth and membrane fluidity of food-borne pathogen Listeria monocytogenes in the presence of weak acid preservatives and hydrochloric acid.

    Science.gov (United States)

    Diakogiannis, Ioannis; Berberi, Anita; Siapi, Eleni; Arkoudi-Vafea, Angeliki; Giannopoulou, Lydia; Mastronicolis, Sofia K

    2013-01-01

    This study addresses a major issue in microbial food safety, the elucidation of correlations between acid stress and changes in membrane fluidity of the pathogen Listeria monocytogenes. In order to assess the possible role that membrane fluidity changes play in L. monocytogenes tolerance to antimicrobial acids (acetic, lactic, hydrochloric acid at low pH or benzoic acid at neutral pH), the growth of the bacterium and the gel-to-liquid crystalline transition temperature point (T m) of cellular lipids of each adapted culture was measured and compared with unexposed cells. The T m of extracted lipids was measured by differential scanning calorimetry. A trend of increasing T m values but not of equal extent was observed upon acid tolerance for all samples and this increase is not directly proportional to each acid antibacterial action. The smallest increase in T m value was observed in the presence of lactic acid, which presented the highest antibacterial action. In the presence of acids with high antibacterial action such as acetic, hydrochloric acid or low antibacterial action such as benzoic acid, increased T m values were measured. The T m changes of lipids were also correlated with our previous data about fatty acid changes to acid adaptation. The results imply that the fatty acid changes are not the sole adaptation mechanism for decreased membrane fluidity (increased T m). Therefore, this study indicates the importance of conducting an in-depth structural study on how acids commonly used in food systems affect the composition of individual cellular membrane lipid molecules.

  14. Particulates in hydrometallurgy: Part II. Dewatering behavior of unflocculated laterite acid leach residues

    Science.gov (United States)

    Briceno, A.; Osseo-Asare, K.

    1995-02-01

    The effects of ore type and leaching conditions ( e.g., temperature and solid/liquid ratio) on the settling behavior of laterite acid leach residues were investigated. Settling rate, supernatant turbidity, and filtrability of the slurry were used in evaluating the settling behavior. The slurries showed three different regimes of sedimentation, involving free, hindered, and compression settling behavior. An improvement in the dewatering characteristics of the leach residues was observed as the leaching temperature was increased. Furthermore, the leach residues showed markedly different settling behaviors depending on the temperature. Below 175°C, the settling rate for both 2.5 and 25 pct solids increased steadily with temperature. However, the results indicated clearly that at higher temperatures (>175°C), there is a steep increase in settling rate. These pronounced differences in settling behavior with temperature increase are believed to be due to the sharp increase in particle size above 175°C. The mineral content in the ore has a great effect on the settling behavior of the leach residues. It was found that the oxide-silicate material (Ore No. 2 leach residues) showed a lower settling rate than the iron-rich material (Ore No. 1 leach residues). This behavior is attributable to the presence of a gelatinous, siliceous product in the Ore No. 2 leached pulp.

  15. Green approach to corrosion inhibition of mild steel in hydrochloric acid and sulphuric acid solutions by the extract of Murraya koenigii leaves

    Energy Technology Data Exchange (ETDEWEB)

    Quraishi, M.A., E-mail: maquraishi@rediffmail.com [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India); Singh, Ambrish; Singh, Vinod Kumar [Udai Pratap Autonomous College, Varanasi 221002 (India); Yadav, Dileep Kumar; Singh, Ashish Kumar [Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India)

    2010-07-01

    The inhibition of the corrosion of mild steel in hydrochloric acid and sulphuric acid solutions by the extract of Murraya koenigii leaves has been studied using weight loss, electrochemical impedance spectroscopy (EIS), linear polarization and potentiodynamic polarization techniques. Inhibition was found to increase with increasing concentration of the leaves extract. The effect of temperature, immersion time and acid concentration on the corrosion behavior of mild steel in 1 M HCl and 0.5 M H{sub 2}SO{sub 4} with addition of extract was also studied. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the metal surface. The adsorption of the extract on the mild steel surface obeys the Langmuir adsorption isotherm. The activation energy as well as other thermodynamic parameters (Q, {Delta}H*, and {Delta}S*) for the inhibition process was calculated. These thermodynamic parameters show strong interaction between inhibitor and mild steel surface. The results obtained show that the extract of the leaves of M. koenigii could serve as an effective inhibitor of the corrosion of mild steel in hydrochloric and sulphuric acid media.

  16. A kinetic study of plutonium dioxide dissolution in hydrochloric acid using iron (II) as an electron transfer catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Fife, K.W.

    1996-09-01

    Effective dissolution of plutonium dioxide has traditionally been accomplished by contact with strong nitric acid containing a small amount of fluoride at temperatures of {approximately} 100 C. In spite of these aggressive conditions, PuO{sub 2} dissolution is sometimes incomplete requiring additional contact with the solvent. This work focused on an alternative to conventional dissolution in nitric acid where an electron transfer catalyst, Fe(II), was used in hydrochloric acid. Cyclic voltammetry was employed as an in-situ analytical technique for monitoring the dissolution reaction rate. The plutonium oxide selected for this study was decomposed plutonium oxalate with > 95% of the material having a particle diameter (< 70 {micro}m) as determined by a scanning laser microscopy technique. Attempts to dry sieve the oxide into narrow size fractions prior to dissolution in the HCl-Fe(II) solvent system failed, apparently due to significant interparticle attractive forces. Although sieve splits were obtained, subsequent scanning laser microscopy analysis of the sieve fractions indicated that particle segregation was not accomplished and the individual sieve fractions retained a particle size distribution very similar to the original powder assemblage. This phenomena was confirmed through subsequent dissolution experiments on the various screen fractions which illustrated no difference in kinetic behavior between the original oxide assemblage and the sieve fractions.

  17. Experimental design and process analysis for acidic leaching of metal-rich glass wastes.

    Science.gov (United States)

    Tuncuk, A; Ciftci, H; Akcil, A; Ognyanova, A; Vegliò, F

    2010-05-01

    The removal of iron, titanium and aluminium from colourless and green waste glasses has been studied under various experimental conditions in order to optimize the process parameters and to decrease the metal content in the waste glass by acidic leaching. Statistical design of experiments and ANOVA (analysis of variance) were performed in order to determine the main effects and interactions between the investigated factors (sample ratio, acid concentration, temperature and leaching time). A full factorial experiment was performed by sulphuric acid leaching of glass for metal removal. After treating, the iron content was 530 ppm, corresponding to 1880 ppm initial concentration of Fe(2)O(3) in the original colourless sample. This result is achieved using 1M H(2)SO( 4) and 30% sample ratio at 90(o)C leaching temperature for 2 hours. The iron content in the green waste glass sample was reduced from 3350 ppm initial concentration to 2470 ppm after treating.

  18. [Butanol extraction combined with dilute hydrochloric acid dissolution-atomic fluorescence spectrometric method for indirect determination of molybdenum in Chinese herbal medicine].

    Science.gov (United States)

    Lu, Jian-Ping; Geng, Guo-Xing; Tang, Yan-Kui; Lu, Zhi-Yong

    2012-12-01

    A method for indirectly determining the molybdenum in Chinese herbal medicine by butanol extraction and dilute hydrochloric acid dissolution was established for atomic fluorescence spectrometry. The molybdoarsenate heteropoly acid, formed in the presence of As(V) and ammonium molybdate in 0.3 mol x L(-1) sulphuric acid medium, was separated and enriched in the organic solvent, then the evaporation of organic reagent was implemented and the left residue was dissolved in dilute hydrochloric acid in which the arsenic content was determined on behalf of molybdenum. In the optimum experimental conditions, molybdenum content in 0-15 microg x L(-1) range depicts a good linear relationship, the detection limit and relative standard deviation of 0.44 microg x L(-1) and 1.1% were obtained, respectively. Spiked Chinese herbal medicine samples were determined with the proposed method, and recoveries of 95.6%-101.3% were achieved.

  19. Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.

    Science.gov (United States)

    Xu, Honggao; Tai, Kedong; Wei, Tong; Yuan, Fang; Gao, Yanxiang

    2017-11-01

    Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study. The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g-1 . The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P hydrochloric acid solution (HP), while the mean molecular weight of SP was lower than that of HP. Compared with HP, SP exhibited higher viscosity and better emulsifying property. Based on the yield and physicochemical properties of hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Loss of muscarinic and purinergic receptors in urinary bladder of rats with hydrochloric acid-induced cystitis.

    Science.gov (United States)

    Yoshida, Akira; Kageyama, Aiko; Fujino, Tomomi; Nozawa, Yoshihisa; Yamada, Shizuo

    2010-10-01

    To clarify the basic mechanism involved in the pathophysiology of cystitis by characterizing the urodynamic parameters, pharmacologically relevant (muscarinic and purinergic) receptors, and the in vivo release of adenosine triphosphate (ATP) in the bladder of hydrochloric acid (HCl)-treated rats. The muscarinic and purinergic receptors in rat tissue were measured by radioreceptor assays using (N-methyl-³H) scopolamine methyl chloride ([³H]NMS) and αβ-methylene-ATP (2,8-³H) tetrasodium salt ([³H]αβ-MeATP), respectively. The urodynamic parameters and ATP levels were measured using a cystometric method and the luciferin-luciferase assay, respectively. In the HCl-treated rats, the micturition interval and micturition volume were significantly (48% and 55%, respectively, P acid tetrasodium, and MRS2273 was significantly (5.5, 11, and 7.6-fold, respectively, P <.001) increased. Furthermore, the in vivo release of ATP was significantly (P <.05) enhanced in the HCl-treated rat bladder. Both muscarinic and purinergic mechanisms might be, at least in part, associated with the urinary dysfunction due to cystitis. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Interaction between amylose and 1-butanol during 1-butanol-hydrochloric acid hydrolysis of normal rice starch.

    Science.gov (United States)

    Hu, Xiuting; Wei, Benxi; Zhang, Bao; Li, Hongyan; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2013-10-01

    The aim of this study was to examine the interaction between amylose and 1-butanol during the 1-butanol-hydrochloric acid (1-butanol-HCl) hydrolysis of normal rice starch. The interaction model between amylose and 1-butanol was proposed using gas chromatography-mass spectrometry (GC-MS), (13)C cross polarization and magic angle spinning NMR analysis ((13)C CP/MAS NMR), differential scanning calorimetry (DSC), and thermalgravimetric analysis (TGA). GC-MS data showed that another form of 1-butanol existed in 1-butanol-HCl-hydrolyzed normal rice starch, except in the form of free molecules absorbed on the starch granules. The signal of 1-butanol-HCl-hydrolyzed starch at 100.1 ppm appeared in the (13)C CP/MAS NMR spectrum, indicating that the amylose-1-butanol complex was formed. DSC and TGA data also demonstrated the formation of the complex, which significantly affected the thermal properties of normal rice starch. These findings revealed that less dextrin with low molecular weight formed might be attributed to resistance of this complex to acid during 1-butanol-HCl hydrolysis. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  2. Retrospective Review of Hydrochloric Acid Infusion for the Treatment of Metabolic Alkalosis in Surgical Intensive Care Unit Patients.

    Science.gov (United States)

    Guffey, Jason D; Haas, Curtis E; Crowley, Amber; Connor, Kathryn A; Kaufman, David C

    2018-01-01

    Older reports of use of hydrochloric acid (HCl) infusions for treatment of metabolic alkalosis document variable dosing strategies and risk. This study sought to characterize use of HCl infusions in surgical intensive care unit patients for the treatment of metabolic alkalosis. This retrospective review included patients who received a HCl infusion for >8 hours. The primary end point was to evaluate the utility of common acid-base equations for predicting HCl dose requirements. Secondary end points evaluated adverse effects, efficacy, duration of therapy, and total HCl dose needed to correct metabolic alkalosis. Data on demographics, potential causes of metabolic alkalosis, fluid volume, and duration of diuretics as well as laboratory data were collected. A total of 30 patients were included, and the average HCl infusion rate was 10.5 ± 3.7 mEq/h for an average of 29 ± 14.6 hours. Metabolic alkalosis was primarily diuretic-induced (n = 26). Efficacy was characterized by reduction in the median total serum CO2 from 34 to 27 mM/L ( P < 0.001). The change in chloride ion deficit and change in apparent strong ion difference (SIDa) were not correlated with total HCl administered. There were no documented serious adverse effects related to HCl infusions. HCl was effective for treating metabolic alkalosis, and no serious adverse events were seen. In this clinical setting, the baseline chloride ion deficit and SIDa were not useful for prediction of total HCl dose requirement, and serial monitoring of response is recommended.

  3. Ultrasound effects on zinc recovery from EAF dust by sulfuric acid leaching

    Science.gov (United States)

    Brunelli, K.; Dabalà, M.

    2015-04-01

    In this work, an ultrasound-assisted leaching process was studied for the recovery of zinc from electric arc furnace (EAF) dust, in which zinc was mainly present in the form of franklinite (60%). Hydrometallurgy is emerging as a preferred process for the recovery of a variety of metals, and the use of ultrasound could offer advantages over the conventional leaching process, especially for the dissolution of franklinite. Franklinite is a refractory phase that is difficult to leach and represents the main obstacle in conventional hydrometallurgy processing. Atmospheric leaching with different sulfuric acid concentrations (0.2-2.0 M) at two temperatures (323 and 353 K) was performed. The tests were conducted using both conventional and ultrasound-assisted leaching. After the leaching tests, the solid residues were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques, whereas the leach liquor was analyzed by inductively coupled plasma spectroscopy (ICP). The use of ultrasound facilitated the dissolution of franklinite at low acid concentrations and resulted in a greater zinc recovery under all of the investigated operating conditions.

  4. Influences of organic cation and hydrochloric acid additive on the morphology and photoluminescence of HC(NH2)2PbBr3 films

    Science.gov (United States)

    Yan, Jun; Chen, Yunlin; Wang, Ji; Zhang, Ao; Zhang, Bing

    2017-11-01

    The hydrohalic acid additives have been used in perovskite thin films to improve the film morphology and optical properties. However, our study demonstrated that the hydrochloric acid (HCl) additive greatly improved the surface coverage but lowered the photoluminescence (PL) emission intensities of HC(NH2)2PbBr3 (HC(NH2)2 = FA) films. The effects of organic cation and hydrochloric acid additive on the morphology and photoluminescence of FAPbBr3 films were investigated. We found that FAPbBr3 films prepared with HCl additive in low FABr concentration environment displayed good film quality but weak PL emission intensity. The optical properties of FAPbBr3 films have close relationship with FABr concentration. The optical absorption edge of FAPbBr3 showed a blue shift with increasing the FABr concentration. The strong PL emission intensities of FAPbBr3 can be obtained from the solutions with high FABr concentration.

  5. Extraction of uranium from tailings by sulfuric acid leaching with oxidants

    Science.gov (United States)

    Huang, Jing; Li, Mi; Zhang, Xiaowen; Huang, Chunmei; Wu, Xiaoyan

    2017-06-01

    Recovery of uranium have been performed by leaching uranium-containing tailings in sulfuric acid system with the assistance of HF, HClO4, H2O2 and MnO2. The effect of reagent dosage, sulfuric acid concentration, Liquid/solid ratio, reaction temperature and particle size on the leaching of uranium were investigated. The results show that addiction of HF, HClO4, H2O2 and MnO2 significantly increased the extraction of uranium under 1M sulphuric acid condition and under the optimum reaction conditions a dissolution fraction of 85% by HClO4, 90% by HF, 95% by H2O2 can be reached respectively. The variation of technological mineralogy properites of tailings during leaching process show that the assistants can break gangue effectively. These observations suggest that optimum oxidants could potentially influence the extraction of uranium from tailings even under dilute acid condition.

  6. Effects of hyperbaric oxygen therapy on hydrochloric acid-induced interstitial cystitis in rats: a histological and ultrastructural study.

    Science.gov (United States)

    Yilmaz, Mehmet; Cakmak, Tolga; Yenilmez, Aydin; Baseskioglu, Barbaros; Metin, Suleyman

    2016-01-01

    Currently no definitive cure exists for interstitial cystitis (IC). We investigated the therapeutic effects of hyperbaric oxygen (HBO₂) therapy in this syndrome in an experimental IC model through biochemical analyses and histopathological assessments. 24 Sprague Dawley rats were divided into three treatment groups sham (transurethral intravesical injection with sterile distilled water), rats with IC (induced by transurethral intravesical injection with hydrochloric acid), and rats with IC + HBO₂. After completion of experiments the animals were sacrificed and their urinary bladders were removed surgically. Tissues were evaluated by light and electron microscopy. Lesion index scoring system for IC was used to evaluate vesical injury. TNF-α levels were measured by ELISA test kit. Lesion index scores and TNF-α levels of the sham and IC + HBO₂ treatment groups were quite similar (p 0.05), it reduced the mast cell activity (p 0.05) were improved in the IC + HBO₂ treatment group compared to the IC without HBO₂ treatment group. HBO₂ treatment may alleviate the inflammation, may lead to a certain degree of reversal of adverse histopathological changes, and is effective in enhancing the healing process in interstitial cystitis. We believe that HBO₂ treatment may be included as a weapon in our armamentarium against IC.

  7. Effect of Nickel Content on the Corrosion Resistance of Iron-Nickel Alloys in Concentrated Hydrochloric Acid Pickling Solutions

    Directory of Open Access Journals (Sweden)

    Nabeel Alharthi

    2017-01-01

    Full Text Available The effect of Ni content on the resistance against corrosion of Fe-36% Ni and Fe-45% Ni alloys in 1 M hydrochloric acid pickling solution was reported. Various electrochemical and spectroscopic techniques such as potentiodynamic cyclic polarization (CPP, open-circuit potential (OCP, electrochemical impedance spectroscopy (EIS, potentiostatic current-time (PCT, and scanning electron microscopy (SEM, and energy dispersive spectroscopy (EDS have been employed. CPP measurements indicated that the corrosion current and corrosion rate recorded lower values for the alloy that had higher nickel content. OCP curves proved that the presence of high Ni content shifts the absolute potential to the positive potential direction. EIS results revealed that the surface and polarization resistances were much higher for the alloy with higher Ni content. PCT curves also showed that the absolute currents were lower for Fe-45% Ni alloy. All results were in good agreement with others and confirmed clearly that the corrosion resistance in HCl solutions for Fe-45% Ni alloy was higher than that obtained for Fe-45% Ni alloy.

  8. Leaching behaviour of a galvanic sludge in sulphuric acid and ammoniacal media.

    Science.gov (United States)

    Silva, J E; Soares, D; Paiva, A P; Labrincha, J A; Castro, F

    2005-05-20

    Leaching studies of a sludge produced by the physico-chemical treatment of wastewaters generated by a Ni/Cr plating plant were carried out in both sulphuric acid and ammoniacal media aiming to decide which of them would be the best treatment for this kind of waste material. The dissolution behaviour of some metals (Cu, Ni, Cr and Zn) was studied in order to assure the best metal recovery conditions in subsequent processes by the use of some separation methods such as solvent extraction and precipitation techniques. Therefore, the study here presented deals with the first chemical stage of an integrated treatment process. For the sulphuric acid leaching, maximal conversions obtained were 88.6% Cu, 98.0% Ni and 99.2% Zn for the following experimental conditions: a 100 g L(-1) acid concentration, a 5:1 liquid-to-solid ratio (L/S), a particle size less than 1 mm, a digestion time of 1h, a stirring speed of 700 rpm (all at room temperature and under atmospheric pressure). As expected, no selectivity was achieved for the sulphuric acid leaching, despite this option yielding much higher metal ion dissolution when compared with that reached by ammoniacal leaching. The use of this latter medium allowed the extraction of Cu and Ni without Cr species, but rates of conversion were only about 70% for Cu and 50% for Ni, much lower than those obtained for sulphuric acid leaching.

  9. Kinetics, aggregation behavior and optimization of the fractionation of whey protein isolate with hydrochloric acid

    Science.gov (United States)

    Concentrated WPI solutions (10% (w/w)) containing approximately 30% alpha-lactalbumin (alpha-LA) and 60% beta-lactoglobulin (beta-LG) were fractionated with HCl at acidic pH and moderate temperatures to denature alpha-LA and recover the alpha-LA aggregates via centrifugation. Aggregation behavior an...

  10. A Kinetic study of leaching of coal pyrite with nitric acid

    Science.gov (United States)

    Cho, Eung Ha; Chang, Kevin H.; Rollins, Ronald R.

    1983-09-01

    The leaching of coal pyrite with nitric acid has been investigated. The temperature ranged from 313 to 363 K, and the concentration of nitric acid was varied from 0.154 to 1.54 mol/l. A coal sample of 50 grams was leached in a reactor containing 500 ml of solution in an open system. It was observed that the leaching reaction could remove 47 pct of the pyrite sulfur in seven minutes and 88 pct in 30 minutes at 343 K with 1.54 mol/l of nitric acid. The reaction order with respect to hydrogen and nitrate ion activity was found to be first order. The activation energy for the initial stage of the reaction was determined to be 14.7 K cal/mol (61.5 kJ/mol). A mathematical model was developed on the basis of mixed kinetics (reaction zone model) to explain the leaching rates. Good agreement between experimental rate data and predicted rate curves by the developed model was obtained. Ultimate analysis was used to determine the extent of nitration of the leached coal. This nitration was found to be insensitive to the reaction temperature and acidity of the solution.

  11. Kinetic study of the manganese mine tailings leaching by organic reductant in sulfuric acid solution

    Directory of Open Access Journals (Sweden)

    Abdallah A.

    2015-01-01

    Full Text Available A kinetic study of the leaching of manganese mining residue by sulfuric acid and potassium oxalate has been investigated. The effects of the reaction agitation speed, manganese ore particle size, acid concentration, oxalate concentration and temperature on manganese rate dissolved. The leaching rates are significantly influenced by the Reaction temperature, to both concentration oxalate and acid. The observed effects of the relevant operating variables on the leaching rates are consistent with a kinetic model for chemical control. The apparent activation energy for the leaching of pyrolusite has been calculated using the Arrhenius expression and was found to be (63.7±2.9 kJ/mol. The experimental results indicate a reaction order of 1.07 for [H2SO4] concentration and 0.96 for [K2C2O4]. It is concluded that the reductive leaching of pyrolusite with potassium oxalate in acid medium is controlled by chemical reaction. The rate expression associated with the dissolution rate of pyrolusite depending on the parameters chosen may be summarized as follows: 1 - (1 - x1/3 = 1.45 10 7/r0.92 0 ∙ [H2SO4]1.07 [K2C2O4]0.96exp(-63735/RT∙t.

  12. Effect of Hydrochloric Acid (HCl) on Synthesis and Anisotropic Phenomena of Triglycine Phosphate (TGP) Single Crystals

    OpenAIRE

    Meera, M R; Rayar, SL; Bena Jothy, V,

    2017-01-01

    International audience; Effect of Sulphuric acid (H2SO4) addition on the growth of triglycine phosphate (TGP) crystal has been studied from the aqueous solution by slow evaporation technique. The characteristics absorption bands of pure and H2SO4 admixtured TGP crystals are confirmed by FTIR spectra. UV-visible transmittance spectra were recorded for the samples to analyze the transparency of the grown crystals. The composition of pure and doped TGP crystals have been confirmed by EDAX analys...

  13. In vitro effects of hydrochloric and lactic acids on bioelectric properties of equine gastric squamous mucosa.

    Science.gov (United States)

    Andrews, F M; Buchanan, B R; Elliott, S B; Al Jassim, R A M; McGowan, C M; Saxton, A M

    2008-06-01

    Volatile fatty acids, byproducts of carbohydrate fermentation by resident bacteria, have been implicated in causing nonglandular (NG) gastric ulcers. Lactic acid (LA), also produced by stomach bacteria, may cause gastric ulcers when exposed to the equine NG mucosa. To investigate the in vitro effects of LA on equine NG mucosa bioelectric properties, sodium transport and tissue resistance. Gastric tissues obtained from 13 mature horses were studied in Ussing chambers. Short-circuit current (Isc) and potential difference (PD) were measured, and electrical resistance (R) and conductance (G) calculated for tissues after addition of HCl and LA (5, 10, 20 and 40 mmol/l) in normal Ringer's solution (NRS). Mucosa exposed to HCl or LA (5, 10 and 20 mmol/l) in NRS (pH 1.5 and to a lesser extent pH 4.0) had a significant decrease in Isc and PD. Mucosa exposed to a high concentration of LA (40 mmol/l) in NRS (LRS) at pH 1.5 showed an increased G, but this increase was not significant. Values returned to baseline after solutions were returned to pH 7.0. Histological changes were consistent with HCl-induced (pH acid damage. HCl induced alteration in bioelectric properties of equine NG mucosa whereas addition of LRS did not, other than those changes seen with HCl alone.

  14. In vitro effects of hydrochloric acid and various concentrations of acetic, propionic, butyric, or valeric acids on bioelectric properties of equine gastric squamous mucosa.

    Science.gov (United States)

    Andrews, Frank M; Buchanan, Benjamin R; Smith, Sionagh H; Elliott, Sarah B; Saxton, Arnold M

    2006-11-01

    To compare the effects of hydrochloric acid (HCl) and various concentrations of volatile fatty acids (VFAs) on tissue bioelectric properties of equine stomach nonglandular (NG) mucosa. Gastric tissues obtained from 48 adult horses. NG gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference (PD) were measured and electrical resistance (R) and conductance calculated for tissues after addition of HCl and VFAs (5, 10, 20, and 40 mM) in normal Ringer's solution (NRS). Mucosa exposed to HCl in NRS (pH of 1.5 and, to a lesser extent, 4.0) had a significant decrease in Isc, PD, and R, whereas tissues exposed to acetic acid at a pH of acids at a pH of acid at a pH of acid at a pH of acid, in the presence of HCl at a pH of

  15. Influences of humic acid and fulvic acid on horizontal leaching behavior of anthracene in soil barriers.

    Science.gov (United States)

    Yu, Sheng; Li, Bang-Yu; Chen, Yi-Hu

    2015-12-01

    The influences of humic acid (HA) and fulvic acid (FA) on horizontal leaching behaviors of anthracene in barriers were investigated. Soil colloids (≤1 μm) were of concern because of their abilities of colloid-facilitated transport for hydrophobic organic compounds with soluble and insoluble organic matters. Through freely out of the barriers in the presence of soil colloids with FA added, the higher concentrations of anthracene were from 320 μg L(-1) (D1 and D3) to 390 μg L(-1) (D2 and D4) with 1 to 20 cm in length. The contents of anthracene were distributed evenly at 25 ng g(-1) dry weight (DW) (D1 and D3) and 11 ng g(-1) DW (D2 and D4) in barriers. Therefore, anthracene leaching behaviors were mainly induced by soil colloids with soluble organic matters. The insoluble organic matters would facilitate anthracene onto soil colloids and enhance the movement in and through porous media of soil matrix.

  16. A two-step leaching method designed based on chemical fraction distribution of the heavy metals for selective leaching of Cd, Zn, Cu, and Pb from metallurgical sludge.

    Science.gov (United States)

    Wang, Fen; Yu, Junxia; Xiong, Wanli; Xu, Yuanlai; Chi, Ru-An

    2018-01-01

    For selective leaching and highly effective recovery of heavy metals from a metallurgical sludge, a two-step leaching method was designed based on the distribution analysis of the chemical fractions of the loaded heavy metal. Hydrochloric acid (HCl) was used as a leaching agent in the first step to leach the relatively labile heavy metals and then ethylenediamine tetraacetic acid (EDTA) was applied to leach the residual metals according to their different fractional distribution. Using the two-step leaching method, 82.89% of Cd, 55.73% of Zn, 10.85% of Cu, and 0.25% of Pb were leached in the first step by 0.7 M HCl at a contact time of 240 min, and the leaching efficiencies for Cd, Zn, Cu, and Pb were elevated up to 99.76, 91.41, 71.85, and 94.06%, by subsequent treatment with 0.2 M EDTA at 480 min, respectively. Furthermore, HCl leaching induced fractional redistribution, which might increase the mobility of the remaining metals and then facilitate the following metal removal by EDTA. The facilitation was further confirmed by the comparison to the one-step leaching method with single HCl or single EDTA, respectively. These results suggested that the designed two-step leaching method by HCl and EDTA could be used for selective leaching and effective recovery of heavy metals from the metallurgical sludge or heavy metal-contaminated solid media.

  17. Kinetic study of the prehydrolysis of bagasse pith with hydrochloric acid in an agitated system

    Energy Technology Data Exchange (ETDEWEB)

    Villan Guerra, J.; Iglesias, R.G.; Lopez Planes, R.

    1981-01-01

    The hydrolysis of bagasse pith at 90-100 degrees with 0.25 N HCl gave sugar in 22% yield after 120 min. With 0.5 N HCl, the yield was 28% after 240 min. The specific constants of pentosan decomposition and of sugar formation were calculated, and the kinetic parameters (frequency factor, activation energy, and order of acid concentration) were determined. The pentosan decomposition constants were higher and the activation energies lower than literature values for hydrolysis with H/sub 2/SO/sub 4/.

  18. Copper Corrosion Under Non-uniform Magnetic Field in 0.5 M Hydrochloric Acid

    Science.gov (United States)

    Garcia-Ochoa, E.; Corvo, F.; Genesca, J.; Sosa, V.; Estupiñán, P.

    2017-05-01

    The influence of a magnetic field on the electrochemical reactions taking place at the surface of a copper electrode immersed in a 0.5 M HCl solution at room temperature has been studied. The symmetry axis of the magnetic field was lined up in the same direction of the ion flow to minimize the Lorentz forces. Measurements of potentiodynamic polarization curves, electrochemical impedance spectroscopy and electrochemical noise allow concluding that the magnetic field significantly affects the cathodic reactions, with corrosion rates increasing under the presence of oxygen in acid media and decreasing when oxygen is eliminated.

  19. Recovery of Iron from Pyrolusite Leaching Slag by a Lab-Scale Circulation Process of Oxalic Acid Leaching and Ultraviolet Irradiation

    Directory of Open Access Journals (Sweden)

    Biao Deng

    2017-12-01

    Full Text Available Pyrolusite leaching slag is a Fe-containing slag generated from pyrolusite leaching process with SO2. Recovery of iron from the slag not only has economic benefit, but also prevents the secondary pollution to the environment. A novel lab-scale cyclic process for recovering iron from pyrolusite leaching slag was introduced. The process contains two steps: (1 iron was leached with oxalic acid and [Fe(C2O4n](3−2n+ solution was generated; (2 the [Fe(C2O4n](3−2n+ solution was irradiated by ultraviolet and ferrous oxalate precipitation were obtained. The effect of operation parameter on leaching and irradiation process were studied separately. In the leaching process, the optimal solid/liquid ratio, oxalic acid concentration, leaching temperature, stirring rate, and leaching time are 1:50, 0.40 mol/L, 95 °C, 300 r/min, and 3 h, respectively. In the irradiation process, the best irradiation wavelength, Fe/oxalic acid molar ratio and irradiation time are 254 nm, 1:4, and 30 min. Besides, a test of 9 continuous cycles was carried out and the performance and material balance of the combined process were investigated. The results showed that the cyclic process is entirely feasible and prove to be stable producing, and ferrous oxalate of 99.32% purity. Material balance indicated that 95.17% of iron was recovered in the form of FeC2O4·2H2O, and the recovery efficiency of oxalic acid was 58.52%.

  20. Manganese ore tailing: optimization of acid leaching conditions and recovery of soluble manganese.

    Science.gov (United States)

    Santos, Olívia de Souza Heleno; Carvalho, Cornélio de Freitas; Silva, Gilmare Antônia da; Santos, Cláudio Gouvêa Dos

    2015-01-01

    Manganese recovery from industrial ore processing waste by means of leaching with sulfuric acid was the objective of this study. Experimental conditions were optimized by multivariate experimental design approaches. In order to study the factors affecting leaching, a screening step was used involving a full factorial design with central point for three variables in two levels (2(3)). The three variables studied were leaching time, concentration of sulfuric acid and sample amount. The three factors screened were shown to be relevant and therefore a Doehlert design was applied to determine the best working conditions for leaching and to build the response surface. By applying the best leaching conditions, the concentrations of 12.80 and 13.64 %w/w of manganese for the global sample and for the fraction -44 + 37 μm, respectively, were found. Microbeads of chitosan were tested for removal of leachate acidity and recovering of soluble manganese. Manganese recovery from the leachate was 95.4%. Upon drying the leachate, a solid containing mostly manganese sulfate was obtained, showing that the proposed optimized method is efficient for manganese recovery from ore tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Punica granatum leave extract as green corrosion inhibitor for mild steel in Hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Abboud Y.

    2013-09-01

    Full Text Available Leave of Punica granatum extract (LPGE as green inhibitor for the corrosion of mild steel in 1M HCl solution was studied using weight-loss and potentiodynamic polarization measurements. The results obtained revealed that LPGE has fairly good inhibiting properties for mild steel corrosion in 1M HCl solution, with efficiency of around 94 % at a concentration of 1 g/l. The inhibition was of a mixed anodic–cathodic nature. The film which is formed over the metal surface was analysed by FT-IR spectroscopy. Further examination using X-ray diffraction confirms the role of LPGE as an effective corrosion inhibitor for mild steel in acid media.

  2. An investigation on mechanism of acid drain in heap leaching structures.

    Science.gov (United States)

    Majdi, Abbas; Amini, Mehdi; Chermahini, Abotaleb Amini

    2009-06-15

    Gravelly drainage layer and semi-slotted polyethylene pipes are two main components of drainage system of heap leaching structures. Fluid is locally drained and directed to semi-slotted polyethylene pipes by gravelly drainage layer. Then, it is sent to a pregnant leach solution (PLS) pond by the semi-slotted polyethylene pipes gravitationally. In this paper, initially the existing relations, suggested for the design of drainage system of heap leaching structures, are analyzed. Then, the main differences between fluid drain in landfills and heap leaching structures are presented, and consequently, two new correction factors, named "replacement" and "delay" factors are suggested. The replacement factor illustrates the ratio of mean value of heap layers area to the acid-washed area and the delay factor represents the reduction of heap layers area. The new correction factors are added to Giroud equation and the modified format of the equation is suggested for computing gravelly drainage layer thickness of heap leaching structures. Also, these two correction factors are added to Majdi et al. equation and two new relations are suggested for determination of main and auxiliary drainage semi-slotted polyethylene pipes diameters in these structures. Finally, based on the new relations, adequate drainage systems are designed for two case studies ("Tarom" and "Sarcheshmeh 2" heap leaching structures) and the results are compared with those calculated by the exiting equations.

  3. Effect of acid leaching conditions on impurity removal from silicon doped by magnesium

    Directory of Open Access Journals (Sweden)

    Stine Espelien

    2017-07-01

    Full Text Available The effect of magnesium addition into a commercial silicon and its leaching refining behavior is studied for producing solar grade silicon feedstock. Two different levels of Mg is added into a commercial silicon and the leaching of the produced alloys by 10% HCl solution at 60 ℃ for different durations is performed. It is shown that the microstructure of the alloy and in particular the distribution of eutectic phases is dependent on the amount of the added Mg. Moreover, the metallic impurities in silicon such as Fe, Al, Ca and Ti are mainly forming silicide particles with different compositions. These silicides are physically more detached from the primary silicon grains and their removal through chemical and physical separation in leaching is better for higher Mg additions. It is observed that the leaching is more effective for the purification of smaller silicon particles produced from each Mg-doped silicon alloy. It is shown that acid leaching by the applied method is effective to reach more than 70% of phosphorous removal. It is also shown that the purity of silicon is dependent on the total Mg removal and effectiveness of leaching on removing the Mg2Si phase.

  4. Kinetics and mechanism of sphalerite leaching by sodium nitrate in sulphuric acid solution

    Directory of Open Access Journals (Sweden)

    Sokić M.

    2012-01-01

    Full Text Available Interest for application of hydrometallurgical processes in a processing of complex sulphide ores and concentrates has increased in recent years. Their application provides better metal recoveries and reduced emission of gaseous and toxic ageneses in the environment. The kinetics and mechanism of sphalerite leaching from complex sulphide concentrate with sulphuric acid and sodium nitrate solution at standard conditions was presented in this paper. The influences of temperature and time on the leaching degree of zinc were investigated and kinetic analysis of the process was accomplished. With temperature increasing from 60 to 90°C, the zinc leaching increased from 25.23% to 71.66% after 2 hours, i.e. from 59.40% to 99.83% after 4 hours. The selected kinetic model indicated that the diffusion through the product layer was the rate-controlling step during the sphalerite leaching. The activation energy was determined to be 55 kJ/mol in the temperature range 60-90°C. XRD, light microscopy and SEM/EDX analyses of the complex concentrate and leach residue confirmed formation of elemental sulphur and diffusion-controlled leaching mechanism.

  5. Bipolar membrane electrodialysis for generation of hydrochloric acid and ammonia from simulated ammonium chloride wastewater.

    Science.gov (United States)

    Li, Ya; Shi, Shaoyuan; Cao, Hongbin; Wu, Xinmin; Zhao, Zhijuan; Wang, Liying

    2016-02-01

    Simulated ammonium chloride wastewater was treated by a lab-scale bipolar membrane electrodialysis for the generation of HCl and NH3·H2O and desalination. The influence of initial concentration of NH4Cl, current density, salt solution volume, initial concentration of acid and base and membrane stack structure on the yields of HCl and NH3·H2O was investigated. The current efficiency and energy consumption were also examined under different conditions. The results showed that, at the current density of 48 mA/cm(2), the highest concentration of HCl and NH3·H2O with initial concentration of 110 g/L NH4Cl was 57.67 g/L and 45.85 g/L, respectively. Higher initial concentration of NH4Cl was favor to reduce unit energy consumption and increase current efficiency of the BMED system. The membrane stack voltage of BMED increased quickly under constant current when the concentration of NH4Cl contained in the solution of salt compartment was depleted below the "inflection point concentration" about 8000 mg/L. It means that the concentration of NH4Cl below 8000 mg/L was no longer suitable for BMED because of higher energy consumption. The HCl and NH3·H2O concentration increased more quickly following the increase of current density. When increasing the volume of NH4Cl, the concentration of HCl and NH3·H2O also increased. The high initial concentration of acid and base could improve the final concentration of them, while the growth rate was decreased. Compared with the BMED system with three compartments, the growth rate of HCl concentration with the two compartments was higher and its unit energy consumption was lower. It meant that the performance of the BMED system could be improved by optimizing operation conditions. The application feasibility of the generation of HCl and NH3·H2O and desalination of ammonium chloride wastewater by BMED was proved. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Impact of hydrochloric acid instillation on salvage of infected central venous catheters in children with acute lymphoblastic leukaemia.

    Science.gov (United States)

    Madsen, Mette; Rosthøj, Steen

    2013-01-01

    Bacteraemia associated with indwelling central venous catheters (CVC) causes significant morbidity in children with cancer. Hydrochloric acid (HCl) instillations have been reported to salvage CVCs with antibiotic-refractory infection. We implemented this treatment in 2002. The impact on the survival of CVCs has been evaluated in a retrospective cohort study of children with acute lymphoblastic leukaemia (ALL). Children with newly diagnosed ALL during 1999-2005 having their first CVC inserted before (n = 16) and after (n = 24) the introduction of the procedure were studied. All bacteraemic episodes were reviewed, recording bacteriological findings and treatment, and the time to premature or planned removal of the CVC was determined. In the comparison cohort, 31.0% (9/29) of bacteraemic episodes led to removal of the CVC, compared to 5.5% (2/36) in the intervention cohort (p = 0.01). Thus, the rate of catheter loss due to infection fell from 56.3% (9/16) to 8.3% (2/24) after introducing HCl treatment (p = 0.0025). Overall, the premature catheter removal rate fell from 75.0% (12/16) to 45.8% (11/24) (p = 0.10). Analysed in a CUSUM plot the reduced frequency of premature CVC removal evidently coincided with the introduction of the procedure. In a subgroup analysis of 21 monobacterial infections with coagulase-negative staphylococci, a decrease in systemic and lock antibiotic therapy was found. No adverse events were noted. HCl instillations significantly reduced the need to remove and replace CVCs. The procedure is practical, appears to be safe, and may reduce the consumption of antibiotics.

  7. Molecular simulation of aqueous electrolyte solubility. 3. Alkali-halide salts and their mixtures in water and in hydrochloric acid.

    Science.gov (United States)

    Moučka, Filip; Lísal, Martin; Smith, William R

    2012-05-10

    We extend the osmotic ensemble Monte Carlo (OEMC) molecular simulation method (Moučka et al. J. Phys Chem. B 2011, 115, 7849-7861) for directly calculating the aqueous solubility of electrolytes and for calculating their chemical potentials as functions of concentration to cases involving electrolyte hydrates and mixed electrolytes, including invariant points involving simultaneous precipitation of several solutes. The method utilizes a particular semigrand canonical ensemble, which performs simulations of the solution at a fixed number of solvent molecules, pressure, temperature, and specified overall electrolyte chemical potential. It avoids calculations for the solid phase, incorporating available solid chemical potential data from thermochemical tables, which are based on well-defined reference states, or from other sources. We apply the method to a range of alkali halides in water and to selected examples involving LiCl monohydrate, mixed electrolyte solutions involving water and hydrochloric acid, and invariant points in these solvents. The method uses several existing force-field models from the literature, and the results are compared with experiment. The calculated results agree qualitatively well with the experimental trends and are of reasonable accuracy. The accuracy of the calculated solubility is highly dependent on the solid chemical potential value and also on the force-field model used. Our results indicate that pairwise additive effective force-field models developed for the solution phase are unlikely to also be good models for the corresponding crystalline solid. We find that, in our OEMC simulations, each ionic force-field model is characterized by a limiting value of the total solution chemical potential and a corresponding aqueous concentration. For higher values of the imposed chemical potential, the solid phase in the simulation grows in size without limit.

  8. Effect of commercial fluoride dentifrices against hydrochloric acid in an erosion-abrasion model.

    Science.gov (United States)

    Passos, Vanara Florêncio; de Vasconcellos, Andréa Araújo; Pequeno, José Heriberto Pinheiro; Rodrigues, Lidiany Karla Azevedo; Santiago, Sérgio Lima

    2015-01-01

    This study assessed the effect of three commercial dentifrices with different fluoride-containing compounds in controlling the progression of dentin loss using an in vitro erosion-abrasion model. Dentin specimens were randomized into four groups (n = 10): control (no F), Elmex (1,400 ppm AmF), Meridol (1,400 ppm AmF/SnF2), and Crest Pro-Health (1,100 ppm SnF2). The dentin specimens were submitted to cycles of demineralization (HCl 0.01 M for 60 s), remineralization (artificial saliva for 60 min), and immersion in 1:3 w/w of dentifrice/artificial saliva, followed by toothbrushing (150 brushing strokes). The cycle was repeated three times daily for 5 days. Surface loss was quantified by stylus profilometry. Data were submitted to one-way ANOVA and Tukey's tests (p acid damage. However, the beneficial effect of different fluorides present in commercial dentifrices is questionable. Thus, a determination of an effective fluoride dentifrice may be beneficial in the reduction of the erosive process in patients with gastric disorders.

  9. Formation of Hydrogen-Ion in Isomolar Solution of Hydrochloric and Hydrobromic Acids and Their Salts

    Directory of Open Access Journals (Sweden)

    M.A. Kovaleva

    2016-09-01

    Full Text Available Despite the presence of a large amount of factual material on thermodynamic parameters of complexation of agents in different solvents, including mixed ones, obtained knowledge is specific in nature. In order to identify more general patterns, studies are relevant that would allow to interpret the obtained data taking into account the interaction between chemical forms in solutions. This paper presents a general approach to studying weak ionic interactions in solutions that allows to simultaneously determine the constants of these interactions and the parameters characterizing the influence of changes in the ionic environment on these constants by the example of chlorides and bromides of alkali metals. The obtained constants for hydrosulfate-ion formation and the imperfection parameters can be a reference material for more accurate calculation of the concentration of hydrogen ions in sulfuric acid solutions. The developed approach and patterns identified in the work can be used to study the balanced states for formation of low and medium stable complexes.

  10. Acid leaching of coal: to produce clean fuels from Turkish lignite

    Energy Technology Data Exchange (ETDEWEB)

    Seferinoglu, Meryem [Mineral Research and Exploration Directorate (Turkey)], email: meryem_seferinoglu66@yahoo.com; Duzenli, Derya [Ankara Central Laboratory (Turkey)

    2011-07-01

    With the increasing concerns about the environment, energy producers and governments are looking at developing clean energy sources. However, Turkey has limited clean energy resources and is using low grade coal which has high sulphur content as an alternative energy source. The aim of this paper is to study the possibility of generating clean fuel from Edirne Lignite and to get a better understanding of chemical mechanisms involved in coal leaching with hydrofluoric acid (HF) solutions. Leaching was conducted on Edirne Lignite with HF solution at ambient temperature and the effects of parameters such as reaction time and concentration of acid solutions on the process were evaluated. The optimum conditions were found and it was shown that ash levels can be reduced from 28.9% to 10.5% and the calorific value increased by 500kcal/kg with the HF leaching method. This study demonstrated that the production of clean fuel from high sulphur lignite is possible.

  11. Impact of simulated acid rain on trace metals and aluminum leaching in latosol from Guangdong Province, China

    Science.gov (United States)

    Jia-En Zhang; Jiayu Yu; Ying Ouyang; Huaqin. Xu

    2014-01-01

    Acid rain is one of the most serious ecological and environmental problems worldwide. This study investigated the impacts of simulated acid rain (SAR) upon leaching of trace metals and aluminum (Al) from a soil. Soil pot leaching experiments were performed to investigate the impacts of SAR at five different pH levels (or treatments) over a 34-day period upon the...

  12. Preservation of urine free catecholamines and their free O-methylated metabolites with citric acid as an alternative to hydrochloric acid for LC-MS/MS-based analyses.

    Science.gov (United States)

    Peitzsch, Mirko; Pelzel, Daniela; Lattke, Peter; Siegert, Gabriele; Eisenhofer, Graeme

    2016-01-01

    Measurements of urinary fractionated metadrenalines provide a useful screening test to diagnose phaeochromocytoma. Stability of these compounds and their parent catecholamines during and after urine collection is crucial to ensure accuracy of the measurements. Stabilisation with hydrochloric acid (HCl) can promote deconjugation of sulphate-conjugated metadrenalines, indicating a need for alternative preservatives. Urine samples with an intrinsically acidic or alkaline pH (5.5-6.9 or 7.1-8.7, respectively) were used to assess stability of free catecholamines and their free O-methylated metabolites over 7 days of room temperature storage. Stabilisation with HCl was compared with ethylenediaminetetraacetic acid/metabisulphite and monobasic citric acid. Catecholamines and metabolites were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Free catecholamines and their O-methylated metabolites were stable in acidic urine samples over 7 days of room temperature storage, independent of the presence or absence of any stabilisation method. In contrast, free catecholamines, but not the free O-methylated metabolites, showed rapid degradation within 24 h and continuing degradation over 7 days in urine samples with an alkaline pH. Adjustment of alkaline urine samples to a pH of 3-5 with HCl or 4.8-5.4 with citric acid completely blocked degradation of catecholamines. Ethylenediaminetetraacetic acid/metabisulphite, although reducing the extent of degradation of catecholamines in alkaline urine, was largely ineffectual as a stabiliser. Citric acid is equally effective as HCl for stabilisation of urinary free catecholamines and minimises hazards associated with use of strong inorganic acids while avoiding deconjugation of sulphate-conjugated metabolites during simultaneous LC-MS/MS measurements of free catecholamines and their free O-methylated metabolites.

  13. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    Science.gov (United States)

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  14. The bioavailability of sulpiride taken as a film-coated tablet with sodium bicarbonate, cimetidine, natural orange juice or hydrochloric acid.

    Science.gov (United States)

    Shinkuma, D; Hamaguchi, T; Kobayashi, M; Yamanaka, Y; Mizuno, N

    1989-10-01

    The bioavailability of sulpiride taken in film-coated tablet form with sodium bicarbonate or cimetidine or with natural orange juice or diluted hydrochloric acid was studied. A commercial sulpiride film-coated tablet (100 mg/T) treated with polyvinylacetal diethylaminoacetate (AEA), which remain undissolved at pH above 4-5, was given to four healthy volunteers who had fasted overnight. The subjects were divided into two groups, those showing high and low bioavailability of sulpiride from an AEA film-coated tablet. The two high bioavailability subjects took one tablet (100 mg) with 100 ml of water (1) alone, (2) together with 1 g of sodium bicarbonate or (3) during concurrent dosing with cimetidine, 200 mg three times a day. The two low bioavailability subjects swallowed one tablet with 100 ml of (1) water, (2) natural orange juice, or (3) diluted hydrochloric acid. Urine samples were collected over a 48-h period following sulpiride administration to determine sulpiride concentrations by HPLC. The bioavailability was estimated from the cumulative amount excreted unchanged in urine over 48 h (Du48). In the high bioavailability subjects, the bioavailability of sulpiride markedly decreased with the coadministration of sodium bicarbonate or cimetidine compared to when the tablet was taken alone. In the low bioavailability subjects, the bioavailability remarkably increased with the concomitant intake of orange juice or diluted hydrochloric acid over that with only water. These results suggest that the bioavailability of sulpiride from AEA film-coated tablet is influenced by the individual's gastric acidity and by coadministered drug and drink which affect gastric acidity.

  15. Leaching of Glyphosate and Aminomethylphosphonic Acid from an Agricultural Field over a Twelve-Year Period

    DEFF Research Database (Denmark)

    Norgaard, Trine; Moldrup, Per; Ferré, Ty P A

    2014-01-01

    The globally-used herbicide glyphosate (N-(phosphonomethyl)glycine) and its most frequently detected metabolite, aminomethylphosphonic acid (AMPA), were studied in a unique 12-year field-scale monitoring program. The leaching of glyphosate, AMPA, and soil particles were studied in a shallow...... intensity and the timing of rain events after glyphosate application....

  16. Distribution of heavy metal pollution in sediments from an acid leaching site of e-waste.

    Science.gov (United States)

    Quan, Sheng-Xiang; Yan, Bo; Lei, Chang; Yang, Fan; Li, Ning; Xiao, Xian-Ming; Fu, Jia-Mo

    2014-11-15

    The spatial distribution, bioavailability, potential risks and emission sources of 12 heavy metals in sediments from an acid leaching site of e-waste were investigated. The results showed that the sediments from the acid leaching site were significantly contaminated with Cu, Zn, Cd, Sn, Sb and Pb, especially in the middle sediments (30-50 cm), with average concentrations of 4820, 1260, 10.7, 2660, 5690 and 2570 mg/kg, respectively. Cu, Cd and Pb were mainly present in the non-residual fractions, suggesting that the sediments from the acid leaching site may exert considerable risks. Mn, Ni, Zn, Sn and Sb were predominantly associated with the residual fraction. Despite their low reactivity and bioavailability, uncommon pollutants, such as Sn and Sb, may exert environmental risks due to their extremely elevated total concentrations. All of these results indicate that there is an urgent need to control the sources of heavy metal emission and to remediate contaminated sediments. In addition to Ni, Cu, Zn, Cd and Pb, the sediments from an acid leaching site in Guiyu were heavily polluted with uncommon heavy metal pollutants, such as Sn and Sb. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. KINETIC STUDY ON ADSORPTION OF CHROMIUM(lIl TO DIATOMACEOUS EARTH PRE-TREATED WITH SULFURIC AND HYDROCHLORIC ACIDS

    Directory of Open Access Journals (Sweden)

    Nuryono Nuryono

    2010-06-01

    Full Text Available In this research, the effect of Sangiran diatomaceous earth pre-treatment with sulfuric acid (H2SO4 and hydrochloric acid (HCl on the kinetics of adsorption for Cr(III in aqueous solution has been studied. The research has been carried out by mixing an amount of diatomeaeous earth with HCl or H2SO4 in various concentrations for two hours at temperature of 150 - 200°C. The mixture was washed with water until neutral, and the residue was dried at 70°C for four hours. The result then was used as adsorbent. Adsorption was carried out by mixing an amount of adsorbent with Cr(III solution in various contact times. Ion adsorbed was determined by analyzing filtrate using atomic absorption spectrophotometry. The effect of pre-treatment on adsorption kinetics was evaluated based on kinetic parameters, i.e. constant of adsorption rate by using Langmuir-Hinshelwood kinetics and using two-process kinetics (fast and slow processes. Adsorption kinetics calculated using LH equation gave negative value for adsorption rate constant of zero order (k0. On the other words, the LH kinetics might not be applied for adsorption of Cr(III to diatomaceous earth adsorbent. Results of kinetics study approached using two processes (fast and slow showed that adsorption of Cr(III occurred in two processes with rate constant of fast adsorption, kc, 0.041/min, rate constant of slow adsorption, kl, 0.0089/min, and of slow desorption, k'l, 0.089/menit. Pre-treatment with HCl up to 10 M decreased either kc, kl or k'l, while pre-treatment with H2SO4 1M increased kc to 0.061/min, decreased kl to 0.00424 and k'l to 0.0139/min. On pre-treatment with H2SO4 higher than 6 M significantly decreased three constants above. Based on the Gibbs energy change (4.31 - 6.79 kJ/mole showed that adsorption involved physical interaction.   Keywords: adsorption, chromium, diatomaceous earth, kinetics, Langmuir-Hinshelwood

  18. Study on copper kinetics in processing sulphide ore mixed with copper and zinc with sulfuric acid leaching under pressure

    Science.gov (United States)

    Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

    2018-01-01

    Sulphide ore mixed with copper and zinc is processed with pressure acid leaching. Research is conducted on the copper kinetic. The stirring rate is set at 600 rpm which could eliminate the influence of external diffusions. Research is conducted on the factors affecting the copper leaching kinetic are temperature, pressure, concentration of sulfuric acid, particle size. The result shows that the apparent activity energy is 50.7 KJ/mol. We could determine that the copper leaching process is shrinking core model of chemical reaction control and work out the leaching equation.

  19. Experimental Study and Reactive Transport Modeling of Boric Acid Leaching of Concrete

    Directory of Open Access Journals (Sweden)

    Chiang K.-T. K.

    2013-07-01

    Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure, compromise the integrity of the structure, or cause unmonitored releases of contaminated water to the environment. Experimental data indicate that pH is a critical parameter that determines the corrosion susceptibility of rebar in borated water and the degree of concrete degradation by boric acid leaching. In this study, reactive transport modeling of concrete leaching by borated water was performed to provide information on the solution pH in the concrete crack or matrix and the degree of concrete degradation at different locations of an SFP concrete structure exposed to borated water. Simulations up to 100 years were performed using different boric acid concentrations, crack apertures, and solution flow rates. Concrete cylinders were immersed in boric acid solutions for several months and the mineralogical changes and boric acid penetration in the concrete cylinder were evaluated as a function of time. The depths of concrete leaching by boric acid solution derived from the reactive transport simulations were compared with the measured boric acid penetration depth.

  20. Particulates in hydrometallurgy: Part I. Characterization of laterite acid leach residues

    Science.gov (United States)

    Briceno, A.; Osseo-Asare, K.

    1995-02-01

    Two different laterite samples, designated as Ore No. 1 and Ore. No. 2, respectively, were leached with sulfuric acid in the temperature range of 25°C to 275°C, in order to evaluate the effects of ore type and leaching conditions ( e.g., temperature and solid/liquid ratio) on the settling behavior of the leach residues. The initial solids, as well as the leach residues, were characterized by chemical and physical techniques such as X-ray diffraction, electrophoretic mobility, particle size, and chemical analyses. Spectrochemical and X-ray analyses determined that Ore No. 1 was a limonitic-type (iron oxide-rich ore) material, whereas Ore No. 2 was a transitional laterite ore (silicate-rich, iron oxidecontaining material). By means of X-ray diffraction analysis, it was found that the conversion of goethite to hematite was enhanced as the temperature and/or leaching time was increased. Moreover, it was determined by chemical analysis that as the leaching temperature increased, the concentrations of Ni and Co progressively increased in solution, whereas the impurities (Fe and Al) rose through a maximum and then decreased. This behavior is attributed to the reprecipitation of iron and aluminum from solution as hydrolysis products of hematite and aluminum sulfates. The particle size studies revealed a particle size growth with temperature increase, which is attributed to the deposition of reprecipitation products onto the surface of the solid residues. Investigations of the surface chemistry of the coated particles via the electrophoretic mobility technique revealed that the 275°C leach residues (Ore No. 2, pzc ˜2) exhibited a point of zero charge (pzc) near pH 2, which is probably due to the redeposition of the dissolved silica. In contrast, the 250°C leach residues (Ore No. 1, iron oxide-rich ore, pzc˜2) had a pzc value of about 3.8. This shift in mobility to less acidic values suggests that in this case, the insoluble iron and aluminum oxide products on the

  1. Acid leaching of uranium present in a residue from mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Braulio, Walace S.; Ladeira, Ana C.Q. [Center for Development of Nuclear Technology (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Dept. of Mineral Technology

    2011-07-01

    The acid mine drainage is one of the most important environmental problems associated with mining of ores containing sulfides. The treatment of these acid effluents, which contains high concentrations of dissolved metals and anions, is generally by liming. The wastes generated in the liming process may present significant toxicity and their storage in inappropriate places waiting for treatment is a common issue that requires solution. Osamu Utsumi Mine located in the city of Caldas, Minas Gerais, has been facing this problem. The residue of this mine consists of an alkaline sludge generated from the neutralization of the pH of acid mine drainage and is rich in various metals, including uranium. The main concern is the long term stability of this residue, which is in permanent contact with the acid water in the open pit. The recovery of uranium by hydrometallurgical techniques, such as acid leaching, can be a viable alternative on the reuse of this material. This study aimed at establishing a specific leaching process for the recovery of uranium present in the sludge from Caldas uranium mine. Some parameters such as solid/liquid ratio (0.09 to 0.17), time of leaching (1 to 24 hours) and concentration of sulfuric acid (pH from 0 to 3.0) were assessed. The results showed that it is possible to extract 100% of uranium present in the sludge. The concentration of U{sub 3}O{sub 8} in the residue was 0.25%, similar to the content of the vein ores which is around 0.20% to 1.0%. The best experimental leaching condition is solid/liquid ratio of 0.17, pH 1.0 and 2 hours of reaction at room temperature (25 deg C). The content of uranium in the liquor is around 440 mgL{sup -1}. The recovery of the uranium from the liquor is under investigation by ionic exchange. (author)

  2. Effects of acid leaching aluminum from reservoir bottom sediment ...

    African Journals Online (AJOL)

    user

    2011-03-14

    Mar 14, 2011 ... suspended sediment concentration by acoustic equations for soil sediment. Afr. J. Biotechnol. 9(2): 170-177. Mosquera AC (1990). Comparison of indirect methods for the determination of percent exchangeable aluminium in acid soils of. Galicia (NW Spain). Commun. Soil Sci. Plant Anal. 21(5-6): 365-375.

  3. Bypass flow and its role in leaching of raised beds under different land use types on an acid sulphate soil.

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Booltink, H.W.G.; Mensvoort, van M.E.F.; Bouma, J.

    1997-01-01

    A better understanding of leaching processes in raised beds is useful in assessing management options for acid sulphate soils. Field and laboratory studies were carried out to quantify the effects of soil physical properties and bypass flow on leaching processes of new, 1-year-old and 2-year-old

  4. Inhibition Behaviour of Some Isonicotinic Acid Hydrazides on the Corrosion of Mild Steel in Hydrochloric Acid Solution

    Directory of Open Access Journals (Sweden)

    M. P. Chakravarthy

    2013-01-01

    Full Text Available New corrosion inhibitors, namely, isonicotinic acid (1H-indol-3-yl-methylenehydrazide (INIMH and isonicotinic acid (1H-pyrrol-2-yl-methylenehydrazide (INPMH, have been synthesized, and their inhibitive characteristics for the corrosion of mild steel in 0.5 M HCl were investigated by mass loss and electrochemical techniques. The structures of the synthesized compounds were confirmed using spectral studies. Potentiodynamic polarization studies revealed that the investigated inhibitors are of mixed type. Various thermodynamic parameters were evaluated. Langmuir adsorption isotherm was found to be the best description for both inhibitors. FTIR spectra, energy dispersive X-ray spectroscopy (EDX, and scanning electron microscopy (SEM were performed to characterize the passive film on the metal surface.

  5. Polyvinyl alcohol–sulphanilic acid water soluble composite as corrosion inhibitor for mild steel in hydrochloric acid medium

    Directory of Open Access Journals (Sweden)

    M. Srimathi

    2014-11-01

    Full Text Available The inhibitive action of synthesised polyvinyl alcohol–sulphanilic acid (PVASA composite on the corrosion of commercial mild steel in 1 M HCl medium has been investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopic (EIS methods. Characterization of PVASA composite has been carried out using Fourier transform infrared spectroscopy (FTIR. Experimental results reveal that PVASA composite acts as an inhibitor in the acid environment. The inhibition efficiency increases with an increase in the concentration of the inhibitor. Maximum inhibition efficiency of PVASA composite was found to be 84% at 6000 ppm. Thermodynamic and kinetic parameters have been obtained from temperature studies. Electrochemical measurement reveals that PVASA composite acts as a mixed inhibitor and the adsorption follows Langmuir adsorption isotherm.

  6. Adsorption and corrosion inhibition of carbon steel in hydrochloric acid medium by hexamethylenediamine tetra(methylene phosphonic acid

    Directory of Open Access Journals (Sweden)

    M.R. Laamari

    2016-09-01

    Full Text Available The inhibitive effect of the hexamethylenediamine tetra(methylene phosphonic acid (HMDTMPA on the corrosion of carbon steel in 1.0 M HCl solution has been investigated by weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS techniques. The presence of (HMDTMPA reduces remarkably the corrosion rate of carbon steel in acidic solution. The effect of temperature on the corrosion behavior of carbon steel was studied in the range of 298–328 K. Results clearly reveal that the (HMDTMPA behaves as a mixed type corrosion inhibitor with the highest inhibition at 4 × 10−3 M. The adsorption of HMDTMPA on the carbon steel surface obeys to the Langmuir’s adsorption isotherm. Surface analysis via scanning electron microscope (SEM shows a significant improvement on the surface morphology of the carbon steel plate.

  7. A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover.

    Science.gov (United States)

    Li, Wenzhi; Liu, Qiyu; Ma, Qiaozhi; Zhang, Tingwei; Ma, Longlong; Jameel, Hasan; Chang, Hou-Min

    2016-11-01

    A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Extraction of gold(III) from hydrochloric acid solutions by CTAB/n-heptane/iso-amyl alcohol/Na2SO3 microemulsion.

    Science.gov (United States)

    Lu, Wenjuan; Lu, Yanmin; Liu, Fei; Shang, Kai; Wang, Wei; Yang, Yanzhao

    2011-02-28

    The extraction of Au(III) from hydrochloric acid solutions by microemulsion was studied. The extraction experiments were carried out using cetyltrimethylammonium bromide (CTAB) as surfactant and iso-amyl alcohol as co-surfactant. Au(III) was found to be extracted into the microemulsion phase due to ion pair formation such as AuCl(4)(-)CTAB(+). The influence of temperature on the extraction of Au(III) has been investigated at temperatures ranging from 288 to 313 K. Temperature was found to decrease the distribution of Au(III). Thermodynamic parameters like enthalpy and entropy of the extraction, calculated by applying Van't Hoff equation, were -36.76 kJ mol(-1) and -84.87 J mol(-1) K(-1), respectively. Furthermore, the influence of the concentrations of hydrogen ion and chloride anion on the extraction efficiency (E%) were verified. Au(III) was extracted quantitatively (E%>99%) and selectively at the whole range of HCl concentrations (0.2-5 M). Recovery of gold from electrical waste and treatment of CTAB wastewater generated from the extraction were also discussed. Thus, the extraction of Au(III) from hydrochloric acid solutions by microemulsion is an effective approach. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Speciation analysis of Sb(III) and Sb(V) in antileishmaniotic drug using Dowex 1 x 4 resin from hydrochloric acid solution.

    Science.gov (United States)

    Łukaszczyk, L; Zyrnicki, W

    2010-09-05

    A new and simple method for the direct and simultaneous determination of Sb(III) and Sb(V) in meglumine antimoniate, the first-choice drug for leishmaniasis treatment, was developed. Speciation analysis was carried out using the quantitative separation of inorganic trivalent and pentavalent antimony on Dowex 1 x 4 resin from 1.5 mol l(-1) hydrochloric acid solution. The inductively coupled plasma optical emission spectrometry (ICP-OES) was used for determination of antimony. The interfering effects of As, Bi, Cd, Cu, Mn, Pb and Zn were examined and only Bi was found to be a significant interferent. The liberation of Sb(V) and Sb(III) from organoantimonial compounds without changing of oxidation state was carried out by means of 1.5 mol l(-1) hydrochloric acid solution. The spike recovery values obtained for Sb(III) in pharmaceutical sample varied from 92 to 100%. The method was successfully applied for the direct determination of antimony(III) and of antimony(V) in meglumine antimoniate. 2010 Elsevier B.V. All rights reserved.

  10. Electrochemical and theoretical studies on the synergistic interaction and corrosion inhibition of alkyl benzimidazoles and thiosemicarbazide pair on mild steel in hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Ramya, K.; Mohan, Revathi; Anupama, K.K.; Joseph, Abraham, E-mail: drabrahamj@gmail.com

    2015-01-15

    Synergistic hydrogen bonded interaction of alkyl benzimidazoles and thiosemicarbazide (TSC) and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E{sub HOMO}, E{sub LUMO} and gap energy (ΔE) thiosemicarbazide (TSC) interacts with benzimidazoles derivatives up to a bond length of approximately 1.99Å. This interaction represents the formation of a hydrogen bond between the thiosemicarbazide (TSC) and benzimidazoles. This synergistic interaction of thiosemicarbazide (TSC) and benzimidazole derivatives offer extended inhibition efficiency towards mild steel in hydrochloric acid. - Highlights: • Synergistic interaction between alkyl benzimidazoles and TSC has been studied. • Mechanism involves combination of physisorption and chemisorption. • The adsorption phenomenon obeys Langmuir isotherm. • Inhibition efficiency increases with temperature.

  11. Behaviour of Silica during Metal Recovery from Bauxite Residue by Acidic Leaching

    OpenAIRE

    Marin Rivera, Rodolfo; Ulenaers, Brecht; Ounoughene, Ghania; Binnemans, Koen; Van Gerven, Tom

    2017-01-01

    Bauxite residue represents an interesting source for not only major elements such as aluminium, iron and titanium, but also for rare earths (REEs), while the residue after metal recovery can be used for low-carbon building materials and cementitious binders. Several methods based on direct acidic leaching for recovering metals from bauxite residue have been reported. The co-dissolution of iron represents a significant drawback for REEs recovery upon silica polymerization. The behaviour of sil...

  12. Antimony leaching in plastics from waste electrical and electronic equipment (WEEE) with various acids and gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tostar, Sandra, E-mail: sandra.tostar@chalmers.se [Department of Industrial Materials Recycling, Chalmers University of Technology, 412 96 Gothenburg (Sweden); Stenvall, Erik; Boldizar, Antal [Department of Material and Manufacturing Technology, Chalmers University of Technology, 412 96 Gothenburg (Sweden); Foreman, Mark R. St. J. [Department of Industrial Materials Recycling, Chalmers University of Technology, 412 96 Gothenburg (Sweden)

    2013-06-15

    Highlights: • We have proposed a method to recover antimony from electronic plastics. • The most efficient acid solution was sodium hydrogen tartrate in dimethyl sulfoxide. • Gamma irradiation did not influence the antimony leaching ability. - Abstract: There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5 M) dissolved in either dimethyl sulfoxide or water (at ca. 23 °C and heated to ca. 105 °C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed.

  13. Ethanol-based organosolv treatment with trace hydrochloric acid improves the enzymatic digestibility of Japanese cypress (Chamaecyparis obtusa) by exposing nanofibers on the surface.

    Science.gov (United States)

    Hideno, Akihiro; Kawashima, Ayato; Endo, Takashi; Honda, Katsuhisa; Morita, Masatoshi

    2013-03-01

    The effects of adding trace acids in ethanol based organosolv treatment were investigated to increase the enzymatic digestibility of Japanese cypress. A high glucose yield (60%) in the enzymatic hydrolysis was obtained by treating the sample at 170 °C for 45 min in 50% ethanol liquor containing 0.4% hydrochloric acid. Moreover, the enzymatic digestibility of the treated sample was improved to ∼70% by changing the enzyme from acremonium cellulase to Accellerase1500. Field emission scanning electron microscopy revealed the presence of lignin droplets and partial cellulose nanofibers on the surface of the treated sample. Simultaneous saccharification and fermentation of the treated samples using thermotolerant yeast (Kluyveromyces marxianus NBRC1777) was tested. A high ethanol concentration (22.1 g/L) was achieved using the EtOH50/W50/HCl0.4-treated sample compared with samples from other treatments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Extraction of Sm(IIIand Nd(III with N,N,N’,N’-tetrabutyl-3-oxy-diglycolamidefrom hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Yang J.H.

    2013-01-01

    Full Text Available The extraction behavior of Sm(III and Nd(III with N,N,N’,N’-tetrabutyl-3-oxa-diglycolamide (TBDGA in 70% kerosene-30% n-octanol from hydrochloride acid wasstudied. The effect of hydrochloric acid concentration, extractant concentration,and temperature on the distribution of rare earth elementswas investigated. The extraction mechanism was established and the stoichiometry of the main extracted species was confirm to be SmCl3•2TBDGA and NdCl3•2TBDGA for Sm(III and Nd(III, respectively. The extraction distribution ratio decreases with an increase in temperature, which demonstrates that the extraction reaction is exothermic. The IR spectra of the loaded organic phase and free extractant were recorded and discussed.

  15. Dolomite phosphate rock (DPR) application in acidic sandy soil in reducing leaching of phosphorus and heavy metals-a column leaching study.

    Science.gov (United States)

    Yang, Yuangen; He, Zhenli; Yang, Xiaoe; Stoffella, Peter J

    2013-06-01

    A column leaching study was designed to investigate the leaching potential of phosphorus (P) and heavy metals from acidic sandy soils applied with dolomite phosphate rock (DPR) fertilizers containing varying amounts of DPR material and N-Viro soils. DPR fertilizers were made from DPR materials mixing with N-Viro soils at the ratios of 30, 40, 50, 60, and 70 %, and applied in acidic sandy soils at the level of 100 mg available P per kilogram soil. A control and a soluble P chemical fertilizer were also included. The amended soils were incubated at room temperature with 70 % field water holding capacity for 21 days before packed into a soil column and subjected to leaching. Seven leaching events were conducted at days 1, 3, 7, 14, 28, 56, and 70, respectively, and 258.9 mL of deionized water was applied at each leaching events. The leachate was collected for the analyses of pH, electrical conductivity (EC), dissolved organic carbon (DOC), major elements, and heavy metals. DPR fertilizer application resulted in elevations up to 1 unit in pH, 7-10 times in EC, and 20-40 times in K and Ca concentrations, but 3-10 times reduction in P concentration in the leachate as compared with the chemical fertilizer or the control. After seven leaching events, DPR fertilizers with adequate DPR materials significantly reduced cumulative leaching losses of Fe, P, Mn, Cu, and Zn by 20, 55, 3.7, 2.7, and 2.5 times than chemical fertilizer or control. Even though higher cumulative losses of Pb, Co, and Ni were observed after DPR fertilizer application, the loss of Pb, Co, and Ni in leachate was <0.10 mg (in total 1,812 mL leachate). Significant correlations of pH (negative) and DOC (positive) with Cu, Pb, and Zn (P<0.01) in leachate were observed. The results indicated that DPR fertilizers had a great advantage over the soluble chemical fertilizer in reducing P loss from the acidic sandy soil with minimal likelihood of heavy metal risk to the water environment. pH elevation and high

  16. Particulates in hydrometallurgy: Part III. Dewatering behavior of flocculated laterite acid leach residues

    Science.gov (United States)

    Briceno, A.; Osseo-Asare, K.

    1995-02-01

    Three polyacrylamide-based polymers of different chemical properties (polymer A, 34 pct anionic, 11×106 mol wt; polymer B, 7 pct anionic, 7.5×106 mol wt; polymer C, nonionic, 13.5×106 mol wt) were used to evaluate the flocculation behavior of laterite acid leach residues. The solid-liquid separation characteristics of the leach residues were investigated with the aid of settling rate, supernatant turbidity, and slurry filtrability measurements. The polymeric flocculants were found to be effective in improving the dewatering properties of the acid leach residues. Polymer effectiveness increased with increasing polymer dosage for all the polymers, but an optimum polymer dose was only found for polymer A (34 pct anionic, 11×106 mol wt) in the studied range of polymer addition. Similarly, the dewatering behavior was improved at higher polymer molecular weight. In addition, it was found that the flocculation performance was adversely affected by an increase in the degree of polymer hydrolysis which, in turn, increases the ratio of carboxylic to amide functional groups in the polymer chain. Polymer C (nonionic ˜0 pct hydrolysis, 13.5×106 mol wt) was found to be the most efficient flocculant in terms of all the performance criteria investigated. The preceding results were rationalized in terms of bridging flocculation, the ionization and molecular configuration of the polymers, hydrogen bonding, and the solid/aqueous interfacial charge.

  17. Copper solvent extraction from chalcopyrite concentrate acid leach solutions by LIX 984

    Directory of Open Access Journals (Sweden)

    Elamari K.

    2006-01-01

    Full Text Available Copper production from ores or sulphide concentrates is classically realized by pyrometallurgical route. In this study, hydrometallurgical treatment of a copper sulphide concentrate, provided by Hajar Mine (ONA-Group, Morocco, was tested by using a mixture of nitric and hexafluorosilicic acids. Copper is present in the solid product as chalcopyrite and its amount is 28.1 % by weight. Leaching stage allows to dissolve more than 90% of copper witch is accompanied, in the same averages, by Zn and Fe. The leach solution obtained has pH = 0.6 and Eh = 580 mV/ENH and contains 19.3 g/L Cu, 18.1 g/L Fe, 4.5 g/L Zn and 0.03 g/L Pb. The recovery of copper from this leach solution was curried out by solvent extraction using Lix 984, diluted in Escaid 110. McCabe - Thiele distribution isotherms showed that at pH 1.7 total and selective copper extraction can be realized with Øo:Øa =1.5:1 in 3 extraction stages. Stripping of the loaded copper by treating the organic phases was easily obtained by a sulphuric acid solution.

  18. A statistical approach to the experimental design of the sulfuric acid leaching of gold-copper ore

    Directory of Open Access Journals (Sweden)

    Mendes F.D.

    2003-01-01

    Full Text Available The high grade of copper in the Igarapé Bahia (Brazil gold-copper ore prevents the direct application of the classic cyanidation process. Copper oxides and sulfides react with cyanides in solution, causing a high consumption of leach reagent and thereby raising processing costs and decreasing recovery of gold. Studies have showm that a feasible route for this ore would be a pretreatment for copper minerals removal prior to the cyanidation stage. The goal of this experimental work was to study the experimental conditions required for copper removal from Igarapé Bahia gold-copper ore by sulfuric acid leaching by applying a statistical approach to the experimental design. By using the Plackett Burman method, it was possible to select the variables that had the largest influence on the percentage of copper extracted at the sulfuric acid leaching stage. These were temperature of leach solution, stirring speed, concentration of sulfuric acid in the leach solution and particle size of the ore. The influence of the individual effects of these variables and their interactions on the experimental response were analyzed by applying the replicated full factorial design method. Finally, the selected variables were optimized by the ascending path statistical method, which determined the best experimental conditions for leaching to achieve the highest percentage of copper extracted. Using the optimized conditions, the best leaching results showed a copper extraction of 75.5%.

  19. Effect of key parameters on the selective acid leach of nickel from mixed nickel-cobalt hydroxide

    Science.gov (United States)

    Byrne, Kelly; Hawker, William; Vaughan, James

    2017-01-01

    Mixed nickel-cobalt hydroxide precipitate (MHP) is a relatively recent intermediate product in primary nickel production. The material is now being produced on a large scale (approximately 60,000 t/y Ni as MHP) at facilities in Australia (Ravensthorpe, First Quantum Minerals) and Papua New Guinea (Ramu, MCC/Highlands Pacific). The University of Queensland Hydrometallurgy research group developed a new processing technology to refine MHP based on a selective acid leach. This process provides a streamlined route to obtaining a high purity nickel product compared with conventional leaching / solvent extraction processes. The selective leaching of nickel from MHP involves stabilising manganese and cobalt into the solid phase using an oxidant. This paper describes a batch reactor study investigating the timing of acid and oxidant addition on the rate and extent of nickel, cobalt, manganese leached from industrial MHP. For the conditions studied, it is concluded that the simultaneous addition of acid and oxidant provide the best process outcomes.

  20. Succinic acid-based leaching system: A sustainable process for recovery of valuable metals from spent Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li; Qu, Wenjie; Zhang, Xiaoxiao; Lu, Jun; Chen, Renjie; Wu, Feng; Amine, Khalil

    2015-05-01

    A hydrometallurgical method involving natural organic acid leaching has been developed for recovery of lithium and cobalt from the cathode active materials in spent lithium-ion batteries. Succinic acid is employed as leaching agent and H2O2 as reductant. The cobalt and lithium contents from the succinic acid-based treatment of spent batteries are determined by inductively coupled plasma-optical emission spectroscopy to calculate the leaching efficiency. The spent LiCoO2 samples after calcination and the residues after leaching are characterized by X-ray diffraction and scanning electron microscopy. The results show that nearly 100% of cobalt and more than 96% of lithium are leached under optimal conditions: succinic acid concentration of 1.5 mol L-1, H2O2 content of 4 vol.%, solid-to-liquid ratio of 15 g L-1, temperature of 70 °C, and reaction time of 40 min. Results are also given for fitting of the experimental data to acid leaching kinetic models.

  1. Extraction of Palladium(II from Hydrochloric Acid Solutions by Solvent Extraction with Mixtures Containing Either Cyanex 301 or LIX 63

    Directory of Open Access Journals (Sweden)

    Hoai Thanh Truong

    2017-12-01

    Full Text Available Cyanex 301 and 5,8-diethyl-7-hydroxyldodecane-6-oxime (LIX 63 can selectively extract Pd(II over Pt(IV from concentrated hydrochloric acid solutions. Therefore, solvent extraction experiments have been performed by extractant mixtures containing either Cyanex 301 or LIX 63, and the extraction behavior of Pd(II was compared. Among the mixtures of Cyanex 301, the highest synergistic enhancement coefficient was achieved by mixing Cyanex 301 and trioctylphosphine oxide (TOPO. However, it was very difficult to strip the Pd(II from the loaded mixture phase. Among the mixtures of LIX 63, the mixture of LIX 63 and alamine 336/TOPO enhanced the extraction of Pd(II. Although the synergistic coefficient by Cyanex 301 + TOPO was higher than that by LIX 63 + Alamine 336, the Pd(II in the loaded mixture phase of LIX 63 and alamine 336 was easily stripped by thiourea.

  2. Study on the inhibition of mild steel corrosion by 1,3-bis-(morpholin-4-yl-phenyl-methyl-thiourea in hydrochloric acid medium

    Directory of Open Access Journals (Sweden)

    Devaraj Karthik

    2014-12-01

    Full Text Available 1,3-Bis-(morpholin-4-yl-phenyl-methyl-thiourea (MBT was synthesized and their influence on the inhibition of corrosion on mild steel in various hydrochloric acid concentrations has been investigated by weight loss, potentiodynamic polarization, electrochemical impedance (EI, Tafel polarization, scanning electron microscope (SEM and FT-IR methods. The result of weight loss study shows that the corrosion inhibition efficiency (IE is directly proportional to the concentration of the inhibitor and inversely proportional to the temperature. Electrochemical study proved that the inhibitor acts as a mixed type inhibitor. SEM shows the formation of a protective film of the inhibitor on the mild steel. The IR data also provide evidence for the anticorrosion effect of the inhibitor.

  3. Electrochemical measurements for the corrosion inhibition of mild steel in 1 M hydrochloric acid by using an aromatic hydrazide derivative

    Directory of Open Access Journals (Sweden)

    P. Preethi Kumari

    2017-07-01

    Full Text Available The influence of an aromatic hydrazide derivative, 2-(3,4,5-trimethoxybenzylidene hydrazinecarbothioamide (TMBHC as corrosion inhibitor on mild steel in 1 M hydrochloric acid was studied by Tafel polarization and electrochemical impedance spectroscopy (EIS technique. The results showed that the inhibition efficiency (% IE of TMBHC increased with increasing inhibitor concentrations and also with increase in temperatures. TMBHC acted as a mixed type of inhibitor and its adsorption on mild steel surface was found to follow Langmuir’s adsorption isotherm. The evaluation of thermodynamic and activation parameters indicated that the adsorption of TMBHC takes place through chemisorption. The formation of protective film was further confirmed by scanning electron microscopy (SEM.

  4. Soil stabilisation using AMD sludge, compost and lignite: TCLP leachability and continuous acid leaching.

    Science.gov (United States)

    Tsang, Daniel C W; Olds, William E; Weber, Paul A; Yip, Alex C K

    2013-11-01

    Utilising locally available industrial by-products for in situ metal stabilisation presents a low-cost remediation approach for contaminated soil. This study explored the potential use of inorganic (acid mine drainage (AMD) sludge and zero-valent iron) and carbonaceous materials (green waste compost, manure compost, and lignite) for minimising the environmental risks of As and Cu at a timber treatment site. After 9-month soil incubation, significant sequestration of As and Cu in soil solution was accomplished by AMD sludge, on which adsorption and co-precipitation could take place. The efficacy of AMD sludge was comparable to that of zero-valent iron. There was marginal benefit of adding carbonaceous materials. However, in a moderately aggressive environment (Toxicity Characteristic Leaching Procedure), AMD sludge only suppressed the leachability of As but not Cu. Therefore, the provision of compost and lignite augmented the simultaneous reduction of Cu leachability, probably via surface complexation with oxygen-containing functional groups. Under continuous acid leaching in column experiments, combined application of AMD sludge with compost proved more effective than AMD sludge with lignite. This was possibly attributed to the larger amount of dissolved organic matter with aromatic moieties from lignite, which may enhance Cu and As mobility. Nevertheless, care should be taken to mitigate ecological impact associated with short-term substantial Ca release and continuous release of Al at a moderate level under acid leaching. This study also articulated the engineering implications and provided recommendations for field deployment, material processing, and assessment framework to ensure an environmentally sound application of reactive materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: 27Al NMR and pH-stat studies.

    Science.gov (United States)

    Wilson, G E; Falzone, C J; Johnson, R; Lee, H K

    1985-10-01

    Neutralization of mixtures of aluminum hydroxide-magnesium hydroxide gels and of magaldrate by hydrochloric acid were studied by 27Al NMR under conditions of both equilibrium and kinetic control. Under conditions where equilibrium has been attained, an aluminum NMR signal is detectable for suspensions of the mixed gels and magaldrate only after enough acid has been added to exhaust the acid-neutralizing capacity of the magnesium hydroxide. Mixed gels seem to form several soluble aluminum-containing species as neutralization proceeds. Under the conditions of the modified Beekman neutralization procedure, in which the species concentrations reflect neutralization kinetics, mixed gels show a sharp burst of the hexaaquoaluminum cation as acid is added followed by a slow loss of that cation from solution and an accompanying slow rise in pH. Magaldrate shows a steady increase in the hexaaquoaluminum cation with added acid. Differences between magaldrate and mixed gels are also apparent in pH-stat titrations in which magaldrate displays a biphasic response, contrasting to the two burst phases with an intervening lag phase observed for mixed gels. The results of the 27Al NMR and pH-stat titrations are consistent with the hypotheses that magaldrate is a homogeneous substance with a hydrotalcite-like structure and that mixed gels consist of a magnesium hydroxide core surrounded by aluminum hydroxide.

  6. Characterization of the Unusual Product from the Reaction between Cobalt(II) Chloride, Ethane-1,2-diamine, and Hydrochloric Acid: An Undergraduate Project Involving an Unknown Metal Complex.

    Science.gov (United States)

    Curtis, Neil F.; And Others

    1986-01-01

    Discusses the need for student research-type chemistry projects based upon "unknown" metal complexes. Describes an experiment involving the product from the reaction between cobalt(II) chloride, ethane-1,2-diamine (en) and concentrated hydrochloric acid. Outlines the preparation of the cobalt complex, along with procedure, results and…

  7. Sulfuric Acid and Ammonium Sulfate Leaching of Alumina from Lampang Clay

    Directory of Open Access Journals (Sweden)

    Paweena Numluk

    2012-01-01

    Full Text Available The rapid development of the global alumina industry has led to a considerable increase in the production alumina and processing of alumina from non-bauxitic sources. Lampang clays comprise various minerals that contain about 22.70 wt% of extractable alumina. Local clay was ground, activated by calcination and treated with sulfuric acid to extract alumina. In the activation step, the effects of temperature and time on the extraction of alumina and iron were investigated. The leaching experiments were performed on clay samples with particle sizes less than 200 mesh. The samples were calcined at different temperatures, ranging from 450°C to 1050°C, and for different periods, ranging from 30 to 150 min. The optimum conditions for the extraction of alumina from Lampang clay include grinding the clay to pass through a 200 mesh sieve, calcining the ground clay at 750°C for 30 min, extracting the alumina from the calcined clay by leaching with 3M sulfuric acid, and using an acid to clay ratio of 80 wt% at 100°C for 120 min. An aluminum dissolution efficiency of 95.1 % was achieved under the conditions that resulted in the maximum dissolution efficiency of iron (26.6 %.

  8. Antimony leaching in plastics from waste electrical and electronic equipment (WEEE) with various acids and gamma irradiation.

    Science.gov (United States)

    Tostar, Sandra; Stenvall, Erik; Boldizar, Antal; Foreman, Mark R St J

    2013-06-01

    There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5M) dissolved in either dimethyl sulfoxide or water (at ca. 23°C and heated to ca. 105°C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Effects of ozone and acid mist on foliar leaching from eastern white pine and sugar maple

    Energy Technology Data Exchange (ETDEWEB)

    Lovett, G.M.; Hubbell, J.G. (New York Botanical Garden, Millbrook, NY (USA))

    1991-01-01

    Upper canopy branches of mature eastern white pine and sugar maple were exposed in the field to ozone for 5 h, followed by acid mist for 1 h, and the exchange of major ions between the mist and the foliage was measured. The two species responded similarly to the pollutants: ozone exposure did not affect canopy exchange of any ions, but the pH 3.8 mist approximately doubled the leaching of Ca{sup 2+} and Mg{sup 2+} relative to the pH 5.0 mist. Hydrogen ions were released from the branches of both species in the pH 5.0 treatment but taken up from solution in the pH 3.8 treatment. Consideration of ionic balance in the chemical exchange indicates that organic acids were released from the branches of both species. In the white pine, it appears that these acids were deprotonated in the pH 5.0 solution, but not in the pH 3.8 solution. In the sugar maple, some acid deprotonation appears to have occurred under both pH treatments. In a related experiment, sugar maple branches that were moderately damaged by pear thrips did not have canopy exchange rates different from undamaged branches. Canopy exchange in the damaged branches did not respond to ozone treatment. Hydrogen ions were retained at pH 3.8 and released at pH 5.0, as in the undamaged branches. In the damaged branches, leaching of Ca(II) and Mg(II) tended to be higher at pH 3.8, although the results were not statistically significant. Overall, it is concluded that short-term ozone exposures that do not produce visible damage do not affect foliar leaching, but that the acidity of rain can have a significant effect on Ca(II), Mg(II) and H+ exchange in white pine and sugar maple canopies. The net effect of those canopies on the acidity of the rain passing through them will depend on the initial acidity of the rain. 29 refs., 5 figs., 2 tabs.

  10. Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.

    Science.gov (United States)

    Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Liu, Zhao-Peng; Jin, Fei

    2014-04-30

    Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Ion exchange investigation for recovery of uranium from acidic pregnant leach solutions

    Directory of Open Access Journals (Sweden)

    Danko Bożena

    2017-09-01

    Full Text Available The article describes studies on the separation of uranium from acid pregnant leach solutions obtained from Polish uranium ores: dictyonema shales and sandstone rocks. Ion exchange chromatography was applied for uranium sorption, using commercially available, strongly basic anion exchanger, Dowex 1. In model experiments, the influence of degree of crosslinking of Dowex 1 on the efficiency of uranium extraction was investigated. The effect of H2SO4 concentration on the breakthrough curve of uranyl ions for the Dowex 1 resins, of different crosslinking: X4, X8 and X10, was examined. Unexpectedly high increase of exchange capacity of uranium was observed in case of Dowex 1X10. This gives potential opportunity of improving the effectiveness of uranium recovery process. Applying column packed with Dowex 1X10, ‘yellow cake’ with ca. 92% yield and high purity of recovered uranium was obtained. A block diagram of the procedure for uranium and lanthanides extraction from acidic leach liquor has been proposed.

  12. Using pyrolytic acid leaching as a pretreatment step in a biomass fast pyrolysis plant: Process design and economic evaluation

    OpenAIRE

    Oudenhoven, S.R.G.; van der Ham, A.G.J.; H. Van den Berg; Westerhof, R.J.M.; Kersten, S.R.A.

    2016-01-01

    Removing alkali and alkaline earth metals (AAEMs) from biomass, with pyrolytic acids, before pyrolysis leads to increased organic oil and sugar yields. These pyrolytic acids are produced and concentrated within the pyrolysis process itself. The purpose of this paper was to evaluate under which conditions acid leaching of pinewood, bagasse and straw can improve the technical and economic feasibility of a pyrolysis process. Therefore, a preliminary process design for the implementation of acid ...

  13. Leaching behavior of heavy metals and transformation of their speciation in polluted soil receiving simulated acid rain.

    Science.gov (United States)

    Zheng, Shun-an; Zheng, Xiangqun; Chen, Chun

    2012-01-01

    Heavy metals that leach from contaminated soils under acid rain are of increasing concern. In this study, simulated acid rain (SAR) was pumped through columns of artificially contaminated purple soil. Column leaching tests and sequential extraction were conducted for the heavy metals Cu, Pb, Cd, and Zn to determine the extent of their leaching as well as to examine the transformation of their speciation in the artificially contaminated soil columns. Results showed that the maximum leachate concentrations of Cu, Pb, Cd, and Zn were less than those specified in the Chinese Quality Standards for Groundwater (Grade IV), thereby suggesting that the heavy metals that leached from the polluted purple soil receiving acid rain may not pose as risks to water quality. Most of the Pb and Cd leachate concentrations were below their detection limits. By contrast, higher Cu and Zn leachate concentrations were found because they were released by the soil in larger amounts as compared with those of Pb and Cd. The differences in the Cu and Zn leachate concentrations between the controls (SAR at pH 5.6) and the treatments (SAR at pH 3.0 and 4.5) were significant. Similar trends were observed in the total leached amounts of Cu and Zn. The proportions of Cu, Pb, Cd, and Zn in the EXC and OX fractions were generally increased after the leaching experiment at three pH levels, whereas those of the RES, OM, and CAR fractions were slightly decreased. Acid rain favors the leaching of heavy metals from the contaminated purple soil and makes the heavy metal fractions become more labile. Moreover, a pH decrease from 5.6 to 3.0 significantly enhanced such effects.

  14. Effects of dietary hydrochloric acid on voluntary food intake and metabolism of sheep in relation to the use of mineral acids as silage additives.

    Science.gov (United States)

    L'Estrange, J L; McNamara, T

    1975-09-01

    1. In Expt I, a pelleted grass-meal diet was supplemented with hydrochloric acid, added to the grass pellets before feeding, at five levels from 0 to 628 mmol/kg dry matter (DM). Each diet was offered ad lib. for 21 d to five sheep in a 5 x 5 Latin-square design. 2. Voluntary food intake decreased rectilinearly with increasing HCl supplementation (P less than 0.001), to 42% of the control value for sheep on the high-HCl diet. The decrease in food intake was related both to dietary pH and to the extent of metabolic acidosis induced by the HCl treatment. Although the pH of rumen fluid decreased slightly with increasing HCl supplementation, effects of the HCl treatment on volatile fatty acid concentrations in rumen fluid were not significant (P greater than 0.05). 3. In Expt 2, palatability and metabolic effects of dietary HCl were studied by comparing its effect when mixed into the pelleted grass meal before feeding, with and without a supplement of an equivalent amount of sodium bicarbonate given intraruminally, or when HCl was given intraruminally while the sheep consumed pelleted grass meal alone. Each of the three treatments was given at two levels of HCl, 280 and 560 mmol/kg DM. At each level of dietary HCl supplementation, the three treatments and the control diet (pelleted grass meal alone) were each given to four sheep, in a Latin-square design, for 11 d. 4. At the low level of supplementation, HCl, when mixed into the pelleted grass meal, reduced food intake by 17%, this effect was not altered by NaHCO3 supplementation, but when HCl was given intraruminally food intake was not reduced. At the high level of HCl supplementation, food intake was reduced by about 40% by each method of HCl supplementation; and NaHCO3 supplementation did not appreciably alter the effect of HCl on food intake, but prevented metabolic acidosis associated with the HCl treatments. Food intakes for the low-HCl treatments were significantly higher than those for the high-HCl treatments

  15. Hydrometallurgical process for zinc recovery from electric arc furnace dust (EAFD): part I: Characterization and leaching by diluted sulphuric acid.

    Science.gov (United States)

    Oustadakis, P; Tsakiridis, P E; Katsiapi, A; Agatzini-Leonardou, S

    2010-07-15

    The present paper is the first of a series of two articles dealing with the development of an integrated process for the recovery of zinc from electric arc furnace dust (EAFD), a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Part I presents the EAFD characterization and its leaching process by diluted sulphuric acid, whereas Part II deals with the purification of the leach liquor and the recovery of zinc by solvent extraction/electrowinning. The characterization of the examined electric arc furnace dust was carried out by using granulometry analysis, chemical analysis, X-ray diffraction (XRD), thermogravimetric/differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The leaching process was based on the Zn extraction with diluted sulphuric acid from EAFD under atmospheric conditions and without using any preliminary treatment. Statistical design and analysis of experiments were used, in order to determine the main effects and interactions of the leaching process factors, which were: acid normality, temperature and solid to liquid ratio. The zinc recovery efficiency on the basis of EAFD weight reached 80%. X-ray diffraction and scanning electron microscopy were used for the characterization of the leached residues. 2010 Elsevier B.V. All rights reserved.

  16. Minimizing the creation of spent pickling liquors in a pickling process with high-concentration hydrochloric acid solutions: mechanism and evaluation method.

    Science.gov (United States)

    Tang, Bing; Su, Wen; Wang, Jing; Fu, Fenglian; Yu, Guojun; Zhang, Jianyin

    2012-05-15

    The purpose of this investigation is to propose a strategy for minimizing the creation of spent pickling liquors through the synergistic corrosion inhibition of OP-10 and potassium iodide, thus facilitating a cleaner production process for acid pickling of metals with a high-concentration solution (6.0 mol/l) of hydrochloric acid. Results obtained with the methods of weight loss and electrochemical polarization showed that adding KI and OP-10 could enhance the energy barrier of the corrosion reaction and improved the corrosion inhibition for mild steel in high concentration of HCl solutions. A synergistic effect was identified when KI and OP-10 were present in suitable proportions. The results of the electrochemical experiments and scanning electron microscope (SEM) observations showed that the complex inhibitor was a mixed-type inhibitor and it formed a compact film on the metal surface, thus providing an effective protection for the metal in the aggressive solutions, which significantly minimized the creation of spent pickling liquors. A simple and convenient method was also proposed for the quantificational evaluation of the inhibition degree in the creation of spent pickling liquors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Electrochemical Study on Corrosion Inhibition of Copper in Hydrochloric Acid Medium and the Rotating Ring-Disc Voltammetry for Studying the Dissolution

    Directory of Open Access Journals (Sweden)

    A. K. Satpati

    2011-01-01

    Full Text Available Dissolution characteristics of copper in hydrochloric acid medium and the effect of 4-amino 1,2,4-triazole (ATA on the corrosion process have been studied using conventional electrochemical techniques and rotating ring-disc electrodes (RRDEs. Corrosion potential (corr and corrosion current density (corr were obtained by Tafel extrapolation methods. Charge transfer resistance (ct and double-layer capacitance (dl were obtained from the electrochemical impedance spectroscopy (EIS. ATA was shown to be an effective inhibitor for the copper-corrosion inhibition in acid medium. The corrosion rate was retarded in presence of inhibitors mainly because of the adsorption of the inhibitor on the electrode surface. Adsorption of the inhibitor on the metal surface was found to follow the Langmuir adsorption isotherm. Standard free energy change of the adsorption process (Δ0ad was calculated to be −54.3 kJ mol−1; such a large negative value of Δ0ad suggests the prescence of a chemisorption process.

  18. Uranium Leaching from Contaminated Soil Utilizing Rhamnolipid, EDTA, and Citric Acid

    Directory of Open Access Journals (Sweden)

    Sara Asselin

    2014-01-01

    Full Text Available Biosurfactants have recently gained attention as “green” agents that can be used to enhance the remediation of heavy metals and some organic matter in contaminated soils. The overall objective of this paper was to investigate rhamnolipid, a microbial produced biosurfactant, and its ability to leach uranium present in contaminated soil from an abandoned mine site. Soil samples were collected from two locations in northern Arizona: Cameron (site of open pit mining and Leupp (control—no mining. The approach taken was to first determine the total uranium content in each soil using a hydrofluoric acid digestion, then comparing the amount of metal removed by rhamnolipid to other chelating agents EDTA and citric acid, and finally determining the amount of soluble metal in the soil matrix using a sequential extraction. Results suggested a complex system for metal removal from soil utilizing rhamnolipid. It was determined that rhamnolipid at a concentration of 150 μM was as effective as EDTA but not as effective as citric acid for the removal of soluble uranium. However, the rhamnolipid was only slightly better at removing uranium from the mining soil compared to a purified water control. Overall, this study demonstrated that rhamnolipid ability to remove uranium from contaminated soil is comparable to EDTA and to a lesser extent citric acid, but, for the soils investigated, it is not significantly better than a simple water wash.

  19. Hydrometallurgical recovery of metal values from sulfuric acid leaching liquor of spent lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiangping; Chen, Yongbin; Zhou, Tao, E-mail: zhoutao@csu.edu.cn; Liu, Depei; Hu, Hang; Fan, Shaoyun

    2015-04-15

    Highlights: • Selective precipitation and solvent extraction were adopted. • Nickel, cobalt and lithium were selectively precipitated. • Co-D2EHPA was employed as high-efficiency extraction reagent for manganese. • High recovery percentages could be achieved for all metal values. - Abstract: Environmentally hazardous substances contained in spent Li-ion batteries, such as heavy metals and nocuous organics, will pose a threat to the environment and human health. On the other hand, the sustainable recycling of spent lithium-ion batteries may bring about environmental and economic benefits. In this study, a hydrometallurgical process was adopted for the comprehensive recovery of nickel, manganese, cobalt and lithium from sulfuric acid leaching liquor from waste cathode materials of spent lithium-ion batteries. First, nickel ions were selectively precipitated and recovered using dimethylglyoxime reagent. Recycled dimethylglyoxime could be re-used as precipitant for nickel and revealed similar precipitation performance compared with fresh dimethylglyoxime. Then the separation of manganese and cobalt was conducted by solvent extraction method using cobalt loaded D2EHPA. And McCabe–Thiele isotherm was employed for the prediction of the degree of separation and the number of extraction stages needed at specific experimental conditions. Finally, cobalt and lithium were sequentially precipitated and recovered as CoC{sub 2}O{sub 4}⋅2H{sub 2}O and Li{sub 2}CO{sub 3} using ammonium oxalate solution and saturated sodium carbonate solution, respectively. Recovery efficiencies could be attained as follows: 98.7% for Ni; 97.1% for Mn, 98.2% for Co and 81.0% for Li under optimized experimental conditions. This hydrometallurgical process may promise a candidate for the effective separation and recovery of metal values from the sulfuric acid leaching liquor.

  20. Investigation of Enhanced Leaching of Lithium from α-Spodumene Using Hydrofluoric and Sulfuric Acid

    Directory of Open Access Journals (Sweden)

    Hui Guo

    2017-10-01

    Full Text Available An effective method using hydrofluoric and sulfuric acid was proposed to enhance the leaching of lithium from α-spodumene, without calcination that is subjected to 1000 °C for phase transformation. The thermodynamic feasibility of the reactions was firstly verified. Dissolution conditions were tested to maximize the leaching efficiency of lithium and with efficient utilization of hydrofluoric acid (HF served as evaluation criteria. The results showed that 96% of lithium could be transferred into lixivium with an ore/HF/H2SO4 ratio of 1:3:2 (g/mL/mL, at 100 °C for 3 h. Due to the fact that HF molecules were the main reaction form, the dissolution behaviors were theoretically represented and investigated by dissolution in HF/H2SO4. When combined with chemical elements analyses and characterizations, the results of the dissolution behaviors revealed that α-spodumene and albite were preferentially dissolved over quartz. Insoluble fluoroaluminates, such as AlF3, cryolite (Na3AlF6 and cryolithionite (Na3Li3Al2F12, were generated and might be further partially dissolved by H2SO4. Fluorosilicates, such as K2SiF6, Na2SiF6, or KNaSiF6, were also generated as a part of the insoluble residues. This work provides fundamental insight into the role of HF/H2SO4 played in the dissolution of α-spodumene, and sheds light on a novel and promising process to efficiently extract lithium.

  1. Synergism between protocatechualdehyde and rare earth cerium(IV) ion on the corrosion of cold rolled steel in hydrochloric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.H.; Fu, H. [Department of Fundamental Courses, Southwest Forestry University, Kunming (China); Deng, S.D. [Department of Wood Science and Technology, Southwest Forestry University, Kunming (China); Mu, G.N. [Department of Chemistry, Yunnan University, Kunming (China)

    2010-03-15

    The synergism between protocatechualdehyde (PAL, 3,4-dihydroxy-benzaldehye) and rare earth cerium(IV) ion (Ce{sup 4+}) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) solution has been investigated by weight loss and potentiodynamic polarization methods. The results reveal that PAL has a moderate inhibitive effect, while Ce{sup 4+} has a poor effect. Incorporation of PAL with Ce{sup 4+} improves the inhibition performance significantly, and exhibits synergistic inhibition effect. The adsorption of individual PAL obeys the Temkin adsorption isotherm, and the adsorption of the complex of PAL and Ce{sup 4+} accords with the Temkin adsorption isotherm too. The thermodynamic parameters of adsorption heat ({delta}H{sup 0}), adsorption free energy ({delta}G{sup 0}), and adsorption entropy ({delta}S{sup 0}) are calculated and discussed. Polarization curves show that individual PAL acts as a mixed-type inhibitor, while Ce{sup 4+} slightly inhibits the corrosion reaction. The complex of PAL and Ce{sup 4+} acts as a mixed-type inhibitor, which drastically inhibits both anodic and cathodic reactions. Depending on the results, the synergism mechanism is proposed from the viewpoint of adsorption theory. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. Improve the Properties of p-i-n α-Si:H Thin-Film Solar Cells Using the Diluted Hydrochloric Acid-Etched GZO Thin Films

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2013-01-01

    Full Text Available Gallium-doped zinc oxide (GZO thin films were deposited on glass, and the process parameters are RF power of 50 W and working pressure of 5 mTorr, and the substrate temperature was changed from room temperature to 300°C. At first, the thickness was around 300 nm by controlling the deposition time. The effects of substrate temperature on the crystallinity, lattice constant (c, carrier mobility, carrier concentration, resistivity, and optical transmission rate of the GZO thin films were studied. The 200°C-deposited GZO thin films had the best crystallinity, the larger carrier concentration and carrier mobility, and the lowest resistivity. For that, the thickness of the GZO thin films was extended to around 1000 nm. Hydrochloric (HCl acid solutions with different concentrations (0.1%, 0.2%, and 0.5% were used to etch the surfaces of the GZO thin films, which were then used as the substrate electrodes to fabricate the p-i-n α-Si:H thin-film solar cells. The haze ratio of the GZO thin films increased with increasing HCl concentration, and that would effectively enhance light trapping inside the absorber material of solar cells and then improve the efficiency of the fabricated thin-film solar cells.

  3. Role of temperature and hydrochloric acid on the formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons during combustion of paraffin powder, polymers, and newspaper.

    Science.gov (United States)

    Takasuga, Takumi; Umetsu, Norihito; Makino, Tetsuya; Tsubota, Katsuya; Sajwan, Kenneth S; Kumar, Kurunthachalam Senthil

    2007-07-01

    Formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were determined using a laboratory-scale incinerator when combusting materials at different temperatures, different concentrations of hydrochloric acid (HCl), and when combusting various types of polymers/newspaper. Polychlorobenzenes (PCBz), polychlorophenols (PCPhs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and their toxic equivalency (TEQ) and PAHs were highlighted and reported. Our results imply maximum formation of chlorinated hydrocarbons at 400 degrees C in the following order; PCBz>or=PCPhs>PCDFs>PCDDs>TEQ on a parts-per-billion level. Similarly, a maximum concentration of chlorinated hydrocarbons was noticed with an HCl concentration at 1000 ppm with the presence of paraffin powder in the following order; PAHs>PCBz>or=PCPhs>PCDFs>PCDDs>TEQ an a parts-per-billion level. PAHs were not measured at different temperatures. Elevated PAHs were noticed with different HCl concentrations and paraffin powder combustion (range: 27-32 microg/g). While, different polymers and newspaper combusted, nylon and acrylonitrile butadiene styrene (ABS) produced the maximum hydrogen cyanide (HCN) concentration, concentrations of PCDD/FS, dioxin-like polychlorinated biphenyls (DL-PCBs), and TEQ were in a decreasing order: polyvinylchloride (PVC)ABS = blank. Precursors of PCBs were in a decreasing order: PPABSABSABSABS< PET

  4. Decontamination of CCA-treated eucalyptus wood waste by acid leaching.

    Science.gov (United States)

    Ferrarini, Suzana Frighetto; Dos Santos, Heldiane Souza; Miranda, Luciana Gampert; Azevedo, Carla Maria Nunes; Maia, Sandra Maria; Pires, Marçal

    2016-03-01

    Preservatives such as chromated copper arsenate (CCA) are used to increase the resistance of wood to deterioration. The components of CCA are highly toxic, resulting in growing concern over the disposal of the waste generated. The aim of this study was to investigate the removal of Cu, Cr and As present in CCA-treated eucalyptus wood from utility poles removed from service in southern Brazil, in order to render them non-hazardous waste. The removal was carried out by acid leaching in bench-scale and applying optimal extractor concentration, total solid content, reactor volume, temperature and reaction time obtained by factorial experiments. The best working conditions were achieved using three extraction steps with 0.1 mol L(-1) H2SO4 at 75°C for 2h each (total solid content of 15%), and 3 additional 1h-long washing steps using water at ambient temperature. Under these conditions, removal of 97%, 85% and 98% were obtained for Cu, Cr and As, respectively, rendering the decontaminated wood non-hazardous waste. The wastewater produced by extraction showed acid pH, high organic loading as well as high concentrations of the elements, needing prior treatment to be discarded. However, rinsing water can be recycled in the extraction process without compromising its efficiency. The acid extraction is a promising alternative for CCA removal from eucalyptus wood waste in industrial scale. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Acid leaching of oxide-sulphide copper ore prior the flotation: A way for an increased metal recovery

    Directory of Open Access Journals (Sweden)

    Sokić Miroslav D.

    2015-01-01

    Full Text Available Copper mine "Cerovo"- East Serbia as well as the other ore bodies in its vicinity contain a significant amount of oxide copper minerals in their uper layers (>40%. Processing of such mixed ores by the existing concentration technologies leads to a substantial copper losses (<60%. Reduction of "oxide copper", by acid leaching prior the flotation concentration, can increase the overall copper efficiency up to more than 70% in the single-stage leaching, achieving an efficiency in the flotation concentration stage higher than 75%. Based on the performed experimental results the flow sheet for processing of the mixed oxide-sulphide copper ore is proposed.

  6. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis

    Directory of Open Access Journals (Sweden)

    Toni Gutknecht

    2015-01-01

    Full Text Available Metal oxide varistors (MOVs are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production.

  7. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis.

    Science.gov (United States)

    Gutknecht, Toni; Gustafsson, Anna; Forsgren, Christer; Ekberg, Christian; Steenari, Britt-Marie

    2015-01-01

    Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production.

  8. A comparative study of solid carbon acid catalysts for the esterification of free fatty acids for biodiesel production. Evidence for the leaching of colloidal carbon.

    Science.gov (United States)

    Deshmane, Chinmay A; Wright, Marcus W; Lachgar, Abdessadek; Rohlfing, Matthew; Liu, Zhening; Le, James; Hanson, Brian E

    2013-11-01

    The preparation of a variety of sulfonated carbons and their use in the esterification of oleic acid is reported. All sulfonated materials show some loss in activity associated with the leaching of active sites. Exhaustive leaching shows that a finite amount of activity is lost from the carbons in the form of colloids. Fully leached catalysts show no loss in activity upon recycling. The best catalysts; 1, 3, and 6; show initial TOFs of 0.07 s(-1), 0.05 s(-1), and 0.14 s(-1), respectively. These compare favorably with literature values. Significantly, the leachate solutions obtained from catalysts 1, 3, and 6, also show excellent esterification activity. The results of TEM and catalyst poisoning experiments on the leachate solutions associate the catalytic activity of these solutions with carbon colloids. This mechanism for leaching active sites from sulfonated carbons is previously unrecognized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Chemical Polymerization Kinetics of Poly-O-Phenylenediamine and Characterization of the Obtained Polymer in Aqueous Hydrochloric Acid Solution Using K2Cr2O7 as Oxidizing Agent

    Directory of Open Access Journals (Sweden)

    S. M. Sayyah

    2014-01-01

    Full Text Available The oxidative chemical polymerization of o-phenylenediamine (OPDA was studied in hydrochloric acid solution using potassium dichromate as oxidant at 5°C. The effects of potassium dichromate, hydrochloric acid, and monomer concentrations on the polymerization reaction were investigated. The order of reaction with respect to potassium dichromate, hydrochloric acid, and monomer concentration was found to be 1.011, 0.954, and 1.045, respectively. Also, the effect of temperature on the polymerization rate was studied and the apparent activation energy of the polymerization reaction was found to be 63.658 kJ/mol. The obtained polymer was characterized using XPS, IR, UV-visible, and elemental analysis. The surface morphology of the obtained polymers was characterized by X-ray diffraction and transmission electron microscopy (TEM. The TGA analysis was used to confirm the proposed structure and number of water molecules in each polymeric chain unit. The ac conductivity (σac of (POPDA was investigated as a function of frequency and temperature. The ac conductivity was interpreted as a power law of frequency. The frequency exponent (s was found to be less than unity and decreased with the increase of temperature, which confirms that the correlated barrier hopping model was the dominant charge transport mechanism.

  10. Treasure of the Past VI: Standard Potential of the Silver-Silver-Chloride Electrode from 0° to 95° C and the Thermodynamic Properties of Dilute Hydrochloric Acid Solutions

    Science.gov (United States)

    Bates, Roger G.; Bower, Vincent E.

    2001-01-01

    From electromotive-force measurements of the cell without liquid junction: Pt;H2,HCl(m),AgCl;Agthrough the range 0° to 95° C, calculations have been made of (1) the standard potential of the silver–silver-chloride electrode, (2) the activity coefficient of hydrochloric acid in aqueous solutions from m (molality) =0 to m=0.1 and from 0° to 90° C, (3) the relative partial molal heat content of hydrochloric acid, and (4) the relative partial molal heat capacity of hydrochloric acid. The extrapolations were made by the method of least squares with the aid of punch-card techniques. Data from at least 24 cells were analyzed at each temperature, and 81 cells were studied at 25° C. The value of the standard potential was found to be 0.22234 absolute volt at 25° C, and the standard deviation was 0.02 millivolt at 0° C, 0.01 millivolt at 25° C, and 0.09 millivolt at 95° C. The results from 0° to 60° C are compared with earlier determinations of the standard potential and other quantities derived from the electromotive force. PMID:27500034

  11. In vitro lead bioaccessibility and phosphate leaching as affected by surface application of phosphoric acid in lead-contaminated soil.

    Science.gov (United States)

    Yang, J; Mosby, D E; Casteel, S W; Blanchar, R W

    2002-11-01

    Phosphate treatment of lead-contaminated soil may be a cost-effective remedial alternative for in situ stabilizing soil Pb and reducing Pb toxicology to human. The leaching behaviors of the P added to soil surface and the effect on subsurface Pb bioaccessibility must be addressed for this remedial technology to be acceptable. A smelter-contaminated soil containing an average of 2,670 mg Pb kg(-1), collected from the Jasper County Superfund Site located in Jasper County, Missouri, was surface treated with 10 g P kg(-1) as phosphoric acid (H(3)PO(4)). Following a simulated column leaching and 90-day treatment of field plots, respectively, bioaccessible Pb, P, and pH in soil profile were measured. Surface treatment using H(3)PO(4) effectively stabilized soil Pb and reduced leachable Pb and the bioaccessibility. Phosphate leached into deeper profile significantly lowered bioaccessible Pb in subsurface. Reduction of Pb bioaccessibility increased as a linear function of increasing soil P. Although surface H(3)PO(4) treatment resulted in an enhanced leaching of added P and may increase potential risk of surface and groundwater pollution, the P leaching under field conditions is very limited. Lime addition following the treatment may reduce the leachability of added P and further immobilize soil Pb.

  12. The influence of mechanical activation of chalcopyrite on the selective leaching of copper by sulphuric acid

    Directory of Open Access Journals (Sweden)

    Achimovičová, M.

    2006-01-01

    Full Text Available In this paper chalcopyrite, CuFeS2, has been selective leached by H2SO4 as leaching agent (170 g/dm3 in procedure of hydrometallurgical production of copper. Mechanical activation of the chalcopyrite resulted in mechanochemical surface oxidation as well as in the mineral surface and bulk disordering. Furthermore, the formation of agglomerates during grinding was also occured. Surface changes of the samples using infrared spectroscopy and scanning electron microscopy methods were investigated before and after leaching. The leaching rate, specific surface area, structural disorder as well as copper extraction increased with the mechanical activation of mineral.

  13. Sustainable Soil Washing: Shredded Card Filtration of Potentially Toxic Elements after Leaching from Soil Using Organic Acid Solutions.

    Directory of Open Access Journals (Sweden)

    Christopher Ash

    Full Text Available Shredded card (SC was assessed for use as a sorbent of potentially toxic elements (PTE carried from contaminated soil in various leachates (oxalic acid, formic acid, CaCl2, water. We further assessed SC for retention of PTE, using acidified water (pH 3.4. Vertical columns and a peristaltic pump were used to leach PTE from soils (O and A/B horizons before passing through SC. Sorption onto SC was studied by comparing leachates, and by monitoring total PTE contents on SC before and after leaching. SC buffers against acidic soil conditions that promote metals solubility; considerable increases in solution pH (+4.49 were observed. Greatest differences in solution PTE content after leaching with/without SC occurred for Pb. In oxalic acid, As, Cd, Pb showed a high level of sorption (25, 15, and 58x more of the respective PTE in leachates without SC. In formic acid, Pb sorption was highly efficient (219x more Pb in leachate without SC. In water, only Pb showed high sorption (191x more Pb in leachate without SC. In desorption experiments, release of PTE from SC varied according to the source of PTE (organic/mineral soil, and type of solvent used. Arsenic was the PTE most readily leached in desorption experiments. Low As sorption from water was followed by fast release (70% As released from SC. A high rate of Cd sorption from organic acid solutions was followed by strong retention (~12% Cd desorption. SC also retained Pb after sorption from water, with subsequent losses of ≤8.5% of total bound Pb. The proposed use of this material is for the filtration of PTE from extract solution following soil washing. Low-molecular-mass organic acids offer a less destructive, biodegradable alternative to strong inorganic acids for soil washing.

  14. Ex Vivo Liver Experiment of Hydrochloric Acid-Infused and Saline-Infused Monopolar Radiofrequency Ablation: Better Outcomes in Temperature, Energy, and Coagulation.

    Science.gov (United States)

    Jiang, Xiong-ying; Gu, Yang-kui; Huang, Jin-hua; Gao, Fei; Zou, Ru-hai; Zhang, Tian-qi

    2016-04-01

    To compare temperature, energy, and coagulation between hydrochloric acid-infused radiofrequency ablation (HAIRFA) and normal saline-infused radiofrequency ablation (NSIRFA) in ex vivo porcine liver model. 30 fresh porcine livers were excised in 60 lesions, 30 with HAIRFA and the other 30 with NSIRFA. Both modalities used monopolar perfusion electrode connected to a RF generator set at 103 °C and 30 W. In each group, ablation time was set at 10, 20, or 30 min (10 lesions from each group at each time). We compared tissue temperatures (at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 cm away from the electrode tip), average power, deposited energy, deposited energy per coagulation volume (DEV), coagulation diameters, coagulative volume, and spherical ratio between the two groups. Temperature-time curves showed that HAIRFA provided progressively greater heating than that of NSIRFA. At 30 min, mean average power, deposited energy, coagulation volumes (113.67 vs. 12.28 cm(3)) and diameters, and increasing in tissue temperature were much greater with HAIRFA (P < 0.001 for all), except DEV was lower (456 vs. 1396 J/cm(3), P < 0.001). The spherical ratio was closer to 1 with HAIRFA (1.23 vs. 1.46). Coagulation diameters, volume, and average power of HAIRFA increased significantly with longer ablation times. While with NSIRFA, these characteristics were stable till later 20 min, except the power decreased with longer ablation times. HAIRFA creates much larger and more spherical lesions by increasing overall energy deposition, modulating thermal conductivity, and transferring heat during ablation.

  15. [Effect of Hydrochloric acid on invasion of Ascaris suum; enzyme activity in the digestive system and serum of newborn piglets].

    Science.gov (United States)

    Jabłonowski, Z; Romaniuk, K; Piechocki, D; Zółtowska, K; Lukaszewicz-Babecka, J; Dziekońska-Rynko, I J

    1995-01-01

    The studies were carried out on twenty newborn piglets. They were divided into four groups. The groups no 3 and no 4 were given intragastric 0.18% HCl from the 3th day of experiment. The groups no 2 and no 4 were infected on the 7th day with 10,000 invasive eggs of Ascaris suum. The presence of A. suum larvae in the lungs and liver was examined after one week lasting invasion by Baermann method. The total acidity in the gastric content was measured. The activity of alpha-amylase, lipase and proteases was determined in the extracts from pancreas and in the contents of stomach, duodenum and jejunum. The level of pepsinogens and alpha-amylase in the animals serum was studied. The intensity of Ascaris invasion was slightly higher in the group which was given HCl than in the infected group without HCl. The activity of digestive enzymes in the both groups was similar. Only in the stomach content from the 4th group the activity of pepsin was higher (p < 0.05), and alpha-amylase and lipase were lower (p < 0.01) than in the 2nd and in the 3th group. The level of pepsinogens was always lower and alpha-amylase higher in the serum of infected animals than in uninfected groups.

  16. Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid

    Directory of Open Access Journals (Sweden)

    Gustavo D. Rosales

    2016-09-01

    Full Text Available Parameters affecting the kinetics of the dissolution of β-spodumene with hydrofluoric acid have been investigated. The experimental tests were carried out in a closed vessel. The influence of several parameters, such as stirring speed, temperature, and reaction time were studied in order to deduce the kinetics of the dissolution reaction. The other parameters, particle size −45 μm; HF concentration 4% v/v, and the solid–liquid ratio 0.95% w/v were kept constant. The results indicate that the stirring speed does not have an important effect on the dissolution of the mineral above 330 rpm. The extent of the leaching of β-spodumene increases with temperature and reaction time augmentations. Scanning electron microscope (SEM analyses of some residues in which the conversion was lower than 30% indicated a selective attack on certain zones of the particle. The treatment of the experimental data was carried out using the Modelado software. The model that best represents the dissolution of the mineral is the following: ln(1 − X = −b1 [ln(1 + b2t − b2t/(1 + b2t]. This model is based on “nucleation and growth of nuclei” theory, and describes the style of attack physically observed by SEM on the residues.

  17. Extraction of indium-tin oxide from end-of-life LCD panels using ultrasound assisted acid leaching.

    Science.gov (United States)

    Souada, Malika; Louage, Christophe; Doisy, Jean-Yves; Meunier, Ludivine; Benderrag, Abdelkader; Ouddane, Baghdad; Bellayer, Séverine; Nuns, Nicolas; Traisnel, Michel; Maschke, Ulrich

    2018-01-01

    In this report, indium-tin-oxide (ITO)-layer extraction from end-of-life (EOL) Liquid Crystal Displays (LCDs) was discussed by sulfuric acid leaching with simultaneous application of ultrasonication on the ITO-side of glass/ITO panels, exhibiting various dimensions. Applying this technique presents several advantages compared to the traditional leaching process such as fast and controllable kinetics, high extraction yield of indium and tin, selective recovery of these two metals possible, and the opportunity to recycle the neat glass separately avoiding additional separation processes. ITO-dissolution kinetics from EOL LCD panels were investigated as function of leaching time and acidity of sulfuric acid. At a temperature of 60°C, a nearly quantitative indium yield was obtained using an acid concentration of 18mol/L by simultaneous application of ultrasonication, whereas only 70% were recovered in the absence of ultrasound. Results from ICP-AES agreed well with SEM/BSE observations demonstrating the high efficiency of the ultrasound assisted process since only 3-4min were required to obtain maximum ITO recovery. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. PbSO4 Leaching in Citric Acid/Sodium Citrate Solution and Subsequent Yielding Lead Citrate via Controlled Crystallization

    Directory of Open Access Journals (Sweden)

    Dongsheng He

    2017-06-01

    Full Text Available Lead citrate is a key precursor for the green recycling of spent lead acid battery paste in a citric acid/sodium citrate (CA/SC solution. In this study, the main paste component, PbSO4, was leached and crystallized to yield lead citrate. Results showed that the leaching of PbSO4 in citric acid/sodium citrate solution was remarkably enhanced by an increase in temperature from 35 °C to 95 °C and an increase in sodium citrate (SC concentration from 50 to 650 g/L. In comparison, increasing the citric acid/sodium citrate molar ratio inhibited this leaching. Controlled crystallization through cooling the solution or adjusting the pH of the solution can effectively produce lead citrate crystals. The X-ray diffraction patterns of four products obtained in a comparison test were all consistent with Pb3(C6H5O72. However, the scanning electron microscopy analysis suggested that the morphology was distinct from rods to sheets, which were mainly affected by the temperature variation.

  19. Recovery of Vanadium from H2SO4-HF Acidic Leaching Solution of Black Shale by Solvent Extraction and Precipitation

    OpenAIRE

    Xingbin Li; Chang Wei; Zhigan Deng; Cunxiong Li; Gang Fan; Minting Li; Hui Huang

    2016-01-01

    The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on the extraction and recovery of vanadium was studied. Vanadium (IV) was selectively extracted using a mixture of ...

  20. Banana peel reductant for leaching medium grade manganese ore in sulfuric acid solution

    Science.gov (United States)

    Aripin, H.; Joni, I. Made; Busaeri, Nundang; Usrah, Ifkar; Sudiana, I. Nyoman; Sabchevski, Svilen

    2017-03-01

    In this investigation, manganese has been produced from medium grade manganese ore from Karangnunggal mine (West Java, Indonesia). The effects of weighed amount of banana peels on the structural and leaching properties have been studied. The material's properties have been characterized on the basis of the experimental data obtained using X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier transforms infrared (FTIR) spectroscopy. It has been found that an increase of the weighed amount of banana peels up to 4 g leads to an increase of the leaching efficiency of manganese from manganese ore. Above 4 g, however, the leaching efficiency does not change significantly. The analysis based on the interpretation of both XRD patterns and FTIR spectrum allows one to explain the increase in the leaching efficiencies of manganese by the reduction of MnO2 minerals and by the removal of hemicelluloses groups of banana peel in the samples.

  1. Enhancement of gold grade through arsenic removal in the gold concentrate using sulfuric acid baking and hot water leaching

    Science.gov (United States)

    On, Hyun-sung; Lim, Dae-hack; Myung, Eun-ji; Kim, Hyun-soo; Park, Cheon-young

    2017-04-01

    In order to improve gold recovery, in general, the roasting process is carried out on gold concentrate. However in this process, Arsenic(As) is released from the gold concentrate and valuable elements such as Fe, Cu, Zn and Pb are converted into oxides. This causes air pollution through the release of As and loss of valuable elements by discarding the oxide minerals in the tailings. In order to prevent the release of As and the loss of valuable metals, an acid baking experiment was carried out on the gold concentrate with the addition of an H2SO4 solution. The baking effect, H2SO4 concentration effect and the effects of changing the baking time were examined using an electric furnace. In experimental results, soluble metal sulfates such as Rhomboclase and Mikasite were formed in the baked samples as seen through XRD analysis. In hot(70 degree Celsius) water leaching of the roast and baked samples, As the contents leached were 60 times more in the baked sample than the roast sample, and the Fe, Cu, Zn and Pb contents were 17, 10, 14, 13 times in the baked sample than in the roast sample, respectively. In the water leached solid-residues, the maximum gold grade was upgraded by 33% due to the acid baking effect. It is confirmed that acid baking with H2SO4 prevented As release into the air and the recovery of valuable metals through hot water leaching such as Fe, Cu, Zn and Pb which were formerly discarded in the tailings. Acknowledgment : This work was supported by the Energy and Resources Engineering Program Grant funded by the Ministry of Trade, Industry and Energy, Korea

  2. Effect of a low-viscosity adhesive resin on the adhesion of metal brackets to enamel etched with hydrochloric or phosphoric acid combined with conventional adhesives.

    Science.gov (United States)

    Yetkiner, Enver; Ozcan, Mutlu; Wegehaupt, Florian Just; Wiegand, Annette; Eden, Ece; Attin, Thomas

    2013-12-01

    This study investigated the effect of a low-viscosity adhesive resin (Icon) applied after either hydrochloric (HCl) or phosphoric acid (H3PO4) on the adhesion of metal brackets to enamel. Failure types were analyzed. The crowns of bovine incisors (N = 20) were sectioned mesio-distally and inciso-gingivally, then randomly assigned to 4 groups according to the following protocols to receive mandibular incisor brackets: 1) H3PO4 (37%)+TransbondXT (3M UNITEK); 2) H3PO4 (37%)+Icon+TransbondXT; 3) HCl (15%)+Icon (DMG)+TransbondXT 4) HCl (15%)+Icon+Heliobond (Ivoclar Vivadent)+TransbondXT. Specimens were stored in distilled water at 37°C for 24 h and thermocycled (5000x, 5°C to 55°C). The shear bond strength (SBS) test was performed using a universal testing machine (1 mm/min). Failure types were classified according to the Adhesive Remnant Index (ARI). Contact angles of adhesive resins were measured (n = 5 per adhesive) on ceramic surfaces. No significant difference in SBS was observed, implying no difference between combinations of adhesive resins and etching agents (p = 0.712; ANOVA). The Weibull distribution presented significantly lower Weibull modulus (m) of group 3 (m = 2.97) compared to other groups (m = 5.2 to 6.6) (p group 1 (45.4 ± 7.9) > group 2 (44.2 ± 10.6) > group 3 (42.6 ± 15.5). While in groups 1, 3, and 4 exclusively an ARI score of 0 (no adhesive left on tooth) was observed, in group 2, only one specimen demonstrated score 1 (less than half of adhesive left on tooth). Contact angle measurements were as follows: Icon (25.86 ± 3.81 degrees), Heliobond (31.98 ± 3.17 degrees), TransbondXT (35 ± 2.21 degrees). Icon can be safely used with the conventional adhesives tested on surfaces etched with either HCl or H3PO4.

  3. Evaluation of sampling methods for measuring exposure to volatile inorganic acids in workplace air. Part 1: sampling hydrochloric acid (HCl) and nitric acid (HNO₃) from a test gas atmosphere.

    Science.gov (United States)

    Howe, Alan; Musgrove, Darren; Breuer, Dietmar; Gusbeth, Krista; Moritz, Andreas; Demange, Martine; Oury, Véronique; Rousset, Davy; Dorotte, Michel

    2011-08-01

    Historically, workplace exposure to the volatile inorganic acids hydrochloric acid (HCl) and nitric acid (HNO(3)) has been determined mostly by collection on silica gel sorbent tubes and analysis of the corresponding anions by ion chromatography (IC). However, HCl and HNO(3) can be present in workplace air in the form of mist as well as vapor, so it is important to sample the inhalable fraction of airborne particles. As sorbent tubes exhibit a low sampling efficiency for inhalable particles, a more suitable method was required. This is the first of two articles on "Evaluation of Sampling Methods for Measuring Exposure to Volatile Inorganic Acids in Workplace Air" and describes collaborative sampling exercises carried out to evaluate an alternative method for sampling HCl and HNO(3) using sodium carbonate-impregnated filters. The second article describes sampling capacity and breakthrough tests. The method was found to perform well and a quartz fiber filter impregnated with 500 μL of 1 M Na(2)CO(3) (10% (m/v) Na(2)CO(3)) was found to have sufficient sampling capacity for use in workplace air measurement. A pre-filter is required to remove particulate chlorides and nitrates that when present would otherwise result in a positive interference. A GSP sampler fitted with a plastic cone, a closed face cassette, or a plastic IOM sampler were all found to be suitable for mounting the pre-filter and sampling filter(s), but care has to be taken with the IOM sampler to ensure that the sampler is tightly closed to avoid leaks. HCl and HNO(3) can react with co-sampled particulate matter on the pre-filter, e.g., zinc oxide, leading to low results, and stronger acids can react with particulate chlorides and nitrates removed by the pre-filter to liberate HCl and HNO(3), which are subsequently collected on the sampling filter, leading to high results. However, although there is this potential for both positive and negative interferences in the measurement, these are unavoidable

  4. The Effect of Secondary Refining on the Removal of Phosphorus from Metallurgical-Grade Silicon by Acid Leaching

    Science.gov (United States)

    Lu, Haifei; Wei, Kuixian; Ma, Wenhui; Xie, Keqiang; Wu, Jijun; Lei, Yun

    2017-10-01

    The effects of structural composition, particle size, leaching time, temperature, and liquid-solid ratio on the removal of phosphorus from metallurgical-grade silicon (MG-Si) by acid leaching were investigated. Two specimens with different phase constitutions were studied: crude metallurgical-grade silicon (C-MG-Si), which is reduced from electric arc furnace, with a high content of Al and Ca, and a secondary refined metallurgical-grade silicon (S-MG-Si) obtained after secondary refining in ladle. Using scanning electron microscopy-energy dispersive spectroscopy, the phosphorus-containing phase was only detected in the C-MG-Si grain boundaries. The Si2Al2Ca phase, which was soluble in HCl, showed an affinity for phosphorus, with up to 0.53 wt pct dissolved in this phase. The optimum conditions for acid leaching were grain size, 75-106 μm; leaching time, 6 hours; leaching temperature, 338 K (65 °C); liquid-solid ratio, 6:1; and HCl concentration, 4.0 mol L-1. Using these conditions, the mass fractions of P in C-MG-Si and S-MG-Si were reduced from 105 × 10-6 and 76 × 10-6 to 48 × 10-6 and 61 × 10-6, respectively, with removal efficiencies of 54.3 and 19.7 pct, respectively. Besides, the investigation suggested that adding HF was beneficial for the removal of most impurities. After 6 hours of leaching MG-Si with a mixture composed of 4.0 mol L-1 HCl and 3.0 mol L-1 HF, the purity of C-MG-Si and S-MG-Si were increased from 97.55 and 99.31 pct to 99.91 and 99.87 pct, respectively, with extraction efficiencies of 96.14 and 81.59 pct, respectively. The etching results reveal that the HCl-HF mixture was an effective lixiviant for dissolving impurity inclusions in both C-MG-Si and S-MG-Si.

  5. Study on indium leaching from mechanically activated hard zinc residue

    Directory of Open Access Journals (Sweden)

    Yao J.H.

    2011-01-01

    Full Text Available In this study, changes in physicochemical properties and leachability of indium from mechanically activated hard zinc residue by planetary mill were investigated. The results showed that mechanical activation increased specific surface area, reaction activity of hard zinc residue, and decreased its particle size, which had a positive effect on indium extraction from hard zinc residue in hydrochloric acid solution. Kinetics of indium leaching from unmilled and activated hard zinc residue were also investigated, respectively. It was found that temperature had an obvious effect on indium leaching rate. Two different kinetic models corresponding to reactions which are diffusion controlled, [1-(1- x1/3]2=kt and (1-2x/3-(1-x2/3=kt were used to describe the kinetics of indium leaching from unmilled sample and activated sample, respectively. Their activation energies were determined to be 17.89 kJ/mol (umilled and 11.65 kJ/mol (activated within the temperature range of 30°C to 90°C, which is characteristic for a diffusion controlled process. The values of activation energy demonstrated that the leaching reaction of indium became less sensitive to temperature after hard zinc residue mechanically activated by planetary mill.

  6. Long-Term Acid-Generating and Metal Leaching Potential of a Sub-Arctic Oil Shale

    Directory of Open Access Journals (Sweden)

    Kathryn A. Mumford

    2014-04-01

    Full Text Available Shales are increasingly being exploited for oil and unconventional gas. Exploitation of sub-arctic oil shales requires the creation of gravel pads to elevate workings above the heaving effects of ground ice. These gravel pads can potentially generate acidic leachate, which can enhance the mobility of metals from the shale. To examine this potential, pyrite-bearing shale originating from sub-Arctic gravel pad sites were subjected to leaching tests for 600 days at initial pH values ranging from 2 to 5, to simulate potential real world conditions. At set times over the 600 day experiment, pH, oxidation reduction potential (ORP, dissolved oxygen and temperature were recorded and small liquid samples withdrawn and analysed for elemental concentrations using total reflection X-ray fluorescence spectrometry (TRXRF. Six of eight shale samples were found to be acid generating, with pH declining and ORP becoming increasingly positive after 100 days. Two of the eight shale samples produced increasingly alkaline leachate conditions with relatively low ORP after 100 days, indicating an inbuilt buffering capacity. By 600 days the buffering capacity of all samples had been consumed and all leachate samples were acidic. TRXRF analyses demonstrated significant potential for the leaching of S, Fe, Ni, Cu, Zn and Mn with greatest concentrations found in reaction vessels with most acidic pH and highest ORP.

  7. Hazardous waste to materials: recovery of molybdenum and vanadium from acidic leach liquor of spent hydroprocessing catalyst using alamine 308.

    Science.gov (United States)

    Sahu, K K; Agrawal, Archana; Mishra, D

    2013-08-15

    Recovery of valuable materials/metals from waste goes hand in hand with environmental protection. This paper deals with the development of a process for the recovery of metals such as Mo, V, Ni, Al from spent hydroprocessing catalyst which may otherwise cause a nuisance if dumped untreated. A detailed study on the separation of molybdenum and vanadium from the leach solution of spent hydroprocessing catalyst of composition: 27.15% MoO₃, 1.7% V₂O₅, 3.75% NiO, 54.3% Al₂O₃, 2.3% SiO₂ and 10.4% LOI is reported in this paper. The catalyst was subjected to roasting under oxidizing atmosphere at a temperature of about 550 °C and leaching in dilute sulphuric acid to dissolve molybdenum, vanadium, nickel and part of aluminium. Metals from the leach solution were separated by solvent extraction. Both molybdenum and vanadium were selectively extracted with a suitable organic solvent leaving nickel and dissolved aluminium in the raffinate. Various parameters such as initial pH of the aqueous feed, organic to aqueous ratio (O:A), solvent concentration etc. were optimized for the complete extraction and recovery of Mo and V. Molybdenum and vanadium from the loaded organic were stripped by ammonia solution. They were recovered as their corresponding ammonium salt by selective precipitation, and were further calcined to get the corresponding oxides in pure form. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Acid decomposition and thiourea leaching of silver from hazardous jarosite residues: Effect of some cations on the stability of the thiourea system.

    Science.gov (United States)

    Calla-Choque, D; Nava-Alonso, F; Fuentes-Aceituno, J C

    2016-11-05

    The recovery of silver from hazardous jarosite residues was studied employing thiourea as leaching agent at acid pH and 90°C. The stability of the thiourea in synthetic solutions was evaluated in the presence of some cations that can be present in this leaching system: cupric and ferric ions as oxidant species, and zinc, lead and iron as divalent ions. Two silver leaching methods were studied: the simultaneous jarosite decomposition-silver leaching, and the jarosite decomposition followed by the silver leaching. The study with synthetic solutions demonstrated that cupric and ferric ions have a negative effect on thiourea stability due to their oxidant properties. The effect of cupric ions is more significant than the effect of ferric ions; other studied cations (Fe(2+), Zn(2+), Pb(2+)) had no effect on the stability of thiourea. When the decomposition of jarosite and the silver leaching are carried out simultaneously, 70% of the silver can be recovered. When the acid decomposition was performed at pH 0.5 followed by the leaching step at pH 1, total silver recovery increased up to 90%. The zinc is completely dissolved with any of these processes while the lead is practically insoluble with these systems producing a lead-rich residue. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Experimental investigation of influence of acid rain on leaching and hydraulic characteristics of cement-based solidified/stabilized lead contaminated clay.

    Science.gov (United States)

    Du, Yan-Jun; Jiang, Ning-Jun; Shen, Shui-Long; Jin, Fei

    2012-07-30

    Remediation of contaminated lands in China urban areas is of great concern. Degradation of construction facilities caused by acid rain is a serious environmental pollution issue in China. This paper presents an investigation of the effects of acid rain on leaching and hydraulic properties of cement-based solidified/stabilized lead contaminated soil. Laboratory tests including infiltration test and soaking test are conducted. It is found that the soil hydraulic conductivity decreases with increase in the pore volume of flow of permeant liquids (acid rain and distilled water). The decreasing rate in the case of the acid rain is lower than that in the case of the distilled water. The soaking test results show that pH and the presence of sulfate ions of acid rain have considerable influence on the leached concentrations and leaching rate of calcium. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Investigation of adsorption and inhibitive effect of acid red GRE (183 dye on the corrosion of carbon steel in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    M. Abd El-raouf

    2015-09-01

    Full Text Available The adsorption and corrosion inhibitive effect of acid red GRE (183 dye on carbon steel alloy in 1 M HCl solutions was studied using various techniques. Results of weight loss, Tafel polarization measurements and electrochemical impedance spectroscopy (EIS techniques show that this compound has fairly good inhibiting properties for steel corrosion in acidic bath; with efficiency around 96% at a concentration of 50 ppm. The inhibition is of a mixed anodic–cathodic nature. Factors affecting the corrosion process have been calculated and discussed. Acid red GRE (183 dye was shown to be an inhibitor in the acidic corrosion. Inhibition efficiency increased with acid red GRE (183 dye concentration but decreased with rise in temperature, corrosion inhibition is attributed to the adsorption of acid red GRE (183 dye on the carbon steel surface via a physical adsorption mechanism. Langmuir isotherm is found to provide an accurate description of the adsorption behavior of the investigated azo compound. The nature of the protective film was investigated using SEM and EDX techniques.

  11. Cell cycle profiling by image and flow cytometry: The optimised protocol for the detection of replicational activity using 5-Bromo-2'-deoxyuridine, low concentration of hydrochloric acid and exonuclease III.

    Science.gov (United States)

    Ligasová, Anna; Konečný, Petr; Frydrych, Ivo; Koberna, Karel

    2017-01-01

    The approach for the detection of replicational activity in cells using 5-bromo-2'-deoxyuridine, a low concentration of hydrochloric acid and exonuclease III is presented in the study. The described method was optimised with the aim to provide a fast and robust tool for the detection of DNA synthesis with minimal impact on the cellular structures using image and flow cytometry. The approach is based on the introduction of breaks into the DNA by the low concentration of hydrochloric acid followed by the subsequent enzymatic extension of these breaks using exonuclease III. Our data showed that the method has only a minimal effect on the tested protein localisations and is applicable both for formaldehyde- and ethanol-fixed cells. The approach partially also preserves the fluorescence of the fluorescent proteins in the HeLa cells expressing Fluorescent Ubiquitin Cell Cycle Indicator. In the case of the short labelling pulses that disabled the use of 5-ethynyl-2'-deoxyuridine because of the low specific signal, the described method provided a bright signal enabling reliable recognition of replicating cells. The optimized protocol was also successfully tested for the detection of trifluridine, the nucleoside used as an antiviral drug and in combination with tipiracil also for the treatment of some types of cancer.

  12. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C; Schroeder, Karl T; Chapman, Elizabeth C; Spivak-Birndorf, Lev J; Vesper, Dorothy J; Cardone, Carol R; Rohar, Paul C

    2013-05-01

    The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.

  13. Mechanisms of Vanadium Recovery from Stone Coal by Novel BaCO3/CaO Composite Additive Roasting and Acid Leaching Technology

    Directory of Open Access Journals (Sweden)

    Zhenlei Cai

    2016-03-01

    Full Text Available In this report, the vanadium recovery mechanisms by novel BaCO3/CaO composite additive roasting and acid leaching technology, including the phase transformations and the vanadium leaching kinetics, were studied. The purpose of this manuscript is to realize and improve the vanadium recovery from stone coal using BaCO3/CaO as the composite additive. The results indicated that during the composite additive BaCO3/CaO roasting process, the monoclinic crystalline structure of muscovite (K(Al,V2[Si3AlO10](OH2 was converted into the hexagonal crystalline structure of BaSi4O9 and the tetragonal crystalline structure of Gehlenite (Ca2Al2SiO7, which could, therefore, facilitate the release and extraction of vanadium. Vanadium in leaching residue was probably in the form of vanadate or pyrovanadate of barium and calcium, which were hardly extracted during the sulfuric acid leaching process. The vanadium leaching kinetic analysis indicated that the leaching process was controlled by the diffusion through a product layer. The apparent activation energy could be achieved as 46.51 kJ/mol. The reaction order with respect to the sulfuric acid concentration was 1.1059. The kinetic model of vanadium recovery from stone coal using novel composite additive BaCO3/CaO could be finally established.

  14. Alteration of the phospho- or neutral lipid content and fatty acid composition in Listeria monocytogenes due to acid adaptation mechanisms for hydrochloric, acetic and lactic acids at pH 5.5 or benzoic acid at neutral pH.

    Science.gov (United States)

    Mastronicolis, Sofia K; Berberi, Anita; Diakogiannis, Ioannis; Petrova, Evanthia; Kiaki, Irene; Baltzi, Triantafillia; Xenikakis, Polydoros

    2010-10-01

    This study provides a first approach to observe the effects on Listeria monocytogenes of cellular exposure to acid stress at low or neutral pH, notably how phospho- or neutral lipids are involved in this mechanism, besides the fatty acid profile alteration. A thorough investigation of the composition of polar and neutral lipids from L. monocytogenes grown at pH 5.5 in presence of hydrochloric, acetic and lactic acids, or at neutral pH 7.3 in presence of benzoic acid, is described relative to cells grown in acid-free medium. The results showed that only low pH values enhance the antimicrobial activity of an acid. We suggest that, irrespective of pH, the acid adaptation response will lead to a similar alteration in fatty acid composition [decreasing the ratio of branched chain/saturated straight fatty acids of total lipids], mainly originating from the neutral lipid class of adapted cultures. Acid adaptation in L. monocytogenes was correlated with a decrease in total lipid phosphorus and, with the exception of cells adapted to benzoic acid, this change in the amount of phosphorus reflected a higher content of the neutral lipid class. Upon acetic or benzoic acid stress the lipid phosphorus proportion was analysed in the main phospholipids present: cardiolipin, phosphatidylglycerol, phosphoaminolipid and phosphatidylinositol. Interestingly only benzoic acid had a dramatic effect on the relative quantities of these four phospholipids.

  15. Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process.

    Science.gov (United States)

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2013-05-01

    Waste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420°C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440°C. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Recovery of Vanadium from H2SO4-HF Acidic Leaching Solution of Black Shale by Solvent Extraction and Precipitation

    Directory of Open Access Journals (Sweden)

    Xingbin Li

    2016-03-01

    Full Text Available The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on the extraction and recovery of vanadium was studied. Vanadium (IV was selectively extracted using a mixture of 10% (v/v di(2-ethylhexylphosphoric acid and 5% (v/v tri-n-butylphosphate in sulfonated kerosene. Using six extraction and five stripping stages, the extraction efficiency for vanadium was 96.7% and the stripping efficiency was 99.7%. V2O5 with a purity of 99.52% was obtained by oxidation of the loaded strip solution and precipitation of ammonium polyvanadate at pH 1.8 to 2.2, followed by calcination of the dried precipitate at 550 °C for 2 h. It was concluded that the combination of solvent extraction and precipitation is an efficient method for the recovery of vanadium from a multi-element leach solution generated from black shale.

  17. An integrated experimental-modeling approach to study the acid leaching behavior of lead from sub-micrometer lead silicate glass particles

    Energy Technology Data Exchange (ETDEWEB)

    Elteren, Johannes T. van, E-mail: elteren@ki.si [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Grilc, Miha [Laboratory of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Beeston, Michael P. [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); TSI GmbH, Neuköllner Str. 4, 52068 Aachen (Germany); Reig, Milagros Santacatalina [General Foundation, University of Alicante, E-03690 San Vicente del Raspeig (Alicante) (Spain); Department of Chemical Engineering, University of Alicante, P.O. Box 99, E-03080 Alicante (Spain); Grgić, Irena [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)

    2013-11-15

    Highlights: • Generation of particles by laser ablation of lead silicate glass. • Collection of particles on filters and continuous acid leaching and ICP-MS monitoring. • Fitting of the lead leaching profile to a mathematical intraparticle diffusion model. • Extraction of individual leaching profiles for selected mono-dispersed size fractions. • Leaching kinetics is based on ion-exchange and correlated with particle size. -- Abstract: This work focuses on the development of a procedure to study the mechanism of leaching of lead from sub-micrometer lead glass particles using 0.3 mol l{sup −1} HNO{sub 3} as a leachant. Glass particles with an effective size distribution range from 0.05 to 1.4 μm were generated by laser ablation (213 nm Nd:YAG laser) and collected on an inline 0.2 μm syringe filter. Subsequently, the glass particles on the filter were subjected to online leaching and continuous monitoring of lead (Pb-208) in the leachate by quadrupole ICP-MS. The lead leaching profile, aided by the particle size distribution information from cascade impaction, was numerically fitted to a mathematical model based on the glass intraparticle diffusion, liquid film distribution and thermodynamic glass-leachant distribution equilibrium. The findings of the modeling show that the rate-limiting step of leaching is the migration of lead from the core to the surface of the glass particle by an ion-exchange mechanism, governed by the apparent intraparticle lead diffusivity in glass which was calculated to be 3.1 × 10{sup −18} m{sup 2} s{sup −1}. Lead leaching is illustrated in the form of graphs and animations of intraparticle lead release (in time and intraparticle position) from particles with sizes of 0.1 and 0.3 μm.

  18. Recovery of nickel from spent NiO/Al2O3 catalyst through sulfuric acid leaching, precipitation and solvent extraction.

    Science.gov (United States)

    Nazemi, M K; Rashchi, F

    2012-05-01

    Effective recovery of nickel (Ni) from spent NiO/Al(2)O(3) catalyst in a simple hydrometallurgical route is suggested. Nickel recovery of 99.5% was achieved with sulfuric acid leaching. The leach liquor was partly neutralized and nickel ammonium sulfate was precipitated by adding ammonia. The nickel in the supernatant was concentrated by solvent extraction using D2EHPA and subsequently stripped back into sulfuric acid and returned to the precipitation stage. Necessary counter current extraction and stripping stages were determined in McCabe-Thiele diagrams. The suggested method appears simple and very effective in recovering nickel from spent catalysts from the petrochemical industry.

  19. Recovery of lead from smelting fly ash of waste lead-acid battery by leaching and electrowinning.

    Science.gov (United States)

    Chen, Chuh-Shun; Shih, Yu-Jen; Huang, Yao-Hui

    2016-06-01

    Fly ash that was enriched with lead (Pb), formed as an intermediate in waste lead-acid battery (WLAB) smelting, was recycled by the hydro-electrometallurgy. Characterization of fly ash thereof indicated that the Pb was in the forms of PbSO4 (anglesite) and Pb2OSO4 (lanarkite). Nitric acid and sodium hydroxide were firstly used to study the leaching of the fly ash sample, which was affected by leachant dosage and solid-to-liquid ratio (S/L). At an S/L of 60gL(-1), the leachability of Pb was 43% and 67% in 2M acidic and basic solutions, respectively, based on an average 70wt% of Pb in the original fly ash. Anglesite was completely soluble in NaOH and lanarkite was mildly soluble in HNO3. Pb was recovered from the pregnant leach solution within an electrolytic cell constructed with graphite or RuO2/IrO2-coated titanium (Ti-DSA) anodes and a stainless steel cathode. Properties of anodes deposited with lead dioxides were analyzed by cyclic voltammetry. The optimized parameters of electrowinning were 2M NaOH leachant, a current density of 0.75Adm(-2) and an electrolytic process duration of 120min, which yielded a Pb removal of higher than 99% and a specific energy consumption of 0.57Whg(-1). This process constitutes an eco-friendly and economic alternative to the presently utilized secondary pyrometallurgy for treating lead-containing fly ash. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Demonstration of the efficiency and robustness of an acid leaching process to remove metals from various CCA-treated wood samples.

    Science.gov (United States)

    Coudert, Lucie; Blais, Jean-François; Mercier, Guy; Cooper, Paul; Janin, Amélie; Gastonguay, Louis

    2014-01-01

    In recent years, an efficient and economically attractive leaching process has been developed to remove metals from copper-based treated wood wastes. This study explored the applicability of this leaching process using chromated copper arsenate (CCA) treated wood samples with different initial metal loading and elapsed time between wood preservation treatment and remediation. The sulfuric acid leaching process resulted in the solubilization of more than 87% of the As, 70% of the Cr, and 76% of the Cu from CCA-chips and in the solubilization of more than 96% of the As, 78% of the Cr and 91% of the Cu from CCA-sawdust. The results showed that the performance of this leaching process might be influenced by the initial metal loading of the treated wood wastes and the elapsed time between preservation treatment and remediation. The effluents generated during the leaching steps were treated by precipitation-coagulation to satisfy the regulations for effluent discharge in municipal sewers. Precipitation using ferric chloride and sodium hydroxide was highly efficient, removing more than 99% of the As, Cr, and Cu. It appears that this leaching process can be successfully applied to remove metals from different CCA-treated wood samples and then from the effluents. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Comparison of ultrasonic-assisted and regular leaching of germanium from by-product of zinc metallurgy.

    Science.gov (United States)

    Zhang, Libo; Guo, Wenqian; Peng, Jinhui; Li, Jing; Lin, Guo; Yu, Xia

    2016-07-01

    A major source of germanium recovery and also the source of this research is the by-product of lead and zinc metallurgical process. The primary purpose of the research is to investigate the effects of ultrasonic assisted and regular methods on the leaching yield of germanium from roasted slag containing germanium. In the study, the HCl-CaCl2 mixed solution is adopted as the reacting system and the Ca(ClO)2 used as the oxidant. Through six single factor (leaching time, temperature, amount of Ca(ClO)2, acid concentration, concentration of CaCl2 solution, ultrasonic power) experiments and the comparison of the two methods, it is found the optimum collective of germanium for ultrasonic-assisted method is obtained at temperature 80 °C for a leaching duration of 40 min. The optimum concentration for hydrochloric acid, CaCl2 and oxidizing agent are identified to be 3.5 mol/L, 150 g/L and 58.33 g/L, respectively. In addition, 700 W is the best ultrasonic power and an over-high power is adverse in the leaching process. Under the optimum condition, the recovery of germanium could reach up to 92.7%. While, the optimum leaching condition for regular leaching method is same to ultrasonic-assisted method, except regular method consume 100 min and the leaching rate of Ge 88.35% is lower about 4.35%. All in all, the experiment manifests that the leaching time can be reduced by as much as 60% and the leaching rate of Ge can be increased by 3-5% with the application of ultrasonic tool, which is mainly thanks to the mechanical action of ultrasonic. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Resistance evaluation expanded perlite the leaching acid: variation of parameters concentration, time and leaching agent; Avaliacao da resistencia da perlita expandida a lixiviacao acida: variacao dos parametros concentracao, tempo e agente lixiviante

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, J.M.F. de; Damasceno Junior, E.; Oliveira, E.S.; Fernandes, N.S., E-mail: janielequimicaufrn@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Instituto de Quimica. Laboratorio de Quimica Analitica e Meio Ambiente

    2016-07-01

    The expanded perlite is an amorphous aluminosilicate which presents in its composition about 75.0% silicon oxide (SiO2), also having other species in the composition as oxides of some metals. Silicas and silicates have been used in the environmental field, in relevant anti-corrosive activity. In this context, materials that exposes too many highly acidic media, require preservation against this type of wear, as this type of damage causes a great financial loss, thereby requiring low-cost, abundant materials, non-toxic and easy to purchase as some silica coating. The study evaluated the perlite expanded resistance against an acid leaching process. With undeniability the use of strong acids and different working conditions were not able to remove the oxides present on the expanded perlite sample, thus demonstrating the high strength of the expanded perlite against acid attacks. (author)

  3. Simultaneous leaching of Pt, Pd and Rh from automotive catalytic converters in chloride-containing solutions

    Science.gov (United States)

    Hasani, M.; Khodadadi, A.; Koleini, S. M. J.; Saeedi, A. H.; Meléndez, A. M.

    2017-01-01

    Dissolution of platinum group metals (PGM; herein Pt, Pd and Rh) in different chloride-based leaching systems from spent auto catalysts was performed. Response surface methodology and a five-level-five-factor central composite design were used to evaluate the effects of 1) temperature, 2) liquid-to-solid ratio, 3) stirring speed, 4) acid concentration and 5) particle size on extraction yield of PGM by aqua regia. Analysis of variance was used to determine the optimum conditions and most significant factors affecting the overall metal extraction. In the optimum conditions, leaching of Pt, Pd and Rh was 91.58%, 93.49% and 60.15%, respectively. The effect of different oxidizing agents on the PGM dissolution in chloride medium was studied comparatively in the following leaching systems: a) aqua regia/sulfuric acid mixture, b) hydrogen peroxide in sulfuric acid (piranha solution), c) sodium hypochlorite and d) copper(II). Dissolution of Rh is increased in both aqua regia and hydrogen peroxide/hydrochloric acid solutions by adding sulfuric acid.

  4. Ionic-Liquid-Based Acidic Aqueous Biphasic Systems for Simultaneous Leaching and Extraction of Metallic Ions.

    Science.gov (United States)

    Gras, Matthieu; Papaiconomou, Nicolas; Schaeffer, Nicolas; Chainet, Eric; Tedjar, Farouk; Coutinho, Joao A P; Billard, Isabelle

    2017-11-27

    The first instance of an acidic aqueous biphasic system (AcABS) based on tributyltetradecyl phosphonium chloride ([P44414 ][Cl]) and an acid is here reported. This AcABS exhibits pronounced thermomorphic behavior and is shown to be applicable to the extraction of metal ions from concentrated acidic solutions. Metal ions such as cobalt(II), iron(III), platinum(IV) and nickel(II) are found to partition preferentially to one of the phases of the acidic aqueous biphasic system and it is here shown that it successfully allows the difficult separation of CoII from NiII , here studied at 24 and 50 °C. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Comparative sorption and leaching study of the herbicides fluometuron and 4-chloro-2-methylphenoxyacetic acid (MCPA) in a soil amended with biochars and other sorbents.

    Science.gov (United States)

    Cabrera, Alegria; Cox, Lucia; Spokas, Kurt A; Celis, Rafael; Hermosín, M Carmen; Cornejo, Juan; Koskinen, William C

    2011-12-14

    Biochar, the solid residual remaining after the thermochemical transformation of biomass for carbon sequestration, has been proposed to be used as a soil amendment, because of its agronomic benefits. The effect of amending soil with six biochars made from different feedstocks on the sorption and leaching of fluometuron and 4-chloro-2-methylphenoxyacetic acid (MCPA) was compared to the effect of other sorbents: an activated carbon, a Ca-rich Arizona montmorillonite modified with hexadecyltrimethylammonium organic cation (SA-HDTMA), and an agricultural organic residue from olive oil production (OOW). Soil was amended at 2% (w/w), and studies were performed following a batch equilibration procedure. Sorption of both herbicides increased in all amended soils, but decreased in soil amended with a biochar produced from macadamia nut shells made with fast pyrolysis. Lower leaching of the herbicides was observed in the soils amended with the biochars with higher surface areas BC5 and BC6 and the organoclay (OCl). Despite the increase in herbicide sorption in soils amended with two hardwood biochars (BC1 and BC3) and OOW, leaching of fluometuron and MCPA was enhanced with the addition of these amendments as compared to the unamended soil. The increased leaching is due to some amendments' soluble organic compounds, which compete or associate with herbicide molecules, enhancing their soil mobility. Thus, the results indicate that not all biochar amendments will increase sorption and decrease leaching of fluometuron and MCPA. Furthermore, the amount and composition of the organic carbon (OC) content of the amendment, especially the soluble part (DOC), can play an important role in the sorption and leaching of these herbicides.

  6. Analysis of twenty phenolic compounds in human urine: hydrochloric acid hydrolysis, solid-phase extraction based on K2CO 3-treated silica, and gas chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lu, Dasheng; Feng, Chao; Wang, Dongli; Lin, Yuanjie; Ip, Ho Sai Simon; She, Jianwen; Xu, Qian; Wu, Chunhua; Wang, Guoquan; Zhou, Zhijun

    2015-05-01

    This study developed a new method for the analysis of 20 phenolic compounds in human urine. The urine samples were prepared by hydrochloric acid (HCl) hydrolysis, liquid-liquid extraction (LLE), and solid-phase extraction (SPE) cleanup. We found that HCl hydrolysis is of similar effectiveness to, and much cheaper than, the traditional enzymatic method. Vanillic acid was co-eluted with butyl paraben and interfered with the determination of butyl paraben in urine. K2CO3-treated-silica-gel SPE was designed to efficiently eliminate interference from the endogenous organic acids (especially vanillic acid) in urine. After derivatization, the samples were analyzed by large-volume-injection gas chromatography-tandem mass spectrometry (LVI-GC-MS-MS). Good linearity (R (2) ≥ 0.996) was established in the range 0.1-100 ng mL(-1) for all analytes. Method detection limits (MDLs) were 0.7-9.8 pg mL(-1). Intraday (n = 5) and interday (n = 5 days) validation was performed, with satisfactory accuracy (recovery: 70-126 % and 73-107 %, respectively) and precision (RSD ≤ 19 %) at two levels (low: 0.1 and 0.5 ng mL(-1); high: 5 and 10 ng mL(-1)). The method was used in a population study and achieved more than 85 % detection for most analytes; mean analyte concentrations were in the range 0.01-185 ng mL(-1). The method is suitable for the analysis of multiple phenolic metabolites in human urine.

  7. Leaching of organic acids from macromolecular organic matter by non-supercritical CO2

    Science.gov (United States)

    Sauer, P.; Glombitza, C.; Kallmeyer, J.

    2012-04-01

    The storage of CO2 in underground reservoirs is discussed controversly in the scientific literature. The worldwide search for suitable storage formations also considers coal-bearing strata. CO2 is already injected into seams for enhanced recovery of coal bed methane. However, the effects of increased CO2 concentration, especially on organic matter rich formations, are rarely investigated. The injected CO2 will dissolve in the pore water, causing a decrease in pH and resulting in acidic formation waters. Huge amounts of low molecular weight organic acids (LMWOAs) are chemically bound to the macromolecular matrix of sedimentary organic matter and may be liberated by hydrolysis, which is enhanced by the acidic porewater. Recent investigations outlined the importance of LMWOAs as a feedstock for microbial life in the subsurface [1]. Therefore, injection of CO2 into coal formations may result in enhanced nutrient supply for subsurface microbes. To investigate the effect of high concentrations of dissolved CO2 on the release of LMWOAs from coal we developed an inexpensive high-pressure high temperature system that allows manipulating the partial pressure of dissolved gases at pressures and temperatures up to 60 MPa and 120° C, respectively. In a reservoir vessel, gases are added to saturate the extraction medium to the desired level. Inside the extraction vessel hangs a flexible and inert PVDF sleeve (polyvinylidene fluoride, almost impermeable for gases), holding the sample and separating it from the pressure fluid. The flexibility of the sleeve allows for subsampling without loss of pressure. Coal samples from the DEBITS-1 well, Waikato Basin, NZ (R0 = 0.29, TOC = 30%). were extracted at 90° C and 5 MPa, either with pure or CO2-saturated water. Subsamples were taken at different time points during the extraction. The extracted LMWOAs such as formate, acetate and oxalate were analysed by ion chromatography. Yields of LMWOAs were higher with pure water than with CO2

  8. Synthesis and characterization of Co3O4 prepared from atmospheric pressure acid leach liquors of nickel laterite ores

    Science.gov (United States)

    Meng, Long; Guo, Zhan-cheng; Qu, Jing-kui; Qi, Tao; Guo, Qiang; Hou, Gui-hua; Dong, Peng-yu; Xi, Xin-guo

    2018-01-01

    A chemical precipitation-thermal decomposition method was developed to synthesize Co3O4 nanoparticles using cobalt liquor obtained from the atmospheric pressure acid leaching process of nickel laterite ores. The effects of the precursor reaction temperature, the concentration of Co2+, and the calcination temperature on the specific surface area, morphology, and the electrochemical behavior of the obtained Co3O4 particles were investigated. The precursor basic cobaltous carbonate and cobaltosic oxide products were characterized and analyzed by Fourier transform infrared spectroscopy, thermogravimetric differential thermal analysis, X-ray diffraction, field-emission scanning electron microscopy, specific surface area analysis, and electrochemical analysis. The results indicate that the specific surface area of the Co3O4 particles with a diameter of 30 nm, which were obtained under the optimum conditions of a precursor reaction temperature of 30°C, 0.25 mol/L Co2+, and a calcination temperature of 350°C, was 48.89 m2/g. Electrodes fabricated using Co3O4 nanoparticles exhibited good electrochemical properties, with a specific capacitance of 216.3 F/g at a scan rate of 100 mV/s.

  9. Survival of Salmonella strains differing in their biofilm-formation capability upon exposure to hydrochloric and acetic acid and to high salt.

    Science.gov (United States)

    Hasegawa, Akio; Hara-Kudo, Yukiko; Kumagai, Susumu

    2011-09-01

    Acidic and osmotic treatments are part of hurdle systems to control pathogens such as Salmonella in food. In the current study, Salmonella enterica isolates previously shown to differ in their ability to form biofilms were grown in diluted tryptic soy broth (TSB) (1:5 dilution in distilled water) and subsequently exposed to phosphate-buffered saline (PBS) adjusted to pH 3.0 with HCl, PBS adjusted to pH 3.9 with acetic acid or rice vinegar diluted 1:15 with distilled water (pH 3.9). Cells grown in diluted TSB were also exposed to distilled water, pH 7.6, containing 5 M NaCl. No differences in survival upon exposure to PBS adjusted to pH 3.0 with HCl or distilled water containing high salt were observed between the isolates; however, exposure to acetic acid and rice vinegar resulted in lower survival levels of isolates previously shown to be poor biofilm formers. The numbers (log(10) cfu/ml) of surviving cells after exposure for 36 hr to acetic acid and rice vinegar were 4.43 ± 0.24 vs. 2.27 ± 0.87 (Psurvival data could be fitted with the Weibull model. The data suggest that the ability of Salmonella strains to survive in the presence of acetic acid and rice vinegar parallels their ability to form biofilms. Thus, Salmonella with a high biofilm-formation capability might be more difficult to kill with acetic acid found in foods or cleaning solutions.

  10. The water soluble composite poly(vinylpyrrolidone–methylaniline: A new class of corrosion inhibitors of mild steel in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    R. Karthikaiselvi

    2017-02-01

    Full Text Available In recent years poly methyl aniline has been reported as one of the efficient corrosion inhibitors of mild steel in acidic media. In view of the major limitation of the insolubility of polymethyl aniline PMA, we propose to convert PMA into a water soluble composite using supporting polymer polyvinylpyrrolidone to get higher solubility and corrosion inhibition efficiency. The water soluble composite poly(vinylpyrrolidone-methyl aniline was synthesized by chemical oxidative polymerization and its inhibitive effect on mild steel in 1 M HCl has been investigated using weight loss and electrochemical techniques (potentiodynamic polarization studies and impedance spectroscopy. SEM and EDX analyses are carried out to establish a protective film formation on the metal surface.

  11. Recovery of rare earths from spent NdFeB magnets of wind turbine: Leaching and kinetic aspects.

    Science.gov (United States)

    Kumari, Aarti; Sinha, Manish Kumar; Pramanik, Swati; Sahu, Sushanta Kumar

    2018-01-31

    Increasing demands of rare earth (RE) metals for advanced technological applications coupled with the scarcity of primary resources have led to the development of processes to treat secondary resources like scraps or end of life products that are often rich in such metals. Spent NdFeB magnet may serve as a potential source of rare earths containing around ∼30% of neodymium and other rare earths. In the present investigation, a pyro-hydrometallurgical process has been developed to recover rare earth elements (Nd, Pr and Dy) from the spent wind turbine magnet. The spent magnet is demagnetized and roasted at 1123 K to convert rare earths and iron to their respective oxides. Roasting of the magnet not only provides selectivity, but enhances the leaching efficiency also. The leaching of the roasted sample with 0.5 M hydrochloric acid at 368 K, 100 g/L pulp density and 500 rpm for 300 min selectively recovers the rare earth elements almost quantitatively leaving iron oxide in the residue. Leaching of rare earth elements with hydrochloric acid follows the mixed controlled kinetic model with activation energy (E a ) of 30.1 kJ/mol in the temperature range 348-368 K. The leaching mechanism is further established by characterizing the leach residues obtained at different time intervals by scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD). Individual rare earth elements from the leach solution containing 16.8 g/L of Nd, 3.8 g/L Pr, 0.28 g/L of Dy and other minor impurity elements could be separated by solvent extraction. However, mixed rare earth oxide of 99% purity was produced by oxalate precipitation followed by roasting. The leach residue comprising of pure hematite has a potential to be used as pigment or can find other applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Reduction of oxidative stress may play a role in the anti-inflammatory effect of the novel herbal formulation in a rat model of hydrochloric acid-induced cystitis.

    Science.gov (United States)

    Bae, Woong-Jin; Ha, U-Syn; Kim, Seol; Kim, Su-Jin; Hong, Sung-Hoo; Lee, Ji-Youl; Hwang, Tae-Kon; Hwang, Sung-Yeoun; Kim, Hong-Jun; Kim, Sae-Woong

    2015-01-01

    We investigated the effect of the multi-herbal medicine, WSY-1075 in an animal model of hydrochloric acid (HCl)-induced cystitis. Rats were randomly assigned to three groups: sham-operated (control), HCl-induced only (HC), and HC treated with WSY-1075 (HC + WT). Oral administration of either distilled water (control, HC) or WSY-1075 (400 mg/kg) was continued for 4 weeks. In HC and HC + WT groups, cystitis was induced with 0.4 M HCl beginning on the 22nd day. Rats in each group underwent cystometrography, and bladders were examined for evidence of inflammation and oxidative stress. Treatment with WSY-1075 decreased the frequency of urination and reduced inflammation of the bladder tissue in a rat model of HCl-induced cystitis. Compared with the control group, the HC group showed severe chronic inflammatory and fibrosis signs, and the inflammatory grades significantly decreased following WSY-1075 treatment in the HC-WT group. The HC + WT group showed a markedly decreased expression of pro-inflammatory cytokines compared to the HC group. The level of malondialdehyde was significantly greater in the HC group compared to the control group, and it was significantly reduced in the treated (HC + WT) group. The levels of superoxide dismutase increased in the HC + WT group, which confirmed the anti-oxidant effect of WSY-1075. We suggest that reduction of oxidative stress may play a role in this anti-inflammatory effect. © 2013 Wiley Periodicals, Inc.

  13. ac impedance, X-ray photoelectron spectroscopy and density functional theory studies of 3,5-bis(n-pyridyl)-1,2,4-oxadiazoles as efficient corrosion inhibitors for carbon steel surface in hydrochloric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Outirite, Moha; Lagrenee, Michel; Lebrini, Mounim [Unite de Catalyse et de Chimie du Solide, UMR-CNRS 8181, ENSCL, B.P. 90108, F-59652 Villeneuve d' Ascq Cedex (France); Traisnel, Michel; Jama, Charafeddine [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, PERF UMR-CNRS 8008, ENSCL, B.P. 90108, F-59652 Villeneuve d' Ascq Cedex (France); Vezin, Herve [Laboratoire de Chimie Organique et Macromoleculaire, UMR-CNRS 8009, USTL Bat C4, F-59655 Villeneuve d' Ascq Cedex (France); Bentiss, Fouad, E-mail: fbentiss@enscl.f [Laboratoire de Chimie de Coordination et d' Analytique, Faculte des Sciences, Universite Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco)

    2010-02-01

    The corrosion inhibition properties of a new class of oxadiazole derivatives, namely 3,5-bis(n-pyridyl)-1,2,4-oxadiazoles (n-DPOX) for C38 carbon steel corrosion in 1 M HCl medium were analysed by electrochemical impedance spectroscopy (EIS). An adequate structural model of the interface was used and the values of the corresponding parameters were calculated and discussed. The experimental results showed that these compounds are excellent inhibitors for the C38 steel corrosion in acid solution and that the protection efficiency increased with increasing the inhibitors concentration. Electrochemical impedance data demonstrate that the addition of the n-DPOX derivatives in the corrosive solution decreases the charge capacitance and simultaneously increases the function of the charge/discharge of the interface, facilitating the formation of an adsorbed layer over the steel surface. Adsorption of these inhibitors on the steel surface obeys to the Langmuir adsorption isotherm. X-ray photoelectron spectroscopy (XPS) and the thermodynamic data of adsorption showed that inhibition of steel corrosion in normal hydrochloric solution by n-DPOX is due to the formation of a chemisorbed film on the steel surface. Quantum chemical calculations using the Density Functional Theory (DFT) and the Quantitative Structure Activity Relationship (QSAR) approach were performed on n-DPOX derivatives to determine the relationship between molecular structure and their inhibition efficiencies. The results of the quantum chemical calculations and experimental inhibition efficiency were subjected to correlation analysis and indicate that their inhibition effect is closely related to E{sub HOMO}, E{sub LUMO}, and dipole moment (mu).

  14. Inhibition Effects of a Synthesized Novel 4-Aminoantipyrine Derivative on the Corrosion of Mild Steel in Hydrochloric Acid Solution together with Quantum Chemical Studies

    Directory of Open Access Journals (Sweden)

    Abu Bakar Mohamad

    2013-06-01

    Full Text Available 1,5-Dimethyl-4-((2-methylbenzylideneamino-2-phenyl-1H-pyrazol-3(2H-one (DMPO was synthesized to be evaluated as a corrosion inhibitor. The corrosion inhibitory effects of DMPO on mild steel in 1.0 M HCl were investigated using electrochemical impedance spectroscopy (EIS, potentiodynamic polarization, open circuit potential (OCP and electrochemical frequency modulation (EFM. The results showed that DMPO inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration. Changes in the impedance parameters suggested an adsorption of DMPO onto the mild steel surface, leading to the formation of protective films. The novel synthesized corrosion inhibitor was characterized using UV-Vis, FT-IR and NMR spectral analyses. Electronic properties such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively and dipole moment (μ were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in the EHOMO values but with a decrease in the ELUMO value.

  15. Temporal and spatial variation in the status of acid rivers and potential prevention methods of AS soil-related leaching in peatland forestry

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, T.

    2013-06-01

    This thesis examines temporal and spatial variations in the status of different rivers and streams of western Finland in terms of acidity and sources of acid load derived from the catchment area. It also examines the monitoring of acid runoff water derived from maintenance drainage in peatland forestry and suggests potential mitigation methods. A total of 17 river basins of different sizes in western Finland were selected for study, including rivers affected by both drainage of agricultural AS soils and forested peatlands. Old data from 1911-1931 were available, but most data were from the 1960s onwards and were taken from the HERTTA database. During 2009-2011, pH and conductivity measurements and water sampling were conducted. Biological monitoring for ecological classification was conducted in the Sanginjoki river system during 2008 and 2009. Three peatland forestry sites were selected to study acid leaching via pH and EC measurements and water sampling. Fluctuations in groundwater level in different drainage conditions were simulated and acid leaching was investigated in laboratory experiments in order to replicate a situation where the groundwater level drops and allows oxidation of sulphidic materials. It was found that river pH decreased and metal concentrations increased with runoff. The highest acidity observed coincided with periods of intense drainage in the 1970s and after dry summers in the past decade. Together with pH, electric conductivity and sulphate in river water were identified as suitable indicators of AS soils in a catchment, because they directly respond to acid leaching derived from AS soils. Acidity derived from organic acids was clearly observed in catchments dominated by forested peatlands and wetlands. Temporal and spatial variations in ecological status were observed, but monitoring at whole-catchment scale and during consecutive years is needed to increase the reliability of the results. Simulations on the potential effects of

  16. One-step separation by thermal treatment and cobalt acid-leaching from spent lithium-ion batteries

    Science.gov (United States)

    Mu, Deying

    2017-10-01

    Lithium-ion batteries are extensively used in portable storage devices and automobiles, therefore the environment and resource problems caused by spent lithium ion batteries have become increasingly severe. This paper focuses on the recovery process of spent lithium cobalt oxide active material and comes up with reasonable processes and the best conditions for cobalt leaching ultimately.

  17. Preparation and characterization of TiO2/acid leached serpentinite tailings composites and their photocatalytic reduction of chromium(VI).

    Science.gov (United States)

    Sun, Zhiming; Zheng, Liming; Zheng, Shuilin; Frost, Ray L

    2013-08-15

    Composite TiO2/acid leached serpentine tailings (AST) were synthesized through the hydrolysis-deposition method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and surface area measurement (BET). The XRD analysis showed that TiO2 coated on the surface of acid leached serpentine tailings was mixed crystal phases of rutile and anatase, the grain size of which is 10-30 nm. SEM, TEM, and EDS analysis exhibited that nano-TiO2 particles were deposited on the surface and internal cavities of acid leaching serpentine tailings. The XPS and FT-IR analysis demonstrated that the coating process of TiO2 on AST was a physical adsorption process. The large specific surface area, porous structure, and plentiful surface hydroxyl group of TiO2/AST composite resulted in the high adsorption capacity of Cr(VI). The experimental results demonstrated that initial concentration of Cr(VI), the amount of the catalyst, and pH greatly influenced the removal efficiency of Cr(VI). The removal kinetics of Cr(VI) at a relative low initial concentration was fitted well with Langmuir-Hinshelwood kinetics model with R(2) value of about unity. The as-prepared composites exhibited strong adsorption and photocatalytic capacity for the removal of Cr(VI), and the possible photocatalytic reduction mechanism was studied. The photodecomposition of Cr(VI) was as high as 95% within 2h, and the reusability of the photocatalysis was proven. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Leachability of nitrided ilmenite in hydrochloric acid

    CSIR Research Space (South Africa)

    Swanepoel, JJ

    2010-10-01

    Full Text Available Titanium nitride in upgraded nitrided ilmenite (bulk of iron removed) can selectively be chlorinated to produce titanium tetrachloride. Except for iron, most other components present during this low temperature (ca. 200 °C) chlorination reaction...

  19. Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

    OpenAIRE

    mehdi amini

    2013-01-01

    In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers) and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solu...

  20. Solvent Extraction of Rare Earth Elements from a Nitric Acid Leach Solution of Apatite by Mixtures of Tributyl Phosphate and Di-(2-ethylhexyl) Phosphoric Acid

    Science.gov (United States)

    Ferdowsi, Ali; Yoozbashizadeh, Hossein

    2017-09-01

    Solvent extraction of rare earths from nitrate leach liquor of apatite using mixtures of tributyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was studied. The effects of nitrate and hydrogen ion concentration of the aqueous phase as well as the composition and concentration of extractants in the organic phase on the extraction behavior of lanthanum, cerium, neodymium, and yttrium were investigated. The distribution ratio of REEs increases by increasing the nitrate concentration in aqueous phase and concentration of extractants in organic phase, but the hydrogen ion concentration in aqueous phase has a decreasing effect. Yttrium as a heavy rare earth is more sensitive to these parameters than light rare earth elements. Although the composition of organic phase has a minor effect on the extraction of light rare earths, the percent of extraction of yttrium decreases dramatically by increasing the TBP content of organic phase. Mixtures of TBP and D2EHPA can show either synergism or antagonism extraction depending on the concentration and composition of extractants in organic phase. The best condition for separating rare earth elements in groups of heavy and light REEs can be achieved at high nitrate concentration, low H+ concentration, and high concentration of D2EHPA in organic phase. Separation of Ce and La by TBP and D2EHPA is practically impossible in the studied conditions; however, low nitrate concentration and high hydrogen ion concentration in aqueous phase and low concentration of extractants in organic phase favor the separation of Nd from other light rare earth elements.

  1. Solvent Extraction of Rare Earth Elements from a Nitric Acid Leach Solution of Apatite by Mixtures of Tributyl Phosphate and Di-(2-ethylhexyl) Phosphoric Acid

    Science.gov (United States)

    Ferdowsi, Ali; Yoozbashizadeh, Hossein

    2017-12-01

    Solvent extraction of rare earths from nitrate leach liquor of apatite using mixtures of tributyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was studied. The effects of nitrate and hydrogen ion concentration of the aqueous phase as well as the composition and concentration of extractants in the organic phase on the extraction behavior of lanthanum, cerium, neodymium, and yttrium were investigated. The distribution ratio of REEs increases by increasing the nitrate concentration in aqueous phase and concentration of extractants in organic phase, but the hydrogen ion concentration in aqueous phase has a decreasing effect. Yttrium as a heavy rare earth is more sensitive to these parameters than light rare earth elements. Although the composition of organic phase has a minor effect on the extraction of light rare earths, the percent of extraction of yttrium decreases dramatically by increasing the TBP content of organic phase. Mixtures of TBP and D2EHPA can show either synergism or antagonism extraction depending on the concentration and composition of extractants in organic phase. The best condition for separating rare earth elements in groups of heavy and light REEs can be achieved at high nitrate concentration, low H+ concentration, and high concentration of D2EHPA in organic phase. Separation of Ce and La by TBP and D2EHPA is practically impossible in the studied conditions; however, low nitrate concentration and high hydrogen ion concentration in aqueous phase and low concentration of extractants in organic phase favor the separation of Nd from other light rare earth elements.

  2. A novel method for enhancing on-stream stability of fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst. Post-treatment of HZSM-5 zeolite by combined steaming and citric acid leaching

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Xiuying [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Fan, Yu.; Shi, Gang; Liu, Haiyan [The Key Laboratory of Catalysis, China National Petroleum Co., China University of Petroleum, Beijing 102249 (China); Liu, Zhihong [Science and Technology Management Department, PetroChina Company, Ltd., World Tower, 16 Andelu, Dongcheng District, Beijing 100011 (China); Bao, Xiaojun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); The Key Laboratory of Catalysis, China National Petroleum Co., China University of Petroleum, Beijing 102249 (China)

    2007-07-30

    This article describes a novel modification method consisting of steaming and subsequent citric acid leaching to finely tune acidity and pore structure of HZSM-5 zeolite and thereby to enhance the on-stream stability of the zeolite derived fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst. A series of dealuminated HZSM-5 zeolites and their derived catalysts were prepared and characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), {sup 27}Al MAS NMR, nitrogen adsorption, temperature programmed desorption of ammonium (NH{sub 3}-TPD) and infrared (IR) spectroscopy of chemisorbed pyridine. The results showed that the citric acid leaching could preferentially remove the extra-framework Al (EFAl) species formed by steaming treatment and thus reopen the EFAl-blocked pore channels of the steamed zeolite. The steaming treatment at a suitable temperature and subsequent citric acid leaching not only decreased the strength of acid sites to a desirable degree but also increased the ratio of medium and strong Lewis acidity to medium and strong Broensted acidity, both of which conferred the resulting catalyst with superior selectivity to aromatics, good hydroisomerization activity and gasoline research octane number (RON) preservability, as well as enhanced on-stream stability. The results fully demonstrated that the treatments by steaming and followed citric acid leaching can serve as an important method for adjusting the physicochemical properties of HZSM-5 zeolite. (author)

  3. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment.

    Science.gov (United States)

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2015-07-01

    Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine-iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercritical water, then a diluted hydrochloric acid leaching (HL) process was used to recovery the Cu, whose leaching efficiency was approximately 100%, finally the resulting residue was subjected to the iodine-iodide leaching process for recovering the Au, Ag, and Pd. Experimental results indicated that SCWO pre-treatment temperature, time, and pressure had significant influence on the Au, Ag, and Pd leaching from (SCWO+HL)-treated waste PCBs. The optimal SCWO pre-treatment conditions were 420°C and 60min for Au and Pd, and 410°C and 30min for Ag. The optimum dissolution parameters for Au, Pd, and Ag in (SCWO+HL)-treated PCBs with iodine-iodide system were leaching time of 120min (90min for Ag), iodine/iodide mole ratio of 1:5 (1:6 for Ag), solid-to-liquid ratio (S/L) of 1:10g/mL (1:8g/mL for Ag), and pH of 9, respectively. It is believed that the process developed in this study is environment friendly for the recovery of Au, Ag, and Pd from waste PCBs of mobile phones by SCWO pre-treatment combined with iodine-iodide leaching process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Investigation of electrolyte leaching in the performance degradation of phosphoric acid-doped polybenzimidazole membrane-based high temperature fuel cells

    Science.gov (United States)

    Jeong, Yeon Hun; Oh, Kyeongmin; Ahn, Sungha; Kim, Na Young; Byeon, Ayeong; Park, Hee-Young; Lee, So Young; Park, Hyun S.; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Ju, Hyunchul; Kim, Jin Young

    2017-09-01

    Precise monitoring of electrolyte leaching in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) devices during lifetime tests is helpful in making a diagnosis of their quality changes and analyzing their electrochemical performance degradation. Here, we investigate electrolyte leaching in the performance degradation of phosphoric acid (PA)-doped polybenzimidazole (PBI) membrane-based HT-PEMFCs. We first perform quantitative analyses to measure PA leakage during cell operation by spectrophotometric means, and a higher PA leakage rate is detected when the current density is elevated in the cell. Second, long-term degradation tests under various current densities of the cells and electrochemical impedance spectroscopy (EIS) analysis are performed to examine the influence of PA loss on the membrane and electrodes during cell performance degradation. The combined results indicate that PA leakage affect cell performance durability, mostly due to an increase in charge transfer resistance and a decrease in the electrochemical surface area (ECSA) of the electrodes. Additionally, a three-dimensional (3-D) HT-PEMFC model is applied to a real-scale experimental cell, and is successfully validated against the polarization curves measured during various long-term experiments. The simulation results highlight that the PA loss from the cathode catalyst layer (CL) is a significant contributor to overall performance degradation.

  5. Innovative leaching of cobalt and lithium from spent lithium-ion batteries and simultaneous dechlorination of polyvinyl chloride in subcritical water

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kang; Zhang, Fu-Shen, E-mail: fszhang@rcees.ac.cn

    2016-10-05

    Highlights: • A co-treatment process for recovery of Co and Li and simultaneous detoxification of PVC in subcritical water was proposed. • PVC was used as a hydrochloric acid source. • More than 95% Co and nearly 98% Li were leached under the optimum conditions. • Neither corrosive acid nor reducing agent was used. • The co-treatment process has technical, economic and environmental benefits over the traditional recovery processes. - Abstract: In this work, an effective and environmentally friendly process for the recovery of cobalt (Co) and lithium (Li) from spent lithium-ion batteries (LIBs) and simultaneously detoxification of polyvinyl chloride (PVC) in subcritical water was developed. Lithium cobalt oxide (LiCoO{sub 2}) power from spent LIBs and PVC were co-treated by subcritical water oxidation, in which PVC served as a hydrochloric acid source to promote metal leaching. The dechlorination of PVC and metal leaching was achieved simultaneously under subcritical water oxidation. More than 95% Co and nearly 98% Li were recovered under the optimum conditions: temperature 350 °C, PVC/LiCoO{sub 2} ratio 3:1, time 30 min, and a solid/liquid ratio 16:1 (g/L), respectively. Moreover, PVC was completely dechlorinated at temperatures above 350 °C without any release of toxic chlorinated organic compounds. Assessment on economical and environmental impacts revealed that the PVC and LiCoO{sub 2} subcritical co-treatment process had significant technical, economic and environmental benefits over the traditional hydrometallurgy and pyrometallurgy processes. This innovative co-treatment process is efficient, environmentally friendly and adequate for Co and Li recovery from spent LIBs and simultaneous dechlorination of PVC in subcritical water.

  6. Sulphuric acid leaching of low/medium grade managanese ores using a novel nitrogeneous reductant-NH3NH2HSO4

    Directory of Open Access Journals (Sweden)

    Hariprasad D.

    2013-01-01

    Full Text Available Low and medium grade land as well sea based manganese ores were used for manganese extraction in H2SO4 - NH3NH2HSO4 (hydrazine sulphate medium For land based Mn ores, only Mn recovery is important but for sea nodules which contain substantial amounts Co, Ni, and Cu, their recovery is equally important. In the present studies four samples used were: Indian ocean manganese nodules, medium and low grade Mn ores of Gujarat, and low grade Mn ore of Orissa, India. The Mn content of these ores varied from 15 to 39%. The objective of this work is to establish a reductant which can be used for leaching Mn from all types of ores. The optimum conditions established for nodules by varying parameters such as time, temperature, pulp density, H2SO4 and NH3NH2HSO4 concentrations were: pulp density 10%, time 0.5h, temperature 110ºC, NH3NH2HSO4 3.25 g/10g, H2SO4 2.0% (v/v for 96.9% Mn, 85.25% Cu, 92.58% Ni and 76.5% Co extractions. More than 92% Mn could be leached from different types of ores by varying amount of reductant and acid concentration at 35ºC. Depending on Mn content 1.0 to 1.2 times stochiometric amount of reductant and 1.5 to 1.8 times sulphuric acid were required for >92% Mn extraction.

  7. Leaching studies for metals recovery from waste printed wiring boards

    Science.gov (United States)

    Luyima, Alex; Shi, Honglan; Zhang, Lifeng

    2011-08-01

    The leaching behavior of most metals present in printed wiring boards is evaluated, aiming at its recycling by hydrometallurgy. Two leaching reagents (nitric acid and aqua regia) are compared. The effects of acid concentration, particle size of sample, leaching time, and temperature are examined. The results reveal that small particle size and a combination of both nitric acid and aqua regia are capable of dissolving most of the metals content of printed wiring boards.

  8. Two-Stage Separation of V(IV) and Al(III) by Crystallization and Solvent Extraction from Aluminum-Rich Sulfuric Acid Leaching Solution of Stone Coal

    Science.gov (United States)

    Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing; Liu, Hong

    2017-10-01

    To improve separation of V(IV) and Al(III) from aluminum-rich sulfuric acid leaching solution of stone coal, the two-stage separation by crystallization and solvent extraction methods have been developed. A co-extraction coefficient ( k) was put forward to evaluate comprehensively co-extraction extent in different solutions. In the crystallization stage, 68.2% of aluminum can be removed from the solution. In the solvent extraction stage, vanadium was selectively extracted using di-2-ethylhexyl phosphoric acid/tri-n-butyl phosphate from the crystalline mother solution, followed by H2SO4 stripped efficiently. A V2O5 product with purity of 98.39% and only 0.10% Al was obtained after oxidation, precipitation, and calcination. Compared with vanadium extraction from solution without crystallization, the counter-current extraction stage of vanadium can be decreased from 6 to 3 and co-extraction coefficient ( k) decreased from 2.51 to 0.58 with two-stage separation. It is suggested that the aluminum removal by crystallization can evidently weaken the influence of aluminum co-extraction on vanadium extraction and improve the selectivity of solvent extraction for vanadium.

  9. Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

    Science.gov (United States)

    Swain, Ranjita; Bhima Rao, R.

    2017-08-01

    In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

  10. Research on the effect of alkali roasting of copper dross on leaching rate of indium

    Science.gov (United States)

    Dafang, Liu; Fan, Xingxiang; Shi, Yifeng; Yang, Kunbin

    2017-11-01

    The byproduct copper dross produced during refining crude lead was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectrometer (XRF), which showed that copper dross mainly contained lead, copper, zinc, arsenic, antimony, bismuth, sulfur and a small amount of indium and silver etc. The mineralogical phase change of oxidation roasting of copper dross by adding sodium hydroxide was analyzed with the help of XRD and SEM. The effects of water leaching, ratio of sodium hydroxide, roasting time, and roasting temperature on leaching rate of indium were investigated mainly. The experimental results showed that phase of lead metal and sulfides of lead, copper and zinc disappeared after oxidation roasting of copper dross by adding sodium hydroxide, new phase of oxides of lead, copper, zinc and sodium salt of arsenic and antimony appeared. Water leaching could remove arsenic, and acid leaching residue obtained was then leached with acid. The leaching rate of indium was higher 6.98% compared with alkali roasting of copper dross-acid leaching. It showed that removing arsenic by water leaching and acid leaching could increase the leaching rate of indium and be beneficial to reducing subsequent acid consumption of extracting indium by acid leaching. The roasting temperature had a significant effect on the leaching rate of indium, and leaching rate of indium increased with the rise of roasting temperature. When roasting temperature ranged from 450°C to 600°C, leaching rate of indium increased significantly with the rise of roasting temperature. When roasting temperature rose from 450°C to 600°C, leaching rate of indium increased by 60.29%. The amount of sodium hydroxide had an significant effect on the leaching rate of indium, and the leaching of indium increased with the increase of the amount of sodium hydroxide, and the leaching rate of indium was obviously higher than that of copper dross blank roasting and acid leaching.

  11. Studies on Leaching of Oxidized Copper Ore from South America

    Science.gov (United States)

    Zhu, Deqing; Wu, Tengjiao; Guo, Zhenqi; Pan, Jian; Li, Ziyun

    A leaching study was conducted on South America oxidized copper ore assaying 3.10% Cu, and the process parameters were optimized, including leaching temperature, leaching time, acid consumption, liquid-solid ratio and stirring rate. The results show that copper leaching rate of 92.02% were achieved under the optimized conditions as follows: raw ore crushed to 100% passing 1mm, leaching by sulfuric acid at 70°C for 1.5h with a sulfuric acid consumption of 150kg/t, liquid-solid ratio of 2:1, stirring rate of 300r/min. The leaching solution is a good feed for the subsequent extraction-electrowinning processes due to its high copper concentration and low contents of impurities like calcium and iron ions.

  12. Assessment of Leaching of some Heavy Metals from Domestic ...

    African Journals Online (AJOL)

    The aim of this study is to assess the possible leaching of heavy metals from ceramic wares into different solutions. Ceramic spoon, pot, soup bowl, plate, mug and cup were leached in batch process using hot water and 4 % solutions of glacial acetic acid, HCl acid, NaOH and Na2CO3 respectively. Chromium, manganese ...

  13. Process for the separation and recovery of palladium and platinum from spent automobile catalyst leach liquor using LIX 84I and Alamine 336.

    Science.gov (United States)

    Reddy, B Ramachandra; Raju, B; Lee, Jin Young; Park, Hyung Kyu

    2010-08-15

    Spent catalysts from automobile industry contain environmentally critical and economically valuable metals such as Pt, Pd, Fe, Ni, Mn, and Cr. In this paper, we present a process for the selective separation and complete recovery of palladium (Pd) and platinum (Pt) from hydrochloric acid leach liquors of spent automobile catalyst employing solvent extraction method. Typical composition of leach liquor used for the present study contains (mg/L): Pd-150, Pt-550, Mn-500, Ni-1000, Fe-1500, Cr-100 and 3 M HCl. Selective separation of Pd from the leach liquor is achieved with 0.5 vol.% LIX 84I (2-hydroxy-5-nonylacetophenone oxime in a mixture with a high flash point hydrocarbon diluent) in kerosene at an aqueous to organic (A/O) ratio of 3 in 2 stages, with an enrichment factor of three. Quantitative stripping of Pd from loaded organic is achieved with 0.5 M thiourea and 1 M HCl. Co-extraction of Fe and Pt with 5 vol.% Alamine 336 (tertiary amine of mixed tri-octyl/decyl amine) in kerosene followed by selective scrubbing of Fe with dilute HCl and complete stripping of Pt from loaded organic was proposed with 0.5 M thiourea and 0.1 M HCl. Purity of Pd and Pt strip solutions are 99.7%. Finally, the present process can solve environmental related issues and at the same time recover valuable metals in pure form. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Recovery of tungsten from wolframite from the Igarape Manteiga mine (Rondonia - Brazil) via acidic leaching; Isolamento do tungstenio da volframita da mina de Igarape Manteiga (Rondonia - Brasil) por lixiviacao acida

    Energy Technology Data Exchange (ETDEWEB)

    Paulino, Jessica Frontino; Afonso, Julio Carlos [Departamento de Quimica Analitica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, RJ (Brazil); Mantovano, Jose Luiz; Vianna, Claudio Augusto; Cunha, Jose Waldemar Silva Dias da [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro - RJ (Brazil)

    2012-07-01

    We report results of the efficiency of tungsten extraction from wolframite concentrate (containing 61.5 wt % WO{sub 3}) from the Igarape Manteiga mine (state of Rondonia, Brazil) through acid leaching with strong mineral acids at 100 deg C and 400 rpm for 2-4 h. HCl yielded insoluble matter containing the highest WO{sub 3} content (90 wt %). This solid was dissolved in concentrated NH{sub 3(aq)} at 25 deg C and the insoluble matter filtrated. The filtrate was slowly evaporated. 70 wt % of the tungsten present in the starting concentrate material was recovered as ammonium paratungstate (APT). (author)

  15. Leaching of Uranium and Vanadium from Korean Domestic Ore

    Science.gov (United States)

    Kim, Joon Soo; Chung, Kyeong Woo; Lee, Hoo In; Lee, Jin-Young; Kumar, J. Rajesh

    Countries like Korea having very limited uranium resources and founded deposits having low grade metal values. Uranium is the main source to generate the nuclear power as cheap and more quantity of the electricity will generate. For this reasons the upcoming researchers in developed/developing countries are establishing more research and development on extraction and separation technologies for uranium. The present scientific study focused on leaching process of Korean domestic ore. The following experiments are carryout for optimization of the leaching process. Acid influence on leaching process was tested and noted that 2.0 M sulfuric acid concentration is the optimized conditions for present study. The time influence on leaching process was observed and its optimized 2 h for complete leaching process. The temperature influence tested and optimized the 80°C for complete leaching process and pulp density is 50% (wt %).

  16. [Leaching of uranium containing phosphorites with heterotrophic microorganisms].

    Science.gov (United States)

    Kullmann, K H; Schwartz, W

    1982-01-01

    The problem of heterotrophic leaching of metals was tested with uranium-containing phosphorites under laboratory conditions with regard to possible technical applications. As leaching agents we used the acids of citric and lactic acid fermentation, carried out with a strain of Aspergillus niger in sulfite liquor under different conditions and with lactic acid bacteria in wheye. Up to 12% uranium were soluted with citric acid fermentation of Marocco phosphorite containing 153 ppm U in Aspergillus niger cultures within 27 days.

  17. Mineralogy and uranium leaching of ores from Triassic Peribaltic sandstones.

    Science.gov (United States)

    Gajda, Dorota; Kiegiel, Katarzyna; Zakrzewska-Koltuniewicz, Grazyna; Chajduk, Ewelina; Bartosiewicz, Iwona; Wolkowicz, Stanislaw

    The recovery of uranium and other valuable metals from Polish Peribaltic sandstones were examined. The solid-liquid extraction is the first stage of the technology of uranium production and it is crucial for the next stages of processing. In the laboratory experiments uranium was leached with efficiencies 71-100 % by acidic lixiviants. Satisfactory results were obtained for the alkaline leaching process. Almost 100 % of uranium was leached with alkaline carbonate solution. In post leaching solutions only uranium and small amounts of vanadium were present.

  18. The effectiveness of surface liming in ameliorating the phytotoxic effects of soil contaminated by copper acid leach pad solution in an arid ecosystem

    Science.gov (United States)

    Golos, Peter

    2016-04-01

    Revegetation of sites following soil contamination can be challenging especially in identifying the most effective method for ameliorating phytotoxic effects in arid ecosystems. This study at a copper mine in the Great Sandy Desert of Western Australia investigated vegetation restoration of a site contaminated by acid (H2SO4) leach pad solution. Elevated soil copper at low soil pH is phytotoxic to plant roots inhibiting root elongation. In arid ecosystems where rapid root growth is crucial for seedling survival post germination physical or chemical barriers to root growth need to be identified and ameliorated. Initial attempt at rehabilitation of contaminated site with hydrated lime (CaOH2) at 2 tonnes/ha followed by ripping to 30 cm depth then seeding was ineffective as successful seedling emergence was followed by over 90% seedling mortality which was 10-fold greater than seedling mortality in an uncontaminated reference site. High mortality was attributed to seedling roots being impededed as soil water was more than 3-fold greater at 5 to 40 cm depth in contaminated site than reference site. In response to high seedling mortality after emergence test pits were dug to 1 m deep to collect soil samples at 10 cm intervals for phytotoxicity testing and to measure soil pH-CaCl2, copper (DPTA ion extraction), electrical conductivity and gravimetric water content in three replicate pits at three replicate sites. Also, soil impedance was measured down the soil profile at 5 cm intervals at six replicate points/pit. For phytotoxicity testing soil samples were placed into three replicate plastic pots/sample and seeded with 10 seeds of Avena sativa and watered daily. Seedlings were harvested after at least two weeks after seedling emergence and rooting depth in pots measured. There was no difference in seedling emergence and survival of seedlings between contaminated and uncontaminated soil samples however mean seedling root growth was significantly lower in soil samples

  19. Effect of Acid Dissolution Conditions on Recovery of Valuable Metals from Used Plasma Display Panel Scrap

    Directory of Open Access Journals (Sweden)

    Kim Chan-Mi

    2017-06-01

    Full Text Available The objective of this particular study was to recover valuable metals from waste plasma display panels using high energy ball milling with subsequent acid dissolution. Dissolution of milled (PDP powder was studied in HCl, HNO3, and H2SO4 acidic solutions. The effects of dissolution acid, temperature, time, and PDP scrap powder to acid ratio on the leaching process were investigated and the most favorable conditions were found: (1 valuable metals (In, Ag, Mg were recovered from PDP powder in a mixture of concentrated hydrochloric acid (HCl:H2O = 50:50; (2 the optimal dissolution temperature and time for the valuable metals were found to be 60°C and 30 min, respectively; (3 the ideal PDP scrap powder to acid solution ratio was found to be 1:10. The proposed method was applied to the recovery of magnesium, silver, and indium with satisfactory results.

  20. Photocatalytic properties of Co{sub 3}O{sub 4}/LiCoO{sub 2} recycled from spent lithium-ion batteries using citric acid as leaching agent

    Energy Technology Data Exchange (ETDEWEB)

    Santana, I.L.; Moreira, T.F.M.; Lelis, M.F.F.; Freitas, M.B.J.G., E-mail: marcosbjg@gmail.com

    2017-04-01

    In this work, cobalt and lithium from the cathodes of spent lithium-ion batteries were recycled to synthesize a mixture of Co{sub 3}O{sub 4} and LiCoO{sub 2}. The positive electrode was leached with citric acid in the green recycling. After being heated to 85 °C, the leaching solution formed a pink sol, and after being dried at 120 °C for 24 h, it formed a gel, which is a precursor material for Co{sub 3}O{sub 4} and LiCoO{sub 2} synthesis. A mixture of Co{sub 3}O{sub 4} and LT-LiCoO{sub 2} was obtained after the calcination of the precursor material at 450 °C for 3 h. The photocatalytic properties of the Co{sub 3}O{sub 4} and LiCoO{sub 2} were tested in the discoloration of methylene blue dye. The discoloration efficiency of methylene blue dye in the presence of Co{sub 3}O{sub 4} and LiCoO{sub 2} was 90% after 10 h and 100% after 24 h of heterogeneous catalysis. The contribution of this work is that it presents a means to produce valuable materials with photocatalytic properties from recycled batteries through a spent Li-ion battery recycling process without polluting the environment. - Highlights: • Synthesis a mixture of Co{sub 3}O{sub 4}/LiCoO{sub 2} from spent Li-ion batteries. • Citric acid for leaching of the cathodes of the spent Li-ion batteries. • Co{sub 3}O{sub 4}/LiCoO{sub 2} as catalysts in the photodegradation of the methylene blue dye.

  1. Study of the relation between hydrated portland cement composition and leaching resistance

    NARCIS (Netherlands)

    van Eijk, R.J.; Brouwers, Jos

    1998-01-01

    The present paper addresses cement compositions that have an optimal resistance against acid attack and hence, low leaching rates and optimal waste containment. To this end a shrinking core leaching model is used that describes the leaching of metals from a cement sample. This process is directly

  2. Geothermal energy for copper dump leaching

    Energy Technology Data Exchange (ETDEWEB)

    White, D.H.; Goldstone, L.A.

    1982-08-01

    This report evaluates the possibility of using geothermal energy to heat a sulfuric acid leaching solution for the purpose of faster and more efficient copper recovery from copper-containing minerals. Experimental studies reported in the literature have shown that this technique can be economically feasible for the extraction of copper from low-grade dump ores. Its main advantage appears to be the considerable reduction in long-term leaching periods; it could also be less expensive than other conventional processing operations if an economical geothermal resource were provided. However, this process has some pitfalls which might restrict the extent of geothermal energy use. Nevertheless, the process is still technologically sound, especially if groundwaters are used directly in the leaching operation.

  3. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    Science.gov (United States)

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Influence of Mechanical Activation on the selectivity of Bornite Leaching

    Directory of Open Access Journals (Sweden)

    Peter Baláž

    2004-12-01

    Full Text Available Sulfidic mineral bornit Cu5FeS4 was exposed to the selective leaching of copper in H2SO4 solution. Surface changes of the mechanically activated sulphide were investigated before and after leaching using the infrared spectroscopy and the scanning electron microscopy. The mechanical activation of the mineral resulted in the mechanochemical surface oxidation and in the formation of the carbonates and sulphates. Furthermore, the specific area and the disordering of the mineral crystal structure increased. These aspects influence the kinetic and selectivity of acid leaching of bornite.Acid leaching of mechanically activated bornite follows through the two stages. In the first, rapid stage of leaching, the simple dissolution of products occurs (iron carbonate, copper and iron sulphate, which are situated in the surface layer of mechanically activated bornite. A relatively high iron recovery is due to the dissolution of hematite which is a minor component of bornite. The second, slow stage of leaching represents leaching of minerals. Iron do not practically underlies to the leaching and the recovery of copper increases gradually.The leaching selectivity of bornite is defined by the ratio Cu/Fe and increases with the growing time of mechanical activation, but only to 10 minutes. Subsequently, an additional increase of the time of mechanical activation tends to decrease the selectivity what is probably caused by the effect of the reduction of reaction surface processes due to agglomeration effects pending the milling and the formation of sulphur on the surfaces of particles which restricted the access of reagents to the remaining mineral. Moreover, this fact was observed by the SEM analysis of bornite. The interdependence between the leaching selectivity of bornite and specific surface area indicates a direct effect of the surface deformation of mechanically activated bornite on the selectivity of leaching.

  5. Leaching of Light Rare Earth Elements from Sichuan Bastnaesite: A Facile Process to Leach Trivalent Rare Earth Elements Selectively from Tetravalent Cerium

    Science.gov (United States)

    Shen, Yueyue; Jiang, Ying; Qiu, Xianying; Zhao, Shilin

    2017-10-01

    The effects of the nitric acid concentration, leaching time, leaching temperature, and solid-to-liquid ratio on leaching efficiency were examined. From those results, a facile process for the selective leaching of trivalent rare earth elements (RE(III)) from tetravalent cerium (Ce(IV)) was proposed. The roasted bastnaesite was used to leach 34.87% of RE(III) and 2.15% of Ce(IV) at 60°C for 0.5 h with an acid concentration of 0.5 mol/L. This selective leaching process can be described by the shrinking-core model that follows the kinetic model 1 - 2/3 α - (1 - α)2/3. Subsequently, the leached slag was hydrothermally treated and followed by thorough leaching with 4.0-mol/L nitric acid. Furthermore, the specific surface area of the final leached slag is 57.7 m2/g, which is approximately 650 times higher than that of raw ore. Finally, selective leaching of RE(III) (>90%) was achieved without using an organic solvent for extraction, whereas lower value Ce(IV)was presented in the leached slag (>92%).

  6. Ligand Selection Model for Leaching of Low Grade Zinc Oxide Ores

    Science.gov (United States)

    Yang, Tianzu; Rao, Shuai; Zhang, Duchao; Chen, Lin; Liu, Weifeng

    A new ligand selection model is proposed for leaching of low grade zinc oxide ores. The model demonstrates that the formation constant between ligand and zinc ions plays a significant role in the leaching process. A series of leaching experiments with different ligand concentration are conducted to assess the selection model. The results show that when nitrilotriacetic acid is used as the leaching agent, the highest zinc extraction is obtained. The zinc leaching rate is 84.33% in the presence of 0.4 mol/L nitrilotriacetic acid and liquid-solid ratio of 10 mL/g.

  7. Impact of wheat straw biochar addition to soil on the sorption, leaching, dissipation of the herbicide (4-chloro-2-methylphenoxy)acetic acid and the growth of sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Tatarková, Veronika; Hiller, Edgar; Vaculík, Marek

    2013-06-01

    Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

    Science.gov (United States)

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2014-05-01

    Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

  9. Phase Engineering of Perovskite Materials for High-Efficiency Solar Cells: Rapid Conversion of CH3NH3PbI3to Phase-Pure CH3NH3PbCl3via Hydrochloric Acid Vapor Annealing Post-Treatment.

    Science.gov (United States)

    Zhou, Weiran; Zhou, Pengcheng; Lei, Xunyong; Fang, Zhimin; Zhang, Mengmeng; Liu, Qing; Chen, Tao; Zeng, Hualing; Ding, Liming; Zhu, Jun; Dai, Songyuan; Yang, Shangfeng

    2018-01-17

    Organometal halide CH 3 NH 3 PbI 3 (MAPbI 3 ) has been commonly used as the light absorber layer of perovskite solar cells (PSCs), and, especially, another halide element chlorine (Cl) has been often incorporated to assist the crystallization of perovskite film. However, in most cases, a predominant MAPbI 3 phase with trace of Cl - is obtained ultimately and the role of Cl involvement remains unclear. Herein, we develop a low-cost and facile method, named hydrochloric acid vapor annealing (HAVA) post-treatment, and realize a rapid conversion of MAPbI 3 to phase-pure MAPbCl 3 , demonstrating a new concept of phase engineering of perovskite materials toward efficiency enhancement of PSCs for the first time. The average grain size of perovskite film after HAVA post-treatment increases remarkably through an Ostwald ripening process, leading to a denser and smoother perovskite film with reduced trap states and enhanced crystallinity. More importantly, the generation of MAPbCl 3 secondary phase via phase engineering is beneficial for improving the carrier mobility with a more balanced carrier transport rate and enlarging the band gap of perovskite film along with optimized energy level alignment. As a result, under the optimized HAVA post-treatment time (2 min), we achieved a significant enhancement of the power conversion efficiency (PCE) of the MAPbI 3 -based planar heterojunction-PSC device from 14.02 to 17.40% (the highest PCE reaches 18.45%) with greatly suppressed hysteresis of the current-voltage response.

  10. Innovative leaching of cobalt and lithium from spent lithium-ion batteries and simultaneous dechlorination of polyvinyl chloride in subcritical water.

    Science.gov (United States)

    Liu, Kang; Zhang, Fu-Shen

    2016-10-05

    In this work, an effective and environmentally friendly process for the recovery of cobalt (Co) and lithium (Li) from spent lithium-ion batteries (LIBs) and simultaneously detoxification of polyvinyl chloride (PVC) in subcritical water was developed. Lithium cobalt oxide (LiCoO2) power from spent LIBs and PVC were co-treated by subcritical water oxidation, in which PVC served as a hydrochloric acid source to promote metal leaching. The dechlorination of PVC and metal leaching was achieved simultaneously under subcritical water oxidation. More than 95% Co and nearly 98% Li were recovered under the optimum conditions: temperature 350°C, PVC/LiCoO2 ratio 3:1, time 30min, and a solid/liquid ratio 16:1 (g/L), respectively. Moreover, PVC was completely dechlorinated at temperatures above 350°C without any release of toxic chlorinated organic compounds. Assessment on economical and environmental impacts revealed that the PVC and LiCoO2 subcritical co-treatment process had significant technical, economic and environmental benefits over the traditional hydrometallurgy and pyrometallurgy processes. This innovative co-treatment process is efficient, environmentally friendly and adequate for Co and Li recovery from spent LIBs and simultaneous dechlorination of PVC in subcritical water. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

    Directory of Open Access Journals (Sweden)

    mehdi amini

    2013-12-01

    Full Text Available In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solution and copper oxide ore is exothermal and the pregnant leach solution (PLS, which is drained off the leaching heap, has a higher temperature than the dripped acidic solution. The PLS temperature variations cause some changes in the viscosity and density which affect the gravelly drainage layer's permeability. In this research, a special permeability measuring system was devised for determining the effects of the PLS temperature variations on the permeability coefficient of the gravelly drainage layer of heap leaching structures. The system, consisting of a thermal acid resistant element and a thermocouple, controls the PLS temperature, which helps measure the permeability coefficient of the gravelly drainage layer. The PLS and gravelly drainage layer of Sarcheshmeh copper mine heap leaching structure No. 1 were used in this study. The permeability coefficient of the gravelly soil was measured against the PLS and pure water at temperatures varying between 3°C to 60°C. Also, the viscosity and density of the PLS and pure water were measured at these temperatures and, using existing theoretical relations, the permeability coefficient of the gravel was computed. A comparison between the experimental and theoretical results revealed a good conformity between the two sets of results. Finally, a case (Taft heap leaching structure, Yazd, Iran was studied and its gravelly drainage layer was designed based on the results of the present research.

  12. Dissolution kinetics of pyrite ore by hydrochloric acid | Baba ...

    African Journals Online (AJOL)

    The effects of HCl concentration, tem-perature and particle size on the dissolution rate indicated that about 76.4 % of the ore of < 0.1 mm particle size was dissolved at 80 ¢ªC and stirring rate of 360 rpm. The dissolution rate was also dependence on hydrogen ion concentration of the reaction system. Activation energy of ...

  13. Hydrochloric Acid and the Chlorine Budget of the Lower Stratosphere

    Science.gov (United States)

    Webster, C.; May, R.; Jaegle, L.; Hu, H.; Sander, S.; Gunson, M.; Toon, G.; Russell, J., III; Stimpfle, R.; Koplow, J.; hide

    1994-01-01

    Concentrations of hc1 measured in the lower stratosphere in 1993 by the ALIAS instrument on the ER-2 aircraft reveal that only 40% of inorganic chlorine (CL sub y, inferred from in situ measurements of organic chlorinated source gases) is present as HC1, significantly lower than model predictions.

  14. A mechanism for hydrochloric acid production in cloud

    Science.gov (United States)

    Glenn K. Yue; Volkar A. Mohnen; C. S. Kiang

    1976-01-01

    A theoretical model describing the general interaction between atmospheric trace gases, such as SO2, NH3, CO2 and O2, chemical reactant gaseous product H2SO4 and hydrometeors containing NaCl is proposed to study a possible mechanism...

  15. Hydrochloric acid and the chlorine budget of the lower statosphere

    Science.gov (United States)

    Webster, C. R.; May, R. D.; Jaegle, L.; Hu, H.; Sander, S. P.; Gunson, M. R.; Toon, G. C.; Russell, J. M., III; Stimpfle, R. M.; Koplow, J. P.

    1994-01-01

    Concentrations of HCl measurements in the lower stratosphere in 1993 by the ALIAS instrument on the ER-2 aircraft reveal that only 40% of inorganic chlorine (Cl(y), inferred from in situ measurements of organic chlorinated sources gases) is present as HCl, significantly lower than model predictions. Although the sum of measured HCl, ClO and ClONO2, the latter inferred from measurements of ClO and NO2 equals Cl(y) to within the incertainty of measurement, it is systematically less than Cl(y) by 30-50%. This discrepancy suggests that concentrations of ClONO2 may exceed those of HC; near 20 km altitude, consistent with a slower photolysis rate for ClONO2 than calculated using recommended cross sections. Comparison of profiles of HCl measured during 1992 and 1193 at mid-latitudes by balloon (BLISS and MARKIV), space shuttle (ATMOS), and satellite (HALOE) instruments with the aircraft data reveal an apparent pressure dependence to the HCl to Cl(y) ratio, consistent with a factor of 3-10 reduction in the photolysis rate for ClONO2 at ER-2 altitudes. However, the diurnal variation of ClO is well-simulated by models using the recommended photolysis rate, and simulations measurements of ClONO2 and HCl at mid-latitudes by ATMOS and MARKIV report HCl (HCL+ ClONO2) ratios greater than or equal to 50%. Premliminary measurements by ALIAS in the southern hemisphere report HCl/Cl(y) values of about 75%.

  16. Effect of Hydrochloric Acid, Mechanical Scarification, Wet Heat ...

    African Journals Online (AJOL)

    Michael Horsfall

    HCL), Wet heat. ABSTRACT; The effect of different ... treatments observed showed 100% for wet heat, 90% for scarification (sand paper) and 70% for HCL of 50% ... the principle constant being a dry season of 5-7 month/year. It may grow in ...

  17. The effect of sulphide minerals on uranium oxidation state in in-situ leaching

    Science.gov (United States)

    Pastukhov, A. M.; Skripchenko, S. Yu.

    2017-09-01

    The thermodynamic model of uranium in-situ leaching process at the stages of acidification and active leaching were investigated. It was demonstrated that in the frontal zone of acid leaching solutions reduction of uranium(VI) up to uranium(IV) was possible due to the nature of redox processes involving hydrogen sulfide. At the same time uranium was precipitated as U(OH)4. In order to eliminate the negative influence of sulfide minerals and hydrogen sulfide, artificial oxidizers were proposed to be used at the both stages of in-situ leaching process, i.e. active leaching and acidification of new process cells.

  18. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.

    2011-01-01

    The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled with geoche......The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled...

  19. Leaching Test Relationships, Laboratory-to-Field Comparisons and Recommendations for Leaching Evaluation using the Leaching Environmental Assessment Framework (LEAF)

    Science.gov (United States)

    This report presents examples of the relationships between the results of laboratory leaching tests, as defined by the Leaching Environmental Assessment Framework (LEAF) or analogous international test methods, and leaching of constituents from a broad range of materials under di...

  20. A mathematical model for isothermal heap and column leaching

    Directory of Open Access Journals (Sweden)

    Lima L.R.P. de Andrade

    2004-01-01

    Full Text Available Leaching occurs in metals recovery, in contaminated soil washing, and in many natural processes, such as fertilizer dissolution and rock weathering. This paper presents a model developed to simulate the transient evolution of the dissolved chemical species in the heap and column isothermal leaching processes. In this model, the solid bed is numerically divided into plane layers; the recovery of the chemical species, the enrichment of the pregnant leach solution, and the residual concentration of the leaching agent are calculated by interactions among the layers. The solution flow in the solid bed is assumed as unidirectional without dispersion, and the solid-fluid reaction is described by a diffusive control model that is integrated analytically for each time step. The data set used in the model include physical-chemical, geometrical, and operational variables, such as: leachable chemical species content, leaching agent flow rate and concentration, particles size distribution, solution residence time in the solid bed, and solid bed length, weight and irrigated area. The results for two case studies, namely, an industrial gold heap leaching and a pilot column copper acid leaching, showed that the model successful predict the general features of the process time evolution.

  1. Sulfur dioxide leaching of spent zinc-carbon-battery scrap

    Science.gov (United States)

    Avraamides, J.; Senanayake, G.; Clegg, R.

    Zinc-carbon batteries, which contain around 20% zinc, 35% manganese oxides and 10% steel, are currently disposed after use as land fill or reprocessed to recover metals or oxides. Crushed material is subjected to magnetic separation followed by hydrometallurgical treatment of the non-magnetic material to recover zinc metal and manganese oxides. The leaching with 2 M sulfuric acid in the presence of hydrogen peroxide recovers 93% Zn and 82% Mn at 25 °C. Alkaline leaching with 6 M NaOH recovers 80% zinc. The present study shows that over 90% zinc and manganese can be leached in 20-30 min at 30 °C using 0.1-1.0 M sulfuric acid in the presence of sulfur dioxide. The iron extraction is sensitive to both acid concentration and sulfur dioxide flow rate. The effect of reagent concentration and particle size on the extraction of zinc, manganese and iron are reported. It is shown that the iron and manganese leaching follow a shrinking core kinetic model due to the formation of insoluble metal salts/oxides on the solid surface. This is supported by (i) the decrease in iron and manganese extraction from synthetic Fe(III)-Mn(IV)-Zn(II) oxide mixtures with increase in acid concentration from 1 M to 2 M, and (ii) the low iron dissolution and re-precipitation of dissolved manganese and zinc during prolonged leaching of battery scrap with low sulfur dioxide.

  2. Use of dolomite phosphate rock (DPR) fertilizers to reduce phosphorus leaching from sandy soil.

    Science.gov (United States)

    Chen, G C; He, Z L; Stoffella, P J; Yang, X E; Yu, S; Calvert, D

    2006-01-01

    There is increasing concern over P leaching from sandy soils applied with water-soluble P fertilizers. Laboratory column leaching experiments were conducted to evaluate P leaching from a typical acidic sandy soil in Florida amended with DPR fertilizers developed from dolomite phosphate rock (DPR) and N-Viro soil. Ten leaching events were carried out at an interval of 7 days, with a total leaching volume of 1,183 mm equivalent to the mean annual rainfall of this region during the period of 2001-2003. Leachates were collected and analyzed for total P and inorganic P. Phosphorus in the leachate was dominantly reactive, accounting for 67.7-99.9% of total P leached. Phosphorus leaching loss mainly occurred in the first three leaching events, accounting for 62.0-98.8% of the total P leached over the whole period. The percentage of P leached (in the total P added) from the soil amended with water-soluble P fertilizer was higher than those receiving the DPR fertilizers. The former was up to 96.6%, whereas the latter ranged from 0.3% to 3.8%. These results indicate that the use of N-Viro-based DPR fertilizers can reduce P leaching from sandy soils.

  3. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk [Department of Energy & Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Kim, Sookyung [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Yang, Donghyo, E-mail: ydh@kigam.re.kr [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Kwon, Kyungjung, E-mail: kfromberk@gmail.com [Department of Energy & Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of)

    2016-08-05

    Highlights: • Ammoniacal leaching is used to recover spent Li-ion battery cathode materials. • Leaching agents consist of ammonia, ammonium sulfite and ammonium carbonate. • Ammonium sulfite is a reductant and ammonium carbonate acts as pH buffer. • Co and Cu can be fully leached while Mn and Al are not leached. • Co recovery via ammoniacal leaching is economical compared to acid leaching. - Abstract: As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn{sub 2}O{sub 4}, LiCo{sub x}Mn{sub y}Ni{sub z}O{sub 2,} Al{sub 2}O{sub 3} and C while the leach residue is composed of LiNi{sub x}Mn{sub y}Co{sub z}O{sub 2}, LiMn{sub 2}O{sub 4}, Al{sub 2}O{sub 3}, MnCO{sub 3} and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al.

  4. Method of operating a heap leach for recovering uranium and vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, S.; Skiles, D.O.; Hansen, D.J.

    1987-10-20

    A method is described of operating a heap leach for leaching uranium and vanadium from a uranium-vanadium bearing ore formed into a relatively tall heap from a mixture of coarsely crushed ore and concentrated sulfuric acid. It consists of leaching the heap in sections in multiple cycles in accordance with a leaching operation comprising the steps o: (a) applying a dilute solution of between 1 to 5% sulfuric acid to the first section at a predetermined average flow rate over a predetermined time; (b) directing the leach liquor output into a product liquor sump for direct delivery to a processing plant for extracting uranium values; (c) applying a stronger acid solution of between 10 to 20% H/sub 2/SO/sub 4/ to the first section upon completion of step (a); (d) directing the leach liquor output into a high grade recycle pond; (e) recycling the leach liquor through the first section a predetermined multiple number of times; (f) directing the output leach liquor into the product liquor sump for direct delivery to the processing plant; (g) applying a fresh dilute acid solution as defined in step (a) to each section in a timed sequence upon substantial completion of the dilute acid application to the preceding section; (h) directing the leach liquor output of each section from step (g) to the product liquor jumps; (i) applying acid solution to each section in succession following the completion of step (g) in each corresponding section respectively; (j) directing the output leach liquor (i) into the high grade recycle pond; and (k) recycling the leach liquor (j) through each section a predetermined multiple number of times with the last cycle passed through the next section in succession before being sent to the product liquor sump in accordance with step (f).

  5. Analytical results for total-digestions, EPA-1312 leach, and net acid production for twenty-three abandoned metal-mining related wastes in the Boulder River watershed, northern Jefferson County, Montana

    Science.gov (United States)

    Fey, David L.; Desborough, George A.; Finney, Christopher J.

    2000-01-01

    IntroductionMetal-mining related wastes in the Boulder River basin study area in northern Jefferson County, Montana, have been implicated in their detrimental effects on water quality with regard to acid generation and toxic-metal solubilization during snow melt and storm water runoff events. This degradation of water quality is defined chiefly by the “Class 1 Aquatic Life Standards” that give limits for certain dissolved metal concentrations according to water alkalinity.Veins enriched in base- and precious metals were explored and mined in the Basin, Cataract Creek, and High Ore Creek drainages over a period of more than 70 years. Extracted minerals included galena, sphalerite, pyrite, chalcopyrite, tetrahedrite and arsenopyrite. Most of the metal-mining wastes in the study area were identified and described by the Montana Bureau of Mines and Geology. In 1997, the U.S. Geological Survey collected 20 composite samples of mine-dump or tailings waste from ten sites in the Basin and Cataract Creek drainages, and two samples from one site in the High Ore Creek drainage. Desborough and Fey presented data concerning acid generation potential, mineralogy, concentrations of certain metals by energy-dispersive X-ray fluorescence (EDXRF), and trace-element leachability of mine and exploration wastes from the ten sites of the Basin and Cataract Creek drainages. The present report presents total-digestion major- and trace-element analyses, net acid production (NAP), and results from the EPA-1312 synthetic precipitation leach procedure (SPLP) performed on the same composite samples from the ten sites from the Basin and Cataract Creek drainages, and two composite samples from the site in the High Ore Creek drainage.

  6. LEACH-A: An Adaptive Method for Improving LEACH Protocol

    Directory of Open Access Journals (Sweden)

    Jianli ZHAO

    2014-01-01

    Full Text Available Energy has become one of the most important constraints on wireless sensor networks. Hence, many researchers in this field focus on how to design a routing protocol to prolong the lifetime of the network. The classical hierarchical protocols such as LEACH and LEACH-C have better performance in saving the energy consumption. However, the choosing strategy only based on the largest residue energy or shortest distance will still consume more energy. In this paper an adaptive routing protocol named “LEACH-A” which has an energy threshold E0 is proposed. If there are cluster nodes whose residual energy are greater than E0, the node of largest residual energy is selected to communicated with the base station; When all the cluster nodes energy are less than E0, the node nearest to the base station is select to communication with the base station. Simulations show that our improved protocol LEACH-A performs better than the LEACH and the LEACH-C.

  7. Recovery of valuable metals from spent lithium-ion batteries by ultrasonic-assisted leaching process

    Science.gov (United States)

    Li, Li; Zhai, Longyu; Zhang, Xiaoxiao; Lu, Jun; Chen, Renjie; Wu, Feng; Amine, Khalil

    2014-09-01

    The anticipated significant use of lithium-ion batteries (LIBs) for energy storage applications in electric grid modernization and vehicle electrification shall generate a large quantity of solid waste that could become potential environmental hazards and waste natural resources. Recycling of the major components from spent LIBs is, therefore, considered desirable to prevent environmental pollution and to recycle valuable metals. This study reports on the application of ultrasonic-assisted technology to the leaching of cobalt and lithium from the cathode active materials of spent LIBs. Three acids were tested for the leaching process: two inorganic acids (H2SO4 and HCl) and one organic acid (citric acid, C6H8O7·H2O). The results show that the leaching of Co and Li is more efficient with citric acid than with the two inorganic acids. More than 96% Co and nearly 100% Li were recovered from spent LIBs. The optimal leaching conditions were 0.5 M citric acid with 0.55 M H2O2, a solid-to-liquid ratio of 25 g L-1, a temperature of 60 °C, leaching time of 5 h, and ultrasonic power of 90 W. The high leaching efficiency is mainly ascribed to the unique cavitation action of the ultrasonic waves. This ultrasonic-assisted leaching process with organic acid is not only effective but also environmentally friendly.

  8. Sequential Leaching of Chromium Contaminated Sediments - A Study Characterizing Natural Attenuation

    Science.gov (United States)

    Musa, D.; Ding, M.; Beroff, S.; Rearick, M.; Perkins, G.; WoldeGabriel, G. W.; Ware, D.; Harris, R.; Kluk, E.; Katzman, D.; Reimus, P. W.; Heikoop, J. M.

    2015-12-01

    Natural attenuation is an important process in slowing down the transport of hexavalent chromium, Cr(VI), an anthropogenic environmental contaminant, either by adsorption of Cr(VI) to sediments, or by reduction to nontoxic trivalent chromium, Cr(III). The capacity and mechanism of attenuation is explored in this sequential leaching study of different particle size fractions of chromium contaminated sediments and similar uncontaminated sediments from the regional aquifer near Los Alamos, New Mexico. Using this leaching protocol each sediment sample is split in two: one half is leached three times using a 0.1 M sodium bicarbonate/carbonate solution, while the second half is leached three times using a 0.01 M nitric acid, followed by two consecutively increasing magnitudes of nitric acid concentrations. Based on the amphoteric nature of chromium, alkaline leaching is used to establish the amount of Cr(VI) sorbed on the sediment, whereas acid leaching is used to establish the amount of Cr(III). The weak acid is predicted to release the attenuated anthropogenic Cr(III), without affecting Cr-bearing minerals. The sequential, stronger, acid is anticipated to leach Cr(III)-incorporated in the minerals. The efficiency and validation of the sequential leaching method is assessed by comparing the leaching behavior of bentonite and biotite samples, with and without loaded Cr(VI). A 97% chromium mass balance of leached Cr(VI)-loaded bentonite and biotite proves the viability of this method for further use on leaching contaminated sediments. By comparing contaminated and uncontaminated sediment leachate results, of chromium and other major and trace elements, the signature of anthropogenic chromium is determined. Further mineralogical characterization of the sediments provides a quantitative measure of the natural attenuation capacity for chromium. Understanding these results is pertinent in delineating the optimal procedure for the remediation of Cr(VI) in the regional aquifer

  9. [Dynamic leaching behavior of heavy metals in eco-cement mortar block].

    Science.gov (United States)

    Li, Cheng; Liu, Jian-Guo; Zhang, Jun-Li; Yue, Dong-Bei; Nie, Yong-Feng; Wang, Chang-Hai

    2008-03-01

    A dynamic leaching test with the renewal of acidic leaching medium was designed to study the leaching behavior of the seven heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) in three solidified eco-cement mortar samples with different particle size (fine granule, coarse granule, block) under a long-term leaching condition. It was demonstrated that all the heavy metals were detected in the leachate except Cd. The leaching ratio of Cr was the highest when compared with other metals in the same sample, and the leaching ratio of every metal showed an identical tendency: fine granule> coarse granule > block. The on-going leaching part of the relationship curve of accumulative leaching point (Pt) and t1/2 of each metal presented a fairly good linearity, which indicated that the leaching process was under the control of diffusion mechanism by the Fick Law. To each metal, the effective diffusion coefficient (Deff) showed a tendency of fine granule metals, the Deff was very low, with the magnitude around 10(-10) cm2/s, which meant the leaching process would take a relatively long time.

  10. Influence of several experimental parameters on As and Se leaching from coal fly ash samples

    Energy Technology Data Exchange (ETDEWEB)

    Otero-Rey, Jose R. [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Mato-Fernandez, Maria J. [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Moreda-Pineiro, Jorge [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Alonso-Rodriguez, Elia [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain)]. E-mail: elia@udc.es; Muniategui-Lorenzo, Soledad [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Lopez-Mahia, Purificacion [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Prada-Rodriguez, Dario [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain)

    2005-02-28

    Coal fly ash leaching process for As and Se is studied. Environmental parameters such as pH, temperature, solid-liquid ratio, particle size and leaching time are taken into account in order to simulate As and Se leaching process for disposal coal fly ash. Analysis of reference materials was carried out by using of hydride generation coupled to atomic fluorescence spectrometry. Plackett-Burman experimental design is used to know the significative parameters, and Box-Behnken experimental design is used to refine the results obtained for these significative parameters. pH and temperature shown a hardly influence in leaching process. Furthermore, leaching time was also significative. According our results, it may be assumed that percentage of As and Se leaching in experimental conditions tested is relatively low for acidic fly ashes.

  11. Effects of prone and supine position on oxygenation and inflammatory mediator in a hydrochloric acid-induced lung dysfunction in rats Efeitos da posição prona e supina na oxigenação e mediador inflamatório na disfunção pulmonar induzida por ácido clorídrico em ratos

    Directory of Open Access Journals (Sweden)

    Wagner Rogério Souza de Oliveira

    2008-10-01

    Full Text Available PURPOSE: To compare the effectiveness of mechanical ventilation of supine versus prone position in hydrochloric acid (HCl-induced lung dysfunction. METHODS: Twenty, adult, male, Wistar-EPM-1 rats were anesthetized and randomly grouped (n=5 animals per group as follows: CS-MV (mechanical ventilation in supine position; CP-MV (mechanical ventilation in prone position; bilateral instillation of HCl and mechanical ventilation in supine position (HCl+S; and bilateral instillation of HCl and mechanical ventilation in prone position (HCl+P. All groups were ventilated for 180 minutes. The blood partial pressures of oxygen and carbon dioxide were measured in the time points 0 (zero; 10 minutes before lung injury for stabilization, and at the end of times acid injury, 60, 120 and 180 minutes of mechanical ventilation. At the end of experiment the animals were euthanized, and bronchoalveolar lavages (BALs were taken to determine the contents of total proteins, inflammatory mediators, and lungs wet-to-dry ratios. RESULTS: In the HCl+P group the partial pressure of oxygen increased when compared with HCl+S (128.0±2.9 mmHg and 111.0±6.7 mmHg, respectively within 60 minutes. TNF-α levels in BAL do not differ significantly in the HCl+P group (516.0±5.9 pg/mL, and the HCl+S (513.0±10.6 pg/mL. CONCLUSION: The use of prone position improved oxygenation, but did not reduce TNF-α in BAL upon lung dysfunction induced by HCl.OBJETIVO: Comparar os efeitos da ventilação mecânica em posição prona versus supina na disfunção pulmonar induzida por ácido clorídrico (HCl. MÉTODOS: Vinte ratos, adultos, Wistar-EPM-1 foram anestesiados e distribuídos aleatoriamente em grupos (n=5 animais por grupo: CS-MV (controle, ventilado mecanicamente em posição supina; CP-MV (controle, ventilado mecanicamente em posição prona; instilação bilateral de HCl e ventilação mecânica em posição supina (HCl+S ou ventilação em posição prona (HCl+P. Todos os grupos

  12. Environmental Hazard Assessment of Jarosite Waste Using Batch Leaching Tests

    Directory of Open Access Journals (Sweden)

    M. Kerolli – Mustafa

    2018-01-01

    Full Text Available Jarosite waste samples from Trepça Zinc Industry in Kosovo were subjected to two batch leaching tests as an attempt to characterize the leaching behavior and mobility of minor and major elements of jarosite waste. To achieve this, deionized water and synthetic acidic rain leaching tests were employed. A two-step acidic treatment in microwave digestion system were used to dissolve jarosite waste samples, followed by determination of Al, Ag, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, P, Pb, S, Si, Sr, and Zn by inductively coupled plasma optical emission spectrometry (ICP-OES. The validation of the procedure was performed by the analysis of two geochemical reference materials, S JR-3 and S Jsy-1. Two toxicity leaching tests revealed a high metal releasing of Cd, Cu, Ni, Mn, Pb, Zn, and As, and the metal release risk for these elements is still very high due the low pH and acid rain. The statistical analysis showed useful data information on the relationship between elements in jarosite samples in two different extraction conditions (deionized water and synthetic acid rain.

  13. Investigation of Chemical and Microbial Leaching of Iron ore in ...

    African Journals Online (AJOL)

    MICHAEL

    ABSTRACT: Investigations on the chemical and microbial leaching of a Nigerian Iron-ore in sulphuric acid have been carried out. The influence of ... and Awaruite, formed by the association of nickel with iron. Other minerals of .... Characterization of the thiobaccilus bacteria:- The solidified nutrient agar was melted in a ...

  14. Effect of acid and alkaline hydrolysis on the concentrations of ...

    African Journals Online (AJOL)

    Thevetia peruviana seeds cake were defatted and then treated with varying concentrations each of hydrochloric acid, sodium hydroxide and calcium hydroxide solutions. Each product of hydrolysis was extracted with chloroform to isolate aglycones, the toxins of the seed. Various concentrations of hydrochloric acid and ...

  15. Imouraren - uranium leaching tests and specificities with analcites

    Energy Technology Data Exchange (ETDEWEB)

    Wattinne-Morice, A., E-mail: aurelia.wattinne@areva.com [AREVA - Tour Areva, Paris la Defense (France); Belieres, M. [AREVA - Service d' Etudes de Procede et Analyses (SEPA), Bessines sur Gartempe (France)

    2010-07-01

    Imouraren is a sedimentary uranium deposit (total > 150 000 tU, average U ~ 0.08 %), located in Niger (~ 100 km from Agadez). Uranium mineralization is trapped in sandstones and is widely oxidized (uranotyle, metatuyamunite), but a part remains reduced (pitchblende, uraninite). The sandstones have a peculiar mineralogical assemblage (analcite partly chloritized) which can affect uranium recovery. Several acid heap leaching tests have been completed to determine the most suitable process parameters. Microscopic studies and XRD analysis performed on fresh ore and on leached residue highlight the complex behavior of uranium and the associated mineralogical families during the tests. (author)

  16. Recovery of Precious and Base Metals from Waste Printed Circuit Boards Using a Sequential Leaching Procedure

    Science.gov (United States)

    Batnasan, Altansukh; Haga, Kazutoshi; Shibayama, Atsushi

    2018-02-01

    This paper considers the issue of recycling of waste printed circuit boards (WPCBs) containing precious and base metals in appreciable amounts. High-pressure oxidative leaching (HPOL) with dilute sulfuric acid resulted in removal of a significant amount of base metals from a WPCB ash sample obtained by incineration at 800°C. The parameters investigated in the precious metal leaching from WPCB residue after HPOL included the sulfuric acid concentration, thiourea concentration, oxidant concentration, leaching temperature, and leaching time. Recovery of gold, silver, and palladium of 100%, 81%, and 13% from the WPCB residue sample was achieved by thiourea leaching under optimized conditions. The results show that the efficiency of precious metal dissolution from the WPCB sample using thiourea solution depended strongly on the concentration of both thiourea and oxidant.

  17. Petrographical and mineralogical analysis of coal after biological leaching

    Directory of Open Access Journals (Sweden)

    Kupka Daniel

    2000-09-01

    Full Text Available For coal utilization the sulphur content is a decisive parameter for the quality of the coal. In many countries clean coal technologies have to be applied on the basis of regulations concerning fuel quality and emission standards for dust, CO, SO2 and NOx in the flue gas. It becomes quite obvious that it is always preferable to keep the sulphur levels in coal at a minimum. Bacterial oxidation of the sulphur present in coal could well be thought of as an effective alternative.Desulphurization by bacteria Thiobacillus ferrooxidans was applied to coal sample from Sokolov mine. Bacteria growing in batch culture on ferrous iron at initial pH 1.6 were harvested at the later growth phase. The ferric iron precipitates were separated from the cells by centrifugation and the rest medium by membrane filtration. Cell pellet captured on the filter was washed by hydrochloric acid and distilled water and finally suspended in fresh Waksmann & Joffe medium. The medium was previously acidified by 5M H2SO4 to pH 2. Initial concentration of sulphates in medium was 1.8 g L-1. Desulphurization of coal was studied in a stirred batch reactor at 10% w/v pulp density in diluted H2SO4 at pH = 2.The effect of bacterial leaching on mineral and organic matter of coal was followed by optical microscopy. Petrographic evaluation of the coal matter samples consisted of the determination of reflectance of gelified huminite macerals (R0, determination of maceral group contents of huminite, liptinite, inertinite and determination of the mineral content with emphasis on the various forms of iron sulphides. The sample examined were brown coal with higher liptinite and pyrite contents. The huminite reflectance of 0,33 % is corresponding to the lignitic metatype. Huminite concentration is 65,7 % and is the most abundant maceral group. The maceral ulminite and densinite contributes to the high huminite content. The concentration of attrinite, who be pass to liptodetrinite, textinite

  18. Static leaching of uraniferous shales on open areas; Lixiviacion estatica de izarras uraniferas (tratamiento de mineral rico en era abierta)

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Nieto, J.; Cordero, G.; Villarrubia, M.

    1973-07-01

    This report describes the tests on acid heap leaching with conventional (1.400 ppm U{sub 3}O{sub 8}) crushed uranium ores. We use open circuits with low internal recycled. Using starving acidity in the leaching solutions we obtain a smooth solubilization of uranium and, at the same time, the pregnant liquors are good for the solvent extraction recovery. (Author)

  19. Stability and leaching of cobalt smelter fly ash

    DEFF Research Database (Denmark)

    Vítková, Martina; Hyks, Jiri; Ettler, Vojtěch

    2013-01-01

    The leaching behaviour of fly ash from a Co smelter situated in the Zambian Copperbelt was studied as a function of pH (5–12) using the pH-static leaching test (CEN/TS 14997). Various experimental time intervals (48h and 168h) were evaluated. The leaching results were combined with the ORCHESTRA...... elements, the released concentrations were very similar after 48h and 168h, indicating near-equilibrium conditions in the system. Calcite, clinopyroxenes, quartz and amorphous phases predominated in the fly ash. Various metallic sulfides, alloys and the presence of Cu, Co and Zn in silicates and glass were...... and Cu. However, there is a high risk of Co, Cu, Pb and Zn mobility in the acidic soils around the smelter facility. Therefore, potential local options for “stabilisation” of the fly ash were evaluated on the basis of the modelling results using the PHREEQC code....

  20. Alkaline Leaching of Low Zinc Content Iron-Bearing Sludges

    Directory of Open Access Journals (Sweden)

    Gargul K.

    2016-03-01

    Full Text Available Various types of waste materials containing zinc (e.g. dusts and sludges from gas dedusting process are obtained in steel industry. The contents of Zn in these materials may vary considerably. Even a low concentration of zinc in recirculated products precludes their recycling in ferrous metallurgy aggregates. Long storage of this type of material can lead to contamination of soil and water by zinc compounds which can be leached out by acid rain, for example. This paper focuses on research involving alkaline leaching tests of low zinc content iron-bearing materials. These tests were preceded by the analysis of the elemental, phase and grain size composition, and analysis of the thermodynamic conditions of the leaching process. The main aim of research was to decrease the content of the zinc in the sludge to the level where it is suitable as an iron-bearing material for iron production (~1% Zn. Leaching at elevated temperatures (368 K, 60 min has led to a decrease in the zinc content in the sludge of about 66%. The research revealed that long hour leaching (298 K, 100 hours carried out at ambient temperatures caused a reduction in zinc content by 60% to the value of 1.15-1.2% Zn.

  1. A preferential flow leaching index

    NARCIS (Netherlands)

    McGrath, G.S.; Hinz, C.; Sivapalan, M.

    2009-01-01

    The experimental evidence suggests that for many chemicals surface runoff and rapid preferential flow through the shallow unsaturated zone are significant pathways for transport to streams and groundwater. The signature of this is the episodic and pulsed leaching of these chemicals. The driver for

  2. Submerged-arc welding slags: characterization and leaching strategies for the removal of aluminum and titanium.

    Science.gov (United States)

    Annoni, Raquel; Souza, Poliana Santos; Petrániková, Martina; Miskufova, Andrea; Havlík, Tomáš; Mansur, Marcelo Borges

    2013-01-15

    In the present study, submerged-arc welding slags were characterized by applying a variety of methods, including X-ray fluorescence, X-ray diffraction, particle size, Raman spectroscopy, and scanning electron microscope with energy dispersive X-ray analysis. The content of Al proved to be quite similar within neutral and acid slags (10-14%), while that of Ti proved to be much higher in acid slags (approximately 10%) than in neutral slags (<1%). The presence of spinel structures associated with Al species could also be identified in the analyzed samples. This characterization study was accompanied by leaching tests performed under changing operating conditions in an attempt to evaluate to what extent the Al and Ti bearing components could be removed from the slags. The leaching work involved three distinct strategies: (i) NaOH leaching followed by H(2)SO(4) leaching, (ii) acid leaching (HCl and H(2)SO(4)) using oxidizing/reducing agents, and (iii) slag calcination followed by H(2)SO(4) leaching. In the best result, 80% of Al was extracted in one single leaching stage after calcination of the acid slag with NaCl+C at 900 °C. By contrast, the removal of Ti proved to be unsatisfactory. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. A Simulator for Copper Ore Leaching

    Energy Technology Data Exchange (ETDEWEB)

    Travis, B.

    1999-05-14

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Copper is a strategic metal and the nation needs a secure supply both for industrial use and military needs. However, demand is growing worldwide and is outstripping the ability of the mining industry to keep up. Improved recovery methods are critically needed to maintain the balance of supply and demand. The goal of any process design should be to increase the amount of copper recovered, control movement of acid and other environmentally harmful chemicals, and reduce energy requirements. To achieve these ends, several improvements in current technology are required, the most important of which is a better understanding of, and the ability to quantify, how fluids move through heterogeneous materials in a complex chemical environment. The goal of this project is create a new modeling capability that couples hydrology with copper leaching chemistry . once the model has been verified and validated, we can apply the model to specific problems associated with heap leaching (flow channeling due to non-uniformities in heap structure, precipitation/dissolution reactions, and bacterial action), to understand the causes of inefficiencies, and to design better recovery systems. We also intend to work with representatives of the copper mining industry to write a coordinated plan for further model development and application that will provide economic benefits to the industry and the nation.

  4. Separating NaCl and AlCl3·6H2O Crystals from Acidic Solution Assisted by the Non-Equilibrium Phase Diagram of AlCl3-NaCl-H2O(-HCl Salt-Water System at 353.15 K

    Directory of Open Access Journals (Sweden)

    Huaigang Cheng

    2017-08-01

    Full Text Available Extracting AlCl3·6H2O from acid leaching solution through crystallization is one of the key processes to extracting aluminum from fly ash, coal gangue and other industrial solid wastes. However, the obtained products usually have low purity and a key problem is the lack of accurate data for phase equilibrium. This paper presented the non-equilibrium phase diagrams of AlCl3-NaCl-H2O (HCl salt-water systems under continuous heating and evaporation conditions, which were the main components of the acid leaching solution obtained through a sodium-assisted activation hydrochloric acid leaching process. The ternary system was of a simple eutonic type under different acidities. There were three crystalline regions; the crystalline regions of AlCl3·6H2O, NaCl and the mixture AlCl3·6H2O/NaCl, respectively. The phase diagram was used to optimize the crystallization process of AlCl3·6H2O and NaCl. A process was designed to evaporate and remove NaCl at the first stage of the evaporation process, and then continue to evaporate and crystallize AlCl3·6H2O after solid-liquid separation. The purities of the final salt products were 99.12% for NaCl and up to 97.35% for AlCl3·6H2O, respectively.

  5. Comparison of Ultrasound-Assisted and Regular Leaching of Vanadium and Chromium from Roasted High Chromium Vanadium Slag

    Science.gov (United States)

    Wen, Jing; Jiang, Tao; Gao, Huiyang; Liu, Yajing; Zheng, Xiaole; Xue, Xiangxin

    2018-02-01

    Ultrasound-assisted leaching (UAL) was used for vanadium and chromium leaching from roasted material obtained by the calcification roasting of high-chromium-vanadium slag. UAL was compared with regular leaching. The effect of the leaching time and temperature, acid concentration, and liquid-solid ratio on the vanadium and chromium leaching behaviors was investigated. The UAL mechanism was determined from particle-size-distribution and microstructure analyses. UAL decreased the reaction time and leaching temperature significantly. Furthermore, 96.67% vanadium and less than 1% chromium were leached at 60°C for 60 min with 20% H2SO4 at a liquid-solid ratio of 8, which was higher than the maximum vanadium leaching rate of 90.89% obtained using regular leaching at 80°C for 120 min. Ultrasonic waves broke and dispersed the solid sample because of ultrasonic cavitation, which increased the contact area of the roasted sample and the leaching medium, the solid-liquid mass transfer, and the vanadium leaching rate.

  6. Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

    Science.gov (United States)

    Xing, Peng; Ma, Bao-zhong; Zeng, Peng; Wang, Cheng-yan; Wang, Ling; Zhang, Yong-lu; Chen, Yong-qiang; Wang, Shuo; Wang, Qiu-yin

    2017-11-01

    Huge quantities of zinc leaching residues (ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals (mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L-1, a liquid/solid ratio of 4:1 (mL/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L-1, a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.

  7. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  8. 49 CFR 173.158 - Nitric acid.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as...

  9. Influencing factors and kinetics analysis on the leaching of iron from boron carbide waste-scrap with ultrasound-assisted method.

    Science.gov (United States)

    Li, Xin; Xing, Pengfei; Du, Xinghong; Gao, Shuaibo; Chen, Chen

    2017-09-01

    In this paper, the ultrasound-assisted leaching of iron from boron carbide waste-scrap was investigated and the optimization of different influencing factors had also been performed. The factors investigated were acid concentration, liquid-solid ratio, leaching temperature, ultrasonic power and frequency. The leaching of iron with conventional method at various temperatures was also performed. The results show the maximum iron leaching ratios are 87.4%, 94.5% for 80min-leaching with conventional method and 50min-leaching with ultrasound assistance, respectively. The leaching of waste-scrap with conventional method fits the chemical reaction-controlled model. The leaching with ultrasound assistance fits chemical reaction-controlled model, diffusion-controlled model for the first stage and second stage, respectively. The assistance of ultrasound can greatly improve the iron leaching ratio, accelerate the leaching rate, shorten leaching time and lower the residual iron, comparing with conventional method. The advantages of ultrasound-assisted leaching were also confirmed by the SEM-EDS analysis and elemental analysis of the raw material and leached solid samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores; Tratamiento de disoluciones de lixiviacion de minerales de uranio en presencia de fosfatos. Comportamiento en las etapas de ajuste de PH, cambio de ion y precipitacion de concentrados

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Aguilar, J.; Uriarte Hueda, A.

    1962-07-01

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs.

  11. MICROBIALLY MEDIATED LEACHING OF RARE EARTH ELEMENTS FROM RECYCLABLE MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D. W.; Fujita, Y.; Daubaras, D. L.; Bruhn, D. F.; Reiss, J. H.; Thompson, V. S.; Jiao, Y.

    2016-09-01

    Bioleaching offers a potential approach for recovery of rare earth elements (REE) from recyclable materials, such as fluorescent lamp phosphors or degraded industrial catalysts. Microorganisms were enriched from REE-containing ores and recyclable materials with the goal of identifying strains capable of extracting REE from solid materials. Over 100 heterotrophic microorganisms were isolated and screened for their ability to produce organic acids capable of leaching REE. The ten most promising isolates were most closely related to Pseudomonas, Acinetobacter and Talaromyces. Of the acids produced, gluconic acid appeared to be the most effective at leaching REE (yttrium, lanthanum, cerium, europium, and terbium) from retorted phosphor powders (RPP), fluidized cracking catalyst (FCC), and europium-doped yttrium oxide (YOEu). We found that an Acinetobacter isolates, BH1, was the most capable strain and able to leach 33% of the total REE content from the FCC material. These results support the continuing evaluation of gluconic acid-producing microbes for large-scale REE recovery from recyclable materials.

  12. Aluminium leaching from red mud by filamentous fungi.

    Science.gov (United States)

    Urík, Martin; Bujdoš, Marek; Milová-Žiaková, Barbora; Mikušová, Petra; Slovák, Marek; Matúš, Peter

    2015-11-01

    This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strain's respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Laboratory study on the leaching potential of spent alkaline batteries

    OpenAIRE

    Xará, Susana M.; Delgado, Julanda N.; Almeida, Manuel F.; Carlos A. Costa

    2009-01-01

    Four different leaching tests were carried out with spent alkaline batteries as an attempt to quantify the environmental potential burdens associated with landfilling. The tests were performed in columns filled up with batteries either entire or cross-cut, using either deionized water or nitric acid solution as leachant. In a first set of tests, the NEN 7343 standard procedure was followed, with leachant circulating in open circuit from bottom to top through columns. These tests w...

  14. Porosity and Permeability of Round Top Mountain Rhyolite (Texas, USA) Favor Coarse Crush Size for Rare Earth Element Heap Leach

    OpenAIRE

    Lorraine Negron; Nicholas Pingitore; Daniel Gorski

    2016-01-01

    Water-saturation porosity and dye-penetration permeability measurements of Round Top Mountain rhyolite confirm that a ½-inch (13-mm) crush size would permit efficient acid heap leaching of yttrium and heavy rare earth elements (YHREEs) hosted in yttrofluorite, a YHREE-substituted variety of fluorite. Laboratory acid leaching has extracted up to 90% of the YHREEs. The bulk insoluble gangue mineralogy of the rhyolite, 90% to 95% quartz and feldspars, assures low acid consumption. Different crus...

  15. Metal extraction from ores by heap leaching

    Science.gov (United States)

    Bartlett, Robert W.

    1997-08-01

    Heap leaching low-grade ores has become a major contributor to the extraction of economically important metals, notably copper and gold. The state-of-the-art in heap leaching is reviewed with emphasis on process engineering. Rock leaching, including rock pore diffusion and mineral kinetics, solution flow, and retention in ore heaps during percolation leaching, and bio-oxidation of sulfidic ores are covered. Oxygen transport into heaps by gaseous diffusion, natural convection, and forced air ventilation is discussed. Strategies for optimizing heap leaching include ore crushing, ore agglomeration, low-cost air ventilation of sulfide ore heaps undergoing bio-oxidation using fans, and the use of aggregate metal extraction rate constants in making metallurgical business decisions about heap leaching.

  16. Phosphorus leaching from biosolids-amended sandy soils.

    Science.gov (United States)

    Elliott, H A; O'Connor, G A; Brinton, S

    2002-01-01

    Increasing emphasis on phosphorus (P)-based nutrient management underscores the need to understand P behavior in soils amended with biosolids and manures. Laboratory and greenhouse column studies characterized P forms and leachability of eight biosolids products, chicken manure (CM), and commercial fertilizer (triple superphosphate, TSP). Bahiagrass (Paspalum notatum Flugge) was grown for 4 mo on two acid, P-deficient Florida sands, representing both moderate (Candler series: hyperthermic, uncoated Typic Quartzipsamments) and very low (Immokalee series: sandy, siliceous, hyperthermic Arenic Alaquods) P-sorbing capacities. Amendments were applied at 56 and 224 kg P(T) ha(-1), simulating P-based and N-based nutrient loadings, respectively. Column leachate P was dominantly inorganic and lower for biosolids P sources than TSP. For Candler soil, only TSP at the high P rate exhibited P leaching statistically greater (alpha = 0.05) than control (soil-only) columns. For the high P rate and low P-sorbing Immokalee soil, TSP and CM leached 21 and 3.0% of applied P, respectively. Leachate P for six biosolids was biological P removal process, exhibited significantly greater leachate P in both cake and pelletized forms (11 and 2.5% of applied P, respectively) than other biosolids. Biosolids P leaching was correlated to the phosphorus saturation index (PSI = [Pox]/[Al(ox) + Fe(ox)]) based on oxalate extraction of the pre-applied biosolids. For hiosolids with PSI < or = approximately 1.1, no appreciable leaching occurred. Only Largo cake (PSI = 1.4) and pellets (PSI = 1.3) exhibited P leaching losses statistically greater than controls. The biosolids PSI appears useful for identifying biosolids with potential to enrich drainage P when applied to low P-sorbing soils.

  17. Leaching of nano-ZnO in municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Sakallioglu, T.; Bakirdoven, M.; Temizel, I. [Institute of Environmental Sciences, Bogazici University, 34342 Istanbul (Turkey); Demirel, B., E-mail: burak.demirel@boun.edu.tr [Institute of Environmental Sciences, Bogazici University, 34342 Istanbul (Turkey); Copty, N.K.; Onay, T.T.; Uyguner Demirel, C.S. [Institute of Environmental Sciences, Bogazici University, 34342 Istanbul (Turkey); Karanfil, T. [Environmental Engineering and Earth Science, Clemson University, Clemson, SC 29634 (United States)

    2016-11-05

    Highlights: • Leaching potential of 3 different types of nano-ZnO in real fresh MSW was investigated. • Batch tests were conducted at different pH, ionic strength and ZnO concentrations. • Most of the added nano-ZnO mass was retained within the solid waste matrix. • The pH and IS conditions did not significantly influence the leaching behavior of ZnO. • A kinetic particle deposition/detachment model was developed to analyze ZnO behavior. - Abstract: Despite widespread use of engineered nanomaterials (ENMs) in commercial products and their potential disposal in landfills, the fate of ENMs in solid waste environments are still not well understood. In this study, the leaching behavior of nano ZnO -one of the most used ENMs- in fresh municipal solid waste (MSW) was investigated. Batch reactors containing municipal solid waste samples were spiked with three different types of nano ZnO having different surface stabilization. The leaching of ZnO was examined under acidic, basic and elevated ionic strength (IS) conditions. The results of the 3-day batch tests showed that the percent of the added nano-ZnO mass retained within the solid waste matrix ranged between 80% and 93% on average for the three types of nano-ZnO tested. The pH and IS conditions did not significantly influence the leaching behavior of ZnO. To further analyze the behavior of ZnO in the MSW matrix, a kinetic particle deposition/detachment model was developed. The model was able to reproduce the main trends of the batch experiments. Reaction rate constants for the batch tests ranged from 0.01 to 0.4 1/hr, reflecting the rapid deposition of nano-ZnO within the MSW matrix.

  18. Pesticide sorption and leaching potential on three Hawaiian soils.

    Science.gov (United States)

    Hall, Kathleen E; Ray, Chittaranjan; Ki, Seo Jin; Spokas, Kurt A; Koskinen, William C

    2015-08-15

    On the Hawaiian Islands, groundwater is the principal source of potable water and contamination of this key resource by pesticides is of great concern. To evaluate the leaching potential of four weak acid herbicides [aminocyclopyrachlor, picloram, metsulfuron-methyl, biologically active diketonitrile degradate of isoxaflutole (DKN)] and two neutral non-ionizable herbicides [oxyfluorfen, alachlor], their sorption coefficients were determined on three prevalent soils from the island of Oahu. Metsulfuron-methyl, aminocylcopyrachlor, picloram, and DKN were relatively low sorbing herbicides (K(oc) = 3-53 mL g(-1)), alachlor was intermediate (K(oc) = 120-150 mL g(-1)), and oxyfluorfen sorbed very strongly to the three soils (K(oc) > 12,000 mL g(-1)). Following determination of K(oc) values, the groundwater ubiquity score (GUS) indices for these compounds were calculated to predicted their behavior with the Comprehensive Leaching Risk Assessment System (CLEARS; Tier-1 methodology for Hawaii). Metsulfuron-methyl, aminocyclopyrachlor, picloram, and DKN would be categorized as likely leachers in all three Hawaiian soils, indicating a high risk of groundwater contamination across the island of Oahu. In contrast, oxyfluorfen, regardless of the degradation rate, would possess a low and acceptable leaching risk due to its high sorption on all three soils. The leaching potential of alachlor was more difficult to classify, with a GUS value between 1.8 and 2.8. In addition, four different biochar amendments to these soils did not significantly alter their sorption capacities for aminocyclopyrachlor, indicating a relatively low impact of black carbon additions from geologic volcanic inputs of black carbon. Due to the fact that pesticide environmental risks are chiefly dependent on local soil characteristics, this work has demonstrated that once soil specific sorption parameters are known one can assess the potential pesticide leaching risks. Published by Elsevier Ltd.

  19. Soil column leaching of pesticides.

    Science.gov (United States)

    Katagi, Toshiyuki

    2013-01-01

    In this review, I address the practical and theoretical aspects of pesticide soil mobility.I also address the methods used to measure mobility, and the factors that influence it, and I summarize the data that have been published on the column leaching of pesticides.Pesticides that enter the unsaturated soil profile are transported downwards by the water flux, and are adsorbed, desorbed, and/or degraded as they pass through the soil. The rate of passage of a pesticide through the soil depends on the properties of the pesticide, the properties of the soil and the prevailing environmental conditions.Because large amounts of many different pesticides are used around the world, they and their degradates may sometimes contaminate groundwater at unacceptable levels.It is for this reason that assessing the transport behavior and soil mobility of pesticides before they are sold into commerce is important and is one indispensable element that regulators use to assess probable pesticide safety. Both elementary soil column leaching and sophisticated outdoor lysimeter studies are performed to measure the leaching potential for pesticides; the latter approach more reliably reflects probable field behavior, but the former is useful to initially profile a pesticide for soil mobility potential.Soil is physically heterogeneous. The structure of soil varies both vertically and laterally, and this variability affects the complex flow of water through the soil profile, making it difficult to predict with accuracy. In addition, macropores exist in soils and further add to the complexity of how water flow occurs. The degree to which soil is tilled, the density of vegetation on the surface, and the type and amounts of organic soil amendments that are added to soil further affect the movement rate of water through soil, the character of soil adsorption sites and the microbial populations that exist in the soil. Parameters that most influence the rate of pesticide mobility in soil are

  20. Leaching of gold, silver and accompanying metals from circuit boards (PCBs waste

    Directory of Open Access Journals (Sweden)

    Jana Ficeriová

    2011-12-01

    Full Text Available Au-Ag noble metal wastes represent a wide range of waste types and forms, with various accompanying metallic elements.The presented leaching strategy for Au-Ag contained in circuit boards (PCBs aims at gaining gold and silver in the metallic form.Application of the proposed ammonium thiosulphate leaching process for the treatment of the above mentioned Au-Ag containing wastesrepresents a practical, economic and at the same time an ecological solution. The ammonium thiosulphate based leaching of gold and silverfrom PCBs waste, using crushing as a pretreatment, was investigated. It was possible to achieve 98 % gold and 93 % silver recovery within48 hours of ammonium thiosulphate leaching. This type of leaching is a better leaching procedure for recovery of gold and silver from PCBwaste than the classical toxic cyanide leaching. 84 % Cu, 82 % Fe, 77 % Al, 76 % Zn, 70 % Ni, 90 % Pd, 88 % Pb and 83 % Sn recovery ofthe accompanying metals was achieved, using sulphuric acid with hydrogen peroxide, sodium chloride and aqua regia. A four steps leachingprocess gave a very satisfactory yield and a more rapid kinetics for all observed metals solubilization than other technologies.

  1. Evaluation of leaching potential of three systemic neonicotinoid insecticides in vineyard soil

    Science.gov (United States)

    Kurwadkar, Sudarshan; Wheat, Remington; McGahan, Donald G.; Mitchell, Forrest

    2014-12-01

    Dinotefuran (DNT), imidacloprid (IMD), and thiamethoxam (THM) are commonly used neonicotinoid insecticides in a variety of agriculture operations. Although these insecticides help growers control pest infestation, the residual environmental occurrence of insecticides may cause unintended adverse ecological consequences to non-target species. In this study, the leaching behavior of DNT, IMD, and THM was investigated in soils collected from an active AgriLife Research Extension Center (AREC) vineyard. A series of column experiments were conducted to evaluate the leaching potential of insecticides under two experimental scenarios: a) individual pulse mode, and b) mixed pulse mode. In both scenarios, the breakthrough pattern of the insecticides in the mostly acidic to neutral vineyard soil clearly demonstrates medium to high leachability. Of the three insecticides studied for leaching, DNT has exhibited high leaching potential and exited the column with fewer pore volumes, whereas IMD was retained for longer, indicating lower leachability. Relative differences in leaching behavior of neonicotinoids could be attributed to their solubility with the leaching pattern IMD neonicotinoid insecticides based on the leachability indices such as groundwater ubiquity score, relative leaching potential, and partitioning between different environmental matrices through a fugacity-based equilibrium criterion model clearly indicates that DNT may pose a greater threat to aquatic resources compared to IMD and THM.

  2. Leaching of 226Ra from components of uranium mill tailings

    Science.gov (United States)

    Landa, E.R.

    1991-01-01

    A sequential extraction procedure was used to characterize the geochemical forms of 226Ra retained by mixtures of quartz sand and a variety of fine-grained rock and mineral species. These mixtures had previously been exposed to the sulfuric acid milling liquor of a simulated acid-leach uranium milling circuit. For most test cases, the major fraction of the 226Ra was extracted with 1 mol/1 NH4Cl and was deemed to be exchangeable. However, 226Ra retained by the barite-containing mixture was resistant to both 1 mol/1 NH4Cl and 1 mol/HCHCl extraction. ?? 1991.

  3. Phosphorus leaching in a soil textural gradient

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton

    2009-01-01

    exceeded the in situ leaching. However, the two application techniques did not vary significantly. In a sandy and a clay loam preferential flow paths within the soil columns caused high P leaching when slurry was applied at the soil surface. The effect increased with increasing clay content. Injection...

  4. Study on Leaching of Hexavalent Chromium from Hardened Concretes Using Tank Leaching Test

    OpenAIRE

    Takahashi, Shigeru; Sakai, Etsuo; Sugiyama, Takafumi

    2007-01-01

    Tank leaching tests were carried out to investigate the behavior of leaching trace elements from monolith samples. This study consists of two series, and the trace element used was hexavalent chromium. In Series I, the influence of the leachant/surface area of the specimen (L/S ratio) on the leaching amount was investigated. The leaching amount was found to increase with the amount of worked water. This shows that any L/S ratio can be selected in the tank leaching test. In Series II, th...

  5. Stability Analysis and Stabilization of Miduk Heap Leaching Structure, Iran

    Directory of Open Access Journals (Sweden)

    Mehdi Amini

    2013-06-01

    Full Text Available To construct copper heap leaching structures, a stepped heap of ore is placed over an isolated sloping surface and then washed with sulphuric acid. The isolated bed of such a heap consists of some natural and geosynthetic layers. Shear strength parameters between these layers are low, so they form the possible sliding surfaces of the heaps. Economic and environmental considerations call for studying such slides. In this study, firstly, results of the laboratory tests carried on the materials of the heap leaching structures bed are presented. Then, the instability mechanisms of such structures are investigated and proper approaches are summarized for their stabilization. Finally, stability of the Miduk copper heap is evaluated as a case history, and appropriate approaches and their effects are discussed for its stabilization.

  6. Development of mathematic model for coffee decaffeination with leaching method

    Directory of Open Access Journals (Sweden)

    Sukrisno Widyotomo

    2011-08-01

    Full Text Available A simple mathematic model for caffeine kinetic description during the extraction process (leaching of coffee bean was developed. A non­steady diffusion equation coupled with a macroscopic mass transfer equation for solvent was developed and them solved analytically. The kinetic of caffeine extraction from coffee bean is depend on initial caffeine content, final caffeine content, caffeine content at certain time, mass­transfer coefficient, solvent volume, surface area of coffee beans, process time, radius of coffee bean, leaching rate of caffeine, caffeine diffusivity and a are constan, solvent concentration, activation energy, temperature absolute and gas constant. Caffeine internal mass diffusivity was estimated by fitting the model to an experiment using acetic acid and liquid waste of cocoa beans fermentation. The prediction equation for leaching rate of caffeine in coffee beans has been found. It was found that Dk (m2/sec=1.345x10­7—4.1638x10­7, and kL (m/sec=2.445x10­5—5.551x10­5 by acetic acid as solvent depended on temperature and solvent concentration. The prediction equation for length of time to reduce initial caffeine content to certain concentration in coffee beans has been developed, Caffeine diffusivity (Dk and mass­transfer coefficient (kL was found respectively 1.591x 10­7—2.122x10­7 m2/sec and 4.897x10­5—6.529x10­5 m/sec using liquid waste of cocoa bean fermentation as solvent which depend on temperature and solvent concentration. Key words: Coffee, caffeine, decaffeination, leaching, mathematic model.

  7. Food engineering residues: amino acid composition of hydrolysates and application for the decontamination of metal polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, K. (GSF-Forschungszentrum, Inst. fuer Oekologische Chemie, Oberschleissheim (Germany) TU Muenchen, Lehrstuhl fuer Oekologische Chemie, Freising-Weihenstephan (Germany)); Riemschneider, P. (GSF-Forschungszentrum, Inst. fuer Oekologische Chemie, Oberschleissheim (Germany)); Bieniek, D. (GSF-Forschungszentrum, Inst. fuer Oekologische Chemie, Oberschleissheim (Germany)); Kettrup, A. (GSF-Forschungszentrum, Inst. fuer Oekologische Chemie, Oberschleissheim (Germany) TU Muenchen, Lehrstuhl fuer Oekologische Chemie, Freising-Weihenstephan (Germany))

    1994-11-01

    Several residues of the brewing industry and slaughtering offals were investigated in order to evaluate their potential as raw materials for the hydrolytic preparation of amino acid containing solutions, applicable as extractants in amelioration processes for metal polluted soils. The residues were hydrolysed with 6 mol/L hydrochloric acid and the hydrolysates were analysed for their total nitrogen, TOC, amino acid and heavy metal contents. Then, the leaching capacities of the hydrolysates were examined in a series of batch tests with a contaminated soil. High amino acid yields in relation to the weight of the air-dried raw materials were achieved with blood meal (72.5%) and poultry feather meal (56.6%). The portion of the detected amino acids of the total organic carbon content of the hydrolysates ranged from 38.9% (brewer's spent grain) to 93.6% (blood meal). In extraction tests with hydrolysates adjusted to a total amino acid concentration of 60 mmol/L and to a pH value of 7.0, maximum extraction yields of 50.3% for copper (soil content 279 mg kg[sup -1]) and 38.7% for nickel (soil content 54 mg kg[sup -1]) were reached. An increase of the hydrolysate concentration and of the pH of an amino acid mixture resulted in higher solubilisation of the metals. (orig.)

  8. Dynamic leaching test of personal computer components

    Energy Technology Data Exchange (ETDEWEB)

    Li Yadong, E-mail: yadong.li@jsums.edu [Department of Civil and Environmental Engineering, Jackson State University, Jackson, MS 39217 (United States); Richardson, Jay B.; Niu Xiaojun; Jackson, Ollie J.; Laster, Jeremy D.; Walker, Aaron K. [Department of Civil and Environmental Engineering, Jackson State University, Jackson, MS 39217 (United States)

    2009-11-15

    A dynamic leaching test (DLT) was developed and used to evaluate the leaching of toxic substances for electronic waste in the environment. The major components in personal computers (PCs) including motherboards, hard disc drives, floppy disc drives, and compact disc drives were tested. The tests lasted for 2 years for motherboards and 1.5 year for the disc drives. The extraction fluids for the standard toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) were used as the DLT leaching solutions. A total of 18 elements including Ag, Al, As, Au, Ba, Be, Cd, Cr, Cu, Fe, Ga, Ni, Pd, Pb, Sb, Se, Sn, and Zn were analyzed in the DLT leachates. Only Al, Cu, Fe, Ni, Pb, and Zn were commonly found in the DLT leachates of the PC components. Their leaching levels were much higher in TCLP extraction fluid than in SPLP extraction fluid. The toxic heavy metal Pb was found to continuously leach out of the components over the entire test periods. The cumulative amounts of Pb leached out of the motherboards in TCLP extraction fluid reached 2.0 g per motherboard over the 2-year test period, and that in SPLP extraction fluid were 75-90% less. The leaching rates or levels of Pb were largely affected by the content of galvanized steel in the PC components. The higher was the steel content, the lower the Pb leaching rate would be. The findings suggest that the obsolete PCs disposed of in landfills or discarded in the environment continuously release Pb for years when subjected to landfill leachate or rains.

  9. Dissolution of Metal Supported Spent Auto Catalysts in Acids

    Directory of Open Access Journals (Sweden)

    Fornalczyk A.

    2016-03-01

    Full Text Available Metal supported auto catalysts, have been used in sports and racing cars initially, but nowadays their application systematically increases. In Metal Substrate (supported Converters (MSC, catalytic functions are performed by the Platinum Group Metals (PGM: Pt, Pd, Rh, similarly to the catalysts on ceramic carriers. The contents of these metals make that spent catalytic converters are valuable source of precious metals. All over the world there are many methods for the metals recovery from the ceramic carriers, however, the issue of platinum recovery from metal supported catalysts has not been studied sufficiently yet. The paper presents preliminary results of dissolution of spent automotive catalyst on a metal carrier by means of acids: H2SO4, HCl, HNO3, H3PO4. The main assumption of the research was the dissolution of base metals (Fe, Cr, Al from metallic carrier of catalyst, avoiding dissolution of PGMs. Dissolution was the most effective when concentrated hydrochloric acid, and 2M sulfuric acid (VI was used. It was observed that the dust, remaining after leaching, contained platinum in the level of 0.8% and 0.7%, respectively.

  10. Cross-current leaching of indium from end-of-life LCD panels.

    Science.gov (United States)

    Rocchetti, Laura; Amato, Alessia; Fonti, Viviana; Ubaldini, Stefano; De Michelis, Ida; Kopacek, Bernd; Vegliò, Francesco; Beolchini, Francesca

    2015-08-01

    Indium is a critical element mainly produced as a by-product of zinc mining, and it is largely used in the production process of liquid crystal display (LCD) panels. End-of-life LCDs represent a possible source of indium in the field of urban mining. In the present paper, we apply, for the first time, cross-current leaching to mobilize indium from end-of-life LCD panels. We carried out a series of treatments to leach indium. The best leaching conditions for indium were 2M sulfuric acid at 80°C for 10min, which allowed us to completely mobilize indium. Taking into account the low content of indium in end-of-life LCDs, of about 100ppm, a single step of leaching is not cost-effective. We tested 6 steps of cross-current leaching: in the first step indium leaching was complete, whereas in the second step it was in the range of 85-90%, and with 6 steps it was about 50-55%. Indium concentration in the leachate was about 35mg/L after the first step of leaching, almost 2-fold at the second step and about 3-fold at the fifth step. Then, we hypothesized to scale up the process of cross-current leaching up to 10 steps, followed by cementation with zinc to recover indium. In this simulation, the process of indium recovery was advantageous from an economic and environmental point of view. Indeed, cross-current leaching allowed to concentrate indium, save reagents, and reduce the emission of CO2 (with 10 steps we assessed that the emission of about 90kg CO2-Eq. could be avoided) thanks to the recovery of indium. This new strategy represents a useful approach for secondary production of indium from waste LCD panels. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Geoenvironmental Characterisation of Heap Leach Materials at Abandoned Mines: Croydon Au-Mines, QLD, Australia

    Directory of Open Access Journals (Sweden)

    Anita Parbhakar-Fox

    2016-05-01

    Full Text Available Heap leaching is a well-established metallurgical technology which allows metal recovery (e.g., Au, Cu, U from low-grade ores. However, spent heap leach materials remaining at abandoned or historic mine sites may represent a potential source of contamination. At the Croydon Au-mines, heap leaching operations (1984–1985 were performed on mineralized rhyolites hosting sulphides including pyrite, galena, arsenopyrite and minor sphalerite. Characterization of spent heap leach materials (n = 14 was performed using established geochemical and mineralogical techniques, supplemented by automated mineralogical evaluations. Whilst these materials contained low sulphide-sulphur (0.08 to 0.41 wt % and returned innocuous paste pH values (pH 5.1 to 8.6, they were classified uncertain by net acid producing potential/net acid generating criteria. This was likely due to the reaction of secondary mineral phases (i.e., beudantite, hidalgoite, kintoreite and Fe-As-Pb oxides during these tests. It is hypothesised that during heap leaching, gangue sulphides have differentially reacted with the cyanide lixiviant, pre-conditioning the formation of these complex secondary phases during surficial oxidation, after heap leaching termination. These materials are considered to represent a moderate geoenvironmental risk as dissolved Pb in basal leachates is in excess of the World Health Organization (WHO 2006 guideline values. Considering this, these materials should be included in ongoing rehabilitation works at the site.

  12. Leaching of Oil from Tuna Fish Liver by Using Solvent of Methyl-Ethyl Ketone

    Directory of Open Access Journals (Sweden)

    Mirna Rahmah Lubis

    2013-12-01

    Full Text Available Research of oil leaching from Tuna Fish Liver has been carried out by extracting of tuna fish liver in soxhlet by using methyl-ethyl ketone as solvent. Liver of fresh tuna fish is blended, put into soxhlet, and extracted at temperatures of 60oC, 65oC, 70oC, 75oC, and 80oC. After obtaining the oil, separation between solvent and oil is carried out by distillation. Oil obtained is analyzed by testing the yield, acid number, Iodine value, viscosity, and its impurities content. Yield obtained is influenced by temperature and time of leaching. Both variables indicates that the higher the variables, the more fish liver oil obtained. Maximum yield obtained is 25.552% at operating condition of leaching temperature 80oC, and leaching duration of 5 hours.

  13. Leach-SX-EW copper revalorization from overburden of abandoned copper mine Cerovo, Eastern Serbia

    Directory of Open Access Journals (Sweden)

    Stevanović Z.

    2009-01-01

    Full Text Available Hydrometallurgical processes for copper revalorization from overburden of abandoned mine Cerovo in Eastern Serbia were studied. Paper contain results of percolation leaching tests, performed with acidic mine waters accumulated in the bottom of the former open pit, followed by solvent extraction (SX and electrowinning (EW processes on achieved copper pregnant leach solutions. Usage of accumulated waste waters was objected to minimizing the environmental hazard due to uncontrolled leaking of these waters in nearby creeks and rivers. Chemical composition of acidic mine waters used for leaching tests was: (g/dm3: Cu - 0.201; Fe - 0.095; Mn - 0.041; Zn - 0.026; Ni - 0.0004; pH value - 3.3. Copper content in overburden sample used for leaching tests was 0.21% from which 64% were oxide copper minerals. In scope of leaching tests were examined influence of leaching solution pH values and iron (III concentration on copper recovery. It was established that for 120 hours of leaching on pH=1.5 without oxidant agents, copper concentration in pregnant leach solutions enriched up to 1.08g/dm3 which was enough for copper extraction from solution with SX-EW treatment. As extraction reagent in SX circuit was used LIX-984N in a kerosene diluent. Cathode current density in electrowinning cell was 220Am-2 while electrolyte temperature was kept on 50±2oC. Produced cathode copper at the end of SX-EW process has purity of 99.95% Cu.

  14. pH-dependent leaching of dump coal ash - retrospective environmental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, A.; Djordjevic, D. [University of Belgrade, Belgrade (Serbia). Dept. of Chemistry

    2009-07-01

    Trace and major elements in coal ash particles from dump of 'Nikola Tesla A' power plant in Obrenovac near Belgrade (Serbia) can cause pollution, due to leaching by atmospheric and surface waters. In order to assess this leaching potential, dump ash samples were subjected to extraction with solutions of decreasing pH values (8.50, 7.00, 5.50, and 4.00), imitating the reactions of the alkaline ash particles with the possible alkaline, neutral, and acidic (e.g., acid rain) waters. The most recently deposited ash represents the greatest environmental threat, while 'aged' ash, because of permanent leaching on the dump, was shown to have already lost this pollution potential. On the basis of the determined leachability, it was possible to perform an estimation of the acidity of the regional rainfalls in the last decades.

  15. Cross-current leaching of indium from end-of-life LCD panels

    Energy Technology Data Exchange (ETDEWEB)

    Rocchetti, Laura; Amato, Alessia; Fonti, Viviana [Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); Ubaldini, Stefano [Institute of Environmental Geology and Geoengineering IGAG, National Research Council, Via Salaria km 29300, 00015 Montelibretti, Rome (Italy); De Michelis, Ida [Department of Industrial Engineering, Information and Economy, University of L’Aquila, Via Giovanni Gronchi 18, 67100, Zona industriale di Pile, L’Aquila (Italy); Kopacek, Bernd [ISL Kopacek KG, Beckmanngasse 51, 1140 Wien (Austria); Vegliò, Francesco [Department of Industrial Engineering, Information and Economy, University of L’Aquila, Via Giovanni Gronchi 18, 67100, Zona industriale di Pile, L’Aquila (Italy); Beolchini, Francesca, E-mail: f.beolchini@univpm.it [Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy)

    2015-08-15

    Graphical abstract: Display Omitted - Highlights: • End-of-life LCD panels represent a source of indium. • Several experimental conditions for indium leaching have been assessed. • Indium is completely extracted with 2 M sulfuric acid at 80 °C for 10 min. • Cross-current leaching improves indium extraction and operating costs are lowered. • Benefits to the environment come from reduction of CO{sub 2} emissions and reagents use. - Abstract: Indium is a critical element mainly produced as a by-product of zinc mining, and it is largely used in the production process of liquid crystal display (LCD) panels. End-of-life LCDs represent a possible source of indium in the field of urban mining. In the present paper, we apply, for the first time, cross-current leaching to mobilize indium from end-of-life LCD panels. We carried out a series of treatments to leach indium. The best leaching conditions for indium were 2 M sulfuric acid at 80 °C for 10 min, which allowed us to completely mobilize indium. Taking into account the low content of indium in end-of-life LCDs, of about 100 ppm, a single step of leaching is not cost-effective. We tested 6 steps of cross-current leaching: in the first step indium leaching was complete, whereas in the second step it was in the range of 85–90%, and with 6 steps it was about 50–55%. Indium concentration in the leachate was about 35 mg/L after the first step of leaching, almost 2-fold at the second step and about 3-fold at the fifth step. Then, we hypothesized to scale up the process of cross-current leaching up to 10 steps, followed by cementation with zinc to recover indium. In this simulation, the process of indium recovery was advantageous from an economic and environmental point of view. Indeed, cross-current leaching allowed to concentrate indium, save reagents, and reduce the emission of CO{sub 2} (with 10 steps we assessed that the emission of about 90 kg CO{sub 2}-Eq. could be avoided) thanks to the recovery of indium

  16. Leaching from municipal solid waste incineration residues

    Energy Technology Data Exchange (ETDEWEB)

    Hyks, J.

    2008-02-15

    Leaching of pollutants from Municipal Solid Waste Incineration (MSWI) residues has been investigated combining a range of laboratory leaching experiments with geochemical modeling. Special attention was paid to assessing the applicability of laboratory data for subsequent modeling with respect to presumed full-scale conditions; both sample pretreatment and actual influence of leaching conditions on the results of laboratory experiments were considered. It was shown that sample pretreatment may have large impact on leaching test data. In particular, a significant fraction of Pb was shown mobile during the washing of residues with water. In addition, drying of residues (i.e. slow oxidation) prior to leaching experiments increased the leaching of Cr significantly. Significant differences regarding the leaching behavior of individual elements with respect to (non)equilibrium conditions in column percolation experiments were observed in the study. As a result, three groups of elements were identified based on the predominant leaching control and the influence of (non)equilibrium on the results of the laboratory column experiments: I. Predominantly availability-controlled elements (e.g. Na, K, Cl) II. Solubility-controlled elements (e.g. Ca, S, Si, Al, Ba, and Zn) III. Complexation-controlled elements (e.g. Cu and Ni) With respect to the above groups it was suggested that results of laboratory column experiments can, with consideration, be used to estimate full-scale leaching of elements from Group I and II. However, in order to avoid large underestimations in the assessment of leaching from Group III, it is imperative to describe the time-dependent transport of dissolved organic carbon (DOC) in the tested system or to minimize the physical non-equilibrium during laboratory experiments (e.g. bigger column, slower flow velocity). Forward geochemical modeling was applied to simulate long-term release of elements from a MSWI air-pollution-control residue. Leaching of a

  17. Suppressing Heavy Metal Leaching through Ball Milling of Fly Ash

    Directory of Open Access Journals (Sweden)

    Zhiliang Chen

    2016-07-01

    Full Text Available Ball milling is investigated as a method of reducing the leaching concentration (often termed stablilization of heavy metals in municipal solid waste incineration (MSWI fly ash. Three heavy metals (Cu, Cr, Pb loose much of their solubility in leachate by treating fly ash in a planetary ball mill, in which collisions between balls and fly ash drive various physical processes, as well as chemical reactions. The efficiency of stabilization is evaluated by analysing heavy metals in the leachable fraction from treated fly ash. Ball milling reduces the leaching concentration of Cu, Cr, and Pb, and water washing effectively promotes stabilization efficiency by removing soluble salts. Size distribution and morphology of particles were analysed by laser particle diameter analysis and scanning electron microscopy. X-ray diffraction analysis reveals significant reduction of the crystallinity of fly ash by milling. Fly ash particles can be activated through this ball milling, leading to a significant decrease in particle size, a rise in its BET-surface, and turning basic crystals therein into amorphous structures. The dissolution rate of acid buffering materials present in activated particles is enhanced, resulting in a rising pH value of the leachate, reducing the leaching out of some heavy metals.

  18. Prevention of sulfide mineral leaching through covalent coating

    Energy Technology Data Exchange (ETDEWEB)

    K.M. Zaman; C. Chusuei; L.Y. Blue; D.A. Atwood [University of Kentucky, Lexington, KY (United States). Department of Chemistry

    2007-09-15

    The use of benzene-1,3-diamidoethanethiol as a covalent surface coating for the prevention of metal leaching was demonstrated with several sulfide minerals including cinnabar (HgS), pyrite (FeS{sub 2}), chalcopyrite (CuFeS{sub 2}), covellite (CuS), galena (PbS), realgar (As{sub 4}S{sub 4}) and sphalerite (ZnS). The minerals were coated with sufficient H2BDT to bind the surface metals in a 1:1 ratio. Leaching at pH 1, 3 and 7 was then conducted on both treated and untreated minerals. ICP and CVAFS (for mercury) analyses revealed that the coated minerals showed a dramatic reduction in metal leaching as compared to uncoated control samples. X-ray photoelectron spectroscopy indicated the formation of covalent bonds between the sulphur of the ligand and the metals from the minerals. Results indicate that it would be possible to prevent acid mine drainage through the binding of the metals in coal. 51 refs., 4 figs., 8 tabs.

  19. Solvent extraction of uranium from leach solutions obtained in processing of Polish low-grade ores.

    Science.gov (United States)

    Kiegiel, Katarzyna; Abramowska, Anna; Biełuszka, Paweł; Zakrzewska-Kołtuniewicz, Grażyna; Wołkowicz, Stanisław

    2017-01-01

    Solvent extraction of uranium from acidic and alkaline post-leaching liquors that were obtained by leaching of Polish ores is reported in this paper. The stripping of uranium from organic to aqueous phase was also studied. The synergistic mixture of 2-diethylhexylphosphoric acid (D2EHPA) and tri-n-butylphosphate (0.2 M:0.2 M) was found as a good extracting agent for uranium. Recovery of uranium was reached even 98 %. The effect of such parameters like uranium concentration and concentration of reagents used in the experiments was evaluated in advance by using a model uranium solutions.

  20. The pH-dependent leaching behavior of slags from various stages of a copper smelting process: Environmental implications.

    Science.gov (United States)

    Jarošíková, Alice; Ettler, Vojtěch; Mihaljevič, Martin; Kříbek, Bohdan; Mapani, Ben

    2017-02-01

    The leaching behaviors of primary copper (Cu) slags originating from Ausmelt, reverbatory, and converter furnaces operating under a single technological process were compared to a residual slag tailing obtained by slag re-processing via flotation and metal recovery. The EN 12457-2 leaching test, used for assessment of the hazardous properties, was followed by the CEN/TS 14997 pH-static leaching test (pH range 3-12). Both leaching experiments were coupled with a mineralogical investigation of the primary and secondary phases as well as geochemical modeling. Metals (Cd, Cu, Pb, Zn) exhibit the highest leaching at low pH. Under acidic conditions (pH 3-6), Ausmelt slag and slag tailing exhibited higher metal leaching compared to other slag types. Very low leaching of metals (far below EU limits for non-hazardous waste) was observed at natural pH (7.9-9.0) for all the studied slag samples. In contrast, relatively high leaching of As was observed over the entire pH range, especially for Ausmelt slag (exceeding the EU limit for hazardous waste by 1.7×). However, geochemical modeling and scanning electron microscopy indicated that formation of stable Ca-Cu-Pb arsenates and the binding of As to newly formed Fe (oxyhydr)oxides play an important role in efficient As immobilization at the slag-water interface. In contrast, no controls were predicted for Sb, whose leaching was almost pH-independent. Nevertheless Sb leached concentrations at natural pH were below EU limit for hazardous waste. Re-processing of primary Cu slags for metal recovery, and subsequent co-disposal of the resulting slag tailing with dolomite-rich mine tailing and local laterite is suitable for stabilizing the remaining contaminants (except Sb) and limiting their leaching into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Determination of arsenic leaching from glazed and non-glazed Turkish traditional earthenware

    Energy Technology Data Exchange (ETDEWEB)

    Henden, Emur, E-mail: emur.henden@ege.edu.tr; Cataloglu, Rengin; Aksuner, Nur

    2011-07-01

    Glazed and non-glazed earthenware is traditionally and widely used in Turkey and most of the Mediterranean and the Middle East countries for cooking and conservation of foodstuff. Acid-leaching tests have been carried out to determine whether the use of glazed and non-glazed earthenware may constitute a human health hazard risk to the consumers. Earthenware was leached with 4% acetic acid and 1% citric acid solutions, and arsenic in the leachates was measured using hydride generation atomic absorption spectrometry. Arsenic concentrations in the leach solution of non-glazed potteries varied from 30.9 to 800 {mu}g L{sup -1}, while the glazed potteries varied generally from below the limit of detection (0.5 {mu}g L{sup -1}) to 30.6 {mu}g L{sup -1}, but in one poorly glazed series it reached to 110 {mu}g L{sup -1}. Therefore, the risk of arsenic poisoning by poorly glazed and non-glazed potteries is high enough to be of concern. It appears that this is the first study reporting arsenic release from earthenware into food. - Research highlights: {yields} Non-glazed and poorly glazed earthenware may cause a serious arsenic release into food, and drinking water. {yields} Good glazing can avoid or greatly reduce arsenic leaching into food. {yields} Leaching of arsenic from earthenware may cause serious health risk. {yields} This is a pioneering work showing arsenic risk due to earthenware.

  2. Extraction of neodymium isotopes from different phases of deep sea sediments by selective leaching

    Energy Technology Data Exchange (ETDEWEB)

    Blaser, Patrick; Frank, Norbert; Boehm, Evelyn [Ruprecht-Karls-Universitaet Heidelberg (Germany); Lippold, Joerg [Universitaet Bern (Switzerland); Gutjahr, Marcus [GEOMAR, Helmholtz Centre for Ocean Research, Kiel (Germany)

    2015-07-01

    The analysis of seawater-derived neodymium (Nd) isotopes in marine sediments provides a unique proxy for deep water provenance, and thus ocean circulation, in particular in the Atlantic. Bottom water Nd is archived in different authigenic phases in the sediment. Extracting this Nd from mineral accretions bound to foraminiferal tests has lately become the preferred since most reliable method. Attempts have also been made to extract the Nd-rich authigenic fraction by leaching it off the bulk sediment and thereby use this proxy with less effort, in the highest possible resolution and in sediments where foraminifera are not sufficiently present. However, often other sedimentary components are also leached in the process and contaminate the extracted Nd. In this project several sediments across the Atlantic were leached in ten consecutive steps with two commonly used acidic solutions. The leachates were analysed on their elemental and Nd isotope compositions, as well as rare earth element (REE) distributions. By graduating the total leaching procedure into smaller stages the results display which processes take place in the course of sediment leaching in the laboratory and thus help to better evaluate the quality of sediment leaches for Nd isotope analysis.

  3. Leaching capacity of metals-metalloids and recovery of valuable materials from waste LCDs.

    Science.gov (United States)

    Savvilotidou, Vasiliki; Hahladakis, John N; Gidarakos, Evangelos

    2015-11-01

    The purpose of Directive 2012/19/EU which is related to WEEE (Waste Electrical and Electronic Equipment), also known as "e-waste", is to contribute to their sustainable production and consumption that would most possibly be achieved by their recovery, recycling and reuse. Under this perspective, the present study focused on the recovery of valuable materials, metals and metalloids from LCDs (Liquid Crystal Displays). Indium (In), arsenic (As) and stibium (Sb) were selected to be examined for their Leaching Capacity (R) from waste LCDs. Indium was selected mainly due to its rarity and preciousness, As due to its high toxicity and wide use in LCDs and Sb due to its recent application as arsenic's replacement to improve the optimal clarity of a LCD screen. The experimental procedure included disassembly of screens along with removal and recovery of polarizers via thermal shock, cutting, pulverization and digestion of the shredded material and finally leaching evaluation of the aforementioned elements. Leaching tests were conducted under various temperatures, using various solid:liquid (S/L) ratios and solvents (acid mixtures), to determine the optimal conditions for obtaining the maximum leaching capacities. The examined elements exhibited different leaching behaviors, mainly due to the considerable diversity in their inherent characteristic properties. Indium demonstrated the highest recovery percentages (approximately 60%), while the recovery of As and Sb was unsuccessful, obtaining poor leaching percentages (0.16% and 0.5%, respectively). Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Application of acid-catalyzed hydrolysis of dispersed organic solvent in developing new microencapsulation process technology.

    Science.gov (United States)

    Lee, Honghwa; Lee, Sunhwa; Bhattacharjee, Himanshu; Sah, Hongkee

    2012-01-01

    The aim of this study was to evaluate a new microencapsulation technology employing an acid-catalyzed solvent extraction method in conjunction to an emulsion-based microencapsulation process. Its process consisted of emulsifying a dispersed phase of poly(D,L-lactide-co-glycolide) and isopropyl formate in an aqueous phase. This step was followed by adding hydrochloric acid to the resulting oil-in-water emulsion, in order to initiate the hydrolysis of isopropyl formate dissolved in the aqueous phase. Its hydrolysis caused the liberation of water-soluble species, that is, isopropanol and formic acid. This event triggered continual solvent leaching out of emulsion droplets, thereby initiating microsphere solidification. This new processing worked well for encapsulation of progesterone and ketoprofen that were chosen as a nonionizable model drug and a weakly acidic one, respectively. Furthermore, the structural integrity of poly(D,L-lactide-co-glycolide) was retained during microencapsulation. The new microencapsulation technology, being conceptually different from previous approaches, might be useful in preparing various polymeric particles.

  5. Evaluation of the physico-chemical properties of acid thinned ...

    African Journals Online (AJOL)

    The effect of acid hydrolysis on the physico-chemical properties of cassava starch was investigated. The acid hydrolysed (acid thinned) starches were prepared from cassava starch with 0.1M solution of hydrochloric acid. The acid hydrolysis of starch samples were carried out at 60°C in a thermostatically controlled water ...

  6. Application of hydrochloric cyclopentolate eye drops in the mydriasis test and optometry for children with hyperopia

    Directory of Open Access Journals (Sweden)

    Hong-Ping Yin

    2016-02-01

    Full Text Available AIM:To observe and study the comprehensive application effect of hydrochloric cyclopentolate eye drops in the mydriasis test and optometry for children with hyperopia.METHODS:Eighty-four children with hyperopia who were intervened with mydriasis test and optometry in our hospital from February 2014 to March 2015 were selected as the research object,and they were intervened with mydriasis test and optometry by tropicamide or hydrochloric cyclopentolate eye drops. The diopter, pupil diameter and residual regulation before administration and at different time after administration of the two methods were compared,and the detected results of the two groups with different severity degree were compared too.RESULTS:The diopter, pupil diameter and residual regulation before administration of the two eye drops had no significant differences(all P>0.05,while the residual regulation after using hydrochloric cyclopentolate eye drops at 20, 40, 60min and 24h were all smaller than those after using tropicamide(all PP>0.05. The pupil diameter of the two groups at 48h after administration both had no significant differences to those before administration(all P>0.05.CONCLUSION:The comprehensive application effect of hydrochloric cyclopentolate eye drops in the mydriasis test and optometry of children with hyperopia is better,and its paralysis effect for ciliaris is obvious.

  7. Recovery Process of Li, Al and Si from Lepidolite by Leaching with HF

    Directory of Open Access Journals (Sweden)

    Gustavo D. Rosales

    2017-03-01

    Full Text Available This work describes the development of a new process for the recovery of Li, Al and Si along with the proposal of a flow sheet for the precipitation of those metals. The developed process is comprised of lepidolite acid digestion with hydrofluoric acid, and the subsequent precipitation of the metals present in the leach liquor. The leaching operational parameters studied were: reaction time, temperature and HF concentration. The experimental results indicate that the optimal conditions to achieve a Li extraction higher than 90% were: solid-liquid ratio, 1.82% (w/v; temperature, 123 °C; HF concentration, 7% (v/v; stirring speed, 330 rpm; and reaction time, 120 min. Al and Si can be recovered as Na3AlF6 and K2SiF6. LiF was separated from the leach liquor during water evaporation, with recovery values of 92%.

  8. Dinâmica de íons em solo ácido lixiviado com extratos de resíduos de adubos verdes e soluções puras de ácidos orgânicos Dynamic of ions in acid soil leached with green manure residues extracts and pure solutions of organic acids

    Directory of Open Access Journals (Sweden)

    Júlio Cezar Franchini

    1999-12-01

    Full Text Available A influência da aplicação de resíduos vegetais na dinâmica de íons em solos ácidos é pouco conhecida. Neste estudo, a mobilidade de íons em amostra do horizonte Bw de um Latossolo Vermelho-Escuro álico lixiviado com soluções puras de ácidos cítrico e succínico e extratos aquosos de resíduos de nabo forrageiro (Raphanus sativus e aveia-preta (Avena strigosa foi avaliada em colunas de solo (5, 10, 20 e 40 cm de altura por 4 cm de diâmetro. Após a percolação das soluções e extratos pelas colunas de solo determinaram-se, nas soluções efluentes, os teores de Ca (Ca s, Mg (Mg s, K (Ks, Al total (Al st, orgânico (Al so, monomérico (Al sm e carbono orgânico dissolvido. No solo, foram determinados os teores trocáveis de Ca (Ca tr, Mg (Mg tr, K (Ktr e Al (Al tr e o pH (CaCl2. Os ácidos cítrico e succínico aumentaram os teores de Al st e Ca s, respectivamente, causando reduções nas frações trocáveis desses elementos no solo. O extrato de aveia-preta foi mais efetivo na remoção do Ca tr e o de nabo forrageiro na do Al tr. O decréscimo de Ca tr e Al tr foi seguido do aumento do Ktr. A formação de complexos entre Ca s e Al tr com compostos orgânicos de baixo peso molecular foi sugerida como o provável mecanismo responsável pela mobilidade dos íons polivalentes no subsolo de solos ácidos após a aplicação dos extratos de resíduos vegetais e das soluções puras de ácidos orgânicos.The influence of green manure residues addition in the dynamic of ions in acid soils is not well known. In this study, ion mobility in a sample of the Bw horizon of an Dark-Red Latosol (Oxisol, leached with citric and succinic acid pure solutions and with aqueous residue extracts of black oats (Avena strigosa and oil seed radish (Raphanus sativus were evaluated in soil columns (5, 10, 20, and 40 cm long by 4 cm diameter. After the solutions and extracts passed through the soil columns, the following parameters were determined

  9. Summary of a technique for heap leach simulation on uranium ores. Open file report (final), 15 August 1977-28 August 1980

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, H.D.; Seidel, D.C.; Nichols, I.L.

    1984-04-01

    A technique was developed for simulation of heap leaching uranium ores in 2-ft-diam columns constructed such that ores as coarse as minus 4-in could be treated in bed depths from 8 to 18 ft with test condition variations. The technique consisted of the separate steps of ore preparation, column loading, charge wetting, leaching, washing, and residue recovery. For the ores studied, sulfuric acid was found to be generally superior to alkaline lixiviants. The rate of uranium extraction by acid leaching proved to be primarily a function of percolation rate, alkalinity of the ores, and oxidant requirements of the ores. Column leaching was closely comparable to field-scale heap leaching in terms of uranium extraction rate and recovery results. Acid and oxidant requirements were lower for the field-scale operation. All column tests, as well as the field-scale heap, achieved in excess of 96-pct uranium extraction on a Bear Creek, WY, ore.

  10. Leaching of low-grade copper ores: A case study for 'Kraku Bugaresku-Cementacija' deposits (Eastern Serbia

    Directory of Open Access Journals (Sweden)

    Bogdanović Grozdanka D.

    2016-01-01

    Full Text Available This paper deals with the investigation of column leaching of low-grade ores from the copper mine Cerovo, Serbia (the approximate Cu content in the ore ranges from 0.2 - 0.3 % with >10 % copper in the form of oxide minerals. The leaching experiments were performed using sulphuric acid solutions, whereby the kinetics of copper leaching was investigated with respect to acid concentration and solid to liquid ratio. The copper concentration in the leach solution ranged from 0.80 to 1.75 g dm-3. The total Cu recovery rate ranged from 30 to 56 %, whereas the recovery rate of copper oxide minerals ranged from 67 to 100 %. Furthermore, with increasing the amount of liquid phase, copper recovery increases as well, and copper oxide minerals were completely leached out. Besides copper ions, considerably high ferrous/ferric ion concentrations were achieved in the leach solution. This concentration was sufficiently high for the use of either solvent extraction or ion exchange techniques or both for further treatment of the leach solution.

  11. Application of leaching tests for toxicity evaluation of coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Tsiridis, V.; Samaras, P.; Kungolos, A.; Sakellaropoullos, G.P. [Technological Educational Institute for West Macedonia, Kozani (Greece). Dept. for Pollution Control Technology

    2006-08-15

    The toxic properties of coal fly ash samples obtained from various coal combustion power plants were evaluated in this work using physicochemical analyses and bioassays. Physicochemical analyses showed that heavy metals present in solid samples included Cr, Cu, Mn, Ni, Pb, and Zn. The results of the chemical analysis of eluates deduced by the application of standard leaching tests according to EN 12457-2 and Toxicity Characteristic Leaching Procedure (TCLP) methods indicated that the compounds contained in fly ashes could potentially be transferred to the liquid phase depending upon the leaching method used. Heavy metal concentrations were higher in TCLP eluates, indicating that the initial pH value of the leaching medium significantly affected the transfer of these elements to the liquid phase. Tests conducted with the photobacterium Vibrio fischeri (Microtox test), the crustacean Daphnia magna, and the rotifer Brachionus calyciflorus were used to assess toxicity of eluates obtained by both leaching tests. Daphnia magna was the most sensitive test organism. The EN 12457-2 method proved to be more reliable for toxicity evaluation of eluates. In contrast, the TCLP method showed some interference owing to acetic acid toxicity, and precipitation occurred after pH adjustment of eluates from acid to neutral range. The toxicity of both fly ashes and the corresponding solid leaching residues of EN 12457-2 and TCLP leaching tests was also measured using the Microtox Basic Solid phase Test. The results generated with this bioassay indicated that toxicity was greatly influenced by the pH status of the solid samples.

  12. Leaching of aluminum and iron from boiler slag generated from a typical Chinese Steel Plant.

    Science.gov (United States)

    Li, Jinping; Gan, Jinhua; Li, Xianwang

    2009-07-30

    This paper presents a new way of recycling aluminum and iron in boiler slag derived from coal combustion plants, which integrates efficient extraction and reuse of the leached pellets together. The boiler slag was pelletized together with washed coal and lime prior to sintering and then was sintered at 800-1200 degrees C for different periods to produce sintered pellets for the leaching test. An elemental analysis of aqueous solutions leached by sulfuric acid was determined by EDTA-Na(2)-ZnCl(2) titration method. The components and microstructures of the samples, sintered pellets and leached residue were examined by means of XRF, XRD and SEM. XRD analysis indicates that predominate minerals such as kaolinite, quartz, calcium silicide, hematate and metakoalin exist in the boiler slag. An aluminum extraction efficiency of 86.50% was achieved. The maximum extraction efficiency of Fe was 94.60% in the same conditions of that for the maximum extraction efficiency of Al. The extraction efficiencies of Al and Fe increased with an increase in temperature, leaching time and acidity. High Al extraction efficiency was obtained for pellets with high CaO content. The final product of alumina would be used directly for the production of metallic aluminum.

  13. Combined oxidative leaching and electrowinning process for mercury recovery from spent fluorescent lamps.

    Science.gov (United States)

    Ozgur, Cihan; Coskun, Sezen; Akcil, Ata; Beyhan, Mehmet; Üncü, Ismail Serkan; Civelekoglu, Gokhan

    2016-11-01

    In this paper, oxidative leaching and electrowinnig processes were performed to recovery of mercury from spent tubular fluorescent lamps. Hypochlorite was found to be effectively used for the leaching of mercury to the solution. Mercury could be leached with an efficiency of 96% using 0.5M/0.2M NaOCl/NaCl reagents at 50°C and pH 7.5 for 2-h. Electrowinning process was conducted on the filtered leaching solutions and over the 81% of mercury was recovered at the graphite electrode using citric acid as a reducing agent. The optimal process conditions were observed as a 6A current intensity, 30g/L of reducing agent concentration, 120min. electrolysis time and pH of 7 at the room temperature. It was found that current intensity and citric acid amount had positive effect for mercury reduction. Recovery of mercury in its elemental form was confirmed by SEM/EDX. Oxidative leaching with NaOCl/NaCl reagent was followed by electrowinning process can be effectively used for the recovery of mercury from spent fluorescent lamps. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Evaluation of the effectiveness of the filtration leaching for uranium recovery from uranium ore

    Directory of Open Access Journals (Sweden)

    Bolat Uralbekov

    2015-09-01

    Full Text Available The physical and chemical processes taking place in filtration leaching of uranium from uranium ore sample by sulphuric acid solution have been studied by modern physico-chemical methods (X-ray diffraction, scanning electron spectroscopy, electron probe microanalysis, optical emission spectroscope, ICP OES. Column leaching test was carried out for ore samples obtained from a uranium in-situ leaching (ISL mining site using deluted sulphuricacid to study the evolution of various elements concentration in the pregnant leach solution. It has been shown that the uranium in pregnant solutions appears by dissolution of calcium and magnesium carbonates and uranium minerals as well. It was found the decreasing of filtration coefficient from 0.099 m day-1 to 0.082 m day-1, due to the presence of mechanical and chemical mudding. Partial extraction of uranium (85% from the ore has been explained by the slow diffusion of sulfuric acid to the uranium minerals locates in the cracks of silicate minerals. It was concluded that the studied uranium ore sample according to adverse geotechnical parameters is not suitable for uranium extraction by filtration leaching.

  15. Concomitant Leaching and Electrochemical Extraction of Rare Earth Elements from Monazite.

    Science.gov (United States)

    Maes, Synthia; Zhuang, Wei-Qin; Rabaey, Korneel; Alvarez-Cohen, Lisa; Hennebel, Tom

    2017-02-07

    Rare earth elements (REEs) have become increasingly important in modern day technologies. Unfortunately, their recycling is currently limited, and the conventional technologies for their extraction and purification are exceedingly energy and chemical intensive. New sustainable technologies for REE extraction from both primary and secondary resources would be extremely beneficial. This research investigated a two-stage recovery strategy focused on the recovery of neodymium (Nd) and lanthanum (La) from monazite ore that combines microbially based leaching (using citric acid and spent fungal supernatant) with electrochemical extraction. Pretreating the phosphate-based monazite rock (via roasting) dramatically increased the microbial REE leaching efficiency. Batch experiments demonstrated the effective and continued leaching of REEs by recycled citric acid, with up to 392 mg of Nd L-1 and 281 mg of La L-1 leached during seven consecutive 24 h cycles. Neodymium was further extracted in the catholyte of a three-compartment electrochemical system, with up to 880 mg of Nd L-1 achieved within 4 days (at 40 A m-2). Meanwhile, the radioactive element thorium and counterions phosphate and citrate were separated effectively from the REEs in the anolyte, favoring REE extraction and allowing sustainable reuse of the leaching agent. This study shows a promising technology that is suitable for primary ores and can further be optimized for secondary resources.

  16. Nitrate role in basic cation leaching under no-till

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2011-12-01

    Full Text Available Especially under no-tillage, subsuface soil acidity has been a problem, because it depends on base leaching, which has been associated with the presence of low molecular weigth organic acids and companion anions. The objective of this study was to evaluate exchangeable base cation leaching as affected by surface liming along with annual urea side-dressing of maize and upland rice. Treatments consisted of four lime rates (0, 1500, 3000, and 6000 kg ha-1 combined with four nitrogen rates (0, 50, 100, and 150 kg ha-1 applied to maize (Zea mays and upland rice (Oryza sativa, in two consecutive years. Maize was planted in December, three months after liming. In September of the following year, pearl millet (Pennisetum glaucum was planted without fertilization and desiccated 86 days after plant emergence. Afterwards, upland rice was grown. Immediately after upland rice harvest, 18 months after surface liming, pH and N-NO3-, N-NH4+, K, Ca, and Mg levels were evaluated in soil samples taken from the layers 0-5, 5-10, 10-20 and 20-40 cm. Higher maize yields were obtained at higher N rates and 3000 kg ha-1 lime. Better results for upland rice and pearl millet yields were also obtained with this lime rate, irrespective of N levels. The vertical mobility of K, Ca and Mg was higher in the soil profiles with N fertilization. Surface liming increased pH in the upper soil layers causing intense nitrate production, which was leached along with the base cations.

  17. Leaching of lead from computer printed wire boards and cathode ray tubes by municipal solid waste landfill leachates.

    Science.gov (United States)

    Jang, Yong-Chul; Townsend, Timothy G

    2003-10-15

    The proper management of discarded electronic devices (E-waste) is an important issue for solid waste professionals because of the magnitude of the waste stream and because these devices often contain a variety of toxic metals (e.g., lead). While recycling of E-waste is developing, much of this waste stream is disposed in landfills. Leaching tests are frequently used to characterize the potential of a solid waste to leach when disposed in a landfill. In the United States, the Toxicity Characteristic Leaching Procedure (TCLP) is used to determine whether a solid waste is a hazardous waste by the toxicity characteristic. The TCLP is designed to simulate worse-case leaching in a landfill environment where the waste is co-disposed with municipal solid waste (MSW). While the TCLP is a required analysis from a regulatory perspective, the leachate concentrations measured may not accurately reflect the concentrations observed under typical landfill conditions. Another method that can be performed to assess the degree a pollutant might leach from a waste in a landfill is to use actual landfill leachate as the leaching solution. In this study, two lead-containing components found in electronic devices (printed wire boards from computers and cathode ray tubes from computers and televisions) were leached using the TCLP and leachates from 11 Florida landfills. California's Waste Extraction Test (WET) and the Synthetic Precipitation Leaching Procedure were also performed. The results indicated that the extractions using MSW landfill leachates resulted in lower lead concentrations than those by the TCLP. The pH of the leaching solution and the ability of the organic acids in the TCLP and WET to complex with the lead are factors that regulate the amount of lead leached.

  18. Investigation of Copper Ammonia Leaching from Smelter Slags: Characterization, Leaching and Kinetics

    Science.gov (United States)

    Bidari, Ehsan; Aghazadeh, Valeh

    2015-10-01

    Although ammonia leaching of copper from slags has been reported generally as a part of copper slag utilization methods, but no detailed studies have been reported in the literature. In this research, we tried to investigate the effect of different parameters on ammonia leaching of copper from copper smelting slag by identifying different copper-bearing phases and following them during leaching time. Mineralogical characterization of the smelting slag (1.7 pct Cu) was done using X-ray fluorescence, X-ray diffraction, optical microscopy, diagnostic leaching tests, and scanning electron microscopy. The characterization studies indicated that main copper-bearing species are soluble copper oxides and chalcocite along with minor amount of covellite, bornite, blister copper particles, and chalcopyrite. It was also found that only approximately 0.2 pct Cu was present in the insoluble bulk silicate phases. These results suggest that approximately 88 pct of the total copper of slag could be extracted by ammonia sulfide leaching. Leaching tests were carried out and the effects of various parameters, namely pH, ammonia concentration, temperature, presence of oxygen, stirring speed, and pulp density were examined on copper leaching. The temperature and stirring speed had the most pronounced effect on the copper leaching, whereas ammonia affected the leaching yield at low concentrations of ammonia. It was found that 78 pct of Cu could be extracted within 4 hours and under optimum conditions: T = 343 K (70 °C), 2M ammonia, pH 10.5, stirring speed = 900 rpm, pulp density = 10 pct ( w s/ v). The kinetic data were analyzed with the shrinking core models, and it was found that the leaching process is controlled by both the interfacial transfer and diffusion across the product layer and the activation energy is calculated to be 49.4 kJ mol-1.

  19. Simplified process for leaching precious metals from fuel cell membrane electrode assemblies

    Science.gov (United States)

    Shore, Lawrence [Edison, NJ; Matlin, Ramail [Berkeley Heights, NJ

    2009-12-22

    The membrane electrode assemblies of fuel cells are recycled to recover the catalyst precious metals from the assemblies. The assemblies are cryogenically embrittled and pulverized to form a powder. The pulverized assemblies are then mixed with a surfactant to form a paste which is contacted with an acid solution to leach precious metals from the pulverized membranes.

  20. CARACTERIZAÇÃO E ESTUDO DA LIXIVIAÇÃO DE METAIS DE ESCÓRIAS PROVENIENTES DA RECICLAGEM DE BATERIAS DE CHUMBO-ÁCIDO/CHARACTERIZATION AND STUDY OF LEACH METAL SLAG FROM THE RECYCLING LEAD ACID BATTERIES

    National Research Council Canada - National Science Library

    M B Andrade; W Costa; A V C Andrade

    2014-01-01

      In Brazil, the metallic lead is obtained mainly from recycled lead-acid batteries using the pyrometallurgical process, which is accompanied by the generation of a slag which features elements such...

  1. Solution of problems in hydrochloric acid removal from flue gas, caused by Si and Fl compounds as illustrated by the example of waste incineration. Final report; Loesung von Betriebsproblemen bei der Salzsaeurerueckgewinnung aus Rauchgasen, bedingt durch Silizium und Fluor-Verbindungen am Beispiel der Muellverbrennung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    Problems of encrustations during acid processing were investigated by balancing mass flow in incinerators in order to identify their causes and mechanisms. A solution was derived, and a semi-industrial test facility was constructed and tested. The cause of encrustation was silicon which causes the problems via a chemical reaction in the presence of fluorine. The mechanism was formulated and was verified by experiments. (orig.) [German] Ziel der Forschungsarbeiten war, auftretende Probleme bei der Aufbereitung von Salzsaeure, welche bei der Rauchgasreinigung in Muellverbrennungsanlagen anfaellt, zu untersuchen, Loesungsvorschlaege auszuarbeiten und diese experimentell zu pruefen. Bei den Problemen handelt es sich um Verkrustungen bestimmter Anlagenteile im Prozess der Saeureaufbereitung. Zu diesem Zweck wurden einerseits Stoffstroeme in Muellverbrennungsanlagen bilanziert, um stoffliche Ursachen fuer die Verkrustungen zu identifizieren und Aussagen zu den Mechanismen der Verkrustungen ableiten zu koennen. Andererseits wurde ein konkreter, Erfolg versprechender Loesungsansatz mit dem Bau einer entsprechenden Technikumsanlage verfahrenstechnisch umgesetzt und experimentell ueberprueft. Als verkrustungsbildende Komponente wurde bereits frueher Silizium identifiziert, welches ueber einen in sich schluessigen chemischen Mechanismus in Anwesenheit von Fluor die genannten Probleme verursachen kann. Der Mechanismus wurde formuliert und experimentell bestaetigt. (orig.)

  2. Kinetics of Leaching Calcium from Dolomite

    Directory of Open Access Journals (Sweden)

    Azizi, A.

    2011-06-01

    Full Text Available Magnesia is obtained from magnesite ore and the production process applied should remove accompanying minerals that reduce its refractoriness. Given that magnesite reservoirs are more exploited and largely exhausted, there is a growing need for production of magnesia on the basis of other magnesium minerals. Dolomite is a promising source of magnesia because it forms large deposits, is easy to exploit, and generally contains a small quantity of impurities.The kinetics of calcium leaching from dolomite by magnesium-nitrate solution has been studied. The research program included the influence of temperature, mass fraction of magnesium nitrate in solution, dolomite particle size and leaching time. Time dependence of calcium leaching is described by relevant kinetic equations. Rate coefficients, their temperature dependence and Arrhenius activation energy have been determined.

  3. Leaching of azoxystrobin and its degradation product R234886 from Danish agricultural field sites

    DEFF Research Database (Denmark)

    Jørgensen, Lisbeth Flindt; Kjær, Jeanne; Olsen, Preben

    2012-01-01

    The objective was to estimate leaching of the fungicide azoxystrobin (methyl (αE)-2-[[6-(2-cyanophenoxy)-4-pyrimidinyl]oxy]-α-(methoxymethylene)benzene-acetate) and one of its primary degradation products R234886 ([(E)-2-(2-[6-cyanophenoxy)-pyrimidin-4-yloxyl]-phenyl-3-methoxyacrylic acid], major...... through loamy soils. While azoxystrobin was generally only detected during the first couple of months following application, R234886 leached for a longer period of time and at higher concentrations (up to 2.1 μg L−1). Azoxystrobin is classified as very toxic to aquatic organisms and R234886 as very...

  4. Kinetic Study of the Leaching of Low-Grade Manganese Ores by Using Pretreated Sawdust as Reductant

    Directory of Open Access Journals (Sweden)

    Yang Sun

    2017-05-01

    Full Text Available The reductive leaching of manganese from a low-grade manganese oxide ore was investigated by using pretreated sawdust as the reductant in a sulfuric acid medium. The effects of stirring speed, liquid/solid ratio, sawdust/ore mass ratio, sulfuric acid concentration, reaction temperature, and time on the manganese extraction were examined. It was found that the leaching efficiency is strongly dependent on temperature and acid concentration. The leaching efficiency of manganese reached 94.1% under the optimal conditions: stirring speed of 300 rpm, liquid/solid ratio of 8:1, mass ratio of sawdust to ore 0.25, sulfuric acid concentration of 1 mol/L and a temperature of 363 K for 180 min. The kinetic analysis was carried out based on the shrinking core model, which indicated that the reductive leaching process was controlled by the chemical reaction. The reaction orders with respect to the sulfuric acid concentration and mass ratio of sawdust are 1.66 and 0.57, respectively. The apparent activation energy for the leaching process has been calculated using the Arrhenius expression and was found to be 51.7 kJ/mol.

  5. Performance of Different Acids on Sandstone Formations

    Directory of Open Access Journals (Sweden)

    M. A. Zaman

    2013-12-01

    Full Text Available Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Some of these reactions may result in formation damage. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. It is a mixture of hydrofluoric (HF and hydrochloric (HCl acids designed to dissolve clays and siliceous fines accumulated in the near-wellbore region. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50% to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid – Hydrofluoric with Concentration (3% HF – 12% HCl. This paper presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results calculated are porosity, permeability, and FESEM Analysis and Strength tests. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  6. Inorganic-organic hybrids originating from organosilane anchored onto leached vermiculite

    Directory of Open Access Journals (Sweden)

    Ana P. M. Alves

    2013-01-01

    Full Text Available The reactivity of clay minerals leached in grafting reactions was investigated. Precursor solids were prepared by treating the sodium vermiculites with nitric acid solutions at several concentrations. The lixiviation produced the restructured porous solids with surface area over a wide range, varying from 133 to 673 m² g- 1. The sodium and lixiviated vermiculites reacted covalently with silylating agent, 3-aminopropyltrimethoxysilane, to attach this agent onto the inorganic surface, through the free available silanols. The products were characterized by CNH elemental analysis, infrared spectroscopy, X-ray diffraction, nuclear magnetic resonance in the solid state for carbon and silicon. CHN data expressed by significant contents of anchored organic chains, up to 2.14 mmol g- 1, as the degree of leaching was increased. The success of this investigation is directly related to the leaching of the natural vermiculite, which is strongly influenced by the reactivity of the abundant original source.

  7. Simultaneous determination of butyltin and phenyltin species in sediments using ultrasound-assisted leaching

    Energy Technology Data Exchange (ETDEWEB)

    Carpinteiro, J.; Rodriguez, I.; Cela, R. [Dpto. Quimica Analitica, Nutricion y Bromatologia, Universidad de Santiago de Compostela (Spain)

    2001-08-01

    A fast and simple procedure is presented for the simultaneous leaching of butyl (mono, di and tributyl) and phenyl organotin species from sediment samples. Leached compounds are further ethylated with sodium tetraethylborate in aqueous medium, and analyzed by gas chromatography. After testing the stability of triphenyltin under different extraction conditions, ultrasound-assisted leaching at room temperature in the presence of acetic acid was been proposed as an extraction procedure compatible with the simultaneous determination of phenyl- and butyltin compounds in sediments. Recoveries between 70 and 90% were obtained for phenyl species in spiked samples prepared in the laboratory. Results for butyltin species were validated by use of the reference material PACS-2. Quantification limits, using GC-MIP-AES as measurement technique, were approximately 5-10 ng g{sup -1}. Precision in the consecutive analysis of three sediment samples varied between 3 and 10%. (orig.)

  8. Plant Biomass Leaching for Nutrient Recovery in Closed Loop Systems Project

    Science.gov (United States)

    Zeitlin, Nancy P.; Wheeler, Raymond (Compiler); Lunn, Griffin

    2015-01-01

    Plants will be important for food and O2 production during long term human habitation in space. Recycling of nutrients (e.g., from waste materials) could reduce the resupply costs of fertilizers for growing these plants. Work at NASA's Kennedy Space Center has shown that ion exchange resins can extract fertilizer (plant essential nutrients) from human waste water, after which the residual brine could be treated with electrodialysis to recover more water and produce high value chemicals (e.g., acids and bases). In habitats with significant plant production, inedible biomass becomes a major source of solid waste. To "close the loop" we also need to recover useful nutrients and fertilizer from inedible biomass. We are investigating different approaches to retrieve nutrients from inedible plant biomass, including physical leaching with water, processing the biomass in bioreactors, changing the pH of leaching processing, and/or conducting multiple leaches of biomass residues.

  9. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Rocklan; Dutech, Guy

    2014-09-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  10. Leaching of PAHs from soil, sediment and waste materials in relation to dissolved organic matter characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Roskam, G.D.; Comans, R.N.J [ECN Energy Research Centre of the Netherlands, Petten (Netherlands)

    2003-07-01

    Batch pH-static leaching experiments were performed with a number of soil, sediment and waste materials to investigate the effect of pH on the character of DOC in the leachates and its role in facilitating the leaching of PAHs. In order to investigate the relationship between DOC and PAHs more directly, PAHs were analysed in NaOH-extracts of the samples before and after flocculation of DOC. Analysis of these extracts by High Performance Size Exclusion Chromatography (HPSEC) shows that especially the larger DOC molecules are responsible for the leaching of the least soluble PAHs. The smaller and more soluble PAHs are less influenced by the amount and character of DOC. Radiotracer experiments with {sup 14}C-labelled PAHs confirm the preferential association with the higher-molecular humic acid fraction.

  11. PEP Support: Laboratory Scale Leaching and Permeate Stability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.; Buchmiller, William C.

    2010-05-21

    This report documents results from a variety of activities requested by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The activities related to caustic leaching, oxidative leaching, permeate precipitation behavior of waste as well as chromium (Cr) leaching are: • Model Input Boehmite Leaching Tests • Pretreatment Engineering Platform (PEP) Support Leaching Tests • PEP Parallel Leaching Tests • Precipitation Study Results • Cr Caustic and Oxidative Leaching Tests. Leaching test activities using the PEP simulant provided input to a boehmite dissolution model and determined the effect of temperature on mass loss during caustic leaching, the reaction rate constant for the boehmite dissolution, and the effect of aeration in enhancing the chromium dissolution during caustic leaching. Other tests were performed in parallel with the PEP tests to support the development of scaling factors for caustic and oxidative leaching. Another study determined if precipitate formed in the wash solution after the caustic leach in the PEP. Finally, the leaching characteristics of different chromium compounds under different conditions were examined to determine the best one to use in further testing.

  12. Porosity and Permeability of Round Top Mountain Rhyolite (Texas, USA Favor Coarse Crush Size for Rare Earth Element Heap Leach

    Directory of Open Access Journals (Sweden)

    Lorraine Negron

    2016-02-01

    Full Text Available Water-saturation porosity and dye-penetration permeability measurements of Round Top Mountain rhyolite confirm that a ½-inch (13-mm crush size would permit efficient acid heap leaching of yttrium and heavy rare earth elements (YHREEs hosted in yttrofluorite, a YHREE-substituted variety of fluorite. Laboratory acid leaching has extracted up to 90% of the YHREEs. The bulk insoluble gangue mineralogy of the rhyolite, 90% to 95% quartz and feldspars, assures low acid consumption. Different crush sizes were weighed, soaked in water, and reweighed over time to determine water-penetration estimated porosity. Typical porosities were 1% to 2% for gray and 3% to 8% for pink varieties of Round Top rhyolite. The same samples were re-tested after soaking in dilute sulfuric to simulate heap leaching effects. Post-leach porosity favorably increased 15% in pink and 50% in gray varieties, due to internal mineral dissolution. Next, drops of water-based writing ink were placed on rhyolite slabs up to ~10 mm thick, and monitored over time for visual dye breakthrough to the lower side. Ink penetration through 0.5 to 2.5-mm-thick slabs was rapid, with breakthrough in minutes to a few hours. Pink rhyolite breakthrough was faster than gray. Thicker slabs, 4 to 10 mm, took hours to three days for breakthrough. Porosity and permeability of the Round Top rhyolite and acid solubility of the yttrofluorite host should permit liberation of YHREEs from the bulk rock by inexpensive heap leaching at a coarse and inexpensive nominal ½-inch (13-mm crush size. The rate-limiting step in heap leach extraction would be diffusion of acid into, and back-diffusion of dissolution products out of, the crushed particles. The exceptional porosity and permeability that we document at Round Top suggest that there may be other crystalline rock deposits that economically can be exploited by a coarse-crush bulk heap leach approach.

  13. Laboratory study on the leaching potential of spent alkaline batteries.

    Science.gov (United States)

    Xará, Susana M; Delgado, Julanda N; Almeida, Manuel F; Costa, Carlos A

    2009-07-01

    Four different leaching tests were carried out with spent alkaline batteries as an attempt to quantify the environmental potential burdens associated with landfilling. The tests were performed in columns filled up with batteries either entire or cross-cut, using either deionized water or nitric acid solution as leachant. In a first set of tests, the NEN 7343 standard procedure was followed, with leachant circulating in open circuit from bottom to top through columns. These tests were extended to another leaching step where leachant percolated the columns in a closed loop process. Leachate solutions were periodically sampled and pH, conductivity, density, redox potential, sulphates, chlorides and heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were determined in the samples. The results showed that the total amount of substances leached in tests with cross-cut batteries was higher than with entire ones; zinc and sulphates were the substances found the most in the leachate solutions. In general, the amount of substances dissolved in open circuit is higher than in closed loop due to the effect of solution saturation and the absence of fresh solution addition. Results were compared with metal contents in the batteries and with legal limits for acceptance in landfill (Decision 2003/33/CE and Decree-Law 152/2002). None of the metals were meaningfully dissolved comparatively to its content in the batteries, except Hg. Despite the differences in the experiment procedure used and the one stated in the legislation (mixing, contact time and granulometry), the comparison of results obtained with cross-cut batteries using deionized water with legal limits showed that batteries studied could be considered hazardous waste.

  14. Leaching of valuable elements from thermal power plant bottom ash using a thermo-hydrometallurgical process.

    Science.gov (United States)

    Bojinova, Darinka; Teodosieva, Ralitsa

    2016-06-01

    The solid industrial wastes generated from thermal power plants (TPPs) can be considered as renewable secondary sources for recovery of valuable metals. This study presents the results from investigations that integrated a thermo-hydro-metallurgical method for treatment of bottom ash obtained from the Enel Maritsa East 3 TPP in Bulgaria. Leaching was performed with 20, 30 and 40 wt% sulphuric acid, respectively, in an autoclave at 100(o)C, 120(o)C and 140(o)C for 120, 240, 360 and 480 min, at a constant value of the liquid/solid ratio. After autoclaving, the samples (suspensions) were diluted with a constant value of water and stirring at 50(o)C for 60 min. On the basis of the experimental data the leaching efficiency (α) of the elements in the liquid phase after filtration was estimated. The leaching of aluminium increases significantly with increasing of the temperature, reaching the maximum value of 70 wt%. The highest leaching efficiency values for the other elements are as follows: Fe (86.4%), Ca (86.6%), Na (86.6%), Ni (83.3%) and Zn (83.3%). The maximum value of leaching for Mg, K, Mn, Cu and Cr is in the interval of 46-70%. © The Author(s) 2016.

  15. Retention and leaching of nitrite by municipal solid waste incinerator bottom ash under the landfill circumstance.

    Science.gov (United States)

    Yao, Jun; Kong, Qingna; Zhu, Huayue; Long, Yuyang; Shen, Dongsheng

    2015-01-01

    The retention and leaching of nitrite by municipal solid waste incinerator (MSWI) bottom ash could affect its migration in the landfill. In this study, the effect of the dosage of MSWI bottom ash as well as the variation of the landfill environmental parameters including pH, anions and organic matter on the nitrite retention and leaching behavior was investigated by batch experiments. The highest removal percentage (73.0%) of nitrite was observed when the dosage of MSWI bottom ash was 10 g L(-1) in 2 mg L(-1) nitrite solution. Further increase of the dosage would retard the retention, as the nitrite leaching from MSWI bottom ash was enhanced. The optimum retention of nitrite was observed when the pH was 5.0, while the leaching of nitrite showed a consistent reduction with the increase of pH. Besides, the presence of Cl(-), SO4(2)(-) and acetic acid could enhance the leaching of nitrite and mitigate the retention process. However, the retention of nitrite was enhanced by PO4(3)(-), which was probably due to the formation of the apatite, an active material for the adsorption of the nitrite. These results suggested that MSWI bottom ash could affect the migration of nitrite in the landfill, which was related to the variation of the landfill circumstance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. New Acid Combination for a Successful Sandstone Acidizing

    Science.gov (United States)

    Shafiq, M. U.; Mahmud, H. K. B.; Rezaee, R.

    2017-05-01

    With the development of new enhanced oil recovery techniques, sandstone acidizing has been introduced and played a pivotal role in the petroleum industry. Different acid combinations have been applied, which react with the formation, dissolve the soluble particles; thus increase the production of hydrocarbons. To solve the problems which occurred using current preflush sandstone acidizing technology (hydrochloric acid); a new acid combination has been developed. Core flooding experiments on sandstone core samples with dimensions 1.5 in. × 3 in. were conducted at a flow rate of 2 cm3/min. A series of hydrochloric-acetic acid mixtures with different ratios were tested under 150°F temperature. The core flooding experiments performed are aimed to dissolve carbonate, sodium, potassium and calcium particles from the core samples. These experiments are followed by few important tests which include, porosity-permeability, pH value, Inductively Coupled Plasma (ICP) analysis and Nuclear Magnetic Resonance (NMR measurements). All the results are compared with the results of conventional hydrochloric acid technology. NMR and porosity analysis concluded that the new acid combination is more effective in creating fresh pore spaces and thus increasing the reservoir permeability. It can be seen from the pore distribution before and after the acidizing. Prior applying acid; the large size of pores appears most frequently in the pore distribution while with the applied acid, it was found that the small pore size is most the predominant of the pore distribution. These results are validated using ICP analysis which shows the effective removal of calcium and other positive ions from the core sample. This study concludes that the combination of acetic-hydrochloric acid can be a potential candidate for the preflush stage of sandstone acidizing at high temperature reservoirs.

  17. Evaluation of gold and silver leaching from printed circuit board of cellphones.

    Science.gov (United States)

    Petter, P M H; Veit, H M; Bernardes, A M

    2014-02-01

    Electronic waste has been increasing proportionally with the technology. So, nowadays, it is necessary to consider the useful life, recycling, and final disposal of these equipment. Metals, such as Au, Ag, Cu, Sn and Ni can be found in the printed circuit boards (PCB). According to this, the aims of this work is to characterize the PCBs of mobile phones with aqua regia; obtaining "reference" values of leaching, to gold and silver, with cyanide and nitric acid, respectively; and study the process of leaching of these metals in alternative leaching with sodium thiosulfate and ammonium thiosulfate. The metals were characterized by digesting the sample with aqua regia for 1 and 2h at 60°C and 80°C. The leaching of Au with a commercial reagent (cyanide) and the Ag with HNO3were made. The leaching of Au and Ag with alternative reagents: Na2S2O3, and (NH4)2S2O3 in 0.1M concentration with the addition of CuSO4, NH4OH, and H2O2, was also studied. The results show that the digestion with aqua regia was efficient to characterize the metals present in the PCBs of mobile phones. However, the best method to solubilize silver was by digesting the sample with nitric acid. The leaching process using sodium thiosulfate was more efficient when an additional concentration of 0.015 and 0.030 M of the CuSO4 was added. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Duality properties of Gorringe Leach equations

    Science.gov (United States)

    Grandati, Yves; Bérard, Alain; Mohrbach, Hervé

    2009-02-01

    In the category of motions preserving the angular momentum direction, Gorringe and Leach exhibited two classes of differential equations having elliptical orbits. After enlarging slightly these classes, we show that they are related by a duality correspondence of the Arnold Vassiliev type. The specific associated conserved quantities (Laplace Runge Lenz vector and Fradkin Jauch Hill tensor) are then dual reflections of each other.

  19. Simulating cement microstructural evolution during calcium leaching

    NARCIS (Netherlands)

    Patel, R.A.; Perko, J.; Jacques, D.; De Schutter, G.; Van Breugel, K.; Ye, G.

    2014-01-01

    Calcium leaching is one of the important degradation mechanisms causing dissolution of the crystalline phases such as, AFm, portlandite increasing capillary porosity. Further it leads to decalcification of an amorphous C-S-H phase causing increase in the gel porosity and in turn degrading the long

  20. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    The utilization of biomass combustion ashes for forest soil liming and fertilizing has been addressed in literature. Though, a deep understanding of the ash chemical composition and leaching behavior is necessary to predict potential benefits and environmental risks related to this practice...

  1. Leaching of Plastic Additives to Marine Organisms

    NARCIS (Netherlands)

    Koelmans, A.A.; Besseling, E.; Foekema, E.M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of

  2. Implementation of the Leaching Environmental Assessment ...

    Science.gov (United States)

    LEAF provides a uniform and integrated approach for evaluating leaching from solid materials (e.g., waste, treated wastes such as by solidification/stabilization, secondary materials such as blast furnace slags, energy residuals such as coal fly ash, soil, sediments, mining and mineral processing wastes). Assessment using LEAF applies a stepwise approach that considers the leaching behavior of COPCs in response to chemical and physical factors that control and material properties across a range of plausible field conditions (US EPA, 2010). The framework provides the flexibility to tailor testing to site conditions and select the extent of testing based on assessment objectives and the level of detailed information needed to support decision-making. The main focus will be to discuss the implementation of LEAF in the US and the How to Guide that has recently been completed. To present the How To Guide for the implementation of the leaching environmental assessment framework to an international audience already familiar with comparable leaching tests in use in Europe. Will be meeting with European colleagues on their interest in expanding methods to include organics.

  3. Sulfate decomposition by bacterial leaching

    Energy Technology Data Exchange (ETDEWEB)

    Deveci, N.; Delaloglu, C.G. [Istanbul Technical Univ. (Turkey)

    1995-04-01

    Sulfate disposal is the main problem of many industrial effluents, such as excess sulfuric acid, gypsum, coal desulfurization byproducts, acid-mine waters, and general metallurgical effluents. It has been established that sulfate present in wastes can be converted to elemental sulfur by bacterial mutualism. This study presents the results of an investigation of the industrial feasibility of utilizing a biological system capable of converting hydrous calcium sulfate (gypsum) to elemental sulfur. Gypsum, which was used in this study, is a byproduct of the fertilizer industry. The biological system is referred to as a bacterial mutualism, and involves Desulfovibrio desulfuricans for sulfate conversion and Chlorobium thiosulfatophilum for hydrogen sulfide conversion. Bacterial mutualism and utilization of sulfate were investigated by means of a two-stage anaerobic system. In the first stage, a gas purge system was used for sulfate conversion to sulfide, and it was found that maximum conversion is 34%. In the second stage, a static culture system was used for sulfide conversion to sulfur with a conversion of 92%. 14 refs., 5 tabs.

  4. Leaching of polycyclic aromatic hydrocarbons from power plant lignite ash--influence of parameters important for environmental pollution.

    Science.gov (United States)

    Pergal, Miodrag M; Relić, Dubravka; Tešić, Zivoslav Lj; Popović, Aleksandar R

    2014-03-01

    Nikola Tesla B power plant (TENT B), located at the Sava River, in Obrenovac, 50 km west from the Serbian's capital, Belgrade, is the second largest coal-fired power plant in the country, consisting of two blocks, each of 620 MW capacity. In order to investigate the threat polycyclic aromatic hydrocarbons (PAHs) from deposited coal ash, obtained by coal combustion in this power plant, can represent for the surrounding environment, samples of coal ash were submitted to extraction with river water used for transport of coal ash to the dump, as well as with water of different ionic strength and acidity. It was found that, out of 16 EPA priority PAHs, only naphthalene, acenaphthylene, fluorene, phenantrene, fluoranthene, and pyrene were found in measurable concentrations in the different extracts. Their combined concentration was around 0.1 μg/L, so they do not, in terms of leached concentrations, represent serious danger for the surrounding environment. In all cases of established (and leached) PAH compounds, changes of ionic strength, acidity, or the presence of organic compounds in river water may to some extent influence the leached concentrations. However, under the examined conditions, similar to those present in the environment, leached concentrations were not more than 50 % greater than the concentrations leached by distilled water. Therefore, water desorption is likely the most important mechanism responsible for leaching of PAH compounds from filter coal ash.

  5. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds

    Directory of Open Access Journals (Sweden)

    Nigel V. Gale

    2016-08-01

    Full Text Available Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME–gas chromatography–mass spectrometry (GC-MS to qualitatively describe organic compounds in both biochar (through headspace extraction, and in the water leachates (through direct injection. Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species

  6. Long-term lessons on pesticide leaching obtained via the Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Anette E.; Olsen, Preben; Plauborg, Finn

    To avoid any unacceptable influence on the environment posed by pesticides and their degradation products, all pesticides used in the European Union needs authorization. The authorization procedure includes assessing the leaching risk of both pesticides and their degradation products...

  7. Characterization of phosphorus leaching from phosphate waste rock in the Xiangxi River watershed, Three Gorges Reservoir, China.

    Science.gov (United States)

    Jiang, Li-Guo; Liang, Bing; Xue, Qiang; Yin, Cheng-Wei

    2016-05-01

    Phosphate mining waste rocks dumped in the Xiangxi River (XXR) bay, which is the largest backwater zone of the Three Gorges Reservoir (TGR), are treated as Type I industry solid wastes by the Chinese government. To evaluate the potential pollution risk of phosphorus leaching from phosphate waste rocks, the phosphorus leaching behaviors of six phosphate waste rock samples with different weathering degrees under both neutral and acidic conditions were investigated using a series of column leaching experiments, following the Method 1314 standard of the US EPA. The results indicate that the phosphorus release mechanism is solubility-controlled. Phosphorus release from waste rocks increases as pH decreases. The phosphorus leaching concentration and cumulative phosphorus released in acidic leaching conditions were found to be one order of magnitude greater than that in neutral leaching conditions. In addition, the phosphorus was released faster during the period when environmental pH turned from weak alkalinity to slight acidity, with this accelerated release period appearing when L/S was in the range of 0.5-2.0 mL/g. In both neutral and acidic conditions, the average values of Total Phosphorus (TP), including orthophosphates, polyphosphates and organic phosphate, leaching concentration exceed the availability by regulatory (0.5 mg/L) in the whole L/S range, suggesting that the phosphate waste rocks stacked within the XXR watershed should be considered as Type II industry solid wastes. Therefore, the phosphate waste rocks deposited within the study area should be considered as phosphorus point pollution sources, which could threaten the adjacent surface-water environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Are teeth evidence in acid environment

    OpenAIRE

    Makesh Raj; Karen Boaz; N Srikant

    2013-01-01

    Aim: Teeth are the most durable structures that resist destruction more than skeletal tissue Commercially available acids can be used to destroy the body or a part, to mask human identification. The present study examines the effect of caustic acids on human dentition. Materials and Methods: Ten upper anterior teeth each were immersed in 37% hydrochloric acid (conc. HCl), 65% nitric acid (conc. HNO 3 ) and 96% sulfuric acid (conc. H 2 SO 4 ). Teeth were retrieved, washed in distilled water, d...

  9. Study of uranium leaching from industrial residues of Industrias Nucleares do Brazil S.A. (INB), Caetite, Bahia, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Formiga, Thiago S.; Morais, Carlos A., E-mail: cmorais@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Gomiero, Luiz A., E-mail: gomiero@inb.gov.b [Industrias Nucleares do Brasil S/A (INB), Caetite, BA (Brazil)

    2011-07-01

    The uraniferous district of Lagoa Real, located in the south-central region of the state of Bahia, has reserves estimated at 100,000 tons of uranium, which is enough to supply Angra I, II and III for 100 more years. The process adopted for the beneficiation of the uranium ore from Lagoa Real is heap leaching, a static process in which the ore is crushed, disposed in heaps and irrigated with a sulfuric acid solution to remove the uranium. This technique has a relatively low cost of implementation, although the yield of uranium recovery is low, with an uranium content in the leached residue of 700 {mu}g/g U{sub 3}O{sub 8} for ores with an initial content of 2,700 {mu}g/g U{sub 3}O{sub 8}. With the deepening of the mine pit, an increase in the carbonate content in the ore was noted, which required a higher acid consumption in the leaching. In order to reduce the concentration of carbonates, a study of the ore concentration by flotation column was accomplished. The flotation reject had high carbonate content, with a uranium content of about 2,300 {mu}g/g U{sub 3}O{sub 8} for flotation in one column and 1,100 {mu}g/g U{sub 3}O{sub 8} for flotation in two columns. This paper presents the study of the leaching process for the recovery of the uranium present in the residue of the heap leaching and in the carbonated residue from the flotation of the anomaly 13 ore. The results indicate the feasibility of treating the waste of the heap leaching through dynamic leaching. The study of the uranium leaching from the flotation residue through acid leaching technique indicated a recovery of 96% of uranium, however with a high consumption of acid, around 450 kg/t, showing that for this case, the most suitable technique for the process is alkaline leaching. (author)

  10. Static leaching of uraniferous shales with countercurrent circuits; Lixiviacion estatica, en contracorriente, de pizarras uraniferas

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, G.; Villarrubia, M.; Hernandez, J.

    1973-07-01

    We test different amounts of acid and the way of adding it in order to obtain the solubilization of uranium in static leaching. We also test the effects of the temperature. Finally we show the tests of solvent extraction considering the most important variables in it . In leaching we must work with 32 kg/t of acid and 40 d in order to obtain uraniums solubilization over 80%, The pregnant liquors have a high concentration of silica and we must use low organic liquid ( {<=} 3,5 % in amine) and fit the acidity of the pregnant Solutions to 4-8 g H{sub 2}SO{sub 4}/I. We show the economy of the process. (Author)

  11. Punica granatum leave extract as green corrosion inhibitor for mild steel in Hydrochloric acid

    OpenAIRE

    Abboud Y.; Chagraoui A.; Tanane O.; El Bouari A.; Hannache H.

    2013-01-01

    Leave of Punica granatum extract (LPGE) as green inhibitor for the corrosion of mild steel in 1M HCl solution was studied using weight-loss and potentiodynamic polarization measurements. The results obtained revealed that LPGE has fairly good inhibiting properties for mild steel corrosion in 1M HCl solution, with efficiency of around 94 % at a concentration of 1 g/l. The inhibition was of a mixed anodic–cathodic nature. The film which is formed over the metal surface was analysed by FT-IR spe...

  12. Corrosion inhibition of mild steel in hydrochloric acid solution by some double Schiff bases

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, N. [Payame Noor University (PNU), Shahin Shahr Branch, Isfahan (Iran, Islamic Republic of)], E-mail: N.Soltani@kashanu.ac.ir; Behpour, M.; Ghoreishi, S.M.; Naeimi, H. [Department of Chemistry, Faculty of Science, University of Kashan, Kashan (Iran, Islamic Republic of)

    2010-04-15

    The inhibition effect of four double Schiff bases on the corrosion of mild steel in 2 M HCl has been studied by polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The inhibitors were adsorbed on the steel surface according to the Langmuir adsorption isotherm model. From the adsorption isotherm, some thermodynamic data for the adsorption process were calculated and discussed. Kinetic parameters activation such as E{sub a}, {delta}H*, {delta}S* were evaluated from the effect of temperature on corrosion and inhibition processes. Quantum chemical calculations have been performed and several quantum chemical indices were calculated and correlated with the corresponding inhibition efficiencies.

  13. Polarization studies on zinc in hydrochloric acid solution containing some organic solvents

    Science.gov (United States)

    Mohamed, A. K.

    1999-05-01

    The corrosion behaviour of zinc metal in some organic solvents was tested electrochemically using galvanometric polarization measurements. The results showed that the studied organic solvents act as mixed type inhibitors. The inhibition was assumed to occur via physical adsorption of the inhibitor molecules fitting a Temkin's isotherm. The inhibition eficiency of the solvents increase in the order: glycerol>ethylene glycol>DMSO>dioxane. This order is not affected by the variation in temperature in the range 35-55 circC. The increase in temperature was found to increase the corrosion in absence and in presence of inhibitors. Some thermodynamic parameters for adsorption were also computed and discussed. Le comportement de corrosion du zinc métallique dans certains solvants organiques a été testé électrochimiquement en utilisant les mesures de polarisation galvanométrique. Les résultats ont montré que les solvants organiques étudiés agissent comme des inhibiteurs de type mixte. L'inhibition semble se produire par l'adsorption physique des molécules inhibitrices selon une isotherme de Temkin. L'efficacité d'inhibition des solvants augmente dans l'ordre suivant : glycérol>éthylène glycol>DMSO>dioxane. Cet ordre n'est pas affecté par une variation de température dans l'intervalle compris entre 35 et 55 circC. La corrosion augmente avec la température, en absence ou en présence d'inhibiteurs. Certains paramètres thermodynamiques d'adsorption ont été calculés et discutés.

  14. Characterization of secretin release in response to food and intraduodenal administration of fat and hydrochloric acid.

    Science.gov (United States)

    Draviam, E J; Gomez, G; Hashimoto, T; Miyashita, T; Hill, F L; Uchida, T; Singh, P; Greeley, G H; Thompson, J C

    1991-04-01

    The development and validation of a radioimmunoassay that detects release of secretin in plasma in response to low doses of secretagogues [intraduodenal HCl (0.033 meq/min); intraduodenal sodium oleate (0.04 mmol/min)] or an oral mixed meal in conscious dogs is described. Plasma secretin levels increased significantly (P less than 0.05) in response to an oral mixed meal in conscious dogs from a basal level of 4.0 to a peak level of 12.3 pg/ml at 15 min. Infusion of graded doses of HCl (2, 4, 8, 16, meq/hr for 30 min) intraduodenally in six dogs resulted in significant elevation of plasma secretin levels in a dose-dependent manner. The pancreatic bicarbonate and volume outputs correlated with the dosage of HCl administered and with the elevations in plasma secretin concentrations. Intraduodenal infusion of increasing doses of sodium oleate (2.4, 4.8, 9.6, and 19.2 mmol in 15-min periods) resulted in a significant (P less than 0.05) elevation of plasma levels of secretin.

  15. Anticoccidial activity of hydrochloric acid (HCl against Eimeria tenella in broiler chickens

    Directory of Open Access Journals (Sweden)

    Rao Z Abbas

    2011-05-01

    Full Text Available The present study was planned to evaluate the anticoccidial activity of the different concentrations of the HCl against Eimeria tenella infection in broiler chickens in comparison with the amprolium anticoccidial. For this purpose, a total of 198 chicks were placed 11 per pen with three pens per treatment. The different concentrations of HCl (1000ppm, 2000ppm and 3000ppm and amproilum (at the dose rate of 125ppm were given to the experimental groups in drinking water from 10 to 19th days of age. One group was kept as infected non medicated control and one as non infected non medicated control. At the 12th day of age, all the groups were inoculated orally with 75,000 sporulated oocysts except non infected non medicated control. Anticoccidial activity was evaluated on the basis of performance (weight gain, feed conversion ratio and pathogenic (oocyst score, lesion score and mortality %age parameters. Among HCl medicated groups, the maximum anticoccidial effect was seen in the group medicated with 1000ppm HCl followed by 2000ppm and 3000ppm HCl medicated groups. Amprolium and 1000ppm HCl were almost equivalent in suppressing the negative performance and pathogenic effects associated with coccidiosis (Eimeria tenella challenge. In summary, the lower doses of HCl have the potential to be used as alternative to chemotherapeutic drugs for Eimeria tenella control. It is therefore suggested that further studies should be carried out to determine the possible minimum safe levels of HCl with least toxic effects to be used as anticoccidial.

  16. Determination of nitrogen solubility in dilute pepsin hydrochloric acid solution of fishmeal: interlaboratory study.

    Science.gov (United States)

    Miller, Eric L; Bimbo, Anthony P; Walters, David E; Barlow, Stuart M; Sheridan, Berni

    2002-01-01

    A revised method to determine solubility of nitrogen in dilute pepsin, using 0.0002% pepsin in place of 0.2% in AOAC Official Method 971.09, was tested in 16 laboratories with 12 samples of fishmeal. Results were calculated according to 2 procedures: AOAC Official Method 971.09 and a method described in 1964 by researchers at the Torry Research Station (Aberdeen, Scotland), and generally referred to as the modified Torry method. Variations in the method of shaking and source of pepsin were also investigated. Pepsin solubility values were lower and more variable when calculated by the Torry procedure. The method of shaking apparently affected the result when calculated according to the Torry but not the AOAC method. The source of pepsin had no significant effect on between-laboratory variability, but a comparison of the 2 main sources within one laboratory resulted in highly significant differences. Based on this study, the International Fishmeal and Fish Oil Organization has adopted this new method, using 0.0002% pepsin but keeping the AOAC method of calculation. The type of shaker and source of pepsin are recommended but are not mandatory. The repeatability and reproducibility limits of this new method are 1.6 and 3.3% units of solubility, respectively.

  17. The Study Of Corrosion Inhibition Of Mild Steel In Hydrochloric Acid ...

    African Journals Online (AJOL)

    The corrosion behaviour of mild steel (98%) in water – 2- acetylpyridine – (4 – phenylthiosemicarbazone) PTSC) and water–2 – acetylpyridine – (4 - – methylthiosemicarbazone) MTSC) mixtures containing HCI has been studied using thermometric method. The composition of the medium was varied between 0.1 x 10-4M to ...

  18. In Vitro and In Silico Studies of Immobilized Xylanase on Zeolite Matrix Activated with Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Janatun Na’imah

    2017-09-01

    Full Text Available Xylanase is a hydrolase enzyme that can hydrolyze hemicellulose into xilo-oligosaccharide and xylose. This research is aimed to investigate the in vitro and in silico xylanase (isolated from the fungus Trichoderma viride immobilized on the zeolite matrix activated with HCl 0.4 M solution. The study was performed using in silico docking molecular methods to investigate the interaction between the xylanase primarily to its ligand. Xylanase activity was determined by reducing sugar produced (xylose by 1 mL of enzyme per minute. The optimum conditions of immobilized xylanase were measured according to the time agitation and concentration of xylanase. The time variation agitation used were 1, 2, 3, 4, and 5 hours, while variations in the concentrations of a xylanase used were 11.500, 15.653, 20.444, 25.875, and 31.944 mg/mL. The optimum conditions of immobilized xylanase was obtained in the shaking time for 3 hours at a concentration of xylanase 15.653 mg/mL and immobilized xylanase activity generated at 46.755 μg.g-1.min-1. Immobilized xylanase activity was greater than the purified xylanase (15.976 μg.mL-1.min-1. These results were due to the cofactors Al (AlO4 and Si (SiO4 of zeolite was able to increase the kinetic energy caused the reaction rate between xylanase with the larger substrates. Cofactor also increased the kinetic energy and can enhance the rate of reaction between a xylanase with its substrate, in order to give greater activity. Immobilized xylanase was stable and its reusability as much as 6 times which afforded the activity 21.331 μg.g-1.min-1 and the efficiency of 56.77%.

  19. A new online exhaust gas monitoring system in hydrochloric acid regeneration of cold rolling mills.

    Science.gov (United States)

    Tuo, Long; Zheng, Xiang; Chen, Xiong

    2017-12-01

    Measuring the content of hydrogen chloride (HCl) in exhaust gas used to take time and energy. In this paper, we introduce a new online monitoring system which can output real-time data to the monitoring center. The system samples and cools exhaust gas, and after a series of processing, it will be analyzed by a specific instrument. The core part of this system is remote terminal unit (RTU) which is designed on Cortex-A8 embedded architecture. RTU runs a scaled-down version of Linux which is a good choice of OS for embedded applications. It controls the whole processes, does data acquisition and data analysis, and communicates with monitoring center through Ethernet. In addition, through a software developed for windows, the monitoring process can be remotely controlled. The new system is quite beneficial for steel industry to do environment monitoring.

  20. Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin

    Directory of Open Access Journals (Sweden)

    Abdul Amir H. Kadhum

    2014-06-01

    Full Text Available A new coumarin derivative, N,N′-((2E,2′E-2,2′-(1,4-phenylenebis (methanylylidenebis(hydrazinecarbonothioylbis(2-oxo-2H-chromene-3-carboxamide PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear  magnetic resonance, 1H-NMR and carbon-13 nuclear magnetic resonance 13C-NMR. The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential (ECORR, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS, and electrochemical frequency modulation (EFM measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH.

  1. Corrosion Behavior of Amorphous Nickel-Valve Metal Alloys in Boiling Concentrated Nitric and Hydrochloric Acids

    OpenAIRE

    Kazuo, SHIMAMURA; Asahi, Kawashima; Katsuhiko, Asami; Koji, Hashimoto; Mitsui Engineering & Shipbuilding Co., Ltd.; The Research Institute for Iron, Steel and Other Metals

    1986-01-01

    The corrosion behavior of amorphous nickel-base alloys containing titanium, zirconium, niobium, tantalum and/or phosphorus in boiling 9 N HNO_3 solutions with and without Cr^ ion and in a boiling 6 N HCl solution was investigated. In boiling 9 N HNO_3 solutions alloys containing 20 at% or more tantalum were immune to corrosion, maintaining the metallic luster, and Ni-40~60Nb alloys showed low corrosion rates of the order of μm/year. In the boiling 6 N HCl solution only tantalum-containing all...

  2. Corrosion Behavior of Amorphous Nickel-Valve Metal Alloys in Boiling Concentrated Nitric and Hydrochloric Acids

    OpenAIRE

    Shimamura, Kazuo; Kawashima, Asahi; ASAMI, Katsuhiko; Hashimoto, Koji

    1986-01-01

    The corrosion behavior of amorphous nickel-base alloys containing titanium, zirconium, niobium, tantalum and/or phosphorus in boiling 9 N HNO_3 solutions with and without Cr^ ion and in a boiling 6 N HCl solution was investigated. In boiling 9 N HNO_3 solutions alloys containing 20 at% or more tantalum were immune to corrosion, maintaining the metallic luster, and Ni-40?60Nb alloys showed low corrosion rates of the order of μm/year. In the boiling 6 N HCl solution only tantalum-containing all...

  3. Corrosion Behavior of Ni3(Si,Ti in Hydrochloric Acid Solution

    Directory of Open Access Journals (Sweden)

    Gadang Priyotomo

    2013-06-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The corrosion behaviour of the intermetallic compounds Ni3(Si,Ti (L12: single phase, has been investigated using an immersion test, electrochemical method, scanning electron microscope in 0.5 kmol/m3 HCl at 303 K. In addition, the corrosion behaviour of austenitic stainless steel type 304 and C276 was studied under the same experimental conditions as references. It was found that the intergranular attack was observed for Ni3(Si,Ti in the immersion test. From the immersion test and polarization curves, Ni3(Si,Ti had the moderate corrosion resistance, while the corrosion resistances of C 276 and type 304 were the highest and the lowest. Ni3(Si,Ti and type 304 were difficult to form a stable passive film, but not for C276. A further experiment must be conducted to clarify the stability of film for Ni3(Si,Ti in detail.

  4. Corrosion inhibition of mild steel by N(4-substituted thiosemicarbazone in hydrochloric acid media

    Directory of Open Access Journals (Sweden)

    Sam John

    2017-06-01

    Full Text Available Two N(4-substituted thiosemicarbazones, anisoin- and furoin N(4-methyl(phenyl thiosemicarbazone (AMPTSC and FMPTSC, respectively have been tested as inhibitors on the corrosion of mild steel in 1 M HCl solution using electrochemical impedance spectroscopy (EIS, potentiodynamic polarization (PDP methods, adsorption studies and surface morphological studies. Polarization measurements revealed the mixed type inhibitor character. The inhibiting action of these molecules is discussed in terms of blocking the electrode surface by the adsorption of inhibitor molecules obeying Langmuir isotherm. The lowest corrosion rate was obtained with FMPTSC. Surface morphological studies also gave unfailing results.

  5. A novel imidazoline derivative as corrosion inhibitor for P110 carbon steel in hydrochloric acid environment

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2015-09-01

    Full Text Available A novel imidazoline derivative, 2-methyl-4-phenyl-1-tosyl-4, 5-dihydro-1H-imidazole (IMI, was prepared and investigated as corrosion inhibitor for P110 carbon steel in 1.0 M HCl solution by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS tests. The inhibition efficiency increased with the rising concentration of IMI inhibitor. The test results and fitting data indicated that the IMI behaved as a mixed-type inhibitor and obeys the Langmuir adsorption isotherm. Scanning electron microscopy (SEM was carried out to investigate the surface of carbon steel specimens, showing great protection from aggressive solution. Finally, inhibition mechanism of IMI on metal surface was further discussed.

  6. ON THE USE OF HYDROCHLORIC ACID FOR DETERMINING SOLID-PHASE ARSENIC PARTITIONING IN ANOXIC SEDIMENTS

    Science.gov (United States)

    One of the challenges in assessing the current impact of the discharge of arsenic contaminated ground water into a surface water body is differentiating the arsenic ground water flux versus dissolution of in-place contaminated sediments. Results from a field study at a Superfund...

  7. HYDROLYSIS OF MTBE TO TBA IN GROUND WATER SAMPLES WITH HYDROCHLORIC ACID

    Science.gov (United States)

    Conventional sampling and analytical protocols have poor sensitivity for fuel oxygenates that are alcohols, such as tert-butyl alcohol (TBA). Because alcohols are miscible or highly soluble in water, alcohols are not efficiently transferred to the gas chromatograph for analysis....

  8. Anion-exchange separation of Pt and Pd using perchloric and hydrochloric acid solutions

    Science.gov (United States)

    Petrie, R.K.; Morgan, J.W.

    1982-01-01

    On Biorad Ag-1X8 anion-exchange resin (200-400 mesh), Pd and Pt may be separated from one another by elution with 0.2M HClO4, and 5M HClO4, respectively. If present, Au may be retained by making the elutriants 0.003M in HCl. Alternatively, reduction by H2SO3 enables elution of Pt2+ with 6M HCl before recovery of Pd2+ with 0.2M HClO4??Ir4+ is reduced to Ir3+ by H2SO3 and may be eluted ahead of Pt2+ by 2M HCl. ?? 1982 Akade??miai Kiado??.

  9. Separation of calcium-48 isotope by crown ether chromatography using ethanol/hydrochloric acid mixed solvent.

    Science.gov (United States)

    Okumura, Shin; Umehara, Saori; Fujii, Yasuhiko; Nomura, Masao; Kaneshiki, Toshitaka; Ozawa, Masaki; Kishimoto, Tadafumi

    2015-10-09

    Benzo-18-crown-6 ether resin embedded in porous silica beads was synthesized and used as the packing material for chromatographic separation of (48)Ca isotope. The aim of the present work is to develop efficient isotope enrichment process for double β decay nuclide (48)Ca. To this end, ethanol/HCl mixed solvent was selected as the medium for the chromatographic separation. Adsorption of calcium on the resin was studied at different HCl concentrations and different ethanol mixing ratios in batch-wise experiments. A very interesting phenomenon was observed; Ca adsorption is controlled not by the overall HCl concentration of the mixed solvent, but by the initial concentration of added HCl solution. Calcium break-through chromatography experiments were conducted by using 75v/v% ethanol/25v/v% 8M HCl mixed solvent at different flow rates. The isotope separation coefficient between (48)Ca and (40)Ca was determined as 3.8×10(-3), which is larger than that of pure HCl solution system. Discussion is extended to the chromatographic HETP, height equivalent to a theoretical plate. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. HYDROLYSIS OF MTBE IN GROUND WATER SAMPLES PRESERVED WITIH HYDROCHLORIC ACID

    Science.gov (United States)

    Conventional sampling and analytical protocols have poor sensitivity for fuel oxygenates that are alcohols, such as TBA. Because alcohols tend to stay with the water samples, they are not efficiently transferred to the gas chromatograph for separation and analysis. A common tec...

  11. Thiosemicarbazide and thiocarbohydrazide functionalized chitosan as ecofriendly corrosion inhibitors for carbon steel in hydrochloric acid solution.

    Science.gov (United States)

    Chauhan, Dheeraj Singh; Ansari, K R; Sorour, A A; Quraishi, M A; Lgaz, H; Salghi, R

    2017-10-10

    Organically functionalized chitosan macromolecules namely Chitosan-Thiosemicarbazide (CS-TS) and Chitosan-Thiocarbohydrazide (CS-TCH) were synthesized and evaluated as new corrosion inhibitors for mild steel corrosion in 1M HCl. The FTIR and (1)H NMR studies confirmed the formation of the derivatives. The corrosion tests were performed using weight loss method, electrochemical measurements, surface morphology (AFM), quantum chemical investigation and molecular dynamics simulation methods. The maximum efficiency of 92% was obtained at a concentration as low as 200mgL(-1). The inhibitors were found to obey Langmuir adsorption isotherm and exhibited both physical and chemical adsorption. Electrochemical impedance spectroscopy (EIS) results showed an increase in polarization resistance which supported the adsorption of inhibitors on the mild steel surface. Tafel data showed a mixed type behavior with cathodic predominance. The data of quantum chemical calculations and molecular dynamics simulation supported the experimental findings. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Simultaneous Recovery of Hydrogen and Chlorine from Industrial Waste Dilute Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    N. Paidimarri

    2016-01-01

    Full Text Available Recovery of chlorine from byproduct HCl has inevitable commercial importance in industries lately because of insufficient purity or too low concentration to recycle it. Instead it is being neutralized in industries before disposing to meet stringent environmental conditions. Although recovery through catalytic oxidation processes is studied since the 19th century, their high operating conditions combined with sluggish reaction kinetics and low single pass conversions make electrolysis a better alternative. The present motive of this work is to develop a novel electrolysis process which in contrast to traditional processes effectively recovers both hydrogen and chlorine from dilute HCl. For this, an electrolytic cell with an Anionic Exchange Membrane has been designed which only allows the passage of chlorine anions from catholyte to anolyte separating the gasses in a single step. The catholyte can be as low as 3.59 wt% because of fixed anolyte concentration of 1.99 wt% which minimizes oxygen formation. Preliminary results show that the simultaneous recovery of hydrogen and chlorine is possible with high conversion up to 98%. The maximum current density value for 4.96 cm2 membrane surface area (70% active surface area is 2.54 kAm−2, which is comparable with reported commercial processes. This study is expected to be useful for process intensification of the same in a continuous process environment.

  13. Electrochemical Study on Newly Synthesized Chlorocurcumin as an Inhibitor for Mild Steel Corrosion in Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Ahmed A. Al-Amiery

    2013-11-01

    Full Text Available A new curcumin derivative, i.e., (1E,4Z,6E-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenylhepta-1,4,6-trien-3-one (chlorocurcumin, was prepared starting with the natural compound curcumin. The newly synthesized compound was characterized by elemental analysis and spectral studies (IR, 1H-NMR and 13C-NMR. The corrosion inhibition of mild steel in 1 M HCl by chlorocurcumin has been studied using potentiodynamic polarization (PDP measurements and electrochemical impedance spectroscopy (EIS. The inhibition efficiency increases with the concentration of the inhibitor but decreases with increases in temperature. The potentiodynamic polarization reveals that chlorocurcumin is a mixed-type inhibitor. The kinetic parameters for mild steel corrosion were determined and discussed.

  14. Inhibition of copper corrosion in aerated hydrochloric acid solution by heterocyclic compounds containing a mercapto group

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Daquan; Gao Lixin; Zhou Guoding

    2004-12-01

    Inhibition of copper corrosion by benzotriazole (BTA), 2-mercapto benzoxazole (MBO) and 2-mercapto benzimidazole (MBI) in 0.5 mol L{sup -1} HCl was investigated by weight-loss measurements, potentiodynamic polarization curves and electrochemical impedance spectroscopy. MBI was shown to be the most effective inhibitor among those tested. Potentiodynamic polarization results revealed that the three compounds acted as anodic inhibitors, particularly MBI strongly suppressed anodic current densities. Molecular structure parameters of BTA, MBO and MBI were obtained by using an MM2 forcefield program and PPP-SCF quantum chemical calculation. It was found that MBI has higher levels of HOMO and LUMO energy and the larger {pi}-electron density.

  15. Adsorption and inhibitive properties of sildenafil (Viagra for zinc in hydrochloric acid solution

    Directory of Open Access Journals (Sweden)

    A.S. Fouda

    Full Text Available Sildenafil (Viagra was investigated as corrosion inhibitor for Zn in 1 M HCl solution using chemical and electrochemical methods at 25 °C. Electrochemical results showed that this drug is efficient inhibitor for Zn in HCl and the inhibition efficiency (IE reached to 91% at 300 ppm. The IE increases with the drug concentration and decreases with increasing temperature. The adsorption of this drug on Zn surface follows Langmuir adsorption isotherm. The polarization plots revealed that Sildenafil acts as a mixed-type inhibitor. The thermodynamic parameters of activation and adsorption were calculated and discussed. The surface morphology of the Zn specimens was evaluated using scanning electron microscope (SEM, energy dispersive X-ray (EDX, atomic force microscopy (AFM and Fourier transform infrared spectroscopy (FTIR techniques. Keywords: Zn, Corrosion inhibition, HCl, SEM, EDX, AFM, FTIR, Sildenafil drug

  16. Adsorption and inhibitive properties of sildenafil (Viagra) for zinc in hydrochloric acid solution

    Science.gov (United States)

    Fouda, A. S.; Ibrahim, H.; Atef, M.

    Sildenafil (Viagra) was investigated as corrosion inhibitor for Zn in 1 M HCl solution using chemical and electrochemical methods at 25 °C. Electrochemical results showed that this drug is efficient inhibitor for Zn in HCl and the inhibition efficiency (IE) reached to 91% at 300 ppm. The IE increases with the drug concentration and decreases with increasing temperature. The adsorption of this drug on Zn surface follows Langmuir adsorption isotherm. The polarization plots revealed that Sildenafil acts as a mixed-type inhibitor. The thermodynamic parameters of activation and adsorption were calculated and discussed. The surface morphology of the Zn specimens was evaluated using scanning electron microscope (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) techniques.

  17. Process development for recovery of copper and precious metals from waste printed circuit boards with emphasize on palladium and gold leaching and precipitation.

    Science.gov (United States)

    Behnamfard, Ali; Salarirad, Mohammad Mehdi; Veglio, Francesco

    2013-11-01

    A novel hydrometallurgical process was proposed for selective recovery of Cu, Ag, Au and Pd from waste printed circuit boards (PCBs). More than 99% of copper content was dissolved by using two consecutive sulfuric acid leaching steps in the presence of H2O2 as oxidizing agents. The solid residue of 2nd leaching step was treated by acidic thiourea in the presence of ferric iron as oxidizing agent and 85.76% Au and 71.36% Ag dissolution was achieved. The precipitation of Au and Ag from acidic thiourea leachate was investigated by using different amounts of sodium borohydride (SBH) as a reducing agent. The leaching of Pd and remained gold from the solid reside of 3rd leaching step was performed in NaClO-HCl-H2O2 leaching system and the effect of different parameters was investigated. The leaching of Pd and specially Au increased by increasing the NaClO concentration up to 10V% and any further increasing the NaClO concentration has a negligible effect. The leaching of Pd and Au increased by increasing the HCl concentration from 2.5 to 5M. The leaching of Pd and Au were endothermic and raising the temperature had a positive effect on leaching efficiency. The kinetics of Pd leaching was quite fast and after 30min complete leaching of Pd was achieved, while the leaching of Au need a longer contact time. The best conditions for leaching of Pd and Au in NaClO-HCl-H2O2 leaching system were determined to be 5M HCl, 1V% H2O2, 10V% NaClO at 336K for 3h with a solid/liquid ratio of 1/10. 100% of Pd and Au of what was in the chloride leachate were precipitated by using 2g/L SBH. Finally, a process flow sheet for the recovery of Cu, Ag, Au and Pd from PCB was proposed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Phosphorus recovery and leaching of trace elements from incinerated sewage sludge ash (ISSA).

    Science.gov (United States)

    Fang, Le; Li, Jiang-Shan; Guo, Ming Zhi; Cheeseman, C R; Tsang, Daniel C W; Donatello, Shane; Poon, Chi Sun

    2017-11-08

    Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H2SO4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Utilizing ultrasonic energy for reduction of free fatty acids in crude ...

    African Journals Online (AJOL)

    Different common types of acid catalysts (sulfuric acid, methanesulfonic acid and hydrochloric acid) were optimized to investigate the catalytic activity of each acid in the pre-treatment of CPO by the esterification process. Ultrasonic energy was used for the reduction of FFA in CPO. FFA content was measured at different ...

  20. Experimental study on leaching tests applied to MSW ashes for their disposal/reuse; Indagine sperimentale sui test di caratterizzazione dei residui di combustione ai fini del loro smaltimento/riutilizzo

    Energy Technology Data Exchange (ETDEWEB)

    Andreottola, G. [Trento Univ. (Italy), Dip. Ingegneria Civile e Ambientale; Cossu, R.; Muntoni, A. [Cagliari Univ. (Italy), DIGITA, Dip. di Geoingegneria e Tecnologie Ambientali

    1996-03-01

    In the present paper the results of an experimental study on MSW ashes leaching properties are presented and discussed. Both conventional hatch leaching tests like CO, and acetic acid tests and non-conventional ones, like the Maximum Availability and column tests have been used and compared for the evaluation of the environmental impact of MSW ashes reuse or disposal. Leaching tests have been applied on raw ashes, classified ashes and solidified/stabilized ashes.