WorldWideScience

Sample records for air-pollution-control residues leaching

  1. Geochemical modeling of leaching from MSVI air-pollution-control residues

    DEFF Research Database (Denmark)

    Astrup, Thomas; Dijkstra, J.J.; Comans, R.N.J.;

    2006-01-01

    This paper provides an improved understanding of the leaching behavior of waste incineration air-pollution-control (APC) residues in a long-term perspective. Leaching was investigated by a series of batch experiments reflecting leaching conditions after initial washout of highly soluble salts fro...

  2. Geochemical modeling of leaching from MSWI air-pollution control residues

    NARCIS (Netherlands)

    Astrup, T.; Dijkstra, J.J.; Comans, R.N.J.; Sloot, van der H.A.; Christensen, T.H.

    2006-01-01

    This paper provides an improved understanding of the leaching behavior of waste incineration air-pollution-control (APC) residues in a long-term perspective. Leaching was investigated by a series of batch experiments reflecting leaching conditions after initial washout of highly soluble salts from r

  3. Long-term leaching from MSWI air-pollution-control residues: Leaching characterization and modeling

    DEFF Research Database (Denmark)

    Hyks, Jiri; Astrup, Thomas; Christensen, Thomas Højlund

    2009-01-01

    Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sri, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column...... percolation experiments; liquid-to-solid (L/S) ratios of 200-250 L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the Course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co...

  4. Leaching behavior of Pb and Zn in air pollution control residues and their modeling prediction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; HE Pin-jing; SHAO Li-ming; FENG Jun-hui; CAO Qun-ke

    2006-01-01

    Increasing attention has been paid to air pollution control (APC) residues in China recently due to the rising proportion of waste incineration and the hazardous characteristics of the residues, among which heavy metal leaching toxicity plays an important role. Leaching behavior and potential risk of Pb and Zn in the APC residues from a Shanghai municipal solid waste (MSW) incinerator was studied, based on the leaching tests under different conditions and theoretical calculation using a geochemical thermodynamic equilibrium model MINTEQA2. Results showed that, extractant species and liquid to solid (L/S) ratio predominantly controlled the leaching toxicity of Pb and Zn, while ionic strength, vibration method and leaching time had less effect on the metals release.Leachate/final pH determined the metal leaching behavior, which changed the speciation of heavy metals in the extraction system. The equilibrium aqueous speciation, precipitation-dissolution of Pb and Zn was investigated according to the model computation, which was well in agreement with the experimental results.

  5. Influences of ammonia contamination on leaching from air-pollution-control residues.

    Science.gov (United States)

    Guan, Zhenzhen; Chen, Dezhen; Astrup, Thomas Fruergaard

    2014-12-01

    Application of selective non-catalytic reduction systems at municipal solid waste incinerators (MSWIs) often involves over-stoichiometric injection of ammonia into flue gases. Un-reacted ammonia may be deposited on fly ash particles and can ultimately influence the leaching behaviour of air-pollution-control (APC) residues. Batch tests were conducted to investigate the impacts of ammonia levels on leaching of a range of metals (sodium, potassium, calcium, aluminium, chromium, iron, lead, cadmium, copper, nickel and zinc), as well as chloride and dissolved organic carbon (DOC). Specific conductivity was also identified to reflect the soluble components. The results showed that with ammonia concentrations rising from a background level of 4 to 26,400 mg l(-1), the specific conductivity increased by 2-7 times as pH varied from alkaline to acidic values. DOC release was also significantly enhanced with high ammonia levels of 1400 mg l(-1) or higher at pH > 9; however at these high ammonia concentrations, the role of DOC in cadmium, copper, nickel and zinc leaching was negligible. Based on the experimental data, chloride, sodium and potassium were leached at high concentrations regardless of pH and ammonia concentrations. For aluminium, chromium, iron and lead, ammonia had little impact on their leaching behaviour. With respect to cadmium, copper, nickel and zinc, high ammonia concentrations significantly increased leaching in the pH range of 8-12 due to the formation of metal-ammonia complexes, which was also proved in the speciation calculations. However, the overall results suggest that typical levels of ammonia injection in MSWIs are not likely to affect metal leaching from APC residues. PMID:25147306

  6. Leaching Behavior of Circulating Fluidised Bed MSWI Air Pollution Control Residue in Washing Process

    Directory of Open Access Journals (Sweden)

    Zhiliang Chen

    2016-09-01

    Full Text Available In this study, air pollution control (APC residue is conducted with water washing process to reduce its chloride content. A novel electrical conductivily (EC measurement method is proposed to monitor the dynamic change of chloride concentrations in leachate as well as the chloride content of the residue. The method equally applies to various washing processes with different washing time, liquid/solid ratio and washing frequency. The results show that washing effectively extracts chloride salts from APC residues, including those from circulating fluidized bed (CFB municipal solid waste incineration (MSWI. The most appropriate liquid/solid ratio and washing time in the first washing are found to be around 4 L water per kg of APC residue and 30 min, respectively, and washing twice is required to obtain maximum dissolution. The pH value is the major controlling factor of the heavy metals speciation in leachate, while chloride concentration also affects the speciation of Cd. Water washing causes no perceptible transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs from the APC residue to leachate. The chloride concentration is strongly related with electrical conductivity (EC, as well as with the concentrations of calcium, sodium and potassium of washing water. Their regression analyses specify that soluble chloride salts and EC could act as an indirect indicator to monitor the change of chloride concentration and remaining chloride content, thus, contributing to the selection of the optimal washing conditions.

  7. Assessment of long-term leaching from waste incineration air-pollution-control residues

    DEFF Research Database (Denmark)

    Astrup, Thomas; Mosbæk, Hans; Christensen, Thomas Højlund

    2006-01-01

    leached with respect to L/S. The estimated long-term leaching from a semi-dry residue and a fly ash was compared with short-term leaching determined by batch tests at L/S 10l/kg, both carbonated and non-carbonated versions of the residues were investigated. Generally, very high L/S ratios above 2000l....../kg were required to leach 20–30% of the solid contents. However, Ca and S were depleted at L/S 200–900l/kg. The long-term leachate concentrations were found to either remain at the same level as the initial leaching determined by the L/S 10 batch test, or to significantly decrease compared...

  8. Influences of ammonia contamination on leaching from air-pollution-control residues

    DEFF Research Database (Denmark)

    Guan, Zhenzhen; Chen, Dezhen; Astrup, Thomas Fruergaard

    2014-01-01

    Application of selective non-catalytic reduction systems at municipal solid waste incinerators (MSWIs) often involves over-stoichiometric injection of ammonia into flue gases. Un-reacted ammonia may be deposited on fly ash particles and can ultimately influence the leaching behaviour of air-pollution...

  9. Electrodialytic remediation of air pollution control residues

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland

    Air pollution control (APC) residue from municipal solid waste incineration (MSWI) consists of the fly ash, and, in dry and semi-dry systems, also the reaction products from the flue gas cleaning process. APC residue is considered a hazardous waste due to its high alkalinity, high content of salts...... solutions are concerned with deposition; e.g. in abandoned mines. A demand for more environmentally friendly alternatives exists. Electrodialysis could be such an alternative, and the potential is being explored. Some main challenges are the extremely high soluble fraction together with the fact that many...

  10. Electrodialytic remediation of air pollution control residues in bench scale

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ferreira, Celia; Hansen, Henrik K.;

    2008-01-01

    Air pollution control (APC) residue from municipal solid waste incineration (MSWI) is considered a hazardous waste due to its alkalinity and high content of salts and mobile heavy metals. Various solutions for the handling of APC-residue exist in different regions; however, most commercial....... A system resembling conventional electrodialysis was designed and adjusted to fit the high solids content feed solution (10% APC residue, 90% water). Experiments were made in bench scale with raw residue (natural pH > 12), water pre-residue (natural pH > 12), acid pre-washed residue (pH 10), and acid......-treated residue (pH 2). Our results show that the soluble fraction of the toxic elements Pb, Cu, Cd and Zn was removed from the feed solution and concentrated in the concentrate solution. Furthermore, the leaching (leaching test at L/S 2) of these elements was substantially reduced during treatment (fig. 1...

  11. Electroremediation of air pollution control residues in a continuous reactor

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ferreira, Célia M. D.; Hansen, Henrik K.;

    2010-01-01

    Air pollution control (APC) residue from municipal solid waste incineration is considered hazardous waste due to its alkalinity and high content of salts and mobile heavy metals. Various solutions for the handling of APC-residue exist, however most commercial solutions involve landfilling. A demand...... were made with raw residue, water-washed residue, acid washed residue and acid-treated residue with emphasis on reduction of heavy metal mobility. Main results indicate that the reactor successfully removes toxic elements lead, copper, cadmium and zinc from the feed stream, suggesting...

  12. Characterization of air pollution control residues produced in a municipal solid waste incinerator in Portugal

    OpenAIRE

    Quina, Margarida J.; Santos, Regina C.; Bordado, João C.; Quinta-Ferreira, Rosa M.

    2008-01-01

    This study is mainly related with the physical and chemical characterization of a solid waste, produced in a municipal solid waste (MSW) incineration process, which is usually referred as air pollution control (APC) residue. The moisture content, loss on ignition (LOI), particle size distribution, density, porosity, specific surface area and morphology were the physical properties addressed here. At the chemical level, total elemental content (TC), total availability (TA) and the leaching beh...

  13. On-site treatment and landfilling of MSWI air pollution control residues

    DEFF Research Database (Denmark)

    Lundtorp, Kasper; Jensen, Dorthe Lærke; Sørensen, Mette Abildgaard;

    2003-01-01

    Air pollution control (APC) residues from municipal solid waste incineration (MSWI) are difficult to landfill due to substantial leaching of trace metals. An on-site pretreatment prior to landfilling of APC-residues was investigated in terms of bench-scale experiments with a semidry APC......-residue and a fly ash. The treatment involved mixing of the residues with a ferrous sulphate solution and subsequent oxidation of the suspension. Afterwards, the suspension was spread on a dedicated landfill section and allowed to drain by gravity through the drainage system of the landfill. The wastewater from...

  14. Recycling of air pollution control residues from municipal solid waste incineration into lightweight aggregates.

    Science.gov (United States)

    Quina, Margarida J; Bordado, João M; Quinta-Ferreira, Rosa M

    2014-02-01

    This work focuses on the assessment of technological properties and on the leaching behavior of lightweight aggregates (LWA) produced by incorporating different quantities of air pollution control (APC) residues from municipal solid waste (MSW) incineration. Currently this hazardous waste has been mostly landfilled after stabilization/solidification. The LWA were produced by pelletizing natural clay, APC residues as-received from incineration plant, or after a washing treatment, a small amount of oil and water. The pellets were fired in a laboratory chamber furnace over calcium carbonate. The main technological properties of the LWA were evaluated, mainly concerning morphology, bulk and particle densities, compressive strength, bloating index, water adsorption and porosity. Given that APC residues do not own expansive (bloating) properties, the incorporation into LWA is only possible in moderate quantities, such as 3% as received or 5% after pre-washing treatment. The leaching behavior of heavy metals from sintered LWA using water or acid solutions was investigated, and despite the low acid neutralization capacity of the synthetic aggregates, the released quantities were low over a wide pH range. In conclusion, after a washing pre-treatment and if the percentage of incorporation is low, these residues may be incorporated into LWA. However, the recycling of APC residues from MSW incineration into LWA does not revealed any technical advantage.

  15. Recycling of air pollution control residues from municipal solid waste incineration into lightweight aggregates.

    Science.gov (United States)

    Quina, Margarida J; Bordado, João M; Quinta-Ferreira, Rosa M

    2014-02-01

    This work focuses on the assessment of technological properties and on the leaching behavior of lightweight aggregates (LWA) produced by incorporating different quantities of air pollution control (APC) residues from municipal solid waste (MSW) incineration. Currently this hazardous waste has been mostly landfilled after stabilization/solidification. The LWA were produced by pelletizing natural clay, APC residues as-received from incineration plant, or after a washing treatment, a small amount of oil and water. The pellets were fired in a laboratory chamber furnace over calcium carbonate. The main technological properties of the LWA were evaluated, mainly concerning morphology, bulk and particle densities, compressive strength, bloating index, water adsorption and porosity. Given that APC residues do not own expansive (bloating) properties, the incorporation into LWA is only possible in moderate quantities, such as 3% as received or 5% after pre-washing treatment. The leaching behavior of heavy metals from sintered LWA using water or acid solutions was investigated, and despite the low acid neutralization capacity of the synthetic aggregates, the released quantities were low over a wide pH range. In conclusion, after a washing pre-treatment and if the percentage of incorporation is low, these residues may be incorporated into LWA. However, the recycling of APC residues from MSW incineration into LWA does not revealed any technical advantage. PMID:24238798

  16. Utilization of air pollution control residues for the stabilization/solidification of trace element contaminated soil.

    Science.gov (United States)

    Travar, I; Kihl, A; Kumpiene, J

    2015-12-01

    The aim of this study was to evaluate the stabilization/solidification (S/S) of trace element-contaminated soil using air pollution control residues (APCRs) prior to disposal in landfill sites. Two soil samples (with low and moderate concentrations of organic matter) were stabilized using three APCRs that originated from the incineration of municipal solid waste, bio-fuels and a mixture of coal and crushed olive kernels. Two APCR/soil mixtures were tested: 30% APCR/70% soil and 50% APCR/50% soil. A batch leaching test was used to study immobilization of As and co-occurring metals Cr, Cu, Pb and Zn. Solidification was evaluated by measuring the unconfined compression strength (UCS). Leaching of As was reduced by 39-93% in APCR/soil mixtures and decreased with increased amounts of added APCR. Immobilization of As positively correlated with the amount of Ca in the APCR and negatively with the amount of soil organic matter. According to geochemical modelling, the precipitation of calcium arsenate (Ca3(AsO4)2/4H2O) and incorporation of As in ettringite (Ca6Al2(SO4)3(OH)12 · 26H2O) in soil/APCR mixtures might explain the reduced leaching of As. A negative effect of the treatment was an increased leaching of Cu, Cr and dissolved organic carbon. Solidification of APCR/soil was considerably weakened by soil organic matter. PMID:26233740

  17. Geopolymers prepared from DC plasma treated air pollution control (APC) residues glass: properties and characterisation of the binder phase.

    Science.gov (United States)

    Kourti, Ioanna; Devaraj, Amutha Rani; Bustos, Ana Guerrero; Deegan, David; Boccaccini, Aldo R; Cheeseman, Christopher R

    2011-11-30

    Air pollution control (APC) residues have been blended with glass-forming additives and treated using DC plasma technology to produce a high calcium aluminosilicate glass (APC glass). This has been used to form geopolymer-glass composites that exhibit high strength and density, low porosity, low water absorption, low leaching and high acid resistance. The composites have a microstructure consisting of un-reacted residual APC glass particles imbedded in a complex geopolymer and C-S-H gel binder phase, and behave as particle reinforced composites. The work demonstrates that materials prepared from DC plasma treated APC residues have potential to be used to form high quality pre-cast products.

  18. Electrodialytic remediation of two types of air pollution control residues and their applicability in construction materials

    OpenAIRE

    Magro, Cátia Joana Costa

    2014-01-01

    Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente Perfil de Engenharia de Sistemas Ambientais Air pollution control (APC) residues from municipal solid waste incineration are classified as hazardous waste and disposed of, although it contains potential resources. Due to the different fuel gas cleaning system designs (wet or semi-dry), the APC residues present distinct chemical and physical characteristics that influence the remediation success and their possible reuse. ...

  19. Effects of thermal treatment on mineralogy and heavy metal behavior in iron oxide stabilized air pollution control residues

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Bender-Koch, C.; Starckpoole, M. M.;

    2000-01-01

    Stabilization of air pollution control residues by coprecipitation with ferrous iron and subsequent thermal treatment (at 600 and 900 °C) has been examined as a means to reduce heavy metal leaching and to improve product stability. Changes in mineralogy and metal binding were analyzed using various...... analytical and environmental techniques. Ferrihydrite was formed initially but transformed upon thermal treatment to more stable and crystalline iron oxides (maghemite and hematite). For some metals leaching studies showed more substantial binding after thermal treatment, while other metals either...... volatilized or destabilized with respect to leaching. Pb, in particular, exhibited increased reactivity following the formation of an ordered iron oxide structure at 900 °C. The thermal treatment had a positive effect on Cr release, which was reduced significantly at 900 °C in the presence of organic matter...

  20. Treatment of waste incinerator air-pollution-control residues with FeSO4: Concept and product characterization

    DEFF Research Database (Denmark)

    Lundtorp, Kasper; Jensen, Dorthe Lærke; Sørensen, Mette Abildgaard;

    2002-01-01

    This paper describes a new concept for treatment of air- pollution-control (APC) residues from waste incineration and characterises the wastewater and stabilised residues generated by the process. The process involves mixing of APC-residues with a ferrous sulphate solution and subsequent oxidation...

  1. Production of geopolymers using glass produced from DC plasma treatment of air pollution control (APC) residues.

    Science.gov (United States)

    Kourti, Ioanna; Rani, D Amutha; Deegan, D; Boccaccini, A R; Cheeseman, C R

    2010-04-15

    Air pollution control (APC) residues are the hazardous waste produced from cleaning gaseous emissions at energy-from-waste (EfW) facilities processing municipal solid waste (MSW). APC residues have been blended with glass-forming additives and treated using DC plasma technology to produce a high calcium alumino-silicate glass. This research has investigated the optimisation and properties of geopolymers prepared from this glass. Work has shown that high strength geopolymers can be formed and that the NaOH concentration of the activating solution significantly affects the properties. The broad particle size distribution of the APC residue glass used in these experiments results in a microstructure that contains unreacted glass particles included within a geopolymer binder phase. The high calcium content of APC residues may cause the formation of some amorphous calcium silicate hydrate (C-S-H) gel. A mix prepared with S/L=3.4, Si/Al=2.6 and [NaOH]=6M in the activating solution, produced high strength geopolymers with compressive strengths of approximately 130 MPa. This material had high density (2070 kg/m(3)) and low porosity. The research demonstrates for the first time that glass derived from DC plasma treatment of APC residues can be used to form high strength geopolymer-glass composites that have potential for use in a range of applications.

  2. Properties of sintered glass-ceramics prepared from plasma vitrified air pollution control residues

    Energy Technology Data Exchange (ETDEWEB)

    Roether, J.A.; Daniel, D.J. [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); Amutha Rani, D. [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Deegan, D.E. [Tetronics Ltd., Swindon, Wiltshire SN3 4DE (United Kingdom); Cheeseman, C.R., E-mail: c.cheeseman@imperial.ac.uk [Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Boccaccini, A.R., E-mail: a.boccaccini@imperial.ac.uk [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom)

    2010-01-15

    Air pollution control (APC) residues, obtained from a major UK energy from waste (EfW) plant, processing municipal solid waste, have been blended with silica and alumina and melted using DC plasma arc technology. The glass produced was crushed, milled, uni-axially pressed and sintered at temperatures between 750 and 1150 deg. C, and the glass-ceramics formed were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical properties assessed included Vickers's hardness, flexural strength, Young's modulus and thermal shock resistance. The optimum sintering temperature was found to be 950 deg. C. This produced a glass-ceramic with high density ({approx}2.58 g/cm{sup 3}), minimum water absorption ({approx}2%) and relatively high mechanical strength ({approx}81 {+-} 4 MPa). Thermal shock testing showed that 950 deg. C sintered samples could withstand a 700 deg. C quench in water without micro-cracking. The research demonstrates that glass-ceramics can be readily formed from DC plasma treated APC residues and that these have comparable properties to marble and porcelain. This novel approach represents a technically and commercially viable treatment option for APC residues that allow the beneficial reuse of this problematic waste.

  3. Treatment of waste incinerator air-pollution-control residues with FeSO4: Laboratory investigation of design parameters

    DEFF Research Database (Denmark)

    Jensen, Dorthe Lærke; Christensen, Thomas Højlund; Lundtorp, Kasper

    2002-01-01

    The key design parameters of a new process for treatment of air-pollution-control (APC) residues (the Ferroxprocess) were investigated in the laboratory. The optimisation involved two different APC-residues from actual incinerator plants. The design parameters considered were: amount of iron oxide...... supplied, the liquid-to-solid ratio of the process, the separation of solids and wastewater, the sequence of material mixing, the possibilities of reuse of water, the feasibility of using secondary (brackish) water, and simple means to improve the wastewater quality. The investigation showed......-residues must be optimised for each residue. The overall water use can be limited to a L/S-ratio of 3 l kg–1 including water used for washing of the treated products....

  4. Element composition and mineralogical characterisation of air pollution control residue from UK energy-from-waste facilities

    International Nuclear Information System (INIS)

    Highlights: • 66 elements, including “critical strategic elements” were determined in UK EfW APC residues. • Metal pollutants (Zn, Pb, As, Cd, Cu, Mo, Sb, Sn, Se, Ag and In) are enriched in APC residues. • Metal pollutants were widely associated with fine deposits of highly soluble CaClxOH2−x. • Specific metal (Zn, Pb, Cu)-bearing minerals were also detected in APC residues. - Abstract: Air pollution control (APC) residues from energy-from-waste (EfW) are alkaline (corrosive) and contain high concentrations of metals, such as zinc and lead, and soluble salts, such as chlorides and sulphates. The EPA 3050B-extractable concentrations of 66 elements, including critical elements of strategic importance for advanced electronics and energy technologies, were determined in eight APC residues from six UK EfW facilities. The concentrations of Ag (6–15 mg/kg) and In (1–13 mg/kg), as well as potential pollutants, especially Zn (0.26–0.73 wt.%), Pb (0.05–0.2 wt.%), As, Cd, Cu, Mo, Sb, Sn and Se were found to be enriched in all APC residues compared to average crustal abundances. Results from a combination of scanning electron microscopy with energy dispersive X-ray spectroscopy and also powder X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy give an exceptionally full understanding of the mineralogy of these residues, which is discussed in the context of other results in the literature. The present work has shown that the bulk of the crystalline phases present in the investigated APC residues include Ca-based phases, such as CaClxOH2−x, CaCO3, Ca(OH)2, CaSO4, and CaO, as well as soluble salts, such as NaCl and KCl. Poorly-crystalline aragonite was identified by FTIR. Sulphur appears to have complex redox speciation, presenting as both anhydrite and hannebachite in some UK EfW APC residues. Hazardous elements (Zn and Pb) were widely associated with soluble Ca- and Cl-bearing phases (e.g. CaClxOH2−x and sylvite), as well

  5. Sequestration of flue gas CO₂ by direct gas-solid carbonation of air pollution control system residues.

    Science.gov (United States)

    Tian, Sicong; Jiang, Jianguo

    2012-12-18

    Direct gas-solid carbonation reactions of residues from an air pollution control system (APCr) were conducted using different combinations of simulated flue gas to study the impact on CO₂ sequestration. X-ray diffraction analysis of APCr determined the existence of CaClOH, whose maximum theoretical CO₂ sequestration potential of 58.13 g CO₂/kg APCr was calculated by the reference intensity ratio method. The reaction mechanism obeyed a model of a fast kinetics-controlled process followed by a slow product layer diffusion-controlled process. Temperature is the key factor in direct gas-solid carbonation and had a notable influence on both the carbonation conversion and the CO₂ sequestration rate. The optimal CO₂ sequestrating temperature of 395 °C was easily obtained for APCr using a continuous heating experiment. CO₂ content in the flue gas had a definite influence on the CO₂ sequestration rate of the kinetics-controlled process, but almost no influence on the final carbonation conversion. Typical concentrations of SO₂ in the flue gas could not only accelerate the carbonation reaction rate of the product layer diffusion-controlled process, but also could improve the final carbonation conversion. Maximum carbonation conversions of between 68.6% and 77.1% were achieved in a typical flue gas. Features of rapid CO₂ sequestration rate, strong impurities resistance, and high capture conversion for direct gas-solid carbonation were proved in this study, which presents a theoretical foundation for the applied use of this encouraging technology on carbon capture and storage. PMID:23181908

  6. Element composition and mineralogical characterisation of air pollution control residue from UK energy-from-waste facilities

    Energy Technology Data Exchange (ETDEWEB)

    Bogush, Anna [Centre for Resource Efficiency & the Environment (CREE), Department of Civil, Environmental & Geomatic Engineering (CEGE), University College London UCL, Chadwick Building, Gower Street, London WC1E 6BT (United Kingdom); Stegemann, Julia A., E-mail: j.stegemann@ucl.ac.uk [Centre for Resource Efficiency & the Environment (CREE), Department of Civil, Environmental & Geomatic Engineering (CEGE), University College London UCL, Chadwick Building, Gower Street, London WC1E 6BT (United Kingdom); Wood, Ian [Department of Earth Sciences, University College London UCL, Gower Street, London WC1E 6BT (United Kingdom); Roy, Amitava [J. Bennett Johnston, Sr., Center for Advanced Microstructures & Devices, Louisiana State University, 6980 Jefferson Hwy, Baton Rouge, LA 70806 (United States)

    2015-02-15

    Highlights: • 66 elements, including “critical strategic elements” were determined in UK EfW APC residues. • Metal pollutants (Zn, Pb, As, Cd, Cu, Mo, Sb, Sn, Se, Ag and In) are enriched in APC residues. • Metal pollutants were widely associated with fine deposits of highly soluble CaCl{sub x}OH{sub 2−x}. • Specific metal (Zn, Pb, Cu)-bearing minerals were also detected in APC residues. - Abstract: Air pollution control (APC) residues from energy-from-waste (EfW) are alkaline (corrosive) and contain high concentrations of metals, such as zinc and lead, and soluble salts, such as chlorides and sulphates. The EPA 3050B-extractable concentrations of 66 elements, including critical elements of strategic importance for advanced electronics and energy technologies, were determined in eight APC residues from six UK EfW facilities. The concentrations of Ag (6–15 mg/kg) and In (1–13 mg/kg), as well as potential pollutants, especially Zn (0.26–0.73 wt.%), Pb (0.05–0.2 wt.%), As, Cd, Cu, Mo, Sb, Sn and Se were found to be enriched in all APC residues compared to average crustal abundances. Results from a combination of scanning electron microscopy with energy dispersive X-ray spectroscopy and also powder X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy give an exceptionally full understanding of the mineralogy of these residues, which is discussed in the context of other results in the literature. The present work has shown that the bulk of the crystalline phases present in the investigated APC residues include Ca-based phases, such as CaCl{sub x}OH{sub 2−x}, CaCO{sub 3}, Ca(OH){sub 2}, CaSO{sub 4}, and CaO, as well as soluble salts, such as NaCl and KCl. Poorly-crystalline aragonite was identified by FTIR. Sulphur appears to have complex redox speciation, presenting as both anhydrite and hannebachite in some UK EfW APC residues. Hazardous elements (Zn and Pb) were widely associated with soluble Ca- and Cl-bearing phases

  7. Preliminary investigation of the effect of air-pollution-control residue from waste incineration on the properties of cement paste and mortar

    DEFF Research Database (Denmark)

    Geiker, Mette Rica; Kjeldsen, Ane Mette; Galluci, Emmanuel;

    2006-01-01

    For preliminary assessment of the engineering properties of concrete with air-pollution-control residue from waste incineration (APC) the possible reactivity of APC and the effect of APC on cement hydration were investigated by isothermal calorimetry, chemical shrinkage (pychnometry), thermal...... analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, compressive strength development was measured and impregnated plane sections were prepared. The APC was from a Danish wet process plant. Although the APC contained high amounts of chloride (approx. 10%) and heavy...

  8. Electrodialytic removal of heavy metals and chloride from municipal solid waste incineration fly ash and air pollution control residue in suspension - test of a new two compartment experimental cell

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Magro, Cátia; Guedes, Paula;

    2015-01-01

    Municipal solid waste incineration (MSWI) residues such as fly ash and air pollution control (APC) residues are classified as hazardous waste and disposed of, although they contain potential resources. The most problematic elements in MSWI residues are leachable heavy metals and salts. For reuse ...

  9. The influence of electrodialytic remediation on dioxin (PCDD/PCDF) levels in fly ash and air pollution control residues

    DEFF Research Database (Denmark)

    Dias-Ferreira, Celia; Kirkelund, Gunvor Marie; Jensen, Pernille Erland

    2016-01-01

    dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), and how these levels impact on the valorization options for fly ash and APC residue.PCDD/PCDF levels in the original residues ranged between 4.85 and 197 ng g-1, being higher for the electrostatic precipitator fly ash. The toxic equivalent...... materials dissolve, leaving behind the non-water soluble compounds, such as PCDD/PCDF. According to the Basel Convention, PCDD/PCDF levels in these materials is low (valorized, for instance as construction material, provided end...

  10. Metals accumulations during thermal processing of sewage sludge - characterization of bottom ash and air pollution control (APC) residues

    Science.gov (United States)

    Kasina, Monika; Kowalski, Piotr R.; Michalik, Marek

    2016-04-01

    Due to increasing mass of sewage sludge, problems in its management have appeared. Over years sewage sludge was landfilled, however due to EU directives concerning environmental issues this option is no longer possible. This type of material is considered hazardous due to highly concentrated metals and harmful elements, toxic organic substances and biological components (e.g. parasites, microbes). Currently in Europe, incineration is considered to be the most reasonable method for sewage sludge treatment. As a result of sludge incineration significant amount of energy is recovered due to high calorific value of sewage sludge but bottom ash and APC residues are being produced. In this study we show the preliminary results of chemical and mineral analyses of both bottom ash and APC residues produced in fluidized bed boiler in sewage sludge incineration plant in Poland, with a special emphasis on metals which, as a part of incombustible fraction can accumulate in the residual materials after thermal processing. The bottom ash was a SiO2-P2O5-Fe2O3-CaO-Al2O3 dominated material. Main mineral phases identified in X-ray diffraction patterns were: quartz, feldspar, hematite, and phosphates (apatite and scholzite). The bottom ash was characterized by high content of Zn - 4472 mg kg‑1, Cu - 665.5 mg kg‑1, Pb - 138 mg kg‑1, Ni - 119.5 mg kg‑1, and interestingly high content of Au - 0.858 mg kg‑1 The APC residues composition was dominated by soluble phases which represent more than 90% of the material. The XRD patterns indicated thenardite, halite, anhydrite, calcite and apatite as main mineral phases. The removal of soluble phases by dissolution in deionised water caused a significant mass reduction (ca. 3% of material remained on the filters). Calcite, apatite and quartz were main identified phases. The content of metals in insoluble material is relatively high: Zn - 6326 mg kg‑1, Pb - 514.3 mg kg‑1, Cu - 476.6 mg kg‑1, Ni - 43.3 mg kg‑1. The content of Cd

  11. Effect of drying on leaching testing of treated municipal solid waste incineration APC-residues

    DEFF Research Database (Denmark)

    Hu, Y.; Hyks, Jiri; Astrup, Thomas;

    2008-01-01

    Air-pollution-control (APC) residues from waste incinerators are hazardous waste according to European legislation and must be treated prior to landfilling. Batch and column leaching data determine which type of landfill can receive the treated APC-residues. CEN standards are prescribed...

  12. 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

  13. Air pollution control policy in Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Leutert, G. [Forests and Landscape, Berne (Switzerland). Federal Office of Environment

    1995-12-31

    The legal basis of the Swiss air pollution control policy is set by the Federal Law on the Protection of the Environment, which came into force in 1985. It aims to protect human beings, animals and plants, their biological communities and habitats against harmful effects or nuisances and to maintain the fertility of the soil. The law is source-oriented (by emission standards) as well as effect-oriented (by ambient air quality standards). To link both elements a two-stage approach is applied. In the first stage preventive measures are taken at the emitting sources, irrespective of existing air pollution levels. Emissions have to be limited by early preventive measures as much as technical and operational conditions allow and as far as economically acceptable (prevention principle). By this, air pollution shall be kept as low as possible as a matter of principle, without the environment having to be in danger first. In a second stage the measures are strengthened or backed up by additional measures if ambient air quality standards laid down in the Ordinance on Air Pollution Control are exceeded. At this second stage, protection of man and his environment has priority over economic considerations. (author)

  14. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.;

    2011-01-01

    with geochemical modelling were carried out both on fresh and aged samples. The results showed that the material is comparable to residues from wood combustion and the leaching behaviour was dominated by Ca-containing minerals and solid solutions. Heavy metals were detected in very low concentrations in the bulk......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...

  15. 75 FR 56889 - Revisions to the California State Implementation Plan, San Diego County Air Pollution Control...

    Science.gov (United States)

    2010-09-17

    ...: EPA is taking direct final action to approve revisions to the San Diego County Air Pollution Control... Environmental protection, Air pollution control, Incorporation by reference, Intergovernmental relations.... * * * * * (c) * * * (379) * * * (i) * * * (B) San Diego County Air Pollution Control District. (1) Rule...

  16. Leaching characteristics of calcium-based compounds in MSWI Residues: From the viewpoint of clogging risk

    International Nuclear Information System (INIS)

    Highlights: • The leaching behavior of Ca-based compounds commonly in MSWI residues was studied. • pH is the crucial factor for calcium leaching process. • CaCO3 was the most sensitive to leaching temperature and Ca3(PO4)2 was the least. • Ca leaching of MSWIBA and SAPCR attributed to CaCO3 and Ca3(PO4)2 respectively. • Potential clogging ability of MSWI residues leachate in open air was calculated. - Abstract: Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO3 and CaSiO3 began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca3(PO4)2 leached at pH < 12. CaSO4 could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO3 > Ca3(PO4)2 > CaCO3. The calcium leaching from the MSWIBA and SAPCR separately started from pH < 7 and pH < 12, resulting from CaCO3 and Ca3(PO4)2 leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the theoretical basis for the risk assessment pertaining to LCS clogging in landfills

  17. Leaching characteristics of calcium-based compounds in MSWI Residues: From the viewpoint of clogging risk

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yi [State Key Laboratory of Pollution Control & Resource Reuse, Tongji University, Shanghai 200092 (China); Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Zhang, Hua, E-mail: zhanghua_tj@tongji.edu.cn [State Key Laboratory of Pollution Control & Resource Reuse, Tongji University, Shanghai 200092 (China); Phoungthong, Khamphe [State Key Laboratory of Pollution Control & Resource Reuse, Tongji University, Shanghai 200092 (China); Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Shi, Dong-Xiao; Shen, Wen-Hui [Changzhou Domestic Waste Treatment Center, Changzhou 213000 (China); Shao, Li-Ming [Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Center for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban–Rural Development of PR China (MOHURD), Shanghai 200092 (China); He, Pin-Jing, E-mail: solidwaste@tongji.edu.cn [Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Center for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban–Rural Development of PR China (MOHURD), Shanghai 200092 (China)

    2015-08-15

    Highlights: • The leaching behavior of Ca-based compounds commonly in MSWI residues was studied. • pH is the crucial factor for calcium leaching process. • CaCO{sub 3} was the most sensitive to leaching temperature and Ca{sub 3}(PO{sub 4}){sub 2} was the least. • Ca leaching of MSWIBA and SAPCR attributed to CaCO{sub 3} and Ca{sub 3}(PO{sub 4}){sub 2} respectively. • Potential clogging ability of MSWI residues leachate in open air was calculated. - Abstract: Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO{sub 3} and CaSiO{sub 3} began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca{sub 3}(PO{sub 4}){sub 2} leached at pH < 12. CaSO{sub 4} could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO{sub 3} > Ca{sub 3}(PO{sub 4}){sub 2} > CaCO{sub 3}. The calcium leaching from the MSWIBA and SAPCR separately started from pH < 7 and pH < 12, resulting from CaCO{sub 3} and Ca{sub 3}(PO{sub 4}){sub 2} leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the

  18. Air Pollution Control in Municipal Solid Waste Incinerators

    OpenAIRE

    Quina, Margarida J.; Bordado, João C.M.; Quinta-Ferreira, Rosa M.

    2011-01-01

    Municipal solid waste (MSW) remains a major problem in modern societies, even though the significant efforts to prevent, reduce, reuse and recycle. At present, municipal solid waste incineration (MSWI) in waste-to-energy (WtE) plants is one of the main management options in most of the developed countries. The technology for recovering energy from MSW has evolved over the years and now sophisticated air pollution control (APC) equipment insures that emissions comply with the st...

  19. 76 FR 31242 - Revisions to the California State Implementation Plan, Santa Barbara County Air Pollution Control...

    Science.gov (United States)

    2011-05-31

    ... Environmental protection, Air pollution control, Incorporation by reference, Intergovernmental relations... Identification of plan. * * * * * (c) * * * (359) * * * (i) * * * (E) Santa Barbara County Air Pollution Control... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Santa Barbara County...

  20. 75 FR 24544 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control...

    Science.gov (United States)

    2010-05-05

    ... Control District, Sacramento Metropolitan Air Quality Management District, San Joaquin Valley Unified Air Pollution Control District, and South Coast Air Quality Management District AGENCY: Environmental Protection... Air Pollution Control District (PCAPCD), Sacramento Metropolitan Air Quality Management...

  1. Air classification: Potential treatment method for optimized recycling or utilization of fine-grained air pollution control residues obtained from dry off-gas cleaning high-temperature processing systems.

    Science.gov (United States)

    Lanzerstorfer, Christof

    2015-11-01

    In the dust collected from the off-gas of high-temperature processes, usually components that are volatile at the process temperature are enriched. In the recycling of the dust, the concentration of these volatile components is frequently limited to avoid operation problems. Also, for external utilization the concentration of such volatile components, especially heavy metals, is often restricted. The concentration of the volatile components is usually higher in the fine fractions of the collected dust. Therefore, air classification is a potential treatment method to deplete the coarse material from these volatile components by splitting off a fines fraction with an increased concentration of those volatile components. In this work, the procedure of a sequential classification using a laboratory air classifier and the calculations required for the evaluation of air classification for a certain application were demonstrated by taking the example of a fly ash sample from a biomass combustion plant. In the investigated example, the Pb content in the coarse fraction could be reduced to 60% by separation of 20% fines. For the non-volatile Mg the content was almost constant. It can be concluded that air classification is an appropriate method for the treatment of off-gas cleaning residues. PMID:26268600

  2. Market Report : The air pollution control market in Argentina

    International Nuclear Information System (INIS)

    This report presents some facts about how Canadian companies can work within the many innovative programs designed by the Canadian federal government to facilitate the export of Canadian products and services into the Argentine air pollution control market. As the economy stabilizes in Argentina, more effort is being given to issues of environmental protection and the Argentine government is increasing funding on environmental programs. The country is also strengthening its environmental legislation and increasing enforcement. The Kyoto and Montreal Protocols have brought attention to air quality issues such as climate change, emissions trading, and ozone depleting substances. Several initiatives currently focus on air quality monitoring and data collection since much information has to be gathered on air pollution levels. Emission control equipment for chemical, petrochemical, mining and power sectors are the best prospects for air pollution control, along with monitoring equipment, consulting services and fuel conversion equipment for vehicles and industrial plants. It was noted that there are legal and practical difficulties regarding new contract negotiations in Argentina, particularly with the decline in credit availability. This paper outlined the key factors shaping market growth. Most opportunities lies with projects funded by international financial institutions. The report includes a section on international competition, and the Canadian position for both private- and public-sector companies. A section on market logistics focused on issues such as direct sales, import regulations, and export credit risks. It is recommended that companies interested in the Argentine market contact the Embassy in Buenos Aires for information. refs., tabs

  3. Increasing silver leaching rate from leaching-resistant zinc residues by thiourea leaching method with pressurized preoxidation process

    Institute of Scientific and Technical Information of China (English)

    胡天觉; 曾光明; 黄国和; 袁兴中; 李建兵

    2003-01-01

    As for the leaching-resistant zinc residues, the silver leaching rate can be over 98% through the processof pressurized preoxidation and thiourea leaching. Compared with the method of extracting the silver directly fromthe leaching-resistant zinc residues, the silver leaching rate is greatly improved. The optimum preoxidation condi-tions are: particle size range 40 - 60 μm, oxygen partial pressure 106 Pa, temperature 80 - 90 ℃, pH= 1.0, andleaching time 5 h. After pretreatment, the time of thiourea leaching silver is shortened to 1.5 h, and the thioureaconsumption is reduced greatly. The oxidation mechanism and the thiourea leaching kinetics were also explored.

  4. 77 FR 73392 - Revisions to the California State Implementation Plan, Monterey Bay Unified Air Pollution Control...

    Science.gov (United States)

    2012-12-10

    ... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Monterey Bay Unified Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is proposing to approve revisions to the Monterey Bay Unified Air Pollution Control...

  5. 75 FR 56942 - Revisions to the California State Implementation Plan, San Diego County Air Pollution Control...

    Science.gov (United States)

    2010-09-17

    ... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, San Diego County Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is proposing to approve revisions to the San Diego Air Pollution Control District...

  6. 75 FR 45082 - Revisions to the California State Implementation Plan, Santa Barbara County Air Pollution Control...

    Science.gov (United States)

    2010-08-02

    ... Air Pollution Control District (SBCAPCD) portion of the California State Implementation Plan (SIP... Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990'', 57 FR 13498, April 16... Environmental protection, Air pollution control, Intergovernmental relations, Nitrogen dioxide, Ozone,...

  7. 76 FR 298 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Science.gov (United States)

    2011-01-04

    ... Valley Unified Air Pollution Control District (SJVUAPCD) portion of the California State Implementation......... 12/17/92 08/24/07 On September 17, 2007, the submittal for San Joaquin Valley Unified Air Pollution... require that fixed covers be equipped with a 95% efficient Air Pollution Control (APC) device. c....

  8. Landfilling of waste incineration residues

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Cai, Zuansi;

    2002-01-01

    Residues from waste incineration are bottom ashes and air-pollution-control (APC) residues including fly ashes. The leaching of heavy metals and salts from the ashes is substantial and a wide spectrum of leaching tests and corresponding criteria have been introduced to regulate the landfilling...... of the ashes. Leaching test, however, must be selected carefully to provide information relevant for the actual disposal scenario and for evaluating the benefits of pre-treating the residues prior to landfilling. This paper describes research at the Technical University of Denmark addressing some...

  9. Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

    Science.gov (United States)

    Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

  10. Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

    Science.gov (United States)

    Wang, Le; Mu, Wen-ning; Shen, Hong-tao; Liu, Shao-ming; Zhai, Yu-chun

    2015-05-01

    A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaCl2 aqueous solution, liquid-to-solid (L/S) ratio, leaching temperature, and leaching time, were investigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaCl2 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7:1, a leaching temperature of 80°C, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

  11. Effect of municipal solid waste incinerator types on characteristics of ashes from different air pollution control devices.

    Science.gov (United States)

    Lu, Chien-Hsing; Chuang, Kui-Hao

    2016-01-01

    The purpose of this paper is to investigate the characteristics of fly and bottom ashes sampled from both fluidized bed (FB) and mass-burning (MB) municipal solid waste incinerators (MSWIs), respectively. Fly ashes from different locations at FB and MB MSWIs equipped with a cyclone, a semi-dry scrubber, and a bag filter as air pollution control devices were examined to provide the baseline information between physicochemical properties and leaching ability. Experimental results of leachability indicated that the bag filter fly ash (FB-FA(B)) from the FB incinerator meets Taiwan regulatory standards set through the toxicity characteristic leaching procedure. X-ray diffraction results revealed the presence of Cr5O12 and Pb2O3 in the cyclone fly ash (MB-FA(C)) and bag filter fly ash (MB-FA(B)), respectively, from the MB incinerator. To observe lead incorporation mechanism, mixture of simulate lead-laden waste with bed material were fired between 600 °C and 900 °C in a laboratory scale FB reactor. The results clearly demonstrate a substantial decrease in lead leaching ratio for products with an appropriate temperature. The concentration of Pb in the MB-FA(B) was 250 times that in the FB-FA(B), suggesting that incineration of MSW in FB is a good strategy for stabilizing hazardous metals.

  12. Effect of municipal solid waste incinerator types on characteristics of ashes from different air pollution control devices.

    Science.gov (United States)

    Lu, Chien-Hsing; Chuang, Kui-Hao

    2016-01-01

    The purpose of this paper is to investigate the characteristics of fly and bottom ashes sampled from both fluidized bed (FB) and mass-burning (MB) municipal solid waste incinerators (MSWIs), respectively. Fly ashes from different locations at FB and MB MSWIs equipped with a cyclone, a semi-dry scrubber, and a bag filter as air pollution control devices were examined to provide the baseline information between physicochemical properties and leaching ability. Experimental results of leachability indicated that the bag filter fly ash (FB-FA(B)) from the FB incinerator meets Taiwan regulatory standards set through the toxicity characteristic leaching procedure. X-ray diffraction results revealed the presence of Cr5O12 and Pb2O3 in the cyclone fly ash (MB-FA(C)) and bag filter fly ash (MB-FA(B)), respectively, from the MB incinerator. To observe lead incorporation mechanism, mixture of simulate lead-laden waste with bed material were fired between 600 °C and 900 °C in a laboratory scale FB reactor. The results clearly demonstrate a substantial decrease in lead leaching ratio for products with an appropriate temperature. The concentration of Pb in the MB-FA(B) was 250 times that in the FB-FA(B), suggesting that incineration of MSW in FB is a good strategy for stabilizing hazardous metals. PMID:26226945

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

    OpenAIRE

    Yao J.H.; Li X.H.; Li Y.W.

    2011-01-01

    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...

  14. 40 CFR 63.13 - Addresses of State air pollution control agencies and EPA Regional Offices.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Addresses of State air pollution... POLLUTANTS FOR SOURCE CATEGORIES General Provisions § 63.13 Addresses of State air pollution control agencies... Wynkoop Street, Denver, CO 80202-1129. EPA Region IX (Arizona, California, Hawaii, Nevada, American...

  15. APEX (Air Pollution Exercise) Volume 21: Legal References: Air Pollution Control Regulations.

    Science.gov (United States)

    Environmental Protection Agency, Research Triangle Park, NC. Office of Manpower Development.

    The Legal References: Air Pollution Control Regulations Manual is the last in a set of 21 manuals (AA 001 009-001 029) used in APEX (Air Pollution Exercise), a computerized college and professional level "real world" game simulation of a community with urban and rural problems, industrial activities, and air pollution difficulties. The manual…

  16. 77 FR 73322 - Revisions to the California State Implementation Plan, Monterey Bay Unified Air Pollution Control...

    Science.gov (United States)

    2012-12-10

    ...: EPA is taking direct final action to approve revisions to the Monterey Bay Unified Air Pollution... Part 52 Environmental protection, Air pollution control, Incorporation by reference, Intergovernmental... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Monterey Bay Unified...

  17. Implementation by environmental administration of the Finnish air pollution control act

    Energy Technology Data Exchange (ETDEWEB)

    Haapaniemi, J. [Turku Univ. (Finland). Dept. of Political Science

    1995-12-31

    The aim of this research is to show how the general wording of the Air Pollution Control Act which came into force in 1982 has been given practical meanings. The main interest is the administrational implementation of the aims of the air pollution legislation for regulation of industrial activities and the energy sector. The article focuses on the decisions and the decision-making process through the Air Pollution Control Act with its relatively flexible norms. It gives a view of air pollution control practices and its problems, especially concerning sulphur emissions of whose control there is already lot of experiences. The grounds for resolutions given according to the Air Pollution Control Act and the possibility of public participation in their making are the centre of attention here. The greatest interest is cases on the decisions made by applying general governmental decisions, especially regulations concerning coal-fired power plants, and the regulations for sulphur dioxide emissions, in the governmental decision of 1987. (author)

  18. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    International Nuclear Information System (INIS)

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  19. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Butera, S. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Kosson, D.S. [Vanderbilt University, Department of Civil and Environmental Engineering, Box 1831 Station B, Nashville, TN 37235 (United States); Van Zomeren, A. [Energy Research Centre of the Netherlands (ECN), Department of Environmental Risk Assessment, P.O. Box 1, 1755 ZG Petten (Netherlands); Van der Sloot, H.A. [Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk (Netherlands); Astrup, T.F. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark)

    2015-04-15

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  20. 40 CFR 424.40 - Applicability; description of the covered calcium carbide furnaces with wet air pollution control...

    Science.gov (United States)

    2010-07-01

    ... covered calcium carbide furnaces with wet air pollution control devices subcategory. 424.40 Section 424.40... FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Covered Calcium Carbide Furnaces With Wet Air Pollution Control Devices Subcategory § 424.40 Applicability; description of the covered calcium carbide...

  1. Mechanical Activation-Assisted Reductive Leaching of Cadmium from Zinc Neutral Leaching Residue Using Sulfur Dioxide

    Science.gov (United States)

    Zhang, Chun; Min, Xiaobo; Chai, Liyuan; Zhang, Jianqiang; Wang, Mi

    2015-12-01

    In this work, zinc neutral leaching residue was mechanically activated by ball-milling. The subsequent leaching behavior and kinetics of cadmium extraction in a mixed SO2-H2SO4 system were studied. Changes in the crystalline phase, lattice distortion, particle size and morphology, which were induced by mechanical activation, were also investigated. The activated samples showed different physicochemical characteristics, and cadmium extraction was found to be easier than for the un-activated samples. Under the same conditions, mechanical activation contributed to higher cadmium leaching. The cadmium extraction kinetics at 75-95°C was found to fit the shrinking core model. The raw neutral leaching residue, and the samples activated for 60 min and 120 min had a calculated activation energy of 65.02 kJ/mol, 59.45 kJ/mol and 53.46 kJ/mol, respectively. The leaching residue was characterized by ICP, XRD and SEM analysis. According to XRD analysis, the main phases in the residue were lead sulfate (PbSO4), zinc sulfide (ZnS) and cadmium sulfide (CdS).

  2. 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.

  3. The application of active noise control technology to reduce noise from air pollution control equipment

    Energy Technology Data Exchange (ETDEWEB)

    Depies, C. R.; Kapsos, D. W.

    1996-08-01

    The basic concept of active noise control, i. e. to create a noise field in a space in order to destructively interfere with an existing noise, and in the process create a quieter space, was explained. The manner in which noise control technology can be used in air pollution control equipment was described and guidelines for application were provided. A number of case studies were used to illustrate the suitability of active noise control for low frequency noise problems, especially in the area of air pollution control equipment. Impressive reduction of low frequency noise, energy efficiency, ability to retrofit into an existing duct system, and the hardware`s insensitivity to dirty exhaust environments were cited as the principal reasons for the success of active noise control technology over more traditional in-line passive silencers. 1 ref., 8 figs.

  4. Study on leaching vanadium from roasted residue of stone coal

    Energy Technology Data Exchange (ETDEWEB)

    He, D.; Feng, Q.; Zhang, G.; Luo, W.; Ou, L. [Central South University, Changsha (China)

    2008-11-15

    In China, the total reserves of vanadium, reported as V{sub 2}O{sub 5}, in stone coal is 118 Mt (130 million st). Recovering vanadium from such a large resource is very important to China's vanadium industry. The technology now being used to recover vanadium from stone coal has the following two problems in the leaching process: a low recovery of vanadium and high acid consumption. To resolve these problems, a new leaching technology is proposed. The effects of factors such as H{sub 2}SO{sub 4} concentration, liquid-solid ratio, temperature and time, and the types and additions of additives were studied. By adding 1.5% (by weight) CaF2 and leaching the roasted residue of stone coal with 5.4% (by weight) sulfuric acid at 90{sup o}C for 12 hours at a liquid-solid ratio of 2 mL/g, the leaching degree of vanadium reached 83.10%. This proposed leaching technology gives a feasible alternative for the processing of roasting residue of stone coal and can be applied in the comprehensive utilization of stone coal ores in China.

  5. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Butera, Stefania; Kosson, D.S.;

    2015-01-01

    , due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system......Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis...... of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens...

  6. Air pollution control system research: An iterative approach to developing affordable systems

    Science.gov (United States)

    Watt, Lewis C.; Cannon, Fred S.; Heinsohn, Robert J.; Spaeder, Timothy A.

    1995-01-01

    This paper describes a Strategic Environmental Research and Development Program (SERDP) funded project led jointly by the Marine Corps Multi-Commodity Maintenance Centers, and the Air and Energy Engineering Research Laboratory (AEERL) of the USEPA. The research focuses on paint booth exhaust minimization using recirculation, and on volatile organic compound (VOC) oxidation by the modules of a hybrid air pollution control system. The research team is applying bench, pilot and full scale systems to accomplish the goals of reduced cost and improved effectiveness of air treatment systems for paint booth exhaust.

  7. Air pollution control systems and technologies for waste-to-energy facilities

    International Nuclear Information System (INIS)

    One of the primary topics of concern to those planning, developing, and operating waste-to-energy (W-T-E) [also known as municipal waste combustors (MWCs)] facilities is air emissions. This paper presents a description of the state-of-the-art air pollution control (APC) systems and technology for particulate, heavy metals, organics, and acid gases control for W-T-E facilities. Items covered include regulations, guidelines, and control techniques as applied in the W-T-E industry. Available APC technologies are viewed in detail on the basis of their potential removal efficiencies, design considerations, operations, and maintenance costs

  8. Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

    Science.gov (United States)

    Gong, J. C.; Zhu, T.; Hu, M.; Zhang, L. W.; Cheng, H.; Zhang, L.; Tong, J.; Zhang, J.

    2010-08-01

    Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein) in a central Beijing site in the summer and early fall of 2008 (from June to October). Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's air quality during the Olympics had any impact on concentrations of the three aldehydes. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.34 ± 15.12 μg/m3, 27.09 ± 15.74 μg/m3 and 2.32 ± 0.95 μg/m3, respectively, for the entire period of measurements, all being the highest among the levels measured in cities around the world in photochemical smog seasons. Among the three measured aldehydes, only acetaldehyde had a substantially reduced mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Formaldehyde and acrolein followed the changing pattern of temperature and were each significantly correlated with ozone (a secondary product of photochemical reactions). In contrast, acetaldehyde was significantly correlated with several pollutants emitted mainly from local emission sources (e.g., NO2, CO, and PM2.5). These findings suggest that local direct emissions had a larger impact on acetaldehyde than formaldehyde and acrolein.

  9. Portable air pollution control equipment for the control of toxic particulate emissions

    Energy Technology Data Exchange (ETDEWEB)

    Chaurushia, A.; Odabashian, S.; Busch, E. [Northrop Grumman Corp., El Segundo, CA (United States). Military Aircraft Systems Div.

    1997-12-31

    Chromium VI (Cr VI) has been identified by the environmental regulatory agencies as a potent carcinogen among eleven heavy metals. A threshold level of 0.0001 lb/year for Cr VI emissions has been established by the California Air Resources Board for reporting under Assembly Bill 2588. A need for an innovative control technology to reduce fugitive emissions of Cr VI was identified during the Air Toxic Emissions Reduction Program at Northrop Grumman Military Aircraft Systems Division (NGMASD). NGMASD operates an aircraft assembly facility in El Segundo, CA. Nearly all of the aircraft components are coated with a protective coating (primer) prior to assembly. The primer has Cr VI as a component for its excellent corrosion resistance property. The complex assembly process requires fasteners which also need primer coating. Therefore, NGMASD utilizes High Volume Low Pressure (HVLP) guns for the touch-up spray coating operations. During the touch-up spray coating operations, Cr VI particles are atomized and transferred to the aircraft surface. The South Coast Air Quality Management District (SCAQMD) has determined that the HVLP gun transfers 65% of the paint particles onto the substrate and the remaining 35% are emitted as an overspray if air pollution controls are not applied. NGMASD has developed the Portable Air Pollution Control Equipment (PAPCE) to capture and control the overspray in order to reduce fugitive Cr VI emissions from the touch-up spray coating operations. A source test was performed per SCAQMD guidelines and the final report has been approved by the SCAQMD.

  10. Air pollution control system testing at the DOE offgas components test facility

    International Nuclear Information System (INIS)

    In 1997, the Department of Energy (DOE) Savannah River Site (SRS) plans to begin operation of the Consolidated Incineration Facility (CIF) to treat solid and liquid RCRA hazardous and mixed wastes. The Savannah River Technology Center (SRTC) leads an extensive technical support program designed to obtain incinerator and air pollution control equipment performance data to support facility start-up and operation. A key component of this technical support program includes the Offgas Components Test Facility (OCTF), a pilot-scale offgas system test bed. The primary goal for this test facility is to demonstrate and evaluate the performance of the planned CIF Air Pollution Control System (APCS). To accomplish this task, the OCTF has been equipped with a 1/10 scale CIF offgas system equipment components and instrumentation. In addition, the OCTF design maximizes the flexibility of APCS operation and facility instrumentation and sampling capabilities permit accurate characterization of all process streams throughout the facility. This allows APCS equipment performance to be evaluated in an integrated system under a wide range of possible operating conditions. This paper summarizes the use of this DOE test facility to successfully demonstrate APCS operability and maintainability, evaluate and optimize equipment and instrument performance, and provide direct CIF start-up support. These types of facilities are needed to permit resolution of technical issues associated with design and operation of systems that treat and dispose combustible hazardous, mixed, and low-level radioactive waste throughout and DOE complex

  11. Assessment of Air-Pollution Control Policy’s Impact on China’s PV Power: A System Dynamics Analysis

    Directory of Open Access Journals (Sweden)

    Xiaodan Guo

    2016-05-01

    Full Text Available Recently, China has brought out several air-pollution control policies, which indicate the prominent position that PV power hold in improving atmosphere environment. Under this policy environment, the development of China’s PV power will be greatly affected. Firstly, after analyzing the influencing path of air-pollution control policies on PV power, this paper built a system dynamics model, which can be used as a platform for predicting China’s PV power development in every policy scenario during 2015–2025. Secondly, different model parameters are put into the SD model to simulate three scenarios of air-pollution control policies. Comparisons between the simulated results of different policy scenarios measure the air-pollution control policy’s impact on China’s PV power in the aspect of generation, installed capacity, power curtailment and so on. This paper points out the long-term development pattern of China’s PV power under latest incentive policies, and provides reference for the policymakers to increase the effect and efficiency of air-pollution control policies.

  12. Removal efficiencies of PCDDs/PCDFs by air pollution control devices in municipal solid waste incinerators.

    Science.gov (United States)

    Kim, S C; Jeon, S H; Jung, I R; Kim, K H; Kwon, M H; Kim, J H; Yi, J H; Kim, S J; You, J C; Jung, D H

    2001-01-01

    Removal efficiencies of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) by air pollution control devices (APCDs) in the commercial-scale municipal solid waste (MSW) incinerators with a capacity of above 200 ton/day were evaluated. The removal efficiencies of PCDDs/PCDFs were up to 95% when the activated carbon (AC) was injected in front of electrostatic precipitator (EP). Spray dryer absorber/bag filter (SDA/BF) had high removal efficiency (99%)) of PCDDs/PCDFs when a mixture of lime and AC was sprayed into the SDA. When the AC was not added in scrubbing solution, the whole congeners of PCDDs/PCDFs were enriched in the wet scrubber (WS) with negative removal efficiencies of -25% to -5731%. Discharge of PCDDs/PCDFs was decreased with increasing the proportions of AC added in scrubbing solution. Selective catalytic reduction (SCR) system had the removal efficiencies of up to 93% during the test operation.

  13. Air pollution control and decreasing new particle formation lead to strong climate warming

    Directory of Open Access Journals (Sweden)

    R. Makkonen

    2011-09-01

    Full Text Available The number of cloud droplets determines several climatically relevant cloud properties. A major cause for the high uncertainty in the indirect aerosol forcing is the availability of cloud condensation nuclei (CCN, which in turn is highly sensitive to atmospheric new particle formation. Here we present the effect of new particle formation on anthropogenic aerosol forcing in present-day (year 2000 and future (year 2100 conditions. The total aerosol forcing (−1.61 W m−2 in year 2000 is simulated to be greatly reduced in the future, to −0.23 W m−2, mainly due to decrease in SO2 emissions and resulting decrease in new particle formation. With the total aerosol forcing decreasing in response to air pollution control measures taking effect, warming from increased greenhouse gas concentrations can potentially increase at a very rapid rate.

  14. A Framework of Environmental Modelling and Information Sharing for Urban Air Pollution Control and Management

    Institute of Scientific and Technical Information of China (English)

    LIU Gang-jun; FU Er-jiang; WANG Yun-jia; ZHANG Ke-fei; HAN Bao-ping; ARROWSMITH Colin

    2007-01-01

    More effective environmental pollution control and management are needed due to the increasing environmental impacts from a range of human activities and the growing public demands for a better living environment. Urban air pollution is a serious environmental issue that poses adverse impacts on the health of people and the environment in most metropolitan areas. In this paper, we propose a geoinformatics augmented framework of environmental modelling and information sharing for supporting effective urban air pollution control and management. This framework is outlined in terms of its key components and processes including: 1) an integrated, adaptive network of sensors for environmental monitoring; 2) a set of distributed, interoperable databases for data management; 3) a set of intelligent, robust algorithms and models for environmental modelling; 4) a set of flexible, efficient user interfaces for data access and information sharing; and 5) a reliable, high capacity, high performance computing and communication infrastructure for integrating and supporting other framework components and processes.

  15. Air pollution control systems in WtE units: an overview.

    Science.gov (United States)

    Vehlow, J

    2015-03-01

    All WtE (waste-to-energy) plants, based on combustion or other thermal processes, need an efficient gas cleaning for compliance with legislative air emission standards. The development of gas cleaning technologies started along with environment protection regulations in the late 1960s. Modern APC (air pollution control) systems comprise multiple stages for the removal of fly ashes, inorganic and organic gases, heavy metals, and dioxins from the flue gas. The main technologies and devices used for abatement of the various pollutants are described and their basic principles, their peculiarities, and their application are discussed. Few systems for cleaning of synthesis gas from waste gasification plants are included. Examples of APC designs in full scale plants are shown and cautious prospects for the future development of APC systems are made. PMID:25022549

  16. Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

    Directory of Open Access Journals (Sweden)

    J. C. Gong

    2010-08-01

    Full Text Available Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein in a central Beijing site in the summer and early fall of 2008 (from June to October. Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's air quality during the Olympics had any impact on concentrations of the three aldehydes. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.34 ± 15.12 μg/m3, 27.09 ± 15.74 μg/m3 and 2.32 ± 0.95 μg/m3, respectively, for the entire period of measurements, all being the highest among the levels measured in cities around the world in photochemical smog seasons. Among the three measured aldehydes, only acetaldehyde had a substantially reduced mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Formaldehyde and acrolein followed the changing pattern of temperature and were each significantly correlated with ozone (a secondary product of photochemical reactions. In contrast, acetaldehyde was significantly correlated with several pollutants emitted mainly from local emission sources (e.g., NO2, CO, and PM2.5. These findings suggest that local direct emissions had a larger impact on acetaldehyde than formaldehyde and acrolein.

  17. Testing cleanable/reuseable HEPA prefilters for mixed waste incinerator air pollution control systems

    Energy Technology Data Exchange (ETDEWEB)

    Burns, D.B.; Wong, A.; Walker, B.W.; Paul, J.D. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1997-08-01

    The Consolidated Incineration Facility (CIF) at the US DOE Savannah River Site is undergoing preoperational testing. The CIF is designed to treat solid and liquid RCRA hazardous and mixed wastes from site operations and clean-up activities. The technologies selected for use in the air pollution control system (APCS) were based on reviews of existing incinerators, air pollution control experience, and recommendations from consultants. This approach resulted in a facility design using experience from other operating hazardous/radioactive incinerators. In order to study the CIF APCS prior to operation, a 1/10 scale pilot facility, the Offgas Components Test Facility (OCTF), was constructed and has been in operation since late 1994. Its mission is to demonstrate the design integrity of the CIF APCS and optimize equipment/instrument performance of the full scale production facility. Operation of the pilot facility has provided long-term performance data of integrated systems and critical facility components. This has reduced facility startup problems and helped ensure compliance with facility performance requirements. Technical support programs assist in assuring all stakeholders the CIF can properly treat combustible hazardous, mixed, and low-level radioactive wastes. High Efficiency Particulate Air (HEPA) filters are used to remove hazardous and radioactive particulates from the exhaust gas strewn before being released into the atmosphere. The HEPA filter change-out frequency has been a potential issue and was the first technical issue to be studied at the OCTF. Tests were conducted to evaluate the performance of HEPA filters under different operating conditions. These tests included evaluating the impact on HEPA life of scrubber operating parameters and the type of HEPA prefilter used. This pilot-scale testing demonstrated satisfactory HEPA filter life when using cleanable metal prefilters and high flows of steam and water in the offgas scrubber. 8 figs., 2 tabs.

  18. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Jansson, S.;

    2014-01-01

    The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed...... of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits. © 2014 Elsevier B.V....

  19. Study of radionuclide leaching from the residues of K Basin sludge dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, D.B.

    1998-07-30

    The sludges remaining in the K Basins after removal of the spent N Reactor nuclear fuel will be conditioned for disposal. After conditioning, an acid-insoluble residue will remain that may require further leaching to properly condition it for disposal. This document presents a literature study to identify and recommend one or more chemical leaching treatments for laboratory testing, based on the likely compositions of the residues. The processes identified are a nitric acid cerate leach, a silver-catalyzed persulfate leach, a nitric hydrofluoric acid leach, an oxalic citric acid reactor decontamination leach, a nitric hydrochloric acid leach, a ammonium fluoride nitrate leach, and a HEOPA formate dehydesulfoxylate leach. All processes except the last two are recommended for testing in that order.

  20. Electrodialytic upgrading of three different municipal solid waste incineration residue types with focus on Cr, Pb, Zn, Mn, Mo, Sb, Se, V, Cl and SO4

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Kirkelund, Gunvor Marie; Pedersen, Kristine B.;

    2015-01-01

    Handling of air pollution control (APC) residues from municipal solid waste incineration (MSWI) is a challenge due to its toxicity and high leaching of toxic elements and salts. Electrodialysis (ED) of the material has shown potential for reduction of leaching of toxic elements and salts to produce...... systems, as well as MSWI fly ash without flue-gas cleaning products are reported. Significant leaching reduction of the critical elements Pb, Zn and Cl was obtained. The final leaching, however, depended mostly on the initial leaching, thus as leaching from fly ash and residue of wet flue-gas cleaning...... was lower before treatment compared to residues from semidry flue-gas cleaning, both Pb and Zn leaching could be reduced to lower levels in those materials, and they therefore appear more suitable for use in construction materials. The leaching reduction of Zn and to some degree Pb decreased with longer...

  1. Nitrogen oxide air pollution: control technology. 1978-August, 1980 (citations from the NTIS data base). Report for 1978-August 1980

    Energy Technology Data Exchange (ETDEWEB)

    Cavagnaro, D.M.

    1980-10-01

    Nitrogen oxide air pollution control is considered from both mobile and stationary sources. Fluidized bed combustion, boiler combustion modification, and engine design are discussed, as they relate to emissions reduction. (This updated bibliography contains citations, 76 of which are new entries to the previous edition.)

  2. Assessment of long-term pH developments in leachate from waste incineration residues

    DEFF Research Database (Denmark)

    Astrup, Thomas; Jakobsen, Rasmus; Christensen, Thomas Højlund;

    2006-01-01

    influenced by changes in pH over time. The paper presents an approach for assessing pH changes in leachate from municipal solid waste incineration (MSWI) air-pollution-control (APC) residues. Residue samples were subjected to a stepwise batch extraction method in order to obtain residue samples at a range......Environmental assessment of residue disposal needs to account for long-term changes in leaching conditions. Leaching of heavy metals from incineration residues are highly affected by the leachate pH; the overall environmental consequences of disposing of these residues are therefore greatly...... of pH Values (similar to common pH-dependence tests), and then on these samples to determine leaching of alkalinity as well as remaining solid phase alkalinity. On a range of APC residues covering various pretreatment and disposal options, this procedure was used to determine leachable and residual...

  3. Air pollution control systems in WtE units: An overview

    International Nuclear Information System (INIS)

    Highlights: • The paper describes in brief terms the development of gas cleaning in waste incineration. • The main technologies for pollutant removal are described including their basic mechanisms. • Their respective efficiencies and their application are discussed. • A cautious outlook regarding future developments is made. - Abstract: All WtE (waste-to-energy) plants, based on combustion or other thermal processes, need an efficient gas cleaning for compliance with legislative air emission standards. The development of gas cleaning technologies started along with environment protection regulations in the late 1960s. Modern APC (air pollution control) systems comprise multiple stages for the removal of fly ashes, inorganic and organic gases, heavy metals, and dioxins from the flue gas. The main technologies and devices used for abatement of the various pollutants are described and their basic principles, their peculiarities, and their application are discussed. Few systems for cleaning of synthesis gas from waste gasification plants are included. Examples of APC designs in full scale plants are shown and cautious prospects for the future development of APC systems are made

  4. Air pollution control and decreasing new particle formation lead to strong climate warming

    Directory of Open Access Journals (Sweden)

    R. Makkonen

    2012-02-01

    Full Text Available The number concentration of cloud droplets determines several climatically relevant cloud properties. A major cause for the high uncertainty in the indirect aerosol forcing is the availability of cloud condensation nuclei (CCN, which in turn is highly sensitive to atmospheric new particle formation. Here we present the effect of new particle formation on anthropogenic aerosol forcing in present-day (year 2000 and future (year 2100 conditions. The present-day total aerosol forcing is increased from −1.0 W m−2 to −1.6 W m−2 when nucleation is introduced into the model. Nucleation doubles the change in aerosol forcing between years 2000 and 2100, from +0.6 W m−2 to +1.4 W m−2. Two climate feedbacks are studied, resulting in additional negative forcings of −0.1 W m−2 (+10% DMS emissions in year 2100 and −0.5 W m−2 (+50% BVOC emissions in year 2100. With the total aerosol forcing diminishing in response to air pollution control measures taking effect, warming from increased greenhouse gas concentrations can potentially increase at a very rapid rate.

  5. Replies to Challenges in the Field of Air Pollution Control in Foundry Plants

    Directory of Open Access Journals (Sweden)

    R. Margraf

    2012-09-01

    Full Text Available The solution of applications for air pollution control in foundries for iron and non-ferrous metals may not only be understood as theobservance of requested emission limit values at the stack outlet. An effective environmental protection already starts with the greatest possible capture of pollutants at the source with at the same time minimisation of the volume flow necessary for this. Independent of this, the downstream installed filtration system has to realise a degree of separation of definitely above 99%.Furthermore, when selecting the filter construction, attention has to be paid to a high availability. An even temporarily productionwithout filter will more and more no longer be accepted by residents and authorities. Incidents at the filter lead to a shutdown of the whole production.Additional measures for heat recovery while preparing concepts for filtration plants help to reduce the energy consumption and servefor a sustained conservation of environment.A consequent consideration of the items above is also condition for the fact that environmental protection in foundries remainsaffordable. The lecture deals with the subjects above from the point of view of a plant constructor.

  6. Recent experience with air pollution control on sewage sludge, municipal solid waste and industrial incinerators

    Energy Technology Data Exchange (ETDEWEB)

    Felsvang, K.; Jacobsen, N. [NIRO A/S, Copenhagen (Denmark); Christiansen, O.B. [NIRO Inc., Columbia, MD (United States); Morvan, G. [ABB, Paris (France); Klinke, G. [GEA-Wiegand, Karlsruhe (Germany)

    1996-12-31

    During the last two decades, incineration of sewage sludge, municipal solid waste (MSW) and hazardous waste as a means of volume reduction have grown in importance. Although Europe has been leading the development in the use of incineration, North America today also has a substantial amount of incinerators. As the application of incinerators has increased, concerns have been raised over potential air pollution impacts associated with their use. This has led to the promulgation of emission limits and control requirements for a wide range of pollutants. This paper describes the trends in the emission requirements both in Europe and North America as well as the development of air pollution control technology to cope with the more stringent requirements. The paper describes development of a new process, the High-Performance Spray Dryer Absorber System, which is designed to meet all the new and future emission requirements. Finally the paper deals with mercury removal and results of a 5-year study of mercury revolatilization from dry end product.

  7. Air pollution control systems in WtE units: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Vehlow, J., E-mail: juergen.vehlow@partner.kit.edu

    2015-03-15

    Highlights: • The paper describes in brief terms the development of gas cleaning in waste incineration. • The main technologies for pollutant removal are described including their basic mechanisms. • Their respective efficiencies and their application are discussed. • A cautious outlook regarding future developments is made. - Abstract: All WtE (waste-to-energy) plants, based on combustion or other thermal processes, need an efficient gas cleaning for compliance with legislative air emission standards. The development of gas cleaning technologies started along with environment protection regulations in the late 1960s. Modern APC (air pollution control) systems comprise multiple stages for the removal of fly ashes, inorganic and organic gases, heavy metals, and dioxins from the flue gas. The main technologies and devices used for abatement of the various pollutants are described and their basic principles, their peculiarities, and their application are discussed. Few systems for cleaning of synthesis gas from waste gasification plants are included. Examples of APC designs in full scale plants are shown and cautious prospects for the future development of APC systems are made.

  8. Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators.

    Science.gov (United States)

    Takahashi, Fumitake; Kida, Akiko; Shimaoka, Takayuki

    2010-10-15

    Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories. PMID:20713298

  9. Life-cycle-assessment of the historical development of air pollution control and energy recovery in waste incineration

    DEFF Research Database (Denmark)

    Damgaard, Anders; Riber, C.; Fruergaard, Thilde;

    2010-01-01

    impacts. With regards to the toxic impact categories, emissions from the waste incineration process were always larger than those from the avoided energy production based on natural gas. The results shows that the potential environmental impacts from air emissions have decreased drastically during...... of the waste, but also the energy recovery efficiency has a large importance. The historical development of air pollution control in waste incineration was studied through life-cycle-assessment modelling of eight different air pollution control technologies. The results showed a drastic reduction...... in the release of air emissions and consequently a significant reduction in the potential environmental impacts of waste incineration. Improvements of a factor 0.85–174 were obtained in the different impact potentials as technology developed from no emission control at all, to the best available emission control...

  10. Impact of air pollution control regulations on thermal enhanced oil recovery production in the United States. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Norton, J.F.; Rouge, J.D.; Beekley, P.K.; Husband, S.N.; Arnold, C.W.; Menzies, W.R.; Balentine, H.W.

    1982-03-01

    This study assesses the impact of air pollution control regulations on the costs of present and future thermal enhanced oil recovery (TEOR) production. The conclusions of this study indicate that lengthy permitting processes, limited control sytem availability, and costly control system requirements complicate regulatory compliance and constrain TEOR production expansion. Seven heavy oil production areas with potential for increased TEOR production were selected for detailed analyses. Five of these areas are in California: central Kern County, western Kern County, Coalinga, San Ardo, and Los Angeles Basin. The other two areas are the Slocum field in Texas and the Smackover field in Arkansas. Air pollution control rule and regulation requirements were determined for each production area. State-of-the-art air pollution control technology was assessed and costs were estimated for the control systems needed to comply with previous new source review (NSR) and retrofit rules in each area. For each California production area, the maximum potential increase in TEOR production was estimated, based on available emission offsets. Potential increases in the Texas and Arkansas fields were not projected because production is expected to decrease in these areas. Costs were calculated for the control systems required to allow the maximum increase in TEOR production. An air quality impact analysis was performed for the four largest production areas in California. The results of this analysis allowed estimation of the air quality changes associated with the maximum TEOR production increase and compliance with retrofit and NSR rules.

  11. High-Zinc Recovery from Residues by Sulfate Roasting and Water Leaching

    Science.gov (United States)

    Hu, Ming; Peng, Bing; Chai, Li-yuan; Li, Yan-chun; Peng, Ning; Yuan, Ying-zhen; Chen, Dong

    2015-09-01

    An integrated process for the recovery of zinc that is generated from zinc hydrometallurgy in residues was developed. A mixture of residue and ferric sulfate was first roasted to transform the various forms of zinc in the residue, such as ferrite, oxide, sulfide, and silicate, into zinc sulfate. Next, water leaching was conducted to extract the zinc while the iron remained in the residue as ferric oxide. The effects of the roasting and leaching parameters on zinc recovery were investigated. A maximum zinc recovery rate of 90.9% was achieved for a mixture with a ferric sulfate/residue weight ratio of 0.05 when roasting at 640°C for 30 min before leaching with water at room temperature for 20 min using a liquid/solid ratio of 10. Only 0.13% of the iron was dissolved in the water. Thus, the leaching liquor could be directly returned for zinc smelting.

  12. Kinetics of Pb and Zn leaching from zinc plant residue by sodium hydroxide

    OpenAIRE

    Erdem M.; Yurten M.

    2015-01-01

    In the hydrometallurgical zinc production processes, important amount of hazardous solid extraction residue containing unextractable Zn and Pb is generated. Due to increasing demand of metals and the depletion of high grade natural resources, these types of wastes are gaining great importance in the metallurgical industries. In this study, selective leaching and leaching kinetics of Pb and Zn from zinc extraction residue were investigated. For this purpose;...

  13. Will joint regional air pollution control be more cost-effective? An empirical study of China's Beijing-Tianjin-Hebei region.

    Science.gov (United States)

    Wu, Dan; Xu, Yuan; Zhang, Shiqiu

    2015-02-01

    By following an empirical approach, this study proves that joint regional air pollution control (JRAPC) in the Beijing-Tianjin-Hebei region will save the expense on air pollution control compared with a locally-based pollution control strategy. The evidences below were found. (A) Local pollutant concentration in some of the cities is significantly affected by emissions from their surrounding areas. (B) There is heterogeneity in the marginal pollutant concentration reduction cost among various districts as a result of the cities' varying contribution of unit emission reduction to the pollutant concentration reduction, and their diverse unit cost of emission reduction brought about by their different industry composition. The results imply that the cost-efficiency of air pollution control will be improved in China if the conventional locally based regime of air pollution control can shift to a regionally based one.

  14. Preparation and characterization of inexpensive heterogeneous catalysts for air pollution control. Two case studies

    Energy Technology Data Exchange (ETDEWEB)

    Utsumi, Shigenori; Vallejos-Burgos, Fernando E.; Garcia, Ximena; Gordon, Alfredo L. [Department of Chemical Engineering, University of Concepcion, Concepcion (Chile); Campos, Claudia M.; Pecchi, Gina [Department of Physical Chemistry, University of Concepcion, Concepcion (Chile); Radovic, Ljubisa R. [Department of Chemical Engineering, University of Concepcion, Concepcion (Chile); Department of Energy and Geo-Environmental Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2007-05-30

    Relatively inexpensive heterogeneous catalysts for two reactions of great importance in air pollution control, NO reduction and VOC combustion, were prepared and characterized. Apart from their common practical goal and the frequent need for simultaneous removal of air pollutants, these reactions share a similar redox mechanism, in which the formulation of more effective catalysts requires an enhancement of oxygen transfer. For NO reduction, supported catalysts were prepared by adding a metal (Cu, Co, K) using ion exchange (IE) and incipient wetness impregnation (IWI) to chars obtained from pyrolysis of a subbituminous coal. The effects of pyrolysis temperature, between 550 and 1000 C, on selected catalyst characteristics (e.g., BET surface area, XRD spectrum, support reactivity in O{sub 2}) are reported. For IE catalysts, the surface area increased in the presence of the metals while the opposite occurred for IWI catalysts. For the Co-IE catalysts, the highest surface area was obtained at 700 C. The XRD results showed that, except for Cu (which exhibited sharp Cu{sup 0} peaks), the catalysts may be highly dispersed (or amorphous) on the carbon surface. For the C-O{sub 2} reaction the order of (re)activity was K >> Co > Cu for IE catalysts and K > Cu > Co for IWI catalysts. For NO reduction the orders were K > Co > Cu (IE catalysts) and Cu > Co > K (IWI catalysts). In all cases the catalytic (re)activity for NO reduction was lower than that exhibited for the C-O{sub 2} reaction. The K-IE and Cu-IWI catalysts appeared to be the most promising ones, although further improvements in catalytic activity will be desirable. Some surprising results regarding CO and CO{sub 2} selectivity are also reported, especially for Co catalysts. In VOC combustion, the effect of the nature of ion B (Fe and Ni) on the partial substitution of ion A (Ca for La) in ABO{sub 3} perovskites (e.g., LaFeO{sub 3} and LaNiO{sub 3}) and on their catalytic activity was studied. The perovskite

  15. Process optimization of reaction of acid leaching residue of asbestos tailing and sodium hydroxide aqueous solution

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Silica is the major component of the acid leaching residue of asbestos tailing. The waterglass solution can be prepared by the reaction of the residue with sodium hydroxide aqueous solution. Compared to the high temperature reaction method, this process is environmental friendly and low cost. In this paper, the reaction process of the residue and the sodium hydroxide aqueous solution is optimized. The optimum reaction process parameters are as follows: the usage of sodium hydroxide is 26.4 g/100 g acid leaching residue, the reaction temperature is 90℃, the reaction time is 1 h, and the ratio of the liquid/solid is 2.0. The significance sequence of the process parameters to the alkali leaching reaction effect is the usage of sodium hydroxide > the ratio of the liquid/solid > the reaction time > the reaction temperature. The significance sequence to the leaching ratio of SiO2 is the ratio of the liquid/solid > the usage of sodium hydroxide > the reaction time > the reaction temperature. The significance sequence to the modulus of the sodium silicate is the ratio of the liquid/solid > the usage of sodium hydroxide > the reaction time > the reaction temperature. Under the optimum conditions, the leaching ratio of the SiO2 is 77.5%, and the modulus of the sodium silicate is 3.15. The XRD analysis result indicates that the major components of the alkali leaching residue are serpentine, talc, quartz and some albite.

  16. Major leaching processes of combustion residues - Characterisation, modelling and experimental investigation

    Energy Technology Data Exchange (ETDEWEB)

    Yan Jinying

    1998-12-31

    Characterising leaching behaviour provides ample evidence to identify the major leaching processes of combustion residues. Neutralisation and chemical weathering govern the leaching reactions and control the release of elements from combustion residues, and are thus considered to be the major leaching processes. According to experimental investigations and geochemical simulations, the leaching kinetics of buffering materials are key issues for the understanding of the neutralizing processes. The acid neutralizing capacity at different pH levels depends mainly on the mineralogy of the combustion residues. In combustion residues, the dissolution of glass phases is expected to play an important role in a long-term neutralizing process. The neutralizing process in a flow system is significantly different from that in a batch system. The neutralizing ability of a combustion residue may be strongly affected by solute transport and carbonation reactions in a natural leaching environment. The chemical weathering mainly involves the matrix of combustion residues consisting mostly of glass phases. The dissolution kinetics of waste glass and other possible processes involved in the chemical weathering have been investigated and incorporated into a kinetic reactive transport model. Most important processes in the chemical weathering can be simulated simultaneously using this model. The results show that there is a complicated relationship between the factors controlling the long-term chemical weathering. The environmental impact of the glass dissolution cannot be neglected. Although the glass dissolution provides considerable buffering capacity in long-term weathering, the carbonate is usually a dominant buffering mineral in actual weathering processes. The transformation of carbonate should be considered as an important process in the chemical weathering. The formation of secondary minerals may considerably alter the mineralogy of the waste, and thus change the leaching

  17. Kinetics of Pb and Zn leaching from zinc plant residue by sodium hydroxide

    Directory of Open Access Journals (Sweden)

    Erdem M.

    2015-01-01

    Full Text Available In the hydrometallurgical zinc production processes, important amount of hazardous solid extraction residue containing unextractable Zn and Pb is generated. Due to increasing demand of metals and the depletion of high grade natural resources, these types of wastes are gaining great importance in the metallurgical industries. In this study, selective leaching and leaching kinetics of Pb and Zn from zinc extraction residue were investigated. For this purpose; the effects of NaOH concentration, contact time, stirring speed and temperature on the Pb and Zn recovery from the residue were studied. The shrinking core model was applied to the results of the experiments. Leaching results showed that 85.55% Pb and 21.3 % Zn could be leached under the optimized conditions. The leaching of Pb and Zn were found to fit well to shrinking core model with ash layer diffusion control. Activation energy values for Pb and Zn leaching were calculated to be 13.645 and 22.59 kJ/mol, respectively.

  18. 78 FR 23677 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2013-04-22

    ...) emissions from sources of fugitive dust such as unpaved roads and disturbed soils in open and agricultural... claims that SCAQMD Rule 403, in contrast, controls lots of any size with disturbed surface area and... protective layer of plant residue or other material to a soil surface prior to disturbing the site to...

  19. Process optimization of reaction of acid leaching residue of asbestos tailing and sodium hydroxide aqueous solution

    Institute of Scientific and Technical Information of China (English)

    DU GaoXiang; ZHENG ShuiLin; DING Hao

    2009-01-01

    Silica is the major component of the acid leaching residue of asbestos tailing. The waterglass solution can be prepared by the reaction of the residue with sodium hydroxide aqueous solution. Compared to the high temperature reaction method, this process is environmental friendly and low cost. In this paper, the reaction process of the residue and the sodium hydroxide aqueous solution is optimized. The op-timum reaction process parameters are as follows: the usage of sodium hydroxide is 26.4 g/100 g acid leaching residue, the reaction temperature is 90℃, the reaction time is 1 h, and the ratio of the liq-uid/solid is 2.0. The significance sequence of the process parameters to the alkali leaching reaction effect is the usage of sodium hydroxide > the ratio of the liquid/solid > the reaction time > the reaction temperature. The significance sequence to the leaching ratio of SiO2 is the ratio of the liquid/solid > the usage of sodium hydroxide > the reaction time > the reaction temperature. The significance sequence to the modulus of the sodium silicate is the ratio of the liquid/solid > the usage of sodium hydroxide > the reaction time > the reaction temperature. Under the optimum conditions, the leaching ratio of the SiO2 is 77.5%, and the modulus of the sodium silicate is 3.15. The XRD analysis result indicates that the major components of the alkali leaching residue are serpentine, talc, quartz and some albite.

  20. Chop-leach fuel bundle residues densification by melting

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.G.; Griggs, B.

    1976-11-01

    Two melting processes were investigated for the densification of fuel bundle residues: Industoslag melting and graphite crucible melting. The Industoslag process, with prior decontamination and sorting, can produce ingots of Zircaloy, stainless steel and Inconel of a quality suitable for refabrication and reuse. The process can also melt oxidized mixtures of fuel bundle residues for direct storage. Eutectic mixtures of these materials can be melted in graphite at temperatures of 1300/sup 0/C. Hydrogen absorption experiments with the zirconium-rich alloys show the alloys to be potential tritium reservoirs. 13 figures.

  1. Mercury leaching characteristics of waste treatment residues generated from various sources in Korea.

    Science.gov (United States)

    Cho, Jae Han; Eom, Yujin; Park, Jung-Min; Lee, Sang-Bo; Hong, Ji-Hyung; Lee, Tai Gyu

    2013-07-01

    In this study, mercury (Hg) leaching characteristics of the waste treatment residues (fly ash, bottom ash, sludge, and phosphor powder) generated from various sources (municipal, industrial, medical waste incinerators, sewage sludge incinerator, oil refinery, coal-fired power plant, steel manufacturing plant, fluorescent lamp recycler, and cement kiln) in Korea were investigated. First, both Hg content analysis and toxicity characteristic leaching procedure (TCLP) testing was conducted for 31 collected residue samples. The Hg content analysis showed that fly ash from waste incinerators contained more Hg than the other residue samples. However, the TCLP values of fly ash samples with similar Hg content varied widely based on the residue type. Fly ash samples with low and high Hg leaching ratios (RL) were further analyzed to identify the major factors that influence the Hg leaching potential. Buffering capacity of the low-RL fly ash was higher than that of the high-RL fly ash. The Hg speciation results suggest that the low-RL fly ashes consisted primarily of low-solubility Hg compounds (Hg2Cl2, Hg(0) or HgS), whereas the high-RL fly ashes contain more than 20% high-solubility Hg compounds (HgCl2 or HgSO4). PMID:23680269

  2. Contaminant Leach Testing of Hanford Tank 241-C-104 Residual Waste

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Michelle M.V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buck, Edgar C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-01

    Leach testing of Tank C-104 residual waste was completed using batch and column experiments. Tank C-104 residual waste contains exceptionally high concentrations of uranium (i.e., as high as 115 mg/g or 11.5 wt.%). This study was conducted to provide data to develop contaminant release models for Tank C-104 residual waste and Tank C-104 residual waste that has been treated with lime to transform uranium in the waste to a highly insoluble calcium uranate (CaUO4) or similar phase. Three column leaching cases were investigated. In the first case, C-104 residual waste was leached with deionized water. In the second case, crushed grout was added to the column so that deionized water contacted the grout prior to contacting the waste. In the third case, lime was mixed in with the grout. Results of the column experiments demonstrate that addition of lime dramatically reduces the leachability of uranium from Tank C-104 residual waste. Initial indications suggest that CaUO4 or a similar highly insoluble calcium rich uranium phase forms as a result of the lime addition. Additional work is needed to definitively identify the uranium phases that occur in the as received waste and the waste after the lime treatment.

  3. Influence of ageing of residues on the availability of herbicides for leaching

    International Nuclear Information System (INIS)

    Losses by leaching of chlorotoluron, isoproturon and triasulfuron from small intact columns of a structured clay loam and an unstructured sandy loam soil were measured in five separate field experiments. In general, losses of all three herbicides were greater from the clay loam than from the sandy loam soil and the order between herbicides was always triasulfuron>>isoproturon>chlorotoluron. Differences between experiments were also consistent for every soil/herbicide combination. There was no relationship between total loss and either total rainfall or cumulative leachate volume. When weighting factors were applied to the rainfall data to make early rainfall more important than later rainfall, there were significant positive relationships between cumulative weighted rainfall and total losses. Also, there were significant negative correlations between total losses and the delay to accumulation of 25 mm rainfall (equivalent to one pore volume of available water) in the different experiments. In laboratory incubations, there was a more rapid decline in aqueous (0.01 M calcium chloride) extractable residues than in total solvent extractable residues indicating increasing sorption with residence time. However, the rate of change in water extractable residues could not completely explain the decrease in leachability with ageing of residues in the field. Short-term sorption studies with aggregates of the two soils indicated slower sorption by those of the clay loam than by those of the sandy loam suggesting that diffusion into and out of aggregates may affect availability for leaching in the more structured soil. Small scale leaching studies with aggregates of the soils also demonstrated reductions in availability for leaching as residence time in soil was increased, which could not be explained by degradation. These results therefore indicate that time-dependent sorption processes are important in controlling pesticide movement in soils, although the data do not give a

  4. Automobile air pollution: control equipment. Volume 1. 1964-1978 (citations from the NTIS data base). Report for 1964-78

    Energy Technology Data Exchange (ETDEWEB)

    Cavagnaro, D.M.

    1980-02-01

    Research reports on air pollution control equipment used in automobiles are cited. Topics include the design and performance of catalytic and thermal reactors, retrofit devices, carburetors, and ignition timing systems. Also covered are studies of the catalysts as well as the equipment regulations that the industry must follow. (This updated bibliography contains 259 abstracts, none of which are new entries to the previous edition.)

  5. Leaching behavior of several zinc rich residues in a hydrometallurgical recycling process

    OpenAIRE

    Pedrosa, Fátima; Cabral, Marta; Nogueira, C. A.; Margarido, F.

    2009-01-01

    The leaching of metals contained in spent Zn-MnO2 batteries and electric arc furnace (EAF) dusts using sulfuric acid solutions was studied, in order to evaluate the feasibility of simultaneous treatment of both wastes by a hydrometallurgical process. In both residues, a substantial quantity of zinc was solubilized (about 100% in batteries and 70-80% in EAF dusts) in diluted acid solutions and room temperature, corresponding to the reaction of zinc oxide species. Other species were more refrac...

  6. Extraction of Zinc from Electric Arc Furnace Dust by Alkaline Leaching Followed by Fusion of the Leaching Residue with Caustic Soda

    Institute of Scientific and Technical Information of China (English)

    赵由才; R.Stanforth

    2004-01-01

    Extractability of zinc from two types of electric arc furnace (EAF) dusts containing 24.8% and 16.8% of zinc respectively (denoted as Sample A and Sample B) were tested using direct alkaline leaching followed by fusion of the resulting leaching residues with caustic soda. The experimental results show that the extraction of zinc is heavily dependent on the contents of iron in the dusts. The higher iron content, the lower extraction of zinc is obtained. 53% and 38% of zinc can be extracted when both dusts were directly contacted with 5mol·L-1 NaOH solution for 42h. The remaining zinc left in the leaching residues, which supposed to be present as zinc ferrites, can be further leached when the residues were fused with caustic soda. Quantitative extraction of zinc can be obtained from the leaching residue of Sample A while only 85% from Sample B. The extractability of zinc from dusts wit hvarious contents of iron is compared. The production flowsheet for zinc from the dusts using the process proposed is discussed.

  7. Win-Win strategies to promote air pollutant control policies and non-fossil energy target regulation in China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lining; Patel, Pralit L.; Yu, Sha; Liu, Bo; Mcleod, Jeffrey D.; Clarke, Leon E.; Chen, Wenying

    2016-02-01

    The rapid growth of energy consumption in China has led to increased emissions of air pollutants. As a response, in its 12th Five Year Plan the Chinese government proposed mitigation targets for SO2 and NOx emissions. Herein we have investigated mitigation measures taken in different sectors and their corresponding impacts on the energy system. Additionally, as non-fossil energy development has gained traction in addressing energy and environmental challenges in China, we further investigated the impact of non-fossil energy development on air pollutant emissions, and then explored interactions and co-benefits between these two types of policies. An extended Global Change Assessment Model (GCAM) was used in this study, which includes an additional air pollutant emissions control module coupling multiple end-of-pipe (EOP) control technologies with energy technologies, as well as more detailed end-use sectors in China. We find that implementing EOP control technologies would reduce air pollution in the near future, but with little room left to implement these EOP technologies, other cleaner and more efficient technologies are also effective. These technologies would reduce final energy consumption, increase electricity’s share in final energy, and increase the share of non-fossil fuels in primary energy and electricity consumption. Increasing non-fossil energy usage at China’s proposed adoption rate would in turn also reduce SO2 and NOx emissions, however, the reductions from this policy alone still lag behind the targeted requirements of air pollutant reduction. Fortunately, a combination of air pollutant controls and non-fossil energy development could synergistically help realize the respective individual targets, and would result in lower costs than would addressing these issues separately.

  8. Hanford Tank 241-S-112 Residual Waste Composition and Leach Test Data

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J.; Krupka, Kenneth M.; Geiszler, Keith N.; Lindberg, Michael J.; Arey, Bruce W.; Schaef, Herbert T.

    2008-08-29

    This report presents the results of laboratory characterization and testing of two samples (designated 20406 and 20407) of residual waste collected from tank S-112 after final waste retrieval. These studies were completed to characterize the residual waste and assess the leachability of contami¬nants from the solids. This is the first report from this PNNL project to describe the composition and leach test data for residual waste from a salt cake tank. All previous PNNL reports (Cantrell et al. 2008; Deutsch et al. 2006, 2007a, 2007b, 2007c) describing contaminant release models, and characterization and testing results for residual waste in single-shell tanks were based on samples from sludge tanks.

  9. 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)

  10. Zinc Extraction from Zinc Plants Residue Using Selective Alkaline Leaching and Electrowinning

    Science.gov (United States)

    Ashtari, Pedram; Pourghahramani, Parviz

    2015-10-01

    Annually, a great amount of zinc plants residue is produced in Iran. One of them is hot filter cake (known as HFC) which can be used as a secondary resource of zinc, cobalt and manganese. Unfortunately, despite its heavy metal content, the HFC is not treated. For the first time, zinc was selectively leached from HFC employing alkaline leaching. Secondly, leaching was optimized to achieve maximum recovery using this method. Effects of factors like NaOH concentration (C = 3, 5, 7 and 9 M), temperature (T = 50, 70, 90 and 105 °C), solid/liquid ratio (weight/volume, S/L = 1/10 and 1/5 W/V) and stirring speed (R = 500 and 800 rpm) were studied on HFC leaching. L16 orthogonal array (OA, two factors in four levels and two factors in two levels) was applied to determine the optimum condition and the most significant factor affecting the overall zinc extraction. As a result, maximum zinc extraction was 83.4 %. Afterwards, a rough test was conducted for zinc electrowinning from alkaline solution according to the common condition available in literature by which pure zinc powder (99.96 %) was successfully obtained.

  11. The Experience of Japanese Air Pollution Control Is Worth Learning%日本对大气污染控制的经验值得借鉴

    Institute of Scientific and Technical Information of China (English)

    陈韶秀

    2005-01-01

    This article explains the concept of Social Environmental Management Capacity Building and its meaning on sustainable development, In addition, it also describes the evolvement of the Social Environmental Management System, Through a case study on good practice of air pollution control in Japan and its implication to China, the article gives advice that it should be necessary to establish a thorough Social Environmental Management System and to design relative indexes to evaluate the Social Environmental Management Capacity in China, which may contributes to the development of the system to the level of self-management and which might boost the overall welfare of human beings. In the end, based on Social Environmental Management System, this article gives concrete advice on air pollution control and Environmental Management Capacity Building in China。

  12. Simultaneous Pressure Oxidation Leaching of Zinc Sulfide Concentrate and Neutral Leaching Residue%闪锌矿与中性浸出渣合并氧压酸浸

    Institute of Scientific and Technical Information of China (English)

    梁铎强; 王吉坤; 周廷熙; 张怀伟

    2009-01-01

    硫化锌精矿和由传统流程得到的中浸渣混在一块,对其进行了浸出的小型试验.试验在不同的条件下进行,以考察影响浸出的各种因素,包括浸出温度、浸出时间、氧分压和搅拌速度.试验在一个两升的高压釜内进行.试验结果表明了硫化锌精矿和中浸渣能相到促进浸出,但只有在一定的浸出条件下这种耦合作用才表现得比较明显.研究过程中一些机理也得到了证实.最后为了后面的扩大试验提供了关键的浸出条件:浸出温度135℃;浸出时间2h;氧分压0.8MPa;初始酸度120g/L.%Lab-scale simultaneous leaching of zinc sulfide concentrate and neutral leaching residue obtained by traditional roast-leachelectrowin (RLE) were performed in various conditions to investigate leaching variables such as leaching temperature, leaching duration, oxygen partial pressure and stirring rate. Experiments were carried out in a 2-liter autoclave. Experimental results show that zinc sulfide concentrate and the neutral leaching residue help each other to leach in such simultaneous leaching experiments, but the coupling effect occurs obviously only in a given leaching conditions. In this work some mechanisms are proved in the experiments. For the sake of subsequent scaleup experiment,the reasonable condition of simultaneous leaching is given as follows,leaching temperature,135%;leaching duration,2hr;oxygen partial pressure,0.8MPa; initial acidity,120g/l.

  13. Leaching and soil/groundwater transport of contaminants from coal combustion residues

    International Nuclear Information System (INIS)

    In this project the results of accelerated laboratory leaching tests on coal fly ash and flue gas desulfurization (FGD) products from the spray dryer absorption process (SDA) were evaluated by comparison to the results of large scale lysimeter leaching tests on the same residues. The mobility of chromium and molybdenum - two of the kev contaminants of coal combustion residue leachates - in various typical soil types was investigated by batch and column methods in the laboratory. Some of the results were confirmed by field observations at an old coal fly ash disposal site and by a lysimeter attenuation test with coal fly ash leachate on a clayed till. A large number of groundwater transport models and geochemical models were reviewed, and two of the models (Gove-Stollenwerk and CHMTRNS) were modified and adjusted and used to simulate column attenuation tests performed in the laboratory. One of the models (Grove-Stollenwerk) was used to illustrate a recommended method of environmental impact assessment, using lysimeter leaching data and laboratory column attenuation data to describe the emission and migration of Mo from a coal fly ash disposal site

  14. Two-stage fungal leaching of vanadium from uranium ore residue of the leaching stage using statistical experimental design

    International Nuclear Information System (INIS)

    Highlights: ► In this work, the percent of vanadium recovery from uranium mine waste was 44.8. ► Unlike autotrophs, Aspergillus niger is a suitable microorganism to deal with such a resource. ► In the first step of the present work, citric acid was produced more than the other acids. ► When sterilization of uranium ore waste is not economic, two-step bioleaching is an appropriate method. - Abstract: In this investigation, bioleaching of vanadium from uranium ore residue of the leaching stage was studied by Aspergillus niger in a two-step process at 30 °C and 150 rpm. The first step was initiated by growth of fungi in the absence of mine waste. Using response surface methodology, three factors were surveyed for fungal growth: initial pH, sucrose concentration and spore population. Also concentrations of oxalic, citric, and gluconic acids were measured as response in this step. During 30 days, maximum productions of these acids were 3265, 11578, and 7988 mg/l, respectively. Initial pH and sucrose concentration were significant factors for oxalic and citric acid production; however, for gluconic acid production sucrose concentration and spore population were significant. Then, the content of each flask was filtered and mine waste was added to liquor with pulp density of 3%. During 3 days, in the second step, vanadium recovered about 44.8% in the liquor

  15. Part 1: Logging residues in piles - Needle loss and fuel quality. Part 2: Nitrogen leaching under piles of logging residues

    International Nuclear Information System (INIS)

    Part 1: Experimental piles were built in three geographical locations during May-Sept. 1989. Logging residues consisted of 95% spruce and 5% pine. Height of the piles varied between 80 and 230 cm. Needles were collected by placing drawers under 40 randomely chosen piles. The drawers were emptied every two weeks during the storage period. Natural needle loss was between 18 and 32% of the total amount of needles after the first two months of storage. At the end of the storage period, 24-42% of the needles had fallen down to the drawers. At the end of the experiment the total needle fall was 95-100% in the shaken piles. According to the results of this study piles smaller than 150 cm had the most effective needle fall. Piles should be placed on open places where the air and sun heat penetrate and dry them. Needles were the most sensitive fraction to variations in precipitation compared to the other components, such as branches. Piles usually dried quickly, but they also rewet easily. This was especially true in the smaller piles. The lowest moisture content was measured at the end of June. The ash content in needles varied between 4 and 8%. 16 refs., 15 figs. Part 2: Three field experiments were equipped with no-tension humus lysimeters. Pairs of lysimeters with the same humus/field layer vegetation material were placed in pairs, one under a pile of felling residues and another in the open clear felling. Leaching of nitrogen as well as pH and electric conductivity in the leachate was followed through sampling of the leachate at regular intervals. The results from the investigation show that: * the amount of leachate was higher in lysimeters in the open clear felling, * pH in the leachate was initially lower under piles of felling residues, * the amount of nitrogen leached was higher in the open clear felling. Thus, storing of felling residues in piles during the summer season did not cause any increase in nitrogen leaching, which had been considered to be a risk

  16. Extraction of metals from automotive shredder residue:Preliminary results of different leaching systems

    Institute of Scientific and Technical Information of China (English)

    Francesco Ferella; Ida De Michelis; Agostino Scocchera; Mario Pelino; Francesco Vegliò

    2015-01-01

    The study is focused on the extraction of valuable metals from automotive shredder residue (ASR) by different leaching solutions. First, ASR samples were roasted at 600 °C to simulate a thermal treatment processing. Distil ed water, citric and sulphuric acid were preliminarily investigated, thus two further full factorial systems entailing H2SO4–H2O2 and H2SO4–H2O2–Fe3+ were tested. The preliminary experimental results showed that 0.1 mol·L−1 H2SO4 solution extracted 100%of Cu, Fe and Zn, whereas citric acid leached 100%of Zn and Pb, 59%of Fe and 62%of Cu;whereas, H2SO4–H2O2 and H2SO4–H2O2–Fe3+(Fenton's) leaching media showed that Cu, Fe and Zn can be extracted simultaneously and completely from the ASR ashes before final disposal.

  17. Reductive leaching behavior of zinc from neutral leaching residue in zinc smelting%锌冶炼中浸渣锌还原浸出行为研究

    Institute of Scientific and Technical Information of China (English)

    闵小波; 张建强; 张纯; 王密; 周波生; 沈忱

    2015-01-01

    以湿法炼锌中浸渣为研究对象,通过对比几种不同类型还原剂对中浸渣中铁酸锌浸出效果,筛选铁酸锌高效还原浸出药剂-硫酸肼,并考察硫酸肼浓度、时间、初始酸度、温度及液固比对锌浸出效果的影响.探讨浸出过程中锌物相转变机制.在浸出初始阶段主要是锌的硫酸盐、氧化物、硅酸盐及硫化物等易溶态溶出,而铁酸锌在浸出120 min后大部分溶出.在优化条件下Zn和Fe的浸出率分别达到了95.83%和94.19%.%This paper describes the behavior of reductive leaching of zinc from neutral leaching residue in zinc smelting. The effective reductant of hydrazine sulfate was selected by investigating the extraction efficiency of zinc from neutral leaching residue in zinc hydrometallurgical process among various types of reductant. The effects of initial concentration of hydrazine sulfate and sulfuric acid, retention, temperature and liquid-solid ratio on extraction were studied. Furthermore the transformation of zinc phases during the leaching was illustrated. The sulfate, oxide, silicate and sulfide of zinc were extracted fast at first and zinc ferrite was mostly leached out after reaction for 120 min. The leaching efficiencies of Zn and Fe were 95.83 % and 94.19 %respectively in optimum conditions.

  18. The determination, by x-ray-fluorescence spectrometry, of noble and base metals in matte-leach residues

    International Nuclear Information System (INIS)

    An accurate and precise method is described for the determination of noble and base metals in matte-leach residues. Preparation of the samples essentially involves fusion with sodium peroxide in a zirconium crucible and leaching with hydrochloric and nitric acids. Matrix correction and calibration are achieved by use of the single-standard calibration method with reference solutions prepared from pure metals or from compounds of the element to be determined

  19. 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. PMID:26421313

  20. 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.

  1. Test of electrodialytic upgrading of MSWI APC residue in pilot scale: focus on reduced metal and salt leaching

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Jensen, Pernille Erland; Villumsen, Arne;

    2010-01-01

    that is adapted from conventional electrodialysis, e.g. used in desalination of solutions. The APC residue was treated in a suspension (8 kg APC residue and 80 L tap water) and circulated through an electrodialytic (ED) stack consisting of 50 cell pairs separated by ion exchange membranes. A direct current...... was applied to the ED stack for removal of heavy metals (As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Zn) and salts (Cl, Na, SO4) from the APC residue suspension. Different tank designs for mixing the APC residue suspension were tested as well as changing experimental conditions. A part of the raw experimental APC residue...... was carbonated by reaction with CO2 under moist conditions prior to electrodialytic treatment. The carbonation alone reduced the leaching of some heavy metals. However, it was not sufficient to reduce the heavy metal or salt leaching to meet the Danish Category 3 guideline levels for waste material reuse...

  2. 新型硫化物助剂强化浸出酸浸渣中铁的研究%Study on Intensified Leaching of Ferric Iron from Acid-leach Residues Using Sulfide as a Novel Leaching Agent

    Institute of Scientific and Technical Information of China (English)

    金程; 赵颖华; 李登新

    2011-01-01

    采用硫化物作助剂强化溶浸酸浸渣中的氧化铁.分别进行了助浸剂用量、硫酸用量、时间、温度、液固比等条件试验,考察其对酸溶效果的影响,结果表明:当助剂与渣质量比为0.69:1,硫酸过剩系数为1.4,起始液固比为2:1,搅拌速度为1 300 r/min时,在95℃下反应2h,铁的浸取率可以达到89.2%,助剂中锌的浸出率为90.2%,尾渣易于进一步提金.与现行技术条件相比,硫酸用量大大减少,工艺简单,能耗低.%Taking sulfide as a leaching agent, tests were conducted on the intensified-leaching of iron oxide from acid-leach residue. Influence of different factors, such as consumption of leaching agent, dosage of sulfuric acid, leaching time and temperature, as well as liquid-solid ratio, on the leaching effect was investigated. Results show that iron leaching rate reaches 89.2% and the leach rate of zinc from leaching agent is 90.2% under the following conditions of the initial liquid/solid ratio being 1'-1, the mass ratio of leaching agent to residue being 0. 69: 1, excess coefficient of sulfuric acid being 1.4, with a stirring rate at 1 300 r/min and reaction at the temperature of 95 X. For 2 h. The tailings obtained can also be used for further gold-extraction. This process is simple with low energy consumption compared with the existing technology, and sulfuric acid consumption is greatly reduced.

  3. 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)

  4. Chapter 4. Uranium extraction technology from wastes of uranium industry. 4.1. Sulfuric acid leaching kinetics of residues from anthropogenic deposit Map 1-9

    International Nuclear Information System (INIS)

    Present article is devoted to sulfuric acid leaching kinetics of residues from anthropogenic deposit Map 1-9. Since residues from anthropogenic deposit Map 1-9 basically contain quartz (69%), it went through acid leaching. Results of laboratory investigations on the opening degree and uranium conversion to solution were summarized. The influence of sulfuric acid consumption on uranium extraction during leaching (U = 0,018%, t =20 deg C, t = 10 hours) was considered. The kinetic and energetic parameters of residues leaching of anthropogenic deposit Map 1-9 was discussed. The basic process flow diagram of uranium industry wastes reprocessing was proposed.

  5. Residual organic matter and microbial respiration in bottom ash: Effects on metal leaching and eco-toxicity.

    Science.gov (United States)

    Ilyas, A; Persson, K M; Persson, M

    2015-09-01

    A common assumption regarding the residual organic matter, in bottom ash, is that it does not represent a significant pool of organic carbon and, beyond metal-ion complexation process, it is of little consequence to evolution of ash/leachate chemistry. This article evaluates the effect of residual organic matter and associated microbial respiratory processes on leaching of toxic metals (i.e. arsenic, copper, chromium, molybdenum, nickel, lead, antimony and zinc), eco-toxicity of ash leachates. Microbial respiration was quantified with help of a respirometric test equipment OXITOP control system. The effect of microbial respiration on metal/residual organic matter leaching and eco-toxicity was quantified with the help of batch leaching tests and an eco-toxicity assay - Daphnia magna. In general, the microbial respiration process decreased the leachate pH and eco-toxicity, indicating modification of bioavailability of metal species. Furthermore, the leaching of critical metals, such as copper and chromium, decreased after the respiration in both ash types (fresh and weathered). It was concluded that microbial respiration, if harnessed properly, could enhance the stability of fresh bottom ash and may promote its reuse. PMID:25999368

  6. Leaching of Antimony (Sb)from Municipal Solid Waste Incineration (MSWI) Residues

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Inga

    2004-07-01

    The mobility of antimony (Sb) in municipal solid waste incineration (MSWI) residues often exceeds the limit values stipulated by the European Union. As an ash treatment by washing is conceivable, this work investigated the Sb release from Swedish bottom ash and fly ash when mixed with water. The leaching experiments revealed the factors significantly (a = 0.05) affecting Sb release from the ashes. The following factors were investigated: Liquid to solid ratio (L/S), time, pH, carbonation (treatment with CO{sub 2}), ultrasonics and temperature. The data were evaluated using multiple linear regression (MLR). The impact of the factors could be quantified. The maximum Sb release calculated was 13 mg/kg DM for bottom ash and 51 mg/kg DM for fly ash. The derived models explained the observed data well. Nevertheless, the calculated values were subject to a high uncertainty. For bottom ash, a lowering of the Sb total content of approximately 22% could be achieved. If this also involves a sufficient lowering of the Sb mobility to meet EU limit values could not yet be assessed. Chemical equilibrium calculations were performed to explain the empirical results. However, no solid phases controlling Sb release from the ashes could be identified.

  7. Digestion Study of Water Leach Purification (WLP) Residue for Possibility of Thorium Extraction

    International Nuclear Information System (INIS)

    Water leach purification (WLP) is the main residue being produced by Lynas Advanced Materials Plant (LAMP). During rare earths elements extraction process, thorium is removed completely to WLP. The objective of this study was to extract thorium from WLP in order to reduce the level of radioactivity and to store Th for future nuclear fuel. Alkali and concentrated acids process was used to recover the Th from WLP. The concentration of Th and U in WLP was determined by Instrumental Neutron Activation Analysis (INAA) and found to be 1952.9 ± 17.6 mg/ kg and 17.2 ± 2.4 mg/ kg respectively. Digestion process of WLP via sodium hydroxide, concentrated nitric and sulphuric acids using different time and temperature has been tested. The Th concentrations in liquid phrase were determined by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). In both processes less than 5 % recovery of Th has been achieved. This study showed that very low Th recovery was achieved due to thorium was probably converted into refractory and insoluble form through the calcination stage of LAMP processing. Therefore different techniques should be used to recover the thorium. (author)

  8. 碱性加压浸出三次氨浸渣中钼的实验研究%Experimental Study on Alkaline Pressure Leaching of Molybdenum from Ammonia Leach Residues

    Institute of Scientific and Technical Information of China (English)

    沈裕军; 杨文魁; 公彦兵; 丁喻

    2011-01-01

    采用加压碱浸的方法浸出钼焙砂三次氨浸渣中的钼,研究了浸出剂、温度、时间、催化剂等对钼浸出率的影响,得出钼浸出最优条件为:Na2CO3加入量为30%,液固比为3,催化剂A加入量为6%,温度为180℃,浸出时间为1h,此条件下钼浸出率可达98%;进行了4次连续循环浸出试验,钼浸出率均在98%以上.%Pressure alkaline leaching was introduced to extract molybdenum from ammonia leaching residues after molybdenum was treated by ammonia leaching process for three times. The effects of leaching agent, temperature, time and catalyst on the leaching rate of molybdenum were investigated. The best leaching conditions of molybdenum were as follows; the addition amount of Na2CO, was 30% , liquid-solid ratio was 3, the addition amount of catalyst A was 6% , the temperature was 180 ℃ and leaching time was 1 h. Under these conditions the leaching rate of molybdenum reached 98% , and the leaching rate of molybdenum from four cycling leaching experiments were all above 98%.

  9. Copper Leaching from Copper Residue with Oxygen in Sulfuric Acid/Chloride Solution DENG Tong 1,%在硫酸/氯化物深液中用氧气浸出铜渣中的铜

    Institute of Scientific and Technical Information of China (English)

    邓彤; 文震

    2000-01-01

    Leaching of a copper residue, produced by selected oxidation leaching of a nickel matte, in oxygenated sulfuric acid solution with the participation of chloride was investigated. The effects of quantity of chloride, flowrate of oxygen, concentration of sulfuric acid and temperature were discussed as leaching variables. Addition of chloride in small amount into the leach slurry was justified in enhancing copper leaching from the residue.

  10. Evaluation of resource recovery from waste incineration residues--the case of zinc.

    Science.gov (United States)

    Fellner, J; Lederer, J; Purgar, A; Winterstetter, A; Rechberger, H; Winter, F; Laner, D

    2015-03-01

    Solid residues generated at European Waste to Energy plants contain altogether about 69,000 t/a of Zn, of which more than 50% accumulates in air pollution control residues, mainly boiler and filter ashes. Intensive research activities aiming at Zn recovery from such residues recently resulted in a technical scale Zn recovery plant at a Swiss waste incinerator. By acidic leaching and subsequent electrolysis this technology (FLUREC) allows generating metallic Zn of purity>99.9%. In the present paper the economic viability of the FLUREC technology with respect to Zn recovery from different solid residues of waste incineration has been investigated and subsequently been categorised according to the mineral resource classification scheme of McKelvey. The results of the analysis demonstrate that recovery costs for Zn are highly dependent on the costs for current fly ash disposal (e.g. cost for subsurface landfilling). Assuming current disposal practice costs of 220€/ton fly ash, resulting recovery costs for Zn are generally higher than its current market price of 1.6€/kg Zn. With respect to the resource classification this outcome indicates that none of the identified Zn resources present in incineration residues can be economically extracted and thus cannot be classified as a reserve. Only for about 4800 t/a of Zn an extraction would be marginally economic, meaning that recovery costs are only slightly (less than 20%) higher than the current market price for Zn. For the remaining Zn resources production costs are between 1.5 and 4 times (7900 t/a Zn) and 10-80 times (55,300 t/a Zn) higher than the current market value. The economic potential for Zn recovery from waste incineration residues is highest for filter ashes generated at grate incinerators equipped with wet air pollution control. PMID:25458759

  11. Evaluation of resource recovery from waste incineration residues--the case of zinc.

    Science.gov (United States)

    Fellner, J; Lederer, J; Purgar, A; Winterstetter, A; Rechberger, H; Winter, F; Laner, D

    2015-03-01

    Solid residues generated at European Waste to Energy plants contain altogether about 69,000 t/a of Zn, of which more than 50% accumulates in air pollution control residues, mainly boiler and filter ashes. Intensive research activities aiming at Zn recovery from such residues recently resulted in a technical scale Zn recovery plant at a Swiss waste incinerator. By acidic leaching and subsequent electrolysis this technology (FLUREC) allows generating metallic Zn of purity>99.9%. In the present paper the economic viability of the FLUREC technology with respect to Zn recovery from different solid residues of waste incineration has been investigated and subsequently been categorised according to the mineral resource classification scheme of McKelvey. The results of the analysis demonstrate that recovery costs for Zn are highly dependent on the costs for current fly ash disposal (e.g. cost for subsurface landfilling). Assuming current disposal practice costs of 220€/ton fly ash, resulting recovery costs for Zn are generally higher than its current market price of 1.6€/kg Zn. With respect to the resource classification this outcome indicates that none of the identified Zn resources present in incineration residues can be economically extracted and thus cannot be classified as a reserve. Only for about 4800 t/a of Zn an extraction would be marginally economic, meaning that recovery costs are only slightly (less than 20%) higher than the current market price for Zn. For the remaining Zn resources production costs are between 1.5 and 4 times (7900 t/a Zn) and 10-80 times (55,300 t/a Zn) higher than the current market value. The economic potential for Zn recovery from waste incineration residues is highest for filter ashes generated at grate incinerators equipped with wet air pollution control.

  12. RESEARCH ON REDUCTION OF MOLYBDENUM CONTENT IN AMMONIA LEACHING RESIDUES%降低氨浸渣中钼含量的研究

    Institute of Scientific and Technical Information of China (English)

    冯宝奇; 郭金亮; 马高峰; 白宏斌; 王伟; 田莎莎; 谢亚宁; 王子川

    2013-01-01

    对传统工艺制备钼酸铵的酸洗、氨浸工艺进行研究,确定氨浸渣中钼含量高低的主要影响因素.通过试验研究,降低氨浸渣中钼含量.%By studying pickling and ammonia leaching progress in the traditional preparation of ammonium molybdate,the main factor influencing the content of molybdenum in ammonia leaching residues was determined.Thus,experiments for reducing the content of molybdenum in ammonia leaching residues were conducted.

  13. Leaching mechanism of zinc powder replacement residue containing gallium and germanium by high pressure acid leaching%锌粉置换镓锗渣高压酸浸的浸出机理

    Institute of Scientific and Technical Information of China (English)

    刘付朋; 刘志宏; 李玉虎; 刘智勇; 李启厚

    2014-01-01

    The high pressure acid leaching of zinc powder replacement residue containing gallium and germanium was carried out. The effects of sulfuric acid concentration, liquid to solid ratio, time, temperature, as well as the kind and concentration of leaching assistant agents on the leaching rates of gallium and germanium were studied, the filterabilities of the leaching residues were also investigated. The results show that increasing sulfuric acid concentration till 156 g/L benefits the leaching of gallium and germanium. Above this point, the leaching rate of germanium will decrease. The increase of leaching time or temperature has little influence on the leaching rates of gallium and germanium, but the filterabilities of leaching residues are improved obviously. Adding cadmium nitrate or sodium nitrate can improve the leaching of gallium and germanium, moreover, adding cadmium nitrate can also improves the filterability of the leaching residue sharply. The sample of zinc powder replacement residues is leached for 3 h under the conditions of sulfuric acid concentration of 156 g/L, cadmium nitrate concentration of 60 g/L as leaching assistant agent, liquid to solid ratio of 8, temperature of 150℃, the leaching rates obtained are over 98% for gallium and over 94% for germanium, respectively. Moreover, the filterability of the leaching residue is 20 times more than that of the residue obtained under normal pressure acid leaching condition.%研究锌粉置换镓锗渣的高压酸浸过程,考察硫酸浓度、液固比、浸出时间、浸出温度、助浸剂种类和添加量对Ga、Ge浸出率以及浸出渣过滤性能的影响。结果表明:增加硫酸浓度有利于Ga、Ge的浸出,但硫酸浓度超过156 g/L后,反而不利于Ge的浸出。浸出时间和温度对Ga、Ge浸出率影响较小,但增加浸出时间或提高反应温度均有利于改善浸出渣的过滤性能。添加硝酸钠或硝酸钙均可促进Ga、Ge

  14. Leaching and selective copper recovery from acidic leachates of Três Marias zinc plant (MG, Brazil) metallurgical purification residues.

    Science.gov (United States)

    Sethurajan, Manivannan; Huguenot, David; Lens, Piet N L; Horn, Heinrich A; Figueiredo, Luiz H A; van Hullebusch, Eric D

    2016-07-15

    Zinc plant purification residue (ZPR), a typical Zn-hydrometallurgical waste, was collected from the Três Marias Zn plant (MG, Brazil). ZPR was characterized for its metal content and fractionation, mineralogy, toxicity and leachability. Toxicity characteristics leaching procedure (TCLP) and European Community Bureau of Reference (BCR) sequential extraction results revealed that this ZPR displays high percentages of metals (Cd, Cu, Zn and Pb) in the highly mobilizable fractions, increasing its hazardous potential. Bulk chemical analysis, pH dependent leaching and acid (H2SO4) leaching studies confirm that the ZPR is polymetallic, rich in Cd, Cu and Zn. The sulfuric acid concentration (1 M), agitation speed (450 rpm), temperature (40 °C) and pulp density (20 g L(-1)) were optimized to leach the maximum amount of heavy metals (Cd, Cu and Zn). Under optimum conditions, more than 50%, 70% and 60% of the total Cd, Cu and Zn present in the ZPR can be leached, respectively. The metals in the acid leachates were investigated for metal sulfide precipitation with an emphasis on selective Cu recovery. Metal sulfide precipitation process parameters such as initial pH and Cu to sulfide ratio were optimized as pH 1.5 and 1:0.5 (Cu:sulfide) mass ratio, respectively. Under optimum conditions, more than 95% of Cu can be selectively recovered from the polymetallic ZPR leachates. The Cu precipitates characterization studies reveal that they are approximately 0.1 μm in diameter and mainly consist of Cu and S. XRD analysis showed covellite (CuS), chalcanthite (CuSO4·5H2O) and natrochalcite (NaCu2(SO4)2(OH)·H2O) as the mineral phases. ZPRs can thus be considered as an alternative resource for copper production. PMID:27074201

  15. 热酸浸出锌浸渣中镓锗的研究%Extracting Gallium and Germanium from Zinc-leaching Residues by Hot-acid Leaching Process

    Institute of Scientific and Technical Information of China (English)

    马喜红; 覃文庆; 吴雪兰; 任浏祎

    2012-01-01

    研究了锌浸渣热酸浸出过程的工艺条件,分析了浸出热力学和动力学机理,并用于指导回收稀有金属镓和锗.实验结果表明,锌浸渣中镓和锗浸出的最佳工艺条件为:硫酸初始质量浓度为188 g/L,反应温度为95℃,反应时间为3h,液固比为5∶1,搅拌速度为300 r/min,该条件下多组综合实验的酸浸出液中Ga和Ge的浸出率均高于86%和62%.锌浸渣中金属镓锗的浸出过程在动力学上属于“未反应核减缩”模型,浸出过程主要受反应温度、始酸浓度、反应时间的影响,反应由界面化学反应控制.%Extraction of gallium and germanium from zinc leaching residue was carried out by hot-acid leaching. The effects of leaching agent ( sulfuric acid) , leaching temperature, leaching time, L/S ratio and agitation speed on the leaching rate of Ga and Ge were examined, while the thermodynamics and dynamic mechanism for the leaching were, also analyzed. Results showed that the optimal leaching conditions were as follows: the initial mass concentration of sulfuric acid was 188 g/L, leaching temperature was 95 ℃ , leaching time was 3 h, L/S ratio was 5:1, and agitation speed was 300 r/min. Under these conditions, the leaching rates of Ga and Ge in acid leaching solution from multi-group comprehensive tests were averagely above 86% and 62% , respectively. Furthermore, the leaching process of Ga and Ge follows the kinetic law of "shrinking of unreacted core" , mainly influenced by leaching temperature, concentration of sulfuric acid and leaching time, also being controlled by interface chemical reaction.

  16. Review of Alternative Management Options of Vegetable Crop Residues to Reduce Nitrate Leaching in Intensive Vegetable Rotations

    Directory of Open Access Journals (Sweden)

    Laura Agneessens

    2014-12-01

    Full Text Available Vegetable crop residues take a particular position relative to arable crops due to often large amounts of biomass with a N content up to 200 kg N ha−1 left behind on the field. An important amount of vegetable crops are harvested during late autumn and despite decreasing soil temperatures during autumn, high rates of N mineralization and nitrification still occur. Vegetable crop residues may lead to considerable N losses through leaching during winter and pose a threat to meeting water quality objectives. However, at the same time vegetable crop residues are a vital link in closing the nutrient and organic matter cycle of soils. Appropriate and sustainable management is needed to harness the full potential of vegetable crop residues. Two fundamentally different crop residue management strategies to reduce N losses during winter in intensive vegetable rotations are reviewed, namely (i on-field management options and modifications to crop rotations and (ii removal of crop residues, followed by a useful and profitable application.

  17. The rapid and precise determination of noble metals in matte-leach residues by atomic-absorption spectrophotometry

    International Nuclear Information System (INIS)

    A method is proposed for the rapid analysis of platinum-group metals and gold in matte-leach residues. So that the precision of the atomic-absorption measurement is ensured, many measurements are taken (a chart recorder being used) and the calculation is done on a computer. The dissolution of samples was investigated and optimized. Iridium, which is usually present as a minor constituent, is treated on a separate aliquot portion that is concentrated before measurement. The precision of the method ranges from 0,5 per cent for platinum to 2,3 per cent for iridium

  18. Leaching behavior of residues from mass burn and refuse derived fuel incinerators

    International Nuclear Information System (INIS)

    This paper reports on ashes from refuse derived fuel and mass burn plants that were subjected to batch and column tests to examine leaching behavior. The ash streams were fly and mixed ash from the mass burn plant, and fly, bottom and mixed ash from the RDF plant. The batch tests included sequential extractions with deionized water and extractions under pH control. For the batch pH experiments, the shapes of the lead solubility curves were remarkably similar for all ashes studied, exhibiting a minimum solubility near pH 9. In the column tests with water as the leaching fluid, leachate concentrations of many metals decreased rapidly near the start and then remained at low levels. Tracer tests on the columns showed that columns packed in the same manner can have much different residence time distributions. Batch extractions leached greater quantities of metals from the ashes than column tests. For both greater quantities of metals from the ashes than column tests. For both batch and column tests, pH had a major effect on leaching of metals

  19. Stabilization of APC residues from waste incineration with ferrous sulfate on a semi-industrial scale

    DEFF Research Database (Denmark)

    Lundtorp, Kasper; Jensen, Dorthe Lærke; Christensen, Thomas Højlund

    2002-01-01

    A stabilization method for air pollution control (APC) residues from municipal solid waste incineration (MSWI) involving mixing of the residue with water and FeSO4 has been demonstrated on a semi-industrial scale on three types of APC residues: a semidy (SD) APC residue, a fly ash (FA), and an FA...

  20. Use of fly ash, phosphogypsum and red mud as a liner material for the disposal of hazardous zinc leach residue waste.

    Science.gov (United States)

    Coruh, Semra; Ergun, Osman Nuri

    2010-01-15

    Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The release of large quantities of heavy metals into the environment has resulted in a number of environmental problems. The present study investigated the safe disposal of the zinc leach residue waste using industrial residues such as fly ash, phosphogypsum and red mud. In the study, leachability of heavy metals from the zinc leach residue has been evaluated by mine water leaching procedure (MWLP) and toxicity characteristic leaching procedure (TCLP). Zinc removal from leachate was studied using fly ash, phosphogypsum and red mud. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudo-second-order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudo-second-order kinetic was the best fit kinetic model for the experimental data. The results show that addition of fly ash, phosphogypsum and red mud to the zinc leach residue drastically reduces the heavy metal content in the leachate and could be used as liner materials.

  1. 氧压酸浸处理锌焙砂中浸渣的新工艺研究%Research on Oxidizing Pressure Leaching the Residues from the Neutral Leaching Process

    Institute of Scientific and Technical Information of China (English)

    张向阳; 王吉坤; 巨佳; 徐静; 谢红艳; 贺山明

    2012-01-01

    Zinc calcine leaching process by three-stage, there are neutral leaching-low acid leaching-high acid leaching. Iron would be leaching into the solution in the process of acid leaching which would increase the difficulty of removing iron before electro-deposition. In this paper, the traditional zinc hydrometallurgical and oxygen pressure leaching were combined, the effect of oxygen pressure, concentration of sulfuric acid, temperature, leaching time, mineral particles size, liquor/solid ratio and amount dispersing agentwere found out from the research on oxidizing pressure leaching the residues from the neutral leaching process. The results showed thatoxidizing pressure leaching have good economic benefit and social effect. It is not only improve Zn leaching rate( over 98% ) , reduce Fe leaching rate( low 50% ) , shorten pro- duction cycle and reduction in production costs, but also environment friendly and raising resource utilization. So as to simplify process and save energymeanwhile it can offered reference for industrial study in future.%锌焙砂一般采用中性-低酸-高酸三段浸出工序,该工艺在酸浸出中浸渣的过程中,铁也大量浸出进入到溶液中,加重了净化电积前除铁的负担。通过将传统锌湿法冶金工艺与氧压酸浸新工艺相结合,研究了氧压酸浸处理中浸渣的氧气压力、硫酸浓度、温度、浸出时间、粒度、液固比和分散剂等相关因素的影响。实验结果表明该工艺不仅提高了锌的浸出率(〉98%),降低了铁的浸出率(〈50%),缩短了生产周期,降低了生产成本,具有良好的经济效益;而且还具有环境友好和资源利用率高等优点,实现了简化工艺和节能减排的目的,为工业化生产提供了参考.

  2. 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

    2016-11-01

    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. PMID:27322901

  3. Leaching of hydrophobic Cu and Zn from discarded marine antifouling paint residues: Evidence for transchelation of metal pyrithiones

    International Nuclear Information System (INIS)

    Leaching of Cu and Zn from a composite of discarded antifouling paint residues ([Cu] = 288 mg g-1; [Zn] = 96 mg g-1) into natural sea water has been studied over a period of 75 h. Total Cu and Zn were released according to a pseudo first-order reaction, with rate constants on the order of 0.3 and 2.5 (mg L-1)-1 h-1, respectively, and final concentrations equivalent to the dissolution of about 8 and 2% of respective concentrations in the composite. Time-distributions of hydrophobic metals, determined by solid phase extraction-methanol elution, were more complex. Net release of hydrophobic Cu was greater in the absence of light than under a sequence of light-dark cycles; however, hydrophobic Zn release was not detected under the former conditions but contributed up to 50% of total aqueous Zn when light was present. These observations are interpreted in terms of the relative thermodynamic and photolytic stabilities of biocidal pyrithione complexes. - Hydrophobic Cu and Zn leached from antifouling paint particles into sea water appear to be pyrithione complexes.

  4. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    International Nuclear Information System (INIS)

    Highlights: • Ash was sampled at 10 different points of the boiler of a waste-to-energy plant. • Samples were analysed for the chemical composition, PCDD/F and leaching behaviour. • Enrichment trends of elements were investigated in relation to boiler conditions. • No significant differences were found between boiler ash samples. - Abstract: The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits

  5. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark); Boldrin, A. [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark); Jansson, S. [Umeå University, Department of Chemistry, Umeå SE-901 87 (Sweden); Lundtorp, K. [Babcock and Wilcox Vølund A/S, Göteborg (Sweden); Fruergaard Astrup, T. [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark)

    2014-04-01

    Highlights: • Ash was sampled at 10 different points of the boiler of a waste-to-energy plant. • Samples were analysed for the chemical composition, PCDD/F and leaching behaviour. • Enrichment trends of elements were investigated in relation to boiler conditions. • No significant differences were found between boiler ash samples. - Abstract: The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits.

  6. Optimization of lime addition in a dry air pollution control device; Optimerad rening av HCl och SO{sub 2} med minskade kalktillsatser vid torr roeasrening

    Energy Technology Data Exchange (ETDEWEB)

    Wikstroem-Blomqvist, Evalena; Samuelsson, Jessica; Ohlsson, Anna

    2006-12-15

    The focus of this project is to optimize the absorption of hydrochloric acid (HCl) and sulphuric acid (SO{sub 2}) in a dry air pollution control device system connected to a waste combustor. A significant amount of absorbent are generally added into the processes to achieve an efficient cleaning of the flue gas. Reduced absorbent consumption has double benefits on the operative expenses due to decreased purchase and landfilling costs. The objective was to study the affect of flue gas temperature and moisture, (relative humidity, RH), on the efficiency of HCl and SO{sub 2} absorption on hydrated lime. Additionally, the efficiency of a pre-treated hydrated lime with larger specific surface and pore volume was investigated. The measuring campaign was conducted on the 20 MW fluidized bed waste incinerator own by Boraas Energi och Miljoe AB in Sweden. Results from 26 experimental days with normal hydrated lime showed a positive correlation between the efficiency of the lime and RH in the flue gas. Four levels of RH between 3.28% to 4.84% were tested. The levels were adjusted by lowering the flue gas temperature and/or by adding water to the waste fuel. The smallest effect where achieved by solely adding water to the waste fuel. RH increased solely to 3.62% and the amount of lime consumption was reduced with only 5% compare to normal condition. By lowering the flue gas temperature 10 deg C to 143 deg C, RH increased to 4.06% and the amount of lime added was reduced with 13%. The largest impact was found when both the flue gas temperature and the moisture content were changed. At those process conditions RH reach 4.84 % and the usage of lime were reduced with 26%. Additional 12 experimental days were conducted to evaluate the efficiency of a pretreated hydrated lime with larger specific surface and pore volume. The results showed that the surface enlarged absorbent was almost twice as effective as the normal hydrated lime. Moreover, the results indicated an equal

  7. Nitrógeno residual y lixiviado del fertilizante en el sistema suelo-planta-zeolitas Residual and leached nitrogen in soil plant zeolite systems

    Directory of Open Access Journals (Sweden)

    Gabriela Civeira

    2011-12-01

    mineralización de nitrógeno y la retención de humedad. El mayor nivel de N absorbido en NZ1 se correspondió con un descenso en el N residual significativamente inferior al tratamiento N mientras que el N lixiviado resultó similar. En cambio, cuando la dosis de zeolitas fue mayor (NZ2, el nivel de N absorbido por el maíz fue similar al del tratamiento N, mientras que el N lixiviado se incrementó significativamente respecto de los tratamientos N y NZ1 evidenciando una liberación más tardía del N a la solución del suelo. Estos resultados sugieren que la sincronización entre el patrón de liberación de N del sistema suelo-fertilizante-zeolita y el de absorción del maíz dependió de la dosis de zeolita que acompañó al fertilizante. Mientras que en NZ1 dicha sincronización mejoró la performance del fertilizante, en el tratamiento NZ2 el N retenido por las zeolitas no estuvo disponible para el maíz, siendo detectado como lixiviado al fin del experimento.The N use efficiency in agroecosystems is considered low mainly because of N losses by processes such as nitrate leaching. These losses could be mitigated by incorporating natural zeolites to the N fertilizer formulations. The main objective of this study was to evaluate the effect of natural zeolites additions to formulations with N fertilizers on the contents of residual N and leached N in a soil under maize crop. The hypothesis of this study was that zeolite addition to N fertilizer could reduce the residual and leached N levels but could also affect the plant N availability. A greenhouse experiment was conducted under controlled conditions from February to April 2009. Corn was planted (Zea mays L. in pots which were maintained at field capacity. Zeolite and nitrogen fertilizer (Urea [(NH22CO], solid granules, 46-0-0 were added together as a dry physical mixture, at the beginning of the experiment. The treatments were T: control, Z1: 120 kg ha-1 zeolite, Z2: 200 kg ha-1 zeolite, N: 200 kg N ha-1, NZ1: 120 kg ha

  8. Residual Sorption and leaching of the herbicide diuron following de-oiled two-phase olive mill waste addition to soil

    International Nuclear Information System (INIS)

    The residual sorption, desorption, degradation, and leaching of the herbicide diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) a herbicide widely used in olive groves, was studied following the addition to soils of de oiled two-phase olive mill waste (DTPOMW). Field experiments were conducted on an olive grove soil amended over seven years with DTPOMW. (Author)

  9. To what extent can China’s near-term air pollution control policy protect air quality and human health? A case study of the Pearl River Delta region

    International Nuclear Information System (INIS)

    Following a series of extreme air pollution events, the Chinese government released the Air Pollution Prevention and Control Action Plan in 2013 (China’s State Council 2013). The Action Plan sets clear goals for key regions (i.e. cities above the prefecture level, Beijing-Tianjin-Hebei Province, the Yangtze River Delta and the Pearl River Delta) and establishes near-term control efforts for the next five years. However, the extent to which the Action Plan can direct local governments’ activities on air pollution control remains unknown. Here we seek to evaluate the air quality improvement and associated health benefits achievable under the Action Plan in the Pearl River Delta (PRD) area from 2012 to 2017. Measure-by-measure quantification results show that the Action Plan would promise effective emissions reductions of 34% of SO2, 28% of NOx, 26% of PM2.5 (particulate matter less than 2.5 μm in diameter), and 10% of VOCs (volatile organic compounds). These emissions abatements would lower the PM2.5 concentration by 17%, surpassing the 15% target established in the Action Plan, thereby avoiding more than 2900 deaths and 4300 hospital admissions annually. We expect the implementation of the Action Plan in the PRD would be productive; the anticipated impacts, however, fall short of the goal of protecting the health of local residents, as there are still more than 33 million people living in places where the annual mean ambient PM2.5 concentrations are greater than 35 μg m−3, the interim target-3 of the World Health Organization (WHO). We therefore propose the next steps for air pollution control that are important not only for the PRD but also for all other regions of China as they develop and implement effective air pollution control policies. (letter)

  10. To what extent can China’s near-term air pollution control policy protect air quality and human health? A case study of the Pearl River Delta region

    Science.gov (United States)

    Jiang, Xujia; Hong, Chaopeng; Zheng, Yixuan; Zheng, Bo; Guan, Dabo; Gouldson, Andy; Zhang, Qiang; He, Kebin

    2015-10-01

    Following a series of extreme air pollution events, the Chinese government released the Air Pollution Prevention and Control Action Plan in 2013 (China’s State Council 2013). The Action Plan sets clear goals for key regions (i.e. cities above the prefecture level, Beijing-Tianjin-Hebei Province, the Yangtze River Delta and the Pearl River Delta) and establishes near-term control efforts for the next five years. However, the extent to which the Action Plan can direct local governments’ activities on air pollution control remains unknown. Here we seek to evaluate the air quality improvement and associated health benefits achievable under the Action Plan in the Pearl River Delta (PRD) area from 2012 to 2017. Measure-by-measure quantification results show that the Action Plan would promise effective emissions reductions of 34% of SO2, 28% of NOx, 26% of PM2.5 (particulate matter less than 2.5 μm in diameter), and 10% of VOCs (volatile organic compounds). These emissions abatements would lower the PM2.5 concentration by 17%, surpassing the 15% target established in the Action Plan, thereby avoiding more than 2900 deaths and 4300 hospital admissions annually. We expect the implementation of the Action Plan in the PRD would be productive; the anticipated impacts, however, fall short of the goal of protecting the health of local residents, as there are still more than 33 million people living in places where the annual mean ambient PM2.5 concentrations are greater than 35 μg m-3, the interim target-3 of the World Health Organization (WHO). We therefore propose the next steps for air pollution control that are important not only for the PRD but also for all other regions of China as they develop and implement effective air pollution control policies.

  11. Box-Behnken Design Application to Study Leaching of Pyrolusite from Manganese Mining Residue Using Olive Mill Wastewater as Reductant

    Science.gov (United States)

    Alaoui, Abdallah; El Kacemi, K.; El Ass, K.; Kitane, S.; El Bouzidi, S.

    2015-05-01

    The leaching capacity of olive mill wastewater (OMW) for pyrolusite mine tailings (MnO2) was evaluated using the Box-Behnken experimental design of response surface methodology. The selected test parameters include the concentration of sulfuric acid, the OMW dosage chemical oxygen demand (COD), the solid/liquid ratio S/ L, and particle size. It was determined that the MnO2 dissolution increased with an increase in the sulfuric acid concentration and the OMW dosage, and with a decrease in the solid/liquid ratio. The particle size does not have significant influence on the manganese recovery. A quadratic polynomial model has been developed to predict the amount of manganese extraction from pyrolusite for other operating conditions that were not directly tested. The leaching ability was evaluated based on manganese recovery (Mn%) and the removal capability of chemical oxygen demand (COD%). The predicted values for the responses agreed well with experimental values; R 2 (correlation coefficient) values for Mn% and COD% were 0.9602 and 0.9687, respectively. Within the design space, the optimum conditions for the lixiviation of MnO2 in terms of manganese recovery and COD removal were established and include [H2SO4] of 3 mol L-1, OMW in range of 23 g L-1 to 25 g L-1 COD, and pulp density in range of 90 g L-1 to 100 g L-1. Under these conditions, the response values generated by the model are Mn% ˜49% and COD% >40%. These values show good agreement with those obtained in the validation test. This study has demonstrated that it is possible to use the olive mill wastewater as a reductant agent to recover manganese from a pyrolusite mining residue.

  12. Analysis of the leaching behavior of elements from coal combustion residues for better management.

    Science.gov (United States)

    Kumar, Ashvani; Samadder, S R

    2015-06-01

    In this study, fly ash, pond ash, bottom ash, slurry ash, raw water, pond water, and slurry samples were collected from Bokaro Thermal Power Plant, Bokaro, Jharkhand, India, and studied for the leachability of different elements by acid digestion and shake test at different liquid to solid (L/S) ratios. The raw water, pond water, slurry water, and leachates of acid digestion and shake tests were analyzed for the elements sodium (Na), potassium (K), calcium (Ca), iron (Fe), copper (Cu), cobalt (Co), manganese (Mn), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr). Shake test results confirmed that the water got saturated when the L/S ratio was equal to or above 10, indicating no further increase in concentration of elements at the L/S ratio of 10. Leaching behavior of Na from pond ash was not understood in the present study. In the study, the chemical composition showed that all the four types of ashes contain a small fraction of CaO (about 0.37 to 0.90 % by weight) and very high contents of SiO2 (about 55.14 to 58.34 % by weight) and Al2O3 (about 29.44 to 32.81 % by weight) that are the major composition of Portland cement. The study will help to understand the leachability potential of harmful elements present in fly ash, pond ash, bottom ash, and slurry ash under natural conditions and to take regulatory measures to protect the surface water, groundwater, and soil environment. PMID:26002341

  13. Geochemical modeling and assessment of leaching from carbonated municipal solid waste incinerator (MSWI) fly ash.

    Science.gov (United States)

    Wang, Lei; Chen, Qi; Jamro, Imtiaz Ali; Li, Rundong; Li, Yanlong; Li, Shaobai; Luan, Jingde

    2016-06-01

    Municipal solid waste incinerator (MSWI) fly ashes are characterized by high calcium oxide (CaO) content. Carbon dioxide (CO2) adsorption by MSWI fly ash was discussed based on thermogravimetry (TG)/differential thermal analysis (DTA), minerology analysis, and adapting the Stenoir equation. TG/DTA analysis showed that the weight gain of the fly ash below 440 °C was as high as 5.70 %. An adapted Stenoir equation for MSWI fly ash was discussed. The chloride in MSWI fly ash has a major impact on CO2 adsorption by MSWI fly ash or air pollution control (APC) residues. Geochemical modeling of the critical trace elements copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), and antimony (Sb) before and after carbonation was performed using a thermodynamic equilibrium model for solubility and a surface complexation model for metal sorption. Leaching of critical trace elements was generally found to be strongly dependent on the degree of carbonation attained, and their solubility appeared to be controlled by several minerals. Adsorption on ferrum (Fe) and aluminum (Al) colloids was also responsible for removal of the trace elements Cd, Pb, and Sb. We used Hakanson's potential ecological risk index (HPERI) to evaluate the risk of trace element leaching in general. The results demonstrate that the ecological risk showed a V-shaped dependency on pH; the optimum pH of the carbonated fly ash was found to be 10.3-11, resulting from the optimum carbonation (liquid-to-solid (L/S) ratio = 0.25, carbonation duration = ∼30-48 h). The dataset and modeling results presented here provide a contribution to assessing the leaching behavior of MSWI fly ash under a wide range of conditions. PMID:26965281

  14. Neem seed oil: a potent nitrification inhibitor to control nitrate leaching after incorporation of crop residues

    OpenAIRE

    Opoku, A; Chaves, B; De Neve, Stefaan

    2014-01-01

    The effect of neem seed oil and neem leaf extract as organic nitrification inhibitors (NIs) on the accumulation of NH4+ and NO3-, and nitrification inhibition after incorporation of crop residue was investigated in an incubation experiment. Dicyandiamide (DCD) applications of 15 and 30 kg active ingredient ha(-1) were used as low and high doses of a synthetic NI. Soil samples were amended with 21 g kg(-1) cauliflower leaves and treated with NIs at a rate of 30 kg ha(-1) of neem seed oil, 60 k...

  15. Study on leaching process of lead from acid residue%酸浸渣综合回收浸铅工艺研究

    Institute of Scientific and Technical Information of China (English)

    彭国敏; 俎小凤; 张福元

    2012-01-01

    In allusion to the comprehensive recovery of low-grade lead in acid residue from cyanidation process of golden leaching, salt leaching method was adopted to extract lead in the experimental study. Influences of the factors, such as liquid and solid (L/S) mass ratio, leaching temperature, leaching time, concentration of NaCl, and leaching pH, on leaching ratio of lead were studied through orthogonal experiment. It was found that when L/S mass ratio was 5, leaching tempeture was 333.15 K,mass fraction of NaCl was 30% ,pH =0,and leaching time was 4 h the best average lead leaching rate was 92.05% and relatively standard deviation was 4. 3‰. At room temperature, lead leaching rate also reached 90. 20% and relatively standard deviation was 4.1‰ So salt leaching method is an effective way of lead recovery and gold and silver yield improvement in comprehensive utilization of mines at room temperature.%针对氰化提金工艺酸浸渣中低品位金属铅的综合回收,采用盐浸法对金属铅进行了浸出实验研究,通过正交试验详细考察了浸出液固质量比、浸出温度、氯化钠浓度、浸出pH和浸出时间等因素对浸铅率的影响.结果表明,浸出液固质量比为5、浸出温度为333.15 K、氯化钠质量分数为30%、pH =0、浸出时间为4h的实验条件下,最佳平均浸铅率为92.05%,相对标准偏差RSD=4.3‰;室温下最佳平均浸铅率为90.20%,RSD =4.1‰.因此,酸浸渣常温盐浸提铅是综合利用矿产资源回收铅及提高金、银回收率的有效途径.

  16. Fractionation and leachability of heavy metals from aged and recent Zn metallurgical leach residues from the Três Marias zinc plant (Minas Gerais, Brazil).

    Science.gov (United States)

    Sethurajan, Manivannan; Huguenot, David; Lens, Piet N L; Horn, Heinrich A; Figueiredo, Luiz H A; van Hullebusch, Eric D

    2016-04-01

    Various mineral processing operations to produce pure metals from mineral ores generate sludges, residues, and other unwanted by-products/wastes. As a general practice, these wastes are either stored in a reservoir or disposed in the surrounding of mining/smelting areas, which might cause adverse environmental impacts. Therefore, it is important to understand the various characteristics like heavy metal leaching features and potential toxicity of these metallurgical wastes. In this study, zinc plant leach residues (ZLRs) were collected from a currently operating Zn metallurgical industry located in Minas Gerais (Brazil) and investigated for their potential toxicity, fractionation, and leachability. Three different ZLR samples (ZLR1, ZLR2, and ZLR3) were collected, based on their age of production and deposition. They mainly consisted of Fe (6-11.5 %), Zn (2.5 to 5.0 %), and Pb (1.5 to 2.5 %) and minor concentrations of Al, Cd, Cu, and Mn, depending on the sample age. Toxicity Characteristic Leaching Procedure (TCLP) results revealed that these wastes are hazardous for the environment. Accelerated Community Bureau of Reference (BCR) sequential extraction clearly showed that potentially toxic heavy metals such as Cd, Cu, Pb, and Zn can be released into the environment in high quantities under mild acidic conditions. The results of the liquid-solid partitioning as a function of pH showed that pH plays an important role in the leachability of metals from these residues. At low pH (pH 2.5), high concentrations of metals can be leached: 67, 25, and 7 % of Zn can be leached from leach residues ZLR1, ZLR2, and ZLR3, respectively. The release of metals decreased with increasing pH. Geochemical modeling of the pH-dependent leaching was also performed to determine which geochemical process controls the leachability/solubility of the heavy metals. This study showed that the studied ZLRs contain significant concentrations of non-residual extractable fractions of Zn and can

  17. Amelioration of bauxite residue sand by intermittent additions of nitrogen fertiliser and leaching fractions: The effect on growth of kikuyu grass and fate of applied nutrients.

    Science.gov (United States)

    Kaur, Navjot; Phillips, Ian; Fey, Martin V

    2016-04-15

    Bauxite residue, a waste product of aluminium processing operations is characterised by high pH, salinity and exchangeable sodium which hinders sustainable plant growth. The aim of this study was to investigate the uptake form, optimum application rate and timing of nitrogen fertiliser to improve bauxite residue characteristics for plant growth. Kikuyu grass was grown in plastic columns filled with residue sand/carbonated residue mud mixture (20:1) previously amended with gypsum, phosphoric acid and basal nutrients. The experiment was set up as a 4×4 factorial design comprising four levels of applied nitrogen (N) fertiliser (0, 3, 6 and 12mgNkg(-1) residue) and four frequencies of leaching (16, 8 and 4day intervals). We hypothesised that the use of ammonium sulfate fertiliser would increase retention of N within the rhizosphere thereby encouraging more efficient fertiliser use. We found that N uptake by kikuyu grass was enhanced due to leaching of excess salts and alkalinity from the residue profile. It was also concluded that biomass production and associated N uptake by kikuyu grass grown in residue is dependent on the type of fertiliser used.

  18. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant.

    Science.gov (United States)

    Allegrini, E; Boldrin, A; Jansson, S; Lundtorp, K; Fruergaard Astrup, T

    2014-04-15

    The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits. PMID:24565930

  19. Impact of long-term organic residue recycling in agriculture on soil solution composition and trace metal leaching in soils.

    Science.gov (United States)

    Cambier, Philippe; Pot, Valérie; Mercier, Vincent; Michaud, Aurélia; Benoit, Pierre; Revallier, Agathe; Houot, Sabine

    2014-11-15

    Recycling composted organic residues in agriculture can reduce the need of mineral fertilizers and improve the physicochemical and biological properties of cultivated soils. However, some trace elements may accumulate in soils following repeated applications and impact other compartments of the agrosystems. This study aims at evaluating the long-term impact of such practices on the composition of soil leaching water, especially on trace metal concentrations. The field experiment QualiAgro started in 1998 on typical loess Luvisol of the Paris Basin, with a maize-wheat crop succession and five modalities: spreading of three different urban waste composts, farmyard manure (FYM), and no organic amendment (CTR). Inputs of trace metals have been close to regulatory limits, but supplies of organic matter and nitrogen overpassed common practices. Soil solutions were collected from wick lysimeters at 45 and 100 cm in one plot for each modality, during two drainage periods after the last spreading. Despite wide temporal variations, a significant effect of treatments on major solutes appears at 45 cm: DOC, Ca, K, Mg, Na, nitrate, sulphate and chloride concentrations were higher in most amended plots compared to CTR. Cu concentrations were also significantly higher in leachates of amended plots compared to CTR, whereas no clear effect emerged for Zn. The influence of amendments on solute concentrations appeared weaker at 1 m than at 45 cm, but still significant and positive for major anions and DOC. Average concentrations of Cu and Zn at 1m depth lied in the ranges [2.5; 3.8] and [2.5; 10.5 μg/L], respectively, with values slightly higher for plots amended with sewage sludge compost or FYM than for CTR. However, leaching of both metals was less than 1% of their respective inputs through organic amendments. For Cd, most values were amended plots, in spite of increased soil organic matter, factor of metal retention. Indeed, DOC, also increased by amendments, favours the

  20. Kinetic modeling of thermal decomposition of zinc ferrite from neutral leach residues based on stochastic geometric model

    Energy Technology Data Exchange (ETDEWEB)

    Janković, Bojan, E-mail: bojanjan@ffh.bg.ac.rs [Faculty of Physical Chemistry, Department for Dynamics and Matter Structure, University of Belgrade, Studentski trg 12-16, P.O. Box 137, 11001 Belgrade (Serbia); Stopić, Srećko; Güven, Aybars; Friedrich, Bernd [IME Process Metallurgy and Metal Recycling, RWTH Aachen University, Aachen (Germany)

    2014-05-01

    The stochastic geometric model was applied to kinetic modeling the complex process of thermal decomposition of zinc ferrite from neutral leach residues, at different operating temperatures (600 °C, 750 °C, 950 °C and 1150 °C). Based on functional dependence of Avrami's constant (n) in a function of the effective activation energy (E{sub a}), it was found that at T>950 °C, the crystallization process takes place in autocatalytic stage, under the conditions where the rate of nucleation rapidly increases. It was established that the high nucleation rate can be attributed to formation of both Zn and Fe rich regions which provide a high number of heterogeneous nucleation sites. Based on the obtained final shape of the particles, it was found a strong presence of zinc, iron (present only in the form of Fe{sub 3}O{sub 4} (magnetite)), magnesium (in the form of Mg{sub 2}Si{sub 2}O{sub 6}), and also lead oxides. Thermodynamic analysis showed that the decomposition depends on the introduction of heat, and exerts a positive value of the Gibbs free energy of activation. Such a feature was expected since the ferrite system has been submitted to a forced decomposition and volatilization reactions. - Highlights: • Thermo-chemical investigations. • Autocatalytic stage of process, where the rate of nucleation rapidly increases. • Iron is present in the form of Fe{sub 3}O{sub 4} (magnetite). • The possibility of preparing of the nanosized magnetic particles. • Final product which underwent decomposition has the magnetic properties.

  1. Highlights of the EPA innovative regulatory strategies workshop: Market-based incentives and other innovations for air pollution control. Summary of workshop discussion sessions. Held in Washington, DC on January 15-17, 1992

    International Nuclear Information System (INIS)

    The Clean Air Act Amendments of 1990 allow, and in some cases require, States to adopt market-based strategies or other innovative types of air pollution control. The U.S. Environmental Protection Agency's (EPA's) innovative regulatory strategies program seeks to encourage and facilitate, as appropriate, the development, demonstration, and implementation of a wide range of innovative regulatory air pollution programs, including market-based, informational, and pollution prevention approaches. The 3-day national workshop, attended by over two hundred people from Federal, State, and local agencies, industry, environmental and public interest groups, and the academic community highlighted issues associated with a variety of innovative, market-based strategies which are currently being developed or used by State and local authorities around the country

  2. Publication of expert institutions in the field of air pollution control according to DIN EN ISO/IEC 17025 or with comparable competence; Bekanntgabe sachverstaendiger Stellen im Bereich des Immissionsschutzes nach DIN EN ISO/IEC 17025 oder vergleichbarer Kompetenzfeststellungen

    Energy Technology Data Exchange (ETDEWEB)

    Eickhoff, W. [Hessisches Landesamt fuer Umwelt und Geologie, Kassel (Germany)

    2002-07-01

    According to the decision of the LAI (Laenderausschuss fuer Immissionsschutz - Committee for Air Pollution Control of the German States) of October 2000, expert institutions must prove their competence in order to be listed in the experts list. The contribution describes the procedure and some of the modifications required by recent legislation. [German] Entsprechend den vom Laenderausschuss fuer Immissionsschutz (LAI) im Oktober 2000 beschlossenen Richtlinien fuer die Bekanntgabe und Zulassung von sachverstaendigen Stellen im Bereich des Immissionsschutzes muessen die betreffenden Stellen vor einer Bekanntgabe ihre Kompetenz nachgewiesen haben und damit bestimmte Anforderungen in Bezug auf ein existierendes Qualitaetssicherungssystem erfuellt haben. Die Ueberpruefung der Anforderungen kann entweder im Rahmen eines Akkreditierungsverfahrens durch ein evaluiertes Akkreditierungssystem oder im Rahmen des Bekanntgabeverfahrens durch die nach Landesrecht zustaendige Behoerde erfolgen. Der Vortrag beschreibt die Vorgehensweise und sich aufgrund der aktuellen Regelungen ergebende Neuerungen des Verfahrens. (orig.)

  3. Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles

    Directory of Open Access Journals (Sweden)

    Canan Bural

    2011-08-01

    Full Text Available OBJECTIVES: Residual methyl methacrylate (MMA may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r on in vitro cytotoxicity of L-929 fibroblasts. MATERIAL AND METHODS: A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1 at 74ºC for 9 h, (2 at 74ºC for 9 h and terminal boiling (at 100ºC for 30 min, (3 at 74ºC for 9 h and terminal boiling for 3 h, (4 at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl-3,4-tetrazolium]bis(4-methoxy-6-nitrobenzenesulphonic acid assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05. RESULTS: [MMA]r was significantly (p<0.001 higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01 lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05 for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days. CONCLUSION: Due to reduction of leaching residual MMA concentrations, use of terminal boiling in

  4. Mobility of as, Cu, Cr, and Zn from tailings covered with sealing materials using alkaline industrial residues: a comparison between two leaching methods.

    Science.gov (United States)

    Jia, Yu; Maurice, Christian; Öhlander, Björn

    2016-01-01

    Different alkaline residue materials (fly ash, green liquor dregs, and lime mud) generated from the pulp and paper industry as sealing materials were evaluated to cover aged mine waste tailings (<1% sulfur content, primarily pyrite). The mobility of four selected trace elements (Cr, Cu, Zn, and As) was compared based on batch and column leaching studies to assess the effectiveness of these alkaline materials as sealing agents. Based on the leaching results, Cr, Cu, and Zn were immobilized by the alkaline amendments. In the amended tailings in the batch system only As dramatically exceeded the limit values at L/S 10 L/kg. The leaching results showed similar patterns to the batch results, though leached Cr, Cu, and Zn showed higher levels in the column tests than in the batch tests. However, when the columns were compared with the batches, the trend for Cu was opposite for the unamended tailings. By contrast, both batch and column results showed that the amendment caused mobilization of As compared with the unamended tailings in the ash-amended tailings. The amount of As released was greatest in the ash column and decreased from the dregs to the lime columns. The leaching of As at high levels can be a potential problem whenever alkaline materials (especially for fly ash) are used as sealing materials over tailings. The column test was considered by the authors to be a more informative method in remediation of the aged tailings with low sulfur content, since it mimics better actual situation in a field. PMID:26330323

  5. Heavy metal leaching from aerobic and anaerobic landfill bioreactors of co-disposed municipal solid waste incineration bottom ash and shredded low-organic residues

    International Nuclear Information System (INIS)

    In this study, heavy metal leaching from aerobic and anaerobic landfill bioreactor test cells for co-disposed municipal solid waste incineration (MSWI) bottom ash and shredded low-organic residues has been investigated. Test cells were operated for 1 year. Heavy metals which were comparatively higher in leachate of aerobic cell were copper (Cu), lead (Pb), boron (B), zinc (Zn), manganese (Mn) and iron (Fe), and those apparently lower were aluminum (Al), arsenic (As), molybdenum (Mo), and vanadium (V). However, no significant release of heavy metals under aerobic conditions was observed compared to anaerobic and control cells. Furthermore, there was no meaningful correlation between oxidation-reduction potential (ORP) and heavy metal concentrations in the leachates although some researchers speculate that aeration may result in excessive heavy metal leaching. No meaningful correlation between dissolved organic carbon (DOC) and leaching of Cu and Pb was another interesting observation. The only heavy metal that exceeded the state discharge limits (10 mg/l, to be enforced after April 2005) in the aerobic cell leachate samples was boron and there was no correlation between boron leaching and ORP. Higher B levels in aerobic cell should be due to comparatively lower pH values in this cell. However, it is anticipated that this slightly increased concentrations of B (maximum 25 mg/l) will not create a risk for bioreactor operation; rather it should be beneficial for long-term stability of the landfill through faster washout. It was concluded that aerobization of landfills of heavy metal rich MSWI bottom ash and shredded residues is possible with no dramatic increase in heavy metals in the leachate

  6. A New Process for Leaching of Silver and Zinc From Zinc-silver Residue%从锌银渣中浸出银、锌新工艺研究

    Institute of Scientific and Technical Information of China (English)

    李辉; 刘凯华; 刘岩; 丛自范

    2014-01-01

    Leaching of zinc and silver from zinc-silver residue in sulfuric acid and hydrochloric acid-magnesium chloride system was studied .Zinc-silver residue was leached first using dilute sulfuric acid . The leaching solution was returned to leach zinc .The leaching residue was leached using HCl-magnesium chloride solution ,silver in leaching solution was replaced by iron plate .Influences of magnesium chloride concentration ,leaching temperature ,leaching time ,ratio between liquid volume and solid mass ,and others fractors on leaching rate of silver and zinc were investigated .The experimental results show that the recovery rate of silver and zinc are 85 .26% and 89 .46% , respectively under the optimum conditions .%研究了用硫酸及盐酸-氯化镁体系从锌银渣中浸出银和锌。先用稀硫酸浸出锌银渣中的部分锌、铁,使银、铅富集在浸出渣中,再硫酸浸出渣用盐酸-氯化镁溶液浸出银、锌,然后用铁板置换回收浸出液中的银。考察了氯化镁浓度、浸出温度、浸出时间、液固体积质量比及其他因素对银浸出率的影响。试验结果表明,在最佳条件下,银回收率为85.26%,锌回收率为89.46%。

  7. Nitrous oxide and N-leaching losses from agricultural soil: Influence of crop residue particle size, quality and placement

    DEFF Research Database (Denmark)

    Ambus, P.; Jensen, E.S.; Robertson, G.P.

    2001-01-01

    Incorporation of crop residues provides a source of readily available C and N, and previous works indicate that farming strategies where crop residues are used for soil fertility purposes may lead to increased emissions of N2O. Information on the importance of different residue management on the ...

  8. 从氧化铜矿氨浸渣中浮选回收银%Recovering Silver from Oxide Copper Ammonia Leaching Residue by Flotation

    Institute of Scientific and Technical Information of China (English)

    毕克俊; 方建军; 张琳; 李国栋

    2016-01-01

    某高碱性含银氧化铜矿氨浸渣含银145.55 g/t。对氨浸渣进行了浮恒回收银的试验,结果表明,采用三粗一扫两精的流程,经过闭路流程试验,可获得达到计价标准的银精矿,其银品位为1999.58 g/t、回收率80.78%。%The content of silver in high alkaline oxide copper leaching residue was 145.55 g/t. The flotation tests for recovering silver from ammonia leaching residue have been carried out. The results show that, adopting a flowsheet of three roughing-one scavenging-two cleaning, a silver concentrate with Ag content of 1999.58 g/t was obtained through the closed circuit process experiments and the recovery of silver was 80.78%, which achieved the valuation standard of silver concentrate.

  9. Etude de la récupération du zinc des résidus de lixiviation Recuperation study of zinc from leaching residues

    Directory of Open Access Journals (Sweden)

    Benarioua Younes

    2013-11-01

    Full Text Available La présente étude a été menée dans le but de valoriser le zinc des résidus de lixiviation. Pour ce but, nous avons retenu la méthode goethite qui présente certains avantages. La concentration d'acide sulfurique, la température et le temps de traitement ceux sont les paramètres choisis lors de ce travail. L'effet de trois paramètres sélectionnés sur la dissolution du zinc des résidus de lixiviation a été étudié. Il est démontré que la teneur en zinc augmente avec l'augmentation des valeurs paramétriques. The present work has been conducted in the objective of valorising the zinc from leaching residues. For this purpose we have retained the goethite method which presented some advantages. The sulfuric acid concentration, temperature and time of treatment are those parameters chosen for this study. The effect of three selected parameters on dissolution of zinc from leaching residues was investigated. It is shown that when values parametric increases the content of zinc increase.

  10. Comprehensive Recovery of Valuable Metals from Cyanide Leach Residue%河南某氰化尾渣中有价金属的综合回收

    Institute of Scientific and Technical Information of China (English)

    梁冠杰

    2001-01-01

    河南某矿山提取金后的氰化尾渣中含有铜、铅、银等有价金属元素,为了充分合理利用矿产资源,变废为宝,对该氰化尾渣进行了可选性研究。试验表明:利用混合药剂LD浮选,可获得铜精矿含铜21.82%,回收率96.58%;铅精矿含铅58.20%,回收率74.83%的良好指标,显现了较好的经济效益和社会效益。%There are some valuable metals such as copper,lead and silver in the cyanide leach residue of a gold mine in Henan province.A simple flowsheet by using a mixed collector LD is adopted in this experiment to research comprehensive utilization of the cyanide leach residue containing copper,lead and silver.It can gain a copper concentrate which grade is 21.82% Cu and total recovery is 96.58%.A lead concentrate which grade is 58.20% Pb and total recovery is 74.83% has been obtained.This technology has been popularized and good economic and societal gain has been obtained.

  11. Air Pollution Control in Japan and Its Signiifcance for China%日本治理大气污染的主要做法及其启示

    Institute of Scientific and Technical Information of China (English)

    黄锦龙

    2013-01-01

    The paper introduces the air quality monitoring system of Japan and its air quality releasing system. Meanwhile, it analyses the concrete methods and measures taken by Japanese government on air pollution control, such as, adhering to the principle of environment improvement, enforcing the environment protection law strictly, enhancing the technology development, motivating engagement of all citizens, striking a balance between economy growth and environment protection. The successful experience of Japan on pollution control is worth to be shared by Chinese government departments.%通过分析、阐述日本治理人为大气污染源的具体做法和措施,以及介绍日本大气质量监测管理体系和信息发布情况,可以了解到:日本政府坚持污染治理原则,严格执法,加强技术开发,推动全社会共同参与,实现了污染治理和经济增长的同步发展。日本治理大气污染的成功经验,值得借鉴和吸收。

  12. Extraction of toxic and valuable metals from wastewater sludge and ash arising from RECICLAGUA, a treatment plant for residual waters applying the leaching technique

    International Nuclear Information System (INIS)

    Presently work, the technique is applied of having leached using coupled thermostatted columns, the X-ray diffraction for the identification of the atomic and molecular structure of the metals toxic that are present in the residual muds of a treatment plant of water located in the municipality of the Estado de Mexico, RECICLAGUA, likewise the techniques is used of Inductively Coupled Plasma Mass Spectroscopy and X-ray fluorescence analysis for the qualitative analysis. We took samples of residual sludge and incinerated ash of a treatment plant waste water from the industrial corridor Toluca-Lerma RECICLAGUA, located in Lerma, Estado de Mexico. For this study 100 g. of residual of sludge mixed with a solution to 10% of mineral acid or sodium hydroxide according to the case, to adjust the one p H at 2, 5, 7 and 10, bisulfite was added, of 0.3-1.5 g of dodecyl sulfate of sodium and 3.93 g of DTPA (triple V). Diethylene triamine penta acetate. These sludges and ashes were extracted from toxic and valuable metals by means of the leaching technique using coupled thermostated columns that which were designed by Dr. Jaime Vite Torres, it is necessary to make mention that so much the process as the apparatus with those that one worked was patented by him same. With the extraction of these metals, benefits are obtained, mainly of economic type, achieving the decrease of the volume of those wastes that have been generated; as well as the so much use of those residuals, once the metals have been eliminated, as of those residuals, once the metals have been eliminated, as of those liquors, the heavy metals were extracted. It was carried out a quantitative analysis using Icp mass spectroscopy, this way to be able to know the one content of the present metals in the samples before and after of leaching them, these results reported a great quantity of elements. Another of the techniques employees was the analysis by X-ray diffraction that provides an elementary content of the

  13. 湿法炼锌净化渣酸浸的动力学%Acid leaching kinetics of zinc plant purification residue

    Institute of Scientific and Technical Information of China (English)

    李倩; 张宝; 闵小波; 申文前

    2013-01-01

    The leaching processes of zinc plant purification residue in sulfuric acid solution were investigated with respect to the effects of sulfuric acid concentration, reaction temperature, and particle size. A particle size of 75−80 μm was required to leach 99.8%cobalt and 91.97%zinc at 70 °C for 20 min when the sulfuric acid concentration was 100 g/L and the ratio of liquid to solid was 50׃1 (mL/g). The leaching kinetics of zinc plant purification residue in sulfuric acid solution system conformed well to the shrinking core model, and the dissolution rates of cobalt and zinc were found to be controlled by diffusion through a porous product layer. The apparent activation energy values of cobalt and zinc reaction were calculated to be 11.6931 kJ/mol and 6.6894 kJ/mol, respectively, according to the Arrhenius formula equation. The results show that diffusion through the inert particle pores is the leaching kinetics rate-controlling step.%对湿法炼锌净化渣的浸出动力学进行了研究,并探讨了硫酸浓度、反应温度、粒度等对钴、锌浸出率的影响规律。从动力学的角度分析了整个浸出过程,得到优化条件:液固比50:1(mL/g),硫酸浓度100 g/L,反应温度70°C,粒度75~80μm,反应时间20 min。在此优化条件下钴的浸出率为99.8%,锌的浸出率为91.97%。结果表明:在硫酸体系中钴的浸出符合不生成固体产物层的“未反应收缩核”模型。通过 Arrhenius 经验公式求得钴和锌表观反应活化能分别为11.693 kJ/mol和6.6894 kJ/mol,这表明浸出过程受边界层扩散控制。

  14. Thorium, Uranium and Rare Earth Elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas Advanced Materials Plant (LAMP)

    International Nuclear Information System (INIS)

    Full-text: Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6 Bq/ kg) whereas the Th and U concentrations in WLP were determined to be 1952.9 ± 17.6 ppm (7987.4 ± 71.9 Bq/ kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/ kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/ kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/ kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6 % and 4.7 ± 0.1 % respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04 %, 1.6 %, 0.22 % and 0.06 % respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be re

  15. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    Science.gov (United States)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-02-01

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) & 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) &29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  16. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    International Nuclear Information System (INIS)

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted

  17. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    Energy Technology Data Exchange (ETDEWEB)

    AL-Areqi, Wadeeah M., E-mail: walareqi@yahoo.com; Majid, Amran Ab., E-mail: walareqi@yahoo.com; Sarmani, Sukiman, E-mail: walareqi@yahoo.com [Nuclear Science Programme, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi (Malaysia)

    2014-02-12

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  18. Extraction of Zinc from Electric Arc Furnace Dust by Alkaline Leaching Followed by Fusion of the Leaching Residue with Caustic Soda%氢氧化钠浸取-浸取渣熔融法从炼钢厂烟尘中提取锌的研究

    Institute of Scientific and Technical Information of China (English)

    赵由才; R. Stanforth

    2004-01-01

    Extractability of zinc from two types of electric arc furnace (EAF) dusts containing 24.8% and 16.8%of zinc respectively (denoted as Sample A and Sample B) were tested using direct alkaline leaching followed by fusion of the resulting leaching residues with caustic soda. The experimental results show that the extraction of zinc is heavily dependent on the contents of iron in the dusts. The higher iron content, the lower extraction of zinc is obtained. 53% and 38% of zinc can be extracted when both dusts were directly contacted with 5 mol. L-1 NaOH solution for 42 h. The remaining zinc left in the leaching residues, which supposed to be present as zinc ferrites, can be further leached when the residues were fused with caustic soda. Quantitative extraction of zinc can be obtained from the leaching residue of Sample A while only 85% from Sample B. The extractability of zinc from dusts with various contents of iron is compared. The production flowsheet for zinc from the dusts using the process proposed is discussed.

  19. Can air pollutant controls change global warming?

    International Nuclear Information System (INIS)

    Highlights: • Air pollution policies do not affect long-term climate targets. • Reduction of aerosols counteracts a fraction of the reduction of Kyoto forcing. • Air pollution policies may affect the rate of climate change in the short term. • There is no tradeoff between clean air and climate policies. - Abstract: In this paper we analyze the interaction between climate and air pollution policies using the integrated assessment model REMIND coupled to the reduced-form climate model MAGICC. Since overall, aerosols tend to cool the atmosphere, there is a concern that a reduction of pollutant emissions could accelerate global warming and offset the climate benefits of carbon dioxide emission reductions. We investigate scenarios which independently reduce emissions from either large-scale sources, such as power plants, or small-scale sources, such as cooking and heating stoves. Large-scale sources are likely to be easier to control, but their aerosol emissions are characterized by a relatively high sulfur content, which tends to result in atmospheric cooling. Pollution from small-scale sources, by contrast, is characterized by a high share of carbonaceous aerosol, which is an important contributor to global warming. We find that air pollution policies can significantly reduce aerosol emissions when no climate policies are in place. Stringent climate policies lead to a large reduction of fossil fuel use, and therefore result in a concurrent reduction of air pollutant emissions. These reductions partly reduce aerosol masking, thus initially counteracting the reduction of greenhouse gas forcing, however not overcompensating it. If climate policies are in place, air pollution policies have almost no impacts on medium- and long-term radiative forcing. Therefore there is no conflict of objectives between clean air and limiting global warming. We find that the stringency of air pollution policies may influence the rate of global temperature change in the first decade. Afterwards climate change mitigation policies are of greater importance

  20. Urban air pollution control in Peru

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-12-20

    Our central health cost estimate from particulate matter (PM) concentrations in larger Peruvian cities is approximately USD 790 million/year. More than 60 percent of these costs occur in Lima-Callao. Diesel vehicles are the most important emission source. Various abatement actions could yield health benefits of around USD 50 million in 2008 and USD 185 million after 2010. Some of the most important cost effective actions would be an inspection and maintenance (I&M) program for vehicles (planned to start in 2006) and introduction of low sulphur diesel (<50 ppm) from 2010. When low sulphur diesel is available, installing retrofit particle control technology on existing vehicles could be very cost effective. Some actions towards stationary sources could also be cost effective. In addition a mixture of several measures like tax incentives to promote use of gasoline cars at the expense of diesel cars, accelerated scrapping of old, polluting vehicles, ban on the use of some diesel vehicles and import restrictions on used cars could be chosen to yield short and long term air pollution benefits.

  1. Fungal leaching of valuable metals from a power plant residual ash using Penicillium simplicissimum: Evaluation of thermal pretreatment and different bioleaching methods.

    Science.gov (United States)

    Rasoulnia, P; Mousavi, S M; Rastegar, S O; Azargoshasb, H

    2016-06-01

    Each year a tremendous volume of V-Ni rich ashes is produced by fuel oil consuming power plants throughout the world. Recovery of precious metals existing in these ashes is very important from both economic and environmental aspects. The present research was aimed at investigating bioleaching potential of Penicillium simplicissimum for the recovery of metals from power plant residual ash (PPR ash) using different bioleaching methods such as one-step, two-step, and spent-medium bioleaching at 1% (w/v) pulp density. Furthermore, the effects of thermal pretreatment on leaching of V, Ni, and Fe, as major elements present in PPR ash, were studied. Thermal pretreatment at various temperatures removed the carbonaceous and volatile fraction of the ash and affected the fungal growth and metal leachability. The highest extraction yields of V and Ni were achieved for the original PPR ash, using spent-medium bioleaching in which nearly 100% of V and 40% of Ni were extracted. The maximum extraction yield of Fe (48.3%) was obtained for the pretreated PPR ash at 400°C by spent-medium bioleaching. In addition, the fungal growth in pure culture was investigated through measurement of produced organic acids via high performance liquid chromatography (HPLC). Chemical leaching experiments were performed, using commercial organic acids at the same concentrations as those produced under optimum condition of fungal growth (5237ppm citric, 3666ppm gluconic, 1287ppm oxalic and 188ppm malic acid). It was found that in comparison to chemical leaching, bioleaching improved V and Ni recovery up to 19% and 12%, respectively. Moreover, changes in physical and chemical properties as well as morphology of the samples utilizing appropriate analytical methods such as XRF, XRD, FTIR, and FE-SEM were comprehensively investigated. PMID:27095291

  2. 催化型低温等离子体反应器净化废气研究进展%Advances in catalysis non-thermal plasma reactor for air pollution control

    Institute of Scientific and Technical Information of China (English)

    刘跃旭; 王少波; 原培胜; 赵瀛

    2009-01-01

    催化型低温等离子体反应器可有效地提高废气治理的能量效率和净化效果.现有数据表明,在一定能量密度下,催化型低温等离子体反应器比传统低温等离子体反应器能量效率有1.1~12倍的提高,这和污染物种类,反应器构型及催化剂参数有关.本文介绍了反应机理、反应器构型及催化剂参数选择等对反应器性能的影响,并指出今后研究的发展方向.%Catalysis non-thermal plasma reactor has been demonstrated to be effective in improving the energy efficiency and purification for air pollution control. According to the available experimental data, for a given specific energy density, the energy efficiency for gaseous pollutant abatement obtained with catalysis non-thermal plasma reactor could be improved with 1.1-12 times as compared to that of conventional reactors depending on the type of pollutants, reactor geometry and catalyst used. The influences of reaction mechanism, reactor geometry and catalyst parameters on the performance for gaseous pollutant removal are comprehensively discussed, and the further development trend of this technology is proposed.

  3. Desarrollo de un Programa de Simulación de Procesos para el Tratamiento de Emisiones Atmosféricas Development of Simulation Software for the Air Pollution Control Processes

    Directory of Open Access Journals (Sweden)

    S.A. Pérez

    2004-01-01

    Full Text Available Se presenta el desarrollo de un programa para la simulación de procesos asociados al tratamiento de emisiones atmosféricas. El programa creado, denominado SIMTEGUC, utiliza un enfoque modular secuencial para la administración y control del flujo de la información durante la simulación. Fueron desarrollados los siguientes módulos de cálculo: ciclones, filtros de mangas, precipitadores electrostáticos, mezcladores y divisores de corrientes, unidades para el control y promoción de la convergencia en procesos con reciclo, adsorbedores y lavadores de partículas. Todos los módulos desarrollados fueron validados individualmente mediante estudio comparativo con los resultados aportados por la simulación del mismo caso mediante un programa comercial, observándose una desviación menor al 7%. Se concluye que el programa desarrollado entrega buenos resultados y se puede extender su uso a otras áreasThe objective of this research was to develop a software for the simulation of air pollution control processes. The software developed, named SIMTEGUC, uses a modular and sequential approach for the management and control of the information flow during the process simulation. The following simulation units were developed: cyclones, bag filters, electrostatic precipitators, mixers, flow splitters, units for the control and promotion of convergence in recycling processes, absorbers and particle scrubbers. All these units were validated individually through a comparative study of the results obtained from the simulation and the results from a commercial simulation program, with a deviation of less than 7%. It was concluded that the program developed produced good results and could be extended to other areas

  4. 锌浸出渣浮选银的预处理研究%Flotation of Silver by Pretreatment from Zinc Leaching Residue

    Institute of Scientific and Technical Information of China (English)

    张少博; 沈强华; 朱云; 陈雯

    2013-01-01

    在锌精矿的沸腾焙烧过程中,温度高于650℃时,生成的氧化锌及氧化铁结合成铁酸锌,是一种难溶于稀硫酸的铁氧体,全部留在浸出渣中.高温高酸浸出条件控制愈好,铁酸锌被溶解的愈多,硫化锌被破坏的就愈彻底,渣含锌就愈低,金属回收率就愈高,而且有利于银的浮选.针对某冶炼厂湿法炼锌渣,采用高温高酸浸出和浮选的方法回收锌、银,高温高酸浸出液经过除铁得到的溶液返回锌系统回收锌,高温高酸浸出渣经过一次粗选两次精选三次扫选的试验流程,得到了品位达到了2017.45g/t,回收率达到78.44%的银精矿.%The zinc ferrite formed by zinc oxide and iron oxide is generated from the roasting process of zinc concentrate at the temperature of more than 650℃ which is a kind of ferrite insoluble in dilute sulfuric acid,but remaining in the leaching residue. The better control of high temperature and high acid leaching conditions, the more the zinc ferrite was dissolved, the more thoroughly the zinc sulfide was destroyed, the lower the slag containing zinc is and the higher the metal recovery rate is, benefiting the flotation for silver. Directed at the zinc slag hydrometallurgy, using the method of high temperature and high acid leaching and flotation to recovery zinc and silver,the solution obtained from the high temperature and high acid leaching solution by means of dividing iron was returned to zinc system to recover zinc. By adopting the process of one roughing two cleaning three scavenging, the silver concentrate with the grade of 2017.45g/t and the recovery of 78.44% was obtained.

  5. On the ASR and ASR thermal residues characterization of full scale treatment plant.

    Science.gov (United States)

    Mancini, G; Viotti, P; Luciano, A; Fino, D

    2014-02-01

    In order to obtain 85% recycling, several procedures on Automotive Shredder Residue (ASR) could be implemented, such as advanced metal and polymer recovery, mechanical recycling, pyrolysis, the direct use of ASR in the cement industry, and/or the direct use of ASR as a secondary raw material. However, many of these recovery options appear to be limited, due to the possible low acceptability of ASR based products on the market. The recovery of bottom ash and slag after an ASR thermal treatment is an option that is not usually considered in most countries (e.g. Italy) due to the excessive amount of contaminants, especially metals. The purpose of this paper is to provide information on the characteristics of ASR and its full-scale incineration residues. Experiments have been carried out, in two different experimental campaigns, in a full-scale tyre incineration plant specifically modified to treat ASR waste. Detailed analysis of ASR samples and combustion residues were carried out and compared with literature data. On the basis of the analytical results, the slag and bottom ash from the combustion process have been classified as non-hazardous wastes, according to the EU waste acceptance criteria (WAC), and therefore after further tests could be used in future in the construction industry. It has also been concluded that ASR bottom ash (EWC - European Waste Catalogue - code 19 01 12) could be landfilled in SNRHW (stabilized non-reactive hazardous waste) cells or used as raw material for road construction, with or without further treatment for the removal of heavy metals. In the case of fly ash from boiler or Air Pollution Control (APC) residues, it has been found that the Cd, Pb and Zn concentrations exceeded regulatory leaching test limits therefore their removal, or a stabilization process, would be essential prior to landfilling the use of these residues as construction material. PMID:24290536

  6. Alkali Leaching Kinetics of Amorphous Aluminum Hydroxide Mud in Chromium Hydroxide Residue for Aluminium Recovery%铬渣中无定型铝泥碱浸提铝动力学

    Institute of Scientific and Technical Information of China (English)

    田磊; 徐志峰; 李平; 徐红彬; 张懿

    2011-01-01

    以含Cr(OH)3和Al(OH)3的铝泥渣为原料,研究渣中Al(OH)3在343~373 K温度内的碱浸动力学.结果表明,在NaOH溶液初始浓度150g/L、液固比15 mL/g、搅拌转速450 r/min条件下,在浸出达到平衡前,铝浸出率与浸出时间呈良好的线性关系,随温度升高,铝浸出达到平衡所需时间不断缩短;在343~373 K内,铝浸出速率随浸出温度升高不断增大,最终可达94.07%,所得氧化铬产品中氧化铬的含量为98.12%.Cr(OH)3渣中铝浸出反应的表观活化能为62.38 kJ/mol,浸出过程遵循界面化学反应控制的粒径收缩芯模型.%With the aluminum residue containing chromium hydroxide [Cr(OH)3] and aluminum hydroxide [A1(OH)3] as raw material, the alkali leaching kinetics of A1(OH)3 in the residue has been studied in the following conditions: leaching temperature from 343 to 373 K, initial concentration of sodium hydroxide 150 g/L, ratio of liquid to solid 15 mL/g, and agitation speed 450 r/min. The experimental results show that a linear relationship between the leaching rate of aluminum and leaching time exits before the leaching equilibrium. The time consumed for which the leaching of aluminum reaches at the equilibrium is shortened with the increase of leaching temperature. The leaching rate of aluminum is increased with the increase of temperature in 343-373 K, finally the leaching rate of aluminum is 94.07%, leading to the main content of chrome oxide product at 98.12%. The apparent activation energy is determined as 62.38 kJ/mol for the leaching of aluminum. The leaching of aluminum follows the shrinking core model with surface reaction control.

  7. Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

    Science.gov (United States)

    Cara, Irina Gabriela; Trincă, Lucia Carmen; Trofin, Alina Elena; Cazacu, Ana; Ţopa, Denis; Peptu, Cătălina Anişoara; Jităreanu, Gerard

    2015-12-01

    Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

  8. STUDY ON ELECTROWINNING EXTRACTION OF LEAD FROM ZINC OXIDE LEACH RESIDUE OF IRONMAKING DUST%从炼铁烟尘的氧化锌浸出渣中电积提取铅的研究

    Institute of Scientific and Technical Information of China (English)

    邢燕; 吴绍祥

    2013-01-01

    炼铁烟尘经挥发窑处理后得到的窑挥发物的主要成分为氧化锌和氧化铅,本研究以此挥发物提取锌后的浸出渣为试验原料,用碳酸钠将硫酸铅转化为碳酸铅,再用氟硅酸浸出,浸出液电积得到金属铅.氧化锌浸出渣中铅的转化浸出率在96%以上,整个工艺过程无废弃物外排.%The main components of kiln volatiles from the ironmaking smoke and dust treated by volatile kiln are zinc oxide and lead oxide.The study takes the zinc leaching residue of the volatile after the extraction of zinc as raw materials,transfers the lead sulfate into lead carbonate by sodium carbonate,then leaching by fluorosilicic acid,and finally the metal lead can be obtained by leaching solution electrowinning.The transformation of lead in zinc oxide leach residue leaching rate reaches over 96%,and no waste effluent during the whole process.

  9. Divisions S-4 - soil fertility and plant nutrition: residual value of lime and leaching of calcium in a kaolinitic ultisol in the high rainfall tropics

    Energy Technology Data Exchange (ETDEWEB)

    Friesen, D.K.; Juo, A.S.R.; Miller, M.H.

    1982-01-01

    A long-term experiment was conducted on a highly acidic (pH 4.6), coarse-textured Ultisol in the high rainfall region of southeastern Nigeria in order to evaluate the requirement for and residual value of lime (Ca(OH)/sub 2/) to a continuous crop rotation, and to determine the fate of applied Ca in the soil profile. The initial lime rates used were 0, 0.5, 1, 2, and 4 t of Ca(OH)/sub 2/ per hectare. Maize (Zea mays) was planted in the first season and cowpea (Vigna unguiculata) in the second season under a no-tillage, stubble conservation system. Relatively low rates of lime are adequate to sustain yields in a continuous maize-cowpea rotation system. Liming at a rate of 0.5 t/ha maintained maize yield near maximum for 2 years after application. Sustained maize yields for 5 years or more were possible with a lime rate of 2 t/ha. Cowpeas performed well and showed strong tolerance to soil acidity when planted as a late second-season crop after maize without additional fertilizer application. The critical level of exchangeable Al ranged from 25 to 55% depending upon rate of chemical fertilizer as well as cowpea variety used. Leaching losses of Ca from the surface soil during the first 3 years were <0.5 t/ha of Ca(OH)/sub 2/-equivalents in the 0- to 2-t/ha treatments. Exchangeable-Al saturation in all subsoil layers of all treatments 3 years after liming exceeded 40% and soil pH (H/sub 2/O) was <4.3 indicating that lime was leached as neutral Ca salts and had little effect in ameliorating subsoil acidity. 17 references, 5 figures, 5 tables.

  10. Extraction Process for Molybdenum from Ammonia Leaching Residues%从三次氨浸钼渣中碳酸钠氧压浸钼的工艺研究

    Institute of Scientific and Technical Information of China (English)

    彭俊; 沈裕军; 刘强; 钟祥; 何鲁华

    2015-01-01

    采用碳酸钠氧压浸出工艺处理氨浸钼渣,研究了原料预处理、碳酸钠用量、氧分压、浸出液固比、时间、温度、搅拌速度对钼浸出率的影响。结果表明:在碳酸钠加入量为化学反应理论量2.3倍,液固比为3∶1,氧分压0.5 MPa,温度180℃,时间1 h,搅拌速度700 r/min的最佳工艺条件下,钼浸出率可达95%以上。%Technique of leaching molybdenum from ammonia leaching residues by alkaline pressure leaching was presented. The factors influencing the leaching rate of molybdenum, such as pre-treatment of material, addition of Na2CO3, oxygen partial pressure, liquid/solid ratio, leaching time, leaching temperature and stirring speed, were investigated. Results showed that the leaching rate of Mo exceeds 95% under the following optimum conditions with the addition of Na2CO3 at 2.3 times of theoretical amount for chemical reaction, liquid/solid ratio of 3∶1, oxygen partial pressure of 0.5 MPa, leaching at 180 ℃ for 1 h, stirring at speed of 700 r/min.

  11. Extraction Process for Molybdenum from Ammonia Leaching Residues%从三次氨浸钼渣中碳酸钠氧压浸钼的工艺研究

    Institute of Scientific and Technical Information of China (English)

    彭俊; 沈裕军; 刘强; 钟祥; 何鲁华

    2015-01-01

    Technique of leaching molybdenum from ammonia leaching residues by alkaline pressure leaching was presented. The factors influencing the leaching rate of molybdenum, such as pre-treatment of material, addition of Na2CO3, oxygen partial pressure, liquid/solid ratio, leaching time, leaching temperature and stirring speed, were investigated. Results showed that the leaching rate of Mo exceeds 95% under the following optimum conditions with the addition of Na2CO3 at 2.3 times of theoretical amount for chemical reaction, liquid/solid ratio of 3∶1, oxygen partial pressure of 0.5 MPa, leaching at 180 ℃ for 1 h, stirring at speed of 700 r/min.%采用碳酸钠氧压浸出工艺处理氨浸钼渣,研究了原料预处理、碳酸钠用量、氧分压、浸出液固比、时间、温度、搅拌速度对钼浸出率的影响。结果表明:在碳酸钠加入量为化学反应理论量2.3倍,液固比为3∶1,氧分压0.5 MPa,温度180℃,时间1 h,搅拌速度700 r/min的最佳工艺条件下,钼浸出率可达95%以上。

  12. 利用钼酸钙和氨浸渣冶炼钼铁实验研究%Experimental Study on Preparing Ferromolybdenum with Calcium-molybdate and Ammonia Leach Residue

    Institute of Scientific and Technical Information of China (English)

    杨双平; 梁洁旗; 蔡文淼; 孙超; 刘东新; 王磊

    2015-01-01

    With iron concentrate powder as iron⁃addition agent, the industrial residue including ammonia leach residue and calcium⁃molybdate were used in the experiment for preparing ferromolybdenum by direct reduction process. The effect of addition of ammonia leach residue and calcium⁃molybdate on alkalinity, smelting time, metal recovery rate, and smelting temperature was investigated in the tests. It is found that increasing the addition of calcium molybdate can lead to the alkalinity increased and metal recovery rate improved, thus smelting time shortened, while increasing the amount of ammonia leach residue can result in a drop in the smelting temperature. It can be seen that a better result was obtained at the smelting temperature of 1 500 ℃, with alkalinity of 1.2 and the mass ratio of CaMoO4 to ammonia leach residue at 1.5.%以铁精矿粉为供铁剂,使用工业废渣氨浸渣、钼酸钙进行了直接还原冶炼钼铁实验研究,分析了氨浸渣及钼酸钙加入量对碱度、冶炼周期、金属回收率、冶炼温度的影响。结果表明,钼酸钙含量增加,碱度提高,金属回收率上升,冶炼周期随之降低;氨浸渣加入量增加,冶炼温度下降。在1500℃,CaMoO4/氨浸渣质量比1.5,碱度1.2时,冶炼效果较好。

  13. Microbial leaching of marmatite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; QIU Guan-zhou; QIN Wen-qing; ZHANG Yan-sheng

    2006-01-01

    The bioleaching of marmatite in shaken flasks was studied. After leaching for 29 days, the leaching ratio of zinc was 91%.Three kinds of bacteria, mixture-based bacteria, 9K-based bacteria and sulfur-based bacteria were used in marmatite leaching, of which the mixture-based bacteria have the best leaching result while the sulfur-based bacteria have the worst. By analyzing the leaching residue using SEM and EDXA, the marmatite leaching mechanism was discussed.

  14. Measurement of leached hulls

    International Nuclear Information System (INIS)

    Leached hulls are the short lengths of fuel rod cladding and fuel element hardware which constitute a major waste product of a reprocessing plant employing a chop-and-leach head-end process. The small, undissolved fuel residue (0.1 to 1.0% of original fuel content) which is discarded with this waste must be measured for safeguards, material accountability, and process control reasons. This report gives a critical analysis of hull measurement techniques involving the analysis of fission product gamma rays, spontaneous fission neutrons from curium, and delayed neutron activation. Major emphasis is given to the measurement of 2186-keV gamma rays from 144Ce--144Pr. A detailed description of typical leached hull characteristics is presented at the beginning of the report. An extensive review of experience gained from existing hull measurement systems in the United Kingdom, France, Japan, Germany, Italy, and the United States is presented

  15. 硫化砷渣中砷浸出特性研究*%Research of Leaching Characteristics of Arsenic in Arsenic Sulfide Residue under Different pH and Ca/As Ratio Conditions

    Institute of Scientific and Technical Information of China (English)

    张洪; 黄宗凯; 何政兵

    2014-01-01

    Through the horizontal oscillation toxicity characteristic leaching experiment,leaching of arsenic in arsenic sulfide residue under different liquid pH and Ca/As ratio (molar ratio )conditions was studied.The experimental results showed that different pH and Ca/As ratio of the leaching liquid have great influence on As leaching concentration.When pH of the solution was in the 1.01 to 13.12 range,with the increase of pH value of leaching solution,the concentration of As in the leaching solution firstly decreased and then increased.When pH was equal to 1 1 .9 1 ,the concentration of arsenic reached the minimum value of 4.27g/L. When the Ca/As ratio increased,the leaching concentrations of As increased firstly and then decreased. When Ca/As was equal to 1.405,the concentration of arsenic had maximum value of 31.674g/L. Overall,when the Ca/As ratio was in the 0.187 to 5.619 range,by adding CaO,macroeconomic perform-ance is to promote As dissolution from arsenic sulfide residue.%通过水平振荡毒性浸出试验,研究了硫化砷渣在不同的pH值和n(Ca)/n(As)下As的浸出。结果表明:浸出液pH值和n(Ca)/n(As)的不同,会对As的浸出质量浓度产生较大影响,pH在1.01~13.12范围内时,随着pH值的增大,浸出液As的质量浓度先减小后增加,在pH=11.91时,达到最小值4.27 g/L;而随着n(Ca)/n(As)的增加,As的浸出质量浓度先增大后减小,在n(Ca)/n (As)=1.405时出现最大值,As浸出质量浓度为31.674 g/L。但总体来说n(Ca)/n(As)在(0.187~5.619)范围内,加入CaO宏观表现为促进硫化砷渣中As的溶出。

  16. 石棉尾矿酸浸渣填充改性道路沥青的研究%Research on Road Asphalt Filled and Modified with Acid-leaching Residue of Asbestos Tailings

    Institute of Scientific and Technical Information of China (English)

    孙志明; 郑水林; 文明; 吴照洋

    2009-01-01

    The acid-leaching residue of asbestos tailings is silicon slag of asbestos tailings, one kind of solid waste after acid leaching extraction of magnesium. In this experiment, using acid leaching residue of asbestos tailings after calcination as the filler of asphalt modifier, through the test of penetration, ductility, softening point of modified asphalt, the effects of the adding volume and mixing conditions (temperature, time, etc.) of the acid leaching residue on the performance of road asphalt has been studied. The results showed that the appropriate conditions of modified process is that the adding volume of acid leaching residue 6%, mixing temperature 140℃, and heating mixing time 20rain. In this condition, the performance of modified asphalt material, such as high temperature and low temperature performance, temperature sensitivity, and anti-aging property have been significantly improved.%石棉尾矿酸浸渣是石棉尾矿蛇纹石酸浸提取氧化镁后的硅质粉体材料.本实验以煅烧后的石棉尾矿酸浸渣作为道路沥青填充改性剂,通过测定改性沥青的针入度、延度、软化点等指标,研究了酸浸渣填充量、混合控温以及加热混合时间对道路沥青综合性能的影响.结果表明,石棉尾矿酸浸渣填充改性沥青适宜的填充工艺条件为填充量6%,混合控温140℃,加热混合时间20min;在适宜的填充工艺条件下,改性沥青的高温性能、低温性能、高低温稳定性以及抗老化性均得到显著改善或提高.

  17. Coupling leaching of sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    彭鹏; 谢惠琴; 卢立柱

    2004-01-01

    Coupling process of sphalerite concentrate leaching in H2 SO4-HNO3 and tetrachloroethylene extracting of sulfur was investigated. Effects of leaching temperature, leaching time, mass ratio of liquid to solid and tetrachloroethylene addition on zinc leaching processes were examined separately. SEM images of sphalerite concentrate and residues were performed by using JEM-6700F field emission scanning electron microscope. The relationship between the number of recycling and extraction ratio of zinc was studied. The results indicate that 99.6 % zinc is obtained after leaching for 3 h at 85 ℃ and pressure of 0.1 MPa O2, with 20 g sphalerite concentrate in 200 mL leaching solution containing 2.0 mol/L H2SO4 and 0.2 mol/L HNO3, in the presence of 10 mL C2Cl4. The leaching time of zinc is 50% shorter than that in the common leaching. The coupling effect is distinct. The recycled C2Cl4 exerts little influence on extraction ratio of zinc.

  18. Selective reduction process of zinc ferrite and its application in treatment of zinc leaching residues%铁酸锌选择性还原及其在锌浸出渣处理中的应用

    Institute of Scientific and Technical Information of China (English)

    余刚; 彭宁; 周兰; 梁彦杰; 周晓源; 彭兵; 柴立元; 杨志辉

    2015-01-01

    传统湿法炼锌过程产生大量富含有价金属资源的铁酸锌废渣,铁的分离是实现铁酸锌废渣中有价金属资源回收的关键。提出含大量铁酸锌的锌浸出渣选择性还原焙烧−浸出分离铁和锌的新方法。通过热力学分析确定铁酸锌分解过程中Fe3O4和ZnO产物的优势区域,并发现V(CO)/V(CO+CO2)比是控制铁酸锌还原焙烧产物物相的关键因素,在V(CO)/V(CO+CO2)比在2.68%−36.18%范围内,铁酸锌优先分解生成在Fe3O4和ZnO。通过TG分析,确定铁酸锌还原焙烧的最佳条件为焙烧温度700−750°C,CO体积分数6%,V(CO)/V(CO+CO2)30%。基于上述研究结果,对富含铁酸锌的锌浸渣进行还原焙烧处理,焙烧产物经酸浸后,锌的浸出率达70%,铁的浸出率仅为18.4%,实现锌浸渣中锌和铁的有效分离。%The traditional zinc hydro-metallurgy generates a large amount of zinc ferrite residue rich in valuable metals. The separation of iron is crucial for resource recycling of valuable metals in zinc ferrite residue. A novel selective reduction roasting−leaching process was proposed to separate zinc and iron from zinc leaching residue which contains zinc ferrite. The thermodynamic analysis was employed to determine the predominant range of Fe3O4 and ZnO during reduction roasting process of zinc ferrite. Based on the result of thermodynamic calculation, we found thatV(CO)/V(CO+CO2) ratio is a key factor determining the phase composition in the reduction roasting product of zinc ferrite. In the range ofV(CO)/V(CO+CO2) ratio between 2.68% and 36.18%, zinc ferrite is preferentially decomposed into Fe3O4 and ZnO. Based on thermogravimetric (TG) analysis, the optimal conditions for reduction roasting of zinc ferrite are determined as follows: temperature 700−750 °C, volume fraction of CO 6% and V(CO)/V(CO+CO2) ratio 30%. Based on the above results, zinc leaching residue rich in zinc ferrite was roasted and the roasted product

  19. Nitrate leaching and residual effect in dairy crop rotations with grass-clover leys as influenced by sward age, grazing, cutting and fertilizer regimes

    DEFF Research Database (Denmark)

    Eriksen, Jørgen; Askegaard, Margrethe; Rasmussen, Jim;

    2015-01-01

    Intensive dairy farming, with grass-arable crop rotations is challenged by low N use efficiency that may have adverse environmental consequences. We investigated nitrate leaching and N fertility effects of grass–clover leys for five years in two organic crop rotations with different grassland...... proportions (33 and 67%) and five grassland managements in terms of cutting, grazing, fertilization and combinations thereof. In grass–clover, the combination of fertilization and grazing caused excessive leaching (average 60 kg N ha−1) but leaving out either fertilization or full-time grazing substantially...... and fertilization and lowest without fertilization or cutting-only management and was not influenced by grassland age. The arable part of the mixed crop rotation was nitrate leaky where crop coverage in autumn was insufficient. Nitrate leaching following the crops may roughly be divided into four groups: (1) low...

  20. 大洋锰结核氨浸渣资源化利用研究现状%The State of Art Resource Utilization of Ocean Manganese in Nodules Ammonia Leaching Residue

    Institute of Scientific and Technical Information of China (English)

    赵敏捷; 方建军; 张琳

    2016-01-01

    冶炼大洋锰结核所产生的氨浸渣具有良好的吸附性能、高催化性及优良的电化学特性,具有很高的利用价值。从废水吸附净化、脱硫和材料制备等方面总结了近年来大洋锰结核氨浸渣的应用研究进展。大洋锰结核氨浸渣可有效去除重金属离子净化废水,具有良好的脱硫效果,同时也可广泛应用于离子筛、涂料、改性沥青等材料,具有广阔的资源化利用前景。%Ocean manganese nodules are the important non-ferrous metal resources.Its smelting can produce ammonia leaching residue which has high value for good adsorption ability,including high catalytic and excellent electrochemical characteristics.The paper was introduced from waste water in absorbent and refining function, desulfuration,material preparation and ect.It summarized the state of art research in recent years.The ocean manganese nodules in ammonia leaching residue can effectively remove heavy metal ions to purify the wastewater to have a good desulfurizing effect.It also can be widely used in ionic sieve,coating,the application of modified asphalt and other materials.Ocean manganese in nodules ammonia leaching residue has a broad resource utilization prospect,and it will be of a higher industrial utilization value.

  1. 湿法生产锑白渣中硫磺的回收工艺%Reclaiming technology of sulphur from leaching residue of antimony white with hydrometallurgical process

    Institute of Scientific and Technical Information of China (English)

    王文侠

    2012-01-01

    A sulphur reclaiming method from leaching residue of antimony white with hydrometallurgical process was introduced. Ammonia sulfide solution was selected as extracted liquor,and sulphur in leaching residue could form polysulfide ions, which will dissolve in the solution.The filtrate was separated out through suction filtration and the thermal decomposition was carried out.The produced gas was led out and absorbed, which can be used circularly.Finally, sulphur product could be prepared through thermal decomposition of filtrate.The best extraction conditions included the ratio of solid to liquid of 1:20, leaching time of 2 h,and leaching temperature of 20 t.The process had many advantages,such as equipment,technology, and sulphur extracting operation were very simple,the extract liquid could be returned for recycling,the cost was lower, the quality of the sulphur products was good,and the total sulphur recovery could reach over 99%.At the same time,the waste residue of antimony prodcution was recycled and utilized comprehensively, so that the pollution of the environment and the pile-up of waste residue could be reduced.%介绍了一种从湿法生产锑白渣中回收硫磺的方法.以硫化铵溶液作为提取液浸取矿渣,矿渣中的硫可生成多硫离子而溶解转入溶液中,抽滤分离出滤液,将产生的气体导出并吸收,吸收后可返回循环使用;滤液热分解后可得到硫磺产品.最佳提取条件:固液比为1:20、浸取温度为20℃、浸取时间为2 h.该工艺设备及提硫操作简单,硫化铵可循环利用,成本较低,硫磺产品的质量较好,硫的总回收率可达99%以上.同时利用了浸锑废渣,实现资源 综合回收利用,又减少环境污染和废渣的堆积量.

  2. 难处理铅锌矿酸浸渣回收硫酸铅的工艺研究%Study on recovery lead sulfate from complex acid leaching residue of lead-zinc mine

    Institute of Scientific and Technical Information of China (English)

    张传宝; 颜文斌; 徐辉; 高峰; 华骏

    2012-01-01

    The extraction process using sodium chloride and suliuric acid mixed solution, leaching lead from complex acid leaching residue of lead-zinc mine and preparing the lead sulfate by dilute leaching so lution. The influences of sodium chloride concentration,the liquid-solid ratio,time,temperature,acid concentration on lead leaching rate and diluted times,time on the lead sulfate precipitation was discussed. The results showed that the lead leaching rate of 82. 1% . when sodium chloride concentration of 330 g/L, sulfuric acid concentration of 1 mol/L,the liquid-solid ratio of 7: 1 at 95℃ for 1. 5 h, the purity of 99.1% products. The leaching solution in diluted times of 2.5 for standing time 7 h,lead sulfate precipitation rate was 93%. The lead recovery rate was 76% , it was improved by more than 30% compared with the traditional method.%采用氯化钠-硫酸混合溶液对铅锌矿难处理酸浸渣进行浸出,对浸出液稀释,制备硫酸铅,考察了氯化钠浓度、液固比、时间、温度和硫酸浓度等因素对酸浸渣的浸出影响和考察稀释倍数、时间等因素对沉淀硫酸铅的影响.结果表明,在氯化钠浓度为330 g/L,液固比为7:1,时间为1.5h,温度95℃,硫酸浓度为1mol/L的条件下,铅的浸出率为82.1%;在浸出液稀释倍数为2.5,静置时间7h的条件下,硫酸铅的沉淀率为93%,产品纯度为99.1%.铅的回收率为76%,比传统方法提高30%以上.

  3. Study on process of recovering lead from acid leaching residue by precipitation transformation method%沉淀转化法综合回收酸浸渣中铅的工艺研究

    Institute of Scientific and Technical Information of China (English)

    张福元; 俎小凤; 彭国敏

    2013-01-01

    Comprehensive recovery of low-grade lead in the acid leaching residue from cyanidation process for golden leaching was made through precipitation transformation method.The recovery process was introduced.Influences of factors, such as mass ratio of liquid to solid (L/S), amount of ammonium bicarbonate, and reaction time on converting rate of lead in the reaction process of ammonium bicarbonate and acid leaching residue were also studied through orthogonal tests.The optimum conditions were as follows:mass ratio of L/S was 2.0,amount of ammonium bicarbonate was 30 g,and reaction time was 2.0 h. The transformation ratio of lead reached 97% under those conditions.%通过沉淀转化法对氰化提金工艺酸浸渣中低品位铅进行了综合回收.介绍了回收工艺流程,通过正交实验考察了酸浸渣采用碳酸氢铵转化过程中液固比、碳酸氢铵用量、转化时间等因素对铅转化率的影响,确定了转化反应的最佳条件为:转化液固质量比为2.0、碳酸氢铵用量为30 g、转化时间为2.0 h.在最佳条件下反应,铅转化率可达97%.

  4. Test and Research on Comprehensive Recovery of Indium, Germanium, Lead and Silver from Residue of Zinc Dross Leaching%从锌渣浸渣中综合回收铟锗铅银的试验研究

    Institute of Scientific and Technical Information of China (English)

    郑顺德; 陈世民; 林兴铭; 李裕后; 李俊红

    2001-01-01

    本文介绍用新工艺从锌渣浸渣中综合回收铟、锗、铅、银的试验概况。试验结果表明:从锌渣浸渣到得到粗铅、锗富集物、粗铟,铅银的直收率均大于85%,锗的回收率大于82%,铟的直收率大于82%。该工艺优于以前采用的任何工艺。%The results of test on comprehensive recovery of indium, germanium, lead and silver from residue of zinc dross leaching using new process show that it is possible to produce crude lead, enriched germanium and crud indium from residue of zinc dross leaching, and the direct recovery of lead and silver is higher than 85%; recovery of germanium, higher than 82% and direct recovery of indium, higher than 82%. This process is superior over any other processes adopted previously.

  5. Mercury Levels In Fly Ash And Apc Residue From Municipal Solid Waste Incineration Before And After Electrodialytic Remediation

    DEFF Research Database (Denmark)

    Dias-Ferreira, Celia; Kirkelund, Gunvor Marie; Jensen, Pernille Erland

    2016-01-01

    Fly ash (FA) and Air Pollution Control (APC) residues collected from three municipal solid waste incinerators (MSWI) in Denmark and Greenland were treated by electrodialytic remediation at pilot scale for 8 to 10 h. The original residues and the treated material were analysed for mercury (Hg...... carbon. Two distinct behaviours were observed for mercury as a result of the electrodialytic treatment. This element became enriched in the MSWI residues from the semi-dry system with activated carbon, whereas it decreased in ESP’s and cyclone’s FA. This work presents for the first time information about...

  6. Thermally induced transformations of iron oxide stabilised APC residues from waste incineration

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Koch, C.B.

    2001-01-01

    Air pollution control (APC) facilities at waste incinerator plants produce large quantities of solid residues rich in salts and heavy metals. Heavy metals are readily released to water from the residues and it has, therefore, been found suitable to apply a rapid co-precipitation/adsorption process...... elements associated with the ferrihydrite are Si and Ca. Following heating to 600 degreesC the oxide is still characterized as an amorphous Fe oxide, and it is probable that Si associated with the ferrihydrite is decisive in preventing crystallization. After the 900 degreesC treatment a transformation...

  7. Long-term pollution by chlordecone of tropical volcanic soils in the French West Indies: A simple leaching model accounts for current residue

    Energy Technology Data Exchange (ETDEWEB)

    Cabidoche, Y.-M., E-mail: cabidoch@antilles.inra.f [INRA, UR 135 Agropedoclimatique de la Zone Caraibe, Environment and Agronomy, Domaine Duclos, 97170 Petit-Bourg, Guadeloupe (France); Achard, R., E-mail: achard@cirad.f [CIRAD, UPR Systemes Bananes et Ananas (Martinique), 97285 Le Lamentin (France); Cattan, P., E-mail: cattan@cirad.f [CIRAD, UPR Systemes Bananes et Ananas (Guadeloupe), 97130 Capesterre-Belle-Eau (France); Clermont-Dauphin, C., E-mail: clermont@ird.f [INRA, UR 135 Agropedoclimatique de la Zone Caraibe, Environment and Agronomy, Domaine Duclos, 97170 Petit-Bourg, Guadeloupe (France); Massat, F., E-mail: fmassat@ladrome.f [Laboratoire Departemental d' Analyses de la Drome, LDA26, 26000 Valence (France); Sansoulet, J., E-mail: Julie.Sansoulet@cirad.f [INRA, UR 135 Agropedoclimatique de la Zone Caraibe, Environment and Agronomy, Domaine Duclos, 97170 Petit-Bourg, Guadeloupe (France)

    2009-05-15

    Chlordecone was applied between 1972 and 1993 in banana fields of the French West Indies. This resulted in long-term pollution of soils and contamination of waters, aquatic biota, and crops. To assess pollution level and duration according to soil type, WISORCH, a leaching model based on first-order desorption kinetics, was developed and run. Its input parameters are soil organic carbon content (SOC) and SOC/water partitioning coefficient (K{sub oc}). It accounts for current chlordecone soil contents and drainage water concentrations. The model was valid for andosol, which indicates that neither physico-chemical nor microbial degradation occurred. Dilution by previous deep tillages makes soil scrapping unrealistic. Lixiviation appeared the main way to reduce pollution. Besides the SOC and rainfall increases, K{sub oc} increased from nitisol to ferralsol and then andosol while lixiviation efficiency decreased. Consequently, pollution is bound to last for several decades for nitisol, centuries for ferralsol, and half a millennium for andosol. - Soil and water contamination by chlordecone will persist for several centuries in the French West Indies, because the only decontamination is through leaching by drainage water.

  8. Minimization of methabenzthiazuron residues in leaching water using amended soils and photocatalytic treatment with TiO2 and ZnO.

    Science.gov (United States)

    Fenoll, José; Flores, Pilar; Hellín, Pilar; Hernández, Joaquín; Navarro, Simon

    2014-04-01

    In the present work, potential groundwater pollution by methabenzthiazuron (MTBU) and the effect of three different amendments (composted sheep manure, composted pine bark and spent coffee grounds) on its mobility were investigated under laboratory conditions. The efficiency of ZnO and TiO2 suspensions in the photocatalytic degradation of MTBU in leaching water was also investigated. The relative and cumulative breakthrough curves were obtained from disturbed soil columns. The presence and/or addition of organic matter drastically reduced the movement of the herbicide. On other hand, photocatalytic experiments showed that the addition of ZnO and TiO2 strongly enhances the degradation rate of this herbicide compared with the results of photolytic experiments under artificial light. ZnO appeared to be more effective in MTBU oxidation than TiO2. The results obtained point to the interest of using organic wastes and heterogeneous photocatalysis for reducing the pollution of groundwater by pesticide drainage.

  9. Minimization of methabenzthiazuron residues in leaching water using amended soils and photocatalytic treatment with TiO2 and ZnO.

    Science.gov (United States)

    Fenoll, José; Flores, Pilar; Hellín, Pilar; Hernández, Joaquín; Navarro, Simon

    2014-04-01

    In the present work, potential groundwater pollution by methabenzthiazuron (MTBU) and the effect of three different amendments (composted sheep manure, composted pine bark and spent coffee grounds) on its mobility were investigated under laboratory conditions. The efficiency of ZnO and TiO2 suspensions in the photocatalytic degradation of MTBU in leaching water was also investigated. The relative and cumulative breakthrough curves were obtained from disturbed soil columns. The presence and/or addition of organic matter drastically reduced the movement of the herbicide. On other hand, photocatalytic experiments showed that the addition of ZnO and TiO2 strongly enhances the degradation rate of this herbicide compared with the results of photolytic experiments under artificial light. ZnO appeared to be more effective in MTBU oxidation than TiO2. The results obtained point to the interest of using organic wastes and heterogeneous photocatalysis for reducing the pollution of groundwater by pesticide drainage. PMID:25079405

  10. 基于剩余能量和睡眠控制的改进LEACH算法%Improvement of LEACH algorithm based on residual energy and node sleep schedule

    Institute of Scientific and Technical Information of China (English)

    韩媛萍

    2012-01-01

    无线传感器网络(WSN)路由协议研究的一个重要的目标是如何在有限的能源下降低整个网络的能耗,提高网络的生存时间.以分簇路由协议LEACH为研究基础,提出了一种改进算法.该算法改进了簇首选择规则,引入协调件协议算法,通过在成簇阶段降低剩余能量低的节点被选择成为簇首的概率,在稳定运行阶段使簇首节点尽可能多的保持睡眠状态,从而降低了网络能耗.仿真结果表明,与原LEACH算法相比,改进的算法能够明显地延长网络生存时间.%The most important goal for routing protocol research on wireless sensor networks is to reduce the energy consumption and prolong the lifetime of the network. Based on the cluster-based routing protocol LEACH, a new improved algorithm is put forward in this paper. This algorithm improved the cluster head selection rules and combined MD protocol algorithm. It can effectively reduce the probability of nodes with lower residual energy chosen to be the cluster head and make the cluster head as much as possible to maintain the sleep state. The results of simulation show that the improved protocol prolong the network lifetime more effectively in comparison with the original LEACH protocol.

  11. Design Optimization and Development in Air Pollution Control Device

    Directory of Open Access Journals (Sweden)

    Rahul Ligade

    2014-07-01

    Full Text Available Electrostatic Precipitators (ESP is the device used to remove the dust particles from the processed gases coming out of boilers in cement industries, and iron core industries. There are many governing factors that affect the efficiency from that one major reason is to fully filled hopper. When hopper fills 70 % of its full limit the precipitation process stopped of that particular hopper. For remedy dust removal efficiency is increased by hopper vibrator at the time of emptying bagasse ash from the hopper. The maximum displacement is getting by using different hopper wall thicknesses, stiffener spacing as well as different configuration vibrators. Due to minimum time to complete project there are many difficulties to test at every stage to improve the design and this results in increased project cost. For this situation there is one simple way to improve the design of equipment’s through simulation in ANSYS and validation by actual physical measurements. This project presents FEA approach for modeling and analysis the hopper of electrostatic precipitator using Static, Modal and Harmonic analysis. Actual model testing is done for the validation of results. The results coming out from the FEA analysis and testing are discussed.

  12. Asbestos: The Need for and Feasibility of Air Pollution Controls.

    Science.gov (United States)

    National Academy of Sciences - National Research Council, Washington, DC. Div. of Medical Sciences.

    The monograph presents a brief summary of the problems associated with airborne asbestos. It discusses the evidence regarding the pathogenicity of asbestos in man and animals, considers the evidence of human non-occupational exposure to asbestos, evaluates the evidence regarding health risks associated with various degrees and types of exposure,…

  13. The Efficacy of Air Pollution Control Efforts: Evidence from AURA

    Science.gov (United States)

    Dickerson, Russell R.; Canty, Tim; Duncan, Bryan N.; Hao, He; Krotkov, Nickolay A.; Salawitch, Ross J.; Stehr, Jeffrey W.; Vinnikov, Konstatin

    2014-01-01

    Observations of NO2, SO2, and H2CO from OMI on AURA provide an excellent record of pollutant concentrations for the past decade. Abatement strategies to control criteria pollutants including ozone and fine particulate matter (PM2.5) have met with varying degrees of success. Sulfur controls had a profound impact on local SO2 concentrations and a measurable impact on PM2.5. Although substantial effort has gone into VOC control, ozone in the eastern US has responded dramatically to NOx emissions controls.

  14. Measures related to traffic planning for air pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Baumueller, J.; Reuter, U. [Office of Environmental Protection, Stuttgart (Germany). Dept. for Climatology

    1995-12-31

    The immense increase of motor traffic, in the future reinforced by the European market and the opening of boarders to the east countries, requires new efforts in traffic policy. In the city agglomerations the motor traffic is nearly collapsing. The increase of motor traffic is the reason for a considerable degradation of environment, especially by noise and air pollution. For the region of Stuttgart the problems and possibilities of counter-measures are discussed. (author)

  15. LEAD AND ZINC LEACHING IN SOIL TREATED WITH IRON SMELTING RESIDUES LIXIVIAÇÃO DE CHUMBO E ZINCO EM SOLO TRATADO COM RESÍDUOS DE SIDERURGIA

    Directory of Open Access Journals (Sweden)

    Leônidas Paixão Passos

    2010-10-01

    Full Text Available

    In order to evaluate the dynamics of Zn and Pb in the soil, a greenhouse experiment was set up in pots filled with soil samples (Typic Hapludox treated with increasing doses of iron smelting residues. It was set under a completely randomized design, in a 3×5 factorial scheme, with three replications, combining three iron smelting residues (mill scale, filter press mud, and phosphate mud, with five doses for each residue (0 t ha-1, 1 t ha-1, 2 t ha-1, 4 t ha-1, and 8 t ha-1. Elephant grass was cultivated during 120 days, followed by common beans, for 75 days. In that period, contents of Zn and Pb were determined in the leachate. No Pb was found in the leachate, but Zn proved to be quite mobile in this soil. In soils treated with mill scale and filter press mud, no risk of groundwater contamination was observed, however, the 8 t ha-1 phosphate mud rate increased Zn contents in the leachate above the maximum allowed by environmental regulations. This fact limits the use of such residue for agricultural purposes. The other two residues should be evaluated in field-scale tests aiming their agricultural use.

    KEY-WORDS: Industrial residue; heavy metal; mill scale; filter press mud; phosphate mud.

  16. Main means for reducing the production costs in process of leaching uranium

    International Nuclear Information System (INIS)

    The production costs in process of leaching uranium have been reduced by controlling mixture ratio of crudes, milling particle size, liquid/solid mass ratio of leaching pulp, potential and residue acidity, and improving power equipment

  17. Determination of Lead Content in Lead Residue and Water Leached Residue with EDTA Volumetric Method%EDTA容量法测定铅渣水浸渣中铅含量

    Institute of Scientific and Technical Information of China (English)

    田海燕; 刘云

    2011-01-01

    提出了铅渣试样中测定铅含量时消除铋干扰的掩蔽方法.该方法利用巯基乙酸掩蔽铋,使铅的测定结果稳定可靠,满足了生产需要.%The screening method for removing bismuth interference at the time of determination of lead content in lead residue sample. In this method, thioglycolic acid is adopted to screen bismuth, so that the determination result of lead is reliable and stable. It can meet the requirements of production.

  18. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    OpenAIRE

    Allegrini, Elisa; Boldrin, Alessio; Jansson, S.; Lundtorp, K.; Astrup, Thomas Fruergaard

    2014-01-01

    The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along t...

  19. 碳还原锌浸出渣炼铁过程的热力学分析%Thermodynamic analysis on iron-making process of zinc leaching residue by carbon reduction

    Institute of Scientific and Technical Information of China (English)

    刘洋; 谭军; 刘常青; 尹周澜; 陈启元; 张平民; 廖舟

    2015-01-01

    对锌浸出渣熔池熔炼碳还原炼铁反应过程进行了热力学分析。结果表明:ZnFe2O4和 KFe3(SO4)2(OH)6受热分解的含铁产物是Fe2O3,ZnFe2O4在300~1800 K温度范围内不能自发分解,KFe3(SO4)2(OH)6在652.25K即可分解;高pCO/pCO2、低温(但要高于炉渣熔融的温度)有利于熔体中的Fe2O3还原生成液态铁;含硫物相低温分解后的产物有金属硫酸盐 K2SO4和 CaSO4,两者热分解脱硫的有利条件均是高温及低硫分压、低氧分压(但氧分压要高于硫酸盐分解生成硫化物的限值),CaSO4热分解脱硫比K2SO4易于进行。锌浸出渣中碱性氧化物CaO的存在,一方面可以降低Zn2SiO4碳热还原的起始反应温度,另一方面可以提高炉渣碱度及炉渣中CaO的活度,降低硫在铁液与炉渣中的分配平衡常数。%Iron-making of zinc leaching residue was obtained by carbon reduction in bath smelting, and the thermodynamic process was analyzed. The results show that Fe2O3is the pyrolysis product of ZnFe2O4 and KFe3(SO4)2(OH)6. ZnFe2O4 can not decompose in the temperature range of 300−1800 K, but KFe3(SO4)2(OH)6 decomposes at 652.25K. HigherpCO/pCO2and lower temperature that should be higher than the slag melting temperature, are favor able to the reduction of Fe2O3. The metal sulfates of K2SO4and CaSO4 are decomposing products of sulfur-contained phases at low temperature, and the favorable desulfurization conditions of K2SO4and CaSO4 are high temperature, low sulfur-partial pressure and low oxygen-partial pressure that must be higher than the limit of sulfates converting into sulfides. The desulfurization of CaSO4 is easier than that of K2SO4. CaO in zinc leaching residue reduces the initial reaction temperature of Zn2SiO4reduction, improves slag basicity and activity of CaO in slag and decreases the sulfur distribution ratio between liquid iron and molten slag.

  20. Lixiviação de nutrientes em solo cultivado com aplicação de água residuária de suinocultura Leaching of nutrients in cultivated soils under application of residual water of pig farming

    Directory of Open Access Journals (Sweden)

    Cacea F Maggi

    2011-02-01

    Full Text Available Objetivou-se neste trabalho avaliar os impactos do percolado em lisímetros de drenagem com a aplicação de diferentes taxas de água residuária de suinocultura (ARS durante o ciclo da cultura da soja. Conduziu-se o experimento no Núcleo Experimental de Engenharia Agrícola da UNIOESTE, em solo foi classificado como Latossolo Vermelho distroférrico. A área dispunha 24 lisímetros de drenagem, na qual se semeou a cultura da soja, cultivar CD 214. Porém, sete dias antes da semeadura, em única aplicação foram aplicadas ao solo quatro taxas de ARS (0, 100, 200 e 300 m³ ha-1 sete dias antes da semeadura, em uma única aplicação, combinadas com duas adubações na semeadura (com adição e sem adição da adubação recomendada na semeadura e três repetições por tratamento. Foram realizadas três coletas do percolado em cada parcela experimental, a primeira aos 40 dias após a semeadura (DAS, a segunda aos 72 DAS e a terceira no final do ciclo da cultura (117 DAS. Avalioram-se pH, cálcio, magnésio, potássio, fósforo e nitrogênio total. Com base nos resultados observou-se que os valores de pH e Mg no percolado não sofreram influência pela aplicação de ARS e adubação. As concentrações de K+, P e Ca+2 no percolado foram maiores para taxas mais elevadas de ARS.This work aimed to evaluate the impacts on leachate from drainage lysimeters receiving application of different rates of pig farming residual water (PRW during soybean crop cycle. The experiment was conducted at the Agricultural Engineering Experimental field of UNIOESTE. The soil was classified as Rhodic Ferralsols. There were twenty-four drainage lysimeters where soybean cultivar CD 214 was sown. Four PRW rates (0; 100; 200 and 300 m³ ha-1 were applied to the soil seven days before sowing in a single application combined with two fertilizations (with and without recommended dose during sowing, and three repetitions per treatment. Three leachate collections were carried

  1. Leaching from municipal solid waste incineration residues

    DEFF Research Database (Denmark)

    Hyks, Jiri

    2008-01-01

    I dette studie er udvaskning af farlige stoffer fra restprodukter fra affaldsforbrænding blevet undersøgt ved at kombinere udvaskningstests i laboratoriet med geokemisk modellering. Der blev lagt særlig vægt på at undersøge anvendelsen af laboratoriedata i forhold til efterfølgende modellering af...

  2. Immobilized waste leaching

    International Nuclear Information System (INIS)

    The main mechanism by which the immobilized radioactive materials can return to biosphere is the leaching due to the intrusion of water into the repositories. Some mathematical models and experiments utilized to evaluate the leaching rates in different immobilization matrices are described. (author)

  3. In situ leaching of uranium

    International Nuclear Information System (INIS)

    A process is described for the in-situ leaching of uranium-containing ores employing an acidic leach liquor containing peroxymonosulphuric acid. Preferably, additionally, sulphuric acid is present in the leach liquor. (author)

  4. Alkaline leaching of metal melting industry wastes dseparation of zinc and lead in the leach solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this work, a thorough examinations on the extractability of zinc and lead present in the steelmaking dusts using alkaline leaching process and the effectiveness of the zinc and lead separation in the resultant leaching solutions using sulfide precipitation method were made. It was found that only about 53% of zinc and over 70% of the lead could be leached out of the dusts, while the other 47% of zinc and 306 of lead were left in the leaching residues. The zinc and lead in the resultant leaching solution can be effectively and selectively separated. When the weight ratio of sodium sulfide (M. W. = 222-240) to Pb was kept at 1.8, the lead in the solution could be precipitated out quantitatively while all the zinc was remained in the solution. The zinc left in the solution can be further recovered by the addition of extra sodium sulfide with a weight ratio of sodium sulfide to the zinc over 2.6. The resultant filtrate can be recycled to the leaching of dust in the next leaching process.

  5. 北京奥运大气污染控制措施对大气细颗粒物金属组分及其细胞毒性的影响%Influence of Air Pollution Control during 2008 Beijing Olympic Games on Metal Components and Cytotoxicity of PM2.5

    Institute of Scientific and Technical Information of China (English)

    魏红英; 邓芙蓉; 郭新彪

    2011-01-01

    Objective To study the influece of the pollution control measures for the 2008 Beijing Olympic Games on the metal components and the cytotoxicity of fine particulate matter (PM2.5). Methods PM2.5 was collected before and during Beijing Olympic Games in 2008. The metal elements of PM2.5 were analyzed. The AS49 cell was exposed to two kinds of PM2.5 for 24 h at different concentrations. After 24 h of exposure, the cell membrane permeability, the activity of mitochondrial succinate dehydrogenase (SDH) and the leakage of acid phosphatase (ACP) were detected. Results The contents of metal elements of PM2.5 collected during Beijing Olympic Games were lower than those of which collected before Beijing Olympic Games. Above 5 μg/ml, both kinds of PM2.5 could significantly induce the suppression of SDH activity and the increase in ACP leakage, while the increase in cell membrane permeability was observed at the higher concentration. Compared with PM2.5 collected before Beijing Olympic Games, the impact of PM2.5 collected during Beijing Olympic Games on cell membrane induced significantly decrease in 25 and 125 μg/ml groups. Conclusion Two kinds of PM2.5 show significant cytotoxicity on A549 cell. The reduction of cell membrane toxicity of PM2.5 collected during Beijing Olympic games may be associated with the reduction of the metal components resulted from the air pollution control measures for the 2008 Beijing Olympic Games.%目的 探讨2008北京奥运相关大气污染控制措施对大气细颗粒物(PM2.5)金属组分及其细胞毒性的影响.方法于2008年采集奥运前与奥运期间PM2.5,以电感耦合等离子体质谱仪和发射光谱仪测定PM2.5中金属元素含量.以不同浓度的两种PM2.5处理人肺腺癌A549细胞24h,观察PM2.5对细胞膜通透性、线粒体琥珀酸脱氢酶(SDH)活力及溶酶体酸性磷酸酶(ACP)漏出的影响.结果奥运期间PM2.5元素含量大多低于奥运前PM2.5.与对照组相比,奥运前与奥运期间PM2

  6. Uranium in situ leaching

    International Nuclear Information System (INIS)

    Despite the depressed situation that has affected the uranium industry during the past years, the second Technical Committee Meeting on Uranium In Situ Leaching, organized by the International Atomic Energy Agency and held in Vienna from 5 to 8 October 1992, has attracted a relatively large number of participants. A notable development since the first meeting was that the majority of the contributions came from the actual operators of in situ leaching uranium production. At the present meeting, presentations on operations in the USA were balanced by those of the eastern European and Asian countries. Contributions from Bulgaria, China, Czechoslovakia, Germany (from the operation in the former German Democratic Republic), the Russian Federation and Uzbekistan represent new information not commonly available. In situ leach mining is defined in one of the paper presented as a ''mining method where the ore mineral is preferentially leached from the host rock in place, or in situ, by the use of leach solutions, and the mineral value is recovered. Refs, figs and tabs

  7. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching.

    Science.gov (United States)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

    2016-08-01

    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 LiMn2O4, LiCoxMnyNizO2, Al2O3 and C while the leach residue is composed of LiNixMnyCozO2, LiMn2O4, Al2O3, MnCO3 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. PMID:27060219

  8. Extraction of toxic and valuable metals from wastewater sludge and ash arising from RECICLAGUA, a treatment plant for residual waters applying the leaching technique; Extraccion de metales toxicos y valiosos de los desechos de lodos y cenizas provenientes de la planta tratadora de aguas residuales RECICLAGUA aplicando la tecnica de lixiviado

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero D, J.J

    2004-07-01

    Presently work, the technique is applied of having leached using coupled thermostatted columns, the X-ray diffraction for the identification of the atomic and molecular structure of the metals toxic that are present in the residual muds of a treatment plant of water located in the municipality of the Estado de Mexico, RECICLAGUA, likewise the techniques is used of Inductively Coupled Plasma Mass Spectroscopy and X-ray fluorescence analysis for the qualitative analysis. We took samples of residual sludge and incinerated ash of a treatment plant waste water from the industrial corridor Toluca-Lerma RECICLAGUA, located in Lerma, Estado de Mexico. For this study 100 g. of residual of sludge mixed with a solution to 10% of mineral acid or sodium hydroxide according to the case, to adjust the one p H at 2, 5, 7 and 10, bisulfite was added, of 0.3-1.5 g of dodecyl sulfate of sodium and 3.93 g of DTPA (triple V). Diethylene triamine penta acetate. These sludges and ashes were extracted from toxic and valuable metals by means of the leaching technique using coupled thermostated columns that which were designed by Dr. Jaime Vite Torres, it is necessary to make mention that so much the process as the apparatus with those that one worked was patented by him same. With the extraction of these metals, benefits are obtained, mainly of economic type, achieving the decrease of the volume of those wastes that have been generated; as well as the so much use of those residuals, once the metals have been eliminated, as of those residuals, once the metals have been eliminated, as of those liquors, the heavy metals were extracted. It was carried out a quantitative analysis using Icp mass spectroscopy, this way to be able to know the one content of the present metals in the samples before and after of leaching them, these results reported a great quantity of elements. Another of the techniques employees was the analysis by X-ray diffraction that provides an elementary content of the

  9. In-situ uranium leaching

    International Nuclear Information System (INIS)

    This invention provides a method for improving the recovery of mineral values from ore bodies subjected to in-situ leaching by controlling the flow behaviour of the leaching solution. In particular, the invention relates to an in-situ leaching operation employing a foam for mobility control of the leaching solution. A foam bank is either introduced into the ore bed or developed in-situ in the ore bed. The foam then becomes a diverting agent forcing the leaching fluid through the previously non-contacted regions of the deposit

  10. Lead sulphate leaching by sodium chloride solution

    Directory of Open Access Journals (Sweden)

    Conić Vesna T.

    2013-01-01

    Full Text Available Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II sulfate (PbSO4 sludge. To determine the leaching parameters of PbSO4 with NaCl in the bioleaching residue, lead sulphate solution was synthetically prepared. The effect of process parameters, namely NaCl concentration, solid:liquid phase ratio, processing time, temperature and Cl ions was examined. It was found that 100% Pb by leaching can be achieved with NaCl concentration of 250 g/dm3, time 20 min, temperature 353 K and solid:liquid phase ratio =1:20.

  11. Gold leaching with elemental sulfur in alkaline solutions under oxygen pressure

    Institute of Scientific and Technical Information of China (English)

    方兆珩; 石伟

    2003-01-01

    A gold leaching process by using oxidation products of elemental sulfur in alkaline solutions was pro-posed and investigated. A gold concentrate and a residue from an arsenic refractory gold concentrate by acidic oxida-tion leaching were tested. The residue contains 16.3% elemental sulfur and no more elemental sulfur was added intests. For the concentrate elemental sulfur was added before leaching tests. The leaching ratio of gold depends main-ly on the initial equivalent ratio of elemental sulfur to hydroxyl ions, the consumption of oxygen and the reactiontemperature in the process. Analysis of the experimental results shows that thiosulfate is the majority complexingreagent for gold in the process. Over 90% gold was leached from the residue and 82%-87% from the concentrate byusing this process.

  12. Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

    Science.gov (United States)

    Zhang, Biao; Li, Mi; Zhang, Xiaowen; Huang, Jing

    2016-07-01

    Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)-0.14903(S/L)-1.80435( R o)0.20023 e -1670.93/T t ( t ≥ 5) to 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)0.01382(S/L)-1.83275( R o)0.25763 e -1654.59/T t ( t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

  13. Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

    Science.gov (United States)

    Zhang, Biao; Li, Mi; Zhang, Xiaowen; Huang, Jing

    2016-05-01

    Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)-0.14903(S/L)-1.80435(R o)0.20023 e -1670.93/T t (t ≥ 5) to 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)0.01382(S/L)-1.83275(R o)0.25763 e -1654.59/T t (t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

  14. Leaching of metals from copper smelter flue dust (Mufulira, Zambian Copperbelt)

    DEFF Research Database (Denmark)

    Vítková, Martina; Ettler, Vojtěch; Hyks, Jiri;

    2011-01-01

    ) and delafossite (CuFeO2) represented the principal phases of the studied dust. In contact with water, chalcanthite was dissolved and hydrated Cu sulphates precipitated at pH4–7. Gypsum (CaSO4·2H2O) and secondary Fe or Al phases were observed in the leached residues. Serious environmental impact due to leaching...

  15. Enhancement of accelerated carbonation of alkaline waste residues by ultrasound.

    Science.gov (United States)

    Araizi, Paris K; Hills, Colin D; Maries, Alan; Gunning, Peter J; Wray, David S

    2016-04-01

    The continuous growth of anthropogenic CO2 emissions into the atmosphere and the disposal of hazardous wastes into landfills present serious economic and environmental issues. Reaction of CO2 with alkaline residues or cementitius materials, known as accelerated carbonation, occurs rapidly under ambient temperature and pressure and is a proven and effective process of sequestering the gas. Moreover, further improvement of the reaction efficiency would increase the amount of CO2 that could be permanently sequestered into solid products. This paper examines the potential of enhancing the accelerated carbonation of air pollution control residues, cement bypass dust and ladle slag by applying ultrasound at various water-to-solid (w/s) ratios. Experimental results showed that application of ultrasound increased the CO2 uptake by up to four times at high w/s ratios, whereas the reactivity at low water content showed little change compared with controls. Upon sonication, the particle size of the waste residues decreased and the amount of calcite precipitates increased. Finally, the sonicated particles exhibited a rounded morphology when observed by scanning electron microscopy. PMID:26905698

  16. 一种LEACH协议的改进算法LEACH_EH%An improved algorithm of LEACH protocol LEACH-EH

    Institute of Scientific and Technical Information of China (English)

    徐鹏

    2014-01-01

    根据 LEACH 协议的特点和局限性对其进行了改进,提出了一种 LEACH_EH ( LEACH EAHANCE )算法。它使用 K_MEANS 算法对簇进行一次性分簇,之后结合节点到簇内质心距离与节点自身剩余能量选举出簇头。它将簇形成的顺序由先簇头后成簇变为先成簇后簇头,形成一次分簇多次选举簇头的模式。通过 MATLAB 进行仿真,实验结果表明,改进后的算法比原来的协议在节点能量均衡方面有了较大的提升,延长了网络生存周期。%This paper propose a LEACH_EH algorithm based on the characteristics and limitations of the LEACH protocol.It uses the K_MEANS algorithm to cluster only once, and then elects the cluster heads by considersing the distance from node to cluster center and the node′s residual energy. It makes the order from electing cluster first and clustering second to clustering first and electing cluster second. It forms the formation of clustering only once and electing cluster multi-times. The MATLAB simulation shows that comparing with LEACH, the LEACH_ED algorithm has a great improvement in the energy balance of the node,and prolong the network life cycle abviously.

  17. Recycling utilization of iron in heap leaching solution

    International Nuclear Information System (INIS)

    The feasibility tests have been conducted, which involve that Fe2+ containing absorption effluent solution was oxidized by pyrolusite, and neutralizing-precipitation iron from eluent. Both the oxidized solution and neutralizing-precipitation iron residue were recycled to leaching system as oxidizer. The results showed that the oxidation-reduction potential in solution raised from 370 mV to 450 mV, the iron residue could provide high performance for filtrating and subsiding

  18. Lead sulphate leaching by sodium chloride solution

    OpenAIRE

    Conić Vesna T.; Pešovski Branka D.; Cvetkovski Vladimir B.; Stanojević-Šimšić Zdenka S.; Dragulović Suzana S.; Simonović Danijela B.; Dimitrijević Silvana B.

    2013-01-01

    Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II) sulfate (PbSO4) sludge. To determine the leaching parameters of PbSO4 with NaCl in the bioleaching residue, lead sulphate solution was synthetically prepared. The effect of process parameters, namely NaCl concentration, solid:liquid phase ratio, processing time, temperature and Cl ions was examined. It wa...

  19. Concentrating Ge in zinc hydrometallurgical process with hot acid leaching-halotrichite method

    Institute of Scientific and Technical Information of China (English)

    何静; 唐谟堂; 鲁君乐; 刘中清; 杨声海; 姚维义

    2003-01-01

    In recovering Ge and Ag from the calcine and fume dusts mixture of Huidong Lead-zinc Mine, the flow sheet of hot acid leaching-halotrichite method mainly consists of neutral leaching, low-acid leaching, high acid leaching and jarosite precipitation. In the ten circulation periods, the technology flow sheet was carried out smoothly.The loss of Ge in halotrichite residue is less than 5.0%, when iron is precipitated by using ferric potassium alum instead of common Na or ammonium alum and the conditions are controlled at temperature about 95 ℃ for more than 3 h, pH values below 1.5. Ge and Ag are concentrated in the high acid leached residue, and their contents are 0. 032% and 0. 162%, respectively, and the total recovery and direct recovery of zinc are 98.94% and 96.15%, respectively.

  20. 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...

  1. Flow analysis of heavy metals in a pilot-scale incinerator for residues from waste electrical and electronic equipment dismantling

    Energy Technology Data Exchange (ETDEWEB)

    Long, Yu-Yang; Feng, Yi-Jian; Cai, Si-Shi; Ding, Wei-Xu; Shen, Dong-Sheng, E-mail: shends@zju.edu.cn

    2013-10-15

    Highlights: • Cu, Zn, Pb, and Ni are enriched in bottom ash from WEEE dismantling residues. • The heavy metal residual fraction restricts transfer in the incinerator. • Pre-treatment to remove heavy metals from WEEE residues would reduce emissions. -- Abstract: The large amount of residues generated from dismantling waste electrical and electronic equipment (WEEE) results in a considerable environmental burden. We used material flow analysis to investigate heavy metal behavior in an incineration plant in China used exclusively to incinerate residues from WEEE dismantling. The heavy metals tested were enriched in the bottom and fly ashes after incineration. However, the contents of heavy metals in the bottom ash, fly ash and exhaust gas do not have a significant correlation with that of the input waste. The evaporation and recondensation behavior of heavy metals caused their contents to differ with air pollution control equipment because of the temperature difference during gas venting. Among the heavy metals tested, Cd had the strongest tendency to transfer during incineration (T{sub Cd} = 69.5%) because it had the lowest melting point, followed by Cu, Ni, Pb and Zn. The exchangeable and residual fractions of heavy metals increased substantially in the incineration products compared with that of the input residues. Although the mass of residues from WEEE dismantling can be reduced by 70% by incineration, the safe disposal of the metal-enriched bottom and fly ashes is still required.

  2. Oxidative leaching of chromium from layered double hydroxides: Mechanistic studies

    Indian Academy of Sciences (India)

    A V Radha; P Vishnu Kamath

    2004-08-01

    The layered double hydroxide (LDH) of Zn with Cr on treatment with a hypochlorite solution releases chromate ions as a result of oxidative leaching by a dissolution–reprecipitation mechanism. The residue is found to be -Zn(OH)2. The LDH of Mg with Cr on the other hand is resistant to oxidative leaching. In contrast, a X-ray amorphous gel of the coprecipitated hydroxides of Mg and Cr yields chromate ions. These results suggest that the oxidation potential of Cr(III) in LDHs is determined by the nature of the divalent ion and the crystallinity of the phase while being unaffected by the nature of the intercalated anions.

  3. Thermal treatment of solid residues from WtE units: A review

    International Nuclear Information System (INIS)

    Highlights: • We review the thermal treatment methods for ashes and residues from WtE plants. • We review the results from extensive laboratory work on vitrification, melting and vaporization of ash. • We analyze the results from the extensive patent literature on thermal treatment. • We review industrial concepts for thermal treatment of ash. - Abstract: Thermal treatment methods of bottom ash, fly ash and various types of APC (air pollution control) residues from waste-to-energy plants can be used to obtain environmentally stable material. The thermal treatment processes are meant to reduce the leachability of harmful residue constituents, destroy toxic organic compounds, reduce residue volume, and produce material suitable for utilization. Fly ash and APC residues often have high levels of soluble salts, particularly chlorides, metals such as cadmium, lead, copper and zinc, and trace levels of organic pollutants such as dioxins and furans. Different thermal treatment methods can be used to either decompose or stabilize harmful elements and compounds in the ash, or separate them from the ash to get a material that can be safely stored or used as products or raw materials. In the present paper, thermal treatment methods, such as sintering, vitrification, and melting have been reviewed. In addition to a review of the scientific literature, a survey has been made of the extensive patent literature in the field

  4. Thermal treatment of solid residues from WtE units: A review

    Energy Technology Data Exchange (ETDEWEB)

    Lindberg, Daniel, E-mail: daniel.lindberg@abo.fi; Molin, Camilla, E-mail: camilla.molin@abo.fi; Hupa, Mikko, E-mail: mikko.hupa@abo.fi

    2015-03-15

    Highlights: • We review the thermal treatment methods for ashes and residues from WtE plants. • We review the results from extensive laboratory work on vitrification, melting and vaporization of ash. • We analyze the results from the extensive patent literature on thermal treatment. • We review industrial concepts for thermal treatment of ash. - Abstract: Thermal treatment methods of bottom ash, fly ash and various types of APC (air pollution control) residues from waste-to-energy plants can be used to obtain environmentally stable material. The thermal treatment processes are meant to reduce the leachability of harmful residue constituents, destroy toxic organic compounds, reduce residue volume, and produce material suitable for utilization. Fly ash and APC residues often have high levels of soluble salts, particularly chlorides, metals such as cadmium, lead, copper and zinc, and trace levels of organic pollutants such as dioxins and furans. Different thermal treatment methods can be used to either decompose or stabilize harmful elements and compounds in the ash, or separate them from the ash to get a material that can be safely stored or used as products or raw materials. In the present paper, thermal treatment methods, such as sintering, vitrification, and melting have been reviewed. In addition to a review of the scientific literature, a survey has been made of the extensive patent literature in the field.

  5. Application of accelerated carbonation on MSW combustion APC residues for metal immobilization and CO2 sequestration.

    Science.gov (United States)

    Cappai, G; Cara, S; Muntoni, A; Piredda, M

    2012-03-15

    The present study focuses on the application of an aqueous phase accelerated carbonation treatment on air pollution control (APC) residues from municipal solid waste combustion, aimed at assessing its influence on the environmental behaviour of the residue under concern, as well as the potential of the process in terms of sequestration of the CO2. APC residues are considered hazardous waste and must be treated before final disposal in order to achieve the immobilization/mobilization of critical contaminants such as heavy metals as well as mobilization of soluble salts. The treatment applied proved to be effective in reducing the mobility of Pb, Zn, Cr, Cu and Mo, the optimum final pH for the carbonated APC residues being in a range of 10-10.5, whilst a mobilization effect was noticed for Sb and no effect was assessed for chlorides. The effect of carbonation treatment on the contaminant release was further evaluated by means of a sequential extraction procedure, indicating that the distribution of contaminants on water soluble, exchangeable and carbonate fraction was modified after treatment. The CO2 sequestration potential assessed for the APC residues showed that the carbonation technology could be a technically viable option in order to reduce emissions from WtE plants. PMID:21601357

  6. Distribution of actinide elements in sediments: leaching studies

    International Nuclear Information System (INIS)

    Previous investigations have shown that Fe and Mn oxides and organic matter can significantly influence the behavior of Pu and other actinides in the environment. A sequential leaching procedure has been developed in order to investigate the solid phase distribution of the actinides in riverine and marine sediments. Seven different sedimentary fractions are defined by this leaching experiment: an exchangeable metals fraction, an organic fraction, a carbonate fraction, a Mn oxide fraction, an amorphous Fe fraction, a crystalline Fe oxide fraction and a lattice-held or residual fraction. There is also the option of including a metal sufide fraction. A preliminary experiment, analyzing only the metals and not the actinide elements, indicates that this leaching procedure (with some modifications) is a viable procedure. The subsequent data should result in information concerning the geochemical history and behavior of these actinide elements in the environment

  7. Ee-Leach(Low Energy Adaptive Clustering Hierarchy Modified Protocol

    Directory of Open Access Journals (Sweden)

    Nishita Payar,

    2014-05-01

    Full Text Available A wireless sensor network is made by many homogeneous and/or nodes which can sense data and communicate to each other. As energy is a scarce resource in WSN, the main issue is energy efficient routing. Many flat and hierarchical protocols have been projected to enhance the network lifetime. Low Energy Adaptive Clustering Hierarchy (LEACH protocol is a basic energy efficient hierarchical routing protocol in WSN. In LEACH, cluster heads are selected and cluster is formed by joining non cluster head nodes. Member nodes transmit the data to respective cluster head and the cluster head is conscientious to transmit the gathered and aggregated data directly to the base station. This paper examines the performance of the conventional LEACH protocol and gives an enhancement to it for energy efficiency. The proposed protocol considers many parameters like residual energy and distance from base station etc. for cluster head selection and energy efficient routing.

  8. Experimental Study of the Rhizobium and Iron Oxide Thiobacillus for Heap Leaching of Zinc Leaching Slag%根瘤菌与氧化铁硫杆菌堆浸锌浸出渣的试验研究

    Institute of Scientific and Technical Information of China (English)

    李勇; 邓兴; 金开胜; 杨光棣

    2012-01-01

    This paper adopts the rhizobium and thiobaeillus ferrooxidans respectively for heap leaching processing of hydrometallurgy of zinc leaching residue. Through the treatment of rhizobium with thiobacillus ferrooxidans, zinc leaching residue of zinc leaching rate is compared. The test results indicate that rhizobium treatment of zinc leaching residue of zinc leaching rate reaches 24.12 % and thiobacillus ferrooxidans treatment of zinc leaching residue of zinc leaching rate reaches 33.86 %. Treatment rate by thiobacillus ferrooxidans was significantly higher than that of rhizobium.%本文采用根瘤菌与氧化铁硫杆菌分别堆浸处理湿法冶金的锌浸出渣,通过比较根瘤菌与氧化铁硫杆菌处理的锌浸出渣的锌浸出率。试验结果表明,根瘤菌处理锌浸出渣锌浸出率达到了24.12%,而氧化铁硫杆菌处理的锌浸出渣锌浸出率达到了33.86%,氧化铁硫杆菌处理锌浸出渣的锌浸出率明显高于根瘤菌。

  9. Effects of carbonation and leaching on porosity in cement-bound waste.

    Science.gov (United States)

    Van Gerven, T; Cornelis, G; Vandoren, E; Vandecasteele, C

    2007-01-01

    Porosity is possibly an important parameter with respect to leaching of constituents from cement monoliths. During its lifetime, the pore structure of cementitious matrices changes due to carbonation and leaching. This paper discusses the effects of both accelerated carbonation and continuous leaching on the porosity, and, conversely, how porosity affects leaching properties. Two sample types are investigated: a mortar with MSWI-bottom ash substituting the sand fraction and a cement paste with 30 wt% of the cement substituted by a flue gas cleaning residue. The samples have been intensively carbonated in a 20% CO(2) atmosphere for up to 60 days and were subsequently leached. The porosity was investigated by mercury intrusion porosimetry. Accelerated carbonation decreases total porosity by 12% in the case of 60 days of treatment of bottom ash mortars, whereas continuous leaching during 225 days increases it by 16%. Both carbonation and leaching decrease the amount of smaller capillary pores. Carbonation decreases both porosity and pH. Decreasing porosity diminishes leaching of sodium and potassium, while the decrease in pH increases leaching. However, the former process dominates the latter, resulting in a net decreasing effect of carbonation on the release of sodium and potassium from these cement matrices. PMID:16843650

  10. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    Science.gov (United States)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2016-09-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  11. Thermal treatment of solid residues from WtE units: a review.

    Science.gov (United States)

    Lindberg, Daniel; Molin, Camilla; Hupa, Mikko

    2015-03-01

    Thermal treatment methods of bottom ash, fly ash and various types of APC (air pollution control) residues from waste-to-energy plants can be used to obtain environmentally stable material. The thermal treatment processes are meant to reduce the leachability of harmful residue constituents, destroy toxic organic compounds, reduce residue volume, and produce material suitable for utilization. Fly ash and APC residues often have high levels of soluble salts, particularly chlorides, metals such as cadmium, lead, copper and zinc, and trace levels of organic pollutants such as dioxins and furans. Different thermal treatment methods can be used to either decompose or stabilize harmful elements and compounds in the ash, or separate them from the ash to get a material that can be safely stored or used as products or raw materials. In the present paper, thermal treatment methods, such as sintering, vitrification, and melting have been reviewed. In addition to a review of the scientific literature, a survey has been made of the extensive patent literature in the field. PMID:25592372

  12. PAHs leaching test for solidified waste

    Energy Technology Data Exchange (ETDEWEB)

    Henzler, R.; Grathwohl, P. [Tuebingen Univ. (Germany). Center for Applied Geoscience

    2003-07-01

    The treatment of waste materials to allow recycling or safe disposal is a rapidly expanding business, but also subject to increasing public awareness of enviromental issues and tightening of the regularise governing in many countries. One of the most widely used treatment for wastes is stabilisation /solidification using a cement matrix to obtain a monolithic residue. The most common test procedure to assess the risks of contaminant release into water (seepage, surface and groundwater) is the so-called ''tank leaching test'' or ''diffusion test'' (NEN 7345, Mulder et al 2001, Hohberg et al 2000), in which a solidified specimen is leached with water during different periods of time. The tests are usually done at room temperatures between 20 C and 25 C. However, the temperature under natural conditions are lower resulting in lower contaminant release rates. (subsurface temperature: 5 C - 10 C). If the thermodynamics of the contaminant release, especially the activation energy of desorption and diffusion, is known, it is possible to estimate the contaminant release for lower temperatures, e.g. down to groundwater temperatures. In addition the test can be accelerated if performed at high temperatures.

  13. 从铜阳极泥中氧压浸出有价金属试验研究%Leaching of Valuable Metals From Copper Anode Slime by Oxygen Pressure-Acid Leaching Process

    Institute of Scientific and Technical Information of China (English)

    蔡创开; 庄荣传; 林鸿汉

    2015-01-01

    Leaching of valuable metals from copper anode slime by three oxygen pressure process was investigated .The distribution of copper ,tellurium ,selenium and silver in the processes were examined . The results show that by the direct oxygen pressure-acid leaching process ,selenium is partially leached out which is not conducive to enrich of selenium in leaching residues .The process of water leaching-oxygen pressure alkali leaching is lengthy and complex ,the silver is dispersed in the leaching solution . By water leaching-oxygen pressure acid leaching process ,under the conditions of temperature of 130℃ ,oxygen pressure of 0 .8 M Pa ,the leaching rate of copper ,tellurium and selenium are 98 .3% ,46 .8%and 0 .11% ,respectively ,and the silver is concentrated in leaching residues .So the water leaching-oxygen pressure acid leaching process is recommended to further research .%研究了采用3种加压氧化方式从铜阳极泥中浸出有价金属 ,考察了阳极泥中铜、碲、硒、银的走向.结果表明 :直接氧压酸浸 ,阳极泥中的硒被部分浸出 ,不利于集中回收 ;氧压碱浸工艺流程长 ,工艺复杂 ,银被分散 ;水浸—氧压酸浸过程中 ,控制体系温度130 ℃ ,氧压0 .8 M Pa ,铜浸出率达98 .3% ,碲浸出率为46 .8% ,硒浸出率仅0 .11% ,银集中在渣中 ,有利于下一步集中回收.3种工艺中 ,以水浸—氧压酸浸效果最佳.

  14. Risk of Leaching in Soils Amended by Compost and Digestate from Municipal Solid Waste

    OpenAIRE

    Marta García-Albacete; Ana M. Tarquis; M. Carmen Cartagena

    2014-01-01

    New European directives have proposed the direct application of compost and digestate produced from municipal solid wastes as organic matter sources in agricultural soils. Therefore information about phosphorus leaching from these residues when they are applied to the soil is increasingly important. Leaching experiments were conducted to determine the P mobility in compost and digestate mixtures, supplying equivalent amounts to 100 kg P ha−1 to three different types of soils. The tests were p...

  15. Effect of Harsh or Mild Extraction of Soil on Pesticide Leaching to Groundwater.

    Science.gov (United States)

    Boesten, Jos J T I

    2016-07-01

    Assessment of leaching to groundwater is an important aspect of pesticide risk assessment. The first leaching tier usually consists of simulations with leaching scenarios based on pesticide-soil properties derived from laboratory studies. Because the extractability of pesticide residues in such studies decreases with time, the harshness of the extraction method influences these pesticide-soil properties. This study investigates the effect of using a mild or harsh extraction method on simulated leaching to groundwater with consideration of substances with a range of half-lives and organic matter sorption coefficient values for selected leaching scenarios. The model for linking the concentrations of the mild and the harsh systems was based on laboratory studies with two pesticides and a Dutch sandy soil and was tested against Canadian field studies with atrazine (6-chloro-2-ethyl-4-isopropyl-1,3,5-triazine-2,4-diamine). The degradation rate and the aged-sorption parameters of each "mild" soil-substance system were derived from a hypothetical laboratory incubation study using prescribed parameter values for the corresponding "harsh" soil-substance system. Simulations were performed for three European leaching scenarios (United Kingdom, France, Portugal). For the best-guess parameter set, the leaching concentrations of the harsh system were approximately equal to those of the mild system at leaching concentrations greater than 1 μg L and were at most approximately a factor of two higher than those of the mild systems at mild leaching concentrations between 0.01 and 0.1 μg L. However, an extreme parameter set led to harsh leaching concentrations that were at most approximately 10 times higher than the mild leaching concentrations at levels between 0.01 and 0.1 μg L. PMID:27380081

  16. Air pollution control by economic incentives in the U.S.: Policy, problems, and progress

    Science.gov (United States)

    Lakhani, Hyder

    1982-01-01

    This paper deals with cost-effectiveness of the economic incentive policies of the bubble concept and offset credits relative to the policy of direct regulations of air emissions. The second section discusses single- and multi-plant bubbles, their adoption across regions and industries, the methods used to control emissions and the extent of savings in costs. We conclude that despite the delay resulting from duplication of review of state implementation plans by both the state and the Environmental Protection Agency, the required technological commands, the requirement to model air quality and the restrictions to permit bubbling only in the attainment areas, the policy is progressing successfully and should be encouraged by eliminating the restrictions. The third section analyzes the policy of emission offset credit, trading, and banking which can permit economic growth in nonattainment areas. It reviews the available literature, which deals only with aggregation of offsets across cities instead of individual offset trades. Progress by individual offset trades is analyzed in terms of the number of offsets, their acceptance across regions, the extent of reductions in emissions, and the classification of the offsets into internal and external trades. Comparison of estimated capital costs and prices of individual offsets with direct regulation costs reveals that the former are economical. We conclude that despite the problems of high tradeoff ratios, the short and uncertain life of the emission offset credits and the technological commands, the policy is progressing successfully and should be encouraged further by relaxing restrictions.

  17. Gas-phase advanced oxidation as an integrated air pollution control technique

    Directory of Open Access Journals (Sweden)

    Getachew A. Adnew

    2016-03-01

    Full Text Available Gas-phase advanced oxidation (GPAO is an emerging air cleaning technology based on the natural self-cleaning processes that occur in the Earth’s atmosphere. The technology uses ozone, UV-C lamps and water vapor to generate gas-phase hydroxyl radicals that initiate oxidation of a wide range of pollutants. In this study four types of GPAO systems are presented: a laboratory scale prototype, a shipping container prototype, a modular prototype, and commercial scale GPAO installations. The GPAO systems treat volatile organic compounds, reduced sulfur compounds, amines, ozone, nitrogen oxides, particles and odor. While the method covers a wide range of pollutants, effective treatment becomes difficult when temperature is outside the range of 0 to 80 °C, for anoxic gas streams and for pollution loads exceeding ca. 1000 ppm. Air residence time in the system and the rate of reaction of a given pollutant with hydroxyl radicals determine the removal efficiency of GPAO. For gas phase compounds and odors including VOCs (e.g. C6H6 and C3H8 and reduced sulfur compounds (e.g. H2S and CH3SH, removal efficiencies exceed 80%. The method is energy efficient relative to many established technologies and is applicable to pollutants emitted from diverse sources including food processing, foundries, water treatment, biofuel generation, and petrochemical industries.

  18. 76 FR 39357 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2011-07-06

    ... compound (VOC) emissions from architectural coating operations. We are proposing to approve local rules to... publicly available only at the hard copy location (e.g., copyrighted material), and some may not...

  19. 76 FR 75857 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control District

    Science.gov (United States)

    2011-12-05

    ... from architectural coatings and automotive refinishing operations. We are proposing to approve two... copy location (e.g., copyrighted material, large maps), and some may not be publicly available in... INFORMATION: This proposal addresses the following local rules: PCAPCD Rule 218, Architectural Coatings...

  20. 78 FR 37176 - Revisions to the California State Implementation Plan, San Diego Air Pollution Control District

    Science.gov (United States)

    2013-06-20

    ... from architectural coatings. We are proposing to approve a local rule to regulate these emission... available only at the hard copy location (e.g., copyrighted material, large maps), and some may not be... Architectural Coatings. In the Rules and Regulations section of this Federal Register, we are approving...

  1. Improving air pollution control policy in China--A perspective based on cost-benefit analysis.

    Science.gov (United States)

    Gao, Jinglei; Yuan, Zengwei; Liu, Xuewei; Xia, Xiaoming; Huang, Xianjin; Dong, Zhanfeng

    2016-02-01

    To mitigate serious air pollution, the State Council of China promulgated the Air Pollution Prevention and Control Action Plan in 2013. To verify the feasibility and validity of industrial energy-saving and emission-reduction policies in the action plan, we conducted a cost-benefit analysis of implementing these policies in 31 provinces for the period of 2013 to 2017. We also completed a scenario analysis in this study to assess the cost-effectiveness of different measures within the energy-saving and the emission-reduction policies individually. The data were derived from field surveys, statistical yearbooks, government documents, and published literatures. The results show that total cost and total benefit are 118.39 and 748.15 billion Yuan, respectively, and the estimated benefit-cost ratio is 6.32 in the S3 scenario. For all the scenarios, these policies are cost-effective and the eastern region has higher satisfactory values. Furthermore, the end-of-pipe scenario has greater emission reduction potential than energy-saving scenario. We also found that gross domestic product and population are significantly correlated with the benefit-cost ratio value through the regression analysis of selected possible influencing factors. The sensitivity analysis demonstrates that benefit-cost ratio value is more sensitive to unit emission-reduction cost, unit subsidy, growth rate of gross domestic product, and discount rate among all the parameters. Compared with other provinces, the benefit-cost ratios of Beijing and Tianjin are more sensitive to changes of unit subsidy than unit emission-reduction cost. These findings may have significant implications for improving China's air pollution prevention policy.

  2. 78 FR 6736 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control District

    Science.gov (United States)

    2013-01-31

    ... 27115) Days. LTAB 310 Minimum Drying Times 06/19/79 05/18/81 (46 FR 27115) LTAB 311 Exceptions to Rule... 310 Restricted Burning 06/19/79 05/18/81 (46 FR 27115) Days. MCAB/SVAB 312 Minimum Drying 06/19/79 05/18/81 (46 FR 27115) Times, Sections A, B, and E. MCAB/SVAB 312 Minimum Drying 05/20/85 02/03/87...

  3. [Application of analytical pyrolysis in air pollution control for green sand casting industry].

    Science.gov (United States)

    Wang, Yu-jue; Zhao, Qi; Chen, Ying; Wang, Cheng-wen

    2010-02-01

    Analytic pyrolysis was conducted to simulate the heating conditions that the raw materials of green sand would experience during metal casting process. The volatile organic compound (VOC) and hazardous air pollutant (HAP) emissions from analytical pyrolysis were analyzed by gas chromatograph-flame ionization detector/mass spectrometry (GC-FID/MS). The emissions from analytical pyrolysis exhibited some similarity in the compositions and distributions with those from actual casting processes. The major compositions of the emissions included benzene, toluene and phenol. The relative changes of emission levels that were observed in analytical pyrolysis of the various raw materials also showed similar trends with those observed in actual metal casting processes. The emission testing results of both analytic pyrolysis and pre-production foundry have shown that compared to the conventional phenolic urethane binder, the new non-naphthalene phenolic urethane binder diminished more than 50% of polycyclic aromatic hydrocarbon emissions, and the protein-based binder diminished more than 90% of HAP emissions. The similar trends in the two sets of tests offered promise that analytical pyrolysis techniques could be a fast and accurate way to establish the emission inventories, and to evaluate the relative emission levels of various raw materials of casting industry. The results of analytical pyrolysis could provide useful guides for the foundries to select and develop proper clean raw materials for the casting production. PMID:20391731

  4. 78 FR 37130 - Revisions to the California State Implementation Plan, San Diego Air Pollution Control District

    Science.gov (United States)

    2013-06-20

    ... direct final rule are encouraged to file a comment in response to the parallel notice of proposed... access'' system, and EPA will not know your identity or contact information unless you provide it in the... files should avoid the use of special characters, any form of encryption, and be free of any defects...

  5. Operation of Oil Burning Equipment and Incinerators. An Air Pollution Control Workbook, Preliminary Edition.

    Science.gov (United States)

    New Jersey State Dept. of Environmental Protection, Trenton. Bureau of Air Pollution Control.

    This workbook has been prepared for use by persons charged with the burning of fuels and waste products in the State of New Jersey. It is written for building superintendents, custodians, porters, handymen and operating engineers of public, apartment, commercial and office buildings. The manual emphasizes operating procedures that will help meet…

  6. 75 FR 8008 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2010-02-23

    ... construction sites, unpaved roads, and disturbed soils in open and agricultural areas. We are proposing action... prevent vehicular trespass and to stabilize disturbed soil on certain open areas. Agricultural operations... term ``disturbed surface area'' is used in several Regulation VIII rules but is never defined....

  7. 78 FR 922 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2013-01-07

    ... disturbed soils in open and agricultural areas in Imperial County. We are proposing to approve local rules... soil on open areas larger than 0.5 acres in urban areas, and larger than three acres in rural areas...) activity; Demonstrate BACM; Clarify the definition of disturbed surface area and conservation...

  8. 75 FR 39365 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2010-07-08

    ... construction sites, unpaved roads, and disturbed soils in open and agricultural areas in Imperial County. DATES... proposal TSD, section III.B.1. 2. Definition of ``Disturbed Surface'' The term ``disturbed surface area...). \\8\\ 75 FR 8008, 8011 and our proposal TSD, section III.B.3. 2. Unpaved Farm Roads and Traffic...

  9. 76 FR 5319 - Revisions to the California State Implementation Plan, Santa Barbara Air Pollution Control...

    Science.gov (United States)

    2011-01-31

    ...: Submit comments, identified by docket number EPA-R09-OAR- 2010-0860, by one of the following methods: 1... should avoid the use of special characters, any form of encryption, and be free of any defects or...

  10. 78 FR 21581 - Revisions to the California State Implementation Plan, Santa Barbara County Air Pollution Control...

    Science.gov (United States)

    2013-04-11

    ...- 2012-0828, by one of the following methods: 1. Federal eRulemaking Portal: www.regulations.gov . Follow... should avoid the use of special characters, any form of encryption, and be free of any defects or...

  11. APPLICATION OF GAME THEORY IN THE DESIGN OF OPTIMAL AIR POLLUTION CONTROL MEASURES

    Science.gov (United States)

    Methods of game theory are used to develop a technique for finding optimal solutions to air quality problems that involve multiple objectives. The technique is demonstrated using a hypothetical problem in which sites for two new power plants are sought that optimally satisfy five...

  12. Biotechnology as an alternative for carbon disulfide treatment in air pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, N.; Gallastegi, G.; Barona, A.; Gurtubay, L.; Elias, A. [Univ. of the Basque Country, Bilbao (Spain). Dept. of Chemical and Environmental Engineering; Gabriel Ibarra-Berastegi [Univ. of the Basque Country, Bilbao (Spain). Dept. of Nuclear Engineering and Fluid Mechanics

    2010-07-01

    The industry demand for CS{sub 2} has changed considerably over the last 2 decades and is expected to increase. This paper discussed the technical and financial feasibility of eliminating carbon disulphide (CS{sub 2}) from exhaust gases use biotechnology. The global emissions of this hazardous air pollutant are estimated to exceed 250,000 tonnes per year. However, the emission range depends on the source. The conventional technologies for treating CS{sub 2} emissions include thermal oxidation, thermo-catalytic processes or incineration. However, these technologies have drawbacks, such as high energy consumption and the generation of secondary by-products that require additional treatment. Recently, biotechnology was touted as an affordable, effective, and ecologically sound alternative to treat waste gases containing CS{sub 2}. Biological technologies based on microorganisms to biodegrade air pollutants overcome many of the disadvantages of conventional techniques and are particularly useful for the removal of relatively low concentrations of pollutants. The main properties, sources, and uses of CS{sub 2} were summarized in this paper along with alternative biotreatments for CS{sub 2}. Several applications of the technical and economical feasibility of biofilters and biotrickling filters were presented. Further research is required before their widespread industrial application. 72 refs., 3 tabs.

  13. Discharge and flow characteristics using magnetic fluid spikes for air pollution control

    International Nuclear Information System (INIS)

    This paper presents an investigation of the atmospheric discharge and flow characteristics using a magnetic fluid (MF) for an air cleaning device. High-voltage ac is applied between MF spikes formed under a magnetic field and a flat-plate electrode. These MF-spikes are stretched upward to the opposing electrode sharpening its tip until discharge is generated. Furthermore, MF droplets are ejected from the tips of the spikes (a phenomenon known as electrospray) depending on the MF properties and operating conditions. The atmospheric discharge characteristics were investigated by measuring the discharge current. The cleaning ability of the system was evaluated by measuring the produced ozone concentrations. (fast track communication)

  14. Proposals to enhance thermal efficiency programs and air pollution control in south-central Chile

    International Nuclear Information System (INIS)

    Major cities in South-central Chile suffer high levels of particulate matter PM10 and PM2.5 due to combustion of solid fuels for heating. Exposure to these air pollutants is recognized as a major contribution to ill health in the region. Here we discuss new strategies to reduce air pollution. Regulations and subsidies focusing on improved combustion by providing drier wood fuel and better stoves have been in effect since 2007. However, air pollution due to combustion of wood fuel has been steadily rising, along with reports on health consequences. The paper analyzes a survey of 2025 households in the city of Valdivia, which found that wood fuel quality, stove renewal, and awareness of programs are strongly affected by income level, and that higher consumption of wood fuel is found in households already having better stoves and drier wood fuel. The analysis suggests that regulations intended to improve combustion are influenced by user's behavior and have limited potential for lowering pollution. We conclude that thermal refurbishment has a larger potential for improvement, not yet been implemented as an energy policy for the majority. Here we propose improvements and additions to current programs to enhance effectiveness and cover the whole social spectrum. - Highlights: • High levels of PM2.5 from wood combustion affect cities of south-central Chile. • Current programs on dry wood fuel and stoves renewal have not reduced air pollution. • Real operation of wood stoves strongly depends on user's behavior. • Buildings' energy efficiency has greater potential for reducing emissions. • Retrofit prevents degradation of native forest and improves indoor temperature

  15. 75 FR 27975 - Revisions to the California State Implementation Plan; Imperial County Air Pollution Control...

    Science.gov (United States)

    2010-05-19

    ... based on maintaining a target soil moisture content and manure removal and management practices designed... rule contains an adequate test method for determining moisture content of the livestock corrals... previous version of Rule 420 (see 68 FR 8839). CARB has made no subsequent submittals of the rule. C....

  16. Air pollution control techniques and a case study of industrial air emissions

    International Nuclear Information System (INIS)

    Air pollutants are the most dangerous type of pollution and they effect our environment the worst. The main air pollutants are CO/sub 2/, CO, NOx, SOx and particulate matter. These pollutants are causing some major environmental and health concerns. There are number of techniques to control these emissions to the atmosphere. The flue gas data of boilers and generators from ICI polyester industry is also included in this paper. The techniques in use to control the pollutants are discussed. One of the most common techniques is the switching of the fuel. The Natural gas emits almost 30 percent less carbon dioxide than oil, and just under 45 percent less carbon dioxide than coal. Emissions of particulates from natural gas combustion are 90 percent lower than from the combustion of oil, and 99 percent lower than burning coal. Natural gas emits virtually no sulfur dioxide, and upto 80 percent less nitrogen oxides than the combustion of coal. Similarly, use of compressed natural gas in vehicle reduces the amount of these emissions considerably. The other methods for the control and reduction of these emissions are combustion control techniques, Flue gas treatment and Fuel re-burning. NOx can be reduced considerably by combustion control techniques like Low excess air, staged air combustion, staged fuel combustion, external flue gas recirculation, Fuel induced recirculation and steam/water injection. The flue gas treatments like selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) are also used for reduction of NOx. (author)

  17. 76 FR 60405 - Revisions to the California State Implementation Plan, Santa Barbara Air Pollution Control...

    Science.gov (United States)

    2011-09-29

    ... Control District, Sacramento Municipal Air Quality Management District and South Coast Air Quality Management District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is... Municipal Air Quality Management District (SMAQMD) and South Coast Air Quality Management District...

  18. Air pollution control measures of the electricity industry in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    The pollution of air with SO2 and NOx constitutes a problem which can be regionally delimited and can be solved by a harmonization of pollution control standards at the highest possible level. The growing CO2 concentration in the atmosphere, however, has possibly a strong impact on the global climate. In this context it has to be borne in mind in particular that it will be impossible to undo environmental damage once it has arisen. Once lasting changes of the world climate have been caused by the increased CO2 concentration, all the pollution control efforts will not achieve any short-term success but will produce desired effects only with a time-lag of decades at the earliest. All measures by a country to contain CO2 emissions on a national level are almost ineffective if a reduction of CO2 emissions is not aimed at by international agreements at the same time. All nations are therefore called upon to help solve the CO2 problem. National single-handed approaches are equally inappropriate as the oft-heard reference to the just marginal contribution by the respective countries to global CO2 emissions. In light of their possibilities and the magnitude of the problem, it is precisely the industrial nations that have the duty not only to cut CO2 emissions in their own countries but also to give the developing countries the assistance required to keep the CO2 content of the atmosphere from rising further. (author). 9 figs

  19. AIR POLLUTION CONTROL THROUGH KILN RECYCLING BY-PASS DUST IN A CEMENT FACTORY

    Directory of Open Access Journals (Sweden)

    F. Mohsenzadeh, J. Nouri, A. Ranjbar, M. Mohammadian Fazli, A. A. Babaie

    2006-01-01

    Full Text Available Air pollution is a major problem in the industrial areas. Cement dust is one of the important environmental pollutants. In this study the possibility of dust recycling especially kiln dust which has significant importance regarding air pollution in the cement plant, was examined. Tehran cement factory is one of the most important Iranian factories which is located in Tehran. This factory produces high volume of pollutants that are released to in environment. The possibility of reusing of kiln by pass returned dust has been examined in this factory. Different percentages of kiln by-pass dust of this factory were added to products and outcomes of its presence in parameters such as chemical compound, granulation, primary and final catch time, volume expansion, consumed water and resistance of mortar were surveyed. The result indicated that by adding the amounts of 3-8 dust the mortar resistance increase, but adding more than 15%, the mortar resistance has been decreased. Survey in consumed water proved that adding dust to cement, the trend for consuming water is decreased. After dust addition dust, primary and final catch time were compared in different samples and data which showed decrease in dust added samples. Cements with dust added showed increase in auto clave expansion. Overally, results proved that, the best percentage rate of dust addition to the cement was 15%.

  20. Spatial flow influence factor: A novel concept for indoor air pollutant control

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper puts forward a novel concept, the spatial flow influence factor (SFIF), which provides a new insight into the airflow structure. This concept is very helpful in the control of indoor air pollutants since: (1) for a given indoor airflow and given sources of volatile organic compounds (VOCs), the optimal arrangement of the VOC sources can easily be obtained; (2) for given positions of VOC sources and occupied regions (or target regions), the optimal indoor airflow pattern or organization can be determined; (3) the SFIF for an indoor space can also be regarded as the indoor air safety index of that space. To illustrate this concept, we present several examples of applying a SFIF to indoor air VOC control.

  1. 75 FR 2079 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Science.gov (United States)

    2010-01-14

    ... and Executive Order Reviews I. Proposed Action On July 14, 2009 (74 FR 33948), EPA proposed a limited... Matter, Comit West Goshen, Comit Unido de Plainview, Comit Residentes Organizados al Servicio del... based on our judgment of how the numerous factors, taken together, compare to RACT policy and...

  2. U.S. EPA-developed air-pollution control technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, V.S. [Seoul Sharp-Center for the Environment & Development, Research Triangle Park, NC (United States)

    1994-09-01

    The U.S. Environmental Protection Agency has licensed, for marketing on a world-wide exclusive basis, five air pollution technologies that utilize electrostatic precipitators. The technologies are the SUPER ESP, the reentrainment suppressor, spray drying within an existing ESP for simultaneous sulphur dioxide and particulate matter capture (E-SO{sub x}), electrostatic fabric filtration (ESFF), and retrofit electrostatic filtration (REF). The technical and operational capabilities of these technologies are described. 14 refs., 10 figs.

  3. Commercialization and development of U.S. EPA-developed air pollution control technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lee, V.S. [Seoul Sharp-Center for the Environment & Development, Research Triangle Park, NC (United States)

    1994-09-01

    Several air pollution technologies that are related to electrostatic precipitators and were developed by the U.S. Environmental Protection Agency, have been licensed for marketing. The five technologies are the SUPER ESP, the reentrainment suppressor, spray drying within an existing ESP (E-SO{sub x}), retrofit electrostatic filtration (REF), and electrostatically augmented fabric filtration (ESFF). A marketing strategy for these technologies is described. 1 ref., 1 fig.

  4. Effect of inlet temperature on the performance of a catalytic reactor. [air pollution control

    Science.gov (United States)

    Anderson, D. N.

    1978-01-01

    A 12 cm diameter by 15 cm long catalytic reactor was tested with No. 2 diesel fuel in a combustion test rig at inlet temperatures of 700, 800, 900, and 1000 K. Other test conditions included pressures of 3 and 6 x 10 to the 5th power Pa, reference velocities of 10, 15, and 20 m/s, and adiabatic combustion temperatures in the range 1100 to 1400 K. The combustion efficiency was calculated from measurements of carbon monoxide and unburned hydrocarbon emissions. Nitrogen oxide emissions and reactor pressure drop were also measured. At a reference velocity of 10 m/s, the CO and unburned hydrocarbons emissions, and, therefore, the combustion efficiency, were independent of inlet temperature. At an inlet temperature of 1000 K, they were independent of reference velocity. Nitrogen oxides emissions resulted from conversion of the small amount (135 ppm) of fuel-bound nitrogen in the fuel. Up to 90 percent conversion was observed with no apparent effect of any of the test variables. For typical gas turbine operating conditions, all three pollutants were below levels which would permit the most stringent proposed automotive emissions standards to be met.

  5. 76 FR 39303 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2011-07-06

    ... Organic Emissions from Existing Stationary Sources, Volume I: Control Methods for Surface Coating... volatile organic compound (VOC) emissions from architectural coating operations. We are approving local... for this action is available electronically at http://www.regulations.gov and in hard copy at...

  6. 76 FR 71922 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control...

    Science.gov (United States)

    2011-11-21

    ... Coating of Flat Wood Paneling), and SMAQMD Rule 451 (Surface Coating of Miscellaneous Metal Parts and... volatile organic compound (VOC) emissions from coatings and strippers used on wood products, wood paneling... available electronically at http://www.regulations.gov and in hard copy at EPA Region IX, 75...

  7. Study of Mass Oxygen Transfer in a Biotrickling Filter for Air Pollution Control

    OpenAIRE

    San-Valero, Pau; Gabaldón García, Carmen; Peñarrocha Oltra, Josep Manuel; Pérez Gil, María del Carmen

    2012-01-01

    Biotrickling filtration is a potential and cost effective alternative for the treatment of volatile organic compound (VOC) emissions in air, so it is necessary to deepen into the key aspects of design and operation for the optimization of this technology. One of these factors is the oxygen mass transfer of the process. This study would facilitate the selection of the packing material and the mathematical modelling and simulation of bioreactors. Four plastic packing materials with ...

  8. New Application of Seawater and Electrolyzed Seawater in Air Pollution Control of Marine Diesel Engine

    Science.gov (United States)

    An, Sukheon; Nishida, Osami

    It is the purpose of this paper to introduce the usage of seawater and its electrolysis for the exhaust emission control in marine diesel engines. First, with using only seawater that is naturally alkaline (pH typically around 8.1), the SO2 and SO3 are absorbed by relatively high solubility compared to other components of exhaust pollutants, and PMs (Particulate Matter) are removed through direct contact with the sprayed seawater droplets. Besides, the electrolyzed alkaline seawater by electrolysis, which contains mainly NaOH together with alkali metal ions (i. e. Na+, Mg2+, Ca2+), is used as the absorption medium of NOx and CO2. Conditionally, before the NOx absorption treatment with using the alkaline seawater, nitric oxide (NO) must be adequately oxidized to nitrogen dioxide (NO2) by the acidic seawater in order to increase NOx absorption rate into the alkaline seawater. Because NOx absorption is the most suited to conditions when both volume fractions (NO: NO2 ratio) are of equal portions. Finally, this research would also plan to treat the effluent by applying electro-dialysis and electro-flotation techniques in the future. The way to reduce emissions from the marine diesel engines is to make it attractive from an operating perspective, as well as an environmental perspective.

  9. 78 FR 896 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2013-01-07

    ... Submitted ICAPCD 400.2 Boilers, Process Heaters and 02/23/10 07/20/10 Steam Generators. We proposed to... Register on April 27, 2012 and concerns oxides of nitrogen (NO x ) emissions from certain boilers, process heaters and steam generators. We are approving a local rule that regulates these emission sources...

  10. 76 FR 67366 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control...

    Science.gov (United States)

    2011-11-01

    ... PCAPCD 231 Industrial, 10/09/97 03/17/09 Institutional and Commercial Boiler, Steam Generator and Process... carbon monoxide (CO) from boilers, steam generators and process heaters fueled on liquid or gas fuels..., Institutional, and Commercial Boilers, Steam Generators, and Process Heaters'', CARB (July 18, 1991)....

  11. 77 FR 25109 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Science.gov (United States)

    2012-04-27

    ... X ) emissions from certain boilers, process heaters and steam generators. We are approving a local... Boilers, Steam Generators, and Process Heaters,'' CARB, July 18, 1991. 7. ``Alternative Control Techniques... 1--Submitted Rule Local agency Rule No. Rule title Adopted Submitted ICAPCD 400.2 Boilers,...

  12. 77 FR 67322 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control District

    Science.gov (United States)

    2012-11-09

    ... Retrofit Control Technology for Industrial, Institutional, and Commercial Boilers, Steam Generators, and... biomass boilers. We are approving a local rule that regulates these emission sources under the Clean Air.... Table 1--Submitted Rule Local agency Rule No. Rule title Amended Submitted PCAPCD 233 Biomass Boilers...

  13. 76 FR 67396 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control District

    Science.gov (United States)

    2011-11-01

    ... Commercial Boiler, Steam Generator and Process Heaters, Rule 242, Stationary Internal Combustion Engines, Rule 246, Natural Gas-Fired Water Heaters, and Rule 414, Water Heaters, Boilers and Process Heaters... commercial boilers, stationary internal combustion engines and water heaters. We are proposing to...

  14. 76 FR 54993 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control District

    Science.gov (United States)

    2011-09-06

    ... emissions of NO X from biomass boilers and steam generators. EPA's technical support document (TSD) has more... concern oxides of nitrogen (NO X ) emissions from biomass fuel-fired boilers. We are proposing action on a... title Amended Submitted PCAPCD 233 Biomass Boilers......... 12/10/09 05/07/10 On June 8, 2010,...

  15. Gas-phase advanced oxidation as an integrated air pollution control technique

    OpenAIRE

    Getachew A. Adnew; Carl Meusinger; Nicolai Bork; Michael Gallus; Mildrid Kyte; Thomas Rosenørn; Johnson, Matthew S.; Vitalijs Rodins

    2016-01-01

    Gas-phase advanced oxidation (GPAO) is an emerging air cleaning technology based on the natural self-cleaning processes that occur in the Earth’s atmosphere. The technology uses ozone, UV-C lamps and water vapor to generate gas-phase hydroxyl radicals that initiate oxidation of a wide range of pollutants. In this study four types of GPAO systems are presented: a laboratory scale prototype, a shipping container prototype, a modular prototype, and commercial scale GPAO installations. The GPAO s...

  16. 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 insecticides. The repeatability of the breakthrough curves shows that both DNT and IMD are reproducible between runs, whereas, THM shows some inconsistency. Leaching behavior of 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.

  17. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    Institute of Scientific and Technical Information of China (English)

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  18. 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 t

  19. The removal of mercury from solid mixed waste using chemical leaching processes

    International Nuclear Information System (INIS)

    The focus of this research was to evaluate chemical leaching as a technique to treat soils, sediments, and glass contaminated with either elemental mercury or a combination of several mercury species. Potassium iodide/iodine solutions were investigated as chemical leaching agents for contaminated soils and sediments. Clean, synthetic soil material and surrogate storm sewer sediments contaminated with mercury were treated with KI/I2 solutions. It was observed that these leaching solutions could reduce the mercury concentration in soil and sediments by 99.8%. Evaluation of selected posttreatment sediment samples revealed that leachable mercury levels in the treated solids exceeded RCRA requirements. The results of these studies suggest that KI/I2 leaching is a treatment process that can be used to remove large quantities of mercury from contaminated soils and sediments and may be the only treatment required if treatment goals are established on Hg residual concentrations in solid matrices. Fluorescent bulbs were used to simulate mercury contaminated glass mixed waste. To achieve mercury contamination levels similar to those found in larger bulbs such as those used in DOE facilities a small amount of Hg was added to the crushed bulbs. The most effective agents for leaching mercury from the crushed fluorescent bulbs were KI/I2, NaOCl, and NaBr + acid. Radionuclide surrogates were added to both the EPA synthetic soil material and the crushed fluorescent bulbs to determine the fate of radionuclides following chemical leaching with the leaching agents determined to be the most promising. These experiments revealed that although over 98% of the dosed mercury solubilized and was found in the leaching solution, no Cerium was measured in the posttreatment leaching solution. This finding suggest that Uranium, for which Ce was used as a surrogate, would not solubilize during leaching of mercury contaminated soil or glass

  20. 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

  1. 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.

  2. 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. PMID:26365318

  3. Evaluation of contaminant release from solidified/stabilized municipal waste combustor residues for disposal and utilization

    International Nuclear Information System (INIS)

    Solidification/stabilization of municipal waste combustor residues is being considered for treatment of municipal waste combustion residues prior to disposal or utilization. Traditionally, contaminant release has been evaluated based on regulatory leach tests such as EP Toxicity or TCLP. Five S/S. processes, applied to bottom ash, combined ash and APC residues, each were evaluated using five different leaching procedures. The set of leaching procedures selected was designed to provide an understanding of contaminant release under differing potential management scenarios. This paper will discuss testing results and implications for evaluation of MWC residue utilization

  4. 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.

  5. Availability and leaching of nitrogen in two typical soils of Pontes e Lacerda, MT, treated with bovine rumen residueDisponibilidade e lixiviação de nitrogênio em dois solos típicos de Pontes e Lacerda, MT, tratados com resíduo ruminal bovino

    Directory of Open Access Journals (Sweden)

    Fernando Luiz Silva

    2013-09-01

    Full Text Available High production of waste during the slaughter of cattle increases the need to promote their correct utilization. In this study, the availability and leaching of nitrogen (NO3- and NH4+ after bovine rumen residue (BRR incorporation was evaluated in 2 typical soils of Pontes e Lacerda, MT: a distrophic Red Latosol and a eutrophic Yellow-Red Argisol. The experiment was conducted in a greenhouse at the University of State of Mato Grosso, UNEMAT, between December 2009 and March 2010. The samples were undisturbed soil in PVC tubes (length 40 cm; diameter, 10 cm, in which doses of BRR were added to provide 0, 50, 100, and 400 kg N ha-1 and urea was added to provide 400 kg N ha-1. Each treatment was performed using 4 replicates. The columns were irrigated weekly, and the leachate was collected and stored for analysis. After the experiment, soil samples were collected from 10 to 10 cm and the NO3- and NH4+ concentrations were determined. The use of BRR resulted in higher potential availability of N in distrophic Red Latosol, while in the eutrophic Yellow-Red Argisol, BRR could not supply adequate amount of nitrogen to the soil within the study period. In terms of N leaching, the distrophic Red Latosol has higher retention capacity for NO3- and lower retention capacity for NH4+ than eutrophic Yellow-Red Argisol; however, the levels of NO3- and NH4+ in the leachate collected from the 2 soils were within the standard values established by Resolution Conama 357/2005. The use of BRR as compared to the use of urea resulted in a lower risk of leaching N.A alta produção de resíduos durante o abate de bovinos aumenta a necessidade de promover a sua correta utilização. Neste estudo, a disponibilidade e a lixiviação de N (nitrato e amônio, após a incorporação resíduo ruminal bovino (RRB, foi avaliada em dois solos típicos de Pontes e Lacerda, MT: um Latossolo Vermelho distrófico e um Argissolo Vermelho-Amarelo eutrófico. O experimento foi conduzido

  6. Uranium leaching by fungal metabolite

    International Nuclear Information System (INIS)

    To explore new means of bioleaching, one strain of high-yielding fungi-Aspergillus niger which could produce organic acids was separated and purified from soil samples of uranium mine. The influence of cultural temperature, initial pH value, inoculum sizes on its growth characteristics were carried out. And the tests of uranium leaching of metabolin of Aspergillus niger were operated. On these tests, the effects of metabolin of Aspergillus niger with different pH value produced in the diverse culture temperature on uranium leaching were investigated. The results show that this strain of Aspergillus niger can grow best under the following conditions: the temperature is 37℃, the initial pH value is 7.0, the inoculum sizes is 2% (the OD value of the spores solution is 0.06). The uranium extraction effects relative to the final pH value of the cultures. and the maximum leaching rates is 83.05% when the pH value is 2.3. (authors)

  7. 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.

  8. Mesophilic leaching of copper sulphide sludge

    Directory of Open Access Journals (Sweden)

    VLADIMIR B. CVETKOVSKI

    2009-02-01

    Full Text Available Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 µm in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32 °C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

  9. Underground leaching of uranium ores

    International Nuclear Information System (INIS)

    Large amounts of low-grade U ore, not worth processing by conventional methods, are to be found at many sites in mine pillars, walls, and backfilling. Many proven deposits are not being mined because the geological conditions are difficult or the U ore is of relatively low grade. Factors such as radioactive emission, radon emanation, and the formation of radioactive dust give rise to health hazards. When U ores are treated above ground, enormous quantities of solid and liquid radioactive waste and mining spoil accumulate. The underground leaching of U is a fundamentally different kind of process. It is based on the selective dissolving of U at the place where it occurs by a chemical reagent; all that reaches the ground surface is a solution containing U, and after extraction of the U by sorption the reagent is used again. The main difficult and dangerous operations associated with conventional methods (excavation; extraction and crushing of the ore; storage of wastes) are avoided. Before underground leaching the ore formation has to be fractured and large ore bodies broken down into blocks by shrinkage stopping. These operations are carried out by advanced machinery and require the presence underground of only a few workers. If the ore is in seams, the only mining operation is the drilling of boreholes. The chemical reagent is introduced under pressure through one set of boreholes, while the U bearing solution is pumped out from another set. The process is monitored with the help of control boreholes. After extraction of the U by sorption, the reagent is ready to be used again. Very few operations are involved and insignificant amounts of dissolved U escape into the surrounding rock formations. Experience has shown that underground leaching reduces the final cost of the U metal, increases productivity, reduces capital expenditure, and radically improves working conditions

  10. Method of continuous pressure leaching of ores

    International Nuclear Information System (INIS)

    Ore leaching, especially suspensions of ground ore or fine ore fractions from physical treatment was divided into two operations. The former, i.e., ore mixing with technical grade concentrated sulfuric acid proceeded in a separate mixer. The mixture was then transported into an autoclave where the actual leaching proceeded for 2 to 4 hours. The extracted mixture was discharged through the autoclave bottom. The leaching autoclave used can be without any inner structures. The separation of mixing from the actual leaching allows processing ores with high levels of clay components, increasing operating reliability of the facility, reducing consumption of special structural materials and energy, and increasing process efficiency. (E.S.)

  11. Optimization Study on the Leaching of High Iron-Bearing Zinc Calcine After Reduction Roasting

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Qin, Wenqing; Zheng, Yongxing; Luo, Honglin

    2016-02-01

    The selective leaching of zinc from high iron-bearing zinc calcine after reduction roasting was optimized by Taguchi experimental design method. The experimental parameters and their ranges were 303 to 343 K (30 to 70 °C) for leaching temperature ( T), 7 to 15 mL/g for liquid/solid ratio ( L/ S), 70 to 150 g/L for H2SO4 concentration ( C), 5 to 25 minutes for time ( t), and 100 to 500 rpm for stirring speed ( R). The results show that the optimum conditions were 303 K (30 °C), 9 mL/g, 110 g/L, 20 minutes, and 400 rpm, respectively. Under these conditions, about 92.81 pct Zn was extracted and more than 86 pct Fe was reported into the leach residue. L/ S and C had significant effects on the extractions of zinc and iron, while t and R had no significant effects, and T had significant effect on iron extraction but negligible effect on zinc extraction. This indicates that diffusion was not a major control step of the leaching process, and the dissolution of iron was controlled by chemical reaction. The interactive effects of parameters were negligible. The leach residue was mainly composed of Fe3O4 and ZnS, and its particle size was very fine.

  12. 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

  13. 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.

  14. Leaching properties of electric arc furnace dust prior/following alkaline extraction.

    Science.gov (United States)

    Orescanin, Visnja; Mikelić, Luka; Sofilić, Tahir; Rastovcan-Mioc, Alenka; Uzarević, Krunoslav; Medunić, Gordana; Elez, Loris; Lulić, Stipe

    2007-02-15

    This study was carried out to determine the appropriate treatment of electric arc furnace (EAF) dust prior to permanent disposal. The total heavy metal content as well as heavy metal leaching from EAF dust was investigated in five composite samples obtained from three Croatian and Slovenian steelworks. In order to recover zinc and reduce its leaching from the dust, all five samples were submitted to alkaline extraction with 10 M NaOH. Reduction of Cr (VI) to Cr(III) was conducted using FeSO4 x 7H2O solution. The elements Mn, Fe, Cu, Ni, and notably Zn and Pb, exhibited highest mobility during toxicity characteristic leaching procedure (TCLP). Comparing to TCLP extracts of initial EAF dust, zinc was found to be over 15 times lower and lead over 200 times lower in TCLP extracts of EAF dust processed by the alkaline leaching method. Since Cr (VI) exceeded its permissible level in the DIN 38414-S4 extracts of both initial and alkaline digested dust, its reduction to Cr (III) prior to permanent disposal is necessary. The recovery of zinc from EAF dust treated with alkaline agent ranged from 50.3% to 73.2%. According to phase analysis, recovery yield showed dependence on zincite/franklinite ratio. The results of the study indicate that permanent disposal of EAF dust require the following procedure: alkaline digestion (followed by leachate purification and alkaline zinc electrolyses), chromate reduction (if necessary), solidification of leaching residue and its testing using the leaching analyses.

  15. Mineralogical and chemical investigations of abiotic hydrogen development in incinerator residues; Mineralogische und chemische Untersuchungen zur abiotischen Wasserstoffentwicklung in Muellverbrennungsrueckstaenden

    Energy Technology Data Exchange (ETDEWEB)

    Magel, G.

    2003-07-01

    The monofill of Waldering is the oldest monofill in Bavaria for residues of a municipal solid waste incinerator (MSWI). Bottom ash (BA) and residues of the air pollution control system (APC) from the MSWI in Rosenheim have been deposited since 1976. After the first section was entirely filled, it was covered with a landfill liner and cap, according to the German law for waste treatment. During final operations on the landfill liner a deflagration occurred. The analysis of the landfill gas revealed that hydrogen gas was produced within the landfill body. Due to the sealing, the hydrogen gas could not diffuse to the atmosphere but concentrates within the landfill. Above a concentration of 4%, hydrogen is an explosive gas in the presence of oxygen. Abiotic hydrogen generation in MSWI-residues has been noted in only a few studies which conclude that hydrogen production largely terminates after three months and therefore can be neglected in the long range. However, the occurrence of the long-term hydrogen production in Waldering contradicts these statements. Landfill gas from another landfill for MSWI-residues, situated in Franklin, New Hampshire (USA), contains 5.1% hydrogen. Therefore hydrogen production in a monofill is not unique to Waldering. Deposited material from both monofills has been analysed and compared to fresh material. Owing to different methods of deposition, the BA and APC-residues of the monofill of Waldering were investigated separately whereas composite samples of BA and APC-residues were analysed from the monofill of Franklin. The experimental data of this study - in agreement with some literature studies - show that the production of hydrogen in MSWI-residues is due to hydration reactions of non-noble metals, especially aluminium. (orig.)

  16. Leaching studies for tin recovery from waste e-scrap.

    Science.gov (United States)

    Jha, Manis Kumar; Choubey, Pankaj Kumar; Jha, Amrita Kumari; Kumari, Archana; Lee, Jae-Chun; Kumar, Vinay; Jeong, Jinki

    2012-10-01

    Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50 g/L and temperature 90°C in mixing time 165 min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68 kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60 min and pulp density 50 g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45 min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.

  17. COMPARE AND ANALYSES OF OPTIMIZED R-LEACH WITH LEACH ALGORITHM IN WSN

    Directory of Open Access Journals (Sweden)

    Tarun Sharma

    2015-11-01

    Full Text Available Wireless sensor networks are composed of numerous small charge, little power devices with sensing, local processing and wireless communication capabilities. Minimizing energy consumption and maximizing network lifespan are significant issues in the design of routing protocols for sensor networks. In this paper, we analyses the efficiency of LEACH protocol in extending the existence for energy-constrained wireless sensor networks. Based on LEACH protocol, an enhanced protocol termed as R- LEACH is proposed which aims to diminish energy consumption within the wireless sensor networks. The simulation results suggest R-LEACH protocol could equilibrium network energy consumption and extend the network lifecycle more successfully as compared to LEACH.

  18. 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...

  19. Atrazine leaching from biochar-amended soils.

    Science.gov (United States)

    Delwiche, Kyle B; Lehmann, Johannes; Walter, M Todd

    2014-01-01

    The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain.

  20. Atrazine leaching from biochar-amended soils.

    Science.gov (United States)

    Delwiche, Kyle B; Lehmann, Johannes; Walter, M Todd

    2014-01-01

    The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain. PMID:24129000

  1. PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD

    Science.gov (United States)

    Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...

  2. Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

    International Nuclear Information System (INIS)

    A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

  3. Leaching of tritium from a cement composite

    International Nuclear Information System (INIS)

    Leaching of tritium from cement composites into an aqueous phase has been studied to evaluate the safety of incorporation of the tritiated liquid waste into cement. Leaching tests were performed by the method recommended by the International Atomic Energy Agency. The Leaching fraction was measured as functions of waste-cement ratio (Wa/C), temperature of leachant and curing time. The tritium leachability of cement in the long term test follows the order: alumina cement portland cement slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than synthetic sea water. The amount leached of tritium from a 200 l drum size specimen was estimated on the basis of the above results. (author)

  4. Rule of oxygen transmission in dump leaching

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    According to the chemical equations, the flux and concentration of oxygen required during bacterial leaching sulfuric mineral were investigated; the rule of air bubble transmitted in granular was researched in the Dump Leaching Plant of Dexing Copper Mine. The results show that lack of oxygen in dump leaching is the critical factor of restricting leaching reaction. Pyrite is the primary oxygen-consuming mineral in bioleaching. When its content is too high, it needs a great deal of oxygen for reaction and competes for the finite oxygen with objective minerals, and thus the leaching velocity decreases greatly. The average size of ore particles and diameter of bubbles are the key parameters affecting the mass transfer coefficient. Reverse analysis was adopted, and it shows that 44.8 m3 air per unit ore can meet the requirement of production if the molar ratio of pyrite to chalcopyrite is 10.

  5. LEACH Algorithm Based on Load Balancing

    Directory of Open Access Journals (Sweden)

    Wangang Wang

    2013-09-01

    Full Text Available This paper discusses advantages of LEACH Algorithm and the existing improved model which takes the famous hierarchy clustering routing protocol LEACH Algorithm as researching object. Then the paper indicates the problem that in the algorithm capacity factor of cluster head node is not taken into account leading the structure of clusters to be not so reasonable. This research discusses an energy-uniform cluster and cluster head selecting mechanism in which “Pseudo cluster head” concept is introduced in order to coordinate with “Load Monitor” Mechanism and “Load Leisure” Mechanism to maintain load balancing of cluster head character and stability of network topology. On the basis of LEACH Protocol improving algorithm of LEACH-C, CEFL and DCHS. NS2 simulation instrument is applied to do simulation analysis on the improved algorithm. Simulation result shows that LEACH-P Protocol effectively increase energy utilization efficiency, lengthens network lifetime and balances network load.  

  6. Bacteria heap leaching test of a uranium ore

    International Nuclear Information System (INIS)

    Column bioleaching test of a uranium ore was carried out. The optimum acidity, spraying intensity, spray-pause time ratio were determined. The potential, Fe and U concentrations in the leaching process were investigated. The effect of bacteria column leaching was compared with that of acid column leaching. The results show that bacteria column leaching can shorten leaching cycle, and the leaching rate of uranium increases by 9.7%. (authors)

  7. Dynamic leaching test of personal computer components.

    Science.gov (United States)

    Li, Yadong; Richardson, Jay B; Niu, Xiaojun; Jackson, Ollie J; Laster, Jeremy D; Walker, Aaron K

    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. PMID:19616380

  8. Dissolution of Nickel in Copper Residue Generated from Nickel Matte Refining

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The dissolution behavior of nickel during the oxygen-chloride leaching of the copper residue was investigated.Technological variables of the leaching,including oxygen flow rate,concentrations of chloride and sulfuric acid,and temperature,were discussed.

  9. Biogas production from energy crops and crop residues

    OpenAIRE

    Lehtomäki, Annimari

    2006-01-01

    The feasibility of utilising energy crops and crop residues in methane production through anaerobic digestion in boreal conditions was evaluated in this thesis. Potential boreal energy crops and crop residues were screened for their suitability for methane production, and the effects of harvest time and storage on the methane potential of crops was evaluated. Co-digestion of energy crops and crop residues with cow manure, as well as digestion of energy crops alone in batch leach bed reactors ...

  10. Reductive leaching of low-grade manganese ore with pre-processed cornstalk

    Science.gov (United States)

    Yi, Ai-fei; Wu, Meng-ni; Liu, Peng-wei; Feng, Ya-li; Li, Hao-ran

    2015-12-01

    Cornstalk is usually directly used as a reductant in reductive leaching manganese. However, low utilization of cornstalk makes low manganese dissolution ratio. In the research, pretreatment for cornstalk was proposed to improve manganese dissolution ratio. Cornstalk was preprocessed by a heated sulfuric acid solution (1.2 M of sulfuric acid concentration) for 10 min at 80°C. Thereafter, both the pretreated solution and the residue were used as a reductant for manganese leaching. This method not only exhibited superior activity for hydrolyzing cornstalk but also enhanced manganese dissolution. These effects were attributed to an increase in the amount of reductive sugars resulting from lignin hydrolysis. Through acid pretreatment for cornstalk, the manganese dissolution ratio was improved from 50.14% to 83.46%. The present work demonstrates for the first time the effective acid pretreatment of cornstalk to provide a cost-effective reductant for manganese leaching.

  11. Assessment of heavy metals leaching from (biochar obtained from industrial sewage sludge

    Directory of Open Access Journals (Sweden)

    Julija Pečkytė

    2015-10-01

    Full Text Available Biochar can be produced from many various feedstock including biomass residues such as straw, branches, sawdust and other agricultural and forestry waste. One of the alternatives is to obtain biochar from industrial sewage sludge, however, the use of such a product could be limited due to high quantities of heavy metals in the biochar as a product. Total concentration of heavy metals provides only limited information on the behavior of heavy metals, therefore, batch leaching and up-flow percolation leaching tests were applied to study the leaching of heavy metals (Cd, Pb, Cr, Ni, Zn, Cu from (biochar produced from two types of sewage sludge: from paper mill and leather industries.

  12. A study on the recycling of scrap integrated circuits by leaching.

    Science.gov (United States)

    Lee, Ching-Hwa; Tang, Li-Wen; Popuri, Srinivasa R

    2011-07-01

    In order to minimize the problem of pollution and to conserve limited natural resources, a method to recover the valuable metals such as gold, silver and copper) present in the scrap integrated circuits (ICs) was developed in the present study. Roasting, grinding, screening, magnetic separation, melting and leaching were adopted to investigate the efficiency of recovery of gold, silver and copper from scrap ICs. The collected scrap IC samples were roasted at 850 °C to destroy their plastic resin sealing material, followed by screening and magnetic separation to separate the metals from the resin residue. The non-ferrous materials (0.840 mm) were mainly composed of copper and could be melted into a copper alloy. Non-ferrous materials containing gold (860.05 ppm), silver (1323.12 ppm) and copper (37259.7 ppm) (size less than 50 mesh) were recovered 100% by a leaching process and thiourea was used as a leaching reagent.

  13. Reductive leaching of low-grade manganese ore with pre-processed cornstalk

    Institute of Scientific and Technical Information of China (English)

    Ai-fei Yi; Meng-ni Wu; Peng-wei Liu; Ya-li Feng; Hao-ran Li

    2015-01-01

    Cornstalk is usually directly used as a reductant in reductive leaching manganese. However, low utilization of cornstalk makes low manganese dissolution ratio. In the research, pretreatment for cornstalk was proposed to improve manganese dissolution ratio. Cornstalk was preprocessed by a heated sulfuric acid solution (1.2 M of sulfuric acid concentration) for 10 min at 80°C. Thereafter, both the pretreated solu-tion and the residue were used as a reductant for manganese leaching. This method not only exhibited superior activity for hydrolyzing corn-stalk but also enhanced manganese dissolution. These effects were attributed to an increase in the amount of reductive sugars resulting from lignin hydrolysis. Through acid pretreatment for cornstalk, the manganese dissolution ratio was improved from 50.14%to 83.46%. The pre-sent work demonstrates for the first time the effective acid pretreatment of cornstalk to provide a cost-effective reductant for manganese leaching.

  14. ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

    Science.gov (United States)

    Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

    1957-11-12

    A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

  15. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    this study, a fly ash sample from an operating Danish power plant based on wood biomass was collected, chemically characterized and investigated for its leaching release of nutrients and heavy metals. A column leaching test was employed. The strongly alkaline pH of all the collected eluates suggested...... the potential suitability of the ash as a liming material. Although high contents of nutrients were detected, differences in their leaching release were found. Heavy metals were detected within typical literature contents for Nordic countries ashes....

  16. Leaching potential and changes in components of metals in two acidic ferrisols

    Institute of Scientific and Technical Information of China (English)

    GUO Zhao-hui; LIAO Bo-han; HUANG Chang-yong

    2006-01-01

    Two acidic ferrisols, i.e., red soil (RS) and yellow red soil (YRS), from the vicinity regions of non-ferrous ores in Hunan province of China, were leached with simulated acid rain through artificial column experiments. The results show that the total leaching mass of metals are m(Zn)>m(Cu)>m(Cd) from the original soils and m(Cd)>m(Zn)>> m(Cu) from the contaminated soils with external metals after leaching for 60 d continuously, leaching quantities of Cd and Zn from the contaminated red soil (CRS)are more than that from the contaminated yellow red soil (CYRS), but for Cu, it is almost the same. The preferential fractions for leaching are mainly in exchangeable forms, and content of exchangeable forms decreases significantly in the contaminated soil profiles. The unstable fractions of Cd, Cu and Zn in the RS and YRS increase significantly with the decrease of pH value of simulated acid rain. Changes of fractions of external Cd, Cu, and Zn in the residual CRS and CYRS profiles are significantly affected by the acidity of acid rain, too. After leaching for 60 d continuously, Cd exists mostly in exchangeable form, Cu exists mainly in exchangeable, manganese oxide-occluded and organically bounding forms, and Zn exists in residual in CRS and CYRS profiles.Most of exchangeable Cd and Zn exist only small in surface layer (0-20 cm) and are transferred to the sub-layers, contrarily, Cu accumulates mostly in the topsoil (0-20 cm) with low translocation.

  17. Watchdog-LEACH: A new method based on LEACH protocol to Secure Clustered Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Rohbanian

    2013-07-01

    Full Text Available Wireless sensor network comprises of small sensor nodes with limited resources. Clustered networks have been proposed in many researches to reduce the power consumption in sensor networks. LEACH is one of the most interested techniques that offer an efficient way to minimize the power consumption in sensor networks. However, due to the characteristics of restricted resources and operation in a hostile environment, WSNs are subjected to numerous threats and are vulnerable to attacks. This research proposes a solution that can be applied on LEACH to increase the level of security. In Watchdog-LEACH, some nodes are considered as watchdogs and some changes are applied on LEACH protocol for intrusion detection. Watchdog-LEACH is able to protect against a wide range of attacks and it provides security, energy efficiency and memory efficiency. The result of simulation shows that in comparison to LEACH, the energy overhead is about 2% so this method is practical and can be applied to WSNs.

  18. Factors influencing leaching of PBDEs from waste cathode ray tube plastic housings.

    Science.gov (United States)

    Stubbings, William A; Harrad, Stuart

    2016-11-01

    Samples of waste cathode ray tube (CRT) plastic housings were exposed to Milli-Q® water containing dissolved humic matter at concentrations of 0, 100 and 1000mgL(-1) as leaching fluid under laboratory conditions, and polybrominated diphenyl ethers (PBDEs) determined in the resulting leachate. Despite the relatively hydrophobic physicochemical properties of PBDEs, concentrations of ƩPBDEs in the leachate from the leaching experiments in this study ranged from 14,000 to 200,000ngL(-1). PBDE leaching appears to be a second order process, whereby a period of initially intense dissolution of more labile PBDEs is followed by a slower stage corresponding to external diffusion of the soluble residue in the material. The bulk of transfer of PBDEs to the leaching fluid occurs within the first 6h of contact, during which time we suggest that the most labile PBDEs are "washed" off the surface of the CRT plastics. The predominant congeners in the chips were BDE-209 (2600mgkg(-1)) and BDE 183 (220mgkg(-1)). The impacts on PBDE leaching of leachate pH and temperature were also examined. Increasing the temperature of leaching fluids from 20 to 80°C, enhances the leachability of BDE-209 and BDE-99 from plastics. In all cases, the alkaline pH8.5 examined, resulted in the greatest PBDE concentrations in leachate. Agitation of the waste/leachate mixture enhances PBDE leaching from CRT plastics. Potential evidence for debromination of heavy congeners to the lower brominated and more bioavailable BDEs was observed. Specifically, BDEs-47, -85 and -100 were detected in the leachates, but were absent from the CRT plastics themselves. PMID:27436776

  19. Residual Momentum

    NARCIS (Netherlands)

    D.C. Blitz (David); J.J. Huij (Joop); M.P.E. Martens (Martin)

    2011-01-01

    textabstractConventional momentum strategies exhibit substantial time-varying exposures to the Fama and French factors. We show that these exposures can be reduced by ranking stocks on residual stock returns instead of total returns. As a consequence, residual momentum earns risk-adjusted profits th

  20. Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process.

    Science.gov (United States)

    Swain, Basudev; Mishra, Chinmayee; Lee, Chan Gi; Park, Kyung-Soo; Lee, Kun-Jae

    2015-07-01

    Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga0.97N0.9O0.09 is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga0.97N0.9O0.09 of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4M HCl, 100°C and pulp density of 100 kg/m(3,) respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition.

  1. Comparision of Different Reductants in Leaching of Spent Lithium Ion Batteries

    Science.gov (United States)

    Meshram, Pratima; Abhilash; Pandey, Banshi Dhar; Mankhand, Tilak Raj; Deveci, Haci

    2016-10-01

    The present work focuses on the processing of cathode active material of spent lithium ion batteries to improve the recovery of constituent metals using reducing agents. Reductants enhance the solubility of metals, which hitherto have been solubilised to a lesser extent using only acid as leaching agent. Thus, we have investigated sulfuric acid leaching in the presence of sodium bisulfite comparing its efficiency with hydrogen peroxide. By simple acid leaching using 1 M H2SO4 at 368 K and 50 g/L pulp density, 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn were recovered in 240 min. In the presence of 5% H2O2 as a reducing agent at 368 K with 1 M H2SO4 and 50 g/L pulp density, the leaching of cobalt (79.2%) and manganese (84.6%) were significantly improved in 240 min. With the addition of 0.075 M NaHSO3 as a reducing agent, ~96.7% Li, 91.6% Co, 96.4% Ni and 87.9% Mn were recovered under similar conditions. Sodium bisulfite addition results in better recovery of cobalt and manganese by reducing them to their lower oxidation states. The HSC evaluation of thermodynamic feasibility vis-à-vis x-ray diffraction and scanning electron microscopy characterization of residues generated by leaching with hydrogen peroxide and sodium bisulfite substantiates the governing mechanism.

  2. Recovery of zinc and manganese from spent batteries by reductive leaching in acidic media

    Science.gov (United States)

    Buzatu, M.; Săceanu, S.; Petrescu, M. I.; Ghica, G. V.; Buzatu, T.

    2014-02-01

    A systematic investigation has been carried out on the influence of the acid leaching process parameters on the simultaneous metal recovery (Zn and Mn) from the electrode paste of spent alkaline Zn-MnO2 and spent Zn-C batteries. By introducing a reducing agent namely 30% H2O2 in the H2SO4 leaching solution the extraction efficiency for Mn was increased from 43.5% (no addition of H2O2) up to 97.54% (50% excess H2O2 in comparison with the required stoichiometric amount of H2O2). This H2O2 addition proved to have no influence on Zn extraction efficiency which kept constant at a high level (∼98.4%). A less important influence has been noticed for the molar concentration of H2SO4 in the leaching solution. In the range 0.5 M up to 2 M molar concentration of H2SO4 the extraction efficiency was increased from 78.2% up to 98.4% for Zn and from 63.1% up to 97.2% for Mn. Leaching time up to 60 min proved to gradually increase the extraction efficiency up to 96% for Mn and 98% for Zn but further time increase has no more influence. An attempt has been made to recover the carbon from the leaching residue but its structural characterization is still required.

  3. Effects of sewage sludge amendments on pesticide sorption and leaching through undisturbed Mediterranean soils.

    Science.gov (United States)

    Imache, Ahde El; Dousset, Sylvie; Satrallah, Ahmed; Dahchour, Abdelmalek

    2012-01-01

    The Gharb region in Morocco is an important agricultural zone where soils receive pesticide treatments and organic amendments to increase yields. The groundwater aquifer in the Gharb region is relatively shallow and thus vulnerable. The objective of this work was to study the influence of organic amendments on diuron, cyhalofop-butyl and procymidone leaching through undisturbed soil columns. Two soils were sampled from the Gharb region, a Dehs (sandy soil) and a R'mel (loamy clay soil). Following elution (124.5 mm), the amount of pesticide residues in the leachates of the sandy soil (0.06-0.21 %) was lower than in those of the loamy clay soil (0.20-0.36 %), which was probably due to preferential flow through the loamy clay soil. The amount of procymidone leached through the amended soil columns was greater than the control for the sandy soil only. The organic amendments did not significantly influence diuron and cyhalofop-butyl leaching in either of the soils. The application of organic amendments affected the amounts of dissolved organic matter (DOM) eluted and thus pesticide leaching as a function of soil-type. Nevertheless, in some case, the formation of pesticide-DOM complexes appeared to promote pesticide leaching, thus increasing groundwater contamination risks. PMID:22375587

  4. Comparision of Different Reductants in Leaching of Spent Lithium Ion Batteries

    Science.gov (United States)

    Meshram, Pratima; Abhilash; Pandey, Banshi Dhar; Mankhand, Tilak Raj; Deveci, Haci

    2016-07-01

    The present work focuses on the processing of cathode active material of spent lithium ion batteries to improve the recovery of constituent metals using reducing agents. Reductants enhance the solubility of metals, which hitherto have been solubilised to a lesser extent using only acid as leaching agent. Thus, we have investigated sulfuric acid leaching in the presence of sodium bisulfite comparing its efficiency with hydrogen peroxide. By simple acid leaching using 1 M H2SO4 at 368 K and 50 g/L pulp density, 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn were recovered in 240 min. In the presence of 5% H2O2 as a reducing agent at 368 K with 1 M H2SO4 and 50 g/L pulp density, the leaching of cobalt (79.2%) and manganese (84.6%) were significantly improved in 240 min. With the addition of 0.075 M NaHSO3 as a reducing agent, ~96.7% Li, 91.6% Co, 96.4% Ni and 87.9% Mn were recovered under similar conditions. Sodium bisulfite addition results in better recovery of cobalt and manganese by reducing them to their lower oxidation states. The HSC evaluation of thermodynamic feasibility vis-à-vis x-ray diffraction and scanning electron microscopy characterization of residues generated by leaching with hydrogen peroxide and sodium bisulfite substantiates the governing mechanism.

  5. Effect of Tetrachloroethylene on Sphalerite Leaching

    Institute of Scientific and Technical Information of China (English)

    王兴尧; 彭鹏; 谢慧琴; 卢立柱

    2004-01-01

    The effects of tetrachloroethylene (C2C14) on sphalerite leaching in FeCl3-HCl wereinvestigated in view of simultaneous mass transfer and reaction, and the leaching models with andwithout organic solvent C2Cl4 were derived. The leaching experiments and the SEM results show thatC2C14 is an effective organic solvent for sphalerite leaching in FeC13-HC1 system to be accelerated andfor the sulfur to be separated. Adding C2C14 in the FeCl3-HC1 medium will turn the kinetic modelcontrolled by sulfur layer diffusion with process activation energy of 67.9 kJ/mol into mixed diffusionwith the energy reduced to 55.1 kJ/mol when 20 ml of C2C14 was added.

  6. Alternative leaching processes for uranium ores

    International Nuclear Information System (INIS)

    Laboratory studies have been carried out to compare the extraction of uranium from Australian ores by conventional leaching in sulphuric acid with that obtained using hydrochloric acid and acidified ferric sulphate solutions. Leaching with hydrochloric acid achieved higher extractions of radium-226 but the extraction of uranium was reduced considerably. The use of acidified ferric sulphate solution reduced acid consumption by 20-40% without any detrimental effect on uranium extraction. The ferric ion, which is reduced during leaching, can be reoxidized and recycled after the addition of acid makeup. Hydrogen peroxide was found to be an effective oxidant in conventional sulphuric acid leaching. It is more expensive than alternative oxidants, but it is non-polluting, lesser quantities are required and acid consumption is reduced

  7. Removal of lead from cathode ray tube funnel glass by combined thermal treatment and leaching processes.

    Science.gov (United States)

    Okada, Takashi; Nishimura, Fumihiro; Yonezawa, Susumu

    2015-11-01

    The reduction melting process is useful to recover toxic lead from cathode ray tube funnel glass; however, this process generates SiO2-containing residues that are disposed in landfill sites. To reduce the volume of landfill waste, it is desirable to recycle the SiO2-containing residues. In this study, SiO2 powder was recovered from the residue generated by reduction melting. The funnel glass was treated by a process combining reduction melting at 1000°C and annealing at 700°C to recover a large quantity of lead from the glass. The oxide phase generated by the thermal treatment was subjected to water leaching and acid leaching with 1M hydrochloric acid to wash out unwanted non-SiO2 elements for SiO2 purification. In the water washing, the oxide phase was microparticulated, and porous structures formed on the oxide surfaces. This increased the surface area of the oxide phase, and the unwanted elements were effectively washed out during the subsequent acid leaching. By controlling the acid leaching time and the amount of added acid, porous and amorphous SiO2 (purity >95 wt%) was recovered. In the obtained SiO2-concentrated product, unrecovered lead remained at concentrations of 0.25-0.79 wt%. When the Na2CO3 dosage in the thermal treatment was increased, the lead removal by acid leaching was enhanced, and the lead concentration in the obtained product decreased to 0.016 wt%. PMID:26022339

  8. YACON INULIN LEACHING DURING HOT WATER BLANCHING

    OpenAIRE

    Caroline Fenner Scher; Adriano Brandelli; Caciano Zapata Noreña

    2015-01-01

    ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching un...

  9. Quantification of uncertainty of experimental measurement in leaching test on cement-based materials.

    Science.gov (United States)

    Coutand, M; Cyr, M; Clastres, P

    2011-10-01

    When mineral wastes are reused in construction materials, a current practice is to evaluate their environmental impact using standard leaching test. However, due to the uncertainty of the measurement, it is usually quite difficult to estimate the pollutant potential compared to other materials or threshold limits. The aim of this paper is to give a quantitative evaluation of the uncertainty of leachate concentrations of cement-based materials, as a function of the number of test performed. The relative standard deviations and relative confidence intervals are determined using experimental data in order to give a global evaluation of the uncertainty of leachate concentrations (determination of total relative standard deviation). Various combinations were realized in order to point out the origin of large dispersion of the results (determination of relative standard deviation linked to analytical measured and to leaching procedure), generalisation was suggested and the results were compared to literature. An actual example was given about the introduction of residue (meat and bone meal bottom ash--MBM-BA) in mortar, leaching tests were carried out on various samples with and without residue MBM-BA. In conclusion large dispersion were observed and mainly due to heterogeneity of materials. So heightened attention needed to analyse leaching result on cement-based materials and further more other tests (e.g. ecotoxicology) should be performed to evaluate the environmental effect of these materials.

  10. Heat transfer law in leaching dump

    Institute of Scientific and Technical Information of China (English)

    WU Ai-xiang; WANG Hong-jiang; XI Yong; YANG Bao-hua; LI Jian-feng; YIN Sheng-hua; ZHA Ke-bing

    2005-01-01

    Based on the law of temperature changes in the leaching dump and the forming process of heat flux, the basic balance equation of heat flow in dump was established, the dissipated heat flow from dump to the atmosphere was analyzed to estimate the surface temperature of the ore particle in dump and discover the law of forced heat convection of heat flow transfer in dump. And the lixiviate flow formula taking a certain heat flow out of dump was deduced by using the inversion method. Through theoretic analysis, combining Dexing copper mine heap leaching production practice, the results show that the heat flow of chalcopyrite leaching emitted is not so great, but the heat flow of pyrite leaching and sulphur oxidation produced take up a higher proportion of total heat flow; the dissipated heat flow takes up a lower proportion, and most of heat flow is absorbed by itself, thus the inside temperature rises gradually; and the saturation flow form for leaching is adopted, which makes the lixiviate seepage in the transitional flow or even in the turbulent flow, so as to accelerate the heat flow diffusing and keep the leaching dump temperature suitable for bacteria living.

  11. Treatment of cadmium dust with two-stage leaching process

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The treatment of cadmium dust with a two-stage leaching process was investigated to replace the existing sulphation roast-leaching processes. The process parameters in the first stage leaching were basically similar to the neutralleaching in zinc hydrometallurgy. The effects of process parameters in the second stage leaching on the extraction of zincand cadmium were mainly studied. The experimental results indicated that zinc and cadmium could be efficiently recoveredfrom the cadmium dust by two-stage leaching process. The extraction percentages of zinc and cadmium in two stage leach-ing reached 95% and 88% respectively under the optimum conditions. The total extraction percentage of Zn and Cdreached 94%.

  12. Zinc Leaching from Tire Crumb Rubber

    Science.gov (United States)

    Rhodes, E. P.; Ren, J.; Mays, D. C.

    2010-12-01

    Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

  13. Optimization of the factors that accelerate leaching

    International Nuclear Information System (INIS)

    The prediction of long-term leachability of low-level radioactive waste forms is an essential element of disposal-site performance assessment. This report describes experiments and modeling techniques used to develop an accelerated leach test that meets this need. The acceleration in leaching rates caused by the combinations of two or more factors were experimentally determined. These factors were identified earlier as being able to individually accelerate leaching. They are: elevated temperature, the size of the waste form, the ratio of the volume of leachant to the surface area of the waste form, and the frequency of replacement of the leachant. The solidification agents employed were ones that are currently used to treat low-level radioactive wastes, namely portland type I cement, bitumen, and vinyl ester-styrene. The simulated wastes, sodium sulfate, sodium tetraborate, and incinerator ash, are simplified representatives of typical low-level waste streams. Experiments determined the leaching behavior of the radionuclides of cesium (Cs-137), strontium (Sr-85), and cobalt (Co-60 or Co-57) from several different formulations of solidification agents and waste types. Leaching results were based upon radiochemical and elemental analyses of aliquots of the leachate, and on its total alkalinity and pH at various times during the experiment (up to 120 days). Solid phase analyses were carried out by Scanning/Electron Microscopy and Energy Dispersive Spectroscopy on the waste forms before and after some leaching experiments. 43 refs., 96 figs., 16 tabs

  14. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

    International Nuclear Information System (INIS)

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na2CO3, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na2CO3, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga2O3 and GaN to NaGaO2 revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved

  15. Influencing factors of pyrite leaching in germ-free system

    Institute of Scientific and Technical Information of China (English)

    OU Le-ming; HE Rong-quan; FENG Qi-ming

    2007-01-01

    The effect of mineral particle size,pulp potential and category of oxidant on pyrite leaching was studied.The results show that a smaller mineral particle size leads to a higher leaching rate of pyrite, and the optimum result with pyrite leaching rate of 2.92% is obtained when mineral particle size is less than 0.037 1/mm.The pulp potential reflects the leaching process. The increase of pulp potential can improve pyrite leaching. The leaching rate and velocity of pyrite can be enhanced rapidly by adding strong oxidant. The kind and the method of adding oxidant have important effect on the pyrite leaching. Appropriate concentration of Fe3+ can enhance pyrite leaching but the precipitation generated by high concentration of ferric ion covers the surface of pyrites and prevents the leaching process.The leaching rate increases with the constant addition of H2O2.

  16. Development of hydrometallurgical leaching liquor regeneration process by capture of CO2 from pyrometallurgical flue gas

    OpenAIRE

    Wylock, Christophe; Antunano, Nestor; Arias, Pedro Luis; Haut, Benoît

    2013-01-01

    The steelmaking industry that uses electric arc furnaces (EAF) generates as its main residue EAF dust, which must be treated to recycle Zn, Pb and other metals to prevent environmental impacts. Waelz process is the most common technology for this purpose, generating concentrates of Zn and Pb oxides (called Waelz oxides). One of their many applications is the Zn production in Imperial Smelting furnaces. This work deals with the development of a regeneration process of leaching liquors used in ...

  17. Environmental impact of APC residues from municipal solid waste incineration: reuse assessment based on soil and surface water protection criteria.

    Science.gov (United States)

    Quina, Margarida J; Bordado, João C M; Quinta-Ferreira, Rosa M

    2011-01-01

    Waste management and environmental protection are mandatory requirements of modern society. In our study, air pollution control (APC) residues from municipal solid waste incinerators (MSWI) were considered as a mixture of fly ash and fine particulate solids collected in scrubbers and fabric filters. These are hazardous wastes and require treatment before landfill. Although there are a number of treatment options, it is highly recommended to find practical applications rather than just dump them in landfill sites. In general, for using a construction material, beyond technical specifications also soil and surface water criteria may be used to ensure environmental protection. The Dutch Building Materials Decree (BMD) is a valuable tool in this respect and it was used to investigate which properties do not meet the threshold criteria so that APC residues can be further used as secondary building material. To this end, some scenarios were evaluated by considering release of inorganic species from unmoulded and moulded applications. The main conclusion is that the high amount of soluble salts makes the APC residues a building material prohibited in any of the conditions tested. In case of moulding materials, the limits of heavy metals are complied, and their use in Category 1 would be allowed. However, also in this case, the soluble salts lead to the classification of "building material not allowed". The treatments with phosphates or silicates are able to solve the problem of heavy metals, but difficulties with the soluble salts are still observed. This analysis suggests that for APC residues to comply with soil and surface water protection criteria to be further used as building material at least a pre-treating for removing soluble salts is absolutely required.

  18. Effect of improving flue gas cleaning on characteristics and immobilisation of APC residues from MSW incineration

    Energy Technology Data Exchange (ETDEWEB)

    Geysen, D. [Public Waste Agency of Flanders, OVAM, Stationsstraat 110, B-2800 Mechelen (Belgium)]. E-mail: daneel.geysen@ovam.be; Vandecasteele, C. [Department of Chemical Engineering, K.U. Leuven, de Croylaan 46, B-3001, Leuven (Belgium); Jaspers, M. [INDAVER, Dijle 17 a, B-2800 Mechelen (Belgium); Brouwers, E. [INDAVER, Dijle 17 a, B-2800 Mechelen (Belgium); Wauters, G. [INDAVER, Dijle 17 a, B-2800 Mechelen (Belgium)

    2006-01-16

    The flue gas cleaning system of a MSW incinerator with a capacity of 350 kt/year was changed to improve the HCl elimination efficiency. Instead of the semi-wet operating spray reactor and subsequent baghouse, a two-step wet flue gas cleaning was added behind the baghouse. Elemental composition, X-ray powder diffraction patterns and TGA measurements showed that the resulting APC residue was totally different from the former residue. As a consequence, leaching characteristics of both residues also differed and another treatment was required prior to disposal. For the former residue, mainly leaching of Pb (>100 mg/l), necessitated treatment prior to landfilling. The lower alkalinity of the new residue resulted in a leachate pH of 9.7 and a Pb concentration of 0.8 mg/l. The leachate pH of the former residue was 12.4. The leaching of Pb and Zn increased above 100 mg/l when immobilising the new residue with cement. Better results were obtained when immobilising with micro silica. The high CaCl{sub 2}.2H{sub 2}O content of the new residue brought along clogging of the bag filter system. Adding 1.4% of CaO (or 1.9% of Ca(OH){sub 2}) to the residue already improved these inconveniences but again significantly changed the leaching behaviour of the residue.

  19. 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

  20. Speciation of heavy metals in garden soils. Evidences from selective and sequential chemical leaching

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhongqi; Lee, Leda; Dayan, Sara; Grinshtein, Michael [Brooklyn College of The City Univ. of New York, Brooklyn, NY (United States). Environmental Sciences Analytical Cnter; Shaw, Richard [USDA-NRCS NYC Soil Survey, Staten Island, NY (United States)

    2011-06-15

    Purpose: Gardening (especially food growing) in urban areas is becoming popular, but urban soils are often very contaminated for historical reasons. There is lack of sufficient information as to the bioavailability of soil heavy metals to plants and human in urban environments. This study examines the relative leachability of Cr, Ni, As, Cd, Zn, and Pb for soils with varying characteristics. The speciation and mobility of these metals can be qualitatively inferred from the leaching experiments. The goal is to use the data to shed some light on their bioavailability to plant and human, as well as the basis for soil remediation. Materials and methods: Selective and sequential chemical leaching methods were both used to evaluate the speciation of Cr, Ni, As, Cd, Zn, and Pb in soil samples collected from New York City residential and community gardens. The sequential leaching experiment followed a standard BCR four-step procedure, while selective leaching involved seven different chemical extractants. Results and discussion: The results from selective and sequential leaching methods are consistent. In general, very little of the heavy metals were found in the easily soluble or exchangeable fractions. Larger fractions of Cd and Zn can be leached out than other metals. Lead appears predominantly in the organic or carbonate fractions, of which {proportional_to} 30-60% is in the easily soluble organic fraction. Most As cannot be leached out by any of the extractants used, but it could have been complicated by the ineffective dissolution of oxides by ammonium hydroxylamine. Ni and Cr were mostly in the residual fractions but some released in the oxidizable fractions. Therefore, the leachability of metals follow the order Cd/Zn > Pb > Ni/Cr. Conclusions: Despite of the controversy and inaccuracy surrounding chemical leaching methods for the speciation of metals, chemical leaching data provide important, general, and easy-to-access information on the mobility of heavy metals

  1. 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.

  2. Analysis of factors affecting the effect of stope leaching

    International Nuclear Information System (INIS)

    The industrial test and industrial trial production of stope leaching were carried out at Taoshan orefield of Dabu deposit. The results of test and trial production showed obvious differences in leaching rate and leaching time. Compared with industrial trial production of stope leaching, the leaching rate of industrial test was higher, and leaching time was shorter. It was considered that the blasting method and liquid arrangement were the main factors affecting the leaching rate and leaching time according to analysis. So we put forward the following suggestions: the technique of deep hole slicing tight-face blasting was used to reduce the yield of lump ores, the effective liquid arrangement methods were adopted to make the lixiviant infiltrating throughout whole ore heap, and bacterial leaching was introduced. (authors)

  3. Distribution and leaching of methyl iodide in soil following emulated shank and drip application.

    Science.gov (United States)

    Guo, Mingxin; Zheng, Wei; Papiernik, Sharon K; Yates, Scott R

    2004-01-01

    Methyl iodide (MeI) is a promising alternative to methyl bromide in soil fumigation. The pest-control efficacy and ground water contamination risks of MeI as a fumigant are highly related to its gas-phase distribution and leaching after soil application. In this study, the distribution and leaching of MeI in soil following shank injection and subsurface drip application were investigated. Methyl iodide (200 kg ha(-1)) was directly injected or drip-applied at a 20-cm depth into Arlington sandy loam (coarse-loamy, mixed, thermic Haplic Durixeralfs) columns (12-cm i.d., 70-cm height) tarped with virtually impermeable film. Concentration profiles of MeI in the soil air were monitored for 7 d. Methyl iodide diffused rapidly after soil application, and reached a 70-cm depth within 2 h. Relative to shank injection, drip application inhibited diffusion, resulting in significantly lower concentration profiles in the soil air. Seven days after MeI application, fumigated soil was uncapped, aerated for 7 d, and leached with water. Leaching of MeI was significant from the soil columns under both application methods, with concentrations of >10 mug L(-1) in the early leachate. The leaching was greater following shank injection than drip application, with an overall potential of 33 g ha(-1) for shank injection and 19 g ha(-1) for drip application. Persistent residues of MeI remaining in soils after leaching were 50 to 240 ng kg(-1), and the contents were slightly higher following shank injection than drip application. The results suggest that fumigation with MeI may pose a risk of ground water contamination in vulnerable areas. PMID:15537937

  4. Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process

    International Nuclear Information System (INIS)

    Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga0.97N0.9O0.09 is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga0.97N0.9O0.09 of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4 M HCl, 100 °C and pulp density of 100 kg/m3, respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition. - Highlights: • Waste MOCVD dust is treated through mechanochemical leaching. • GaN is hardly leached, and converted to NaGaO2 through ball milling and annealing. • Process for gallium recovery from waste MOCVD dust has been developed. • Thermal analysis and phase properties of GaN to Ga2O3 and GaN to NaGaO2 is revealed. • Solid-state chemistry involved in this process is reported

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

    Science.gov (United States)

    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.

  6. Arbuscular mycorrhizas reduce nitrogen loss via leaching.

    Directory of Open Access Journals (Sweden)

    Hamid R Asghari

    Full Text Available The capacity of mycorrhizal and non-mycorrhizal root systems to reduce nitrate (NO₃⁻ and ammonium (NH₄⁺ loss from soils via leaching was investigated in a microcosm-based study. A mycorrhiza defective tomato mutant and its mycorrhizal wildtype progenitor were used in this experiment in order to avoid the indirect effects of establishing non-mycorrhizal control treatments on soil nitrogen cycling and the wider soil biota. Mycorrhizal root systems dramatically reduced nitrate loss (almost 40 times less via leaching, compared to their non-mycorrhizal counterparts, following a pulse application of ammonium nitrate to experimental microcosms. The capacity of AM to reduce nutrient loss via leaching has received relatively little attention, but as demonstrated here, can be significant. Taken together, these data highlight the need to consider the potential benefits of AM beyond improvements in plant nutrition alone.

  7. Behavior of calcium silicate in leaching process

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 李小斌; 彭志宏; 周秋生

    2003-01-01

    Based on the thermodynamic calculation, the mole ratio of CaO to SiO2, temperature and A/S of bauxitehave a profound influence on the mole ratio of 2CaO @ SiO2 to CaO @ SiO2 in sinter. CaO @ SiO2 and β-2CaO @ SiO2appear stable in caustic solution but unstable in soda solution, and CaO @ SiO2 is more stable than β-2CaO @ SiO2 un-der the same leaching condition. Compared with the conventional sinter, the rate of alumina extraction of the newsinter is large and the secondary reaction is restricted in the leaching, which might be mainly due to the more contentof CaO @ SiO2 in sinter and better stability of CaO @ SiO2 in leaching.

  8. 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.

  9. Leaching of vanadium from stone coal with sulfuric acid

    Institute of Scientific and Technical Information of China (English)

    WANG Mingyu; XIAO Liansheng; LI Qinggang; WANG Xuewen; XIANG Xiaoyan

    2009-01-01

    The effects of roasting, mass ratio of H2SO4 to stone coal, leaching temperature, liquid-to-solid ratio, grinding fineness of stone coal, and two-stage counter-current leaching on the vanadium leaching ratio were studied. The results show that the vanadium leaching ratio of roasted stone coal through two-stage counter-current leaching can reach 65.1% at the mass ratio of H2SO4 to stone coal of 20%, leaching temperature for the production of vanadium from stone coal.

  10. Saltstone Oxidation Study: Leaching Method

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A.; Stefanko, D. B.; Burns, H. H.

    2013-02-24

    Cementitious waste forms can be designed to chemically stabilize selected contaminants, such as Tc{sup +7} and Cr{sup +6}, by chemically reduction to lower valance states, Tc{sup +4} and Cr{sup +3}, respectively, and precipitation of these species in alkaline media as low solubility solid phases. Data for oxidation of this type of cementitious waste form cured under field conditions as a function of time is required for predicting the performance of the waste form and disposal facility. The rate of oxidation (oxidation front advancement) is an important parameter for predicting performance because the solubilities of some radionuclide contaminants, e.g., technetium, are a function of the oxidation state. A non-radioactive experiment was designed for quantifying the oxidation front advancement using chromium, as an approximate redox-sensitive surrogate (Cr{sup +6} / Cr{sup +3}) for technetium (Tc{sup +7} / Tc{sup +4}). Nonradioactive cementitious waste forms were prepared in the laboratory and cured under both laboratory and ?field conditions.? Laboratory conditions were ambient temperature and sealed sample containers. Field conditions were approximated by curing samples in open containers which were placed inside a plastic container stored outdoors at SRS. The container had a lid and was instrumented with temperature and humidity probes. Subsamples as thin as 0.2 mm were taken as a function of distance from the exposed surface of the as-cast sample. The subsamples were leached and the leachates were analyzed for chromium, nitrate, nitrite and sodium. Nitrate, nitrite, and sodium concentrations were used to provide baseline data because these species are not chemically retained in the waste form matrix to any significant extent and are not redox sensitive. ?Effective? oxidation fronts for Cr were measured for samples containing 1000, 500 and 20 mg/kg Cr added as soluble sodium chromate, Na{sub 2}CrO{sub 4}. For a sample cured for 129 days under field conditions

  11. Metallic elements fractionation in municipal solid waste incineration residues

    Science.gov (United States)

    Kowalski, Piotr R.; Kasina, Monika; Michalik, Marek

    2016-04-01

    Municipal solid waste incineration (MSWI) residues are represented by three main materials: bottom ash, fly ash and air pollution control (APC) residues. Among them ˜80 wt% is bottom ash. All of that materials are products of high temperature (>1000° C) treatment of waste. Incineration process allows to obtain significant reduction of waste mass (up to 70%) and volume (up to 90%) what is commonly used in waste management to reduce the amount need to be landfilled or managed in other way. Incineration promote accumulation non-combustible fraction of waste, which part are metallic elements. That type of concentration is object of concerns about the incineration residues impact on the environment and also gives the possibility of attempts to recover them. Metallic elements are not equally distributed among the materials. Several factors influence the process: melting points, volatility and place and forms of metallic occurrence in the incinerated waste. To investigate metallic elements distribution in MSWI residues samples from one of the biggest MSW incineration plant in Poland were collected in 2015. Chemical analysis with emphasis on the metallic elements content were performed using inductively coupled plasma optical emission (ICP-OES) and mass spectrometry (ICP-MS). The bottom ash was a SiO2-CaO-Al2O3-Fe2O3-Na2O rich material, whereas fly ash and APC residues were mostly composed of CaO and SiO2. All of the materials were rich in amorphous phase occurring together with various, mostly silicate crystalline phases. In a mass of bottom ash 11 wt% were metallic elements but also in ashes 8.5 wt% (fly ash) and ˜4.5 wt% (APC residues) of them were present. Among the metallic elements equal distribution between bottom and fly ash was observed for Al (˜3.85 wt%), Mn (770 ppm) and Ni (˜65 ppm). In bottom ash Fe (5.5 wt%), Cr (590 ppm) and Cu (1250 ppm) were concentrated. These values in comparison to fly ash were 5-fold higher for Fe, 3-fold for Cu and 1.5-fold for

  12. Air pollution control using particle filtration. 1964-November 1980 (citations from the NTIS Data Base). Report for 1964-November 1980

    Energy Technology Data Exchange (ETDEWEB)

    Cavagnaro, D.M.

    1980-12-01

    The citations discuss technology, equipment design and performance, ultrafiltration, and size distribution factors. Aerosol and dust filtration are included. Studies on electrostatic precipitators have been excluded. (This updated bibliography contains 229 citations, 56 of which are new entries to the previous edition.)

  13. An ex post cost-benefit analysis of the nitrogen dioxide air pollution control program in Tokyo

    Energy Technology Data Exchange (ETDEWEB)

    Voorhees, A.S.; Araki, S.; Sakai, R.; Sato, H. [University of Tokyo, Tokyo (Japan). Dept. of Public Health and Occupational Medicine

    2000-03-01

    The benefits and costs of past nitrogen dioxide (NO{sub 2}) control policies were calculated for Tokyo, Japan, using environmental, economic, political, demographic, and medical data from 1973 to 1994. The benefits of NO{sub 2} control were estimated as medical expenses and lost work time due to hypothetical no-control air concentrations of NO{sub 2}. Direct costs were calculated as annualized capital expenditures and 1 year's operating costs for regulated industries plus governmental agency expense. 46 refs., 8 figs., 6 tabs.

  14. Current analyses of problems of energy supply and air pollution control; Aktuelle Analysen zu energie- und klimapolitischen Fragen

    Energy Technology Data Exchange (ETDEWEB)

    Semrau, G. [Gesamtverbandes des deutschen Steinkohlenbergbaus, Essen (Germany)

    2001-10-11

    In an analysis of the electricity crisis in California the German Institute for Economic Research investigated the question whether similar problems could also arise in Europe. The outcome is that as a result of the liberalisation of the electricity markets in Europe the risk of temporary interruptions of supply tends to be greater and provision against contingencies is therefore advisable - in Great Britain intensive tests are currently being conducted on introduction of an emission trade system. In a recent analysis' Professor Luebbe-Wolff examined the British model and compared it with the German climate protection agreement. She concluded that there is no reason to advocate the British model and thus imply that the policy pursued hitherto in Germany is wrong. (orig.) [German] Das Deutsche Institut fuer Wirtschaftsforschung hat in einer Analyse der Stromkrise in Kalifornien die Frage untersucht, ob auch in Europa aehnliche Probleme entstehen koennten. Das Ergebnis ist, dass infolge der Liberalisierung der Strommaerkte in Europa das Risiko temporaerer Versorgungsstoerungen ohne flankierende Massnahmen eher groesser wuerde und daher Risikovorsorge geboten sei. - In Grossbritannien wird zur Zeit die Einfuehrung eines Emissionshandelssystems intensiv geprueft. In einer kuerzlich vorgelegten Analyse hat Frau Professor Luebbe-Wolff das britische Modell analysiert und der deutschen Klimaschutzvereinbarung gegenuebergestellt. Ihr Fazit: Es gibt keinen Grund, dem britischen Modell nachzueifern und damit implizit die in Deutschland bisher verfolgte Politik fuer verfehlt zu erklaeren. (orig.)

  15. Environmental health research in the UK and European Union : research priorities in water and air pollution control

    International Nuclear Information System (INIS)

    The contents are involvement of the European community, integration of research and development programmes ; surface water quality and pollution incidents; surface water pollution in the UK ; eutrophication ; drinking water quality ; causes and current treatment for removal of pollutants ; future causes of water pollution ; and , water and wastewater research

  16. A Model of Emission Trading for Minimizing the Cost of Air Pollution Control from Belgian Power Plants

    OpenAIRE

    Hecq, Walter; Kestemont, Bruno

    1991-01-01

    In Belgium recent national and community legislation regulates emission levels of "acid pollutants" (SO2, NOx) and apply to large combustion facilities whose pollutants are transported over large distances. Complying with these legislations requires costly emission control equipment. In order to minimize the costs of clean-up operations, this paper analyses the potentialities of an emission trading programme by means of a linear programming model. Six retrofit power plants have been chosen to...

  17. Air pollution control. Apparatus for quality control of immission measurements (AQIM). Luftueberwachung. Anlage zur Qualitaetssicherung von Immissionsmessungen (AQIM)

    Energy Technology Data Exchange (ETDEWEB)

    Manns, H.; Gies, H.; Nitz, H.

    1982-12-01

    Interlaboratory tests and comparative measurements are well suited to improve the state of knowledge and skill in connection with the analytical-chemical measurement methods for the purpose of maintaining quality of ambient air measurements by improving dependability and comparability of measuring procedures. For the execution of interlaboratory tests and comparative measurements with ambient-air measuring procedures (immission measurements) a sample air manifold has been developed, which can furnish about 30 participants simultaneously with a measuring gas. This apparatus has served with good success for comparative measurements on a national as well as international scale with procedures for benzene, toluene, xylene, vinyl chloride, nitrogen monoxide, nitrogen dioxide, and sulfur dioxide. Sampling of aromatic hydrocarbons by sorption on Tenax GC with the temperature gradient tube method has been investigated and process conditions to avoid decay of Tenax GC were improved. Suggestions for a simplified modification of aromatics sampling on Tenax GC are presented.

  18. A paradox for air pollution controlling in China revealed by “APEC Blue” and “Parade Blue”

    Science.gov (United States)

    Liu, Haoran; Liu, Cheng; Xie, Zhouqing; Li, Ying; Huang, Xin; Wang, Shanshan; Xu, Jin; Xie, Pinhua

    2016-09-01

    A series of strict emission control measures were implemented in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit and 2015 Grand Military Parade (Parade), which led to blue sky days during these two events commonly referred to as “APEC Blue” and “Parade Blue”. Here we calculated Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and Ozone Monitoring Instrument (OMI) NO2 and HCHO results based on well known DOAS trace gas fitting algorithm and WRF-Chem model (with measured climatology parameter and newest emission inventor) simulated trace gases profiles. We found the NO2 columns abruptly decreased both Parade (43%) and APEC (21%) compared with the periods before these two events. The back-trajectory cluster analysis and the potential source contribution function (PSCF) proved regional transport from southern peripheral cities plays a key role in pollutants observed at Beijing. The diminishing transport contribution from southern air mass during Parade manifests the real effect of emission control measures on NO2 pollution. Based on the ratios of HCHO over NO2 we found there were not only limited the NO2 pollutant but also suppress the O3 contaminant during Parade, while O3 increased during the APEC.

  19. Microwave-Mediated Green Synthesis of Silver Nanoparticles Using Ficus Elastica Leaf Extract and Application in Air Pollution Controlling Studies

    Directory of Open Access Journals (Sweden)

    N. Gandhi,

    2014-01-01

    Full Text Available Silver Nanoparticles are applied in various fields due to its anti bacterial properties. A conventional method for synthesis of AgNP requires dangerous chemical and large amount of energy is released in the process. Environmental friendly techniques are adopted for the synthesis of nanoparticles of silver. The present research work summarizes the green synthesis of silver nanoparticles by using leaf extract of Ficus Elastica and alternative energy sources micro wave irradiation. The synthesized Nanoparticles are characterized by uv- visible spectroscopy and by SEM. The synthesized nanoparticles are applied for controlling SO2 and NO2 from aqueous solution of SO2 and NO2. Batch adsorption studies are carried out. The effect of the temperature on adsorption of aqueous solution is studied at different temperature. A comparison of kinetic models applied to the adsorption of on silver Nanoparticles was evaluated for the pseudo first order, pseudo second order, Elovich and intraparticle diffusion models respectively. Results show that pseudo second order model was found to correlate the experimental data. Data fitted perfectly into and Freundlich adsorption isotherms.

  20. A paradox for air pollution controlling in China revealed by “APEC Blue” and “Parade Blue”

    Science.gov (United States)

    Liu, Haoran; Liu, Cheng; Xie, Zhouqing; Li, Ying; Huang, Xin; Wang, Shanshan; Xu, Jin; Xie, Pinhua

    2016-01-01

    A series of strict emission control measures were implemented in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit and 2015 Grand Military Parade (Parade), which led to blue sky days during these two events commonly referred to as “APEC Blue” and “Parade Blue”. Here we calculated Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and Ozone Monitoring Instrument (OMI) NO2 and HCHO results based on well known DOAS trace gas fitting algorithm and WRF-Chem model (with measured climatology parameter and newest emission inventor) simulated trace gases profiles. We found the NO2 columns abruptly decreased both Parade (43%) and APEC (21%) compared with the periods before these two events. The back-trajectory cluster analysis and the potential source contribution function (PSCF) proved regional transport from southern peripheral cities plays a key role in pollutants observed at Beijing. The diminishing transport contribution from southern air mass during Parade manifests the real effect of emission control measures on NO2 pollution. Based on the ratios of HCHO over NO2 we found there were not only limited the NO2 pollutant but also suppress the O3 contaminant during Parade, while O3 increased during the APEC. PMID:27680499

  1. Impact of air pollution control measures and weather conditions on asthma during the 2008 Summer Olympic Games in Beijing

    Science.gov (United States)

    Li, Yi; Wang, Wen; Wang, Jizhi; Zhang, Xiaoling; Lin, Weili; Yang, Yuanqin

    2011-07-01

    The alternative transportation strategy implemented during the 2008 Summer Olympic Games in Beijing provided an opportunity to study the impact of the control measures and weather conditions on air quality and asthma morbidity. An ecological study compared the 41 days of the Olympic Games (8 August-17 September 2008) to a baseline period (1-30 June). Also, in order to emphasize the impact of weather conditions on air quality, a pollution linking meteorological index (Plam) was introduced to represent the air pollution meteorological condition. Our study showed that the average number of outpatient visits for asthma was 12.5 per day at baseline and 7.3 per day during the Olympics—a 41.6% overall decrease. Compared with the baseline, the Games were associated with a significant reduction in asthma visits (RR 0.58, 95%CI: 0.52-0.65). At 16.5 visits per day, asthma visits were also significantly higher, during the pre-Olympic period (RR 1.32, 95% CI: 1.15-1.52). The study also showed that the RR of asthma events on a given day, as well as the average daily peak ozone concentration during the preceding 48-72 h, increased at cumulative ozone concentrations of 70 to 100 ppb and 100 ppb or more compared with ozone concentrations of less than 70 ppb ( P Olympic Games were associated with a prolonged reduction in air pollution and significantly lower rates of adult asthma events. These data provide support for efforts to reduce air pollution and improve health via reductions in motor vehicle traffic.

  2. 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.

  3. Prediction of leaching rate in heap leaching process by grey dynamic model GDM(1,1)

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-zhi; wu Ai-xiang

    2008-01-01

    The method of developing GM(1,1)model is extended on the basis of grey system theory.Conditions for the transfer function that improve smoothness of original data sequence and decrease the revert error are given.The grey dynamic model is first combined with the transfer function to predict the leaching rate in heap leaching process.The resuhs show that high prediction accuracy call be expected by using the proposed method.This provides a new approach to realize prediction and control of the future behavior of leaching kinetics.

  4. The leaching of base minerals from the calcines produced by the roasting of pyrite concentrates

    International Nuclear Information System (INIS)

    A number of gold and uranium plants in South Africa concentrate the pyrite in the ore residue by flotation and roast the concentrate for the production of sulphuric acid. The calcine produced, which is predominantly hematite, is generally subjected to cyanidation for the recovery of gold and silver. The calcines often contain economically significant quantities of copper, nickel , cobalt and uranium. Prior treatment of the calcine for the recovery of these metals would be desirable in terms of the value of the products. Several processes for the leaching of the base metals from plant calcines have been investigated, and an important general conclusion is that an adequate recovery of the base metals requires that a large proportion of the iron should also be extracted. This observation led to a more extensive investigation of the kinetics of leaching of various iron oxides. The application of electrochemical theory and techniques resulted in a fuller understanding of the various factors that govern the rate of leaching of iron oxides. As a result of this fundamental work, alternative treatment schemes that should yield more efficient extraction from calcines were suggested. Several of these possibilities were investigated, and the most promising were found to require reducing conditions during the leach, or prior partial reduction of the calcine to magnetite or wustite

  5. Risk of Leaching in Soils Amended by Compost and Digestate from Municipal Solid Waste

    Directory of Open Access Journals (Sweden)

    Marta García-Albacete

    2014-01-01

    Full Text Available New European directives have proposed the direct application of compost and digestate produced from municipal solid wastes as organic matter sources in agricultural soils. Therefore information about phosphorus leaching from these residues when they are applied to the soil is increasingly important. Leaching experiments were conducted to determine the P mobility in compost and digestate mixtures, supplying equivalent amounts to 100 kg P ha−1 to three different types of soils. The tests were performed in accordance with CEN/TS 14405:2004 analyzing the maximum dissolved reactive P and the kinetic rate in the leachate. P biowaste fractionation indicated that digestate has a higher level of available P than compost has. In contrast, P losses in leaching experiments with soil-compost mixtures were higher than in soil-digestate mixtures. For both wastes, there was no correlation between dissolved reactive P lost and the water soluble P. The interaction between soil and biowaste, the long experimentation time, and the volume of leachate obtained caused the waste’s wettability to become an influential parameter in P leaching behavior. The overall conclusion is that kinetic data analysis provides valuable information concerning the sorption mechanism that can be used for predicting the large-scale behavior of soil systems.

  6. Microwave treatment of electric arc furnace dust with PVC: dielectric characterization and pyrolysis-leaching.

    Science.gov (United States)

    Al-Harahsheh, Mohammad; Kingman, Sam; Al-Makhadmah, Leema; Hamilton, Ian E

    2014-06-15

    Microwave treatment of electric arc furnace dust (EAFD) with poly(vinyl chloride) (PVC) was studied in this work. A comprehensive characterization of the dust as well as assessing the suitability of using the thermal de-chlorination of the common plastic (PVC) under inert atmosphere was carried out to assess the possibility of Zn and other heavy metals extraction (Pb and Cd) from EAFD. The dielectric and thermal properties of EAFD, PVC and their mixtures were measured. Once combined and heated the metal oxides present in the dust reacted with HCl released from PVC during thermal de-chlorination, forming metal chlorides which were subsequently recovered by leaching with water. It was found that zinc chloride could be almost completely recovered in the leaching stage, with the overall recovery of Zn reaching 97% when the EAFD:PVC ratio was 1:2. The investigation highlighted that franklinite, the most refractory mineral to leaching, was completely destroyed. The leaching residue was found to compose mainly of magnetite and hematite.

  7. Microwave treatment of electric arc furnace dust with PVC: dielectric characterization and pyrolysis-leaching.

    Science.gov (United States)

    Al-Harahsheh, Mohammad; Kingman, Sam; Al-Makhadmah, Leema; Hamilton, Ian E

    2014-06-15

    Microwave treatment of electric arc furnace dust (EAFD) with poly(vinyl chloride) (PVC) was studied in this work. A comprehensive characterization of the dust as well as assessing the suitability of using the thermal de-chlorination of the common plastic (PVC) under inert atmosphere was carried out to assess the possibility of Zn and other heavy metals extraction (Pb and Cd) from EAFD. The dielectric and thermal properties of EAFD, PVC and their mixtures were measured. Once combined and heated the metal oxides present in the dust reacted with HCl released from PVC during thermal de-chlorination, forming metal chlorides which were subsequently recovered by leaching with water. It was found that zinc chloride could be almost completely recovered in the leaching stage, with the overall recovery of Zn reaching 97% when the EAFD:PVC ratio was 1:2. The investigation highlighted that franklinite, the most refractory mineral to leaching, was completely destroyed. The leaching residue was found to compose mainly of magnetite and hematite. PMID:24769846

  8. Leaching behavior of chromium in chrome shaving generated in tanning process and its stabilization.

    Science.gov (United States)

    Erdem, Mehmet; Ozverdi, Arzu

    2008-08-15

    In this study, leaching properties and pollution potential of chromium in chrome shaving (CS), which is a solid residue of leather industry, containing 2.27% Cr were investigated and thermal stabilization procedure was applied to the CS for chromium immobilization. For this purpose, firstly, effects of the liquid/solid ratio, contact time, pH and sequential extraction on the leaching behavior of chromium in the CS were studied. It was determined that the CS-caused chromium pollution is a hazardous material for environment. Thermal stabilization procedure was applied to the CS in the temperature range of 250-500 degrees C for the chromium immobilization. Effective stabilization of chromium in the CS was achieved by heating of CS at 350 degrees C under CO(2) atmosphere. Leaching experiments were also carried out with the samples obtained from the stabilization process and the results compared with that of the CS. Also, TCLP test method was applied to the samples to determine pollution potentials and discharge situations of the CS and its stabilization products. While the chromium concentrations in the test solutions of all samples stabilized thermally at above 350 degrees C were below the USEPA regulatory limit of 5 mg/l, the concentration of chromium leached out from the CS was 30-fold bigger than the USEPA regulatory limit.

  9. Spent LWR fuel leach tests: Waste Isolation Safety Assessment program

    International Nuclear Information System (INIS)

    Spent light-water-reactor (LWR) fuels with burnups of 54.5, 28 and 9 MWd/kgU were leach-tested in deionized water at 250C. Fuel burnup has no apparent effect on the calculated leach rates based upon the behavior of 137Cs and 239+240Pu. A leach test of 54.5 MWd/kgU spent fuel in synthetic sea brine showed that the cesium-based leach rate is lower in sea brine than in deionized water. A rise in the leach rate was observed after approximately 600 d of cumulative leaching. During the rise, the leach rate for all the measured radionuclides become nearly equal. Evidence suggests that exposure of new surfaces to the leachant may cause the increase. As a result, experimental work to study leaching mechanisms of spent fuel has been initiated. 22 figures

  10. Leaching of Main Elements of Glass Immersed in Beishan Groundwater

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The leaching quantities of the elements from the HLW are very important parameters for the safety assessments of the repository of high level radioactive wastes. It is necessary to study the leaching

  11. 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 Areni

  12. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  13. Mineralogy and uranium leaching of ores from Triassic Peribaltic sandstones

    OpenAIRE

    Gajda, Dorota; Kiegiel, Katarzyna; Zakrzewska-Koltuniewicz, Grazyna; Chajduk, Ewelina; Bartosiewicz, Iwona; Wolkowicz, Stanislaw

    2014-01-01

    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 so...

  14. Enhancements of LEACH Algorithm for Wireless Networks: A Review

    Directory of Open Access Journals (Sweden)

    M. Madheswaran

    2013-12-01

    Full Text Available Low Energy Adaptive Clustering Hierarchy (LEACH protocol is the first hierarchical cluster based routing protocol successfully used in the Wireless Sensor Networks (WSN. In this paper, various enhancements used in the original LEACH protocol are examined. The basic operations, advantages and limitations of the modified LEACH algorithms are compared to identify the research issues to be solved and to give the suggestions for the future proposed routing algorithms of wireless networks based on LEACH routing algorithm.

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

    OpenAIRE

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

    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...

  16. Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

    Science.gov (United States)

    Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

    2015-06-01

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. PMID:25771345

  17. The characterization of insoluble dissolver residues and the development of treatment methods

    International Nuclear Information System (INIS)

    Characterization studies have been carried out on the insoluble residue arising from laboratory scale dissolution of single pins of mixed oxide fuel irradiated in the Dounreay Fast Reactor (DFR). Similar characterization work has also been completed on six samples of insoluble residue recovered from the reprocessing of complete sub-assemblies of mixed oxide fuel irradiated in PFR. Treatment methods for the dissolver insolubles have consisted of preparing immobilized samples in sand/ordinary portland cement (OPC), sand/pulverized fly ash (PFA)/OPC, and blast furnace slag (BFS)/OPC. A programme of leach testing has been carried out according to the conditions laid down in the international Standard Organization Test. Four samples of DFR originated insoluble residues and six samples of PFR originated insoluble residues have been immobilized and leach tested. Variations have included experiments to evaluate the leach rate under temperature influence and to acid wash prior to immobilization

  18. Dual-functional Polyurea Microcapsules for Chronic Wound Care Dressings: Sustained Drug Delivery and Non-leaching Infection Control

    Science.gov (United States)

    He, Wei

    A new design of dual-functional polyurea microcapsules was proposed for chronic wound dressings to provide both non-leaching infection control and sustained topical drug delivery functionalities. Quaternary ammonium functionalized polyurea microcapsules (MCQs) were synthesized under mild conditions through an interfacial crosslinking reaction between branched polyethylenimine (PEI) and 2,4-toluene diisocyanate (TDI) in a dimethylformamide/cyclohexane emulsion. An in-situ modification method was developed to endow non-leaching surface antimicrobial properties to MCQs via bonding antimicrobial surfactants to surface isocyanate residues on the polyurea shells. The resultant robust MCQs with both non-leaching antimicrobial properties and sustained drug releasing properties have potential applications in medical textiles, such as chronic wound dressings, for infection control and drug delivery.

  19. Leaching of metals from steel samples in peracetic acid

    Science.gov (United States)

    Yabutani, Tomoki; Nakamura, Takamasa; Takayabagi, Toshio

    2015-03-01

    In this paper, leaching behavior of metallic species from steel samples in peracetic acid was investigated. We compared the leaching efficiency between peracetic acid and acetic acid to estimate the role of peroxo functional group for the leaching. As a result, peracetic acid enhanced the leaching ability of metallic species from the high speed steel and the alloy steel samples. MoO3, Mo, MO2C, W, WO3, VC and MnO2 were effectively leached by peracetic acid, while the stainless steel had a high resistance against corrosion by peracetic acid.

  20. Hot chlorine leaching techniques for determining failed-particle fraction in HTGR fuel compacts

    International Nuclear Information System (INIS)

    The high-temperature chlorine leaching techniques as nondestractive inspection of the failed-particle fraction in HTGR fuel compacts have been studied. Compacts containing bare UO2 kernels were leached with chlorine gas at temperatures from 7000 to 12000C by two methods. The static method using a closed quartz reaction vessel completely extracted the uranium, but it was difficult to purge the compact completely of chlorine. The flow method wherein chlorination was made in the gas stream within a glassy carbon tube had no problem of the residual chlorine. The static method simpler in operation is suitable for the post-irradiation experiment, and the flow method for the pre-irradiation inspection. (author)

  1. Washing and Caustic Leaching of Hanford Tank Sludge: Results of FY 1998 Studies

    Energy Technology Data Exchange (ETDEWEB)

    GJ Lumetta; BM Rapko; J Liu; DJ Temer; RD Hunt

    1998-12-11

    Sludge washing and parametric caustic leaching tests were performed on sludge samples tiom five Hanford tanks: B-101, BX-1 10, BX-112, C-102, and S-101. These studies examined the effects of both dilute hydroxide washing and caustic leaching on the composition of the residual sludge solids. ` Dilute hydroxide washing removed from <1 to 25% of the Al, -20 to 45% of the Cr, -25 to 97% of the P, and 63 to 99% of the Na from the Hdord tank sludge samples examined. The partial removal of these elements was likely due to the presence of water-soluble sodium salts of aluminate, chromate, hydroxide, nitrate, nitrite, and phosphate, either in the interstitial liquid or as dried salts.

  2. Water leaching of high and ultra high performance concrete: a nuclear magnetic resonance study

    Energy Technology Data Exchange (ETDEWEB)

    Porteneuve, Ch.; Zanni, H. [Ecole Superieure de Physique et Chimie Industrielles, Lab. de Physique et Mecanique des Milieux Heterogenes, UMR 7636, 75 - Paris (France); Korb, J.P.; Petit, D. [Ecole Polytechnique, Lab. de Physique de la Matiere Condenses, UMR 7643 du CNRS, 91 - Palaiseau (France)

    2001-11-01

    The consequences in terms of microstructure and texture of a prolonged contact between concrete and a continuous flow of mineral water have been investigated here by Nuclear Magnetic Resonance (NMR) because of its non-invasiveness and sensitivity to local environment. In particular, we evidence the dissolution of residual anhydrous cement, which leads to the further precipitation of hydrates occurring over 12 months of leaching tests in High Performance Concrete (HPC) and Ultra High Performance Concrete (UHPC). The study of the longitudinal relaxation of proton magnetization shows that the difference of pore size distribution between these two types of concrete remains mostly in the number of capillary pores. Its evolution with the time of water leaching up to the end of our experiment is not significant. (authors)

  3. Fertilizer management effects on nitrate leaching and indirect nitrous oxide emissions in irrigated potato production.

    Science.gov (United States)

    Venterea, Rodney T; Hyatt, Charles R; Rosen, Carl J

    2011-01-01

    Potato ( L.) is a N-intensive crop, with high potential for nitrate (NO) leaching, which can contribute to both water contamination and indirect nitrous oxide (NO) emissions. Two approaches that have been considered for reducing N losses include conventional split application (CSA) of soluble fertilizers and single application of polymer-coated urea (PCU). The objectives of this study were to: (i) compare NO leaching using CSA and two PCUs (PCU-1 and PCU-2), which differed in their polymer formulations, and (ii) use measured NO leaching rates and published emissions factors to estimate indirect NO emissions. Averaged over three growing seasons (2007-2009), NO leaching rates were not significantly different among the three fertilizer treatments. Using previously reported direct NO emissions data from the same experiment, total direct plus indirect growing season NO emissions with PCU-1 were estimated to be 30 to 40% less than with CSA. However, PCU-1 also resulted in greater residual soil N after harvest in 2007 and greater soil-water NO in the spring following the 2008 growing season. These results provide evidence that single PCU applications for irrigated potato production do not increase growing season NO leaching compared with multiple split applications of soluble fertilizers, but have the potential to increase N losses after the growing season and into the following year. Estimates of indirect NO emissions ranged from 0.8 to 64% of direct emissions, depending on what value was assumed for the emission factor describing off-site conversion of NO to NO. Thus, our results also demonstrate how more robust models are needed to account for off-site conversion of NO to NO, since current emission factor models have an enormous degree of uncertainty.

  4. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds.

    Science.gov (United States)

    Gale, Nigel V; Sackett, Tara E; Thomas, Sean C

    2016-01-01

    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-specific patterns of plant

  5. Fertilizer management effects on nitrate leaching and indirect nitrous oxide emissions in irrigated potato production.

    Science.gov (United States)

    Venterea, Rodney T; Hyatt, Charles R; Rosen, Carl J

    2011-01-01

    Potato ( L.) is a N-intensive crop, with high potential for nitrate (NO) leaching, which can contribute to both water contamination and indirect nitrous oxide (NO) emissions. Two approaches that have been considered for reducing N losses include conventional split application (CSA) of soluble fertilizers and single application of polymer-coated urea (PCU). The objectives of this study were to: (i) compare NO leaching using CSA and two PCUs (PCU-1 and PCU-2), which differed in their polymer formulations, and (ii) use measured NO leaching rates and published emissions factors to estimate indirect NO emissions. Averaged over three growing seasons (2007-2009), NO leaching rates were not significantly different among the three fertilizer treatments. Using previously reported direct NO emissions data from the same experiment, total direct plus indirect growing season NO emissions with PCU-1 were estimated to be 30 to 40% less than with CSA. However, PCU-1 also resulted in greater residual soil N after harvest in 2007 and greater soil-water NO in the spring following the 2008 growing season. These results provide evidence that single PCU applications for irrigated potato production do not increase growing season NO leaching compared with multiple split applications of soluble fertilizers, but have the potential to increase N losses after the growing season and into the following year. Estimates of indirect NO emissions ranged from 0.8 to 64% of direct emissions, depending on what value was assumed for the emission factor describing off-site conversion of NO to NO. Thus, our results also demonstrate how more robust models are needed to account for off-site conversion of NO to NO, since current emission factor models have an enormous degree of uncertainty. PMID:21712579

  6. Kinetic study on pressure leaching of high iron sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    XIE Ke-qiang; YANG Xian-wan; WANG Ji-kun; YAN Jiang-feng; SHEN Qing-feng

    2007-01-01

    The kinetics of pressure leaching high iron sphalerite concentrate was studied. The effects of agitation rate, temperature, oxygen partial pressure, initial acid concentration, particle size, iron content in the concentrate and concentration of Fe2+ added into the solution on the leaching rate of zinc were examined. The experiment results indicate that if the agitation rate is greater than 600 r/min, its influence on Zn leaching rate is not substantial. A suitable rise in temperature can facilitate the leaching reaction, and the temperature should be controlled at 140-150 ℃. The increase trend of Zn leaching rate becomes slow when pressure is greater than 1.2 MPa, so the pressure is controlled at 1.2-1.4 MPa. Under the conditions of this study, Zn leaching rate decreases with a rise in the initial sulfuric acid concentration; and Zn leaching rate increases with a rise of iron content in the concentrate and Fe2+ concentration in the solution. Moreover, the experiment demonstrates that the leaching process follows the surface chemical reaction control kinetic law of "shrinking of unreacted core". The activation energy for pressure leaching high iron sphalerite concentrate is calculated, and a mathematical model for this pressure leaching is obtained. The model is promising to guide the practical operation of pressure leaching high iron sphalerite concentrate.

  7. Mechanochemical leaching of chalcopyrite concentrate by sulfuric acid

    Institute of Scientific and Technical Information of China (English)

    Sina Hejazi; Jalil Vahdati khaki; Abolfazl Babakhani

    2016-01-01

    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 de-termine 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.

  8. Recycling crop residues for use in recirculating hydroponic crop production

    Science.gov (United States)

    Mackowiak, C. L.; Garland, J. L.; Sager, J. C.

    1996-01-01

    As part of bioregenerative life support feasibility testing by NASA, crop residues are being used to resupply elemental nutrients to recirculating hydroponic crop production systems. Methods for recovering nutrients from crop residues have evolved from water soaking (leaching) to rapid aerobic bioreactor processing. Leaching residues recovered the majority of elements but it also recovered significant amounts of soluble organics. The high organic content of leachates was detrimental to plant growth. Aerobic bioreactor processing reduced the organic content ten-fold, which reduced or eliminated phytotoxic effects. Wheat and potato production studies were successful using effluents from reactors having with 8- to 1-day retention times. Aerobic bioreactor effluents supplied at least half of the crops elemental mass needs in these studies. Descriptions of leachate and effluent mineral content, biomass productivity, microbial activity, and nutrient budgets for potato and wheat are presented.

  9. Removal of phosphorus from iron ores by chemical leaching

    Institute of Scientific and Technical Information of China (English)

    JIN Yong-shi; JIANG Tao; YANG Yong-bin; LI Qian; LI Guang-hui; GUO Yu-feng

    2006-01-01

    Alkali-leaching and acid-leaching were proposed for the dephosphorization of Changde iron ore, which contains an average of 1.12% for phosphorus content. Sodium hydroxide, sulfuriced, hydrochloric and nitric acids were used for the preparation of leach solutions. The results show that phosphorus occurring as apatite phase could be removed by alkali-leaching, but those occurring in the iron phase could not. Sulfuric acid is the most effective among the three kinds of acid. 91.61% phosphorus removal was attained with 1% sulfuric acid after leaching for 20 min at room temperature. Iron loss during acid-leaching can be negligible, which was less than 0.25%.The pH value of solution after leaching with 1% sulfuric acid was about 0.86, which means acid would not be exhausted during the process and it could be recycled, and the recycle of sulfuric acid solution would make the dephosphorization process more economical.

  10. WSN中LEACH路由算法的改进%IMPROVING LEACH ROUTING ALGORITHM IN WIRELESS SENSOR NETWORK

    Institute of Scientific and Technical Information of China (English)

    郑少朋; 王涛; 彭刚

    2011-01-01

    For serious imbalance issues of energy consumption of nodes in wireless sensor network, based on tow energy adaptive clustering hierarchy (LEACH) routing algorithm,and integrated with the idea of minimum spanning tree,we propose a new algorithm of LEACH-PD.The algorithm makes reasonable choice of cluster header according to comprehensive reference of residual energy of the nodes as well as the distance between base station and nodes, the inter-cluster communicates with the base station by multi-hop forwarding.Simulation results provided by NS2 showed that, compared with LEACH, the improved LEACH-PD algorithm can effectively prolong the survival time of the network by optimising network load and energy consumption,etc.%针对无线传感器网络节点能耗严重失衡问题,以低功耗自适应聚类LEACH(Low Energy Adaptive Clustering Hierarchy)算法为基础,融合最小生成树的思想,提出一种新的LEACH-PD(Low Energy Adaptive Clustering Hierarchy based on Power and Distance)算法.该算法综合参考节点的剩余能量以及节点到基站的距离合理选择簇首,簇间采用多跳转发的方式与基站进行通信.NS2仿真结果证明,与LEACH算法相比,改进后的LEACH-PD算法在网络负载、能量消耗等方面进行优化,能有效延长网络的生存时间.

  11. Leaching of Electronic Waste Using Biometabolised Acids

    Institute of Scientific and Technical Information of China (English)

    M. Saidan; B. Brown; M. Valix

    2012-01-01

    The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions (or bioacid constituents). The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.

  12. Leaching behavior of butanedionedioxime as gold ligand

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Butanedionedioxime, a small organic compound with low-toxicity and good chemical stability, has been proposed as an effective gold ligand in gold extraction. The result of experiment shows that: 1) highly effective gold lixiviantcan be composed of butanedionedioxime (BDM) with many oxidants, especially potassium permanganate; 2)in the leaching system of BD M- K M nO4 the suitable Ox/Lig(ratio of oxidants to gold ligands) tange is 0.20 ~ 0. 50, optimally 0.25 ~0.45 at the pH range of 7 ~ 11; 3) BDM-KMnO4 extraction of gold from an oxide ore is similar to cyanide(cyanide-O2)extraction, but the leaching rate of gold by BDM-KMnO4 is faster than that by cyanide-O2; 4) gold may readily be recov-ered by carbon adsorption and zinc precipitation

  13. The equilibrium leach testing of CAGR hulls

    International Nuclear Information System (INIS)

    Equilibrium leach tests were carried out on a laboratory scale in order to investigate the long-term performance of an intermediate level waste repository. The tests involved leaching fully active Commercial Advanced Gas-cooled Reactor (CAGR) hulls in the presence of crushed matrix and backfill materials. The matrix materials used were blast furnace slag (BFS)/ordinary Portland cement (OPC) and epoxide MS7531/MS7532, and the backfill materials were bentonite and pulverised fuel ash/ordinary Portland cement (PFA/OPC). Comparison of the long-lived radionuclide concentrations with the derived drinking water levels indicates that the performance of a repository under oxidising conditions would tend to be limited by the release of I-129 and Tc-99. (author)

  14. Leaching from denture base materials in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lygre, H.; Solheim, E.; Gjerdet, N.R. [School of Medicine, Univ. of Bergen (Norway)

    1995-04-01

    Specimens made from denture base materials were leached in Ringer Solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds. 36 refs., 7 figs., 1 tab.

  15. Gold and Silver Extraction from Leach Solutions

    Directory of Open Access Journals (Sweden)

    Bagdaulet K. Kenzhaliyev

    2014-03-01

    Full Text Available There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  16. Alkaline leaching of iron and steelmaking dust

    OpenAIRE

    Stafanova, Anna; Aromaa, Jari

    2012-01-01

    Steel production generates significant quantities of dust and sludge in blast furnaces (BF),basic oxygen furnaces (BOF), and electric arc furnaces (EAF). These dusts contain toxicelements, such as heavy metals, and are thus classified as harmful waste making the disposalof them expensive. In addition, direct recycling of dust back to steel production is hindered dueto the presence of zinc. In this literature survey the alkaline leaching of zinc from iron and steelmaking dusts isreviewed. T...

  17. 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.

  18. Extraction of uranium from coarse ore and acid-curing and ferric sulphate-trickle leaching process

    International Nuclear Information System (INIS)

    On the basis of analysis of the problems in the technology of the traditional uranium hydrometallurgy and the limitations of thin layer leaching process (TLL), a new leaching system-acid-curing and ferric sulphate-trickle leaching (AFL) process (NGJ in Chinese) has developed for extraction of uranium from the coarse ore. The ferric sulphate solution was used for trickling the acid-cured uranium ore and the residual leaching reaction incomplete in TLL process can be improved in this process. And the AFL process has a wide applicability to China's uranium ores, being in competition with the traditional agitation leaching process for treating coarse ores. The uranium ore processing technology based on the AFL process will become one of the new basic technologies of uranium hydrometallurgy. A series of difficulties will be basically overcome associated with fine grinding because of its elimination in the presented process. Moreover, the situation of the present uranium hydrometallurgy can be also changed owing to without technological effluent discharge

  19. Extraction of molybdenum and vanadium from the spent diesel exhaust catalyst by ammonia leaching method

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhipeng; Guo, Min, E-mail: guomin@ustb.edu.cn; Zhang, Mei

    2015-04-09

    Highlights: • Mo and V were extracted from spent diesel exhaust catalyst by ammonia leaching method. • Effects of leaching parameters on the extraction of Mo and V were studied in detail. • The extraction efficiencies of Mo and V could reach 94.96% and 39.73%. • The leaching solution and the residue can be reused for preparing new catalyst. - Abstract: Molybdenum (Mo) and vanadium (V) were effectively extracted from the spent diesel exhaust catalyst (V{sub 2}O{sub 5}–MoO{sub 3}/TiO{sub 2}) by using an ammonia leaching method. Meanwhile, the structure of the spent catalyst carrier (TiO{sub 2}) was not destroyed and might be reused. The effects of ammonia (NH{sub 3}·H{sub 2}O) concentration, leaching temperature and time, concentration of hydrogen peroxide (H{sub 2}O{sub 2}) and liquid to solid ratio on the extraction of Mo and V were systematically investigated. It is shown that the extraction efficiency of Mo increased from 68.68% to 96.45% while the extraction efficiency of V remained stable at 27% with increasing ammonia concentration from 2.95 to 7.38 mol/L, leaching temperature from 298.15 to 473.15 K, and reaction time from 1 to 8 h. With the concentration of H{sub 2}O{sub 2} solution increasing from 1.0 to 2.5 mol/L, the extraction efficiency of V increased from 26.87% to 39.73%. Under the optimum conditions (the ammonia concentration of 4.5 mol/L, leaching temperature of 413.15 K, reaction time of 2 h, the H{sub 2}O{sub 2} solution concentration of 1.0 mol/L and the liquid to solid ratio of 20/1 mL/g), the extraction efficiencies of Mo and V reached 95.13% and 46.25%. Moreover, the catalyst carrier TiO{sub 2} with anatase crystal phase was also obtained.

  20. Economic leaching at Roessing Uranium Limited

    International Nuclear Information System (INIS)

    In the fourteen years that Roessing Uranium Limited has been in production, the metallurgical operations and controls on the leaching plant have envolved through four basic stages. Initially, the emphasis was placed on the achievement of consistent plant operation by overcoming severe start-up difficulties. The second stage involved the attainment of the design operating targets and also the commissioning of the ferric-leaching reactors in order to achieve a ferric ion concentration of more than 3.0 g/l. Improvements in control then became the priority, with the emphasis on consistently achieving the target concentrations of ferric ions, total iron, and terminal acidity. The latest phase has concentrated on the optimization of costs by means of adjustments to the historically established operating parameters in order to achieve large savings on consumables while maintaining the leaching efficiencies. Apart from the obvious incentive of reducing costs in an inflationary economy and a depressed uranium market, impetus for this work was given by a change in the type of ore from the open pit, which has the effect of reducing the extraction efficiency while increasing the consumption of consumable materials. These problems and their solutions are discussed in detail, and the importance to cost-effective optimization of an accurate up-to-date cost-reporting structure is stressed. 9 figs., 2 tabs

  1. CVLEACH: Coverage based energy efficient LEACH algorithm

    Directory of Open Access Journals (Sweden)

    Ankit Thakkar

    2012-06-01

    Full Text Available Designing a protocol stack for wireless sensor network (WSNis a challenging task due to energy, computational and storageconstraints. Energy spent for communication between sensornodes dominates the energy spent for the computation [10].Multi-hop short range communication between wireless sensorsnodes is energy efficient compared to single-hop long rangecommunication. Hierarchical clustering is one of the possiblesolutions to save energy of wireless sensor nodes. Low-EnergyAdaptive Clustering Hierarchy (LEACH, Centralized Low-Energy Adaptive Clustering Hierarchy (LEACH-C andAdvanced Low-Energy Adaptive Clustering Hierarchy(ALEACH are energy efficient hierarchical clustering routingprotocol. In this paper we proposed Coverage based Low-EnergyAdaptive Clustering Hierarchy routing protocol – CVLEACH tomake uniform distribution of Cluster Heads (CHs by creatingnon-overlapped cluster regions using overhearing properties ofthe sensor nodes, which makes the routing protocol more energyefficient and prolongs life time of a wireless sensor network.Simulation results show that CVLEACH improves network lifetime compared to LEACH and ALEACH algorithms.

  2. Pesticide leaching through sandy and loamy fields – Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    International Nuclear Information System (INIS)

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. - Highlights: • Field-results reveal shortcomings in the EU authorization procedure for pesticides. • The plough layer can be bypassed via preferential transport in e.g. wormholes. • Pesticides properties are decisive for leaching pattern on the sandy fields. • The hydrogeological settings control the leaching patterns on the loamy fields. • Pesticide detection frequency seems to be independent of the month of the year. - Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme reveals shortcomings in the European Union authorization procedure for pesticides

  3. Leaching of heavy metals from steelmaking slags

    Directory of Open Access Journals (Sweden)

    Gomes, J. F. P

    2006-12-01

    Full Text Available Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-through test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5 % (Ca and 1% (other elements.

    Este articulo contiene los resultados obtenidos en ensayos de lixiviación de escorias de acero (horno electrico y cuchara ejecutados siguiendo la metodologia de flujo dinámico así como el ensayo normalizado DIN 38414-S4. El primer ensayo intenta simular el comportamiento de lixiviación de las escorias en vertedero. Para las escorias ensayadas se han complementado los ensayos con el análisis químico de los lixiviados y se ha verificado un aumento de la liberación de metales pesados. El ensayo DIN 38414-S4 se ha utilizado para evaluar la lixiviación por agua de metales pesados, en muestras de escorias originales. Despues de un año de ensayos, se han observado niveles muy bajos de lixiviación. Los elementos mas lixiviados han sido calcio y magnesio. No obstante, en los ensayos de flujo dinámico, el calcio y el magnesio lixiviados de las escorias sólidas era menor de 0,5% y el resto de los otros metales era inferior a 0,1%. Los lixiviados obtenidos con el ensayo DIN 38414-S4 presentan, como era de esperar, valores

  4. DYNAMIC RE-CLUSTERING LEACH-BASED (DR-LEACH PROTOCOL FOR WIRELESS SENSOR NETWORKS

    Directory of Open Access Journals (Sweden)

    Abdallah Ijjeh

    2015-11-01

    Full Text Available A Wireless Sensor Network (WSN contains a large number of sensor nodes equipped with limited energy supplies. In most applications, sensor nodes are deployed in a random fashion. Therefore, battery replacement or charging is considered not practical. As a result, routing protocols must be energy-efficient to prolong the network’s lifetime. In this paper, we propose a new Dynamic Re-clustering LEACH-Based protocol (DR-LEACH which aims to reduce the energy consumption and extending the network’s lifetime. The idea is to balance energy consumption of Cluster Heads (CHs by generating clusters with almost equal number of nodes during each round of the network life time. To perform this, we first calculate the optimal number of CHs in each round, and based on that we calculate the optimal size of each cluster. Results show that the proposed protocol improves network lifetime and reduces overall energy consumption compared to LEACH and BCDCP protocols.

  5. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Both crushed (150 to 300 μm) and cored (1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 and 750C and leachates were 0.03 N NaHCO3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads Cs leach rates from SYNROC compare well with both Na and Np leached from the glass. The other elements leached from SYNROC are lower than Na and Np leached from glass. They also vary for each element while glass shows nearly the same leach rate for both Na and Np

  6. Process Optimization for Valuable Metal Recovery from Dental Amalgam Residues

    Directory of Open Access Journals (Sweden)

    C.M. Parra–Mesa

    2009-07-01

    Full Text Available In this paper, the methodology used for optimizing leaching in a semi pilot plant is presented. This leaching process was applied to recover value metals from dental amalgam residues. 23 factorial design was used to characterize the process during the first stage and in the second one, a central compound rotational design was used for modeling copper percentage dissolved, a function of the nitric acid concentration, leaching time and temperature. This model explained the 81% of the response variability, which is considered satisfactory given the complexity of the process kinetics and, furthermore, it allowed the definition of the operation conditions for better copper recovery, which this was of 99.15%, at a temperature of 55°C, a concentration of 30% by weight and a time of 26 hours.

  7. Residues from waste incineration. Final report. Rev. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Astrup, T.; Juul Pedersen, A.; Hyks, J.; Frandsen, F.J.

    2010-04-15

    The overall objective of the project was to improve the understanding of the formation and characteristics of residues from waste incineration. This was done focusing on the importance of the waste input and the operational conditions of the furnace. Data and results obtained from the project have been discussed in this report according to the following three overall parts: i) mass flows and element distribution, ii) flue gas/particle partitioning and corrosion/deposition aspects, and iii) residue leaching. This has been done with the intent of structuring the discussion while tacitly acknowledging that these aspects are interrelated and cannot be separated. Overall, it was found that the waste input composition had significant impact of the characteristics of the generated residues. A similar correlation between operational conditions and residue characteristics could not be observed. Consequently, the project recommend that optimization of residue quality should focus on controlling the waste input composition. The project results showed that including specific waste materials (and thereby also excluding the same materials) may have significant effects on the residue composition, residue leaching, aerosol and deposit formation.It is specifically recommended to minimize Cl in the input waste. Based on the project results, it was found that a significant potential for optimization of waste incineration exist. (Author)

  8. Selective leaching studies of sediments from a seamount flank in the Central Indian Basin: Resolving hydrothermal, volcanogenic and terrigenous sources using major, trace and rare-earth elements

    Digital Repository Service at National Institute of Oceanography (India)

    Mascarenhas-Pereira, M.B.L.; Nath, B.N.

    seamount in the Central Indian Basin along the 76 degrees 30 minutes E fracture zone which traces the movement of the Rodriguez triple junction. Detailed analyses of major, trace and rare earth elements (REE) on the bulk, leach, residue and clay fraction...

  9. Lead Enrichment from Lead-Bearing Zinc Residue%含铅锌渣中铅的富集

    Institute of Scientific and Technical Information of China (English)

    何静; 罗超; 鲁君乐; 王小能; 王涛; 韩生菁

    2012-01-01

    提出低酸—高酸两段逆流浸出含铅锌渣新工艺,低酸浸出考察液固比、时间和温度对锌浸出率的影响,高酸浸出考察初始硫酸浓度、时间和温度对锌浸出率及铅品位的影响.结果表明,在低酸浸出,液固比6∶1、时间5h、温度60℃;高酸浸出,初始硫酸浓度170 g/L、时间6h、温度95℃的最优条件下,锌浸出率99.29%,铅入渣率98.58%,高浸渣中铅品位62.25%.%A new process of zinc leaching from lead-bearing zinc residue with low and high acidity counter-current process were studied. The effects of ratio of liquid to solid (L/S), time and temperature on zinc leaching rate were investigated in low acidity leaching process; while the effects of initial H2SO4 concentrations, time and temperature on zinc leaching rate and lead content in high acidity leaching process were investigated. The results show that the leaching ratio of zinc can reach-99. 29%, 98. 25% of lead remains in high acidity leaching residues, the content of lead can reach 62. 25% in high acidity leaching residues under the following optimum conditions, which are L/S of 6 : 1, reaction time of 5 h, temperature of 60 ℃ in low acidity leaching process; While initial acid concentration of 170 g/L, reaction time of 6 h and temperature of 95 ℃ in high acidity leaching process.

  10. Leaching and recycling of zinc from liquid waste sediments

    Institute of Scientific and Technical Information of China (English)

    PENG Bing; GAO Hui-mei; CHAI Li-yuan; SHU Yu-de

    2008-01-01

    The selective leaching and recovery of zinc in a zinciferous sediment from a synthetic wastewater treatment was investigated. The main composition of the sediment includes 6% zinc and other metal elements such as Ca, Fe, Cu, Mg. The effects of sulfuric acid concentration, temperature, leaching time and the liquid-to-solid ratio on the leaching rate of zinc were studied by single factor and orthogonal experiments. The maximum difference of leaching rate between zinc and iron, 89.85%, was obtained by leaching under 170 g/L H2SO4 in liquid-to-solid ratio 4.2 mL/g at 65 "C for 1 h, and the leaching rates of zinc and iron were 91.20% and 1.35%, respectively.

  11. Impact of weather variability on nitrate leaching

    Science.gov (United States)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  12. Leaching refuse after sphalerite mineral for extraction zinc and cobalt

    Directory of Open Access Journals (Sweden)

    S. Brožová

    2016-07-01

    Full Text Available The paper deals with a possibility of zinc and cobalt extraction from refuse after sphalerite mineral leaching. It contains theoretic analysis of hydrometallurgical processes. Practical part describes samples and their leaching in 10 % and 20 % sulphuric acid. In the end of the paper it is evaluated under which conditions the highest yield of zinc and cobalt from refuse after sulphide ore leaching is reached.

  13. 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.

  14. Leaching of vanadium from sulphuric acid manufacture spent catalysts

    OpenAIRE

    García, Diego Juan; Lozano Blanco, Luis Javier; Mulero Vivancos, María Dolores

    2001-01-01

    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 ...

  15. Leaching refuse after sphalerite mineral for extraction zinc and cobalt

    OpenAIRE

    S. Brožová; J. Drápala; Kursa, M.; Pustějovská, P.; S. Jursová

    2016-01-01

    The paper deals with a possibility of zinc and cobalt extraction from refuse after sphalerite mineral leaching. It contains theoretic analysis of hydrometallurgical processes. Practical part describes samples and their leaching in 10 % and 20 % sulphuric acid. In the end of the paper it is evaluated under which conditions the highest yield of zinc and cobalt from refuse after sulphide ore leaching is reached. Web of Science 55 3 499 497

  16. 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. PMID:25712610

  17. Coupling GIS with Nitrogen Leaching Models

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Geographical information systems (GIS) are increasingly being applied to surface and subsurface flow and transport modeling issues. In this paper, more attentions are focused on the methodology and strategies of coupling GIS with non-point pollution models. Suggestions are made on how to best integrate current available or selected nitrogen leaching models, especially in the aspect of programming development so as to effectively and flexibly address the specific tasks. The new possibilities for dealing with non-point pollution problems at a regional scale are provided in the resulting integrated approach, including embedding grid-based GIS components in models.

  18. Influence of Jarosite Generation on Leaching of Indium From Zinc Oxide Powder%矾的生成对次氧化锌中铟浸出的影响

    Institute of Scientific and Technical Information of China (English)

    陈国木; 李国峰; 曾鹏; 王秋银; 王娜; 黄孟阳

    2015-01-01

    次氧化锌浸出铟后的浸出渣中含有大量矾,从理论上分析了矾产生的原因,考察了浸出过程中控制酸度及添加过量添加剂对铟浸出率的影响,提出了控制矾的生成及破坏矾从而提高铟浸出率的措施。生产实践表明,采取相应措施,铟浸出率可从60%提高至85%以上,浸出渣中铟质量分数可从900 g/t降至100~200 g/t。%There is a lot of jarosite in the leaching residue in the process of low acidic leaching of indium from zinc oxide powder .The generation reasons of jarosite was analyzed .The influence of leaching agent acidity and appropriate additive on leaching of indium w ere examined .T he measures of controlling jarosite generation and destroying jarosite then increasing leaching of indium were pointed out .The production practice shows that leaching rate of indium can increase from 60% to over 85% , mass fraction of indium in leaching residue can decrease to 100-200 g/t .

  19. Cadmium leaching from thermal treated and gamma irradiated Mexican aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Davila-Rangel, J.I. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico 11801, D.F. (Mexico); Unidad Academica Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas Cipres 10, Frac. La Penuela, Zacatecas, Zacatecas 98068 (Mexico); Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario No. 100 Col. Centro C.P. 50000, Toluca, Edo. de Mexico (Mexico); Solache-Rios, M. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico 11801, D.F. (Mexico)], E-mail: msr@nuclear.inin.mx

    2008-10-15

    Thermal and radiation effects on the leaching of cadmium from two cadmium exchanged zeolitic tuffs and one clay were determined. The cadmium exchanged aluminosilicates were heated at different temperatures (500, 700, 900 and 1100 {sup o}C), and the materials were then treated with NaCl (1 M and 5 M) and HNO{sub 3} (0.001 M and 1 M) solutions to determine the leaching behaviour of cadmium from the materials. The stability of cadmium in the materials increased as the heating temperature was increased. Cadmium leaching from gamma irradiated and heated materials at 1100 {sup o}C was higher than leaching from non-irradiated samples.

  20. Electrogenerative leaching of nickel sulfide concentrate with ferric chloride

    Institute of Scientific and Technical Information of China (English)

    王少芬; 方正; 王云燕; 陈阳国

    2004-01-01

    In order to utilize the chemical energy in hydrometallurgical process of sulfide minerals reasonably and to simplify the purifying process, the electrogenerative process was applied and a dual cell system was introduced to investigate FeCl3 leaching of nickel sulfide concentrate. Some factors influencing the electrogenerative leaching, such as electrode structure, temperature and solution concentration were studied. The results show that a certain quantity of electrical energy accompanied with the leached products can be acquired in the electrogenerative leaching process.The output current and power increase with the addition of acetylene black to the electrode. Varying the components of electrode just affects the polarization degree of anode. Increasing FeCl3 concentration results in a sharp increase in the output of the leaching cell when c(FeCl3) is less than 0.1 mol/L. The optimum value of NaCl concentration for electrogenerative leaching nickel sulfide concentrate with FeCl3 is 3.0 mol/L. Temperature influences electrogenerative leaching by affecting anodic and cathodic polarization simultaneously. The apparent activation energy is determined to be 34.63 kJ/mol in the range of 298 K to 322 K. The leaching rate of Ni2+ is 29.3% after FeCl3 electrogenerative leaching of nickel sulfide concentrate for 620 min with a filter bag electrode.

  1. Leaching of polyphase nuclear waste ceramics: microstructural and phase characterization

    International Nuclear Information System (INIS)

    The leaching of complex polyphase nuclear waste ceramics is described in the context of the geochemically established dissolution behavior of the constituent phases. Static leach tests conducted on ceramic monoliths in deionized water, in simulated silicate, and in brine groundwaters, conforming to Materials Characterization Center standards and an accelerated, microscopic leach test, were used to identify the processes. Dissolution and formation of surface passivation layers are discussed in terms of hydrolysis and the adsorption of the metal hydroxocomplexes onto the monolith surface. The factors observed to affect dissolution are pertinent to the leaching of other polyphase nuclear waste ceramics. 11 figures, 1 table

  2. Effect of peroxodisulfate on uranium leaching with ammonium bicarbonate

    Directory of Open Access Journals (Sweden)

    Nurbek Nurpeisov

    2013-05-01

    Full Text Available In this study, uranium leaching from ore material using acid solution and bicarbonate in a presence peroxodisulfate ion was examined. For experiments two different tips of leaching methods were used: leaching in static and dynamic conditions. The determination of uranium concentrations in product solutions were analyzed by titrimetric (by ammonia vanadate solution method. The maximum yield of uranium leached with ammonium bicarbonate in a presence of ammonium peroxodisulfate (5 g/L was only 33%, which is half the corresponding value obtained by sulfuric acid (65%.

  3. Carbonate leaching of uranium and hydrogen peroxide stabilizer therefor

    International Nuclear Information System (INIS)

    In the carbonate leaching process for the solution mining of subterranean uranium containing formations in which an injection well is drilled and completed within the uranium formation; alkaline carbonate uranium leaching solution and sufficient hydrogen peroxide are injected through the injection wells into the formation whereby uranium values are produced from production wells, characterized by providing in the leaching solution a mixture of 1-hydroxyethylidene-1,1-diphosphonic acid and an alkali metal pyrophosphate in a weight ratio of from 1 to 10 to 10 to 1, the amount of said mixture being sufficient to inhibit decomposition of the hydrogen peroxide in said leaching solution

  4. Cadmium leaching from thermal treated and gamma irradiated Mexican aluminosilicates

    International Nuclear Information System (INIS)

    Thermal and radiation effects on the leaching of cadmium from two cadmium exchanged zeolitic tuffs and one clay were determined. The cadmium exchanged aluminosilicates were heated at different temperatures (500, 700, 900 and 1100 oC), and the materials were then treated with NaCl (1 M and 5 M) and HNO3 (0.001 M and 1 M) solutions to determine the leaching behaviour of cadmium from the materials. The stability of cadmium in the materials increased as the heating temperature was increased. Cadmium leaching from gamma irradiated and heated materials at 1100 oC was higher than leaching from non-irradiated samples

  5. Actinide speciation in glass leach-layers: An EXAFS study

    Energy Technology Data Exchange (ETDEWEB)

    Biwer, B.M.; Soderholm, L. [Argonne National Lab., IL (United States); Greegor, R.B. [Boeing Co., Seattle, WA (United States); Lytle, F.W. [EXAFS Co., Pioche, NV (United States)

    1996-12-31

    Uranium L{sub 3} X-ray absorption data were obtained from two borosilicate glasses, which are considered as models for radioactive wasteforms, both before and after leaching. Surface sensitivity to uranium speciation was attained by a novel application of simultaneous fluorescence and electron-yield detection. Changes in speciation are clearly discernible, from U(VI) in the bulk to (UO{sub 2}){sup 2+}-uranyl in the leach layer. The leach-layer uranium concentration variations with leaching times are also determined from the data.

  6. 锌渣氧粉两段浸出铟的试验研究%Test Research on Two-stages Leaching of Indium From Zinc Oxidation Slag

    Institute of Scientific and Technical Information of China (English)

    谌斯; 杨利姣; 陈南春; 高军; 刘显妙; 周翠澎; 朱晓岗

    2013-01-01

    Leaching of indium from zinc oxidation slag by two-stages leaching process was studied .The effects of sulfuric acid initial concentration ,leaching time ,the ratio between liquid and solid , temperature ,activated time and KMnO4 dosage on leaching of indium were examined .The results show that the indium is enriched in neutral leaching residue after first-stage leaching .Leaching of indium can be enhanced obviously by mechanical activation ,but atmospheric oxidation doesn't improve the leaching of indium .T he optimum leaching conditions in second-stage leaching process are sulfuric acid initial concentration of 300 g/L ,leaching time of 3 h ,the ratio between liquid and solid 3 ∶ 1 , temperature of 85 ℃ ,mechanically activated of 60 min .Under the optimum conditions ,leaching rate of indium is 90 .9% .%研究了以两段浸出工艺从含铟锌渣氧粉中浸出铟。试验主要考察了两段酸性浸出中,硫酸初始质量浓度、浸出时间、液固体积质量比、温度、机械活化时间、氧化剂用量等对铟浸出率的影响。试验结果表明:中性浸出对铟有明显的富集作用,机械活化可以强化铟的浸出,常压氧化对铟的强化浸出效果不明显;在硫酸初始质量浓度300 g/L、浸出时间3 h、液固体积质量比3∶1、温度85℃、机械活化60 min的最佳条件下,铟浸出率为90.9%。

  7. YACON INULIN LEACHING DURING HOT WATER BLANCHING

    Directory of Open Access Journals (Sweden)

    Caroline Fenner Scher

    2015-10-01

    Full Text Available ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching under different time/temperature conditions. The samples were cleaned and peeled and cut into geometric forms of 1.75 ± 0.35 mm thick disks. A complete factorial experimental design was used, and the treatments of the samples were compared using the Tukey test. The results indicated that the time and temperature were significant in the dissolution of the sugars. The lowest inulin losses occurred at temperatures and times lower than 60 ºC and 3 minutes. For all temperatures, the lowest glucose and fructose losses were obtained at time lower than 3 and 5 minutes, respectively.

  8. Heterogeneous LEACH Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Nishi Sharma

    2013-07-01

    Full Text Available Wireless Sensor Networks are networks of large number of tiny, battery powered sensor nodes having limited on-board storage, processing, and radio capabilities. Nodes sense and send their reports toward a processing center which is called base station. Since this transmission and reception process consumes lots of energy as compare to data processing, Designing protocols and applications for such networks has to be energy aware in order to prolong the lifetime of the network. Generally, real life applications deal with such Heterogeneity rather than Homogeneity. In this paper, a protocol is proposed, which is heterogeneous in energy. We analyze the basic distributed clustering routing protocol LEACH (Low Energy Adaptive Clustering Hierarchy, which is a homogeneous system, and then we study the impact of heterogeneity in energy of nodes to prolong the life time of WSN. Simulation results using MATLAB shows that the proposed Leach-heterogeneous system significantly reduces energy consumption and increase the total lifetime of the wireless sensor network.

  9. 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.

  10. 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.

  11. Transmission Time and Throughput analysis of EEE LEACH, LEACH and Direct Transmission Protocol: A Simulation Based Approach

    Directory of Open Access Journals (Sweden)

    Meenakshi Sharma

    2012-10-01

    Full Text Available This paper gives a brief description about some routing protocols like EEE LEACH, LEACH and DirectTransmission protocol (DTx in Wireless Sensor Network (WSN and a comparison study of theseprotocols based on some performance matrices. Addition to this an attempt is done to calculate theirtransmission time and throughput. To calculate these, MATLAB environment is used. Finally, on the basisof the obtained results from the simulation, the above mentioned three protocols are compared. Thecomparison results show that, the EEE LEACH routing protocol has a greater transmission time thanLEACH and DTx protocol and with smaller throughput

  12. Transmission Time and Throughput analysis of EEE LEACH, LEACH and Direct Transmission Protocol: A Simulation Based Approach

    Directory of Open Access Journals (Sweden)

    Meenakshi Sharma

    2012-12-01

    Full Text Available This paper gives a brief description about some routing protocols like EEE LEACH, LEACH and DirectTransmission protocol (DTx in Wireless Sensor Network (WSN and a comparison study of theseprotocols based on some performance matrices. Addition to this an attempt is done to calculate theirtransmission time and throughput. To calculate these, MATLAB environment is used. Finally, on the basisof the obtained results from the simulation, the above mentioned three protocols are compared. Thecomparison results show that, the EEE LEACH routing protocol has a greater transmission time thanLEACH and DTx protocol and with smaller throughput.

  13. Selective leaching process for the recovery of copper and zinc oxide from copper-containing dust.

    Science.gov (United States)

    Wu, Jun-Yi; Chang, Fang-Chih; Wang, H Paul; Tsai, Ming-Jer; Ko, Chun-Han; Chen, Chih-Cheng

    2015-01-01

    The purpose of this study was to develop a resource recovery procedure for recovering copper and zinc from dust produced by copper smelting furnaces during the manufacturing of copper-alloy wires. The concentrations of copper in copper-containing dust do not meet the regulation standards defined by the Taiwan Environmental Protection Administration; therefore, such waste is classified as hazardous. In this study, the percentages of zinc and copper in the dust samples were approximately 38.4% and 2.6%, respectively. To reduce environmental damage and recover metal resources for industrial reuse, acid leaching was used to recover metals from these inorganic wastes. In the first stage, 2 N of sulphuric acid was used to leach the dust, with pH values controlled at 2.0-3.0, and a solid-to-liquid ratio of 1:10. The results indicated that zinc extraction efficiency was higher than 95%. A selective acid leaching process was then used to recover the copper content of the residue after filtration. In the second stage, an additional 1 N of sulphuric acid was added to the suspension in the selective leaching process, and the pH value was controlled at 1.5-2.0. The reagent sodium hydroxide (2 N) was used as leachate at a pH greater than 7. A zinc hydroxide compound formed during the process and was recovered after drying. The yields for zinc and copper were 86.9-93.5% and 97.0-98.9%, respectively. PMID:25191877

  14. A study on the selection of indigenous leaching-bacteria for effective bioleaching

    Science.gov (United States)

    Oh, S. J.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

    2012-04-01

    Bioleaching technology, which is based on the ability of microorganisms to transform solid compounds into soluble and extractable valuable elements that can be recovered, has been rapidly developed in recent decades for its advantages, which include mild reaction condition, low energy consumption, simple process, low environmental impact and being suitable for low grade mine tailings and residues. The bacteria activities (survival, adaptation of toxically environments etc.) in the bioleaching technology play a key role in the solubilization of metals. The purpose of this study was to selection of optimal leaching-bacteria through changed pH and redox potential on bio-oxidation in batch experiments for successful bioleaching technology. Twenty three indigenous bacteria used throughout this study, leaching-bacteria were obtained from various geochemical conditions; bacteria inhabitation type (acid mine drainage, mine wastes leachate and sulfur hot springs) and base-metal type (sulfur, sulfide, iron and coal). Bio-oxidation experiment result was showed that 9 cycles (1 cycle - 28days) after the leaching-bacteria were inoculated to a leaching medium, pH was observed decreasing and redox potential increased. In the bacteria inhabitation type, bio-oxidation of sulfur hot springs bacteria was greater than other types (acid mine drainage and mine wastes leachate). In addition, bio-oxidation on base-metal type was appeared sulfur was greater than other types (sulfide, iron and coal). This study informs basic knowledge when bacteria apply to eco-/economic resources utilization studies including the biomining and the recycling of mine waste system.

  15. Uranium recovery by leaching with sodium carbonate at high temperature and pressure

    International Nuclear Information System (INIS)

    The principal uranium bearing mineral in Greenland steenstrupine is a complex sodium REE phosphosilicate in which Fe, Mn, Th, U are minor constituents. The Na2CO3 extractant is used for specially acidconsuming ores. However, steenstrupine is decomposed by Na2CO3 only at temperatures above 220degC, so the leaching must be carried out under pressure. Laboratory tests have shown the optimal temperature to be 260degC and the leach liquor composition120 g/l of NaHCO3 and 20 g/l of Na2CO3. Addition of oxygen is necessary as uranium will not dissolve in carbonate unless it is brought in its highest state of oxidation. According to the laboratory tests it may be estimated that 1 kg of ore suspended in 1 l of leach liquor and ground to 80% minus 200 mesh can be extracted in 20-40 minutes. On the basis of data obtained a process was suggested in which the ore is ground with carbonate leach liquor to a suitable suspension which is fed to an autoclave with a retentiontime of 20 minutes at 260degC. The residue is filtered off and the liquor reused for grinding and ex- traction. The demand for a reaction temperature near 300degC, a pressure up to 120 atm. and a continuos operation favours a tubular flow autoclave with so narrow a bore that the turbulence provides the mechanical agitation of the suspension. From the mined material it appears that more than 80% of the uranium can be extracted in the pipe autoclave. Some samples give off the obtainable uranium in 20 minutes. The precipitated yellow cake is contaminated with more Na and Si than admitted by international standards. (EG)

  16. Environmental impact of APC residues from municipal solid waste incineration: Reuse assessment based on soil and surface water protection criteria

    International Nuclear Information System (INIS)

    Highlights: → The Dutch Building Material Decree (BMD) was used to APC residues from MSWI. → BMD is a straightforward tool to calculate expectable loads to the environment of common pollutants. → Chloride load to the environment lead to classification of building material not allowed. → At least a pre-treatment (e.g. washing) is required in order to remove soluble salts. → The stabilization with phosphates or silicates eliminate the problem of heavy metals. - Abstract: Waste management and environmental protection are mandatory requirements of modern society. In our study, air pollution control (APC) residues from municipal solid waste incinerators (MSWI) were considered as a mixture of fly ash and fine particulate solids collected in scrubbers and fabric filters. These are hazardous wastes and require treatment before landfill. Although there are a number of treatment options, it is highly recommended to find practical applications rather than just dump them in landfill sites. In general, for using a construction material, beyond technical specifications also soil and surface water criteria may be used to ensure environmental protection. The Dutch Building Materials Decree (BMD) is a valuable tool in this respect and it was used to investigate which properties do not meet the threshold criteria so that APC residues can be further used as secondary building material. To this end, some scenarios were evaluated by considering release of inorganic species from unmoulded and moulded applications. The main conclusion is that the high amount of soluble salts makes the APC residues a building material prohibited in any of the conditions tested. In case of moulding materials, the limits of heavy metals are complied, and their use in Category 1 would be allowed. However, also in this case, the soluble salts lead to the classification of 'building material not allowed'. The treatments with phosphates or silicates are able to solve the problem of heavy metals, but

  17. Incorporation feasibility of leather residues in bricks

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, J.B. [Minho Univ. (Portugal). Civil Engineering Dept.; Valente, A.; Pires, M.J. [Inst. of Development and Innovation Technology of Minho, Braga (Portugal); Tavares, T. [Biological Engineering Dept., Univ. of Minho, Braga (Portugal)

    2002-07-01

    The footwear industry has strips of leather as one of its by-products. These leather residues, due to their high chromium content, can be regarded as a threat to the environment, particularly if no care is taken with their disposal. With the incorporation of the residues in ceramic products, after trituration, is possible to neutralise the eventual toxicity of chromium. In a laboratory study we produced prismatic bricks using clay from the region and incorporating 1, 3 and 5% (by mass) of leather residues. This corresponds at about 20, 60 and 100% (by apparent volume). The moulds were filled up with paste and, in order to have some compactness, the ceramic paste was compressed with a spatula. After that, it began the process of drying and burning the bricks. They were tested to flexure, compression and leaching. The results showed that the toxicity of chromium disappeared in the bricks. The mechanical tests showed a decrease in strength for the specimens with leather residue. The compressive strength decreases about 22% for 1% of incorporation of leather residue. However, as bricks were lighter and more porous, we can expect that they are better for thermal isolation. (orig.)

  18. 空气氧化—氨浸出废旧电路板中的铜%Ammonia-Ammonium Sulfate Copper Leaching from Waste Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    张有新; 李静; 潘发芳

    2013-01-01

    A novel hydrometallurgical process of copper recovery from waste printed circuit boards was introduced. In this process, air was blown into solution as oxidant for copper leaching in NH3-(NH4)2SO4-H2O system, while leaching residue was treated by physical method. The effects of ammonia and ammonium sulfate concentration, ratio of solid to liquid, leaching temperature, air flow and leaching time on copper leaching rate were investigated. The results show that copper leaching rate is up to 96. 67% under the following optimum conditions including ammonia concentration of 2 mol/L, ammonium sulfate concentration of 2 mol/L, ratio of solid to liquid of 1 : 20, leaching temperature of 25 ℃ , air flow of 8 m3/h and leaching time of 4 h.%提出了在氨水—硫酸铵体系下鼓入空气浸出废旧电路板中铜的新工艺.考察了氨水浓度、硫酸铵浓度、固液比、反应温度、通入空气流量和浸出时间对铜浸出率的影响.结果表明,在下述最佳浸出条件下,渣计铜浸出率达到96.67%:氨水浓度2 mol/L,硫酸铵浓度2 mol/L,固液比1∶20,反应温度25℃、通入空气量8 m3/h、浸出时间4h.

  19. Thermodynamic Model for Uranium Release from Hanford Site Tank Residual Waste

    International Nuclear Information System (INIS)

    A thermodynamic model of U phase solubility and paragenesis was developed for Hanford tank residual waste that will remain after tank closure. The model was developed using a combination of waste composition data, waste leach test data, and thermodynamic modeling of the leach test data. The testing and analyses were conducted using actual Hanford tank residual waste. Positive identification of the U phases by X-ray diffraction (XRD) was generally not possible because solids in the waste were amorphous, or below the detection limit of XRD for both as-received residual waste and leached residual waste. Three leachant solutions were used in the studies, dionized water, CaCO3 saturated solution, and Ca(OH)2 saturated solution. Thermodynamic modeling verified that equilibrium between U phases in the initial residual waste samples and the leachants was attained in less than a month. The paragenetic sequence of secondary phases that occur as waste leaching progresses for two closure scenarios was identified. These results have significant implications for tank closure design.

  20. Phosphorus Availability in Soils Amended with Wheat Residue Char

    OpenAIRE

    Parvage, Md. Masud; Ulén, Barbro; Eriksson, Jan; Strock, Jeffery; Kirchmann, Holger

    2013-01-01

    Plant availability and risk for leaching and/or runoff losses of phosphorus (P) from soils depends among others on P concentration in the soil solution. Water soluble P in soil measures soil solution P concentration. The aim of this study was to understand the effect of wheat residue char (biochar) addition on water soluble P concentration in a wide range of biochar amended soils. Eleven agricultural fields representing dominant soil texture classes of Swedish agricultural lands were chosen. ...

  1. Organic ligands influence leaching kinetics of fixated FGD material

    Energy Technology Data Exchange (ETDEWEB)

    Chin-Min Cheng; Yu Sik Hwang; John J. Lenhart; Harold W. Walker [Ohio State University, Columbus, OH (United States). Department of Civil and Environmental Engineering and Geodetic Science

    2008-10-15

    The presence of organic ligands, including oxalate, citrate, maleate and Pahokee peat humic acid (PPHA), influenced the leaching kinetics of fixated flue gas desulfurization (FGD) material in acidic solution (pH 2.9-5.0). In the presence of oxalate, the leaching was inhibited at all pH values examined. XRD and SEM analyses demonstrated that formation of a calcium oxalate mineral phase on the fixated FGD material surface created a surface layer which reduced the extent of leaching. Maleate and PPHA inhibited leaching at pH 2.9, but either promoted, inhibited, or had no effect on leaching, depending on the particular element, at pH 5.0. ATR-FTIR analysis indicated maleate and PPHA formed both inner- and outer-spherically bound species at pH 2.9, whereas at pH 5.0 only outer-sphere complexes seemed evident. These surface species likely inhibited the leaching process at pH 2.9 through a surface blocking mechanism. At pH 5.0, the ligand surface complexes either promoted or inhibited leaching, depending on the element, through a combination of direct and indirect mechanisms. Citrate significantly promoted the leaching process at all pH values examined. 43 refs., 6 figs., 3 tabs.

  2. Leaching of polyphase nuclear waste ceramics: microstructural and phase characterization

    International Nuclear Information System (INIS)

    Alumina-based ceramics are potential materials for storage of nuclear wastes. Static leach tests conducted on ceramic monoliths in deionized water, in simulated silicate, and in brine groundwaters, conforming to Materials Characterization Center standards and an accelerated, microscopic leach test, were used to identify the processes. Dissolution and formation of surface passivation layers are discussed. 40 refs

  3. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  4. Accelerated Leach Test(s) Program: Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.

    1986-09-01

    A computerized data base of LLW leaching data has been developed. Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms containing simulated wastes are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms.

  5. Manual of acid in situ leach uranium mining technology

    International Nuclear Information System (INIS)

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology

  6. Pesticide leaching in macroporous clay soils: field experiment and modeling

    NARCIS (Netherlands)

    Scorza Júnior, R.P.

    2002-01-01

    Keywords : pesticide leaching, macropores, preferential flow, preferential transport, cracked clay soil, pesticide leaching models, groundwater contamination, inverse modeling, bentazone and imidacloprid. The presence of macropores (i.e. shrinkage c

  7. Water flow and nitrate leaching in a layered silt loam

    NARCIS (Netherlands)

    Vos, J.A.; Hesterberg, D.L.R.; Raats, P.A.C.

    2000-01-01

    Nitrate (NO3) leaching was studied for a winter leaching period in a layered calcareous silt loam with tile-drains at about 1-m depth and 12-m spacing. Groundwater levels, drain discharge rates, and NO3 concentrations in the drainage water were monitored, and the soil hydraulic characteristics were

  8. PLEASE: a simple model to determine P losses by leaching

    NARCIS (Netherlands)

    Schoumans, O.F.; Salm, van der C.; Groenendijk, P.

    2013-01-01

    Non-point phosphorus (P) loss from agricultural land to streams is caused mainly by overland flow and leaching. In many countries P-index methods are used to identify areas at risk of P loss to streams. In flat areas with shallow groundwater levels, where losses by leaching are important, these inde

  9. Direct Sulfuric Acid Leaching of A Lead-zinc Oxide Ore%氧化铅锌矿直接硫酸浸出

    Institute of Scientific and Technical Information of China (English)

    贺山明; 王吉坤; 李勇

    2011-01-01

    The direct sulfuric acid leaching process of lead-zinc oxide ore is investigated, and the impact factors on leaching are described. The results show that the more than 97% of zinc can be leached, more than 98% of lead into the slag, the rate of fluid production is greater than 162. 5L/m2 · H, the zinc content in residue is about 2. 5% and the lead content in residue is greater than 40% , under the optimal condition. The leaching residue can be sent to the lead smelting process.%探讨用硫酸直接浸出氧化铅锌矿,研究各种因素对浸出的影响.结果表明,在最佳工艺条件下,锌的浸出率可达97%以上,铅入渣率可达98%以上,产液速率大于162.5L/m2·h,渣含锌约2.5%,渣含铅量高达40%以上,浸出渣可送往炼铅系统处理.

  10. Leaching characteristics of paraffin waste package with pinhole

    International Nuclear Information System (INIS)

    An Effect of pinhole(perforation or pit penetration) that might be formed outside the package on the nuclide leaching from paraffin waste form was investigated. In case of single pinhole, the leached mass and cumulative fraction leached (CFL) increased with the larger diameter of pinhole, but they were not in direct proportion to the size or area of pinhole. If the total area of multiple pinholes was fixed, the leached mass showed a tendency to increase as each size was smaller and the number was more. It was also found that the leached mass was not in direct proportion to the number of pinhole in case of constant size. In order to analyze the test results, the shrinking core model(SCM) was derived from the diffusion-controlled dissolution reaction and compared with previous diffusion model

  11. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    HARRINGTON SJ

    2011-01-06

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  12. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    International Nuclear Information System (INIS)

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  13. Synergistic Effect of Nanosilica Aerogel with Phosphorus Flame Retardants on Improving Flame Retardancy and Leaching Resistance of Wood

    Directory of Open Access Journals (Sweden)

    Xiaodan Zhu

    2014-01-01

    Full Text Available Nanosilica (Nano-SiO2 sol fabricated by a sol-gel process was introduced into wood modification with phosphorus flame retardants to improve the flame retardancy and leaching resistance of wood. The obtained materials were characterized by scanning electron microscopy and energy dispersive spectrometer (SEM-EDS, thermogravimetric analysis (TGA, cone calorimetric (CONE, and infrared spectroscopy (FT-IR. The residual rate of flame retardants before and after leaching was determinated by a leaching resistance. The results showed that the phosphorus flame retardants and SiO2 sol could reside in the poplar wood and are widely distributed in the vessels, pits, wood timber, and the spaces between wood cells of poplar substrate. TGA and CONE results indicated that the introduction of nano-SiO2 aerogel with phosphorus flame retardants had a significantly synergistic effect on improving the flame retardancy and inhibiting the release of smoke and toxic gases. In addition, the leaching resistance test, combined with infrared analysis and EDS analysis, confirmed that the phosphorus flame retardants were able to be fixed by SiO2 aerogel in the wood.

  14. Leaching optimization of municipal solid waste incineration ash for resource recovery: A case study of Cu, Zn, Pb and Cd.

    Science.gov (United States)

    Tang, Jinfeng; Steenari, Britt-Marie

    2016-02-01

    Ash from municipal solid waste incineration (MSWI) may be quite cumbersome to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as toxic metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of copper, zinc and lead from MSWI ashes, for example, will not only provide valuable metals that would otherwise be landfilled but also give an ash residue with lower concentrations of toxic metals. In this work, fly ash and bottom ash from an MSWI facility was used for the study and optimization of metal leaching using different solutions (nitric acid, hydrochloric acid and sulfuric acid) and parameters (temperature, controlled pH value, leaching time, and liquid/solid ratio). It was found that hydrochloric acid is relatively efficient in solubilizing copper (68.2±6.3%) and zinc (80.8±5.3%) from the fly ash in less than 24h at 20°C. Efficient leaching of cadmium and lead (over 92% and 90% respectively) was also achieved. Bottom ash from the same combustion unit was also characterized and leached using acid. The metal yields were moderate and the leachates had a tendency to form a gelatinous precipitate, which indicates that the solutions were actually over-saturated with respect to some components. This gel formation will cause problems for further metal purification processes, e.g. solvent extraction. PMID:26463013

  15. Mechanism of electro-generating leaching of chalcopyrite-MnO2 in presence of Acidithiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    XIAO Li; LIU Jian-she; FANG Zheng; QIU Guan-zhou

    2008-01-01

    A dual cell system with chalcopyrite anode and MnO2 cathode was used to study the relations between time and such data as the electric quantity and the dissolution rates of the two minerals in the electro-generating leaching(EGL) and the bio-electro-generating leaching(BEGL),respectively.The results showed that the dissolution rates for Cu2+ and Fe2+ in BEGL were almost 2 times faster than those in EGL,and nearly 3 times for Mn2+; the electric output increased nearly by 3 times.The oxidation residue of chalcopyrite was represented by TEM and XRD,whose pattern was similar to that of the raw ore in EGL.The mechanism for leaching of CuFeS2-MnO2 in the presence of Acidithiobacillus thiooxidans was proposed as a successive reaction of two independent sub-processes for the anode.The first stage,common to both processes,is dissolution of chalcopyrite to produce Cu2+,Fe2+ and sulfur.The second stage is subsequent oxidization of sulfur only in BEGL,which is the controlling step of the process.However,the dissolution of MnO2 lasts until the reaction of chalcopyrite stops or the ores exhaust in two types of leaching.

  16. Leaching optimization of municipal solid waste incineration ash for resource recovery: A case study of Cu, Zn, Pb and Cd.

    Science.gov (United States)

    Tang, Jinfeng; Steenari, Britt-Marie

    2016-02-01

    Ash from municipal solid waste incineration (MSWI) may be quite cumbersome to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as toxic metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of copper, zinc and lead from MSWI ashes, for example, will not only provide valuable metals that would otherwise be landfilled but also give an ash residue with lower concentrations of toxic metals. In this work, fly ash and bottom ash from an MSWI facility was used for the study and optimization of metal leaching using different solutions (nitric acid, hydrochloric acid and sulfuric acid) and parameters (temperature, controlled pH value, leaching time, and liquid/solid ratio). It was found that hydrochloric acid is relatively efficient in solubilizing copper (68.2±6.3%) and zinc (80.8±5.3%) from the fly ash in less than 24h at 20°C. Efficient leaching of cadmium and lead (over 92% and 90% respectively) was also achieved. Bottom ash from the same combustion unit was also characterized and leached using acid. The metal yields were moderate and the leachates had a tendency to form a gelatinous precipitate, which indicates that the solutions were actually over-saturated with respect to some components. This gel formation will cause problems for further metal purification processes, e.g. solvent extraction.

  17. Characteristics and aluminum reuse of textile sludge incineration residues after acidification

    Institute of Scientific and Technical Information of China (English)

    Manhong Huang; Liang Chen; Donghui Chen; Saijie Zhou

    2011-01-01

    The chemical composition and aluminum speciation of sludge incineration residue (SIR) were determined.Cementation of aluminum from sulfuric acid solution using SIR was studied.The results showed that acid-soluble inorganic aluminum was the predominant component in the sludge,and the total leached aluminum increased from 62.2% to 92.9% after incineration.Sulfuric acid dosage and reaction time were found to affect aluminum recovery positively.Conversely,the increase in temperature significantly inhibited recovery reactions.The optimized leaching condition was 1.66 g sulfuric acid per gram of SIR with a reaction time of 3 hr at 20°C,resulting in the highest aluminum leaching rate of 96.7%.Compared to commercial aluminum sulfate solution coagulants,the leaching solution demonstrated higher CODcr,turbidity and color removal efficiency for textile wastewater.

  18. Different strategies for recovering metals from CARON process residue

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, G., E-mail: gema.cabrera@uca.es [Biological and Enzymatic Reactors Group, Department of Chemical Engineering and Food Technology, Faculty of Sciences, University of Cadiz (Spain); Gomez, J.M., E-mail: josemanuel.montesdeoca@uca.es [Biological and Enzymatic Reactors Group, Department of Chemical Engineering and Food Technology, Faculty of Sciences, University of Cadiz (Spain); Hernandez, I., E-mail: ianeyahd@fbio.uh.cu [Laboratory of Metals, Department of Microbiology, Faculty of Biology, University of Havana (Cuba); Coto, O., E-mail: ocoto@fbio.uh.cu [Laboratory of Metals, Department of Microbiology, Faculty of Biology, University of Havana (Cuba); Cantero, D., E-mail: domingo.cantero@uca.es [Biological and Enzymatic Reactors Group, Department of Chemical Engineering and Food Technology, Faculty of Sciences, University of Cadiz (Spain)

    2011-05-30

    The capacity of Acidithiobacillus thiooxidans DMS 11478 to recover the heavy metals contained in the residue obtained from the CARON process has been evaluated. Different bioreactor configurations were studied: a two-stage batch system and two semi-continuous systems (stirred-tank reactor leaching and column leaching). In the two-stage system, 46.8% Co, 36.0% Mg, 26.3% Mn and 22.3% Ni were solubilised after 6 h of contact between the residue and the bacteria-free bioacid. The results obtained with the stirred-tank reactor and the column were similar: 50% of the Mg and Co and 40% of the Mn and Ni were solubilised after thirty one days. The operation in the column reactor allowed the solid-liquid ratio to be increased and the pH to be kept at low values (<1.0). Recirculation of the leachate in the column had a positive effect on metal removal; at sixty five days (optimum time) the solubilisation levels were as follows: 86% Co, 83% Mg, 72% Mn and Ni, 62% Fe and 23% Cr. The results corroborate the feasibility of the systems studied for the leaching of metals from CARON process residue and these methodologies can be considered viable for the recovery of valuable metals.

  19. Bioactive contaminants leach from disposable laboratory plasticware.

    Science.gov (United States)

    McDonald, G Reid; Hudson, Alan L; Dunn, Susan M J; You, Haitao; Baker, Glen B; Whittal, Randy M; Martin, Jonathan W; Jha, Amitabh; Edmondson, Dale E; Holt, Andrew

    2008-11-01

    Disposable plasticware such as test tubes, pipette tips, and multiwell assay or culture plates are used routinely in most biological research laboratories. Manufacturing of plastics requires the inclusion of numerous chemicals to enhance stability, durability, and performance. Some lubricating (slip) agents, exemplified by oleamide, also occur endogenously in humans and are biologically active, and cationic biocides are included to prevent bacterial colonization of the plastic surface. We demonstrate that these manufacturing agents leach from laboratory plasticware into a standard aqueous buffer, dimethyl sulfoxide, and methanol and can have profound effects on proteins and thus on results from bioassays of protein function. These findings have far-reaching implications for the use of disposable plasticware in biological research. PMID:18988846

  20. 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.

  1. The performance with data processing of chemical treatment with leaching and bio-leaching

    OpenAIRE

    Agron, Alili; Krstev, Boris; Krstev, Aleksandar; Stamenov, Goran

    2015-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and excel...

  2. Using applicative software and software tools for the performance of leaching and bio-leaching

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Gocev, Zivko; Zdravev, Zoran; Krstev, Dejan; Zivanovic, Jordan

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  3. The principles and examples of leaching and bio-leaching using SImplex EVOP

    OpenAIRE

    Krstev, Aleksandar; Krstev, Boris

    2014-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms - bioleaching. The paper is result of these technologies and investigations earned out for recovery of in the mentioned ores. Using Simples EVOP and computer program Multisimplex performances are appropriate and most acceptable and excellen...

  4. The presentation of leaching and bio-leaching from different ores using SIMPLEX EVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeova, Mirjana; Gocev, Zivko

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  5. The performance of leaching and bio-leaching from sulphide ores usiing SEVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeov, Blagoj; Golomeova, Mirjana; Sala, Ferat; Gocev, Zivko; Zivanovic, Jordan; Krstev, Dejan

    2013-01-01

    The refractory or low grade copper chalcopyrite ores or galena/sphalerite domestic ores in Republic of Macedonia are investigated by conventional copper flotation and selective flotation for galena/sphalerite. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer programme. Multisimple...

  6. Analysis of residual tritium in an LP 50 product container

    Energy Technology Data Exchange (ETDEWEB)

    Wermer, J.R.

    1996-06-04

    The analysis was done by sampling coupons cut from the side of the vessel. Tests were performed to analyze the amount of residual tritium in the container wall, as well as the amount of tritium removed through exposure to moist air. Based on this data, the PC contained 62 curies of residual tritium. Air exposure and leaching of the coupons in aqua regia accounted for 27 curies. Recommendations are given for final processing of these containers in order to reduce the final tritium content.

  7. Pesticide leaching through sandy and loamy fields e Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Annette Elisabeth; Olsen, Preben; Plauborg, Finn;

    2015-01-01

    The European Union authorization procedure for pesticides includes assessment of the leaching risk posed by pesticides and their degradation products aimed at avoiding any unacceptable influence on the environment, in particular contamination of water, including drinking water and groundwater. The...... procedure has shortcomings, however, as revealed by the past 11years of monitoring results from the Danish Pesticide Leaching Assessment Programme. This monitoring programme have assessed leaching to the groundwater via the variably saturated zone of 43 pesticides applied in accordance with current...... regulations on sandy and loamy agricultural fields, as well as 47 of their degradation products. Three types of leaching scenario were not fully captured by the authorization procedure: i) long-term leaching of degradation products of pesticides applied to potatoes crops cultivated on sandy soils; ii...

  8. Immobilization of Rocky Flats graphite fines residues

    International Nuclear Information System (INIS)

    The Savannah River Technology Center (SRTC) is developing an immobilization process for graphite fines residues generated during nuclear materials production activities at the Rocky Flats Environmental Technology Site (Rocky Flats). The continued storage of this material has been identified as an item of concern. The residue was generated during the cleaning of graphite casting molds and potentially contains reactive plutonium metal. The average residue composition is 73 wt% graphite, 15 wt% calcium fluoride (CaF2), and 12 wt% plutonium oxide (PuO2). Approximately 950 kg of this material are currently stored at Rocky Flats. The strategy of the immobilization process is to microencapsulate the residue by mixing with a sodium borosilicate (NBS) glass frit and heating at nominally 700 C. The resulting waste form would be sent to the Waste Isolation Pilot Plant (WIPP) for disposal. Since the PuO2 concentration in the residue averages 12 wt%, the immobilization process was required to meet the intent of safeguards termination criteria by limiting plutonium recoverability based on a test developed by Rocky Flats. The test required a plutonium recovery of less than 4 g/kg of waste form when a sample was leached using a nitric acid/CaF2 dissolution flowsheet. Immobilization experiments were performed using simulated graphite fines with cerium oxide (CeO2) as a surrogate for PuO2 and with actual graphite fines residues. Small-scale surrogate experiments demonstrated that a 4:1 frit to residue ratio was adequate to prevent recovery of greater than 4 g/kg of cerium from simulated waste forms. Additional experiments investigated the impact of varying concentrations of CaF2 and the temperature/heating time cycle on the cerium recovery. Optimal processing conditions developed during these experiments were subsequently demonstrated at full-scale with surrogate materials and on a smaller scale using actual graphite fines

  9. Leaching of Natural Gravel and Concrete by CO2 - Experimental Design, Leaching Behaviour and Dissolution Rates

    Science.gov (United States)

    Fuchs, Rita; Leis, Albrecht; Mittermayr, Florian; Harer, Gerhard; Wagner, Hanns; Reichl, Peter; Dietzel, Martin

    2015-04-01

    The durability of building material in aggressive aqueous environments is a key factor for evaluating the product quality and application as well as of high economic interest. Therefore, aspects of durability have been frequently investigated with different approaches such as monitoring, modelling and experimental work. In the present study an experimental approach based on leaching behaviour of natural calcite-containing siliceous gravel used as backfill material in tunnelling and sprayed concrete by CO2 was developed. CO2 was introduced to form carbonic acid, which is known as an important agent to induce chemical attack. The goals of this study were (i) to develop a proper experimental design to survey the leaching of building materials on-line, (ii) to decipher individual reaction mechanisms and kinetics and (iii) to estimate time-resolved chemical resistance of the used material throughout leaching. A combined flow through reactor unit was successfully installed, where both open and closed system conditions can be easily simulated by changing flow directions and rates. The chemical compositions of the experimental solutions were adjusted by CO2 addition at pHstat conditions and monitored in-situ by pH/SpC electrodes and by analysing the chemical composition of samples throughout an experimental run. From the obtained data e.g. dissolution rates with respect to calcite were obtained for the gravel material, which were dependent on the individual calcite content of the leached material. The rates were found to reflect the flow rate conditions, and the kinetic data lay within the range expected from dissolution experiments in the CaCO3-CO2-H2O system. In case of concrete the reactions throughout the leaching experiment were complex. Coupled dissolution and precipitation phenomena (e.g. portlandite dissolution, calcite formation) occurred. The coupled reactions can be followed by the evolution of the solution chemistry. The overall rates of elemental removal from

  10. The fate of nitrogen from crop residues of broccoli, leek and sugar beet

    OpenAIRE

    Ruijter, de, F.J.; Berge, ten, M.; Smit, A.L.

    2010-01-01

    Environmental concern has lead to legislation on fertilization to reduce nutrient losses to the environment. Reducing N input may be inadequate for crops that have a high N content in their residues. Reducing N input will negatively affect yield, but the residues remain. Management of crop residues may then be a more effective strategy to reduce N losses, notably nitrate leaching. Two experiments were carried out in 2006-07 and 2007-08 to study all emission routes of N from crop residues of b...

  11. 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.

  12. Accelerating column leaching trial on copper sulfide ore

    Institute of Scientific and Technical Information of China (English)

    WANG Hongjiang; WU Aixiang; ZHOU Xun; WANG Shaoyong; ZHANG Jie

    2008-01-01

    The main measures to accelerate leaching sulfide ore are large spraying intensity,manual oxygen supply,temperature control and acclimated bacteria.The indoor experiment accelerating sulfide ore leaching detected the temperature during leaching process,dissolvability of oxygen,bacterial concentration,Cu concentration and slag grade.At the same time,this paper also analyzed the effect of four factors,which are bacterial diversity cultivation stage,spraying intensity,air supply,and whether to control temperature,on the leaching efficiency of copper.The results indicate that the oxygen content of leach solution has a close relationship with temperature but it is rarely affected by air supply.The bacterial concentration preserves from 106 to 107 mL-1,and temperature has a great effect on the bacterial activity under the condition of proper temperature and oxygen supply,and the lack of nutrition prevents the bacterial concentration from rising in the late stage.The relationships of the copper leaching efficiency to temperature,air feed,and spraying intensity are directly proportional.The leaching efficiencies of the cultivated bacteria and acclimation bacteria are 1.2 and 1.4 times as large as that of the original bacteria.

  13. Complex Leaching Process of Scheelite in Hydrochloric and Phosphoric Solutions

    Science.gov (United States)

    Liu, Liang; Xue, Jilai; Liu, Kang; Zhu, Jun; Wang, Zengjie

    2016-09-01

    The complex leaching process of synthetic scheelite and scheelite concentrate in hydrochloric and phosphoric solutions has been investigated for improving process efficiency. A higher leaching rate, compared with the classic acid leaching process, can be obtained through the synergy of HCl and H3PO4 with appropriate W/P mole ratio, temperature, and acid concentration. For synthetic scheelite, the optimum leaching conditions were W/P mole ratio 7:1, temperature 50°C, HCl 0.72 mol/L, and stirring speed 600 rpm; for scheelite concentrate, W/P mole ratio 7:1, temperature 80°C, HCl 2.16 mol/L, and stirring speed 1000 rpm. The leaching rates under the optimized conditions can reach up to 98% or even higher. FTIR spectra analysis confirmed that the leachate composition remained as H3[PW12O40] in the range of varying W/P mole ratios, so the PO4 3- in acidic solution and phosphorus content in the leaching product could be better controlled. The function 1 - (1 - X)1/3 against leaching time was applied to fit the experimental data, and the apparent activation energy, E a, was calculated as 60.65 kJ/mol. The results would be valuable for effectively using scheelite as a raw material resource for sustainable tungsten production.

  14. Dynamics of aluminum leaching from water purification sludge.

    Science.gov (United States)

    Cheng, Wen-Po; Fu, Chi-Hua; Chen, Ping-Hung; Yu, Ruey-Fang

    2012-05-30

    In this investigation, the shrinking core model is used to study the rate of aluminum salt leaching from water purification sludge (WPS). This model, which describes the aluminum leaching rate, can be developed to maximize the Al(III) recovering efficiency. Laboratory results indicate that when the mixing speed exceeds 80rpm, the effect of film diffusion control on the leaching process is greatly reduced, such that any further increase in the mixing speed does not affect the Al(III) leaching rate. Additionally, increasing the temperature or acid concentration improves Al(III) leaching rate. The laboratory data were verified by using the shrinking core model to confirm that the leaching of Al(III) from WPS is consistent with the inert-layer diffusion control model. This finding reveals that large amounts of SiO(2), Al(2)O(3) and other inert constituents will form an inter diffusion layer in the WPS and thus become the major limiting factors that control the Al(III) leaching process. The dynamic equation can be expressed as 1-3(1-x)(2/3)+2(1-x)=(2707.3 exp(-3887.6/T))t, in which the apparent activation energy and pre-exponential factors are 32.32 kJ/mol and 2707.3 min(-1), respectively, as determined by solving the Arrhenius equation.

  15. Defense High-Level Waste Leaching Mechanisms Program. Final report

    International Nuclear Information System (INIS)

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 900C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations

  16. Analysis of SPR salt cavern remedial leach program 2013.

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Paula D.; Gutierrez, Karen A.; Lord, David L.; Rudeen, David Keith

    2013-09-01

    The storage caverns of the US Strategic Petroleum Reserve (SPR) exhibit creep behavior resulting in reduction of storage capacity over time. Maintenance of oil storage capacity requires periodic controlled leaching named remedial leach. The 30 MMB sale in summer 2011 provided space available to facilitate leaching operations. The objective of this report is to present the results and analyses of remedial leach activity at the SPR following the 2011 sale until mid-January 2013. This report focuses on caverns BH101, BH104, WH105 and WH106. Three of the four hanging strings were damaged resulting in deviations from normal leach patterns; however, the deviations did not affect the immediate geomechanical stability of the caverns. Significant leaching occurred in the toes of the caverns likely decreasing the number of available drawdowns until P/D ratio criteria are met. SANSMIC shows good agreement with sonar data and reasonably predicted the location and size of the enhanced leaching region resulting from string breakage.

  17. Advances in Nitrogen Loss Leached by Precipitation from Plant Canopy

    Institute of Scientific and Technical Information of China (English)

    LI Shi-qing; JI Chun-rong; FANG Ya-ning; CHEN Xiao-li; LI Sheng-xiu

    2008-01-01

    Function of canopy in changing nutrient cycle and flux is one of the focuses in recent years. On the basis of comprehensively appraising published research, we analyzed the nitrogen loss leaching from plant canopy and several factors which affected it. We pointed out the disadvantages of the published researches and the key issues that ought to be solved: (1) The menstruation need to be advanced, and the research should be carried out on nitrogen loss leaching from the canopy of the field plant. (2) If the nitrogen is leached from the plant canopy, the research on the type of nitrogen loss should be carried out, and the nitrogen use efficiency of different varieties should be dealt on a research perspective with regard to the nitrogen leaching. (3) The research should be conducted on the mechanism and pathway, and the progress of nitrogen leaching; and the factors affecting nitrogen leaching should be included in the research, such as the leaf area of different growth stages, stomata densities, stomata conductance, and the apparent free space, which are beneficial to explain the mechanism of nitrogen leaching from the plant canopy.

  18. Defense High-Level Waste Leaching Mechanisms Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mendel, J.E. (compiler)

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  19. The status of atmospheric direct leaching technology of zinc sulphide concentrate%硫化锌精矿常压直接浸出技术现状

    Institute of Scientific and Technical Information of China (English)

    邱定蕃; 徐志峰

    2013-01-01

    Based on the comprehensive summary of direct leaching technology of zinc sulphide concentrate both domestic and overseas, the principles, technical processes as well as equipments of atmospheric direct leaching (ADL) technology are reviewed. It is further proposed that ADL technology is the optimization for the reform of exiting zinc production system, plant expansion and recycling of the leaching residue.%  在广泛收集整理国内外硫化锌精矿直接浸出技术资料的基础上,对常压直接浸出技术原理、工艺过程及设备进行了介绍和评述,指出常压直接浸出技术是现有锌系统技术改造、实现扩产及锌浸出渣资源循环利用的优选方案之一。

  20. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.