Sample records for yellow phosphorus slag


    Y.Z. Lan; S. Zhang; J.K. Wang; R. W. Smith


    Steel slag is a byproduct produced in large amounts in the steel-making process. It is an important resource that can be effectively utilized. An experiment was described in which steel slag was tested as an adsorbent for the removal of phosphorus from waste water. Phosphorus removal depended on the amount of steel slag added, the pH value, the contact time, and the initial concentration. Under laboratory conditions when the added slag was 7.5g/L, the contact time 2h, and the pH value was equivalent to 6.5, over 99% of the phosphorus was removed; the experimental data on steel slag adsorption of phosphorus in the water fitted the Freundlich isotherm model. Steel slag was found to be very effective in adsorbing phosphorus.

  2. Effect of Fe2O3 on the crystallization behavior of glass-ceramics produced from naturally cooled yellow phosphorus furnace slag

    Liu, Hong-pan; Huang, Xiao-feng; Ma, Li-ping; Chen, Dan-li; Shang, Zhi-biao; Jiang, Ming


    CaO-Al2O3-SiO2 (CAS) glass-ceramics were prepared via a melting method using naturally cooled yellow phosphorus furnace slag as the main raw material. The effects of the addition of Fe2O3 on the crystallization behavior and properties of the prepared glass-ceramics were studied by differential thermal analysis, X-ray diffraction, and scanning electron microscopy. The crystallization activation energy was calculated using the modified Johnson-Mehl-Avrami equation. The results show that the intrinsic nucleating agent in the yellow phosphorus furnace slag could effectively promote the crystallization of CAS. The crystallization activation energy first increased and then decreased with increasing amount of added Fe2O3. At 4wt% of added Fe2O3, the crystallization activation energy reached a maximum of 676.374 kJ·mol-1. The type of the main crystalline phase did not change with the amount of added Fe2O3. The primary and secondary crystalline phases were identified as wollastonite (CaSiO3) and hedenbergite (CaFe(Si2O6)), respectively.

  3. 黄磷炉渣废热利用新工艺与实验研究%New processes and experimental study on yellow phosphorus slag of waste heat utilization

    马立; 魏代晓; 龙恩深; 田向伟


    The need for waste heat recovery from molten yellow phosphorus slag is analyzed. The difficulties of yellow phosphorus slag heat recovery are explained in detail. Based on the field investigation, thermal analysis and experimental research,a new designing scheme of slag heat recovering and reuse system in yellow phosphorus slag is provided. The system structure and gain of energy-saving and environmental protection of slag waste heat recovery kiln are introduced and proved.%分析了黄磷炉渣废热回收利用的必要性,详细阐述了黄磷炉渣热回收存在的难点,通过现场调研、热工分析及试验研究,提出了利用炉渣废热回收窑对黄磷炉渣废热进行回收与再利用的新工艺,介绍了该工艺的系统结构,验证了该工艺的节能减排效果.

  4. 49 CFR 173.188 - White or yellow phosphorus.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for... pound) of phosphorus with screw-top closures; or (2) Steel drums (1A1) not over 250 L (66...

  5. Distribution of Phosphorus between CaO-CaF2 Slag and Fe-C-P Melt

    WANG Qing-xiang; ZHOU Jian-jian; DU Xiao-jian


    The equilibrium distribution ratio of phosphorus between CaO-CaF2 molten slag and Fe-C-P melt at 1450 ℃ was measured. The phosphate capacity of slag and the activity coefficient of phosphorus oxide were calculated.

  6. Processing of Phosphorus Slag with Recovery of Rare Earth Metals and Obtaining Silicon Containing Cake

    Karshigina, Zaure; Abisheva, Zinesh; Bochevskaya, Yelena; Akcil, Ata; Sharipova, Aynash; Sargelova, Elmira


    The present research is devoted to the processing of slag generating during the yellow phosphorus production. In this paper are presented studies on leaching of phosphorus production slag by nitric acid with recovery of rare earth metals (REMs) into solution. REMs recovery into the solution achieved 98 % during the leaching process with using 7.5 mol/L of HNO3, liquid-to-solid ratio is 2.6:1, temperature is 60°C, process duration is 1 hour and stirrer speed is 500 rpm. Behaviour during the leaching of associated components such as calcium, aluminium, and iron was studied. After the leaching cake contains ∼⃒75-85 % of SiO2 and it might be useful for obtaining of precipitated silicon dioxide. With the purpose of separation from the impurities, recovery and concentrating of REMs, the obtained solution after leaching was subjected to extraction processing methods. The influence of ratio of organic and aqueous phases (O: A) on the extraction of rare earth metals by tributyl phosphate (TBP) with concentrations from 20 up to 100 % was studied. The REMs extraction with increasing TBP concentration under changes O:A ratio from 1:20 down to 1:1 into the organic phase from the solutions after nitric acid leaching increased from 22.2 up to 99.3%. The duration effect of REMs extraction process was studied by tributyl phosphate. It is revealed that with increasing of duration of the extraction process from 10 to 30 minutes REMs recovery into the organic phase almost did not changed. The behaviour of iron in the extraction process by TBP was studied. It was found that such accompanying components as calcium and aluminium by tributyl phosphate didn't extracted. To construct isotherm of REMs extraction of by tributyl phosphate was used variable volume method. It was calculated three-step extraction is needed for REMs recovery from the solutions after nitric acid leaching of phosphorus production slag. The process of the three-steps counter current extraction of rare earth

  7. Removal kinetics of phosphorus from synthetic wastewater using basic oxygen furnace slag.

    Han, Chong; Wang, Zhen; Yang, He; Xue, Xiangxin


    Removal kinetics of phosphorus through use of basic oxygen furnace slag (BOF-slag) was investigated through batch experiments. Effects of several parameters such as initial phosphorus concentration, temperature, BOF-slag size, initial pH, and BOF-slag dosage on phosphorus removal kinetics were measured in detail. It was demonstrated that the removal process of phosphorus through BOF-slag followed pseudo-first-order reaction kinetics. The apparent rate constant (kobs) significantly decreased with increasing initial phosphorus concentration, BOF-slag size, and initial pH, whereas it exhibited an opposite trend with increasing reaction temperature and BOF-slag dosage. A linear dependence of kobs on total removed phosphorus (TRP) was established with kobs=(3.51±0.11)×10(-4)×TRP. Finally, it was suggested that the Langmuir-Rideal (L-R) or Langmuir-Hinshelwood (L-H) mechanism may be used to describe the removal process of phosphorus using BOF-slag.

  8. Ups and Downs of the Yellow Phosphorus Market in 2007


    @@ 1 Surplus capacity The rapid growth of the economy in China promoted drastic development of the yellow phosphorus sector from 1985 to 2004. The capacity of yellow phosphorus expanded rapidly from 100 000 t/a in 1985 to 1.2 million t/a in 2004 with an average annual growth of around 14.0%.

  9. Phosphorus partitioning and recovery of low-phosphorus iron-rich compounds through physical separation of Linz-Donawitz slag

    Makhija, Dilip; Rath, Rajendra Kumar; Chakravarty, Kaushik; Patra, Abhay Shankar; Mukherjee, Asim Kumar; Dubey, Akhilesh Kumar


    The Linz-Donawitz (LD) steelmaking process produces LD slag at a rate of about 125 kg/t. After metallic scrap recovery, the non-metallic LD slag is rejected because its physical/chemical properties are unsuitable for recycling. X-ray diffraction (XRD) studies have indicated that non-metallic LD slag contains a substantial quantity of mineral phases such as di- and tricalcium silicates. The availability of these mineral phases indicates that LD slag can be recycled by iron (Fe)-ore sintering. However, the presence of 1.2wt% phosphorus (P) in the slag renders the material unsuitable for sintering operations. Electron probe microscopic analysis (EPMA) studies indicated concentration of phosphorus in dicalcium silicate phase as calcium phosphate. The Fe-bearing phases (i.e., wustite and dicalcium ferrite) showed comparatively lower concentrations of P compared with other phases in the slag. Attempts were made to lower the P content of LD slag by adopting various beneficiation techniques. Dry high-intensity magnetic separation and jigging were performed on as-received samples with particle sizes of 6 and 3 mm. Spiral separation was conducted using samples ground to sizes of less than 1 and 0.5 mm. Among these studies, grinding to 0.5 mm followed by spiral concentration demonstrated the best results, yielding a concentrate with about 0.75wt% P and 45wt% Fe.

  10. Heavy metal adsorption changes of EAF steel slag after phosphorus adsorption.

    Song, Guanling; Cao, Lijing; Chen, Xiao; Hou, Wenhua; Wang, Qunhui


    A kind of electric arc furnace (EAF) steel slag was phosphated, and its isothermal and dynamic adsorptions of copper, cadmium, and lead ions were measured to determine if heavy metal adsorption changes after phosphorus adsorption. The surface area increased greatly after the slag was phosphated. Isothermal adsorption experiments showed that the theoretical Q(max) of the EAF steel slag on Cu(2+), Cd(2+), and Pb(2+) improved 59, 50, and 89% respectively after it was phosphated. Dynamic adsorption results showed that the greatest adsorption capacities of unit volume of Cu(2+), Cd(2+), and Pb(2+) were 2.2, 1.8, and 1.8 times that of the column packed with original EAF steel slag when the column was packed with phosphate EAF steel slag at the same heavy metal ion concentration. The breakthrough time, the exhaustion time and elution efficiency of the column also increased when the column was packed with phosphated EAF steel slag compared with that packed with original EAF steel slag. Phosphorus adsorption could further improve the heavy metal ion adsorption of the EAF steel slag.

  11. Model of phosphorus precipitation and crystal formation in electric arc furnace steel slag filters.

    Claveau-Mallet, Dominique; Wallace, Scott; Comeau, Yves


    The objective of this study was to develop a phosphorus retention mechanisms model based on precipitation and crystallization in electric arc furnace slag filters. Three slag columns were fed during 30 to 630 days with a reconstituted mining effluent at different void hydraulic retention times. Precipitates formed in columns were characterized by X-ray diffraction and transmission electronic microscopy. The proposed model is expressed in the following steps: (1) the rate limiting dissolution of slag is represented by the dissolution of CaO, (2) a high pH in the slag filter results in phosphorus precipitation and crystal growth, (3) crystal retention takes place by filtration, settling and growth densification, (4) the decrease in available reaction volume is caused by crystal and other particulate matter accumulation (and decrease in available reaction time), and (5) the pH decreases in the filter over time if the reaction time is too low (which results in a reduced removal efficiency). Crystal organization in a slag filter determines its phosphorus retention capacity. Supersaturation and water velocity affect crystal organization. A compact crystal organization enhances the phosphorus retention capacity of the filter. A new approach to define filter performance is proposed: saturation retention capacity is expressed in units of mg P/mL voids.

  12. Investigations on phosphorus recovery and reuse as soil amendment from electric arc furnace slag filters.

    Bird, Simon C; Drizo, Aleksandra


    Electric arc furnace (EAF) steel slag has been identified as an effective filter material for the removal of phosphorus (P) from both point and non-point sources. To determine the feasibility of land-applying P saturated EAF steel slag this study was undertaken to investigate (i) saturated EAF steel slag material's potential as a P fertilizer or soil amendment and (ii) P desorption and metals leachate from saturated EAF steel slag material to surface runoff. Medicago sativa (alfalfa) was planted in a nutrient depleted washed sand media. Phosphorus was added either as saturated EAF steel slag or as a standard commercial phosphate fertilizer in order to assess the plant availability of the P from saturated EAF steel slag. Four different P application levels were tested: a low (20 lbs acre furrow slice(-1) (5.5 g P m(-3))) two medium (40 and 60 lbs. acre f.s.(-1) (11 and 16.5 g P m(-3))) and a high (120 lbs. acre f.s.(-1) (33 g P m(-3))). The above-ground biomass of half of the plants was harvested after 5 weeks and the second half at 10 weeks. All treatments regardless of the P source used showed high rates of germination. At the first harvest period (5 weeks) significantly higher above-ground biomass (p < 0.01) was seen at the 3 highest P amendment rates in treatments with triple super phosphate fertilizer (TSP) than with EAF steel slag. However, by the second harvest (10 weeks) only the highest amendment rate of TSP showed a significantly higher amount of biomass (p < 0.01), suggesting that EAF steel slag might be an effective slow release P source. In a second experiment, a rain simulator was used to assess desorption of DRP, TP and metals from a saturated and semi-saturated EAF steel slag. The results revealed that the total amounts of DRP and TP released to surface runoff from EAF steel slag were negligible when compared to the total quantities of P retained by this material. Overall the results from this study demonstrated that once the EAF steel slag filter

  13. Effect of MgO and MnO on Phosphorus Utilization in P-Bearing Steelmaking Slag

    Lin, Lu; Bao, Yan-Ping; Wang, Min; Li, Xiang


    In order to recycle the phosphorus in P-bearing converter slag and make it used as slag phosphate fertilizer, the effect of MgO and MnO in P-bearing steelmaking slag on phosphorus existence form, P2O5 solubility and magnetic separation behavior were researched systematically. The results show that the phosphorus in slag is mainly in the form of n2CaO · SiO2-3CaO · P2O5 (for short nC2S-C3P) solid solution in the P-rich phase for CaO-SiO2-FetO-P2O5-X (X stands for MgO and MnO, respectively). And the increasing of MgO and MnO content has no influence on precipitation of nC2S-C3P solid solution in slag, MnO and MgO mainly enter into RO phase and base phase to form MnFe2O4 and MgFe2O4, which has little effect on the P2O5 content of P-rich phase, so which has little effect on the degree of phosphorus enrichment and phosphorus occurrence form of the P-bearing slag. And adding MgO and MnO into CaO-SiO2-P2O5-Fe2O3 slag system can break the complex net structure formed by Si-O on certain degree, and also hinder the precipitation of β-Ca3(PO4)2 crystal with low citric acid solubility during the melting-cooling process. Therefore, adding appropriate MgO and MnO content into slag can improve the slag P2O5 solubility, but the effect of different amounts of MgO and MnO on the P2O5 solubility has little difference. Meanwhile, adding MgO and MnO into slag can improve the metallization of slag and magnetism of iron-rich phase, make the magnetic substances content increase and separation of phosphorus and iron incomplete, so it is adverse to phosphorus resources recovery from P-bearing slag by magnetic separation method. In order to recycle the phosphorus in P-bearing converter slag, the MgO and MnO content in the P-bearing slag should be controlled in the steelmaking process.

  14. Phosphorus removal by steel slag filters: modeling dissolution and precipitation kinetics to predict longevity.

    Claveau-Mallet, Dominique; Courcelles, Benoît; Comeau, Yves


    This article presents an original numerical model suitable for longevity prediction of alkaline steel slag filters used for phosphorus removal. The model includes kinetic rates for slag dissolution, hydroxyapatite and monetite precipitation and for the transformation of monetite into hydroxyapatite. The model includes equations for slag exhaustion. Short-term batch tests using slag and continuous pH monitoring were conducted. The model parameters were calibrated on these batch tests and experimental results were correctly reproduced. The model was then transposed to long-term continuous flow simulations using the software PHREEQC. Column simulations were run to test the effect of influent P concentration, influent inorganic C concentration and void hydraulic retention time on filter longevity and P retention capacity. High influent concentration of P and inorganic C, and low hydraulic retention time of voids reduced the filter longevity. The model provided realistic P breakthrough at the column outlet. Results were comparable to previous column experiments with the same slag regarding longevity and P retention capacity. A filter design methodology based on a simple batch test and numerical simulations is proposed.

  15. Phosphorus retention capacity of iron-ore and blast furnace slag in subsurface flow constructed wetlands.

    Grüneberg, B; Kern, J


    The suitability of iron-ore and blast furnace slag for subsurface flow (SSF) constructed wetlands was studied over a period of four months. Dairy farm wastewater (TP 45 mg l(-1)) was percolated through buckets planted with reed (volume 9.1 l; hydraulic load 151 m(-2) d(-1)). One group of buckets was kept under aerobic conditions and the other group under anaerobic conditions, monitored by continuous redox potential measurements. Even at high mass loading rates of 0.65 g P m(-1) d(-1) the slag provided 98% removal efficiency and showed no decrease in performance with time. However, phosphorus fractionation data indicate that the high phosphorus retention capacity under aerobic conditions is to a great extent attributable to unstable sorption onto calcium compounds (NH4Cl-P). Phosphorus sorption of both the slag (200 microg P g(-1)) and the iron-ore (140 microg P g(-1)) was promoted by predominantly anaerobic conditions due to continuous formation of amorphous ferrous hydroxides. None of the substrates had adverse affects on reed growth.

  16. Distribution and Changes of Specification of Phosphorus in the Yellow Sea

    Chen Hongtao; Chen Shuzhu; Zhang Jing; Liu Sumei; Wu Qiangming


    The studies on the distribution and varatiation of the specification of phosphorus in the southern part of the Yellow Sea are made. The biogeochemistry of phosphorus in the Yellow Sea is discussed. The phosphorus is slightly higher in the bottom than in the surface waters in the southern part of the Yellow Sea and the dissolved organic phosphorus is the main form. The transfer patterns between various forms of particulate and dissolved phosphorus are different in the bottom and surface, probably due to the contribution of dissolved organic phosphorus. The distributions of dissolved inorganic phosphorus and dissolved organic phosphorus are mainly affected by the biological processes and could act as a prediction factor for the red tide. The supply of N and P in most of the areas in the southern part of the Yellow Sea is sufficient, without apparent limitation of N or P.

  17. Upgrading constructed wetlands phosphorus reduction from a dairy effluent using electric arc furnace steel slag filters.

    Weber, D; Drizo, A; Twohig, E; Bird, S; Ross, D


    In 2003, a subsurface flow constructed wetlands (SSF-CW) system was built at the University of Vermont (UVM) Paul Miller Dairy Farm as an alternative nutrient management approach for treating barnyard runoff and milk parlour waste. Given the increasing problem of phosphorus (P) pollution in the Lake Champlain region, a slag based P-removal filter technology (PFT) was established (2004) at the CW with two objectives: (i) to test the filters' efficiency as an upgrade unit for improving P removal performance via SSF-CW (ii) to investigate the capacity of filters technology to remove P as a "stand alone" unit. Six individual filters (F1-F6) were filled with electric arc furnace (EAF) steel slag, each containing 112.5 kg of material with a pore volume of 21 L. F1-F4, fed with CW treated water, received approximately 2.17 g DRP kg(-1) EAF steel slag (0.25 kg DRP total) during the 259 day feeding period. F1-F4 retained 1.7 g DRP kg(-1) EAF steel slag, resulting in an average P removal efficiency of 75%. The addition of filters improved CW DRP removal efficiency by 74%. F5 and F6, fed non-treated water, received 1.9 g DRP kg(-1) EAF steel slag (0.22 kg DRP in total) and retained 1.5 g DRP kg(-1) resulting in a P removal efficiency of 72%. The establishment of the EAF slag based PFT is the first in-field evaluation of this technology to reduce P from dairy farm effluent in Vermont.




    Full Text Available In this study, metakaolin plus different weight percent of phosphorus slag (10-100 wt. % were used in preparation of geopolymer. The compressive strength, phase analysis and microstructure changes were compared with a metakaolin based geopolymer control sample. Results showed that the substitution of slag up to 40 wt. % instead of metakaolin increase the 28 days compressive strength (14.5 % compared with control sample. This enhancement of strength is related to coexistence of geopolymeric gel and C‒S‒H gel or C‒A‒S‒H phase by XRD and FTIR study. In slag containing geopolymer samples some microcracks were observed at microstructure that established by volume change during formation of new phase or mismatching of unreacted particle with geopolymeric gel. These microcrack can dominate at high content of slag (above 40 wt. % substitution and decrease the strength of samples. These results show that it is possible to produce geopolymer cement from waste phosphorus slages.

  19. Comparative research on phosphorus removal by pilot-scale vertical flow constructed wetlands using steel slag and modified steel slag as substrates.

    Yun, Yupan; Zhou, Xiaoqin; Li, Zifu; Uddin, Sayed Mohammad Nazim; Bai, Xiaofeng


    This research mainly focused on the phosphorus removal performance of pilot-scale vertical flow constructed wetlands with steel slag (SS) and modified steel slag (MSS). First, bench-scale experiments were conducted to evaluate the phosphorus adsorption capacity. Results showed that the Langmuir model could better describe the adsorption characteristics of the two materials; the maximum adsorption of MSS reached 12.7 mg/g, increasing by 34% compared to SS (9.5 mg/g). Moreover, pilot-scale constructed wetlands with SS and MSS were set up outdoors. Then, the influence of hydraulic retention time (HRT) and phosphorus concentration in phosphorus removal for two wetlands were investigated. Results revealed that better performance of the two systems could be achieved with an HRT of 2 d and phosphorus concentration in the range of 3-4.5 mg/L; the system with MSS had a better removal efficiency than the one with SS in the same control operation. Finally, the study implied that MSS could be used as a promising substrate for wetlands to treat wastewater with a high phosphorus concentration. However, considering energy consumption, SS could be regarded as a better alternative for substrate when treating sewage with a low phosphorus concentration.

  20. [Phosphorus adsorption and regeneration of electric arc furnace steel slag as wetland medium].

    Zhai, Li-hua; He, Lian-sheng; Xi, Bei-dou; Chen, Yue; Meng, Rui; Huo, Shou-liang; Liu, Hong-liang


    The long-term phosphorus (P) adsorption and retention capacities of electric arc furnace (EAF) steel slag materials derived from one batch and a 278-d column experiments with a synthetic P solution were compared. The investigations of the regeneration of the P adsorption capacity by water level decrease was conducted. It was revealed column experiment on a long-term basis can determine P saturation of EAF accurately. And the results can be used for realistic estimations of constructed wetland systems (CWS) longevity. EAF slag showed a high afinity for P, reaching a saturation value of 1.65 g/kg. Regeneration experiment of the P adsorbing capacity by this material showed that, after 4 weeks of water level decrease, EAF steel slag was able to increase its initial P adsorption capacity to 2.65 g/kg. A sequential P fractionation experiment was performed to quantify the proportion of P bound to mineral compounds in EAF. From the most loosely bound to the most strongly bound P fraction, P1 was associated with resin extractable (13%), Fe extractable (0.5 mol/L Na2CO3, 39%), Al extractable (0.1 mol/L NaOH, 21%), Ca extractable (1 mol/L HCl, 13%), and Ca in a stable residual pool (concentrated hot HCl, 14%). X-ray fluorescence analyses of EAF steel slag chemical composition revealed that the continuous application of a P solution resulted in 300% and 170% increases in K2O and P2O5, respectively. Al2O3 and FeO increased by 8%, while the portion of CaO remained unchanged. The investigated properties (P retention potential, regeneration of P adsorption, P fractionation) provide useful data about the suitability of slag material as a media for longterm P removal and dry-wet operation can improve P retention capacity of EAF to prolong the longevity of full-scale CWS.

  1. Active slag filters-simple and sustainable phosphorus removal from wastewater using steel industry byproduct.

    Pratt, C; Shilton, A


    Active filtration, where effluent is passed through a reactive substrate such as steel slag, offers a simple and cost-effective option for removing phosphorus (P) from effluent. This work summarises a series of studies that focused on the world's only full-scale active slag filter operated through to exhaustion. The filter achieved 75% P-removal during its first 5 years, reaching a retention capacity of 1.23 g P/kg slag but then its performance sharply declined. Scanning electron microscopy, X-ray diffraction, X-ray fluorescence, and chemical extractions revealed that P sequestration was primarily achieved via adsorption onto iron (Fe) oxyhydroxides on the slag's surface. It was concluded that batch equilibrium tests, whose use has been repeatedly proposed in the literature, cannot be used as an accurate predictor of filter adsorption capacity because Fe oxyhydroxides form via chemical weathering in the field, and laboratory tests don't account for this. Research into how chemical conditions affect slag's P retention capacity demonstrated that near-neutral pH and high redox are optimal for Fe oxyhydroxide stability and overall filter performance. However, as Fe oxyhydroxide sites fill up, removal capacity becomes exhausted. Attempts to regenerate P removal efficiency using physical techniques proved ineffective contrary to dogma in the literature. Based on the newly-developed understanding of the mechanisms of P removal, chemical regeneration techniques were investigated and were shown to strip large quantities of P from filter adsorption sites leading to a regenerated P removal efficiency. This raises the prospect of developing a breakthrough technology that can repeatedly remove and recover P from effluent.

  2. Removal of phosphorus, fluoride and metals from a gypsum mining leachate using steel slag filters.

    Claveau-Mallet, Dominique; Wallace, Scott; Comeau, Yves


    The objective of this work was to evaluate the capacity of steel slag filters to treat a gypsum mining leachate containing 11-107 mg P/L ortho-phosphates, 9-37 mg/L fluoride, 0.24-0.83 mg/L manganese, 0.20-3.3 zinc and 1.7-8.2 mg/L aluminum. Column tests fed with reconstituted leachates were conducted for 145-222 days and sampled twice a week. Two types of electric arc furnace (EAF) slags and three filter sequences were tested. The voids hydraulic retention time (HRT(v)) of columns ranged between 4.3 and 19.2 h. Precipitates of contaminants present in columns were sampled and analyzed with X-ray diffraction at the end of tests. The best removal efficiencies over a period of 179 days were obtained with sequential filters that were composed of Fort Smith EAF slag operated at a total HRT(v) of 34 h which removed 99.9% of phosphorus, 85.3% of fluoride, 98.0% of manganese and 99.3% of zinc. Mean concentration at this system's effluent was 0.04 mg P/L ortho-phosphates, 4 mg/L fluoride, 0.02 mg/L manganese, 0.02 zinc and 0.5 mg/L aluminum. Thus, slag filters are promising passive and economical systems for the remediation of mining effluents. Phosphorus was removed by the formation of apatite (hydroxyapatite, Ca(5)(PO(4))(3)OH or fluoroapatite, Ca(5)(PO(4))(3)F) as confirmed by visual and X-ray diffraction analyses. The growth rate of apatite was favored by a high phosphorus concentration. Calcite crystals were present in columns and appeared to be competing for calcium and volume needed for apatite formation. The calcite crystal growth rate was higher than that of apatite crystals. Fluoride was removed by precipitation of fluoroapatite and its removal was favored by a high ratio of phosphorus to fluoride in the wastewater.

  3. The Effect of Slag on the Effectiveness of Phosphorus Removal from Ferrous Alloys Containing Carbon, Chromium and Nickel

    Kawecka-Cebula E.


    Full Text Available The aim of this study was to determine the impact of slag composition on phosphorus removal from ferrous solutions containing carbon, chromium and nickel. Additions of cryolite, Na3AlF6, were applied for better fluxing and higher phosphate capacity of the slag. An X-ray analysis of final slags formed during dephosphorization of ferrous solutions containing chromium and nickel with CaO-CaF2 or CaO-CaF2-Na3AlF6 mixtures of different chemical compositions was carried out. The equilibrium composition of the liquid and the solid phase while cooling the slags from 1673K to 298K was computed using FactSage 6.2 software. The performed equilibrium computations indicated that the slags were not entirely liquid at those temperatures. The addition of cryolite causes a substantial increase of the liquid phase of the slag. It also has a favourable effect on the dephosphorization grade of hot metal. The obtained results were statistically processed and presented in the form of regression equations.

  4. Combination of Slag, Limestone and Sedimentary Apatite in Columns for Phosphorus Removal from Sludge Fish Farm Effluents

    Florent Chazarenc


    Full Text Available Laboratory scale studies have repeatedly reported high P-retention in slag, a by-product of the steel manufacturing industry. Thus, it has emerged as a potential material to increase P-removal from constructed wetlands (CWs. However, several limitations were highlighted by field experiments, including the high pH of treated water and clogging. We hypothesized that the addition of sedimentary rocks to slag would preserve P-removal properties while reducing the pH of treated water. Four 2.5 L-columns were filled with 100% apatite (column A; a 50% weight each mixture of limestone with apatite (column B; 10% steel slag located at the inlet, plus 45% limestone mixed with 45% apatite (column C; and a mixture of steel slag (10%, limestone (45% apatite (45% (column D. A synthetic effluent (26 mg P/L and a reconstituted sludge fish farm effluent containing 97 mg/L total suspended solids (TSS, 220 mg/L chemical oxygen demand (COD and 23.5 mg P/L phosphorus (P were applied sequentially during 373 and 176 days, under saturated flow conditions and 12–24 hours hydraulic residence time (HRT, respectively. Treatment performance, P-removal, pH and calcium (Ca2+ were monitored. Results indicated that columns that contained 10% weight steel slag resulted in a higher P retention capacity than the columns without steel slag. The highest P removal was achieved in column C, containing a layer of slag in the inlet zone, 45% apatite and 45% limestone. Feeding the columns with a reconstituted fish farm effluent led to biofilm development, but this had little effect on the P-removal. A combination of slag and sedimentary rocks represents a promising filtration material that could be useful downstream of CWs to further increase P-removal.

  5. The Effects of Different P2O5 Content and Basicity on Phosphorus Enrichment in the CaO-SiO2-FetO-P2O5 Slag System

    Zhao, L. H.; Zhang, Y. J.; Zhou, H. M.; Xu, P.; Bao, Y. P.


    To improve the additional value of phosphorusenrichment phase in slag, it is necessary to make phosphorus to be enriched in the slag. This paper elaborates the effects of different P2O5 content and basicity on phosphorus enrichment in the CaO-SiO2-FetO-P2O5 slag system through the experiment. Slag morphology can be observed by SEM+EDS and the composition of the phase can be ascertained by XRD. Then Lp and Cp in both phosphorus-enrichment phase and matrix phase were calculated respectively. It has been found that P2O5 content in the slag and the basicity of the slag have effects on the existing form of the phosphorus in the slag, and also influence the distribution ratio of P2O5 in the slag.

  6. Phosphorus removal performance and speciation in virgin and modified argon oxygen decarburisation slag designed for wastewater treatment.

    Zuo, Minyu; Renman, Gunno; Gustafsson, Jon Petter; Renman, Agnieszka


    Argon oxygen decarburisation (AOD) slag may be used for phosphorus (P) removal, as its high pH and weatherable calcium (Ca) minerals provide sufficient Ca(2+) and OH(-) for calcium phosphate (Ca-PO4) precipitation. This study examined the P removal performance of AOD slag for use as wastewater treatment material. Batch experiments were carried out using both synthetic P solution and real wastewater, followed by chemical modelling and X-ray absorption near edge structure (XANES) spectroscopy. The influences of initial P concentration, slag dose and modification by polyethylene glycol (PEG), an effective agent for generation of porous materials, were investigated to determine the optimal conditions for P removal by AOD slag. It was found that virgin AOD slag removed 94.8% of P from a synthetic P solution in 4 h and 97.8% in 10 h. This high P removal was accompanied by a rapid increase in pH from 7.0 to 10.74. The maximum P removal capacity (PRC) from synthetic P solution ranged from 1.3 to 27.5 mg P g(-1). The optimal AOD dose for P removal from wastewater, determined in 8-h batch experiments, was 25 g L(-1). PEG modification increased the reaction rate and resulted in higher final pH, increasing PRC by 47.9%. Combined Visual MINTEQ and XANES analysis for detailed examination of P removal mechanisms revealed that the main P removal mechanism was precipitation of calcium phosphate. According to the XANES analysis, the main Ca-PO4 precipitate formed on virgin AOD slag under low initial P concentration and high pH was apatite, while brushite was the dominant product at high initial P concentration and low pH.

  7. Seasonal variations of phytoplankton phosphorus stress in the Yellow Sea Cold Water Mass

    WANG Dan; HUANG Bangqin; LIU Xin; LIU Guimei; WANG Hui


    The Yellow Sea is located between the China Mainland and the Korean Peninsula, representing a typical shallow epicontinental sea. The Yellow Sea Cold Water Mass (YSCWM) is one of the most important physical features in the Yellow Sea. The characteristics of vertical profiles and seasonal variations of biogenic ele-ments in the YSCWM may lead the variations of nutrient availability (e.g., phosphorus) and phosphorus stress of phytoplankton. In this study, the authors surveyed the seasonal variations of phytoplankton phos-phorus stress with emphasis on the effect of the YSCWM during the four cruises in April and October 2006, March and August 2007. Using both bulk and single-cell alkaline phosphatase activity (APA) assays, this study evaluated phosphorus status of phytoplankton community, succession of phytoplankton community and ecophysiological responses of phytoplankton to phosphorus in the typical region of the YSCWM. With the occurrence of the YSCWM, especially the variations of concentration of dissolved inorganic phospho-rus (DIP), the results of bulk APA appeared corresponding seasonal variations. Along Transects A and B, the mean APA in August was the highest, and that in March was the lowest. According to the ELF-labeled assay’s results, seasonal variations of the ELF-labeled percentages within dominant species indicated that diatoms were dominant in March, April and October, while dinoflagellates were dominant in August. During the four cruises, the ELF-labeled percentages of diatoms except Paralia sulcata showed that diatoms were not phosphorus deficient in April 2006 at all, but suffered from severe phosphorus stress in August 2007. In comparison, the ELF-labeled percentages of dinoflagellates were all above 50%during the four time series, which meant dinoflagellates such as Alexandrium and Scrippsiella, sustained perennial phosphorus stress.

  8. Phosphorus Removal Efficiency of Hydrothermally Modified Granular Steel Slag%水热改性颗粒钢渣的除磷效能

    李延波; 邱立平; 王广伟; 张守彬; 翟学东; 马军


    研究了水热改性颗粒钢渣对低浓度含磷废水的除磷效能及影响因素.结果表明,与普通钢渣相比,改性钢渣的除磷能力显著提高,且适宜的废水pH值范围更广;当初始磷浓度为10mg/L、改性钢渣投量为20g/L时,反应2 h后即可使磷浓度降到0.1 mg/L以下.改性前钢渣主要通过离子交换吸附作用除磷,改性后钢渣则主要通过化学沉淀作用除磷.XRD表征结果显示,普通钢渣表面的矿物活性在水热及激发剂的条件下被活化,并生成利于磷酸盐在其表面富集沉淀的水化硅酸钙和氢氧化钙;改性钢渣除磷反应的产物主要为非单一晶形或无晶形的磷酸钙沉淀.%The efficiency and influence factors of phosphorus removal from low-concentration phosphorus-containing wastewater by hydrothermally modified granular steel slag were evaluated.The results show that the modified steel slag is more efficient than raw steel slag in phosphorus removal, and the suitable pH range of wastewater is wider.When the initial phosphorus concentration is 10 mg/L and the modified steel slag dosage is 20 g/L, the phosphorus concentration can be decreased to less than 0.1mg/L after 2 h.The mechanism of phosphorus removal by raw steel slag is mainly through ion exchange adsorption, which is different from that of modified steel slag with chemical precipitation.The results of XRD show that the activity of the minerals on the surface of raw steel slag can be activated by activators under hydrothermal condition, the calcium silicate hydrate and calcium hydroxide are the main hydrated products which can promote the phosphate to precipitate on the steel slag.The reaction products from phosphorus removal by modified steel slag are amorphous calcium phosphate or mixtures of non-single crystal calcium phosphates.

  9. Phosphorus-bearing phases as archaeopetrogenetic indicator for possible bone-rock interactions in pyrometamorphic slags from ritual immolation sites

    Tropper, Peter; Spielmann, Magdalena


    Although 200 ritual immolation sites occur throughout the Eastern Alps only 2 have been investigated from a mineralogical/petrological point of view. The investigated sites (Oetz, Goldbichl/Igls) are located on hill-tops and show abundant ceramic and bone fragments. In these sites pyrometamorphic slags occur (in Oetz only little, at the Goldbichl, massive amounts). The textures within these slags indicate strongly disequilibrium conditions. Investigations of slags from two ritual immolation sites in the Eastern Alps, the La-Tène (450 - 15 B.C.) age site in Oetz and the Bronze-Age site at the Goldbichl/Igls yielded the occurrence of phosphorus-rich olivines and phosphates such as whitlockite (Oetz) and stanfieldite (Goldbichl). Temperatures derived from the slags are >1000-1100°C under highly reducing (QFM) conditions. On the other hand bone apatite crystallinity of calcinated bones yields much lower temperatures this might be due to their position in "cooler" spots of the fire (e.g. at the surface). The high temperatures deduced from the slags are compatible with core temperatures (>1100°C) of large bone fires with a possible wind-driven air circulation. Experimental investigations using DTA-TG to study chlorite breakdown verify these temperatures. In order to verify the presence of P-bearing phases during bone-rock interactions experiments were carried out at 1100-1300°C and highly-reducing conditions in graphite crucibles. Experiments concerning the interaction of bone material and three different rock types such as paragneiss, quartzphyllite and granite led to the formation of whitlockite and P-bearing olivine. Olivine contains 0-4.6 wt.%, P2O5 where the highest P-contents were observed in the quartzphyllite experiments. The occurrence of P-rich olivine and whitlockite in the quartzphyllite experiments is therefore diagnostic for bone-rock interaction at high temperatures. Based on the mineralogical observations from the two sites P-rich minerals which

  10. Phosphorus Sorption Capacities of Steel Slag in Pilot-Scale Constructed Wetlands for Treating Urban Runoff: Saturation Potential and Longevity

    Guo, W. J.; Zhao, L. Y.; Zhao, W. H.; Li, Q. Y.; Wu, Z. B.


    Two parallel pilot-scale integrated constructed wetland (ICW) systems were constructed on the bank of Nanfeihe River. The phosphate (PO4 3-) isothermal adsorption properties of the upper substrate steel furnace slag (SFS) in up-flow chamber was investigated during one-year operation period. The maximum phosphorus (P) adsorption capacity of SFS 9, 11, 13, 15, 17, 19 months service time were 848.9 mg/kg, 968.1 mg/kg, 824.5 mg/kg, 788.7 mg/kg, 864.7 mg/kg and 960.3 mg/kg, respectively. The saturated adsorption amount of SFS had not decreased with the service time prolonging in ICW. The longevity of a full-scale system could not be reliably estimated only based on the theoretical saturated adsorption capacity from laboratory experiments.

  11. Yellow phosphorus process to convert toxic chemicals to non-toxic products

    Chang, S.G.


    The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O[sub 3], PO, PO[sub 2], etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like. 20 figs.

  12. Phosphorus removal mechanisms at the Yellow River Sweetwater Creek Water Reclamation Facility, Gwinnett County, Georgia. Master's thesis

    Borowy, J.T.


    This research investigated the capabilities of the Yellow River Sweetwater Creek Water Reclamation Facility in Gwinnett County, GA. to remove phosphorus biologically. Phosphorus levels and removal locations were analyzed in plant operational units (sampling events), while in reactor experiments (pilot studies), waste was subjected to various conditions to promote-biological phosphorus release and uptake. Analysis of plant conditions at the time of experimentation indicates that one-half of the plant phosphorus removal is accomplished biologically through incorporation of phosphorus in microbial cells during growth. It does not appear, however, that enhanced biological phosphorus removal (BPR) is possible due to wastestream characteristics and/or microbial population. It was noted that the basic anaerobic-aerobic sequence associated with enhanced BPR appears to be occurring with the secondary clarifier sludge blanket and return to compartment A of the nitrification basin.

  13. 磷渣粉对活性粉末混凝土性能的影响%Effects of Phosphorus Slag Powders on Performance of Reactive Powder Concrete



    研究了不同磷渣粉掺量对活性粉末混凝土力学性能及耐久性能的影响。结果表明:磷渣粉的掺入能有效改善RPC混凝土微结构,磷渣粉水化生成的水化产物C-S-H增加混凝土密实度,使得混凝土具有较好的力学性能及耐久性能。但随着磷渣粉掺入量的增加,水泥含量减少,导致体系中Ca( OH)2含量的减少,在弱碱环境下,抑制了磷渣粉的二次水化,活性粉末混凝土性能下降。在蒸汽养护条件下,磷渣粉掺入量为25%时,活性粉末混凝土抗压强度155.9 MPa、抗折强度24.5 MPa、弹性模量52.8 GPa、抗冻性能大于F500、氯离子渗透量22 C,满足科技基[2006]29号标准要求。%Effect of different phosphorus slag powder contents on mechanical properties and durability of reactive powder concrete was studied. The results indicated that the microstructure of reactive powder concretewasimproved effectively with the addition of phosphorous slag powder, and the density of the concretewasincreased bythe hydration product of phosphorous slag powders. The reactive powder concrete had better mechanical properties and durability. But with the increase of phosphorus slag powder admixture, the cement and calcium hydroxidecontent in the system decreased. The secondary hydration of phosphorus slag powder was inhibitedinweak base environment, resulting in the performance degradation of reactive powder concrete. After the steam curing condition, the reactive powder concrete with phosphorus slag powder 25% had better mechanical properties and durability as follows: the compressive strength of reactive powder concrete 155. 9 MPa, flexural strength 24. 5 MPa, elastic modulus 52. 8 GPa, frost resistance more than F500 , chloride ion penetration 22 C. It attained tothe technicalrequirementsof temporary technological terms reactive powder concretematerial on sidewalk baffle or coverfor passenger dedicated line.

  14. Phosphorus removal by laboratory-scale unvegetated vertical-flow constructed wetland systems using anthracite, steel slag and related blends as substrate.

    Wu, Junmei; He, Feng; Xu, Dong; Wang, Rong; Zhang, Xiangling; Xiao, Enrong; Wu, Zhenbin


    This research aimed to investigate the phosphorus (P) removal of a series of laboratory-scale unvegetated vertical-flow constructed wetland systems using anthracite, steel slag and related blends as substrate in treatment of low concentration domestic sewage. The long-term performance of P removal was firstly studied by using single substrate of anthracite or steel slag, and three systems applying various combined substrates were investigated when the average P loading rate varied between 0.9 and 1.5 g TP/m2 x d. The results demonstrated that both anthracite and steel slag systems were highly effective in removing total P (CTP, 77.17 +/- 23.34% and 90.26 +/- 4.48%) and soluble reactive P (SRP, 92.14 +/- 12.56% and 96.20 +/- 2.58%). The system filled with anthracite, vermiculite and steel slag from the top down removed 82.45 +/- 9.52% and 87.83 +/- 8.58% of TP and SRP, respectively. However, other combined substrate systems showed comparative low and fluctuant P removal. The effluent pH was maintained at 7-9, which met environmental requirements of China. Therefore, anthracite provides a long-term high efficiency of P removal and may be a promising substrate from the standpoint of the effluent pH, and the arrangement of combined substrate has a prominent effect on P removal.

  15. An evaluation of childhood deaths in Turkey due to yellow phosphorus in firecrackers.

    Yilmaz, Riza; Yilmaz, Eyyüp; Ozdemir, Veli; Can, Muhammet; Pakis, Isil; Piskin, Ibrahim E; Dokgoz, Halis; Ozer, Erdal; Numanoglu, Kemal V


    Yellow phosphorus (YP) is a powerful protoplasmic poison used in the manufacturing of matches, pest poisons, firecrackers, firework cracker, lights for watches, military ammunition, and agriculture fertilizer. YP is extremely flammable and toxic and easily absorbed from the gastrointestinal tract. In this study, we examined childhood deaths from 1997 to 2012 resulting from the ingestion of firecrackers. The patients ranged from 2 to 15 years of age and were admitted to the hospital with a variety of symptoms. Those that presented with nausea, vomiting, and hypotension rapidly deteriorated and entered a coma. An autopsy was performed in all but one of the 16 cases reviewed. Macroscopically, the livers had a yellowish discoloration with petechial bleeding. Histopathologic examination revealed acute toxic hepatitis. In conclusion, these firecrackers are found in corner shops throughout Turkey, may cause death in children with little warning, and should be banned to prevent further deaths.

  16. Yellow structurally modified fluorescence in the longhorn beetles Celosterna pollinosa sulfurea and Phosphorus virescens (Cerambycidae)

    Van Hooijdonk, Eloise, E-mail: [Centre de recherche en Physique de la Matière et du Rayonnement (PMR) – Laboratoire de Physique du Solide (LPS), University of Namur - FUNDP, 61 rue de Bruxelles, Namur 5000 (Belgium); Institut des NanoSciences de Paris (INSP), Pierre and Marie Curie University – Paris 6 (UPMC), CNRS-UMR 7588, 4 Place Jussieu, Paris 75005 (France); Barthou, Carlos [Institut des NanoSciences de Paris (INSP), Pierre and Marie Curie University – Paris 6 (UPMC), CNRS-UMR 7588, 4 Place Jussieu, Paris 75005 (France); Vigneron, Jean Pol [Centre de recherche en Physique de la Matière et du Rayonnement (PMR) – Laboratoire de Physique du Solide (LPS), University of Namur - FUNDP, 61 rue de Bruxelles, Namur 5000 (Belgium); Berthier, Serge [Institut des NanoSciences de Paris (INSP), Pierre and Marie Curie University – Paris 6 (UPMC), CNRS-UMR 7588, 4 Place Jussieu, Paris 75005 (France)


    Celosterna pollinosa sulfurea and Phosphorus virescens are longhorn beetles which both have a sulphur-yellow pigmentary coloration and, more surprisingly, a yellow-green fluorescence coloration. In this study, we used a refined experimental examination to characterize the angular distribution of light and unveiled a different behavior between these reflection and emission processes. A key feature of these observations is the peculiar architecture of the scales (a three-dimensional photonic structure), which acts differently on each phenomenon. For reflection, this architecture can be viewed as a scattering device, while, for emission, it can be viewed as a waveguide. These effects were investigated by scanning electron microscopy (SEM), Bidirectional Reflectance Distribution Function (BRDF) diagrams and spectrophotometric measurements. Collection and analysis of data at every emergence direction was found to be crucial when studying optical properties in materials with spatial changes in composition at the scale of the light wavelength. -- Highlights: ► We examine structurally modified fluorescence in two longhorn beetles. ► Reflection and emission are complementary processes in the final visual aspect. ► The specific three-dimensional photonic structure of the scales is the keystone. ► Structure impacts the spatial angular distribution of reflected and emitted light.

  17. Thermodynamic Behavior of Manganese and Phosphorus between Liquid Iron and CaO-MgO-SiO2-Al2O3-FetO-MnO-P2O5 Slags


    The thermodynamic behavior of manganese and phosphorus betwe en liquid iron and CaO-MgO-SiO2-Al2O3-FetO-MnO-P2O5 ladle slag system was addressed by investigating the thermodynamic equilibria between li quid iron containing Mn and P and the ladle slag at 1873K. The Mn dist ribution ratio LMn increases with increasing FetO content and decreasi ng the basicity ((%CaO + %MgO)/ +%Al2O3+%P2O5)) in slag, while the P d istribution ratio LP seems to be increased as FetO content and the bas icity increases. The values of LMn and LP decrease by the addition of Al2O3 into slag. The expression of the dependence of LMn and LP on the basicity and content in slag was obtained.

  18. 磷渣在生产油井水泥中的应用研究%Application of Phosphorus Slag in the Production of Oil Well Cement

    邹兴芳; 朱教群; 陆小黑; 周卫兵


    在快硬早强硅酸盐油井水泥生料中掺入1%~3%磷渣作原料,代替部分石灰石、页岩配料,磷渣的掺入能显著降低烧成温度、减少熟料烧成热耗,改善熟料矿物形成条件和熟料矿物结构。由该熟料生产的油井水泥的早期强度能得到大幅提高,其它相关物理性能优异。%In order to fabricate fast hardening and early strength Portland cement,1%~3% phosphorus slag as raw material which was added into raw mineral as mixture to replace part of the limestone,shale ingredients.Addition of phosphorus slag can significantly reduce sintering temperature and the clinker burning heat consumption,and improve the clinker mineral formation conditions and clinker mineral structure.The early strength of cement produced by the clinker can be greatly improved,and other physical properties are also excellent.

  19. Blast furnace slags as sorbents of phosphate from water solutions.

    Kostura, Bruno; Kulveitová, Hana; Lesko, Juraj


    The paper is focused on the sorption of phosphorus from aqueous solutions by crystalline and amorphous blast furnace slags. Slag sorption kinetics were measured, adsorption tests were carried out and the effect of acidification on the sorption properties of slags was studied. The kinetic measurements confirmed that the sorption of phosphorus on crystalline as well as amorphous slags can be described by a model involving pseudo-second-order reactions. For all slag types, phosphorus sorption follows the Langmuir adsorption isotherm. The acid neutralizing capacities of crystalline and amorphous slags were determined. In the case of the crystalline slags, buffering intervals were found to exist during which the slag minerals dissolve in the sequence bredigite-gehlenite-diaspor. There is a high correlation (R2=0.9989) between ANC3.8 and the saturation capacities of crystalline and amorphous slags.

  20. Preliminary study of the lightweight fired aggregate prepared by phosphorus slag%利用磷渣制备烧结轻集料的初步探索性研究


    主要探讨了磷渣为主要原料,粉煤灰、硅砂为辅料,制备烧结轻集料的实验研究。%Experimental study on the preparation of lightweight fired aggregate by phosphorus slag as the main raw material, and fly ash, silica sand as the additives is carried out.

  1. 磷石膏脱硫钙渣制备轻质碳酸钙%Preparation of light calcium carbonate from phosphorus gypsum desulfurization slag

    时婷; 王新刚; 巫建锋; 杨秀山; 杨林; 王辛龙


    To recycle desulfurization slag from phosphorous gypsum,spherical calcium carbonate was prepared from calcium-containing phosphorus gypsum desulfurization slag. The composition of raw materials were analyzed by XRD and SEM. The main substance was calcium oxide and the main impurity was silica. It also contained a small amount of iron,aluminum and magnesium. A new process leaching desulfurization slag by ammonium chloride and subsequent carbonization was firstly proposed. The affecting factors , such as amount of ammonium chloride , ratio of water and desulfurization slag(mass ratio),and temperature on the performance of leaching were investigated. The optimal conditions were: Amount of ammonium chloride 50% of the total weight of the solid, ratio of water and desulfurization slag 9∶1,temperature 40℃. Conversion of calcium was about 67.98% and removal of silica was 97.80% under the optimal conditions. The purity of the obtained calcium carbonate was 97.90%,sedimentation volume was 3.5mL/g and whiteness was 94.2, meeting the norm of first grade product in(HG/T 2226—2010). Main polymorph of calcium carbonate crystals was vaterite.%为了有效利用磷石膏脱硫钙渣资源,以磷石膏脱硫钙渣为原料合成了球形轻质碳酸钙。本文首先利用XRD 和 SEM 等测试手段分析了磷石膏脱硫钙渣的主要组成是氧化钙,主要杂质为二氧化硅以及少量铁铝镁。在此基础上首次提出了氯化铵浸取磷石膏脱硫钙渣,而后碳化合成轻质碳酸钙的新工艺。探讨了浸取过程中氯化铵的添加量,水与钙渣的液固比(质量比),温度工艺参数对钙浸取率和硅脱除率的影响,确定了较优工艺条件为:氯化铵添加量为总固体质量的50%,水与钙渣的液固比为9∶1,温度为40℃。在该工艺条件下,钙的浸取率可达67.98%,硅的脱除率可达97.80%。对上述浸取液经碳化制备出的轻质碳酸钙,其纯度为97.90%,白度为94.2

  2. Phosphorus speciation and distribution in surface sediments of the Yellow Sea and East China Sea and potential impacts on ecosystem

    SONG Guodong; LIU Sumei


    For better understanding the phosphorus (P) cycle and its impacts on one of the most important fishing grounds and pressures on the marine ecosystem in the Yellow Sea (YS) and East China Sea (ECS), it is essential to distinguish the contents of different P speciation in sediments and have the knowledge of its distribution and bioavailability. In this study, the modified SEDEX procedure was employed to quantify the different forms of P in sediments. The contents of phosphorus fractions in surface sediments were 0.20–0.89μmol/g for exchangeable-P (Exch-P), 0.37–2.86μmol/g for Fe-bound P (Fe-P), 0.61–3.07μmol/g for authigenic Ca-P (ACa-P), 6.39–13.73μmol/g for detrital-P (DAP) and 0.54–10.06μmol/g for organic P (OP). The distribution of Exch-P, Fe-P and OP seemed to be similar. The concentrations of Exch-P, Fe-P and OP were slightly higher in the Yellow Sea than that in the East China Sea, and low concentrations could be observed in the middle part of the ECS and southwest off Cheju Island. The distribution of ACa-P was different from those of Exch-P, Fe-P and OP. DAP was the major fraction of sedimentary P in the research region. The sum of Exch-P, Fe-P and OP may be thought to be potentially bioavailable P in the research region. The percentage of bioavailable P in TP ranged from 13%to 61%. Bioavailable P burial flux that appeared regional differences was affected by sedimentation rates, porosity and bioavailable P content, and the distribution of bioavailable P burial flux were almost the same as that of TP burial flux.

  3. Dietary available phosphorus affected growth performance, body composition, and hepatic antioxidant property of juvenile yellow catfish Pelteobagrus fulvidraco.

    Tang, Qin; Wang, Chunfang; Xie, Congxin; Jin, Jiali; Huang, Yanqing


    An 8-week feeding trial was carried out with juvenile yellow catfish to study the effects of dietary available phosphorus (P) on growth performance, body composition, and hepatic antioxidant property. Six pellet diets were formulated to contain graded available P levels at 0.33, 0.56, 0.81, 1.15, 1.31, and 1.57% of dry matter, respectively. Triplicate tanks with each tank containing 60 juveniles (3.09 ± 0.03 g) were fed one of the six experimental diets for 8 weeks. Specific growth rate, feeding rate, and protein efficiency ratio were significantly higher at 0.81% dietary available P. Efficiency of P utilization distinctly decreased with increasing P level. Body lipid content significantly decreased while body ash and feces P content significantly increased with increasing P level. Quadratic regression analysis indicated that vertebrae P content was maximized at 1.21% dietary available P. Fish fed 1.57% dietary available P had highest activity of hepatic superoxide dismutase and catalase and malonaldehyde content. In conclusion, decreasing dietary available P increased P utilization efficiency and body lipid content while decreased vertebrae P content. Juvenile yellow catfish were subjected to oxidative damage under the condition of high dietary P content (1.57%), and the damage could not be eradicated by their own antioxidant defense system.

  4. Preparation of a new sorbent with hydrated lime and blast furnace slag for phosphorus removal from aqueous solution.

    Gong, Guozhuo; Ye, Shufeng; Tian, Yajun; Wang, Qi; Ni, Jiandi; Chen, Yunfa


    The removal of dissolvable inorganic phosphate (H(2)PO(4)(-)) by sorbents prepared from hydrated lime (HL) and blast furnace slag (BFS) was fundamentally studied by an orthogonal experiment design. Based on statistic analysis, it is revealed that the weight ratio of BFS/HL is the most significant variable, and an optimized preparation condition is figured out. With the increase of HL content, the adsorption capacity increases, suggesting that the HL plays the important role in the removal process in the gross. However, in the lower HL content, it is interesting that the adsorption capacity of as-prepared sorbents exceed the sum of the capacities of the same ratio of BFS and HL. The further analysis indicate the excess capacities linearly depend on the specific surface area of sorbents, suggesting that the removal of H(2)PO(4)(-) is closely related with the microstructure of sorbents in the lower HL content, according to the characterization with SEM, XRD and pore analysis. Additionally, an adsorption model and kinetic are discussed in this paper.

  5. Dissolving mechanism of strain P17 on insoluble phosphorus of yellow-brown soil

    Zhong Chuan-qing


    Full Text Available Strain P17 was a bacterial strain identified as Bacillus megaterium isolated from ground accumulating phosphate rock powder. The fermentation broth of strain P17 and the yellow-brown soil from Nanjing Agricultural University garden were collected to conduct this study. The simulation of fixed insoluble phosphorous forms after applying calcium superphosphate into yellow-brown soil was performed in pots, while available P and total P of soil were extremely positive correlative with those of groundwater. Then the dissolving effect of strain P17 on insoluble P of yellow-brown soil was studied. Results showed that Bacillus megaterium strain P17 had notable solubilizing effect on insoluble phosphates formed when too much water-soluble phosphorous fertilizer used. During 100 days after inoculation, strain P17 was dominant. Until the 120th day, compared with water addition, available P of strain P17 inoculation treated soil increased by 3 times with calcium superphosphate addition. Besides available P, pH, activity of acid and alkaline phosphatase and population of P-solubilizing microbes were detected respectively. P-solubilizing mechanism of P-solubilizing bacteria strain P17 seems to be a synergetic effect of pH decrease, organic acids, phosphatase, etc.

  6. Dissolving mechanism of strain P17 on insoluble phosphorus of yellow-brown soil.

    Zhong, Chuan-qing; Cao, Guang-xiang; Huang, Wei-yi; Luan, Xing-she; Yang, Yi-fei


    Strain P17 was a bacterial strain identified as Bacillus megaterium isolated from ground accumulating phosphate rock powder. The fermentation broth of strain P17 and the yellow-brown soil from Nanjing Agricultural University garden were collected to conduct this study. The simulation of fixed insoluble phosphorous forms after applying calcium superphosphate into yellow-brown soil was performed in pots, while available P and total P of soil were extremely positive correlative with those of groundwater. Then the dissolving effect of strain P17 on insoluble P of yellow-brown soil was studied. Results showed that Bacillus megaterium strain P17 had notable solubilizing effect on insoluble phosphates formed when too much water-soluble phosphorous fertilizer used. During 100 days after inoculation, strain P17 was dominant. Until the 120th day, compared with water addition, available P of strain P17 inoculation treated soil increased by 3 times with calcium superphosphate addition. Besides available P, pH, activity of acid and alkaline phosphatase and population of P-solubilizing microbes were detected respectively. P-solubilizing mechanism of P-solubilizing bacteria strain P17 seems to be a synergetic effect of pH decrease, organic acids, phosphatase, etc.

  7. Distribution, partitioning and sources of dissolved and particulate nitrogen and phosphorus in the north Yellow Sea

    Duan, Li-Qin; Song, Jin-Ming; Yuan, Hua-Mao; Li, Xue-Gang; Li, Ning


    Little is known about characteristics of dissolved and particulate N and P forms in the north Yellow Sea (NYS). In this study, water and particulate samples were collected from the NYS to understand the biogeochemical behaviors, interactions and sources of dissolved and particulate N and P. Among the various N and P forms, dissolved organic N (DON) and P (DOP) were the predominant forms, accounting for 64% and 65% of total N (TN) and P (TP). Dissolved and particulate inorganic N and P displayed a decreasing trend from northwest region to the middle region, which was mainly influenced by riverine input along the Liaodong Peninsula coast. However, dissolved and particulate organic N and P showed higher values at northwest region and southern region, which were dominantly affected by biological activities and the Bohai Sea input. Vertical distribution patterns of dissolved and particulate N and P generally displayed the higher values at surface and bottom waters, which was the combined result of the influences by thermocline, the Yellow Sea Cold Water Mass (YC), biological activities and sediment resuspension. There were significant correlations between dissolved and particulate pools and between inorganic and organic forms, indicating their transformations through phytoplankton and bacteria activities and adsorption/desorption processes. Budgets suggested that net sink of dissolved inorganic N and P in the NYS could be mainly removed from water column. Particulate N and P were mainly from phytoplankton productivity, contributing to 84% and 74% of total particulate N (TPN) and P (TPP) influx.

  8. Determination of hydrogen cyanide in yellow phosphorus tail gas%黄磷尾气中氰化氢的测定

    蒋明; 宁平; 王重华; 田森林; 陈炜; 周键; 王磊


    采用硝酸银容量法规定黄磷尾气中HCN的含量.依照HJ 484-2009氰化物的AgNO3容量法为蓝本,进行方法的改进研究.结果表明,采用改进后的硝酸银容量法较其他方法更优,能彻底消除黄磷尾气中大量H2S的干扰.该方法简单实用重现性好,适用于工作场所空气中和黄磷尾气中HCN的测定.%Silver nitrate ( AgNO3 ) volumetry is used to determine the content of hydrogen cyanide in yellow phosphorus tail gas. The improvement of this determination method is based on HJ 484—2009. The results show that,the improved AgNO3 volumetry has obvious advantages over other methods,which can completely eliminate the interference of H2S in the yellow phosphorus tail gas. It is simple,practical and feasible for the determination of HCN in workshop and yellow phosphorus tail gas with excellent repeatability.

  9. Stagewise processing of yellow water using clinoptilolite for nitrogen and phosphorus recovery and higher residual quality.

    Allar, A D; Beler Baykal, B


    Source-separated human urine may be used as a source of fertilizers indirectly through processing with clinoptilolite. The suggested form of fertilizer is clinoptilolite loaded with plant nutrients from urine, where nitrogen and phosphorus will be released upon contact with water. Triggered by the need for handling high concentrations remaining in the liquid phase to be disposed of, this paper aims to present the option of improving the residual nutrient quality through stagewise processing with clinoptilolite, while investigating any improvement in nutrient removal. Two sets of experiments, stagewise operation under (i) constant loadings and (ii) variable loadings in each stage, are discussed. Stagewise operation has been observed to be successful for attaining reduced residual liquid phase concentrations as well as improvements in nitrogen recovery as compared to single-stage operation. Comparing constant and variable stagewise loadings, the final concentration is 10 times lower with variable loadings. The latter is comparable to a level found in only 1% of conventional domestic wastewater volume. Stagewise operation was beneficial from the standpoint of both additional nutrient recovery and for residuals control, with more pronounced benefits for attaining higher quality residual liquid phase concentrations to be disposed of.

  10. Study on application of composite activator in phosphorus slag powder dry-mix mortar%复合激发剂在磷渣粉干混砂浆中的应用研究

    刘秀伟; 杨林; 秦贤顺


    针对磷渣粉高掺量用于水泥干混砂浆时强度低,凝结时间长等缺点,通过采用多种激发剂硫酸钠、消石灰粉、电石渣、磷石膏、脱硫石膏等来激发其活性,并对激发剂的种类和掺量的作用效果进行了研究,确定出最佳配比,达到在干混砂浆中降低水泥用量,提高磷渣资源化利用率的目的。%According to some shortages of the addition of high mixture of phosphorous slag used in cement dry-mixed mortar with low strength and long setting time,the paper stimulates the activity by adopting activators,sodium sulfate,ground hydrated lime,carbide slag,ardealite,and flue gas desulfurization gypsum,researches the types of the activators and mixing volumes,and identifies the optimal proportional ratio,so as to lower the cement volume and enhance the usage ratio of the phosphorus slag resources.

  11. Particle-size distribution and phosphorus forms as a function of hydrological forcing in the Yellow River.

    Yao, Qing-Zhen; Du, Jun-Tao; Chen, Hong-Tao; Yu, Zhi-Gang


    Samples were collected monthly from January to December in 2010, and daily observations were made during the water-sediment regulation event in June-July 2010. Sequential extractions were applied to determine the forms of P in different particle-size fractions and to assess the potential bioavailability of particulate phosphorus (PP). The results indicated that exchangeable phosphorus, organic phosphorus, authigenic phosphorus, and refractory phosphorus increased with the decreasing of particulate size; conversely, detrital phosphorus decreased with the decreasing of particulate size. The content of bioavailable particulate phosphorus (BAPP) varied greatly in different sizes of particles. In general, the smaller the particle size, the higher the content of bioavailable phosphorus and its proportion in total phosphorous was found in these particles. Hydrological forcing controlled the variability in the major P phases found in the suspended sediments via changes in the sources and the particle grain-size distribution. The variation of particle sizes can be attributed also to different total suspended sediment (TSS) sources. Water-sediment regulation (WSR) mobilized only particulate matter from the riverbed, while during the rainstorm soil erosion and runoff were the main source. The BAPP fluxes associated with the "truly suspended" fraction was approximately 200 times larger than the dissolved inorganic phosphorus (DIP) flux. Thus, the transfer of fine particles to the open sea is most probably accompanied by BAPP release to the DIP and can support greater primary and secondary production.

  12. A Thermodynamic Model for Predicting Phosphorus Partition between CaO-based Slags and Hot Metal during Hot Metal Dephosphorization Pretreatment Process Based on the Ion and Molecule Coexistence Theory

    Yang, Xue-min; Li, Jin-yan; Chai, Guo-ming; Duan, Dong-ping; Zhang, Jian


    A thermodynamic model for predicting phosphorus partition L P between a CaO-based slags and hot metal during hot metal dephosphorization pretreatment process has been developed based on the ion and molecule coexistence theory (IMCT), i.e., the IMCT- L P model. The reaction abilities of structural units or ion couples in the CaO-based slags have been represented by the calculated mass action concentrations N i through the developed IMCT- N i model based on the IMCT. The developed IMCT- L P model has been verified to be valid through comparing with the measured L P as well as the predicted L P by two reported L P models from the literature. Besides the total phosphorus partition L P between the CaO-based slag and hot metal, the respective phosphorus partitions L P, i of nine dephosphorization products as P2O5, 3FeO·P2O5, 4FeO·P2O5, 2CaO·P2O5, 3CaO·P2O5, 4CaO·P2O5, 2MgO·P2O5, 3MgO·P2O5, and 3MnO·P2O5 can also be accurately predicted by the developed IMCT- L P model. The formed 3CaO·P2O5 accounts for 99.20 pct of dephosphorization products comparing with the generated 4CaO·P2O5 for 0.08 pct. The comprehensive effect of CaO+Fe t O, which can be described by the mass percentage ratio (pct Fe t O)/(pct CaO) or the mass action concentration ratio N_{Fe}t O/N_{Fe}t O N_{CaO}. N_{CaO}} as well as the mass percentage product (pct Fe t O) × (pct CaO) or the mass action concentration product N_{{{{Fe}}t {{O}}}}5 × N_{{CaO}}3 , controls dephosphorization ability of the CaO-based slags. A linear relationship of L P against (pct Fe t O)/(pct CaO) can be correlated compared with a parabolic relationship of L P against N_{Fe}t O/N_{Fe}t O N_{CaO}. N_{CaO}, while the linear relationship of L P against (pct Fe t O) × (pct CaO) or N_{Fe}t O5 × N_{CaO}3 can be established. Thus, the mass percentage product (pct Fe t O) × (pct CaO) and the mass action concentration product N_{Fe}t O5 × N_{CaO}3 are recommended to represent the comprehensive effect of CaO+Fe t O on

  13. Interception effect of ditch slag and sediments on nitrogen and phosphorus in water%排水沟渠炉渣与底泥对水中氮、磷截留效应

    张燕; 祝惠; 阎百兴; 邓志强


    In order to discuss the adsorption capacity of nitrogen and phosphorus for slag,70% slag with 30% ditch sediment and ditch sediments,the isothermal adsorption and kinetics experiments were conducted at the comprehensive experimental field of the Sanjiang Mire Wetland Experimental Station(47°35′N,133°3 1′E),Chinese Academy of Sciences.Meanwhile,the experimental data were fitted by the Langmuir isothermal adsorption equation.The maximum ammonium nitrogen adsorption amounts for slag,70% slag with 30% ditch sediment,and ditch sediments were 0.49,1.03and 1.75mg/g,respectively; the maximum phosphate adsorption amounts were 0.99,2.33and 1.88mg/g,respectively; the adsorption rates of ammonium nitrogen were 0.10,0.11and 0.54mg/(g·h) during 0~4h; the adsorption rates of phosphate were 0.048,0.051,0.096mg/(g·h) during 0~2h.Slag was used as matrix dam fill since ditch sediments were loose and easy to run off.The hydraulic retention time of ditch water in drainage ditches was extended with matrix dams as well as mitigating the flow velocity of ditch water.%通过等温热力学吸附实验,将炉渣、炉渣+30%底泥、排水沟渠底泥对水中氨氮的去除效果进行比较,并采用Langmuir等温吸附方程对3种基质吸附氨氮、磷酸盐的量进行拟合;通过动力学实验,比较3种基质吸附速率.结果表明,炉渣、炉渣+30%底泥、排水沟渠底泥对氨氮的最大吸附量分别为0.49,1.03,1.75mg/g,对磷酸盐的最大吸附量分别为0.99,2.33,1.88mg/g;4h内基质吸附氨氮速率分别为:0.10,0.11,0.54mg/(g.h),2h内基质吸附磷酸盐速率分别为:0.048,0.051,0.096mg/(g.h).由于沟渠底泥较为松散、遇水冲刷易流失,故选择炉渣作为沟渠基质坝的填充物.基质坝能够减缓渠水流速,延长渠水的水力停留时间(HRT).

  14. Slag wool manufacturing from blast furnace slag

    Володимир Петрович Руських


    Full Text Available Slag wool is the most expensive and valuable product of blast furnace slag processing. Slag wool is in great demand nowadays. The article highlights the factors influencing the mineral wool quality: chemical composition that determines the acidity of the module, the temperature of the molten slag and the required slag jet thickness consistency. Mineral wool is produced by blowing air or steam into a jet of molten slag. As a result of it the slag crushes into droplets stretching. The resulting wool contains 5% slag and 95% air. The quality of the obtained slag wool depends on the module acidity of the slag. The blast furnace slags of «Ilyich iron and steel works of Mariupol» and «Azovstal iron & steel works» are the main (short slags – they give short fibers. To obtain high-quality long fiber wool it is necessary to add admixtures into basic blast furnace slag to reduce its basicity. As a result of the fuel and energy rising prices and the necessity to reduce the slag wool cost it is necessary to develop a new technology with fiery-liquid slag, with the removal of iron compounds and sulphur from the melts and the introduction of corrective additives to improve the quality of slag wool. Good thermal conductivity (about 0,03 kcal/m∙h∙°C and other indicators (resistance, volume weight make it possible to use the materials from slag wool (pads, rigid and semi-rigid plates as heat and sound insulating materials

  15. Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition.

    Zhang, Ying; Zhang, Chaojie; Zhang, Xuan; Feng, Leiyu; Li, Yongmei; Zhou, Qi


    Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA (volatile fatty acid) in a shorter time can be achieved at pH10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supernatant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.

  16. Dephosphorization Kinetics between Bloated Metal Droplets and Slag Containing FeO: The Influence of CO Bubbles on the Mass Transfer of Phosphorus in the Metal

    Gu, Kezhuan; Dogan, Neslihan; Coley, Kenneth S.


    Dephosphorization kinetics of bloated metal droplets was investigated in the temperature range from 1813 K to 1913 K (1540 °C to 1640 °C). The experimental results showed that the overall mass transfer coefficient, {ko} , decreased with increasing temperature because of decreasing phosphorus partition ratio, {LP} . It was also found that the mass transfer coefficient for phosphorus in the metal, {km} , had the highest value at the lowest temperature [i.e., 1813 K (1540 °C)] because the formation of smaller CO bubbles increased the rate of surface renewal, leading to faster mass transport. Meanwhile, metal droplets without carbon were also employed to study the effect of decarburization on dephosphorization. The results show that although decarburization lowers the driving force significantly, {km} (6.2 × 10-2 cm/s) for a carbon containing droplet is two orders of magnitude higher than that for carbon free droplets (5.3 × 10-4 cm/s) because of the stirring effect provided by CO bubbles. This stirring offers a faster surface renewal rate, which surpasses the loss of driving force and then leads to a faster dephosphorization rate.

  17. Distribution of carbon, nitrogen and phosphorus in coastal wetland soil related land use in the Modern Yellow River Delta

    Yu, Junbao; Zhan, Chao; Li, Yunzhao; Zhou, Di; Fu, Yuqin; Chu, Xiaojing; Xing, Qinghui; Han, Guangxuan; Wang, Guangmei; Guan, Bo; Wang, Qing


    The delivery and distribution of nutrients in coastal wetland ecosystems is much related to the land use. The spatial variations of TOC, TN, NH4+-N, NO3--N and TP and associated soil salinity with depth in 9 kinds land uses in coastal zone of the modern Yellow River Delta (YRD) was evaluated based on monitoring data in field from 2009 to 2015. The results showed that the average contents of soil TOC, TN, NO3--N, NH4+-N and TP were 4.21 ± 2.40 g kg-1, 375.91 ± 213.44, 5.36 ± 9.59 and 7.20 ± 5.58 and 591.27 ± 91.16 mg kg-1, respectively. The high N and C contents were found in cropland in southern part and low values in natural wetland, while TP was relatively stable both in profiles and in different land uses. The land use, land formation age and salinity were important factors influencing distributions of TOC and N. Higher contents of TOC and N were observed in older formation age lands in whole study region, while the opposite regulation were found in new-born natural wetland, indicating that the anthropogenic activities could greatly alter the original distribution regulations of nutrients in coastal natural wetlands by changing the regional land use.

  18. 钒钼黄比色法测定食品中磷的研究%Study on the Determination of Phosphorus in Food Based on Vanadium Molybdenum Yellow Colorimetric Method

    向晓黎; 王静; 王国红


    The article aims to set up the techniques to detect phosphorus in food based on the vanadium molybdenum yellow colorimetric method.Through the adjustment of the acidity of digestion solution and the replacement of the color agent , the content of phosphorus in food can be determined by vanadium molybdenum yellow spectrophotometry.When the Phosphorus solution concentration is in the range of 1mg/L to 20 mg/L ,the linear regression is fine;the recovery rate is in the range of 94 % to 97 %.The determination of the national standard reference materials by this method and comparison with the national standard method's determination of phosphorus in food ,the results show no obvious distinctions betw een the tw o methods'results in statistics ,w hich proves that this method can be applied to the determination of phosphorus in food.%建立了钒钼黄比色法测定食品中磷的检测技术 ,该法通过消解液酸度的调节 ,显色剂的替换 ,应用钒钼黄比色法测定食品中磷的含量.当磷溶液浓度范围在[1mg/L~20 mg/L ]时 ,线性回归良好 ;回收率范围为94%~97% .用此法测定了国家标准参考物质 ,与国标方法测定食品中磷的含量进行了比对 ,结果表明 :测定结果与国标方法的测定结果比较无显著统计学差别 ,说明该方法可用于食品中磷的测定.

  19. Phosphorus speciation in the sediments of the Bohai Sea and North Yellow Sea%北黄海与渤海沉积物中磷形态的分布特征

    董方; 刘素美; 张经


    对1998年9月和1999年5月渤海航次和1999年8月北黄海航次所采集的柱状沉积物和表层沉积物样品进行了P形态的六步连续提取分析,分析了各种形态P在表层及垂直方向上的分布特征。并通过对沉积物充空气和N2条件下培养前后各步形态P的测定,认识各步形态 P培养前后的变化以及不同的氧化还原环境对各步形态P的影响。结果表明:从渤海到北黄海总P的含量逐步降低。碎屑磷灰石的含量在六步中含量最高,约占50%左右,其次是非活性有机磷,约占20%,其他几步含量较小;充N2培养沉积物样品中碎屑磷灰石的含量要比充空气的低,其他形态的P较充空气培养的略高或相差不大。%Surface and core sediment samples were collected in September 19 98 and May 1999 in the Bohai Sea, August 1999 in the North Yellow Sea. A six ste ps sequential extraction technique was used for the sediment samples. The conten ts of total phosphorus decreased gradually from the Bohai Sea to the Yellow Sea. The contents of edtrital apatite were the highest in the six phosphorus forms a ccounting for ca. 50%, followed by refractory organic phosphorus accounting for ca. 20%, then authigenic apatite, CaCO3-bound inorganic phosphorus and leacha ble organic phosphorus, adsorbed inorganic phosphorus, iron-bound inorganic ph osphorus, CaCO3-adsorbde inorganic phosphorus, loosely adsorbed inorganic pho sphorus. In the incubated core sediment samples bubbled with air or nitrogen, th e contents of phosphorus fractions in sediment incubated with nitrogen were high er than or similar to that with air except detrital apatite.

  20. Efeito da escória de siderurgia e calcário na disponibilidade de fósforo de um Latossolo Vermelho-Amarelo cultivado com cana-de-açúcar Effect of slag and limestone on the availability of phosphorus of an Oxisol planted with sugarcane

    Renato de Mello Prado


    Full Text Available O objetivo deste trabalho foi avaliar o efeito da escória de siderurgia e calcário na concentração do P disponível em um Latossolo Vermelho-Amarelo, cultivado com cana-de-açúcar (Saccharum spp., em Ituverava, SP. Foram aplicados calcário calcítico e a escória de siderurgia, objetivando elevar a saturação por bases a 50%, 75% e 100%, e usou-se testemunha (sem correção. O efeito linear da escória de siderurgia no P disponível do solo, em contraste com a ausência de relação quando se aplicou calcário, sugere que o efeito positivo da escória de siderurgia se deve mais ao efeito do silicato, de saturar os sítios de adsorção de P, do que ao efeito de aumento do pH.The aim of this work was to evaluate the effect of slag and limestone, on the available P concentration of the soil planted with sugarcane. A field experiment was conducted in Ituverava, SP, Brazil, in a Red-Yellow Oxisol. Calcitic limestone and the slag were added in order to increase the base saturation to 50%, 75% and 100%, in addition to the control without correction. The linear effect of the slag on the soil available P, contrasting the lack of relationship when the limestone was applied, suggests that the positive effect of the slag is mainly due to the silicate effect than to the pH effect.


    Rogério Antônio de Freitas Lima


    Full Text Available

    The study was carried out to evaluate the effects of simultaneous application of triple superphosphate and zinc sulphate on growth of passion fruit (Passiflora edulis f. flavicarpa seedlings. A nursery experiment for seedling formation was conducted at the Department of Agricultural Production of the Mato Grosso do Sul State University, Cassilândia Unit (UEMS/UUC, Brazil. Four doses of phosphorus (0 mg dm-3, 150 mg dm-3, 300 mg dm-3 and 450 mg dm-3 and three doses of zinc (0 mg dm-3, 5 mg dm-3 and 10 mg dm-3 were tested. The phosphorus was used as triple superphosphate, and the zinc as zinc sulphate. A randomized block design was used, in a 4 x 3 factorial scheme with four replications and five plants per plot. The following traits were evaluated 92 days after sowing: height, root length, number of leaves per plant, dry matter of shoots and roots, and total dry matter. The application of triple superphosphate affected significantly height of plants, leaf number, shoots dry matter, and total dry matter. The zinc sulphate favored the variables height, shoot dry matter, and total dry matter. It was concluded that the use of triple superphosphate and zinc sulphate provided a better quality in the production of the yellow passion fruit seedlings.

    KEY WORDS: Passiflora edulis f. Flavicarpa; passion fruit; propagation; seedling.

    O trabalho foi desenvolvido para avaliar os efeitos da aplicação simultânea de superfosfato triplo e sulfato de zinco na formação de mudas de maracujazeiro-amarelo (Passiflora edulis f. flavicarpa. Para isso, foi conduzido um experimento em viveiro de formação de mudas, no setor de produção agrícola da Universidade Estadual do Mato Grosso do Sul (UEMS, Unidade Universitária de Cassilândia (UUC. Foram testadas quatro

  2. 黄水为碳源的颗粒污泥除磷机理研究%Phosphorus Removal Mechanism of Granular Sludge with Yellow Water as Carbon Source Study

    刘思琪; 胡学斌; 刘小英


    Granular sludge ,as a biological treatment technology concerned in recent years ,has compact structure ,good settling ability and perfect biological activity .In order to understand the mechanism of phosphorus removal of aerobic granu-lar sludge which is fed by the yellow water ,the physical characteristics and the phosphorus removal characteristic of granular sludge are seriously studied ,especially the shape and content of phosphorus in granular sludge .Meanwhile the different ex-traction methods and the effects on the phosphorus removal of extracellular polymeric substances (EPS ) are also studied .The phosphorus removal mechanisms of granular sludge are described ,which provides theoretical and technical support for the realization of high efficiency and low consumption phosphorus removal in urban sewage using granular sludge for simultaneous removal of nitrogen and phosphorus .%颗粒污泥作为近年来备受关注的一种生物处理技术,具有结构密实、沉降性好、生物相丰富且活性高等优点。为了了解好氧颗粒污泥除磷机理,以黄水为碳源的同步脱氮除磷颗粒污泥为研究对象,研究颗粒污泥的物理特性、除磷特性,重点研究颗粒污泥中磷的形态及含量,同时研究不同方法对颗粒污泥胞外聚合物(EPS )的提取效果及其对磷去除的影响,揭示该颗粒污泥的除磷机理,为城市污水利用同步脱氮除磷颗粒污泥实现高效低耗除磷提供理论与技术支持。

  3. Effect of P2O5 and FetO on the Viscosity and Slag Structure in Steelmaking Slags

    Wang, Z. J.; Shu, Q. F.; Sridhar, S.; Zhang, M.; Guo, M.; Zhang, Z. T.


    The present paper investigates the influence of P2O5 and FetO on the viscosity and structure of steelmaking slags. An understanding of the viscous behavior and structure of FetO-bearing smelting slags is essential to control the dephosphorization in steelmaking process and to efficiently recycle the phosphorus from steelmaking slags. It is found that the viscosity of CaO-SiO2-Al2O3-MgO-FetO-P2O5 slags slightly increases with increasing P2O5 content, while the viscosity decreases with increasing FetO content. The degree of the polymerization of quenched slags, determined from Raman spectra, is found to increase with increasing P2O5 content and decrease with increasing FetO content. It is also noted that the peaks of Raman spectra between 800 and 1200 cm-1 were nearly absent at the FetO content of 22.46 wt pct; whereas according to 29Si MAS-NMR and FTIR analysis, it is clearly seen that the [SiO4]-tetrahedra-related peaks existed even for the same slag. This may confirm that small quantities of extra-framework iron species can absorb the Raman scattering and damp the Raman signal intensity and the presence of FetO in the slag does not necessarily eliminate [SiO4]-tetrahedra.

  4. 磷渣微粉基隧道沥青路面阻燃剂的制备及其性能试验%Preparation and performance test phosphorus slag powder base tunnel asphalt pavement retardants

    钱国平; 王坤; 郑卫芳


    针对隧道沥青路面防火安全问题,配制了6种磷渣微粉基材阻燃剂 A~F。通过 DSC 试验评价了各阻燃剂阻燃性能,选出了最优阻燃剂;对掺入不同掺量的阻燃改性沥青进行路用性能试验和极限氧指数试验,分析了阻燃剂最佳掺量和阻燃效果;采用锥形热试验对阻燃沥青混合料进行阻燃性能研究。试验结果表明,阻燃剂 D,F 有明显的两个吸热峰;阻燃剂 D 和 F 的加入使沥青的氧指数得到显著的提高;不同掺量阻燃剂 D,F 的加入,能够满足沥青路用性能的要求,阻燃剂的最佳掺量为8%;与非阻燃改性沥青混合料相比,阻燃改性沥青的引燃时间变长,热释放速率减缓,总释热量全过程低于非阻燃沥青混合料。阻燃剂 D,F 的加入对沥青及沥青混合料的阻燃效果明显,且阻燃剂 D 阻燃效果最优。%Six kinds of phosphorus slag powder-based flame retardants were prepared in or-der to solve fire-proof safety problem of tunnel asphalt pavement A-F.The combustion prop-erties of flame retardants were evaluated by DSC experiment and the optimal flame retard-ants were selected.The pavement performance and limiting oxygen index of flame-retardant modified asphalt with different amounts of retardants were tested,then the optimum a-mount of flame retardants and flame retardancy were analyzed.The Cone thermal test was conducted to study the flame retardant properties of flame retardant asphalt mixture.the re-sults show that flame D,F two endothermic peaks are obvious.With the addition of flame retardant D and F,the oxygen index of asphalt was significantly improved.Different dosage of the addition of flame retardant D,F can meet the requirements of the pavement perform-ance.The optimum amount of flame retardant is 8%.Compared with the nonflame-retardant asphalt mixture,the retardancy of flame-retardant modified asphalt mixture is better:its ig-nition time is longer,heat release rate is slower and the

  5. performance of steel slag performance of steel slag as fine ...


    reduced from 0.62 to 0.50 as slag proportion increased from 0% to 100% at slump. 0.62 to 0.50 as slag ... Nigerian Journal of Technology (NIJOTECH). Vol. 34 No. 3, July ... scrap metals and hundreds of tonnes of steel slag are produced every ...

  6. Thermodynamic Study on BaO-CaO-CaF2 Slags for Dephosphorization of Molten Steel

    TIAN Zhi-hong; CAI Kai-ke; WANG Xin-hua; ZHU Li-xin; WANG Tao; SHI Hong-zhi; YIN Xiao-dong


    The molten steel was dephosphorized by high basic BaO-based slags (BaO-CaO-CaF2) to achieve ultra low phosphorus level. The dephosphorization ability of the BaO-CaO-CaF2 slags was tested. The phosphate capacity of this slag system at 1 620 C varied from 1018.03 to 1019.11 with an activity coefficient of P2O5 ranging from 10-19.47 to 10-18.09. The effect of BaO content, initial phosphorus content and oxygen potential of molten steel on dephosphorization was discussed. The phosphorus pick-up by the BaO-based slags was studied.

  7. Converter slag-coal cinder columns for the removal of phosphorous and other pollutants.

    Yang, Jian; Wang, Su; Lu, Zhibo; Yang, Jian; Lou, Shanjie


    A mixture of converter slag and coal cinder as adsorbent for the removal of phosphorous and other pollutants was studied in the paper. The maximum P adsorption capacity, pH of solution, contact time and initial phosphate concentration were evaluated in batch experiments for the two materials firstly. The data of P sorption were best fitted to Langumir equation, and the maximum adsorption capacities of converter slag and coal cinder were 2.417 and 0.398 mg P/g, respectively. The pH of solutions with converter slag and coal cinder changed dramatically with time and closed to 8 in 8h, and the influence of initial pH on phosphate removal by coal cinder was more significant than by converter slag. Phosphate removal rate by converter slag decreased with increase of initial phosphate concentrations. Subsequently, two flow-through columns (Column 1#, V(converter slag):V(coal cinder)=1:5; Column 2#, V(converter slag):V(coal cinder)=1:3) were operated for the removal of phosphorous and other pollutants from the effluents of a vermifilter for nearly eleven months. Results indicated the average removal efficiency of total phosphorus, dissolved phosphorus, COD and NH(4)(+)-N by Column 1# were 44%, 56%, 31% and 67%, and by Column 2# were 42%, 54%, 24% and 57%, respectively. Column 1# had higher removal efficiency for P and other pollutants.

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

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


    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.

  9. Effects of Straw-Based Soil Conditioners on Available Phosphorus Contents in Sandy Yellow Soil%秸秆改良材料对冷沙黄泥中速效磷含量的影响

    赵蕾; 杨巍; 王定勇


    Crop straws (rice straw, wheat straw, maize straw and rape straw) were mixed with bentonite and polyacrylamide (PAM) to make straw-based soil conditioners, which were used in a pot experiment tc investigate their effects on available phosphorus (P) content in a sandy yellow soil widely distributed in Chongqing. The results indicated that all the 4 materials significantly increased the content of available P in the soil, the order of increment being rape straw (39. 4%~55. 7%) > maize straw (38. 9%~54. 8 2%) > wheat straw (34. 5%~46. 1%) > rice straw (28. 1% ~42. 5%). With the same straw, Treatment 3 (straw : bentonite : PAM = 900 : 100 : 30) showed the greatest soil amelioration effect by increasing available phosphorus (P) in the sandy yellow soil.%以重庆分布面积较大的沙质土壤--冷沙黄泥为研究对象,将秸秆进行生物顸处理后与膨润土、聚丙烯酰胺(PAM)按比例配制成土壤改良材料,采用盆栽土培试验方法,研究了水稻、小麦、玉米和油菜4种秸秆改良材料对冷沙黄泥速效磷含量的影响.结果表明:(1)4种秸秆改良材料均能明显提高冷沙黄泥的速效磷含量,其顺序由高到低为油菜、玉米、水稻和小麦,它们施入土壤后速效磷的平均含量分别增长了约39.4%~55.7%,38.9%~54.8%,34.5%~46.1%和28.1%~42.5%.(2)相同秸秆条件下不同分处理对土壤速效磷的增磷效果有所差异,其中秸秆:膨润土:PAM=900:100:30的T3处理对提高土壤有效磷含量的效果最好.

  10. A Blended Cement Containing Blast Furnace Slag and Phosphorous Slag


    Blended cement containing blast furnace slag(BFS) and phosphorous slag(PS) is a new kind of cement.The total content of blended materials could increase if two additives were used. Using the same admixtures, the properties of the blended cement with 70% additives could reach the standard of 525-grade slag cement according to GB.The strength of cement with 80% additives could reach the standard of 425-grade slag cement.The tests of strength, pore structure,hydration products,inhibiting alkali-aggregate reaction, resistance to sulfate corrosion of BFS-PSC were performed.

  11. Hydraulic properties of ladle slags

    J. Vlček


    Full Text Available The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability.

  12. Refractories Utilizability for Slagging Gasifiers


    Slagging coal gasification process became a highlight of coal chemical industry in China during the last decade. Refractory lining's life of slagging gasifiers is one of the most critical factors for a cost -effective operation. The paper introduces current status of coal gasification in China, lining structure of slagging gasifiers and performance of refractory lining. It also summarizes the major factors impacting on refractory wear in slagging coal gasifiers in four Chinese chemical plants, based on ten years of industrial experience. The utilizability is discussed in terms of cost -effectiveness of high chromia refractories and possibility of the alternatives.

  13. Yellow fever.

    Monath, Thomas P; Vasconcelos, Pedro F C


    Yellow fever, a mosquito-borne flavivirus disease occurs in tropical areas of South America and Africa. It is a disease of major historical importance, but remains a threat to travelers to and residents of endemic areas despite the availability of an effective vaccine for nearly 70 years. An important aspect is the receptivity of many non-endemic areas to introduction and spread of yellow fever. This paper reviews the clinical aspects, pathogenesis, and epidemiology of yellow fever, with an emphasis on recent changes in the distribution and incidence of the disease. Recent knowledge about yellow fever 17D vaccine mechanism of action and safety are discussed.

  14. Distribution behavior of phosphorus in the coal-based reduction of high-phosphorus-content oolitic iron ore

    Yong-sheng Sun; Yue-xin Han; Peng Gao; Duo-zhen Ren


    This study focuses on the reduction of phosphorus from high-phosphorus-content oolitic iron ore via coal-based reduction. The distribution behavior of phosphorus (i.e., the phosphorus content and the phosphorus distribution ratio in the metal, slag, and gas phases) during reduction was investigated in detail. Experimental results showed that the distribution behavior of phosphorus was strongly influenced by the reduction temperature, the reduction time, and the C/O molar ratio. A higher temperature and a longer reaction time were more favor-able for phosphorus reduction and enrichment in the metal phase. An increase in the C/O ratio improved phosphorus reduction but also hin-dered the mass transfer of the reduced phosphorus when the C/O ratio exceeded 2.0. According to scanning electron microscopy analysis, the iron ore was transformed from an integral structure to metal and slag fractions during the reduction process. Apatite in the ore was reduced to P, and the reduced P was mainly enriched in the metal phase. These results suggest that the proposed method may enable utilization of high-phosphorus-content oolitic iron ore resources.

  15. A Laboratory Study of the Treatability of Synthetic Stormwater Under Varying Conditions Using Electric Arc Furnace Steel Slag

    Nnaemeka C. Okochi


    Full Text Available The investigation of electric arc furnace (EAF steel slag as a viable add-on technology to existing stormwater systems for the removal of dissolved phosphorus (P was extended to explore the effects of varying environmental and treatment system conditions. Parameters such as stormwater composition, P concentration, metal concentration, pH, temperature, slag mass and slag particle size were varied. Observations relating to the method of P removal via EAF slag were also carefully considered to explain removal mechanisms involved. Results demonstrated that, although physisorption contributed to P reduction, it was not the key P removal mechanism. Instead, precipitation was observed to be a key removal pathway as evidenced by the correlation between the loss of iron (Fe from slag and the amount of P removed from solution. The reduced removal of P by slag in a copper-dominant stormwater solution was attributed to the formation of a stable complex formed by the interaction of copper with the slag via the ion-exchange surface model. The stability of this complex inhibits the loss of Fe from the EAF slag and, consequently, P removal by means of precipitation. In terms of the effect of changing environmental and treatment system conditions on the P removal process, stormwater composition, P concentration, metal concentration, pH, temperature, slag mass and slag particle size were found to significantly influence the effectiveness of EAF slag in removing P from a given stormwater system. It was also established that a number of combinations of these factors influence P uptake differently.

  16. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

    Massoudi, Mehrdad [National Energy Technology Laboratory; Wang, Ping


    The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.

  17. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

    Mehrdad Massoudi


    Full Text Available The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.

  18. Laser yellowing

    M B Sai Prasad; Salvatore Siano


    Over the past few years there has been an increasing interest in researches related to the application of lasers in conservation, analysis and diagnostics of artwork surfaces. Among the many interesting problems to be tackled, one issue was drawing more interest because of the limitations it can impose on the use of lasers. Laser yellowing is a phenomenon wherein artwork surfaces assume a yellow hue when cleaned with Q-switched Nd:YAG (1064 nm) lasers in particular. Here the effect of yellowing has been studied and quantified for artwork surfaces (marble) using SFR Nd:YAG and LQS Nd:YAG lasers. Colorimetric measurements by employing a spectroradiometer helps to quantify the effect of yellowing by analysing three variables (chromaticity coordinates) of interest.

  19. Understanding Slag Freeze Linings

    Fallah-Mehrjardi, Ata; Hayes, Peter C.; Jak, Evgueni


    Slag freeze linings, the formation of protective deposit layers on the inner walls of furnaces and reactors, are increasingly used in industrial pyrometallurgical processes to ensure that furnace integrity is maintained in these aggressive, high-temperature environments. Most previous studies of freeze-linings have analyzed the formation of slag deposits based solely on heat transfer considerations. These thermal models have assumed that the interface between the stationary frozen layer and the agitated molten bath at steady-state deposit thickness consists of the primary phase, which stays in contact with the bulk liquid at the liquidus temperature. Recent experimental studies, however, have clearly demonstrated that the temperature of the deposit/liquid bath interface can be lower than the liquidus temperature of the bulk liquid. A conceptual framework has been proposed to explain the observations and the factors influencing the microstructure and the temperature of the interface at steady-state conditions. The observations are consistent with a dynamic steady state that is a balance between (I) the rate of nucleation and growth of solids on detached crystals in a subliquidus layer as this fluid material moves toward the stagnant deposit interface and (II) the dissolution of these detached crystals as they are transported away from the interface by turbulent eddies. It is argued that the assumption that the interface temperature is the liquidus of the bulk material represents only a limiting condition, and that the interface temperature can be between T liquidus and T solidus depending on the process conditions and bath chemistry. These findings have implications for the modeling approach and boundary conditions required to accurately describe these systems. They also indicate the opportunity to integrate considerations of heat and mass flows with the selection of melt chemistries in the design of future high temperature industrial reactors.

  20. Phosphorus, Agriculture & The Environment

    Mullins, Gregory Lee


    Discusses potential environmental impacts of phosphorus, the functions of phosphorus in plants and animals, and the soil phosphorus cycle. Notes methods for controlling phosphorus losses to surface waters

  1. Overview of Steel Slag Application and Utilization

    Lim J.W.


    Full Text Available Significant quantities of steel slag are generated as waste material or byproduct every day from steel industries. Slag is produced from different types of furnaces with different operating conditions. Slag contains Ferrous Oxide, Calcium Oxide, Silica etc. Physical and chemical properties of slag are affected by different methods of slag solidification such as air cooled, steam, and injection of additives. Several material characterization methods, such as X-ray Diffraction (XRD, Scanned Electron Microscopy (SEM and Inductive Coupled Plasma (ICP-OES are used to determine elemental composition in the steel slag. Therefore, slags can become one of the promising materials in various applications such as in transportation industry, construction, cement production, waste water and water treatment. The various applications of steel slag indicate that it can be reused and utilized rather than being disposed to the landfill. This paper presents a review of its applications and utilization.

  2. Coal Slag Attack-A Review

    GUO Zongqi


    Although slagging coal gasifiers have served the commercial systems of electricity and chemical fertilizer productions for more than ten years, refractory service life still is a critical factor for gasifier availability. Some investigations were attracted, focusing on coal slag attack on high chromia refractories. A general introduction is made in order to have further understanding about slag corrosion in coal gasification environment. Microstructural deterioration and wear process of high chromia refractory in slagging gasifiers are discussed.

  3. Viscosity estimation for slags containing calcium fluoride

    Qifeng Shu; Jiayun Zhang


    Based on recently published experimental data, the Riboud model was modified for viscosity estimation of the slags containing calcium fluoride. The estimated values were in good agreement with measured data. Reasonable estimation can be achieved using the modified Riboud model for mould fluxes and ESR (eletro slag remelting) slags. Especially for ESR slags, the modified Riboud model can provide much more precise values than the original Riboud model.

  4. Mineral resource of the month: ferrous slag



    The article offers information on mineral resource ferrous slag. Ferrous slag is produced through the addition of materials such as limestone and dolomite to blast and steel furnaces to remove impurities from iron ore and to lower the heat requirements for processes in iron and steel making. It is stated that the method of cooling is important for the market uses and value of ferrous slag. Some types of slag can be used in construction, glass manufacturing and thermal insulation.

  5. Melting Behaviour of Ferronickel Slags

    Sagadin, Christoph; Luidold, Stefan; Wagner, Christoph; Wenzl, Christine


    The industrial manufacturing of ferronickel in electric furnaces produces large amounts of slag with strong acidic character and high melting points, which seriously stresses the furnace refractory lining. In this study, the melting behavior of synthetically produced ferronickel slags on magnesia as refractory material was determined by means of a hot stage microscope. Therefore, slags comprising the main oxides SiO2 (35-70 wt.%), MgO (15-45 wt.%) and Fe2O3 (5-35 wt.%) were melted in a graphite crucible and afterwards analyzed by a hot stage microscope. The design of experiments, which was created by the statistic software MODDE®, included 20 experiments with varying slag compositions as well as atmospheres. The evaluation of the test results occurred at three different characteristic states of the samples like the softening point according to DIN 51730 and the temperatures at which the area of residual cross-section of the samples amounted to 30% and 40%, respectively, of the original value depending of their SiO2/MgO ratio and iron oxide content. Additionally, the thickness of the zone influenced by the slag was measured and evaluated.

  6. Smelting Oxidation Desulfurization of Copper Slags

    LI Lei; HU Jian-hang; WANG Hua


    According to the mechanism of sulfur removal easily through oxidation, the process of smelting oxidation desulfurization of copper slags is studied, which supplies a new thinking for obtaining the molten iron of lower sulfur content by smelting reduction of copper slags. Special attention is given to the effects of the holding temperature, the holding time and CaF2, CaO addition amounts on the desulfurization rate of copper slags. The results indicate that the rate of copper slags smelting oxidation desulfurization depends on the matte mass transfer rate through the slag phase. After the oxidation treatment, sulfur of copper slags can be removed as SO2 efficiently. Amount of Ca2+ of copper slags affects the desulfurization rate greatly, and the slag desulfurization rate is reduced by adding a certain amount of CaF2 and CaO. Compared with CaF2, CaO is negative to slags sulfur removal with equal Ca2+ addition. Under the air flow of 0.3 U/min, the sulfur content of copper slags can be reduced to 0. 004 67% in the condition of the holding time of 3 min and the holding temperature of 1 500 ℃. The sulfur content of molten iron is reduced to 0. 000 8 % in the smelting reduction of treated slags, and the problem of high sulfur content of molten iron obtained by smelting reduction with copper slag has been successively solved.



    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  8. Yellow fever

    Prata Aluízio


    Full Text Available With the infestation by Aedes aegypti, urban yellow fever might already exist. This did not occur because of either the lacking of a sufficient contact between the diseased individual and the A. aegypti or perhaps because this, after sixty years without transmitting the virus, needs an adaptation phase to infecting again.

  9. Slags in steel making; Kuonat teraeksen valmistuksessa

    Haerkki, J.; Paeaetalo, M.; Karhu, P.; Jauhiainen, A.; Alamaeki, P.; Koski-Laine, S.; Ollila, J. [Oulu Univ. (Finland). Dept. of Process Engineering


    At the first step of the project all stages of the steelmaking processes were viewed from the blast furnace to the continuous casting. Slag knowledge of each processes were collected into a guide, which is meant to help both production and research. At the same time the essential problems caused by slags in steelmaking were focused. At the second step the focus of this slag-project were transferred into the desulphurization, converter, ladle and tundish slags. Wide slag knowledge has been divided into smaller parts and applied versatile into the steelmaking process taking into account the metallurgical, economical and qualitative aspects. (orig.) SULA 2 Research Programme; 13 refs.

  10. AISI/DOE Technology Roadmap Program: Behavior of Phosphorus in DRI/HBI During Electric Furnace Steelmaking

    Richard J. Frueham; Christopher P. Manning


    Many common scrap substitutes such as direct reduced iron pellets (DRI), hot briquetted iron (HBI), iron carbide, etc., contain significantly higher levels of phosphorus steelmaking for the production of higher quality steels, control of phosphorus levels in the metal will become a concern. This study has developed a more complete understanding of the behavior of phosphorus in DRI during EAF steelmaking, through a thorough investigation of the kinetics and thermodynamics of phosphorus transfer in the EAF based upon laboratory and plant experiments and trials. Laboratory experiments have shown that phosphorus mass transfer between oxide and metallic phases within commercial direct reduced iron pellets occurs rapidly upon melting according to the local equilibrium for these phases. Laboratory kinetic experiments indicate that under certain conditions, phosphorus mass transfer between slag and metal is influenced by dynamic phenomena, which affect the mass transfer coefficient for the reaction and/or the slag metal interfacial area. Plant trials were conducted to directly evaluate the conditions of mass transfer in the electric furnace and to determine the effects of different scrap substitute materials upon the slag chemistry, the behavior of phosphorus in the steel, and upon furnace yield. The data from these trials were also used to develop empirical models for the slag chemistry and furnace temperature as functions of time during a single heat. The laboratory and plant data were used to develop a numerical process model to describe phosphorus transfer in the EAF


    V. F. Sobolev


    Full Text Available The analysis of thermodynamic models, which can be used for calculation of phosphorus allocation in the process of melting in steel-making furnace, is presented. It is shown, that temperature of melting process, basic capacity and oxidability of slag mixture in furnace influence to a greatest extent on allocation of phosphorus.

  12. Study on cementitious properties of steel slag

    Zhu G.


    Full Text Available The converter steel slag chemical and mineral components in China’s main steel plants have been analysed in the present paper. The electronic microscope, energy spectrum analysis, X-ray diffraction analysis confirmed the main mineral compositions in the converter slag. Converter slag of different components were grounded to obtain a powder with specific surface area over 400m2/kg, making them to take place some part of the cement in the concrete as the admixture and carry out the standard tests. The results indicate that the converter slag can be used as cementitious materials for construction. Furthermore, physical mechanic and durability tests on the concrete that certain amount of cement be substituted by converter steel slag powder from different steel plants are carried out, the results show that the concrete with partial substitution of steel slag powder has the advantages of higher later period strength, better frost resistance, good wear resistance and lower hydration heat, etc. This study can be used as the technical basis for “Steel Slag Powder Used For Cement And Concrete”, “Steel Slag Portland Cement”, “Low Heat Portland Steel Slag Cement”, “Steel Slag Road Cement” in China, as well as a driving force to the works of steel slag utilization with high-value addition, circular economy, energy conservation and discharge reduction in the iron and steel industry.

  13. Mass transfer of phosphorus in high-phosphorus hot-metal refining

    Jiang Diao; Xuan Liu,; Tao Zhang; Bing Xie


    Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO−FetO−SiO2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall mass transfer coefficient, which includes the effects of mass transfer in both the slag phase and metal phase, is in the range of 0.0047 to 0.0240 cm/s. With the addition of a small amount of fluxing agents Al2O3 or Na2O into the slag, the overall mass transfer coefficient has an obvious increase. Silicon content in the hot metal also influences the overall mass transfer coefficient. The overall mass transfer coefficient in the lower [Si] heat is much higher than that in the higher [Si] heat. It is concluded that both fluxing agents and lower [Si] hot metal facilitate mass transfer of phosphorus in liquid phases. Fur-thermore, the addition of Na2O could also prevent rephosphorization at the end of the experiment.

  14. Simultaneous Recovery of Iron and Phosphorus from a High-Phosphorus Oolitic Iron Ore to Prepare Fe-P Alloy for High-Phosphorus Steel Production

    Yang, Congcong; Zhu, Deqing; Pan, Jian; Lu, Liming


    Unlike previous dephosphorization studies, the present work complies with a concept to recover phosphorus within the utilization of high-phosphorus oolitic iron ores to prepare Fe -P alloy for high-phosphorus steel production. Simultaneous enrichment of iron and phosphorus can be achieved by directly alloying the high-phosphorus oolitic iron ore at high reduction temperatures (≥1623 K). Neither fluxes nor other special additives need to be used. Consequently, the phosphorus element migrates from original apatite to the slag phase with the elevating temperature from 1323 K to 1473 K, and it further moves into metallic iron and forms Fe3P at 1623 K. A metalized iron -phosphorus alloy with assaying of 96.51% iron and 2.03% phosphorus content was obtained at 1623 K for 10 min at corresponding iron and phosphorus recovery rates of 97.50% and 64.51%, respectively. This process exhibits high economic efficiency and is practicable as a stepping-stone for the efficient and direct utilization of high-phosphorus iron ore resources.

  15. Difference in BOF Slag Splashing in US and China


    Some differences in slag splashing between BOF steel works in USand China were investigated. The slag composition, melting point, and mineralogical phases of final slags from both countries were studied. The control of slag superheat is important to an effective slag coating.

  16. The Sulfide Capacity of Iron Oxide-Rich Slags

    Motlagh, M.


    The relationship between the sulfide capacity of slags rich in iron oxide and the sulfur partition ratio between the metal and slag is strongly related to the slag's iron oxide concentration. For slags containing little or no lime, this relationship is linear for a constant concentration of iron oxide in the slag. The effect of silica on changes in the sulfide capacity of slags rich in iron oxide is similar to that of basic steel-making slags, particularly at low activity of silica in slag.

  17. Steel desulphurization with synthetic slag

    Heput, T.


    Full Text Available Generally speaking, sulphur is considered a harmful element for steel quality, reason why all the technological steps are being taken in order to eliminate it from the metal bath. This paper deals with the influence of the chemical composition, on the slag quantity and of the bath stirring condition upon the desulphurization process in the casting ladle by treatment with synthetic slag. The experiments were made at an open-hearth plant with the steel tapping in two ladles (the desulphurization was made with synthetic slag at one ladle while the other one was considered standard and at the electric steel plant and for the synthetic slag formation a mix was used, made, according to several receipts, of: lime (50-75%, fluorine (0-17%, bauxite (0-32% and aluminous slag (8-22%. The data were processed in the calculation programs EXCEL and MATLAB, which resulted in a series of correlations between the desulphurization degree and the chemical composition of the slag, respectively the slag quantity both for the charges bubbled with Argon and the unbubbled ones.

    En general, el azufre es considerado un elemento nocivo para la calidad del acero y, por eso, en la práctica, se toman todas las medidas de orden tecnológico para su eliminación del baño metálico. En este trabajo se analiza la influencia de la composición química, de la cantidad de escoria y del estado de agitación del baño sobre el proceso de desulfuración en la cuchara para fundir por tratamiento con escoria sintética. Los experimentos se han realizado en una acería evacuando el acero en dos ollas (en una cuchara se efectuó la desulfuración con escoria sintética y a la otra se consideró como patrón y en un acería eléctrica y para la formación de la escoria sintética se utilizó una mezcla producida según muchas recetas, formada por: cal (50-75%, fluorina (0-17%, bauxita (0-32% y escoria aluminosa (8-22%. Los datos han sido procesados en los programas de c

  18. The use of blast furnace slag

    V. Václavík


    Full Text Available The paper presents the results of experimental research that dealt with the substitution of finely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on finely ground blast furnace slag were observed.

  19. The use of blast furnace slag

    V. Václavík; V. Dirner; T. Dvorský; J. Daxner


    The paper presents the results of experimental research that dealt with the substitution of finely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on finely ground blast furnace slag were observed.

  20. Performance study of vegetated sequencing batch coal slag bed treating domestic wastewater in suburban area

    Chan, S.Y.; Tsang, Y.F.; Chua, H.; Sin, S.N.; Cui, L.H. [Hong Kong Polytechnic University, Hong Kong (China)


    A practical and affordable wastewater treatment system serving small community in suburban areas was studied. The system was a vegetated sequencing batch coal slag bed integrated with the rhythmical movement of wastewater and air like that of a sequencing batch reactor. The removal mechanisms capitalized on the pollutant removal process in conventional constructed wetland. Cyperus alternifolius was planted into the coal slag bed to form a novel plant-soil-microbial interactive system. Nutrients in the domestic wastewater, which cause environmental nuisance like eutrophication, were targeted to be eliminated by the process design. Operated with the contact time of 18 h, the treatment systems achieved around 60% removal efficiency for carbonaceous matters. The removals of ammonia nitrogen and phosphorus were about 50% and 40%, respectively, while the removal of total suspended solids was approaching 80%. From the current study.. the construction cost of the vegetated sequencing batch coal slag bed was 256 RMB/m{sup 3} and the operation cost was 0.13 RMB/m{sup 3}. With the advantages of ease of operation, low costs, desirable treatment efficiency and aesthetic value, the vegetated sequencing batch coal slag bed is proposed to be an alternative for onsite domestic wastewater treatment in suburban areas.

  1. 盐酸介质磷钒钼黄直接光度法快速测定钒浸出液中的磷%Rapid phosphorus analysis in vanadium- leached solution using direct absorbance measurement in hydrochloric acid media phosphorus - vanadium - molybdenum yellow system

    刘继宁; 马庆; 刘忠文; 党岚


    Compared with analytical characteristics and interfering factors for different media, hydrochloric acid was chosen as media in direct absorbance measurement to analyse phosphorus of Vanadium - leached solution.In this method, ammonium sodium was chosen as chromogenic agent, under the conditions that: the coloration acidity is 1.2 N, λ = 430 nm, ε = 1 300. We concluded that when phosphorus content is between 0 ~ 400 μg,Beer' s law is obeyed; when phosphorus content is lower limit 1.67 μg(3s), the coexistence components don' t interfere with phosphorus; when phosphorus content is 50 ~ 350 μg, the adding standard sample rate of recovery is 97.76% ~ 102. 1%; when phosphorus content is 100 μg, eleven times analyses are made and given. RSD =1.52% and X = 100. 48 μ-g.%研究了不同介质中钒钼黄法的分析特性和干扰因素,选定盐酸介质建立了快速分析钒浸出液中磷的直接光度法.该方法用钼酸钠作显色剂,显色酸度1.2 N,λ=430 nm,ε=1300,0~400μg线性良好;检测下限1.67μg(3s),共存组分无干扰,50~350μg加标回收率97.6%~102.1%,100μg中重复11次分析,RSD=1.52%,X=100.48μg.

  2. Picture analysing method of slag foaming behaviour

    Juhart, M.; Peter, M.; Koch, K. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Metallurgy; Lamut, J. [Faculty of Natural Science and Technology, Univ. Ljubljana, Ljubljana (Slovenia)


    Hot tests of foaming behaviour of steelmaking slags were conducted on a laboratory scale up to 1760 C using a Tammann furnace. The foaming behaviour of the slags was quantified on the basis of a new measuring method. The volume increase and the progress of the foaming process can be continuously observed and calculated by means of picture analysis. The gas content of foaming slags was compared with the results of the measurements performed in steel plants. The influence of the magnesia content on the foaming behaviour is investigated. The chemical composition of the slag is beside the CO evolution the decisive factor influencing slag foaming behaviour. The highest volume increase values observed lie in the region of 2500% in relation to the initial volume. (orig.)

  3. Leaching of heavy metals from steelmaking slags

    Gomez, J. F. P.; Pino, C. G.


    Leaching tests with EAF and Ladle slags were performed, using a flow through tests 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, and 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, slang samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-though 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). (Author) 12 refs.

  4. Gravitational segregation of liquid slag in large ladle

    J. Chen


    Full Text Available The process of gravitational segregation makes liquid steel slag components occur differentiation. And it shows that the upper part slag in the slag ladle contains higher CaO; and the lower part slag contains higher SiO2. The content of MgO (5,48 % in the upper part slag is higher than that of the lower part (2,50 %, and only Al2O3 content of the upper and the lower part slag is close to each other. The difference of chemical compositions in the slag ladle shows that there is gravitational segregation during slow solidification of liquid steel slag, which will has some impact of the steel slag processing on the large slag ladle.

  5. A numerical model for chemical reaction on slag layer surface and slag layer behavior in entrained-flow gasifier

    Liu Sheng


    Full Text Available The paper concerns with slag layer accumulation, chemical reaction on slag layer surface, and slag layer flow, heat and mass transfer on the wall of entrained-flow coal gasifier. A slag layer model is developed to simulate slag layer behaviors in the coal gasifier. This 3-D model can predict temperature, slag particle disposition rate, disposition particle composition, and syngas distribution in the gasifier hearth. The model is used to evaluate the effects of O2/coal ratio on slag layer behaviors.

  6. Study of decomposing carbonyl slag

    CHEN Ai-liang; SUN Pei-mei; ZHAO Zhong-wei; LI Hong-gui; CHEN Xing-yu


    A new technology was put forward to deal with the carbonyl slag at low acidity and low oxygen pressure in the kettle.With the orthogonal experiments for analyzing the sequence of four factors and some single factor experiments for the best conditions. The best conditions are used for extracting nickel, cobalt and copper and enriching precious metals: the cupric ion concentration is 5 g/L; and pH=6; the sulfur coefficient is 1.4; the oxygen pressure is 0.08 MPa; the time bubbling oxygen is 20 min;the ratio of liquid to solid is 8:1; the leaching time is 2 h; the heating time is 2.5 h. The leaching rates of nickel and cobalt are more than 98% and that of copper is above 97%. Nickel and cobalt can be separated efficiently from copper and precious metals from the carbonyl slag. Moreover, its leaching liquor has less copper. Nickel and cobalt can be reclaimed only once. During the whole process,the leaching rates of Au and Ag are more than 99.9%, while other precious metals are still in the residue without any loss.

  7. Hydrothermal synthesis of xonotlite from carbide slag

    Jianxin Cao; Fei Liu; Qian Lin; Yu Zhang


    Carbide slag was used as the calcareous materials for the first time to prepare xonotlite via dynamic hydrothermal synthesis.The effects of influential factors including different calcination temperatures,pretreatment methods of the carbide slag and process param-eters of hydrothermal synthesis on the microstructure and morphology of xonotlite were explored using XRD and SEM techniques.The results indicate that the carbide slag after proper calcination could be used to prepare pure xonotlite;and different calcination tern-peratures have little effect on the crystallinity of synthesized xonotlitc,but have great impact on the morphology of secondary particles.The different pretreatment methods of the carbide slag pose great impact on the crystallinity and morphology of secondary particles of xonotlite.Xonotlite was also synthesized from pure CaO under the salne experimental conditions as that prepared from calcined carbide slag for comparison.Little amount of impurities in carbide slag has no effect on the mechanism of hydrothermal synthesizing xonotlite from carbide slag.

  8. Coexistence Theory of Slag Structure and Its Application to Calculation of Oxidizing Capability of Slag Melts


    The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculation of oxidizing capabilities of slag melts in combination with the coexistence theory of slag structure.For slag melts containing basic oxides FeO and MnO, their oxidizing capabilities can be expressed by NFetO=NFeO+6NFe2O3, while for slag melts containing basic oxides CaO, MgO, etc., in addition to FeO and MnO, their oxidizing capabilities can be given as NFetO=NFeO+6NFe2O3+8NFe3O4.

  9. Novel Sessile Drop Software for Quantitative Estimation of Slag Foaming in Carbon/Slag Interactions

    Khanna, Rita; Rahman, Mahfuzur; Leow, Richard; Sahajwalla, Veena


    Novel video-processing software has been developed for the sessile drop technique for a rapid and quantitative estimation of slag foaming. The data processing was carried out in two stages: the first stage involved the initial transformation of digital video/audio signals into a format compatible with computing software, and the second stage involved the computation of slag droplet volume and area of contact in a chosen video frame. Experimental results are presented on slag foaming from synthetic graphite/slag system at 1550 °C. This technique can be used for determining the extent and stability of foam as a function of time.

  10. Slags from steel production: Properties and their utilization

    J. Vlcek


    Full Text Available During steel production a considerable amount of slags is produced. In addition to its usual processing, as recycling in device for steel production and preparation of aggregates, it is also possible to apply less common slag processing ways. Depending on cooling mode of the steel slags these may show some binding properties. Geopolymer type binders can be prepared from the slag using alkali activators or the hydraulic properties of the dicalciumsilicate present in the slag can be induced by water. The paper summarizes present state of material utilisation of the steel slags with focus on emphasize of the possible sources of the slag volume instability. The influence of process of slag cooling on its phase composition is documented. It was also found that slags from real sources show different parameters compared to samples obtained for laboratory examination.

  11. Settling of copper drops in molten slags

    Warczok, A.; Utigard, T. A.


    The settling of suspended metal and sulfide droplets in liquid metallurgical, slags can be affected by electric fields. The migration of droplets due to electrocapillary motion phenomena may be used to enhance the recovery of suspended matte/metal droplets and thereby to increase the recovery of pay metals. An experimental technique was developed for the purpose of measuring the effect of electric fields on the settling rate of metallic drops in liquid slags. Copper drops suspended in CaO-SiO2-Al2O3-Cu2O slags were found to migrate toward the cathode. Electric fields can increase the settling rate of 5-mm-diameter copper drops 3 times or decrease the settling until levitation by reversal of the electric field. The enhanced settling due to electric fields decreases with increasing Cu2O contents in the slag.

  12. Electroreduction Kinetics for Molten Oxide Slags

    GAO Yun-ming; CHOU Kuo-chih; GUO Xing-min; WANG Wei


    The oxygen-ion conductor, the reducing agent, and the molten oxide slag containing electroactive matter were used as constituent of a galvanic cell. Metal was directly electroreduced from molten slag using a short-circuit galvanic cell. The following galvanic cell was assembled in the present experiment: graphite rod, [O]Fe-C saturated|ZrO2(MgO)|Cu(l)+(FeO)(slag), and molybdenum wire. The FeO electroreduction reaction was studied through measuring short circuit current by controlling factors such as temperature, the FeO content in molten slags, and the external circuit resistance. An overall kinetics model was developed to describe the process of FeO electroreduction. It was found that the modeled curves were in good agreement with the experimental values. The new oxide reduction method in the metallurgy with controlled oxygen flow was proposed and the metallurgical theory with controlled oxygen flow was developed.

  13. Acid slag injection into the blast furnace tuyere zone

    Haerkki, J.; Tervola, K. [Oulu Univ. (Finland). Dept. of Process Engineering


    The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

  14. Sulfide capacities of fayalite-base slags

    Simeonov, S. R.; Sridhar, R.; Toguri, J. M.


    The sulfide capacities of fayalite-base slags were measured by a gas-slag equilibration technique under controlled oxygen and sulfur potentials similar to those encountered in the pyrometallurgical processing of nonferrous metals. The oxygen pressure range was from 10-9.5 to 10-11 MPa and the sulfur pressure range from 10-3 to 10-4.5 MPa, over a temperature range of 1473 to 1623 K. The slags studied were FeO-SiO2 at silica saturation and those with addition of CaO, MgO, and Al2O3 to determine their effect on sulfide capacities. For these slags, the sulfide capacities were found to vary from 10-3.3 to 10-5. The sulfide capacities increased with increasing temperature from 1473 to 1623 K. A comparison of the reported plant data on sulfur content of industrial slags shows good agreement with the present experimental results. The present data will be useful in estimating metal losses in slag due to metal sulfide entrainment in nonferrous smelters.

  15. Calculation of sulfide capacities of multicomponent slags

    Pelton, Arthur D.; Eriksson, Gunnar; Romero-Serrano, Antonio


    The Reddy-Blander model for the sulfide capacities of slags has been modified for the case of acid slags and to include A12O3 and TiO2 as components. The model has been extended to calculate a priori sulfide capacities of multicomponent slags, from a knowledge of the thermodynamic activities of the component oxides, with no adjustable parameters. Agreement with measurements is obtained within experimental uncertainty for binary, ternary, and quinary slags involving the components SiO2-Al2O3-TiO2-CaO-MgO-FeO-MnO over wide ranges of composition. The oxide activities used in the computations are calculated from a database of model parameters obtained by optimizing thermodynamic and phase equilibrium data for oxide systems. Sulfur has now been included in this database. A computing system with automatic access to this and other databases has been developed to permit the calculation of the sulfur content of slags in multicomponent slag/metal/gas/solid equilibria.

  16. Residue formations of phosphorus hydride polymers and phosphorus oxyacids during phosphine gas fumigations of stored products.

    Flora, Jason W; Byers, Loran E; Plunkett, Susan E; Faustini, Daryl L


    With the extent of international usage and the critical role phosphine gas (PH3) plays in commercial pest control, identification of the residual components deposited during fumigation is mandatory. It has been postulated that these infrequent residues are primarily composed of phosphoric acid or reduced forms of phosphoric acid [hypophosphorous acid (H3PO2) and phosphorous acid (H3PO3)], due to the oxidative degradation of phosphine. Using environmental scanning electron microscopy, gas phase Fourier transform infrared spectroscopy, and X-ray fluorescence spectroscopy, the structural elucidation and formation mechanism of the yellow amorphous polyhydric phosphorus polymers (P(x)H(y)) that occur in addition to the lower oxyacids of phosphorus in residues deposited during PH3 fumigations of select tobacco commodities are explored. This research determined that nitric oxide gas (or nitrogen dioxide) initiates residue formation of phosphorus hydride polymers and phosphorus oxyacids during PH3 fumigations of stored products.

  17. Phytoextraction of excess soil phosphorus

    Sharma, Nilesh C. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Starnes, Daniel L. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Sahi, Shivendra V. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States)]. E-mail:


    In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species. - Crop plants such as cucumber, squash and sunflower accumulate phosphorus and thus can be used in the phytoextraction of excess phosphorus from soils.

  18. Phosphorus removal from secondary effluents through integrated constructed treatment system.

    Xiong, Jibing; Qin, Yong; Mahmood, Qaisar; Liu, Hanhu; Yang, Dejun


    The treatment capacity of an integrated constructed treatment system (CTS) was explored which was designed to reduce phosphorus (P) from secondary effluents. The integrated CTS was combined with vertical-flow constructed wetland, floating bed and sand filter. The vertical wetland was filled from the bottom to the top with gravels, steel slag and peat. Vetiverzizanioides (L.) Nash was selected to grow in the vertical constructed wetland while Coixlacrymajobi L. was grown in floating bed. The results suggested that integrated CTS displayed excellent removal efficiency for chemical oxygen demand (COD), dissolved phosphorus (DP), and total phosphorus (TP). The average COD removal efficiency of the integrated CTS was 90.45% after 40 days of operation, the average DP and TP removal efficiencies of the integrated CTS were 97.43% and 96.40%, respectively. The integrated CTS has good potential in removing COD as well as P from secondary effluents. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Heat Flux Through Slag Film and Its Crystallization Behavior

    TANG Ping; XU Chu-shao; WEN Guang-hua; ZHAO Yan-hong; QI Xin


    An experimental apparatus for simulating copper mold is used to quantify the heat flux through the slag film and to obtain a solid slag for further determining its crystallization behavior.The result indicates that both the chemical composition of the mold powder and the cooling rate have an important influence on the heat flux through the slag film.With increasing the binary hasicity,the heat flux of slag film decreases at first,reaches the minimum at the basicity of 1.4,and then increases,indicating that the maximum binary basicity is about 1.4 for selecting"mild cooling"mold powder.The heat transfer through the slag film can be specified in terms of the crystalline ratio and the thickness of the slag film.Reerystallization of the solid slag occurs and must be considered as an important factor that may influence the heat transfer through the solid slag layer.

  20. Osmundiron, cleaved iron bars and slags (Osmundjern, kloder og kalotslagger)

    Buchwald, Vagn Fabritius


    Investigation of so-called Osmund iron, iron bars and slags from iron production in the medieval ages.......Investigation of so-called Osmund iron, iron bars and slags from iron production in the medieval ages....

  1. 'Active' filters for upgrading phosphorus removal from pond systems.

    Shilton, A; Pratt, S; Drizo, A; Mahmood, B; Banker, S; Billings, L; Glenny, S; Luo, D


    This paper investigates limestone and iron slag filters as an upgrade option for phosphorus removal from wastewater treatment ponds. A review of 'active' filter technology and the results from laboratory and field research using packed columns of the different media is presented. It is shown that both limestone and iron slag can remove phosphorus but highlights that different types of limestone give markedly different performance. Filter performance appears to be improved by increasing temperature and by the presence of algae, presumably because of its tendency to elevate pH. Performance is related to hydraulic retention time (HRT), but this relationship is not linear, particularly at low HRTs. Importantly for future research, the results from field-testing with pond effluent show significant differences compared to those obtained when using a synthetic feed in the laboratory. For the iron slag filter, higher performance was observed in the field (72% in field vs. 27% in laboratory, at a 12 hour-HRT), while the opposite was observed for the limestone (64% in laboratory vs. 18% in field, at a 12-hour HRT).

  2. Recycling and valorisation of stainless steel slags

    Van Dessel, J. [Belgian Building Research Institute, Brussels (Belgium)


    The project described in this paper involves the collaboration of eleven partners. The project aims to create a value-added product by recovering usable non-ferrous metals from the production of stainless steel and use the recycled slag as a secondary material for road construction and concrete applications. The objective of the project is to return the metal contained in the slag to stainless steel production, and to treat the non-metallic slag, perhaps by a metallurgical process based upon direct plasma technology, prior to use in a variety of processes. The project also aims to investigate the environmental characteristics of the slag, which is essential for it to be used as secondary material. The major challenge appears to be the development of an improved process for separating the slag from the metallic particles in order to avoid the frequent breakdowns and significant repairs associated with use of the material. It is expected that using magnetic and density-based separation processes will reduce the cost of maintenance by about 20 per cent. Results achieved to date, and economic factors impacting on feasibility, are also discussed. 2 tabs., 3 figs.

  3. Process-integrated slag treatment; Prozessintegrierte Schlackebehandlung

    Koralewska, R.; Faulstich, M. [Technische Univ., Garching (Germany). Lehrstuhl fuer Wasserguete- und Abfallwirtschaft


    The present study compares two methods of washing waste incineration slag, one with water only, and one which uses additives during wet deslagging. The presented aggregate offers ideal conditions for process-integrated slag treatment. The paper gives a schematic description of the integrated slag washing process. The washing liquid serves to wash out the readily soluble constituents and remove the fines, while the additives are for immobilising heavy metals in the slag material. The study is based on laboratory and semi-technical trials on the wet chemical treatment of grate slag with addition of carbon dioxide and phosphoric acid. [Deutsch] Die dargestellten Untersuchungen beziehen sich auf den Vergleich zwischen einer Waesche der Muellverbrennungsschlacke mit Wasser und unter Zugabe von Additiven im Nassentschlacker. In diesem Aggregat bieten sich optimale Voraussetzungen fuer eine prozessintegrierte Schlackebehandlung. Die Durchfuehrung der integrierten Schlackewaesche wird schematisch gezeigt. Durch die Waschfluessigkeit sollen die leichtloeslichen Bestandteile ausgewaschen und die Feinanteile ausgetragen sowie durch die Additive zusaetzlich die Schwermetalle im Schlackematerial immobilisiert werden. Dazu erfolgten Labor- und halbtechnische Versuche zur nasschemischen Behandlung der Rostschlacken unter Zugabe von Kohlendioxid und Phosphorsaeure. (orig./SR)

  4. Use of slag for dye removal

    Ramakrishna, K.R.; Viraraghavan, T. [Univ. of Regina, Saskatchewan (Canada). Faculty of Engineering


    Adsorption techniques employing activated carbon have been found to be reasonably effective in the removal of some of the ionic impurities in water. However, economic considerations may require the use of inexpensive sorbents which are either naturally available or available as waste products from manufacturing processes. Slag is one such waste product obtained during the manufacture of steel, and the present study investigates dye removal characteristics of slag from colored waters. Aqueous solutions prepared from commercial grade acid, basic, and disperse dyes were used in this study, and batch pH, kinetic, and isotherm studies were undertaken on a laboratory scale. The data were evaluated for applicability to the Langmuir, Freundlich, and BET isotherm models, and the removal capacity of slag was compared with that of granular activated carbon. Results indicated approximately 94% removal of the disperse dye by slag, compared with a removal of approximately 49% achieved by activated carbon. Removal of acid dyes (dyes containing anionic groups) was reasonably good (approximately 47 and 74%), though not as good as obtained using activated carbon (approximately 100%). Column studies were conducted with a disperse dye (nonionic, slightly soluble in water), and analysis of data showed a sorption capacity of 1.3 mg of disperse dye per gram of slag. However, effluent dye concentrations were found to be higher than the permissible levels for discharge to receiving waters.

  5. X-ray fluoroscopic observation of slag foaming; Slag no awadachi gensho no x sen toshi kansatsu

    Ogawa, Y.; Tokumitsu, N. [Nippon Steel Corp., Tokyo (Japan)


    Slag foaming caused by slag/metal reaction in a graphite crucible was observed with X-ray fluoroscopic apparatus in order to make clear the effect of bubble size on the foam height and the distribution of bubbles in slag. It was observed that the foam layer was formed when CO bubbles evolved at slag/metal interface became less than approximately 2mm in diameter. The foam height increased with the decrease of bubble size even in case of almost the same gas evolution rate. The size of bubbles decreased with the increase of iron oxide Content in slag and the decrease of sulphur content. It is considered that the bubbles become smaller when slag is wettable with metal. Therefore, the physical properties of slag/metal interface also affect the foam height besides the surface tension or viscosity of slag because they change the bubble size. (author)

  6. Use of blast furnace granulated slag as a substrate in vertical flow reed beds: field application.

    Asuman Korkusuz, E; Beklioğlu, Meryem; Demirer, Göksel N


    Research was conducted at Middle East Technical University (METU), Ankara, Turkey in 2000 to determine whether a reed bed filled with an economical Turkish fill media that has high phosphorus (P) sorption capacity, could be implemented and operated successfully under field conditions. In batch-scale P-sorption experiments, the P-sorption capacity of the blast furnace granulated slag (BFGS) of KARDEMIR Iron and Steel Ltd., Co., Turkey, was found to be higher compared to other candidate filter materials due to its higher Ca content and porous structure. In this regard, a vertical subsurface flow constructed wetland (CW) (30 m(2)), planted with Phragmites australis was implemented at METU to treat primarily treated domestic wastewater, at a hydraulic rate of 100 mm d(-1), intermittently. The layers of the filtration media constituted of sand, BFGS, and gravel. According to the first year monitoring study, average influent and effluent total phosphorus (TP) concentrations were 6.61+/-1.78 mg L(-1) and 3.18+/-1.82 mg L(-1); respectively. After 12 months, slag samples were taken from the reed bed and P-extraction experiments were performed to elucidate the dominant P-retention mechanisms. Main pools for P-retention were the loosely-bounded and Ca-bounded P due to the material's basic conditions (average pH>7.7) and higher Ca content. This study indicated the potential use of the slag reed bed with higher P-removal capacity for secondary and tertiary treatment under the field conditions. However, the P-sorption isotherms obtained under the laboratory conditions could not be used favorably to determine the longevity of the reed bed in terms of P-retention.

  7. Dietary phosphorus, serum phosphorus, and cardiovascular disease.

    Menon, Madhav C; Ix, Joachim H


    Recent epidemiologic studies have linked higher serum phosphorus concentrations to cardiovascular disease (CVD) events and mortality. This association has been identified in the general population and in those with chronic kidney disease (CKD). The risk of adverse outcomes appears to begin with phosphorus concentrations within the upper limit of the normal reference range. Multiple experimental studies have suggested pathogenetic mechanisms that involve direct and indirect effects of high phosphorus concentrations to explain these associations. Drawing from these observations, guideline-forming agencies have recommended that serum phosphorus concentrations be maintained within the normal reference range in patients with CKD and that dietary phosphorus restriction or use of intestinal phosphate binders should be considered to achieve this goal. However, outside the dialysis population, the links between dietary phosphorus intake and serum phosphorus concentrations, and dietary phosphorus intake and CVD events, are uncertain. With specific reference to the nondialysis populations, this review discusses the available data linking dietary phosphorus intake with serum phosphorus concentrations and CVD events.

  8. Electrochemistry of oxygen ion transport in slag

    鲁雄刚; 丁伟中; 李福燊; 李丽芬; 周国治


    A systematic experiment relating to the electrochemistry of oxygen ion transport in slag has been studied in lab.An equivalent circuit has been used to describe ion transfer between metal and slag in this paper and a kinetic model with electrochemical characteristic representing oxygen ion immigration has been worked out.The different experimental phenomena can be explained generally by this model.It can be seen that the theoretical results are in good agreement with experiments.The comparison of experimental data with model calculation proved that the electrochemical model is right.

  9. Limitation of Sulfide Capacity Concept for Molten Slags

    Jung, In-Ho; Moosavi-Khoonsari, Elmira


    The sulfide capacity concept has been widely used in pyrometallurgy to define sulfur removal capacities of slags. Typically, the sulfide capacity is considered to be a unique slag property depending only on temperature regardless of partial pressures of oxygen and sulfur. In the present study, it is demonstrated that sulfide capacities of slags in particular those of Na2O-containing slags can vary with partial pressures of oxygen and sulfur due to large solubility of sulfide in Na2O-containing slag systems.

  10. 不同人工湿地基质除磷效率研究%Removal Rate of Phosphorus by Different Constructed Wetland Substrates



    [ Objective ] The study aimed to discuss the removal rate of phosphorus by different constructed wetland substrates. [ Method ] Based on a static experiment, we analyzed the removal rate and characteristics of phosphorus by different constructed wetland substrates like steel slag, cinder slag, shale, boiler slag, soil and gravel. [ Result ] The maximum adsorption of phosphorus by various substrates showed as follows: steel slag > cinder slag > shale > boiler slag > soil > gravel. When the initial concentration of phosphorus was 5 mg/L, the removal rate of the six substrate was 99.76%, 85.8%, 71.2%, 63.0%, 46.8% and 11.7% respectively. Shale and boiler slag can be used as a substrate under constructed wetland. Cinder slag could be chosen as a renewable substrate for intensifying phosphorus removal. Steel slag could be used at the end of constructed wetlands to treat TP in outflows. [Conclusion] The research could provide theoretical references for choosing a suitable substrate for constructed wetlands to remove phosphorus in future.%[目的]探讨不同人工湿地基质对磷的去除效率.[方法]通过静态试验,选取钢渣、煤渣、炉渣、页岩、土壤、砂石6种基质,研究不同人工湿地基质对磷的去除效率及除磷特性.[结果]6种基质对磷的去除能力表现为钢渣>煤渣>炉渣>页岩>土壤>砂石;当总磷初始浓度为5mg/L时,6种基质对总磷的去除率分别为99.8%、85.8%、71.2%、63.0%、46.8%、11.7%.页岩和炉渣适合作潜流型人工湿地基质;煤渣适合作为可更换湿地基质,强化除磷效果;钢渣可用于潜流型湿地末端,对尾水TP进行处理.[结论]该研究为今后人工湿地基质的选取提供了理论参考.

  11. Valorization of BOF Steel Slag by Reduction and Phase Modification: Metal Recovery and Slag Valorization

    Liu, Chunwei; Huang, Shuigen; Wollants, Patrick; Blanpain, Bart; Guo, Muxing


    Basic oxygen furnace (BOF) steel slag is a main byproduct in steelmaking, and its valorization is therefore of considerable interest, from a metal-recovery perspective and from a residue-utilization perspective. In the present study, the carbothermic reduction of BOF slag was investigated systematically. The reductions of Fe- and P-containing phases (i.e., oxide and compounds) are discussed. Effects of Al2O3 and SiO2 additions on the solidification microstructure and mineralogy associated with the reduction processes were also investigated. The formation and growth of the extracted metallic phase are discussed, and the mineralogy of the residue slag is determined. We conclude that by controlling the additions under a rapid cooling condition, it is possible to extract metallic iron as high-grade metal and simultaneously to utilize the remaining slag for construction applications.

  12. Impact of electro slag remelting on 14 109 steel properties

    Pribulová A.


    Full Text Available The Electro Slag Remelting (ESR is one of the remelting processes in the field of metal refinery. In this process, the slag plays various roles, such as heat generation, protection of melt, and chemical refining. The main objective of the experiments described in this article was to identify the most appropriate slag composition for the electro slag remelting of the steel in order to achieve the chemical composition compliant with the standard applicable to the given steel, minimum sulphur content, minimum contents of oxide and sulphide inclusions, as well as mechanical properties corresponding to the standard applicable to the steel STN 14 109. Ten electrodes were remelted, whereas the remelting was carried out under 8 slags. The used slags containing 70% of CaF2 and 30% of Al2O3 with different addition of CaO, the slags consisted of the same components as previous slags, whereas the ratio of individual components was 1:1:1, and with SiO2 and MgO and slag without Al2O3. With regard to all the above mentioned facts, the slag types which may be regarded as the most appropriate for the STN 14 109 steel remelting are the basic slags containing 70% of CaF2 - 30% of Al2O3 with added 30 and 45 weight % of CaO.

  13. Research and development of blasting abrasive made of steelmaking slag

    TANG Oujing


    This study focuses on the development of a new type of nonmetallic steelmaking slag abrasive.The performance,processing,and application of steelmaking slag as a nonmetallic abrasive are introduced.The chemical composition,hardness,crushing value,and particle gradation of steelmaking slag are analyzed.A processing method for steelmaking slag as a blasting abrasive is suggested and evaluated.Compared with conventional abrasives such as copper ore sand and cast iron shot,processed steelmaking slag exhibits similar performance and can satisfy abrasive technical requirements.The derusting effect provided by steelmaking slag for a ship deck can reach the Sa2.0 level,and its recyclability is higher than that of copper ore sand.The derusting performance of steelmaking slag is similar to that of copper ore,and it can thus be used in repairing ship decks.

  14. Separation of Iron Droplets From Titania Bearing Slag

    WANG Ming-yu; LOU Tai-ping; ZHANG Li; SUI Zhi-tong


    Owing to smelting vanadium-titanium magnetite ore, the amount of iron entrainment in slag as droplets is far higher than that in conventional BF slag. However, the iron droplets can be easily settled by blowing air into the molten slag. The results show that more than 80% of iron droplets in titania bearing slag can be settled and separated after treatment. The temperature rise of molten slag during the oxidizing process and the decreased viscosity caused by the component change of slag as well as air stirring in slag both accelerate the iron droplets settling. The vanadium content in the settled iron droplets and the original iron droplets was obtained by chemical analysis. The possible reason for the increased vanadium in the settled iron droplets was discussed by thermodynamic principles.

  15. Characteristics and environmental aspects of slag: a review

    Piatak, Nadine M.; Parsons, Michael B.; Seal, Robert R., II


    Slag is a waste product from the pyrometallurgical processing of various ores. Based on over 150 published studies, this paper provides an overview of mineralogical and geochemical characteristics of different types of slag and their environmental consequences, particularly from the release of potentially toxic elements to water. This chapter reviews the characteristics of both ferrous (steel and blast furnace Fe) and non-ferrous (Ag, Cu, Ni, Pb, Sn, Zn) slag. Interest in slag has been increasing steadily as large volumes, on the order of hundreds of millions of tonnes, are produced annually worldwide. Research on slag generally focuses on potential environmental issues related to the weathering of slag dumps or on its utility as a construction material or reprocessing for secondary metal recovery. The chemistry and mineralogy of slag depend on the metallurgical processes that create the material and will influence its fate as waste or as a reusable product.

  16. Yellow nail syndrome

    Dixit Ramakant


    Full Text Available A case of yellow nail syndrome is described in a forty year old male patient who presented with classical triad of this syndrome i.e. deformed yellow nails, lymph-edema and chronic recurrent pleural effusion. The practical problems in the di-agnosis are also briefly discussed with emphasis on awareness of this rare clinical entity.

  17. Mechanisms of phosphate removal from aqueous solution by blast furnace slag and steel furnace slag


    We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate on the slag was rapid and the majority of adsorption was completed in 5~10 min. The adsorption capacity of phosphate by the slag was reduced dramatically by acid treatment. The relative contribution of adsorption to the total removal of phosphate was 26%~28%. Phosphate adsorption on BFS and SFS follows the Freundlich isotherm, with the related constants ofk 6.372 and 1/n 1.739 for BFS, and ofk 1.705 and 1/n 1.718 for SFS. The pH and Ca2+ concentration were decreased with the addition of phosphate, suggesting the formation of calcium phosphate precipitation. At pH 2.93 and 6.93, phosphate was desorbed by about 36%~43% and 9%~11%, respectively.These results indicate that the P adsorption on the slag is not completely reversible and that the bond between the slag particles and adsorbed phosphate is strong. The X-ray diffraction (XRD) patterns of BFS and SFS before and after phosphate adsorption verify SFS is related to the formation of phosphate calcium precipitation and the adsorption on hydroxylated oxides. The results show that BFS and SFS removed phosphate nearly 100%, indicating they are promising adsorbents for the phosphate removal in wastewater treatment and pollution control.

  18. Microstructure characterisation of freeze linings formed in a copper slag cleaning slag

    Jansson J.


    Full Text Available The initial growth rate of freeze linings on water-cooled elements submerged in molten iron silicate slag is fast. The freeze lining microstructure forming on water cooled steel surface in a high-silica, slag cleaning furnace slag of a direct-to-blister copper smelter is mostly glassy or amorphous. It contains 5-30 μm magnetite crystals, very small and larger copper droplets as well as small magnetite and silicate nuclei embedded in the glassy silica-rich matrix. Chemically the formed freeze linings are more silica-rich than the slag from which they were generated. Magnetite (spinel is the primary phase of the solidifying SCF slag but it does not form a continuous network through the freeze lining. Its strength is given by the intergranular silica-rich phase which initially is glassy or microcrystalline. Due to only partial slag reduction in the SCF process, large magnetite crystals are present in the freeze lining and seem to interact physically with copper droplets.

  19. Nieuwe wapens in de slag om groen

    Vreke, J.


    Groen verliest in en rond steden vaak de slag. Burgers vinden groene gebieden belangrijk, ze stimuleren beweging, bevorderen de integratie en maken huizen meer waard. Toch kiezen bestuurders uiteindelijk vaak toch voor ‘rood’ omdat dat geld en prestige oplevert. In deze bijdrage wordt verslag gedaan

  20. Recent advances in understanding physical properties of metallurgical slags

    Min, Dong Joon; Tsukihashi, Fumitaka


    Present-day knowledge of the structure and physical properties of metallurgical slags is summarized to address structure-property and inter-property relationships. Physical properties of slags including viscosity, electrical conductivity, and surface tension is reviewed focusing on the effect of slag structure, which is comprehensively evaluated using FT-IT, Raman, and MAS-NMR spectroscopy. The effect of the slag composition on slag structure and property is reviewed in detail: Compositional effect encompasses traditional concepts of basicity, network-forming behaviors of anions, and secondary impact of network-modifying cations. Secondary objective of this review is elucidating the mutual relationship between physical properties of slags. For instance, the relationship between slag viscosity and electrical conductivity is suggested by Walden's rule and discussed based on the experimental results. Slag foaming index is also introduced as a comprehensive understanding method of physical properties of slags. The dimensional analysis was made to address the effect of viscosity, density, and surface tension on the foaming index of slags.

  1. Synthesis and heavy metal immobilization behaviors of slag based geopolymer.

    Yunsheng, Zhang; Wei, Sun; Qianli, Chen; Lin, Chen


    In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavy metals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reach 98.5% greater when heavy metals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavy metals.

  2. Reduction Kinetics of Electric Arc Furnace Oxidizing Slag by Al-Fe Alloy

    Lee, Jaehong; Oh, Joon Seok; Lee, Joonho


    Effects of temperature and slag basicity on the reduction rate of iron oxide in molten synthetic electric arc furnace oxidizing slag by Al-40 wt.%Fe alloy was investigated. An alloy sample was dropped into molten slag in an MgO crucible. When the initial slag temperature was 1723 K, there was no reduction. However, when the initial slag temperature was 1773 K and the slag basicity was 1.1, the reduction was initiated and the temperature of the slag rapidly increased. When the slag basicity was 1.1, increasing the initial slag temperature from 1773 K to 1823 K increases the reaction rate. As the slag basicity increased from 1.1 to 1.4 at 1773 K, the reaction rate increased. From SEM analysis, it was found that an Al2O3 or a spinel phase at the slag-metal interface inhibited the reaction at a lower temperature and a lower slag basicity.

  3. Leaching of heavy metals from steelmaking slags

    Gomes, J. F. P


    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. Investigation on the Potentials of Cupola Furnace Slag in Concrete

    Stephen Adeyemi Alabi


    Full Text Available The compressive strength of the concrete designed using blast cupola furnace slag and granulated cupola slag as a coarse aggregate and partial replacement for cement was investigated. A series of experimental studies were conducted involve concrete production in two stages. The first stage comprised of normal aggregate concrete (NAC produced with normal aggregates and 100% ordinary Portland cement (OPC. Meanwhile, the second stage involved production of concrete comprising of cupola furnace slag an aggregates with 100% ordinary Portland cement (OPC and subsequently with 2%, 4%, 6%, 8% and 10% cementitious replacement with granulated cupola furnace slag that had been grounded and milled to less than 75 µm diameter. The outcomes of compressive strength test conducted on the slag aggregate concrete (SAC with and without granulated slag cementitious replacement were satisfactory compared to normal aggregate concretes (NAC.

  5. The hydraulic potential of high iron bearing steel slags

    Ionescu, Denisa Virginia

    The incorporation of additives to the clinker or to the raw materials stream is a common practice in cement manufacture. However, steel slag, unlike its ironmaking parent the blast furnace slag, it is not a conventional admixture for cement. Currently most steel slags are slow cooled rendering stable crystalline compounds with minor hydraulic value. Nevertheless, if steel slags would be quenched and granulated, the resulting glassy product might display increased hydration and strength development potential. The use of steel slag in cement could contribute to important savings for both cement and steelmaking industries and provide a solution for the environmental problems linked to CO2 emissions and costs of transport and disposal. The purpose of this research is to explore the thermodynamics and kinetics of steel slag hydration in an effort to produce a cement additive, or a more promising material of near Portland cement composition. An important criteria used in the assessment of slags as potential cements is the presence of a glassy phase. At present, it is not very clear why glass enhances the hydration process. However, it is known that the free energy of formation for glasses is less than for crystals so that glasses are easier to hydrate compared to crystalline materials. In the particular case of steel slag, the glassy phase would have to contain high amounts of iron. Steel slags are known to display iron levels approximately 10 times higher than Portland cement and commonly used blast furnace slags. However, the effect of high Fe2O3 levels on the setting and strengthening of cement paste is not clearly understood due to the fact that most cement additives do not present this characteristic. The present work looks at the progress made in recycling steel slag as cement additive, the complexity of the hydration process in slags, the possibilities of improving the hydration potential of slags at laboratory and industrial level, and the problems that still

  6. Optimization of Blended Mortars Using Steel Slag Sand


    A new kind of mortar made of ground granulated blast-furnace slag (GGBFS), gypsum,clinker and steel slag sand (<4.75 mm) was developed. The ratio of steel slag sand to GGBFS was 1:1 and the amount of gypsum was 4% by weight while the dosage of clinker ranged from 0% to 24%. The optimization formulation of such mortar was studied. The content of steel slag sand should be less than 50% according to the volume stability of blended mortar, and the dosage of clinker is about 10% based on the strength development.Besides strength, the hydration heat, pore structure and micro pattern of blended mortar were also determined.The experimental results show the application of steel slag sand may reduce the dosage of cement clinker and increase the content of industrial waste product such as GGBFS, and the clinker is also a better admixture for blended mortar using steel slag sand.

  7. Improving Beneficiation of Copper and Iron from Copper Slag by Modifying the Molten Copper Slag

    Zhengqi Guo


    Full Text Available In the paper, a new technology was developed to improve the beneficiation of copper and iron components from copper slag, by modifying the molten slag to promote the mineralization of valuable minerals and to induce the growth of mineral grains. Various parameters, including binary basicity, dosage of compound additive, modification temperature, cooling rate and the end point temperature of slow cooling were investigated. Meanwhile, optical microscope, scanning electron microscope and energy dispersive spectrometer (SEM-EDS was employed to determine the mineralogy of the modified and unmodified slag, as well as to reveal the mechanisms of enhancing beneficiation. The results show that under the proper conditions, the copper grade of rougher copper concentrate was increased from 6.43% to 11.04%, iron recovery of magnetic separation was increased significantly from 32.40% to 63.26%, and other evaluation indexes were changed slightly, in comparison with unmodified copper slag. Moreover, matte and magnetite grains in the modified slag aggregated together and grew obviously to the mean size of over 50 μm, resulting in an improvement of beneficiation of copper and iron.

  8. Behavior of slag foaming caused by blowing gas in molten slags

    Wu, K.


    The relationship between the height of foaming slag and blowing gas flow rate has been investigated at different temperature and with additives such as coal, coke, graphite and CaO, in order to understand the foaming phenomenon in most metallurgical processes comprehensively. On the basis of experimental results, the regressed foam behavior equations ({delta}=b(center dot)V{sup m}) were obtained. Those correlation coefficients were in range from 0.995 to 0.999. It means that the foam behavior equation can be used to describe foaming ability of the slag foaming caused by blowing gas quantitatively. The foaming index {sigma} is only a limited case for of the foam behavior equation and can be used only at high temperature and without additives for the foaming phenomenon caused by blowing gas. It was found also that the large carbonaceous particles could decrease the height of foaming slag, however the fine carbonaceous and CaO powder could increase it. The basicity of the slag affects the height of foaming slag. (author)

  9. Electrochemical Method to Accelerate Metal-Slag Reaction


    The electrochemical nature of reaction between melt and slag in a closed system was worked out. Experimental results demonstrated that both the rate and reaction extent increase when the electronic conductor or voltage was applied between melt and slag. The bigger the contact area of the conductor with melts is, the faster the reaction rate is. With the increase of applied voltage which is beneficial for electron's migration between metal and slags, the rate and extent of reaction increase.

  10. Reduction of chromium oxide from slags

    Gutiérrez-Paredes, J.


    Full Text Available Experimental and theoretical work were performed to estimate the effect of slag basicity and amount of reducing agents on the reduction of chromium oxide from the slag which interacted with molten steel at 1,600 °C. The slag system contained CaO, MgO, SiO2, CaF2 and Cr2O3 together with Fe-alloys (Fe-Si and Fe-Si-Mg. The CaF2 and MgO contents in the slags were 10 mass % each; Cr2O3 was 25%. The amount of the ferroalloys ranged from 12.5 to 50 g per 100 g of slag. The (CaO+MgO/SiO2 ratio was held at 1 and 2. The Cr yield was determined using both Fe-alloys as reducing agents. Some estimations were made to determine the theoretical effect of temperature, slag basicity, (CaO+MgO/SiO2, and amount of reducing agents in the slag on the chromium recovery. The FACT (Facility for the Analysis of Chemical Thermodynamics computational package is used to determine the equilibrium between the slag and molten steel.

    En el presente trabajo se realiza un estudio teórico y experimental para determinar el efecto de la basicidad de la escoria y la cantidad de agentes reductores sobre la reducción de óxidos de cromo contenidos en la escoria, la cual está en contacto con acero líquido a 1.600 °C. La escoria se prepara con los reactivos CaO, MgO, SiO2, CaF2 y ferroaleaciones (Fe-Si y Fe-Si-Mg. Los contenidos de CaF2 y MgO en la escoria son de 10 %, cada uno, y el de Cr2O3 es 25 %. La cantidad de la ferroaleación varía de 12,5 a 50 g por cada 100 g de escoria. La relación (CaO+MgO/SiO2 tiene los valores de 1 y 2. Se determina la eficiencia de recuperación de cromo empleando los dos tipos de ferroaleaciones. Se realizaron cálculos para determinar el efecto teórico de la temperatura, la basicidad de la escoria, (CaO+MgO/SiO2, y la cantidad de agentes reductores sobre la reducci

  11. TRW Advanced Slagging Coal Combustor Utility Demonstration


    The TRW Advanced Slagging Coal Combustor Demonstration Project consists of retrofitting Orange and Rockland (O R) Utility Corporation's Lovett Plant Unit No. 3 with four (4) slagging combustors which will allow the gas/ou desip unit to fire 2.5 sulfur coal. The slogging combustor process will provide NO[sub x] and SO[sub x] emissions that meet NSPS and New York State Envirommental Standards. TRW-CBU scope of work includes the engineering, design and supply of the slogging combustors, coal and limestone feed systems and a control system for these components. During this report period, the design activities for all systems progressed to permit the release of specifications and requests for proposals. Award of contracts for long-delivery items and major equipment are being placed to meet the revised program schedule.

  12. Thermochemistry of calcium oxide and calcium hydroxide in fluoride slags

    Chattopadhyay, S.; Mitchell, A.


    Calcium oxide activity in binary CaF2-CaO and ternary CaF2-CaO-Al2O3 and CaF2-CaO-SiO2 slags has been determined by CO2-slag equilibrium experiments at 1400 °C. The carbonate ca-pacity of these slags has also been computed and compared with sulfide capacity data available in the literature. The similarity in trends suggests the possibility of characterizing carbonate capacity as an alternative basicity index for fluoride-base slags. Slag-D2O equilibrium experi-ments are performed at 1400°C with different fluoride-base slags to determine water solubility at two different partial pressures of D2O, employing a new slag sampling technique. A novel isotope tracer detection technique is employed to analyze water in the slags. The water solubility data found show higher values than the previous literature data by an order of magnitude but show a linear relationship with the square root of water vapor partial pressure. The activity of hydroxide computed from the data is shown to be helpful in estimating water solubility in in-dustrial electroslag remelting (ESR) slags.

  13. Chemical, Mineralogical, and Morphological Properties of Steel Slag

    Irem Zeynep Yildirim


    Full Text Available Steel slag is a byproduct of the steelmaking and steel refining processes. This paper provides an overview of the different types of steel slag that are generated from basic-oxygen-furnace (BOF steelmaking, electric-arc-furnace (EAF steelmaking, and ladle-furnace steel refining processes. The mineralogical and morphological properties of BOF and electric-arc-furnace-ladle [EAF(L] slag samples generated from two steel plants in Indiana were determined through X-Ray Diffraction (XRD analyses and Scanning Electron Microscopy (SEM studies. The XRD patterns of both BOF and EAF(L slag samples were very complex, with several overlapping peaks resulting from the many minerals present in these samples. The XRD analyses indicated the presence of free MgO and CaO in both the BOF and EAF(L slag samples. SEM micrographs showed that the majority of the sand-size steel slag particles had subangular to angular shapes. Very rough surface textures with distinct crystal structures were observed on the sand-size particles of BOF and EAF(L slag samples under SEM. The characteristics of the steel slag samples considered in this study are discussed in the context of a detailed review of steel slag properties.

  14. Evaluation of copper slag blast media for railcar maintenance

    Sagers, N. W.; Finlayson, Mack H.


    Copper slag was tested as a blasting substitute for zirconium silicate which is used to remove paint from railroad cars. The copper slag tested is less costly, strips paint faster, is produced near the point of need, provides a good bonding surface for paint, and permits the operator to work in a more comfortable position, i.e., standing nearly erect instead of having to crouch. Outdoor blasting with the tested Blackhawk (20 to 40 mesh) copper slag is also environmentally acceptable to the State of Utah. Results of tests for the surface erosion rate with copper slag blasting are included.

  15. Evaluation of copper slag blast media for railcar maintenance

    Sagers, N. W.; Finlayson, Mack H.


    Copper slag was tested as a blasting substitute for zirconium silicate which is used to remove paint from railroad cars. The copper slag tested is less costly, strips paint faster, is produced near the point of need, provides a good bonding surface for paint, and permits the operator to work in a more comfortable position, i.e., standing nearly erect instead of having to crouch. Outdoor blasting with the tested Blackhawk (20 to 40 mesh) copper slag is also environmentally acceptable to the State of Utah. Results of tests for the surface erosion rate with copper slag blasting are included.

  16. Artificial neural network model to predict slag viscosity over a broad range of temperatures and slag compositions

    Duchesne, Marc A. [Chemical and Biological Engineering Department, University of Ottawa, 161 Louis Pasteur, Ottawa, Ont. (Canada); CanmetENERGY, 1 Haanel Drive, Ottawa, Ontario (Canada); Macchi, Arturo [Chemical and Biological Engineering Department, University of Ottawa, 161 Louis Pasteur, Ottawa, Ont. (Canada); Lu, Dennis Y.; Hughes, Robin W.; McCalden, David; Anthony, Edward J. [CanmetENERGY, 1 Haanel Drive, Ottawa, Ontario (Canada)


    Threshold slag viscosity heuristics are often used for the initial assessment of coal gasification projects. Slag viscosity predictions are also required for advanced combustion and gasification models. Due to unsatisfactory performance of theoretical equations, an artificial neural network model was developed to predict slag viscosity over a broad range of temperatures and slag compositions. This model outperforms other slag viscosity models, resulting in an average error factor of 5.05 which is lower than the best obtained with other available models. Genesee coal ash viscosity predictions were made to investigate the effect of adding Canadian limestone and dolomite. The results indicate that magnesium in the fluxing agent provides a greater viscosity reduction than calcium for the threshold slag tapping temperature range. (author)

  17. Durability of Alkali Activated Blast Furnace Slag

    Ellis, K.; Alharbi, N.; Matheu, P. S.; Varela, B.; Hailstone, R.


    The alkali activation of blast furnace slag has the potential to reduce the environmental impact of cementitious materials and to be applied in geographic zones where weather is a factor that negatively affects performance of materials based on Ordinary Portland Cement. The scientific literature provides many examples of alkali activated slag with high compressive strengths; however research into the durability and resistance to aggressive environments is still necessary for applications in harsh weather conditions. In this study two design mixes of blast furnace slag with mine tailings were activated with a potassium based solution. The design mixes were characterized by scanning electron microscopy, BET analysis and compressive strength testing. Freeze-thaw testing up to 100 freeze-thaw cycles was performed in 10% road salt solution. Our findings included compressive strength of up to 100 MPa after 28 days of curing and 120 MPa after freeze-thaw testing. The relationship between pore size, compressive strength, and compressive strength after freeze-thaw was explored.

  18. Influência de calcário e fósforo no desenvolvimento e produção de variedades de maracujazeiro-amarelo Influence of limestone and phosphorus in development and production of varieties of yellow passion fruit

    Edilson Carvalho Brasil


    used was randomized blocks, in factorial scheme 4x4x2 with 16 treatments and 4 repetitions. The factors studied had been four doses of phosphorus (0, 100, 200 and 300 mg dm-3 of P in the triple superphosphate form (SFT; four levels of saturation for bases (initial = 15%, 40%, 65%80 and 90% and two varieties of passion fruit, (yellow and Embrapa Oriental Amazônia. As corrective agent to soil acidity were used calcium (CaCO3 and magnesium (MgCO3 carbonate. At 50 days after planting, it was evaluated: plant height, stem diameter and dry matter of shoots. The liming and phosphorus application influenced positively the development and the dry mater of passion fruit plants. The greatest dry matter production was obtained with combined application of 160 mg dm-3 of P in soil with the base saturation of 47%, which was associated with concentrations of P and Ca of 143 mg dm-3 and 2,9 cmol c dm-3 in the soil, and contents of 2,6 and 10,8 g kg-1 in the shoot dry matter, respectively. The CPATU variety was superior in terms of average diameter of stem and dry matter production of shoots.

  19. Comparative results of copper flotation from smelter slag and granulated smelter slag

    Milanović, Dragan; Stanujkić, Dragiša; Ignjatović, Miroslav R.


    Smelter slag is obtained in the process of metallurgical converting of copper concentrate in the Smelter Plant in Bor, Serbia. Today, the reserves of this material are evaluated at about more of a year, with the average copper content of 0.6-0.9%. Production of copper concentrate by flotation of smelter slag has started in 2001. Flotation concentrate goes to the Copper Smelter once more for production of copper cathodes and the rough flotation tailings go to the flotation tailing dump. Copper...

  20. Evaluation of the slag regime and desulphurization of steel with synthetic slag containing Cr2O3

    Socha, Ladislav; Bažan, Jiří; Morávka, Jan; Styrnal, Petr; Machovčák, Pavel; Opler, Aleš; Trefil, Antonín


    The paper focuses on an evaluation of the slag regime and steel desulphurisation in a ladle with the help of synthetic slags based on Al2O3 containing various mass amounts of Cr2O3 varying from 0.3 % to 3.0 %. The aim of the plant experiments was to assess the achieved results when using two types of synthetic slag focusing on the course of desulphurisation, an analysis of the achieved chemical composition of the slag and an evaluation of the influence of oxide Cr2O3 on the increase ...

  1. Byproduct aggregate. Copper slag aggregate, ferronickel slag aggregate; Fukusan kotsuzai. Do suragu kotsuzai, fuero nikkeru suragu kotsuzai

    Kajiwara, Toshitaka


    Copper slag aggregate and ferronickel slag aggregate has not only usual substitute of sand or crushed sand but many features unlike sand or unlike crushed sand. It has many features unlike sand or crushed sand. It seems that especially, behavior of the particulates minute is features of deserving in addition, the examination in future. Of course, one feature also consists on the merit on the demerit by the use. And, copper slag aggregate, ferronickel slag aggregate have also limited the production place at the output of about 2 million annual production tons. These features are utilized, and in addition, wants to teach and want to receive the wider usage. (NEDO)

  2. 钢渣处理与综合利用技术%Technologies of steel slag treatment and comprehensive utilization of resouces

    任奇; 王颖杰; 李双林


    结合国内外钢渣处理与利用现状,分析评述了钢渣余热自解热闷工艺、浅盘热泼工艺、风淬工艺、水淬工艺、滚筒处理工艺等钢渣处理工艺,及钢渣作为钢铁冶炼熔剂、用作建筑材料、筑路材料、回收废钢、钢渣微粉等资源综合利用技术。建议在电炉氧化渣水淬工艺、高磷铁水冶炼脱磷处理及钢渣加工设备等方面加强研究和改进。%According to the present situation of steel slag treatment,some technologies of steel slag treatment and comprehensive utilization of resouces are reviewed in this paper.The steel slag treatment technologies include: hot water splash,air quenched,water quenched,roller processing,etc.The technologies of comprehensive utilization of resouces include:using steel slag as smelting flux,building materials,road construction materials,scrap recycling,micro powder,etc.The authors suggest to strengthen the investigation and improvements in the fields of disposal and utilization of water-quenched electric furnace oxidizing slag,dephosphrization treatment equipment and steel slag processing equipment for high phosphorus molten iron smelting.

  3. Distribution Behavior of Vanadium, Chromium and Phosphorous between Basic Slag and Semi-Steel

    Liu, Xuan; Diao, Jiang; Zhang, Tao; Xie, Bing

    In the present study, the oxidation process of vanadium and chromium bearing hot metal was investigated by using CaO-FetO-SiO2 slags at 1653K in MoSi2 furnace. The results indicated that both the vanadium distribution LV and chromium distribution LCr were of the orders of 2.2˜2.4 with the basicity range of 1.32˜1.78 and FeO weight percent range of 28%˜45%. Both LV and LCr decreased with increasing basicity and decreasing FeO weight percent. The phosphorus distribution LP was of the order of 1.34˜1.56. However, LP increased with increasing basicity and decreasing FeO weight percent. The oxidation ratio values of V and Cr in hot metal were above 84% and the values of P were nearly 50%. In other words, it means the addition of CaO in vanadium slag provided a certain ability of dephosphorization along with keeping high oxidation ratios of V and Cr.

  4. China Customs Removed the Import Tax on Titanium Slag


    <正>The long waited solution to the problem relating to the import of titanium slag has finally resolved. According to China Customs report, the import of titanium slag no longer requires tax payment as from January 1, 2007. This decision will help with the healthy development of China’s titanium industry and increase China’s competitiveness in the international marketplace.

  5. Sulfide capacity of high alumina blast furnace slags

    Shankar, Amitabh; Görnerup, Märten; Seetharaman, S.; Lahiri, A. K.


    Sulfide capacities of high alumina blast furnace slags were experimentally determined using the gas-slag equilibration technique. Two different slag systems were considered for the current study, namely, CaO-SiO2-MgO-Al2O3 quaternary and CaO-SiO2-MgO-Al2O3-TiO2 quinary system. The liquid slag was equilibrated with the Ar-CO-CO2-SO2 gas mixture. Experiments were conducted in the temperature range of 1773 to 1873 K. The effects of temperature, basicity, and the MgO and TiO2 contents of slags on sulfide capacity were studied. As expected, sulfide capacity was found to increase with the increase in temperature and basicity. At the higher experimental temperature, titania decreases the sulfide capacity of slag. However, at the lower temperature, there was no significant effect of titania on the sulfide capacity of slag. Sulfide capacity increases with the increase in MgO content of slag if the MgO content is more than 5 pct.

  6. Crystallization of Synthetic Blast Furnace Slags Pertaining to Heat Recovery

    Esfahani, Shaghayegh

    Heat recovery from blast furnace slags is often contradicted by another requirement, to generate amorphous slag for its use in cement production. As both the rate and extent of heat recovery and slag structure are determined by its cooling rate, a relation between the crystallization kinetics and the cooling conditions is highly desired. In this study, CaO-SiO2-Al2O3-MgO (CSAM) slags with different basicities were studied by Single Hot Thermocouple Technique (SHTT) during isothermal treatment and non-isothermal cooling. Their time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams were plotted and compared with each other. Furthermore, kinetic parameters such as the Avrami exponent (n), rate coefficient (K) and effective activation energy of crystallization (EA) were found by analysis of data obtained from in-situ observation of glassy to crystalline transformation and image analysis. Also, the dependence of nucleation and growth rates of crystalline phases were quantified as a function of time, temperature, and slag basicity. Together with the observations of crystallization front, they facilitated establishing the dominant mechanisms of crystallization. In addition to the experimental work, a mathematical model was developed and validated that predicts the amount of crystallization during cooling. A second mathematical model that calculates temperature history of slag during its cooling was coupled with the above model, to allow studying the effect of parameters such as the slag/air ratio and granule size on the heat recovery and glass content of slag.

  7. Refractory Degradation by Slag Attack in Coal Gasification


    REFRACTORY DEGRADATION BY SLAG ATTACK IN COAL GASIFICATION Jinichiro Nakano 1,2 , Sridhar Seetharaman 1,2 , James Bennett 3 , Kyei-Sing...00-2009 4. TITLE AND SUBTITLE Refractory Degradation by Slag Attack in Coal Gasification 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  8. Treatment of LF slag to prevent powdering during cooling

    Ghorai S.


    Full Text Available The polymorphic transformation of the monoclinic β-polymorph to the orthorhombic γ-polymorph of di-calcium silicate at around 500°C during cooling results in disintegration of slag. The slag generated, during the production of thermo mechanically treated steel in ladle furnace at M/s Tata Steel Limited, Jamshedpur, India, behaves in similar manner. An attempt has been made to prevent the crumbling of ladle furnace slag. The experiments were conducted in 10 kg air induction furnace. Various types of silica source were used to prevent the disintegration of ladle furnace slag by reducing the basicity and optimizing the additives amount. Apart from silica sources, other additives like borax and barium carbonate were also used to stabilize the β phase. Present investigation reveals that disintegration of ladle furnace slag can be prevented either by addition of 0.2% boarx or 2% barium carbonate. Dust formation can also be prevented by decreasing the ladle furnace slag basicity to about 1.7. Toxicity Characteristic Leaching Procedure test, of the borax and barium carbonate treated slag samples, indicates that barium carbonate treated slag cannot be used for the dusting prevention as it contains high level of barium.

  9. Study of Reaction Between Slag and Carbonaceous Materials

    Maroufi, Samane; Mayyas, Mohannad; Mansuri, Irshad; O'Kane, Paul; Skidmore, Catherine; Jin, Zheshi; Fontana, Andrea; Sahajwalla, Veena


    The chemical interaction of a typical slag of EAF with three different carbon sources, coke, rubber-derived carbon (RDC), coke-RDC blend, was studied in atmospheric pressure at 1823 K (1550 °C). Using an IR-gas analyzer, off-gases evolved from the sample were monitored. While the coke-RDC blend exhibited the best reducing performance in reaction with molten slag, the RDC sample showed poor interaction with the molten slag. The gasification of the coke, RDC, and coke-RDC blend was also carried out under oxidizing conditions using a gas mixture of CO2 (4 wt pct) and Ar (96 wt pct) and it was shown that the RDC sample had the highest rate of gasification step C0 \\mathop{\\longrightarrow}\\limits{{k3 }}{CO} + nCf (11.6 site/g s (×6.023 × 1023/2.24 × 104)). This may be attributed to its disordered structure confirmed by Raman spectra and its nano-particle morphology observed by FE-SEM. The high reactivity of RDC with CO2 provided evidence that the Boudouard reaction was fast during the interaction with molten slag. However, low reduction rate of iron oxide from slag with RDC can be attributed to the initial weak contact between RDC and molten slag implying that the contact between carbonaceous matter and slag plays significant roles in the reduction of iron oxide from slag.

  10. Micronutrient availability from steel slag amendment in pine bark substrates

    Steel slag is a byproduct of the steel industry that can be used as a liming agent, but also has a high mineral nutrient content. While micronutrients are present in steel slag, it is not known if the mineral form of the micronutrients would render them available for plant uptake. The objective of...

  11. Phase analytical studies of industrial copper smelting slags. Part I: Silicate slags

    Rüffler, R.; Dávalos, J.


    The pyrometallurgical extraction of copper from sulfide ore concentrates is determined by the behaviour of the associated iron during smelting. Hence, 57Fe Mössbauer spectroscopy is an attractive tool for studying the phases in silicate slags from German and Chilean smelting plants. Other methods used were ore microscopy, electron microprobe analysis, and X-ray powder diffraction.

  12. Slag-Resistance of MgAlON Spinel


    The slag-resistance and microstructural changes after the slag tests of MgAlON spinel containing different amount of nitrogen were studied by means of crucible slag-resistant experiment, SEM and EDS in the work. The results show that the slag-resistance of MgAlON is dependent on the nitrogen content, and the optimum amount is 2.88%. The structure is not changed although the grains have been permeated by some silicon, calcium and iron. A glass phase which contained nitrogen formed in the metamorphic layer. The glass can improve the ability of the slag-resistance of MgAlON because of its higher viscosity.

  13. Chemical and mineralogical characterizations of a copper converter slag


    A copper converter slag was examined chemically and mineralogically to determine its existing phases, in particular those containing Co and Cu. The slag consists predominantly of fayalite and magnetite, together with some glass,chalcocite, and metallic copper. Copper is entrapped in the slag mostly as chalcocite and metallic copper, as well as trace copper oxide. There was no indication of any independent Co mineral in the slag, but Co was found to be enriched in fayalite and megnetite as solid solution, although Co was detected in all the phases of the slag by SEM-EDX (scanning electron microscopy equipped with model EDAX-9100 energy dispersive spectrometer) and WDS (model WDX-2A X-ray wave-length dispersive spectrometer).

  14. Characterization and Recovery of Valuables from Waste Copper Smelting Slag

    Prince, Sarfo; Young, Jamie; Ma, Guojun; Young, Courtney

    Silicate slags produced from smelting copper concentrates contains valuables such as Cu and Fe as well as heavy metals such as Pb and As which are considered hazardous. In this paper, various slags were characterized with several techniques: SEM-MLA, XRD, TG-DTA and ICP-MS. A recovery process was developed to separate the valuables from the silicates thereby producing value-added products and simultaneously reducing environmental concerns. Results show that the major phases in air-cooled slag are fayalite and magnetite whereas the water-cooled slag is amorphous. Thermodynamic calculations and carbothermal reduction experiments indicate that most of Cu and Fe can be recovered from both types using minor amounts of lime and alumina and treating at 1350°C (1623K) or higher for 30 min. The secondary slag can be recycled to the glass and/or ceramic industries.

  15. Roles of Mineralogical Phases in Aqueous Carbonation of Steelmaking Slag

    Huining Zhang


    Full Text Available Mineralogical phases of steelmaking slags have significant influences on the carbonation of the slags. In this paper, the effects of temperature and reaction time on the conversion of calcium-related phases and the carbonation degree of a slag sample were studied. The experimental conditions were a liquid-to-solid ratio of 20 mL/g, a carbon dioxide flow rate of 1 L/min and a slag particle size of 38–75 μm. The results show that the optimum carbonation temperature and reaction time are 60 °C and 90 min, respectively, and calcite phase content is about 26.78% while the conversion rates of Ca3Al2O6, CaSiO3, Ca2SiO4 and free CaO are about 40%, 42.46%, 51% and 100%, respectively, and the carbon dioxide sequestration efficiency is about 170 g/kg slag.

  16. Modeling and control of copper loss in smelting slag

    Tan, Pengfu


    A series of technical improvements have been implemented to address the issue of high copper losses in rotary holding furnace (RHF) slag, which were experienced at the Xstrata Copper Smelter at Mount Isa in 2007 and 2008. The copper losses in smelting slag in the RHF were more than 3% in 2006 and 2007. Thermodynamic models and viscosity models have been applied in the operation of Xstrata Copper Smelter in Australia. The theory of RHF key performance indicators has also been developed to reduce the copper losses in RHF slag. The RHF KPIs Theory has been applied in Mount Isa Copper Smelter. The copper losses in RHF slag dropped from 3.1% in 2007 to 0.76% in April 2009. The average copper loss in RHF slag in 2009 and 2010 was about 0.9%.

  17. Phosphorus sorption-desorption and effects of temperature, pH and salinity on phosphorus sorption in marsh soils from coastal wetlands with different flooding conditions.

    Bai, Junhong; Ye, Xiaofei; Jia, Jia; Zhang, Guangliang; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui


    Wetland soils act as a sink or source of phosphorus (P) to the overlaying water due to phosphorus sorption-desorption processes. Litter information is available on sorption and desorption behaviors of phosphorus in coastal wetlands with different flooding conditions. Laboratory experiments were conducted to investigate phosphorus sorption-desorption processes, fractions of adsorbed phosphorus, and the effects of salinity, pH and temperature on phosphorus sorption on soils in tidal-flooding wetlands (TW), freshwater-flooding wetlands (FW) and seasonal-flooding wetlands (SW) in the Yellow River Delta. Our results showed that the freshly adsorbed phosphorus dominantly exists in Occluded-P and Fe/AlP and their percentages increased with increasing phosphorus adsorbed. Phosphorus sorption isotherms could be better described by the modified Langmuir model than by the modified Freundlich model. A binomial equation could be properly used to describe the effects of salinity, pH, and temperature on phosphorus sorption. Phosphorus sorption generally increased with increasing salinity, pH, and temperature at lower ranges, while decreased in excess of some threshold values. The maximum phosphorus sorption capacity (Qmax) was larger for FW soils (256 mg/kg) compared with TW (218 mg/kg) and SW soils (235 mg/kg) (p < 0.05). The percentage of phosphorus desorption (Pdes) in the FW soils (7.5-63.5%) was much lower than those in TW (27.7-124.9%) and SW soils (19.2-108.5%). The initial soil organic matter, pH and the exchangeable Al, Fe and Cd contents were important factors influencing P sorption and desorption. The findings of this study indicate that freshwater restoration can contribute to controlling the eutrophication status of water bodies through increasing P sorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Glacial atmospheric phosphorus deposition

    Kjær, Helle Astrid; Dallmayr, Remi; Gabrieli, Jacopo; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Svensson, Anders; Vallelonga, Paul


    Phosphorus in the atmosphere is poorly studied and thus not much is known about atmospheric phosphorus and phosphate transport and deposition changes over time, though it is well known that phosphorus can be a source of long-range nutrient transport, e.g. Saharan dust transported to the tropical forests of Brazil. In glacial times it has been speculated that transport of phosphorus from exposed shelves would increase the ocean productivity by wash out. However whether the exposed shelf would also increase the atmospheric load to more remote places has not been investigated. Polar ice cores offer a unique opportunity to study the atmospheric transport of aerosols on various timescales, from glacial-interglacial periods to recent anthropogenic influences. We have for the first time determined the atmospheric transport of phosphorus to the Arctic by means of ice core analysis. Both total and dissolved reactive phosphorus were measured to investigate current and past atmospheric transport of phosphorus to the Arctic. Results show that glacial cold stadials had increased atmospheric total phosphorus mass loads of 70 times higher than in the past century, while DRP was only increased by a factor of 14. In the recent period we find evidence of a phosphorus increase over the past 50 yrs in ice cores close to human occupation likely correlated to forest fires. References: Kjær, Helle Astrid, et al. "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores." Environmental science & technology 47.21 (2013): 12325-12332. Kjær, Helle Astrid, et al. "Greenland ice cores constrain glacial atmospheric fluxes of phosphorus." Journal of Geophysical Research: Atmospheres120.20 (2015).

  19. Eat Healthy, Eat Yellow

    Cindy Gu


    What comes to mind when you think of yellow? Sunflowers, the school bus or the smiley face? As a food-junkie and a health nut, when I hear the word yellow, savory soy beans, munchy bananas and sweet corn are things that pop into my mind. That's how much I love food. Hopeless? Perhaps.

  20. Cucumber vein yellowing virus

    Cucurbits are an important crop of temperate, subtropical and tropical regions of the world. Cucumber vein yellowing virus (CVYV) is a major viral pathogen of cucurbits. This chapter provides an overview of the biology of CVYV and the disease it causes....

  1. Squash vein yellowing virus

    Cucurbits are an important crop of temperate, subtropical and tropical regions of the world. Squash vein yellowing virus (SqVYV) is a major viral pathogen of cucurbits. This chapter provides an overview of the biology of SqVYV and the disease it causes....

  2. The yellow Light Offensive


    Arevised traffic regulation, seen as the harshest ever by many, took effect on January 1. Accordingly, drivers who run yellow lights will have six points deducted from the 12 allocated on their licenses. Those who have any part of their vehicles crossing the line at the time of change will not be punished.

  3. Asian Yellow Goat Cloned


    @@ It was released on August 24,2005 by Prof. CHEN Dayuan (Da-Yuan Chen) from the CAS Institute of Zoology that the first success in cloning the Asian Yellow Goat by nuclear transfer had recently been achieved in east China's Shandong Province.

  4. 黄河口滨岸潮滩不同生境下翅碱蓬生物量空间分形特征与磷营养动态%Biomass spatial fractal characteristics and phosphorus nutrient dynamics of Suaeda salsa under different growth conditions of the intertidal zone in the Yellow River estuary

    牟晓杰; 孙志高; 刘兴土


    2008年5-11月,对黄河口滨岸潮滩不同生境下翅碱蓬的生物量空间分形特征及磷(P)营养动态进行了研究.结果表明,中潮滩翅碱蓬(JP1)和低潮滩翅碱蓬(JP2)地上生物量与株高的对数值线性相关(P<0.01),分形维数(D)分别为1.692~3.839和2.260~3.955,二者地上生物量的动态积累具有自相似性,分别遵从D=2.012和D=2.366幂函数增长的分形生长过程;JP1,JP2根、茎的全磷(TP)含量变化较为一致,整体呈递减趋势,而叶的TP含量波动变化明显且差异较大.二者不同器官的P累积量和累积速率季节变化明显,前者不同器官的P累积量一般明显高于后者;JP1、JP2不同器官的P分配比在各时期差异较大,但整体以叶的分配比占优,茎次之,根最低;JP1、JP2不同器官N/P变化具有明显的时间性,前者为9.87± 3.47<14,其生长受N限制,而后者为15.73±5.00<16,其生长同时受N、P限制,但更多受P限制.研究发现,JP1、JP2生物量、TP含量、累积量、累积速率、分配比和养分限制状况的差异主要与其生态学特性和所处生境的水盐状况有关.%From May to November 2008, biomass spatial fractal characteristics and phosphorus nutrient dynamics of Suaeda salsa under different growth conditions in the intertidal zone of the Yellow River estuary were studied. The logarithm values of aboveground biomass and plant height of S. salsa in middle (JP1) and low tidal flat (JP2) were linearly correlated, and the ranges of fractal dimensions (D) were 1. 692 - 3. 839 and 2. 260 - 3. 955, respectively. The dynamic accumulation of aboveground biomass of JP1 and JP2 had self-similarity, being a fractal growth process which fitted the increase rule of power function: D was 2. 012 and 2. 366, respectively. The changes of total phosphorus (TP) content in roots and stems of JP1 and JP2 were consistent, generally decreasing in the growing season, while TP content in leaves fluctuated greatly. The amount of

  5. Catalysts derived from waste slag for transesterification

    Xiaowei Zhang; Wei Huang


    MgO-CaO/SiO2 solid catalysts derived from waste slag (WS) of metal magnesium plant were prepared.The catalytic performances were evaluated in the transesterification of rapeseed oil with methanol to biodiesel in a 500 mL three-necked reactor under atmospheric pressure.The basic strengh of the catalyst reached 22.0 measured by indicators accroding to Hammett scale.The results show that the MgO-CaO/SiO2 is an excellent catalyst for transesterification, and the conversion of rapeseed oil reach 98% under the optimum condition.

  6. Phosphorus recovery from wastes

    Phosphorus (P) is an important macro-nutrient essential for all living organisms and phosphate rock is the main raw material for all inorganic P fertilizers. It is expected that there will be a P peak and resulting P fertilizer shortage in near future. In general, phosphorus use efficiency is low a...

  7. On the Dissolution Behavior of Sulfur in Ternary Silicate Slags

    Kang, Youn-Bae; Park, Joo Hyun


    Sulfur dissolution behavior, in terms of sulfide capacity ( C S), in ternary silicate slags (molten oxide slags composed of MO - NO - SiO2, where M and N are Ca, Mn, Fe, and Mg), is discussed based on available experimental data. Composition dependence of the sulfur dissolution, at least in the dilute region of sulfur, may be explained by taking into account the cation-anion first-nearest-neighbor (FNN) interaction (stability of sulfide) and the cation-cation second-nearest-neighbor (SNN) interaction over O anion (oxygen proportions in silicate slags). When the Gibbs energy of a reciprocal reaction MO + NS = MS + NO is positive, the sulfide capacity of slags with virtually no SiO2 or low SiO2 concentration decreases as the concentration of MO increases. However, in some slags, as SiO2 concentration increases, replacing NO by MO at a constant SiO2 concentration may increase sulfide capacity when the basicity of NO is less than that of MO. This phenomenon is observed as rotation of iso- C S lines in ternary silicate slags, and it is explained by simultaneous consideration of the stability of sulfide and oxygen proportions in the silicate slags. It is suggested that a solution model for the prediction of sulfide capacity should be based on the actual dissolution mechanism of sulfur rather than on the simple empirical correlation.

  8. Characterization and recovery of copper values from discarded slag.

    Das, Bisweswar; Mishra, Barada Kanta; Angadi, Shivakumar; Pradhan, Siddharth Kumar; Prakash, Sandur; Mohanty, Jayakrushna


    In any copper smelter large quantities of copper slag are discarded as waste material causing space and environmental problems. This discarded slag contains important amounts of metallic values such as copper and iron. The recovery of copper values from an Indian smelter slag that contains 1.53% Cu, 39.8% Fe and 34.65% SiO(2) was the focus of the present study. A complete investigation of the different phases present in the slag has been carried out by means of optical microscopy, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. It is observed that iron and silica are mostly associated with the fayalite phase whereas copper is present in both oxide and sulfide phases. These oxide and sulfide phases of copper are mostly present within the slag phase and to some extent the slag is also embedded inside the oxide and sulfide phases. The recovery of copper values from the discarded slag has been explored by applying a flotation technique using conventional sodium isopropyl xanthate (SIX) as the collector. The effects of flotation parameters such as pH and collector concentration are investigated. Under optimum flotation conditions, it is possible to achieve 21% Cu with more than 80% recovery.

  9. Vanadium bioavailability in soils amended with blast furnace slag

    Larsson, Maja A., E-mail: [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Baken, Stijn, E-mail: [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Smolders, Erik, E-mail: [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Cubadda, Francesco, E-mail: [Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161 (Italy); Gustafsson, Jon Petter, E-mail: [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Brinellvägen 28, 100 44 Stockholm (Sweden)


    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg{sup −1}) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

  10. Characterization of chilean copper slag smelting nineteenth century

    Amin Nazer


    Full Text Available The aim of this work is to characterize four copper smelters slag nineteenth century, from abandoned landfills in Atacama Region - Chile, using the techniques of X-ray fluorescence (XRF, X-ray diffraction (XRD, scanning electron microscopy (SEM, particle analysis by laser diffraction (ADL, Fourier Transform Infrared Spectroscopy (FTIR and thermogravimetric analysis (TGA. Copper slags studied were chemically classified as acidic slags, this slags presented higher SiO2 content (38–49% than Fe2O3 (18–37% and a significant amount of CaO (8–26% and Al2O3 (8.5%. Mineralogy and structure was varied, presenting one of them an amorphous structure and the remaining three, a crystalline structure with partially amorphous character. The majority mineral phases presented in the copper slag were diopside, fayalite, magnetite, cristobalite and clinoferrosilita. Calcium levels indicate that the slags could have cementitious properties for use as a binder in construction materials. Moreover, the significant amount of slag available and CuO content (0.6–1.2% show that may be of interest as raw material for metal recovery.

  11. Vanadium bioavailability in soils amended with blast furnace slag.

    Larsson, Maja A; Baken, Stijn; Smolders, Erik; Cubadda, Francesco; Gustafsson, Jon Petter


    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg(-1)) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

  12. Utilizing steel slag in environmental application - An overview

    Lim, J. W.; Chew, L. H.; Choong, T. S. Y.; Tezara, C.; Yazdi, M. H.


    Steel slags are generated as waste material or byproduct every day from steel making industries.The potential environmental issues which are related with the slag dump or reprocessing for metal recovery are generally being focused in the research. However the chemistry and mineralogy of slag depends on metallurgical process which is able to determine whether the steel slag can be the reusable products or not. Nowadays, steel slag are well characterized by using several methods, such as X-ray Diffraction, ICP-OES, leaching test and many more. About the industrial application, it is mainly reused as aggregate for road construction, as armour stones for hydraulic engineering constructions and as fertilizers for agricultural purposes. To ensure the quality of steel slag for the end usage, several test methods are developed for evaluating the technical properties of steel slag, especially volume stability and environmental behaviour. In order to determine its environmental behaviour, leaching tests have been developed. The focus of this paper however is on those applications that directly affect environmental issues including remediation, and mitigation of activities that negatively impact the environment.


    Vas Choudhry; Stephen Kwan; Steven R. Hadley


    The objective of the project entitled ''Utilization of Lightweight Materials Made from Coal Gasification Slags'' was to demonstrate the technical and economic viability of manufacturing low-unit-weight products from coal gasification slags which can be used as substitutes for conventional lightweight and ultra-lightweight aggregates. In Phase I, the technology developed by Praxis to produce lightweight aggregates from slag (termed SLA) was applied to produce a large batch (10 tons) of expanded slag using pilot direct-fired rotary kilns and a fluidized bed calciner. The expanded products were characterized using basic characterization and application-oriented tests. Phase II involved the demonstration and evaluation of the use of expanded slag aggregates to produce a number of end-use applications including lightweight roof tiles, lightweight precast products (e.g., masonry blocks), structural concrete, insulating concrete, loose fill insulation, and as a substitute for expanded perlite and vermiculite in horticultural applications. Prototypes of these end-use applications were made and tested with the assistance of commercial manufacturers. Finally, the economics of expanded slag production was determined and compared with the alternative of slag disposal. Production of value-added products from SLA has a significant potential to enhance the overall gasification process economics, especially when the avoided costs of disposal are considered.

  14. Boron removal from molten silicon using sodium-based slags

    Yin Changhao; Hu Bingfeng; Huang Xinming


    Slag refining,as an important option for boron removal to produce solar grade silicon (SOG-Si) from metallurgical grade silicon (MG-Si),has attracted increasing attention.In this paper,Na2CO3-SiO2 systems were chosen as the sodium-based refining slag materials for boron removal from molten silicon.Furthermore,the effect of Al2O3 addition for boron removal was studied in detail,which showed that an appropriate amount of Al2O3 can help retention of the basicity of the slags,hence improving the boron removal rate.

  15. Study on Apparent Viscosity and Structure of Foaming Slag

    Martinsson, Johan; Glaser, Björn; Sichen, Du


    Foaming slag was generated using induction heating. The foam was found non-Newtonian having much higher apparent viscosity compared to the dynamic viscosity of pure slag. Quenched foam was examined. The appearance of the foaming slag was very different from silicone oil-gas foam. The size of gas bubbles ranged from 0.1 to 4 mm (while in the case of silicone oil, 1 to 2 mm). The gas fraction in the foam was considerably lower than in the case of silicone oil.

  16. Optimizing of Work Arc Furnace to Decopperisation of Flash Slag

    Bydałek A.W.


    Full Text Available Discusses an attempt to optimize the operation of an electric furnace slag to be decopperisation suspension of the internal recycling process for the production of copper. The paper presents a new method to recover copper from metallurgical slags in arc-resistance electric furnace. It involves the use of alternating current for a first period reduction, constant or pulsed DC in the final stage of processing. Even distribution of the electric field density in the final phase of melting caused to achieve an extremely low content of metallic copper in the slag phase. They achieved by including the economic effects by reducing the time reduction.

  17. An approach for phosphate removal with quartz sand, ceramsite, blast furnace slag and steel slag as seed crystal.

    Qiu, Liping; Wang, Guangwei; Zhang, Shoubin; Yang, Zhongxi; Li, Yanbo


    The phosphate removal abilities and crystallization performance of quartz sand, ceramsite, blast furnace slag and steel slag were investigated. The residual phosphate concentrations in the reaction solutions were not changed by addition of the ceramsite, quartz sand and blast furnace slag. The steel slag could provide alkalinity and Ca(2+) to the reaction solution due to its hydration activity, and performed a better phosphate removal performance than the other three. Under the conditions of Ca/P 2.0, pH 8.5 and 10 mg P/L, the phosphate crystallization occurred during 12 h. The quartz sand and ceramsite did not improve the phosphate crystallization, but steel slag was an effective seed crystal. The phosphate concentration decreased drastically after 12 h after addition of steel slag, and near complete removal was achieved after 48 h. The XRD analysis showed that the main crystallization products were hydroxyapatite (HAP) and the crystallinity increased with the reaction time. Phosphate was successfully recovered from low phosphate concentration wastewater using steel slag as seed material.

  18. Removal of P4, PH3 and H2S from Yellow Phosphoric Tail Gas by a Catalytic Oxidation Process

    NingPing; Hans-JoergBart; MaLiping; WangXueqian


    Yellow phosphorus tail gas is a resource used to produce bulk chemicals, such as formates, oxalates, and methanol after its pretreatment and purification. In this study, catalytic oxidation of phosphorus and hydrogen sulfide in yellow phosphorus tail gas was investigated on an ordinary activated carbon (OAC) and a home-made catalyst KU2. The adsorption characteristics of phosphorus and hydrogen sulfide on the catalysts were studied in a fixed-bed system at different temperatures between 20℃ and 140℃ at atmospheric pressure. Both KU2 and OAC are proved to be effective catalysts in the catalytic oxidation process (COP) for H2S and PH3 removal. Purification efficiency increased with the increase of temperature and oxygen concentration in yellow phosphorus tail gases. Under optimized operation conditions, the product gases with a content of hydrogen sulfide <5mg/m3 and total phosphorus <5mg/m3 were obtained by using the COP process. Deactivated catalysts could be restored to the original activated state, even after several regenerations. A mathematical model was developed to simulate the experimental results and the mass transport coefficient from the experiment was evaluated. Good agreement between the experimental breakthrough curves and the model predictions was observed.

  19. Yellow Fever Vaccine: What You Need to Know

    ... www. immunize. org/ vis 1 What is yellow fever? Yellow fever is a serious disease caused by the ... serious cases) 2 How can I prevent yellow fever? Yellow fever vaccine Yellow fever vaccine can prevent yellow ...

  20. Biogeochemistry: Early phosphorus redigested

    Poulton, Simon W.


    Atmospheric oxygen was maintained at low levels throughout huge swathes of Earth's early history. Estimates of phosphorus availability through time suggest that scavenging from anoxic, iron-rich oceans stabilized this low-oxygen world.

  1. Characteristic of wet method of phosphorus recovery from polish sewage sludge ash with nitric acid

    Gorazda Katarzyna


    Full Text Available Sewage Sludge Ash (SSA is a concentrated source of phosphorus and can be successfully recycled via a number of different routes. This paper presents research results on phosphorus recovery from differently combusted sewage sludge with the use of nitric acid extraction. Different SSA forms from Polish thermal utilization stations were compared. It was revealed that sewage treatment technology as well as combustion technology influence many physical and chemical parameters of ashes that are crucial for further phosphorus recovery from such waste according to the proposed method. Presented research defines extraction efficiency, characterized extracts composition and verifies the possibility of using SSA as cheaper and alternative sources of phosphorus compounds. Gdynia, Kielce and Kraków SSA have the best properties for the proposed technology of phosphorus recovery with high extraction efficiency greater than 86%. Unsuitable results were obtained for Bydgoszcz, Szczecin Slag and Warszawa SSA. Extraction process for Łódź and Szczecin Dust SSA need to be improved for a higher phosphorus extraction efficiency greater than 80%.

  2. The behavior of sulfur in industrial pyrometallurgical slags

    Nagamori, Meguru


    Dissolution of sulfur in industrial slags, even at such a low level as 1 mass% S or so, increases the solubility of certain valuable metals by an order of magnitude. The phenomenon is accounted for in terms of Flood-Førland-Grjotheim's model for dianionic salt solutions, whereas its rigorous analysis requires the digaseous Gibbs-Duhem integration. In the research described here, the distribution of sulfur among gas, slag, and metallic iron phases in the bath smelting of iron ore was computer-simulated based on a two-sites model coupled with sulfide capacity data. The solubilities of Ag, Cu, Co, and Ni in industrial slags are reviewed by applying the sulfidic-oxidic dissolution model to copper-matte smelting, nickel-slag cleaning (Falconbridge, Canada), and the imperial smelting process for zinc and lead (Hachinohe, Japan).

  3. Removal of phosphate from aqueous solution with blast furnace slag.

    Oguz, Ensar


    Blast furnace slag was used to remove phosphate from aqueous solutions. The influence of pH, temperature, agitation rate, and blast furnace slag dosage on phosphate removal was investigated by conducting a series of batch adsorption experiments. In addition, the yield and mechanisms of phosphate removal were explained on the basis of the results of X-ray spectroscopy, measurements of zeta potential of particles, specific surface area, and images of scanning electron microscopy (SEM) of the particles before and after adsorption. The specific surface area of the blast furnace slag was 0.4m(2)g(-1). The removal of phosphate predominantly has taken place by a precipitation mechanism and weak physical interactions between the surface of adsorbent and the metallic salts of phosphate. In this study, phosphate removal in excess of 99% was obtained, and it was concluded that blast furnace slag is an efficient adsorbent for the removal of phosphate from solution.

  4. Reduction and foaming of FeO containing slag

    Galgali, R.K.; Datta, P.; Ray, A.K.; Prasad, K.K.; Ray, H.S. [Regional Research Lab., Orissa (India)


    Smelting reduction processes being developed for producing liquid iron using coal and oxygen are attractive because they allow the use of ore fines directly and do not depend on coke. This paper presents a brief review of some aspects of smelting reduction and some results of an experimental investigation carried out on the reduction of 5-20 wt-% FeO in a synthetically prepared slag by various reductants in a plasma reactor. Some results of a simulation of the smelting reduction process by carrying out post-combustion with oxygen lancing over the slag surface are also presented. It has been possible to achieve a steady state condition, namely, 1-2 wt-% FeO in the slag with a slag height of 4-5 cm during periodic addition of a charge consisting of iron ore, coal, and flux. A kinetic analysis of FeO reduction with various reductants is presented in detail.

  5. Vaporization Studies from Slag Surfaces Using a Thin Film Technique

    Seetharaman, Seshadri; Shyrokykh, Tetiana; Schröder, Christina; Scheller, Piotr R.


    The investigations of vanadium vaporization from CaO-SiO2-FeO-V2O5 thin film slags were conducted using the single hot thermocouple technique (SHTT) with air as the oxidizing atmosphere. The slag samples were analyzed after the experiments by SEM/EDX. The vanadium content was found to decrease as a function of time. The loss of vanadium from the slag film after 30 minutes of oxidation was approximately 18 pct and after 50 minutes, it was nearly 56 pct. The possible mechanism of vanadium loss would be the surface oxidation of vanadium oxide in the slag, VO x to V5+, followed by surface evaporation of V2O5, which has a high vapor pressure at the experimental temperature.

  6. Properties of Industrial Slag as Fine Aggregate in Concrete

    A. Ananthi


    Full Text Available The main objective of this paper is to use the industrial waste such as bottom ash and Weld Slag (WS as the partial replacement for fine aggregates in concrete. This paper presents the chemical analysis and strength properties of industrial solid waste such as bottom ash, weld slag 1 (WS 1 and weld slag 2 (WS 2. Their chemical compositions were identified by X-ray powder diffraction (XRD analysis. The qualitative and quantitative elemental analysis of the bottom ash and weld slag was recognized by energy dispersive X-ray analysis and their morphology were studied by Scanning Electron Microscope (SEM. The compressive strength of concrete with 10% replacement of fine aggregate to the industrial waste shows higher strength than the normal concrete and hence this industrial waste can be used as fine aggregate in concrete.

  7. Activity of Reducing Steel Slag of EAF

    GUO Chinhsiang; HWANG Chaolung; LIN Tingyi


    Reducing steel slag (RSS) was mainly acquired from five electric-arc furnace (EAF)steelmaking plants (among them, the products of two plants were carbon steel and those of other plants were stainless steel) for research tests. The chemical properties, compound compositions, activities and contents of main expansive compounds were tested. The results showed that the field sampled RSS had a very high crystallinity and hydraulicity with main chemical compositions close to those of Portland cement. It can be known from the study that in case of C/S ratio higher than 2.0, the main compound compositions are C2S, C3S, C2F and f-CaO. However, after the RSS was stored for six months, an obvious variation occurred with potential pre-hydration in RSS, where the SO3 content was slightly reduced and the compressive activity index was obviously higher than that at the 28th day.

  8. Study on treating eutrophic seawater with "steel slag-Gracilaria lemaneiformis" system%钢渣-龙须菜系统处理富营养化海水的研究

    王军; 史云娣; 唐丽; 汝少国


    分别研究了钢渣、龙须菜和钢渣-龙须菜等系统对富营养化海水中硝酸盐、磷酸盐的去除效果,探讨了利用钢渣-龙须菜系统处理富营养化海水的可行性.结果表明,钢渣可有效去除富营养化海水中的磷酸盐,不能去除海水中的硝酸盐.起始密度为3g/L的龙须菜对轻度富营养化海水(硝酸盐:0.3~0.6mg/L,磷酸盐:0,05~0.1mg/L)中硝酸盐、磷酸盐的去除率较高,但是对重度富营养化海水(硝酸盐:4.8mg/L,磷酸盐:0.8mg/L)中硝酸盐、磷酸盐的去除率较低.钢渣.龙须菜系统将钢渣对磷酸盐的物理吸附、化学沉淀与龙须菜对硝酸盐、磷酸盐的生物吸收结合起来,能够显著降低富营养化海水中硝酸盐、磷酸盐的浓度.%Eutrophic seawater was treated with steel slag, Gracilaria lemaneiformis, and 'steel slag-Gracilaria lemaneiformis' system, respectively, and the feasibility of using steel slag for eutrophic seawater treatment was discussed.The results showed that, most phosphorus in the eutrophic seawater was removed by steel slag, while steel slag had no significant effect on nitrogen removement.When Gracilaria lemaneiformis with an initial density of 3g/L was used to treat mildly eutrophic seawater, in which concentration of nitrogen and phosphorus was 0.3~0.6mg/L, and 0.05~0.1mg/L, respectively, the removal rate of nitrogen and phosphorus is high.However, a low-removal rate of nitrogen and phosphorus was found in seriously eutrophic seawater (concentration of nitrogen was 4.8mg/L, and level of phosphorus was 0.8mg/L) treatment with Gracilaria lemaneiformis.And the 'steel slag-Gracilaria lemaneiformis' system obviously reduced nitrogen and phosphorus levels in eutrophic seawater, due to pthehysical adsorption and chemical precipitation of phosphorus by steel slag and the biological uptake of phosphorus and nitrogen by Gracilaria lemaneiformis.

  9. Experimental Investigation and Modeling of Copper Smelting Slags

    Starodub, Konstantin; Kuminova, Yaroslava; Dinsdale, Alan; Cheverikin, Vladimir; Filichkina, Vera; Saynazarov, Abdukahhar; Khvan, Alexandra; Kondratiev, Alex


    Effective extraction of copper from sulfide ores requires careful operation of a copper smelter, which in turn depends very much on chemistry of the feed and resulted slag and matte. For example, chemical composition of copper smelting slags has to be in a certain range to ensure that their properties are within specific limits. Disobeying these rules may lead to complications in smelting operation, poor quality of the copper products, and premature shutdown of the copper smelter. In the present paper the microstructure and phase composition of slags from the Almalyk copper flash smelter were investigated experimentally and then modeled thermodynamically to evaluate potential ways of improvement and optimization of the copper smelting process and its products. The slag samples were taken at different stages of the copper smelting process: on slag tapping, after slag transportation to a deposition site, and at the site. Experimental investigation included the XRD, XRF, and SEM techniques, which were also confirmed by the traditional wet chemistry analysis. Thermodynamic modeling was carried out using thermochemical software package MTDATA, which enables thermodynamic and physical properties of the matte, slag, and gas phases to be calculated in a wide range of temperatures, pressures, and chemical compositions. In addition, slag viscosities and corresponding matte settling rates were estimated using the modified Urbain and Utigard-Warczok models, and the Hadamard-Rybczynski equation, respectively. It was found that the copper content in the slags may vary significantly depending on the location of slag sampling. Cu was found to be present as sulfide particles, almost no Cu was found to be dissolved in the slag. Analysis of microstructure and phase composition showed that major phase found in the samples is fayalite, while other phases are complex spinels (based on magnetite), different sulfides, and a glass-like phase. Thermodynamic calculations demonstrated the

  10. Effects of long-term fertilization on weed community characteristics and carbon, nitrogen and phosphorus stoichiometry during winter-spring season in yellow-clay paddy fields of South China%长期施肥对南方黄泥田冬春季杂草群落及其C、N、P化学计量的影响

    林新坚; 王飞; 王长方; 林诚; 李清华; 何春梅; 李昱


    As an important agronomic measure, fertilization affects not only crop growth, but also field weeds and community composition. However, the effects of different fertilization on weed community characteristics are still not fully understood. To that end, a long-term experiment was set up in 1983 at Fujian Experimental Observatory Station, a station for the monitoring (via experimental plots) of long-term farmland conservation practices. The station belongs to the Ministry of Agriculture and is located at 119°04'10" E and 26°13'31" N. The soils at the station are the typical yellow-clay paddy soils originating from foot-slope deposited low-hilly red soils of mid-low-yield paddy fields. The influences of different long-term fertilization schemes on the characteristics of field weed communities and carbon (C), nitrogen (N) and phosphorus (P) stoichiometry during winter-spring seasons were investigated. The main aim was to lay the scientific basis for southern paddy soil fertility improvement and weed management and utilization. The results showed that compared with the control (no fertilization, CK), Shannon uniform index (E) was 0.03—0.07 lower in the treatments of chemical fertilizer plus cattle manure (NPKM), chemical fertilizer plus straw (NPKS) and chemical fertilizer (NPK). Margalef abundant index (DMG) also dropped in NPKM and NPKS treatments. Shannon diversity index (H'), a comprehensive indicator, was 0.02-0.16 lower in fertilization treatments. Compared with CK, weed biomass increased by 89.6%~214.7% in all fertilization treatments. Weed N, P and K contents increased as well, and was most significant for NPKM treatment. In terms of accumulated nutrients, the treatments rank of paddy soils was NPKM > NPKS > NPK. Furthermore, weed C/N and C/P ratios dropped in all fer-tilization treatments. Some significant correlations were noted among weed C/N, C/P and N/P ratios and C/N, C/P, N/P ratios of soil and biomass. Different fertilization schemes influenced weed

  11. Desulfurization ability of refining slag with medium basicity

    Yu, Hui-xiang; Wang, Xin-hua; Wang, Mao; Wang, Wan-jun


    The desulfurization ability of refining slag with relative lower basicity ( B) and Al2O3 content ( B = 3.5-5.0; 20wt%-25wt% Al2O3) was studied. Firstly, the component activities and sulfide capacity ( C S) of the slag were calculated. Then slag-metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution ( L S). Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO-Al2O3-SiO2-MgO system with the basicity of about 3.5-5.0 and the Al2O3 content in the range of 20wt%-25wt% has high activity of CaO ( a CaO), with no deterioration of C S compared with conventional desulfurization slag. The measured L S between high-strength low-alloyed (HSLA) steel and slag with a basicity of about 3.5 and an Al2O3 content of about 20wt% and between HSLA steel and slag with a basicity of about 5.0 and an Al2O3 content of about 25wt% is 350 and 275, respectively. The new slag with a basicity of about 3.5-5.0 and an Al2O3 content of about 20wt% has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.

  12. Slagging and Fouling Characteristics of HRSG for Ferrosilicon Electric Furnaces


    The slagging and fouling characteristics of the heat recovery steam generator (HRSG) for ferrosilicon electric furnaces are discussed in this paper. Three ash samples were taken from the HRSG of a ferrosilicon furnace in Ningxia Province, China, which suffered from serious slagging and fouling. X-ray fluorescence (XRF), X-ray powder diffraction (XRD) and scanning electron microscope (SEM) were used to analyze the ash samples. The results show that low melting point salt Na 2 SO 4 and composit...

  13. Preparation of Glass Ceramic Based on Granulated Slag and Cullet


    The glass-ceramic was prepared on the basis of materials of granulated slag containing high-calcium oxide and cullet.The content of granulated slag ranges from 50%-60%wt in the glass compositions. The samples were analyzed by DTA, SEM and XRD.The results show that the main crystal phase of the glass-ceramic is β-CaSiO3,Which is in scattering fiber or column form.The applying properties have also been measured.

  14. Chloride ion transport performance in slag mortar under fatigue loading

    WANG CaiHui; SUN Wei; JIANG JinYang; HAN JianDe; YE BangTu


    The transport performance of chloride ion in slag cement mortar was investigated experimentally.In the self-designed experiment,fatigue loading was coupled simultaneously with ion transportation process,the diffusion law of chloride ion was obtained by titration and the AE (acoustic emission) technique was employed to detect the real-time damage distribution in the mortar specimen.The results for fatigue stress levels of 0.3,0.4 and 0.5 and slag contents of 0,10%,30% and 50% showed that fatigue loading accelerated the diffusion of chloride ion in mortar and the acceleration effect increased with the increase in stress levels.Slag addition was found to improve anti-chloride ion erosion performance effectively with the best substitution level at 30%,because the inhibition effect of slag on chloride ion diffusion diminished when the slag content exceeded 30%.The comparative experiments indicated that dynamic load has a significant effect on the transport performance of chloride ion in slag cement mortar.

  15. Stabilization of Black Cotton Soil Using Micro-fine Slag

    Shukla, Rajesh Prasad; Parihar, Niraj Singh


    This work presents the results of laboratory tests conducted on black cotton soil mixed with micro-fine slag. Different proportions of micro-fine slag, i.e., 3, 6, 9, 12 and 15 % were mixed with the black cotton soil to improve soil characteristics. The improvement in the characteristics of stabilized soil was assessed by evaluating the changes in the physical and strength parameters of the soil, namely, the Atterberg limits, free swell, the California Bearing Ratio (CBR), compaction parameters and Unconfined Compressive Strength (UCS). The mixing of micro-fine slag decreases the liquid limit, plasticity index and Optimum Moisture Contents (OMC) of the soil. Micro-fine slag significantly increases the plastic limit, UCS and CBR of the soil up to 6-7 % mixing, but mixing of more slag led to decrease in the UCS and CBR of the soil. The unsoaked CBR increased by a substantial amount unlike soaked CBR value. The swell potential of the soil is reduced from medium to very low. The optimum amount of micro-fine slag is found to be approximately 6-7 % by the weight of the soil.

  16. Growth promotion effect of steelmaking slag on Spirulina platensis

    Nogami, R.; Tam, L. T.; Anh, H. T. L.; Quynh, H. T. H.; Thom, L. T.; Nhat, P. V.; Thu, N. T. H.; Hong, D. D.; Wakisaka, M.


    A growth promotion effect of steelmaking slag on Spirulina platensis M135 was investigated. The growth promotion effect was obtained that was 1.27 times greater than that obtained by the control by adding 500 mg L-1 of steelmaking slag and culturing for 60 days. The lipid content decreased in a concentration-dependent manner with steelmaking slag, whereas the carbohydrate content remained constant. The protein content of S. platensis M135 increased in a concentration-dependent manner with steelmaking slag when cultured at day 45. The superoxide dismutase activity of S. platensis M135 exhibited a decreasing trend in a time-dependent manner and an increasing trend in the control. The superoxide dismutase activity was lower than that of the control at day 1 but was higher at day 30. No genetic damage was observed up to 500 mg L-1 of steelmaking slag at 30 days of culture. Recovery from genetic damage was observed at 1,000 mg L-1 of steelmaking slag but not at higher concentrations.

  17. Recovery of copper and cobalt from ancient slag.

    Bulut, Gülay


    About 2.5 million tonnes of copper smelter slag are available in Küre, northern part of Turkey. This slag contains large amounts of metallic values such as copper and cobalt. A representative slag sample containing 0.98% Cu, 0.49% Co and 51.47% Fe was used in the experimental studies. Two different methods, direct acid leaching and acid baking followed by hot water leaching were used for recovering Cu and Co from the slag. The effects of leaching time, temperature and acid concentration on Cu- and Co-dissolving efficiencies were investigated in the direct acid leaching tests. The optimum leaching conditions were found to be a leaching time of 2 h, acid concentration of 120 g L(-1), and temperature of 60 degrees C. Under these conditions, 78% Cu and 90% Co were extracted. In the acid baking + hot water leaching tests, 74% Co was dissolved after 1 h of roasting at 200 degrees C using a 3:1 acid:slag ratio, whereas the Cu-dissolving efficiency was 79% and the total slag weight loss was approximately 50%.

  18. Effect of factors on the extraction of boron from slags

    Zhang, Peixin; Sui, Zhitong


    The effects of slag composition, additive agent, and heat treatment on the crystal morphologies, the crystallization behavior, and the efficiency of extraction of boron (EEB) from slags were investigated by chemical analysis, polarization microscope, and X-ray diffraction (XRD) as well as differential thermal analysis (DTA). The EEB varied with the slag composition. The farther the slag composition deviated from the line between 2MgO · B2O3 and 2MgO · SiO2 in the MgO-B2O3-SiO2 system, the lower the EEB. The EEB was directly related to the precipitating characteristics of the boron component in the slags. The EEB was high if the boron component existed in the form of a crystalline phase, otherwise the EEB was low when boron was in the form of an amorphous phase. The EEB from MgO-Al2O3-CaO-B2O3-SiO2 slag varied with the temperature of heat treatment; the highest EEB appeared at 1100 °C. The EEB and the crystallinities were increased by addition of TiO2 and MOx (M = Mg, Ca, Fe, Si). The effect of MOx was more notable than that of TiO2.

  19. Portland cement-blast furnace slag blends in oilwell cementing applications

    Mueller, D.T.; DiLullo, G.; Hibbeler, J. [and others


    Recent investigations of blast furnace slag cementing technologies. have been expanded to include Portland cement/blast furnace slag blends. Mixtures of Portland cement and blast furnace slag, while having a long history of use in the construction industry, have not been used extensively in oilwell cementing applications. Test results indicate that blending blast furnace slag with Portland cement produces a high quality well cementing material. Presented are the design guidelines and laboratory test data relative to mixtures of blast furnace slag and Portland cements. Case histories delineating the use of blast furnace slag - Portland cement blends infield applications are also included.

  20. Organic chemistry of elemental phosphorus

    Milyukov, V A; Budnikova, Yulia H; Sinyashin, Oleg G [A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences, Kazan (Russian Federation)


    The principal achievements and the modern trends in the development of the chemistry of elemental phosphorus are analysed, described systematically and generalised. The possibilities and advantages of the preparation of organophosphorus compounds directly from white phosphorus are demonstrated. Attention is focused on the activation and transformation of elemental phosphorus in the coordination sphere of transition metal complexes. The mechanisms of the reactions of white phosphorus with nucleophilic and electrophilic reagents are discussed. Electrochemical approaches to the synthesis of organic phosphorus derivatives based on white phosphorus are considered.

  1. Carbothermic Reduction Reactions at the Metal-Slag Interface in Ti-Bearing Slag from a Blast Furnace

    Wang, Yao-Zu; Zhang, Jian-Liang; Liu, Zheng-Jian; Du, Cheng-Bo


    Carbothermic reduction reactions at the metal-slag interface and the mechanisms of iron loss during the smelting of vanadium-bearing titanomagnetite in a blast furnace are still not clear as a result of the limited ability to observe the high-temperature zone of a blast furnace. The chemical composition of a Ti-bearing slag was determined by x-ray fluorescence and x-ray diffraction. The interfaces were characterized by scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy. The interfacial chemical reactions were deduced based on the characterization results and on the thermodynamic calculations performed using Factsage 6.4. The results indicated that the forms of iron in the slag were iron droplets wetted by Ti(C x , N1-x ), mechanically separated by iron and iron oxide. The different forms possessed unique characteristics and were formed by different mechanisms. Iron droplets wetted by Ti(C x , N1-x ) were generated through a series of interfacial reactions between TiO2 in the slag and [C] and [N] in the metal. Iron droplets without attached Ti(C x , N1-x ) were mainly located on the edges of pores and were attributed to the reduction of Fe x O in the slag. Insufficient reduction of iron-bearing minerals made it difficult for iron droplets to aggregate and separate from the slag, which created an Fe x O-enriched zone.

  2. Low Phosphorus Diet: Best for Kidney Disease?

    ... diet: Best for kidney disease? Why is a low-phosphorus diet useful in managing kidney disease? What ... choose foods that are lower in phosphorus. Choose low-phosphorus foods The best way to limit phosphorus ...

  3. Molybdate adsorption from steel slag eluates by subsoils.

    Matern, K; Rennert, T; Mansfeldt, T


    Steel slags are industrial by-products which are generated in large amounts worldwide, e.g. 150-230×10(6) Mg in 2012, and which are partly used for construction. Molybdenum (Mo) can be added during steel processing in order to harden the steel. The objective of this study was to evaluate the adsorption behaviour of molybdate (MoO4(2-)) from slag eluates in subsoils. Molybdate batch adsorption experiments were carried out with eluates obtained from two different kinds of steel slags (i) LD slag (Linz-Donawitz operation, LDS) and (ii) electric arc furnace slag (EAF) to assess the risk that may arise from the contamination of groundwater by the leaching of molybdate. Six different subsoils were chosen in order to provide a wide range of chemical properties (pH 4.0-7.6; dithionite-extractable Fe 0.73-14.7 g kg(-1)). Molybdate adsorption experiments were carried out at the pH of the steel slag eluates (pH 11-12) as well as at pH values adjusted to the soil pH. The data were evaluated with the Freundlich equation. Molybdate adsorption exhibited a maximum near pH 4 for steel slag eluates adjusted to the soil pH, and decreased rapidly with increasing pH until adsorption was virtually zero at pH>11. Adsorption was greater for soils with high amounts of dithionite-extractable Fe oxides. The extent and behaviour of molybdate adsorption from both eluates was similar. After a reaction time of 24h, the pH of the EAF slag eluate was lower than that of the LD steel slag eluate, which was caused by different acid buffer capacities. Some soils were able to decrease the pH of the EAF slag eluates by about 4 pH units, enhancing the adsorption of molybdate. Transport simulations indicated that molybdate discharge is low in acidic soils.

  4. Febre amarela Yellow fever

    Pedro Fernando da Costa Vasconcelos


    Full Text Available A febre amarela é doenca infecciosa não-contagiosa causada por um arbovírus mantido em ciclos silvestres em que macacos atuam como hospedeiros amplificadores e mosquitos dos gêneros Aedes na África, e Haemagogus e Sabethes na América, são os transmissores. Cerca de 90% dos casos da doença apresentam-se com formas clínicas benignas que evoluem para a cura, enquanto 10% desenvolvem quadros dramáticos com mortalidade em torno de 50%. O problema mostra-se mais grave em África onde ainda há casos urbanos. Nas Américas, no período de 1970-2001, descreveram-se 4.543 casos. Os países que mais diagnosticaram a doença foram o Peru (51,5%, a Bolívia (20,1% e o Brasil (18,7%. Os métodos diagnósticos utilizados incluem a sorologia (IgM, isolamento viral, imunohistoquímica e RT-PCR. A zoonose não pode ser erradicada, mas, a doença humana é prevenível mediante a vacinação com a amostra 17D do vírus amarílico. A OMS recomenda nova vacinação a cada 10 anos. Neste artigo são revistos os principais conceitos da doença e os casos de mortes associados à vacina.Yellow fever is an infectious and non-contagious disease caused by an arbovirus, the yellow fever virus. The agent is maintained in jungle cycles among primates as vertebrate hosts and mosquitoes, especially Aedes in Africa, and Haemagogus and Sabethes in America. Approximately 90% of the infections are mild or asymptomatic, while 10% course to a severe clinical picture with 50% case-fatality rate. Yellow fever is largely distributed in Africa where urban epidemics are still reported. In South America, between 1970-2001, 4,543 cases were reported, mostly from Peru (51.5%, Bolivia (20.1% and Brazil (18.7%. The disease is diagnosed by serology (detection of IgM, virus isolation, immunohistochemistry and RT-PCR. Yellow fever is a zoonosis and cannot be eradicated, but it is preventable in man by using the 17D vaccine. A single dose is enough to protect an individual for at least

  5. Quantitative Chemical Analysis of Slag Ash of Novocherkassk State District Power Plant

    Tatyana Germanovna Korotkova


    Full Text Available Quantitative chemical composition of ash and slag mix generated upon combustion of Donetsk culm is determined. It is established that ash and slag mix of Novocherkassk state district power plant (SDPP (Rostov region, Russia after coal combustion has the following composition: iron – 2.3%; mineral constituents – 75.8%; calcium oxide – 20.4%; aluminum oxide – 0.0118%; water – 1.3022%; manganese oxide – 0.18%; copper oxide – 0.0043%; plumbum – 0.0017%; it is qualified as hazard class IV for environment. Cadmium, mercury, arsenic, selenium, antimony, bismuth are contained in trace amounts < 0.1 mg/kg. In order to reduce dust emissions the cleaning stage I of gas scrubbing facility is equipped with group cyclone comprised of four cyclone units. Medium and coarse particles under the action of centrifugal force are deposited in the cyclone. This promoted decrease in dust load on bag filters, the cleaning stage II. Qualitative chemical composition of ash captured by group cyclone and that of ash captured by bag filter are determined. Cadmium, copper, plumbum, zinc, iron, manganese, and calcium are contained in coarse and fine particles captured by group cyclone and bag filter. Aluminum referred to light metals is completely captured by cyclone. The ash dust in its bulk is of dark gray color. The ash captured by cyclone contains coarse particles of black color and the ash captured bag filter contains fine particles of light colors (gray-yellow color producing silky gloss. This is characteristic for ash dust after combustion of Donetsk culm. The main component of the ash is silicon dioxide, its content in the ash captured by filter reaches 91%. These fine particles create light tone of this ash.

  6. Mineral precipitation and dissolution at two slag-disposal sites in northwestern Indiana, USA

    Bayless, E.R.; Schulz, M.S.


    Slag is a ubiquitous byproduct of the iron- and steel-refining industries. In northwestern Indiana and northeastern Illinois, slag has been deposited over more than 52 km2 of land surface. Despite the widespread use of slag for fill and construction purposes, little is known about its chemical effects on the environment. Two slagdisposal sites were examined in northwestern Indiana where slag was deposited over the native glacial deposits. At a third site, where slag was not present, background conditions were defined. Samples were collected from cores and drill cuttings and described with scanning electron microscopy and electron microprobe analysis. Ground-water samples were collected and used to assess thermodynamic equilibria between authigenic minerals and existing conditions. Differences in the mineralogy at background and slag-affected sites were apparent. Calcite, dolomite, gypsum, iron oxides, and clay minerals were abundant in native sediments immediately beneath the slag. Mineral features indicated that these minerals precipitated rapidly from slag drainage and co-precipitated minor amounts of non-calcium metals and trace elements. Quartz fragments immediately beneath the slag showed extensive pitting that was not apparent in sediments from the background site, indicating chemical weathering by the hyperalkaline slag drainage. The environmental impacts of slag-related mineral precipitation include disruption of natural ground-water flow patterns and bed-sediment armoring in adjacent surface-water systems. Dissolution of native quartz by the hyperalkaline drainage may cause instability in structures situated over slag fill or in roadways comprised of slag aggregates.

  7. Analysis of the Optimum Usage of Slag for the Compressive Strength of Concrete.

    Lee, Han-Seung; Wang, Xiao-Yong; Zhang, Li-Na; Koh, Kyung-Taek


    Ground granulated blast furnace slag is widely used as a mineral admixture to replace partial Portland cement in the concrete industry. As the amount of slag increases, the late-age compressive strength of concrete mixtures increases. However, after an optimum point, any further increase in slag does not improve the late-age compressive strength. This optimum replacement ratio of slag is a crucial factor for its efficient use in the concrete industry. This paper proposes a numerical procedure to analyze the optimum usage of slag for the compressive strength of concrete. This numerical procedure starts with a blended hydration model that simulates cement hydration, slag reaction, and interactions between cement hydration and slag reaction. The amount of calcium silicate hydrate (CSH) is calculated considering the contributions from cement hydration and slag reaction. Then, by using the CSH contents, the compressive strength of the slag-blended concrete is evaluated. Finally, based on the parameter analysis of the compressive strength development of concrete with different slag inclusions, the optimum usage of slag in concrete mixtures is determined to be approximately 40% of the total binder content. The proposed model is verified through experimental results of the compressive strength of slag-blended concrete with different water-to-binder ratios and different slag inclusions.

  8. Characterization of Ladle Furnace Slag from Carbon Steel Production as a Potential Adsorbent

    Ankica Rađenović


    Full Text Available A promising type of steel slag for applications is the ladle furnace (LF slag, which is also known as the basic slag, the reducing slag, the white slag, and the secondary refining slag. The LF slag is a byproduct from further refining molten steel after coming out of a basic oxygen furnace (BOF or an electric arc furnace (EAF. The use of the LF slag in further applications requires knowledge of its characteristics. The LF slag characterization in this paper has been performed using the following analytical methods: chemical analysis by energy dispersive spectrometry (EDS, mineralogical composition by X-ray diffraction (XRD, surface area properties by the Brunauer-Emmett-Teller (BET and the Barrett-Joyner-Halenda (BJH methods, surface chemistry by infrared absorption (FTIR spectroscopy, and morphological analysis by scanning electron microscopy (SEM. The results showed that the main compounds are calcium, silicon, magnesium, and aluminium oxides, and calcium silicates under their various allotropic forms are the major compounds in the LF slag. Surface area properties have shown that the LF slag is a mesoporous material with relatively great BET surface area. The ladle furnace slag is a nonhazardous industrial waste because the ecotoxicity evaluation by its eluate has shown that the LF slag does not contain constituents which might in any way affect the environment harmfully.

  9. III. Quantitative aspects of phosphorus excretionin ruminants

    Bravo, David; Sauvant, Daniel; Bogaert, Catherine; Meschy, François


    International audience; Ruminant phosphorus excretion and metabolism were studied through a database. Faecal endogenous phosphorus is the main pathway of phosphorus excretion and averages 0.85 of total faecal phosphorus. The remaining 0.15 is unabsorbed dietary phosphorus. Faecal endogenous phosphorus is mainly unabsorbed phosphorus, with saliva being the major source, and is correlated to factors influencing saliva secretion (DM intake, physical dietary characteristics and dietary phosphorus...

  10. Why is my alfalfa yellow?

    In 2016, many parts of the Midwest experienced far wetter than normal summer weather and by August or September, many growers were asking, “Why is my alfalfa yellow?” When all or part of an alfalfa field is yellow, it is a certain sign that something has gone wrong. In this case the problem in most ...

  11. The Red and the Yellow



    THE China film market is based on the so-called battle of the yellow, green and red.Yellow is American Kodak,green Japanese Fuji color, and red China's Lucky film, local counterweight to the two world-famous foreigners.

  12. Photo yellowing of human hair.

    Nogueira, A C S; Richena, M; Dicelio, L E; Joekes, I


    In general, human hair is claimed to turn yellower after sun exposure. This is particularly affirmed for white hair. However, quantitative data relating yellowness to hair type and to the radiation wavelength are missing. This work shows results of the effect of full or UVB-filtered radiation of a mercury vapor or a xenon-arc lamp on the yellowness of virgin white, dark-brown, blond and red hair. All hair types showed a substantial change in yellowness after irradiation, which is dependent on the hair type and radiation wavelength. Surprisingly, white hair turns less yellow after both full and UVB-filtered radiation exposure. This effect is more pronounced when UVB is filtered from the radiation system. The only radiation that shows a photo-yellowing effect on white hair is infrared. As the yellowness of white hair is commonly related to tryptophan degradation, fluorescence experiments with hair solutions were performed to identify the natural degradation of tryptophan which occurs in hair after light irradiation. Pigmented hairs were also studied, as well as hair treated with a bleaching solution. Although we observe a decrease in tryptophan content of hair after lamp radiation, a direct correlation with hair yellowness was not achieved. Results are discussed in terms of hair type, composition and melanin content.

  13. Slagging and Fouling Characteristics of HRSG for Ferrosilicon Electric Furnaces

    Yungang Wang


    Full Text Available The slagging and fouling characteristics of the heat recovery steam generator (HRSG for ferrosilicon electric furnaces are discussed in this paper. Three ash samples were taken from the HRSG of a ferrosilicon furnace in Ningxia Province, China, which suffered from serious slagging and fouling. X-ray fluorescence (XRF, X-ray powder diffraction (XRD and scanning electron microscope (SEM were used to analyze the ash samples. The results show that low melting point salt Na2SO4 and composite salts Na (AlSi3O8 and 3K2SO4·CaSO4 deposit on the superheater tube walls in aerosol form and solidify to form the initial slag layer. With the continuous deposition of the low melting point compounds, more and more ash particles in the flue gas adhere to the slag surface to form a thicker slag. Low melting point composite salt NaO·Al2O3·SiO2 is absorbed on the evaporator tube walls in aerosol form. With the deposition of NaO·Al2O3·SiO2, more and more ash particles are absorbed to form the fouling. Since there is less space between pin-finned tubes, the large iron-rich slag particles are easily deposited on tube walls and fin surfaces, which is advantageous to the fouling process. There are large quantities of superfine ash particles in the flue gas that easily adhere to other particles or tube walls, which facilitates the slagging and fouling process.

  14. Desulfurization ability of refining slag with medium basicity

    Hui-xiang Yu; Xin-hua Wang; Mao Wang; Wan-jun Wang


    The desulfurization ability of refining slag with relative lower basicity (B) and Al2O3 content (B=3.5−5.0;20wt%−25wt%Al2O3) was studied. Firstly, the component activities and sulfide capacity (CS) of the slag were calculated. Then slag−metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution (LS). Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO−Al2O3−SiO2−MgO system with the basicity of about 3.5−5.0 and the Al2O3 content in the range of 20wt%−25wt%has high activity of CaO (aCaO), with no deterioration of CS compared with conventional desulfurization slag. The measured LS between high-strength low-alloyed (HSLA) steel and slag with a basicity of about 3.5 and an Al2O3 content of about 20wt%and between HSLA steel and slag with a basicity of about 5.0 and an Al2O3 content of about 25wt%is 350 and 275, respectively. The new slag with a basicity of about 3.5−5.0 and an Al2O3 content of about 20wt%has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.

  15. phosphorus retention data and metadata

    U.S. Environmental Protection Agency — phosphorus retention in wetlands data and metadata. This dataset is associated with the following publication: Lane , C., and B. Autrey. Phosphorus retention of...

  16. Investigation on Viscosity and Nonisothermal Crystallization Behavior of P-Bearing Steelmaking Slags with Varying TiO2 Content

    Wang, Zhanjun; Sun, Yongqi; Sridrar, Seetharaman; Zhang, Mei; Zhang, Zuotai


    The viscous flow and crystallization behavior of CaO-SiO2-MgO-Al2O3-FetO-P2O5-TiO2 steelmaking slags have been investigated over a wide range of temperatures under Ar (High purity, >99.999 pct) atmosphere, and the relationship between viscosity and structure was determined. The results indicated that the viscosity of the slags slightly decreased with increasing TiO2 content. The constructed nonisothermal continuous cooling transformation (CCT) diagrams revealed that the addition of TiO2 lowered the crystallization temperature. This can mainly be ascribed to that addition of TiO2 promotes the formation of [TiO6]-octahedra units and, consequently, the formation of MgFe2O4-Mg2TiO4 solid solution. Moreover, the decreasing viscosity has a significant effect on enhancing the diffusion of ion units, such as Ca2+ and [TiO4]-tetrahedra, from bulk melts to the crystal-melt interface. The crystallization of CaTiO3 and CaSiTiO5 was consequently accelerated, which can improve the phosphorus content in P-enriched phase ( n2CaO·SiO2-3CaO·P2O5). Finally, the nonisothermal crystallization kinetics was characterized and the activation energy for the primary crystal growth was derived such that the activation energy increases from -265.93 to -185.41 KJ·mol-1 with the addition of TiO2 content, suggesting that TiO2 lowered the tendency for the slags to crystallize.

  17. Skid resistance performance of asphalt wearing courses with electric arc furnace slag aggregates.

    Kehagia, Fotini


    Metallurgical slags are by-products of the iron and steel industry and are subdivided into blast furnace slag and steel slag according to the different steel-producing processes. In Greece, slags are mostly produced from steelmaking using the electric arc furnace process, and subsequently are either disposed in a random way or utilized by the cement industry. Steel slag has been recently used, worldwide, as hard aggregates in wearing courses in order to improve the skidding resistance of asphalt pavements. At the Highway Laboratory, Department of Civil Engineering of Aristotle University of Thessaloniki research has been carried out in the field of steel slags, and especially in electric arc furnace (EAF) slag, to evaluate their possible use in highway engineering. In this paper, the recent results of anti-skidding performance of steel slag aggregates in highway pavements are presented.

  18. Influence of Basicity and MgO on Fluidity and Desulfurization Ability of High Aluminum Slag

    Wang, Ping; Meng, Qing-min; Long, Hong-ming; Li, Jia-xin


    The viscosity of experimental slag, which was mixed based on the composition of a practical blast furnace slag, was measured in this paper. The influence of Al2O3 and MgO content, basicity R2 = w(CaO)/w(SiO2) on the fluidity of slag was studied. The stepwise regression analysis in SPSS was used to reveal the relationship between sulfur distribution coefficient LS and slag composition as well as furnace temperature. The results show that increasing of MgO up to 12% can decrease the slag viscosity. The w(MgO) should be controlled below 8% when there is 20% Al2O3 in the slag. Temperature of hot metal and content of CaO in slag are the two dominant factors on the desulfurization capacity of slag.

  19. Steel Slag as an Iron Fertilizer for Corn Growth and Soil Improvement in a Pot Experiment

    WANG Xian; CAI Qing-Sheng


    The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1)of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.

  20. Reactions Between MgO-C Refractory, Molten Slag and Metal

    Li, Zushu; Mukai, Kusuhiro; Tao, Zainan


    The behavior of MgO-C refractory-slag-metal system, which is caused by the reactions such as the dissolution of MgO and graphite in the refractory into slag and metal respectively and the generation...

  1. Plant Growth and Water Purification of Porous Vegetation Concrete Formed of Blast Furnace Slag, Natural Jute Fiber and Styrene Butadiene Latex

    Hwang-Hee Kim


    Full Text Available The purpose of this study is to investigate porous vegetation concrete formed using the industrial by-products blast furnace slag powder and blast furnace slag aggregates. We investigated the void ratio, compressive strength, freeze–thaw resistance, plant growth and water purification properties using concretes containing these by-products, natural jute fiber and latex. The target performance was a compressive strength of ≥12 MPa, a void ratio of ≥25% and a residual compressive strength of ≥80% following 100 freeze–thaw cycles. Using these target performance metrics and test results for plant growth and water purification, an optimal mixing ratio was identified. The study characterized the physical and mechanical properties of the optimal mix, and found that the compressive strength decreased compared with the default mix, but that the void ratio and the freeze–thaw resistance increased. When latex was used, the compressive strength, void ratio and freeze–thaw resistance all improved, satisfying the target performance metrics. Vegetation growth tests showed that plant growth was more active when the blast furnace slag aggregate was used. Furthermore, the use of latex was also found to promote vegetation growth, which is attributed to the latex forming a film coating that suppresses leaching of toxic components from the cement. Water purification tests showed no so significant differences between different mixing ratios; however, a comparison of mixes with and without vegetation indicated improved water purification in terms of the total phosphorus content when vegetation had been allowed to grow.

  2. Phosphorus derivatives of salicylic acid

    Chvertkina, L. V.; Khoklov, P. S.; Mironov, Vladimir F.


    The present state of work on the methods of synthesis, chemical properties, and practical applications of phosphorus-containing derivatives of salicylic acid has been reviewed. The characteristics of the chemical transformations of cyclic and acyclic phosphorus derivatives of salicylic acid related to the coordination state of the phosphorus atom have been examined. The bibliography includes 158 references.


    Noguchi, Hideyo


    Analysis of the records of instances in which non-immune persons contracted yellow fever notwithstanding vaccination shows that the onset of disease occurs soon after vaccination, the longest period being 13 days. Since the average incubation period in yellow fever is 6 days, it seems that infection must have taken place in some instances during the period while protection was developing. These instances led to a study of the possibility of immediate protection by means of the anti-icteroides serum. It had already been shown that the immune serum protects at once against experimental Leptospira icteroides infection, but it remained to determine how long the protection would last. Guinea pigs were given different quantities of the immune serum and subsequently injected, at various intervals, with a virulent strain of Leptospira icteroides. Complete protection enduring 5 days was obtained with as minute a quantity of serum as 0.002 cc. per 1,000 gm. of body weight. After 5 days, however, the immune substance rapidly diminished, and to keep the animal protected for as long as 10 days it was necessary to give 100 times as much, or 0.2 cc. For a man weighing 80 kilos, 0.16 cc. (0.002 x 80) would theoretically be sufficient to protect for at least 5 days, 1.6 cc. for 7 days, and 16 cc. for 10 days. This temporary protection may be a valuable antecedent to that furnished by vaccination, since the final effect of the latter cannot be expected until at least 9 to 10 days have passed. PMID:19868677

  4. Experiments and evidences:jellyfish (Nemopilema nomurai) decomposing and nutrients (nitrogen and phosphorus) released

    LI Xuegang; SONG Jinming; MA Qingxia; LI Ning; YUAN Huamao; DUAN Liqin; QU Baoxiao


    The aim of this study was to investigate nitrogen and phosphorus released in the process of the decomposition of giant jellyfish in the laboratory and found the evidence to verify the influence of nutrients released by the decomposition of jellyfish on the ecosystem in the field. The release of nitrogen and phosphorus from the decomposition ofNemopilema nomurai was examined in a series of experiments under different incubation conditions such as different pH values, salinity values, temperatures and nitrogen and phosphorus concentrations. The results showed that the complete decomposition ofNemopilema nomurai generally took about 4–8 d. The release of nitrogen and phosphorus from the decomposition ofNemopilema nomurai could be divided into two stages: the early stage and the later stage, although the efflux rate of nitrogen was one order more than phosphorus. In the early stage of the decomposition ofNemopilema nomurai, the concentrations of dissolved nitrogen, dissolved phosphorus, total nitrogen and total phosphorus in seawater increased rapidly, and the concentration of nitrogen could reach the highest level in the whole degradation process. In the later stage of the decomposition, the concentrations of dissolved nitrogen and total nitrogen declined slowly, while the concentration of phosphorus in water could reach a maximum in the degradation process. High pH, low salinity, high temperature and N/P will promote the release of nitrogen; low pH is unfavorable to the release of nitrogen but favorable to the release of phosphorus. In addition, we found the concentrations of ammonium and phosphate in the bottom water were higher than those in the surface water during the period of jellyfish bloom in the Jiaozhou Bay, proving that nutrients released by the decomposition of jellyfish have significant influence on nitrogen and phosphorus in the field. For the whole Yellow Sea, nutrients released by jellyfish carcasses may reach up to (2.63±2.98)×107 mol/d of

  5. Development of Glass Ceramics Made From Ferrous Tailings and Slag in China

    LIU Cheng-jun; SHI Pei-yang; ZHANG Da-yong; JIANG Mao-fa


    A great amount of ferrous tailings and slag cause severe damage to the ecological environment, which must be reclaimed and utilized. The composition, type, and characteristics of ferrous tailings and slag in China were introduced. The research status and the application outlook of glass ceramics made from ferrous tailings and slag were discussed. Glass ceramics made from ferrous tailings and slag can be applied to various fields, and it will be environmentally conscious materials in the 21st century.

  6. Products of steel slags an opportunity to save natural resources.

    Motz, H; Geiseler, J


    In Germany, and in the most industrial countries, the use of blast furnace and steel slags as an aggregate for civil engineering, for metallurgical use and as fertiliser has a very long tradition. Since the introduction of the basic oxygen steel making furnace (BOF) process and the electric arc furnace (EAF) process the German steel industry started extensive research on the development of fields of application for BOF and EAF slags. These investigations have been mainly performed by Forschungsgemeinschaft Eisenhüttenschlacken e. V. (FEhS), the Research Association for blast furnace and steel slags. Today steel slags are well characterised and long-term experienced materials mainly used as aggregates for road construction (e.g. asphaltic or unbound layers), as armour-stones for hydraulic engineering constructions (e.g. stabilisation of shores), and as fertiliser for agriculture purposes. These multifarious fields of application could only be achieved because the steelworks influence the quality of slags by a careful selection of raw materials and a suitable process route. Furthermore, subsequent procedures like a treatment of the liquid slag, an appropriate heat treatment and a suitable processing have been developed to ensure that the quality of steel slags is always adequate for the end use. Depending on the respective field of application, the suitability of steel slags has to be proven by determining the technical properties, as well as the environmental compatibility. For this reason test methods have been developed to evaluate the technical properties especially the volume stability and the environmental behaviour. To evaluate the volume stability a suitable test (steam test) has been developed and the results from laboratory tests were compared with the behaviour of steel slags under practical conditions, e.g. in a road. To determine the environmental behaviour leaching tests have been developed. In the meanwhile most of these test methods are drafted or

  7. Pyrometallurgical slags as a potential source of selected metals recovery

    K. Nowińska


    Full Text Available Complex analysis of concentration and form of occurrence such metals as Zn, Pb, Fe and Cu in slags formed during a current zinc production in the Imperial Smelting Process (ISP is a possible basis for development of optimal recovery technology. For this purpose studies of slags from the current production of the Shaft Furnace Unit and of the Lead Refining of the “Miasteczko Śląskie” Zinc Smelting Plant were carried out. The studies results show that slags includes high concentrations of: Zn from 0,064 % to 1,680 %, Pb from 10,56 % to 50,71 %, Fe from 0,015 % to 2,576 %, Cu from 7,48 % to 64,95 %, and change in a broad range. This slags show significant heterogeneity, caused by intermetallic phases (Zn - Pb, Cu - Zn, Cu - Pb formed on the surface thereof. It is so possible that slag can be a potential source of this metals recovery.

  8. Preparation of calcium silicate absorbent from iron blast furnace slag.

    Brodnax, L F; Rochelle, G T


    Calcium silicate hydrate (CSH) solids were prepared from hydrated lime and iron blast furnace slag in an aqueous agitated slurry at 92 degrees C. While it was hoped a minimal lime/slag ratio could be used to create near-amorphous CSH, the surface area of the product improved by increasing the lime/slag weight ratio to 2. The addition of gypsum to the lime/slag system dramatically improved the formation of surface area, creating solids with 139 m2/g after 30 hr of reaction when only a minimal amount of lime was present. The SO2 reactivity of solids prepared with gypsum greatly exceeded that of hydrated lime, achieving greater than 70-80% conversion of the alkalinity after 1 hr of reaction with SO2. The use of CaCl2 as an additive to the lime/slag system, in lieu of gypsum, also produced high-surface-area solids, 115 m2/g after 21 hr of reaction. However, the SO2 reactivity of these sorbents was relatively low given the high surface area. This emphasized that the correlation between surface area and SO2 reactivity was highly dependent on the solid phase, which was subsequently dependent on slurry composition.

  9. Nickel, copper and cobalt coalescence in copper cliff converter slag

    Wolf A.


    Full Text Available The aim of this investigation is to assess the effect of various additives on coalescence of nickel, copper and cobalt from slags generated during nickel extraction. The analyzed fluxes were silica and lime while examined reductants were pig iron, ferrosilicon and copper-silicon compound. Slag was settled at the different holding temperatures for various times in conditions that simulated the industrial environment. The newly formed matte and slag were characterized by their chemical composition and morphology. Silica flux generated higher partition coefficients for nickel and copper than the addition of lime. Additives used as reducing agents had higher valuable metal recovery rates and corresponding partition coefficients than fluxes. Microstructural studies showed that slag formed after adding reductants consisted of primarily fayalite, with some minute traces of magnetite as the secondary phase. Addition of 5 wt% of pig iron, ferrosilicon and copper-silicon alloys favored the formation of a metallized matte which increased Cu, Ni and Co recoveries. Addition of copper-silicon alloys with low silicon content was efficient in copper recovery but coalescence of the other metals was low. Slag treated with the ferrosilicon facilitated the highest cobalt recovery while copper-silicon alloys with silicon content above 10 wt% resulted in high coalescence of nickel and copper, 87 % and 72 % respectively.

  10. Investigation of High-Temperature Slag/Copper/Spinel Interactions

    De Wilde, Evelien; Bellemans, Inge; Campforts, Mieke; Guo, Muxing; Blanpain, Bart; Moelans, Nele; Verbeken, Kim


    An important cause for the mechanical entrainment of copper droplets in slags during primary and secondary copper production is their interaction with solid spinel particles, hindering the sedimentation of the copper droplets. In the present study, the interactions between the three phases involved (slag-Cu droplets-spinel solids) were investigated using an adapted sessile drop experiment, combined with detailed microstructural investigation of the interaction zone. An industrially relevant synthetic PbO-CaO-SiO2-Cu2O-Al2O3-FeO-ZnO slag system, a MgAl2O4 spinel particle, and pure copper were examined with electron microscopy after their brief interaction at 1523 K (1250 °C). Based on the experimental results, a mechanism depending on the interlinked dissolved Cu and oxygen contents within the slag is proposed to describe the origin of the phenomenon of sticking Cu alloy droplets. In addition, the oxygen potential gradient across the phases ( i.e., liquid Cu, slag, and spinel) appears to affect the Cu entrainment, as deduced from a microstructural analysis.

  11. Investigation of High-Temperature Slag/Copper/Spinel Interactions

    De Wilde, Evelien; Bellemans, Inge; Campforts, Mieke; Guo, Muxing; Blanpain, Bart; Moelans, Nele; Verbeken, Kim


    An important cause for the mechanical entrainment of copper droplets in slags during primary and secondary copper production is their interaction with solid spinel particles, hindering the sedimentation of the copper droplets. In the present study, the interactions between the three phases involved (slag-Cu droplets-spinel solids) were investigated using an adapted sessile drop experiment, combined with detailed microstructural investigation of the interaction zone. An industrially relevant synthetic PbO-CaO-SiO2-Cu2O-Al2O3-FeO-ZnO slag system, a MgAl2O4 spinel particle, and pure copper were examined with electron microscopy after their brief interaction at 1523 K (1250 °C). Based on the experimental results, a mechanism depending on the interlinked dissolved Cu and oxygen contents within the slag is proposed to describe the origin of the phenomenon of sticking Cu alloy droplets. In addition, the oxygen potential gradient across the phases (i.e., liquid Cu, slag, and spinel) appears to affect the Cu entrainment, as deduced from a microstructural analysis.




    Full Text Available Raising of problem. Currently of particular relevance was given to the matter of introduction in manufacture of building materials and products, resource-saving techniques and technologies; integrated use of raw materials and materials that prevent or significantly reduce their harmful impact on the environment. This allows you to recycle hundreds of thousands of tons of the fiery liquid slags of silicon manganese and to develop effective structural materials that can replace metals, non-metallic building materials of natural origin, concretes, cast stone, plastics and refractories. Purpose. The study of the structure and properties of building materials and products from electric furnace slag of silicon manganese. Conclusion. Slags from the smelting of silicon manganese are classified as acidic. Their lime factor is in the range of 0.47–0.52. The composition of the slag located in the heterogeneous region SiO2 near the line of separation of cristobalite spread to the crystallization of wollastonite, according to the ternary system MnO-CaO-SiO2, which in consideration of their stability, allows the development of technology of building materials (gravel, sand, granulated slag, etc. and products (foundation blocks, road slabs, containers for transportation and storage of hazardous waste, and others.

  13. Preparation of Slag Wool by Integrated Waste-Heat Recovery and Resource Recycling of Molten Blast Furnace Slags: From Fundamental to Industrial Application

    Dawei Zhao


    Full Text Available The present paper investigated the process of the slag wool fabrication using high temperature blast furnace (BF slag modified by coal ash (CA. The liquidus temperature and viscosity of the slag system with different mass ratios of BF slag and CA were measured through an inner cylinder rotation method. The approximate mass ratio used to fabricate the slag wool was therefore determined and slag wool was then successfully prepared with a high-speed air injection method in the laboratory. The effect of mBF/m ratio, slag temperature for injection and air pressure on the preparation of slag wool was systematically investigated. The mechanical and thermal properties were also studied to confirm the long-term working conditions of the slag wool. An industry-scale slag wool production application was established. The energy consumption and the pollutant generation, were analyzed and compared with the traditional production method, which indicated a 70% reduction in energy consumption and a 90% pollution emission decrease.

  14. Size-dependent enrichment of waste slag aggregate fragments abraded from asphalt concrete.

    Takahashi, Fumitake; Shimaoka, Takayuki; Gardner, Kevin; Kida, Akiko


    Authors consider the environmental prospects of using melted waste slag as the aggregate for asphalt pavement. In particular, the enrichment of slag-derived fragments in fine abrasion dust particles originated from slag asphalt concrete and its size dependency were concerned. A series of surface abrasion tests for asphalt concrete specimens, containing only natural aggregates as reference or 30 wt% of substituted slag aggregates, were performed. Although two of three slag-asphalt concretes generated 1.5-3.0 times larger amount of abrasion dust than the reference asphalt concrete did, it could not be explained only by abrasion resistance of slag. The enrichment of slag-derived fragments in abrasion dust, estimated on the basis of the peak intensity of quartz and heavy metal concentrations, had size dependency for all slag-asphalt concretes. Slag-derived fragments were enriched in abrasion dust particles with diameters of 150-1000 μm. Enrichment factors were 1.4-2.1. In contrast, there was no enrichment in abrasion dust particles with diameter less than 75 μm. This suggests that prior airborne-size fragmentation of substituted slag aggregates does not need to be considered for tested slag aggregates when environmental risks of abrasion dust of slag-asphalt pavement are assessed.

  15. Effects of slag and fly ash in concrete in chloride environment

    Polder, R.B.


    This paper addresses experience from The Netherlands with blast furnace slag and fly ash in concrete in chloride contaminated environments, both from the field and the laboratory. Use of slag produced in The Netherlands started in the 1930s and CEM III/B LH HS, with typically 70% slag, became the do

  16. Phosphorus Deficiency in Ducklins

    CuiHengmin; LuoLingping


    20 one-day-old Tianfu ducklings were fed on a natural diet deficient in phosphorus(Ca 0.80%,P 0.366%)for three weeks and examined for signs and lesions.Signs began to appear at the age of one week,and became serous at two weeks.13 ducklings died during the experiment.Morbidity was 100% and mortality was 65%.The affected ducklings mainly showed leg weakness,severe lamencess,deprssion,lack of appetite and stunted growth,The serum alkaline phosphatase activities increased markedly.The serum phosphorus concentration,tibial ash,ash calcium and phosphorus content decreased obviously.At necropsy,maxillae and ribe were soft,and the latter was crooked.Long ones were soft and broke easily.The hypertrophic zone of the growth-plate in the epiphysis of long ones was lengthened and osteoid tissue increased in the metaphyseal spongiosa histopathologically.The above mentioned symptoms and lesions could be prevented by adding phosphorus to the natural deficient diet(up to 0.65%),The relationship between lesions and signs,pathomorphological characterisation and pathogensis were also discussed in this paper.

  17. Phosphate Capacities of CaF2-MgO and CaF2-CaO-MgO Slags

    Akbari, F.; Pickles, C. A.


    Previously published sulphide capacity data and thermodynamic arguments have been employed to calculate the phosphate capacities and the phosphorus partition ratios between a molten carbon saturated iron alloy and binary CaF2-MgO slags and also ternary CaF2 -CaO-MgO slags at 1450 °C. For the CaF2-MgO binary system, a linear relationship was found between the phosphate and the sulphide capacities as follows: log ? = 1.2 log Cs + 25.2. For the ternary CaF2-CaO-MgO system at 1450 °C, the logarithm of the calculated phosphate capacities ranged from 19.47 to 20.15. With the addition of CaO, the phosphate capacities initially increased, reached a maximum and then decreased slightly. The addition of MgO to the CaF2-CaO system resulted in a decrease in the phosphate capacity. The calculated phosphorus partition ratios increased slightly with increasing mole fraction of CaO in the ternary system.

  18. High-Temperatures Rheometric Analysis Of Selected Heterogeneous Slag Systems

    Migas P.


    Full Text Available It is known that the dynamic viscosity coefficient of slag – with an increased titanium compounds content in the reducing conditions of the blast furnace - may rapidly change. The products of the reduction reaction, precipitation and separation of titanium compounds are responsible for the thickening effect of the slag and the problems of permeability of blast furnace, causing anomalies in the dipping zone. The presence of solid components (particles in the melts determines the rheological character of the entire system. Identifying the rheological character of semi-solid slag systems provides opportunities for the development of mathematical modeling of liquid phase flows in a dripping zone of the blast furnace, allowing e.g to indentify the unstable parts of a metallurgical aggregate.

  19. Structure and Vibrational Spectra of Slags Produced from Radioactive Waste

    Malinina, G. A.; Stefanovsky, S. V.


    The structure of the anionic motif of aluminosilicate and aluminoborosilicate glasses containing simulated slags from a solid radioactive waste incinerator was studied by IR and Raman spectroscopy. Spectra of melted slag were consistent with Si-O tetrahedra with various numbers of bridging O ions and Al-O tetrahedra embedded in the Si-O network in the slag vitreous and crystalline phases (nepheline, nagelschmidtite). Vibrations of doubly and triply bound Si-O tetrahedra and Al-O tetrahedra embedded between them were mainly responsible for the spectra as the content of sodium disilicate fl ux and the glass fraction in the materials increased. Addition of sodium tetraborate fl ux caused the appearance of B-O vibrations of predominantly three-coordinate B and a tendency toward chemical differentiation preceding phase separation.

  20. Vanadium removal from LD converter slag using bacteria and fungi.

    Mirazimi, S M J; Abbasalipour, Z; Rashchi, F


    Removal of vanadium from Linz-Donawits (LD) converter slag was investigated by means of three different species of microbial systems: Acidithiobacillus thiooxidans (autotrophic bacteria), Pseudomonas putida (heterotrophic bacteria) and Aspergillus niger (fungi). The bioleaching process was carried out in both one-step and two-step process and the leaching efficiencies in both cases were compared. Formation of inorganic and organic acids during the leaching process caused mobilization of vanadium. In order to reduce toxic effects of the metal species on the above mentioned microorganisms, a prolonged adaptation process was performed. Both bacteria, A. thiooxidans and P. putida were able to remove more than 90% of vanadium at slag concentrations of 1-5 g L(-1) after 15 days. Also, the maximum achievable vanadium removal in the fungal system was approximately 92% at a slag concentration of 1 g L(-1) after 22 days.

  1. Effects of slag fineness on durability of mortars


    In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS)replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects,exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Consequently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.

  2. Pyrochemical recovery of plutonium from calcium fluoride reduction slag

    Christensen, D.C.

    A pyrochemical method of recovering finely dispersed plutonium metal from calcium fluoride reduction slag is claimed. The plutonium-bearing slag is crushed and melted in the presence of at least an equimolar amount of calcium chloride and a few percent metallic calcium. The calcium chloride reduces the melting point and thereby decreases the viscosity of the molten mixture. The calcium reduces any oxidized plutonium in the mixture and also causes the dispersed plutonium metal to coalesce and settle out as a separate metallic phase at the bottom of the reaction vessel. Upon cooling the mixture to room temperature, the solid plutonium can be cleanly separated from the overlying solid slag, with an average recovery yield on the order of 96 percent.

  3. Synthesis and Characteristics of Anorthite Ceramics from Steelmaking Slag

    Li, Bowen; He, Mingsheng; Hwang, Jiann-Yang; Gan, Wangui

    Steelmaking slag is an alkaline solid waste consisting mainly oxides of calcium, iron, silicon, magnesium, and aluminum. Its large quantity and chemical property makes it challenging for recycling the material in various industrial applications. In this study, hot-poured steelmaking slag was used to prepare ceramics. After mixing with kaolin and quartz, ceramic products were synthesized via sintering. The appropriate sintering temperature is 1200°C. XRD analysis showed the major mineral phases were anorthite and pyroxene. SEM images showed that the new crystal particles were uniformly formed and distributed. Reaction mechanisms were discussed.

  4. Modeling the service life of slag concrete exposed to chlorides

    O.A. Hodhod


    A partial replacement of OPC with 50% WCS in OPC paste mixes resulted in an increase in the amount of calcium silicate hydrate (CSH by 57%, a decrease in the amount of calcium hydroxide (CH by 66%, and a decrease in the amount of capillary pores by 57%, compared to those in the pure OPC matrix. In addition, the research results demonstrate that increasing Cs from 1% to 5% resulted in dramatically decreasing the service life of OPC/slag concrete, where the amount of decreasing reaches about 71%. Also, the service life of concrete increases with increasing slag content.

  5. Ankeny - Yellow Flag Iris Control

    US Fish and Wildlife Service, Department of the Interior — This project aims to inventory and map all existing stands of yellow flag iris within wetland habitats at Ankeny NWR, treat them with herbicide in late spring and...

  6. Steelmaking slag beneficiation by magnetic separator and impacts on sinter quality

    Bölükbaşı Ö.S.


    Full Text Available Basic oxygen furnaces (BOF slag is the main problem at all iron and steel factories. About more than 6 million tons/year of BOF slag has been accumulated from the waste stockyards in Turkey. Dumps slags can be revaluated by a processing technology which makes it possible to obtain products that meet the requirements of sintering and blast furnace production. The slags with particle size of -10 mm were enriched by the magnetic separator resulting and increase in Fe grade from 18% to 33%. The use of BOF slag in sinter blend provided additional Mn, CaO, MgO and introduced a good solution to environmental problems.

  7. Characterization of ancient Indian iron and entrapped slag inclusions using electron, photon and nuclear microprobes

    P Dillmann; R Balasubramaniam


    Compositional and structural information were obtained from an ancient 1600-year old Indian iron using microprobe techniques (EDS, XRD and PIXE). Several different local locations in the iron matrix and in the entrapped slag inclusions were analyzed. The P content of the metallic iron matrix was very heterogeneous. Lower P contents were observed in the regions near slag inclusions. This was correlated to the dephosphorization capacity of the slag. The crystallized phases identified in the slag inclusions were wüstite and fayalite. The compositions of the slag inclusions were relatively homogeneous.

  8. Future Resources for Eco-building Materials: I.Metallurgical Slag

    XU Delong; LI Hui


    In order to make an effectivily recycle use of iron and steel slags that are main industrial wastes generated in Chinese metallurgical industry,the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed,such as preparing cement-steel slag blended cement with steel slag after metal recovery,using the fine powder of blast furnace slag (BFS)for manufacturing slag cement and high performance concrete.A further research on using these available resources more efficiently were discussed.

  9. Blind Inlet as a Possible Technology for the Remediation of Phosphorus from Surface Runoff

    Sturmlechner, M.; Wu, X.; Livingston, S.; Klik, A.; Huang, C. H.


    Phosphorus (P) is an essential element for plant life, but too much P in runoff water can cause eutrophication and harmful algal blooms. Hence, mitigation of agricultural P losses into the water cycle is a very important issue. In-stream P treatment is difficult to implement because the large amount of storm runoff needs to be treated in short durations. In this research, we evaluated the potential to use blind inlet as an in-field P treatment technology. A box system was built to simulate hydrological and chemical processes occurring in a blind inlet. Current blind inlets, which are already installed in the field, use a bed of limestone with a sand/pea gravel layer on the top. In this study, steel slags has been tested, which has a very high P sorption potential, as the filter media through a series of adsorption and desorption experiments. The P mass balance results are compared with the limestone material used in current blind inlet construction. The total mass of P which was absorbed by the limestone was 14 % of the P input into the system whereas 26 % P was absorbed by the steel slags. Therefore the steel slags show potential to sequester dissolved P. Additional research is on-going to come up with a design criteria for field implementation.

  10. In situ observation of the role of alumina particles on the crystallization behavior of slags

    Orrling, C.


    The confocal laser scanning microscope (CLSM) allows crystallization behavior in liquid slags to he observed in situ at high temperatures. Slags in the lime-silica-alumina-magnesia system are easily tinder cooled and it is possible to construct time temperature transformation (TTT) diagrams for this system. The presence of solid alumina particles its these liquid slags was studied to determine if these particles act as heterogeneous nucleation sites that cause she precipitation of solid material within slags. The introduction of alumina particles reduced the incubation time for the onset of crystallization and increased the temperature at which crystallization was observed in the slags to close to the liquidus temperature for the slag. Crystal growth rates are in a good agreement with Ivantsov's solution of the problem of diffusion controlled dendritic growth. Alumina appears to be a potent nucleating agent in the slag systems that were studied. (author)

  11. Replacement of Natural Fine Aggregate With Air Cooled Blast Furnace Slag An Industrial By Product

    Dr. B. Krishna Rao


    Full Text Available The aim of the investigation is to replace natural fine aggregatewith Air Cooled Blast Furnace Slag in OPC concrete. At present, nearly million tons of slag is being produced in the steel plants, in India. The generation of slag would be dual problem in disposal difficulty and environmental pollution. Some strategies should be used to utilize the slag effectively. Considering physical properties of metallurgical slags and a series of possibilities for their use in the field of civil constructions, this report demonstrates the possibilities of using air cooled blast furnace slag as partial replacement of sand in concrete. A total of five concrete mixes, containing 0%, 12.5%, 25%, 37.5% and 50% partial replacement of regular sand with air cooled blast furnace slag are investigated in the laboratory. These mixes were tested to determine axial compressive strength, split tensile strength, and flexural strength for 7days, 28days, 56days and 90days.

  12. Petrochemistry of coal ash slags. I. Formation of melilite and a high temperature glass from a calcium-rich, silica-deficient slag

    Schobert, H.H.; Barbie, D.L.; Christensen, O.D.; Kerner, F.R.


    Pilot plant studies are being conducted of a fixed-bed slagging coal gasification process. Lignite from the Indianhead mine is reacted with steam and oxygen in a gasifier at hearth zone temperatures over 1650/sup 0/C. Slag samples were subjected to chemical and petrographic analysis. Layers of layered slag modules were analyzed; the inner layers contain abundant melilite while the outer core is a glass. Results show that the characteristics of the coal ash slag can be affected by temperature fluctuations in the gasifier hearth, and that chemical, flow, and heat transfer behavior are all susceptible to change as a result. 8 figs., 3 tables. (DLC)

  13. Responses of Legumes to Phosphorus Deficiency


    Phosphorus deficiency is a universal problem in most world soils. Furthermore, of all nutrients, shortage of phosphorus has the biggest impact on legumes, therefore, lots of studies were carried out for identifying responses of legumes to shortage of phosphorus. They concluded that to maintain improved growth under phosphorus deficiency conditions plants develop two major mechanisms: (i) Phosphorus acquisition (root morphology, root exudation and phosphorus uptake mechanisms), (ii) Phosphorus utilization (internal mechanisms associated with better use of absorbed phosphorus at cellular level). The aim of this brief review is to elucidate root morphological changes and rhizophere acidification to phosphorus deficiency.

  14. Characterization and sonochemical synthesis of black phosphorus from red phosphorus

    Aldave, Sandra H.; Yogeesh, Maruthi N.; Zhu, Weinan; Kim, Joonseok; Sonde, Sushant S.; Nayak, Avinash P.; Akinwande, Deji


    Phosphorene is a new two-dimensional material which is commonly prepared by exfoliation from black phosphorus bulk crystals that historically have been synthesized from white phosphorus under high-pressure conditions. The few layers of phosphorene have a direct band gap in the range of 0.3-2 eV and high mobility at room temperature comparable to epitaxial graphene. These characteristics can be used for the design of high speed digital circuits, radio frequency circuits, flexible and printed systems, and optoelectronic devices. In this work, we synthesized black phosphorus from red phosphorus, which is a safer solid precursor, using sonochemistry. Furthermore, via a variety of microscopy and spectroscopy techniques, we report characterization results of the sonochemically synthesized black phosphorus in addition to the commercial black phosphorus. Finally, we describe the air stability of black phosphors and the crystalline structure of the synthesized material. This is the first result of sonochemical or solution-based synthesis of black phosphorus based on readily available low-cost red phosphorus. This solution-based synthesis of black phosphorus is suitable for printable applications of nanomaterial.


    王保栋; 战闰; 徐明德


    The vertical fluxes and molar ratios of carbon, nitrogen and phosphorus of suspended particulate matter in the Yellow Sea were studied based on the analysis of suspended particulate matter, sediments and sinking particles obtained by use of moored sediment traps. The POC:PON ratios indicate that most of the particulate organic matter in the Yellow Sea water column comes from marine life rather than the continent. The vertical fluxes of SPM, POC, PON and POP in the Yellow Sea are much higher than those in other seas over the world, and present a typical pattern in shallow epicontinental seas. The estimated residence time of the bioactive elements showed that the speed of the biogeochemical process of materials in the Yellow Sea is much shorter than that in the open ocean as there was high primary productivity in this region.

  16. Aluminium salt slag characterization and utilization--a review.

    Tsakiridis, P E


    Aluminium salt slag (also known as aluminium salt cake), which is produced by the secondary aluminium industry, is formed during aluminium scrap/dross melting and contains 15-30% aluminium oxide, 30-55% sodium chloride, 15-30% potassium chloride, 5-7% metallic aluminium and impurities (carbides, nitrides, sulphides and phosphides). Depending on the raw mix the amount of salt slag produced per tonne of secondary aluminium ranges from 200 to 500 kg. As salt slag has been classified as toxic and hazardous waste, it should be managed in compliance with the current legislation. Its landfill disposal is forbidden in most of the European countries and it should be recycled and processed in a proper way by taking the environmental impact into consideration. This paper presents a review of the aluminium salt slag chemical and mineralogical characteristics, as well as various processes for metal recovery, recycling of sodium and potassium chlorides content back to the smelting process and preparation of value added products from the final non metallic residue.


    Tatyana Aleksandrova


    Full Text Available The article presents the results of investigation focused on the utilization of ash and slag wastes (ASW in Russia including investigation of chemical and physical properties of ASW and processing products. Many factors influence the technological properties of ash and slag materials: naturals, processes and environments. The integrated treatment of ash and slag wastes of both stored and re-formed types will allow obtaining the following commercial products: coal concentrate, iron concentrate, aluminosilicate cenospheres, aluminosilicate product. In this study we have analyzed the methods for separation of ASW iron-containing part using the different types of the magnetic separation from the ash and slag material from one of the combined heat and power plant (CHPP in the Russian Far East Federal District. The greatest interest is the dry magnetic separation with travelling electromagnetic field. The subject of research was a sample taken from one of ash dump of CHPP in the Far East. In the study iron concentrate containing Fetotal = 64% was obtained recovery 68% in the low intensity (up to 5 kOe travelling magnetic field.

  18. The Interfacial Transition Zone in Alkali-Activated Slag Mortars

    Rackel eSan Nicolas


    Full Text Available The interfacial transition zone (ITZ is known to strongly influence the mechanical and transport properties of mortars and concretes. This paper studies the ITZ between siliceous (quartz aggregates and alkali activated slag binders in the context of mortar specimens. Backscattered electron images (BSE generated in an environmental scanning electron microscope (ESEM are used to identify unreacted binder components, reaction products and porosity in the zone surrounding aggregate particles, by composition and density contrast. X-ray mapping is used to exclude the regions corresponding to the aggregates from the BSE image of the ITZ, thus enabling analysis of only the binder phases, which are segmented into binary images by grey level discrimination. A distinct yet dense ITZ region is present in the alkali-activated slag mortars, containing a reduced content of unreacted slag particles compared to the bulk binder. The elemental analysis of this region shows that it contains a (C,N-A-S-H gel which seems to have a higher content of Na (potentially deposited through desiccation of the pore solution and a lower content of Ca than the bulk inner and outer products forming in the main binding region. These differences are potentially important in terms of long-term concrete performance, as the absence of a highly porous interfacial transition zone region is expected to provide a positive influence on the mechanical and transport properties of alkali-activated slag concretes.

  19. Micronutrient availability from steel slag amendment in peatmoss substrates

    The objective of this research was to determine the suitability of a steel slag product for supplying micronutrients to container-grown floriculture crops. Geranium (Pelargonium xhortorum 'Maverick Red') and tomato (Solanum lycopersicon 'Megabite') were grown in 11.4 cm containers with a substrate ...

  20. Slagging in a pulverised-coal-fired boiler

    Devir, G.P.; Pohl, J.H.; Creelman, R.A. [University of Queensland, St. Lucia, Qld. (Australia). Dept. of Chemical Engineering


    This paper describes a technique to evaluate the severity of slagging of a coal in a pulverised-coal-fired boiler. There are few data in the literature on the nature of in-situ boiler slags, their rate of growth and/or their strength properties relevant to sootblowing. The latter is thought to be of more concern to boiler operators and gives rise to the significance of selecting suitable strength tests. As well as standardised methods for characterising pulverised coal performance in a boiler, several novel and less popular techniques are discussed in detail. A suite of three sub-bituminous coals from the Callide Coalfields, Biloela (600 km north of Brisbane), has been selected for slagging tests in the 350 MW{sub e} units of Callide 'B' power station. Disposable air-cooled mild steel slagging probes have been constructed to simulate the conditions for deposit formation in the boiler region. To date, tests for one of these coals has been completed and preliminary results are presented. Once testing for the remaining coals has been completed, it is anticipated that the differences exhibited in deposit growth and strength may be correlated with typical variations in physical and chemical properties of the pulverised coal.

  1. 基于低污染的宁夏引黄灌区13种种植模式氮磷平衡分析%Analysis of equilibrium between nitrogen and phosphorus in thirteen planting patterns in the area irrigated with Yellow River water in Ningxia based on low pollution

    刘根红; 许强; 康建宏; 吴宏亮; 赵亚慧


    针对宁夏引黄灌区农业生产中大量施用化肥对环境及农业退水污染严重的实际,本试验以宁夏引黄灌区现有小麦/玉米为对照,通过选择冬小麦复种水稻及组配麦后复种(蔬菜、青贮玉米、油葵等)等13种种植模式,研究不同模式在作物不同生长时期内土壤氮磷运移规律以及综合效益,选择利于农业清洁生产的种植模式.结果表明:相对于单作,间套作由于增加了田面作物的覆盖时间,对降低土壤氮磷残留量效果明显;以土壤氮磷为主要衡量指标,结合经济效益,筛选出了适合于该灌区大面积种植,经济效益较高的四种低污染模式为:冬小麦复种水稻、春小麦复种芹菜、冬小麦复种青贮、冬小麦复种油葵,四种模式中尤以冬小麦复种水稻效益最明显,土壤中氮流失总量比对照低56.2%,磷流失总量比对照低28.6%.%In the face of the serious pollution caused by fertilizer application to environment and agricultural recession water, a test was conducted to explore soil nitrogen and phosphorus equilibrium regulation and economic valuation for thirteen planting patterns selected from traditional patterns such as planting rice after winter wheat harvest etc and assembled patterns such as cultivating vegetables and silage corn and oil sunflower and so on during different crops growing seasons compared with spring wheat intercropped with corn for cleaning agricultural production. The outcome showed as follows: Intercropping patterns were beneficial to reducing soil nitrogen and phosphorus amounts on account of prolonging crops covering time during crops growing season, and four cropping patterns of planting rice after winter wheat harvest, planting celery after winter wheat harvest, planting silage after winter wheat harvest and planting oil sunflower after winter wheat harvest were selected based on economic efficiency and less soil nitrogen and phosphorus amounts. The pattern of

  2. Sustainable Phosphorus Measures: Strategies and Technologies for Achieving Phosphorus Security

    Stuart White


    Full Text Available Phosphorus underpins the world’s food systems by ensuring soil fertility, maximising crop yields, supporting farmer livelihoods and ultimately food security. Yet increasing concerns around long-term availability and accessibility of the world’s main source of phosphorus—phosphate rock, means there is a need to investigate sustainable measures to buffer the world’s food systems against the long and short-term impacts of global phosphorus scarcity. While the timeline of phosphorus scarcity is contested, there is consensus that more efficient use and recycling of phosphorus is required. While the agricultural sector will be crucial in achieving this, sustainable phosphorus measures in sectors upstream and downstream of agriculture from mine to fork will also need to be addressed. This paper presents a comprehensive classification of all potential phosphorus supply- and demand-side measures to meet long-term phosphorus needs for food production. Examples range from increasing efficiency in the agricultural and mining sector, to technologies for recovering phosphorus from urine and food waste. Such measures are often undertaken in isolation from one another rather than linked in an integrated strategy. This integrated approach will enable scientists and policy-makers to take a systematic approach when identifying potential sustainable phosphorus measures. If a systematic approach is not taken, there is a risk of inappropriate investment in research and implementation of technologies and that will not ultimately ensure sufficient access to phosphorus to produce food in the future. The paper concludes by introducing a framework to assess and compare sustainable phosphorus measures and to determine the least cost options in a given context.

  3. Smog Yellows Taj Mahal


    Built as a monument to the favorite wife of the Mughal Emperor Shah Jahan, the Taj Mahal has watched over the city of Agra, India, since the mid-seventeenth century with its pillars of gleaming white marble. By the spring of 2007, however, one of the world's most visited landmarks was turning yellow, and a panel of India's parliament had little trouble identifying the culprit: pollution. The panel blamed particles of soot and dirt suspended high in the atmosphere for the Taj Mahal's dinginess. The Taj Mahal's home, Agra, sits not far from the base of the Himalaya, and smog regularly collects along the southern side of the mountain range. On May 16, 2007, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image of the area around Agra, India. The closeup image shows the immediate vicinity of the Taj Majal. The larger image shows the surrounding area. In both pictures, dingy, gray-beige haze obscures the satellite's view of the land surface. India had tried to minimize the adverse impact of air pollution on the famous landmark. According to the BBC, in the late 1990s, India's Supreme Court ordered the closure of thousands of iron foundries and kilns that had belched smoke near the monument. Many of the 3 million tourists who visited the Taj Majal each year approached the monument on horse-drawn carriages or battery-operated buses as fossil-fuel-powered vehicles could not drive within 2 kilometers (1.5 miles). Since those efforts have failed to save the Taj Majal's complexion, Indian officials have considered applying a cleansing mud pack to the monument's surface to draw out the dirt. As India industrializes, smog results, and the Taj Mahal's gleaming whiteness is only one casualty. Pollution has been blamed for a decrease in Indian rice harvests, which had soared during the 'Green Revolution' of the 1960s and 1970s. Haze and dust also appear to bring on the region's monsoon rains earlier than normal.

  4. [Effects of polyunsaturated fatty acids on Krebs cycle in the rat kidney in chronic phosphorus intoxication].

    Kulkybaev, G A; Merkusheva, N V


    The investigation of Krebs cycle state in kidney homogenates of August rats subjected to oral intoxication with oil solution of yellow phosphorus in a dose of 0.3 mg/kg, has shown that under conditions of balanced nutrition the activity of NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase and accumulation of the substrate fund of the cycle decreased 3.5-fold as compared to the control. The addition of polyunsaturated fatty acids to the ration produced a positive effect on Krebs cycle state: dehydrogenase activity was not significantly changed, accumulation of Krebs cycle substrate was two-fold lower. However, this ration did not completely abolish the toxic action of yellow phosphorus on Krebs cycle.

  5. Corrosion Behavior of Ceramic Cup of Blast Furnace Hearth by Liquid Iron and Slag

    Li, Yanglong; Cheng, Shusen; Wang, Zhifeng


    Three kinds of sample bricks of ceramic cups for blast furnace hearth were studied by dynamic corrosion tests based on different corrosion systems, i.e., liquid iron system, liquid slag system and liquid iron-slag system. Considering the influence of temperature and sample rotational speed, the corrosion profiles and mass loss of the samples were analyzed. In addition, the microstructure of the corroded samples was observed by optical microscope (OM) and scanning electron microscope (SEM). It was found that the corrosion profiles could be divided into iron corrosion region, slag corrosion region and iron-slag corrosion region via corrosion degree after iron-slag corrosion experiment. The most serious corrosion occurred in iron-slag corrosion region. This is due to Marangoni effect, which promotes a slag film formed between liquid iron and ceramic cup and results in local corrosion. The corrosion of the samples deepened with increasing temperature of liquid iron and slag from 1,623 K to 1,823 K. The variation of slag composition had greater influence on the erosion degree than that of rotational speed in this experiment. Taking these results into account the ceramic cup composition should be close to slag composition to decrease the chemical reaction. A microporous and strong material should be applied for ceramic cup.

  6. Micronutrientes in the sugarcane irrigated: correction of the soil with siderurgical slag

    Napoleão Esberard de Macêdo Beltrão


    Full Text Available The beneficial effects of manuring with siderurgical slag has been researched in several species, mainly among grassy such as sugarcane (Saccharum officinarum L.. The experiment was installed in the field, using one of the most representative sugarcane soils of Alagoas State, was cultivated in Dystrophic AGREY ARGISSOIL. The siderurgical slag source was containing 11% of soluble SiO2. The objective this research was quantify foliate micronutrients in the sugarcane and pH of soil due siderurgical slag application submitted the different irrigation water in São Sebastião city. For such the design was band of randomizered blocks, with five doses of siderurgical slags (band and five water (sub band and four repetitions. The analyzed variables were the micronutrients concentrations (Zn, Cu, Fe and Mn in the leaf. The slag application increased the concentrations significantly foliate of Zn while concentrations of Cu and Fe decreased. The foliate concentration of Mn, in the interaction of slag and irrigation water, it decreased in the cane plants and first it would beat, when the factor was slag inside of irrigation water however, when the factor was sheets inside of slag, there was increase of the concentration this element us of the cycles. The foliate concentration of Mn, due the interactive effect of slag and irrigation water, decreased in the first cut. However, when the factor was irrigation water inside of slag, there was increase of concentration of this in the two cycles.

  7. Diffusion of hexavalent chromium in chromium-containing slag as affected by microbial detoxification.

    Wang, Yunyan; Yang, Zhihui; Chai, Liyuan; Zhao, Kun


    An electrochemical method was used to determine the diffusion coefficient of chromium(VI) in chromium-containing slag. A slag plate was prepared from the original slag or the detoxified slag by Achromobacter sp. CH-1. The results revealed that the apparent diffusion coefficient of Cr(VI) was 4.4 x 10(-9)m(2)s(-1) in original slag and 2.62 x 10(-8)m(2)s(-1) in detoxified slag. The results implied that detoxification of chromium-containing slag by Achromobacter sp. CH-1 could enhance Cr(VI) release. Meanwhile, the results of laboratory experiment showed that the residual total Cr(VI) in slag decreased from an initial value of 6.8 mg g(-1) to 0.338 mg g(-1) at the end of the detoxification process. The Cr(VI) released from slag was also reduced by Achromobacter sp. CH-1 strain since water soluble Cr(VI) in the leachate was not detected after 4 days. Therefore, Achromobacter sp. CH-1 has potential application for the bio-detoxification of chromium-containing slag.

  8. An alternative approach for reusing slags from a plasma vitrification process

    Kuo, Y.-M. [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, 89, Wenhwa 1st St., Rende Shiang, Tainan County 71703, Taiwan (China)], E-mail:; Tseng, H.-J. [Department of Foundry Engineering, National Tainan Industrial Vocational High School, Tainan 71075, Taiwan (China); Chang, J.-E. [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Wang, J.-W.; Wang, C.-T. [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, 89, Wenhwa 1st St., Rende Shiang, Tainan County 71703, Taiwan (China); Chen, H.-T. [Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China)


    Vitrification is widely applied to transform hazardous materials into inert slags. Raising the value of the recycled slag is an important issue from an economic point of view. In this study, an alternative approach for mixing a plasma slag with unsaturated polyester resin for making the dough-like molding composites is proposed. Physical properties, including ultimate tensile strength, Rockwell hardness, and the elongation at break, were measured to evaluate the characteristics of the composites. A scanning electron microscope and an X-ray diffractometer were used to examine the micro characteristics of the specimens. The chemical stability of the composites was estimated using the toxicity characteristic leaching procedure and a hot water bathing process. In an optimal slag loading (mass ratio of slag to unsaturated polyester resin) ranged from 0.1 to 0.2, the slag powder improved the physical properties of the composites. With an increased slag loading, excess slag powder weakened the structure of the resin, reducing the ultimate tensile strength and Rockwell hardness. The acid and water bathing tests indicated that the resin is decomposed in a hot environment. However, the slag was not destructed nor were the hazardous metals leached out. The results show that the molding method is an effective technology to recycle the slag.

  9. Local corrosion of magnesia-chrome refractory at slag-metal interface; Yoyu slag metal kaimen ni okeru magnesia / chrom shitsu taikabutsu no kyokubu sonsho

    Tao, Z.; Mukai, K.; Ogata, M. [Kyushu Inst. of Tech., Kitakyushu, Fukuoka (Japan)


    The corrosion mode of refractory depending on the chemical dissolution of molten slag-metal, a component of refractory is classified mainly into the corrosion of inner slag phase body and inner metal phase body, and local corrosion at slag surface and slag-metal interface, and local corrosion at the interface of different type of refractories. Among them, local corrosion occurring at the slag-metal interface is a serious problem that effects the life of refractory, and these recent years research regarding the prevention of this type of local corrosion has been closed up. So far, number of researches regarding the local corrosion of solid oxides at slag-metal interface has been carried out. However, these are all based on close single component and research regarding the practical oxides with multiple components and multiporous characteristic has not been carried out. In this research, practical magnesia-chrome refractory (CaO-SiO2-Al203-FetO) slag-metal system is described and revelation of local corrosion phenomena at slag-metal interface was studied. 17 refs., 14 figs., 2 tabs.

  10. 饲粮非植酸磷水平对39~46周龄黄羽肉种母鸡繁殖性能、胫骨指标和血浆生化指标的影响%Effect of Dietary Non-Phytate Phosphorus Level on Reproduction Performance, Tibial Indexes and Plasma Biochemical Indexes of Yellow-Feathered Broiler Breeders Aged from 39 to 46 Weeks

    蒋守群; 蒋宗勇; 郑春田; 丁发源; 阮栋


    本试验旨在研究不同非植酸磷( NPP)水平对39~46周龄黄羽肉鸡父母代种鸡繁殖性能、胫骨指标和血浆生化指标的影响,探讨该阶段适宜磷供给量。试验选用39周龄岭南黄羽肉鸡父母代种母鸡810只,根据体重和产蛋率分为5个组,每组6个重复,每重复27只鸡。组1为对照组,饲喂玉米-豆粕型基础饲粮( NPP水平为0.30%),组2、3、4和5饲粮分别在基础饲粮中添加不同水平的磷酸氢钙,使饲粮NPP水平分别为0.35%、0.40%、0.45%和0.50%,其他营养成分各组基本一致。试鸡限饲122 g/(只·d),自由饮水。试验期8周。结果表明:1)试验期内, NPP水平未显著影响试鸡平均日增重、平均日产蛋量、料蛋比、平均蛋重和破蛋率(P>0.05),显著影响了产蛋率和不合格蛋率(P0.05)。4)饲粮 NPP 水平显著增加了试鸡脱脂胫骨粗灰分中钙、磷含量(P0.05), had significant effects on laying rate and unqualified egg rate ( P0.05) . 4) The contents of calcium and phosphorus in dry defatted tibi-al ash were significantly increased by dietary NPP supplementation (P<0.05). 5) The contents in plasma of parathyroid hormone was significantly higher in birds fed diets containing 0.40% and 0.45% NPP than in those of 0.30% and 0.35% NPP (P<0.05) and calcitonin was higher in birds fed 0.50% NPP than all other NPP levels ( P<0.05) . The results indicate that the optimal dietary NPP level for yellow-feathered broiler breeders aged from 39 to 46 weeks is 0.40% to 0.45%, equivalent to 0.488 to 0.549 g/d on the basis of calculated by feed intake.

  11. Effects of Design/Operating Parameters and Physical Properties on Slag Thickness and Heat Transfer during Coal Gasification

    Insoo Ye


    Full Text Available The behaviors of the slag layers formed by the deposition of molten ash onto the wall are important for the operation of entrained coal gasifiers. In this study, the effects of design/operation parameters and slag properties on the slag behaviors were assessed in a commercial coal gasifier using numerical modeling. The parameters influenced the slag behaviors through mechanisms interrelated to the heat transfer, temperature, velocity, and viscosity of the slag layers. The velocity profile of the liquid slag was less sensitive to the variations in the parameters. Therefore, the change in the liquid slag thickness was typically smaller than that of the solid slag. The gas temperature was the most influential factor, because of its dominant effect on the radiative heat transfer to the slag layer. The solid slag thickness exponentially increased with higher gas temperatures. The influence of the ash deposition rate was diminished by the high-velocity region developed near the liquid slag surface. The slag viscosity significantly influenced the solid slag thickness through the corresponding changes in the critical temperature and the temperature gradient (heat flux. For the bottom cone of the gasifier, steeper angles were favorable in reducing the thickness of the slag layers.

  12. Effect of Substituting Yellow Maize for Sorghum on Broiler Performance

    Mohammed A. Ahmed


    Full Text Available An experiment was conducted to study the nutritional value of yellow maize when it substitutes sorghum grain as source of energy at levels 0, 25, 50, 75 and 100% in broiler rations. One hundred and forty unsexed one day old (Ross broiler chicks were randomly assigned to five approximately isocaloric and isonitrogenous diets labeled as follows: Diet (S0 containing sorghum 100% (control, 60% of the diet, diet (S1 75% sorghum 25% maize, diet (S2 50% sorghum 50% maize, diet (S3 25% sorghum 75% maize and diet (S4 maize (100% (without sorghum. Each treatment had four replicates with 7 birds/replicate. The experiment lasted for 6 weeks. Feed intake and body weight gain had been recorded weekly. The results showed significant increase (P 0.05 effect on cold carcass dressing percentage, liver and abdominal fat weights, serum cholesterol, serum calcium and inorganic phosphorus levels. The cost of production decreased by increasing level of maize.

  13. Virtual phosphorus ore requirement of Japanese economy.

    Matsubae, Kazuyo; Kajiyama, Jun; Hiraki, Takehito; Nagasaka, Tetsuya


    Phosphorus is indispensable for agricultural production. Hence, the consumption of imported food indirectly implies the import of phosphorus resources. The global consumption of agricultural products depends on a small number of ore-producing countries. For sustainable management of phosphorus resources, the global supply and demand network should be clarified. In this study, we propose the virtual phosphorus ore requirement as a new indicator of the direct and indirect phosphorus requirements for our society. The virtual phosphorus ore requirement indicates the direct and indirect demands for phosphorus ore transformed into agricultural products and fertilizer. In this study, the virtual phosphorus ore requirement was evaluated for the Japanese economy in 2005. Importantly, the results show that our society requires twice as much phosphorus ore as the domestic demand for fertilizer production. The phosphorus contained in "eaten" agricultural products was only 12% of virtual phosphorus ore requirement.

  14. Recycling of industrial waste and performance of steel slag green concrete

    LI Yun-feng; YAO Yan; WANG Ling


    Workability and mechanical properties of steel slag green concrete with different types of steel slag and different dosages of admixtures were investigated. The effectiveness of steel slag powder on suppressing alkali aggregate reaction (AAR) expansion was assessed using the method of ASTM C441 and accelerated test method. Experimental results show that mechanical properties can be improved further due to the synergistic effect and mutual activation when compound mineral admixtures with steel slag powder and blast-furnace slag powder are mixed into concrete, in addition, about 50% decrease in expansion rate of mortar bars with mineral admixtures can be achieved in AAR tests. Mineral admixtures with steel slag powder as partial replacement for Portland cement in concrete is an effective means for controlling expansion due to AAR.

  15. The effect of primary copper slag cooling rate on the copper valorization in the flotation process

    Aleksandar Mihajlović


    Full Text Available Technological procedure of slow cooling slag from primary copper production is applied in the purpose of copper recovery in the level of 98.5% to blister. This technological procedure is divided into two phases, first slow cooling of slag on the air for 24 hours, and then accelerated cooling with water for 48 hours. Within the research following methods were used: calculation of nonstationary slag cooling, verification of the calculation using computer simulation of slag cooling in the software package COMSOL Multiphysics and experimental verification of simulation results. After testing of the experimentally gained samples of slowly cooled slag it was found that this technological procedure gives the best results in promoting growth or coagulation of dispersed particles of copper sulfide and copper in the slag, thereby increasing the utilization of the flotation process with a decrease of copper losses through very fine particles.

  16. The estimation of the reaction stimulators influence into the extraction slag conditions

    A. W. Bydałek


    Full Text Available Slag stimulators was analysed used the DTA methods. In the paper a method of determining the reduction capability of slag solutions wasused. The analysis of slag stimulators concertinaing of the chloride and fluoride compositions are showed. There are the oxides complexesused in to the slag composition for the purpose to establish two indicators in reduction processes: EW - indicator showing the direction and intensity of reaction in to the slag composition, and r - indicator of the rate of coal consumption. There are possible and purposeful the construction optimization programme engaging all of the phisics chemical influence the slags in processes of melting metals alloys. The proposed results, ranges of areas on graphs of phase equilibria's, demonstrative on the optimum values, will be verified in laboratory conditions and industrial. The initiation the new data the gathered base will be built in system of open base enabling.


    Z.Z. Guo; T.P. Lou; L. Zhang; L.N. Zhang; Z.T. Sui


    The effects of transformation of slag composition and additive agents on the morphology, the crystal in the Ti-bearing blast furnace slags were investigated. As the morphology of perovskite is dispersed in molten slags, the crystal growth mechanism of the melting of fine dendrites and the coarsening of large grains exist throughout the solidification of molten slags. With the increase of CaO and Fe2O3 content, VF of perovskite obviously increases. However, high basicity leads to the viscosity of slag, which results in the reduction of the average equivalent diameter (AED). The experimental results showed that the presence of the additives CaF2 and MnO efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promoted its growth.

  18. Corrosion behavior of steel in concrete made with slag-blended cement

    Dehghanian, C. [Univ. of Technology, Isfahan (Iran, Islamic Republic of). Dept. of Chemical Engineering


    Concretes formulated with slag as a partial replacement for cement were used to evaluate the corrosion behavior of steel embedded in concrete, resistivity, and the compressive strength of the concrete. Corrosion rates and pitting corrosion of steel in concrete with up to 30% slag and exposed to sodium chloride (NaCl) solutions decreased. Slag-blended cement concrete increased concrete resistivity. A water-to-cement ratio <0.55 and submersion in water for a period of 18 days gave the best chloride (Cl{sup {minus}}) diffusion resistance from the external salt solutions. Compressive strength of the concrete decreased with addition of slag in the early ages of the concrete. After 5 months of age, compressive strength of the concrete increased with addition of slag. This trend continued with up to 30% slag addition.

  19. Modification of steelmaking slag by additions of salts from aluminum production

    Walker, David C.

    The most common slag fluidizer in steelmaking is fluorspar, a mineral primarily composed of CaF2. Because of increasing consumption and decreasing availability of cheap fluorspar, steelmakers are seeking alternative means of achieving slag fluidity. One possible alternative to fluorspar is spent salt from secondary aluminum production. This salt is obtained from the used flux in remelting aluminum scrap and dross. This material is widely available and considered toxic (meaning that use in steelmaking helps to reduce environmental impacts from disposal). This project is an investigation of spent salt as a replacement for fluorspar in slag-fluidizing applications by viscosity measurements and weight loss measurements at high temperatures (to evaluate the amounts of gases are formed). In addition, characterization of raw materials and melted slags by XRD, chemical analysis, and EPMA have been undertaken. The spent salt addition has a positive effect on slag fluidity, and shows promise for use in slags.

  20. Yellow River, Cradle of China


    THE Yellow River is the Mother River of China. In the hearts of the Chinese people, it is not just an ancient river measuring 4,845 kilometers long that passes through nine provinces and regions, but also a symbol. The poets say that the waterway is the image of ancient China. Thephilosophers say the river is the shadow of a dragon. The river

  1. Optimisation of the slag mode in the ladle during the steel processing of secondary metallurgy

    Socha, Ladislav; Bažan, Jiří; Gryc, Karel; Morávka, Jan; Styrnal, Petr; Pilka, Václav; Piegza, Zbygněv


    Optimisation of the slag mode in the ladle with the help of briquetted fluxing agents, based on Al2O3 under various technological conditions is the object of this paper. The aim of the industrial experiments was to assess the possibility of achieving the optimum chemical composition of the slag that would improve the kinetic conditions of the refining ladle slag during the treatment in secondary metallurgy units. Industrial experiments were focused on comparing the influences of d...

  2. Effects of slag-based silicon fertilizer on rice growth and brown-spot resistance.

    Dongfeng Ning

    Full Text Available It is well documented that slag-based silicon fertilizers have beneficial effects on the growth and disease resistance of rice. However, their effects vary greatly with sources of slag and are closely related to availability of silicon (Si in these materials. To date, few researches have been done to compare the differences in plant performance and disease resistance between different slag-based silicon fertilizers applied at the same rate of plant-available Si. In the present study both steel and iron slags were chosen to investigate their effects on rice growth and disease resistance under greenhouse conditions. Both scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to examine the effects of slags on ultrastructural changes in leaves of rice naturally infected by Bipolaris oryaze, the causal agent of brown spot. The results showed that both slag-based Si fertilizers tested significantly increased rice growth and yield, but decreased brown spot incidence, with steel slag showing a stronger effect than iron slag. The results of SEM analysis showed that application of slags led to more pronounced cell silicification in rice leaves, more silica cells, and more pronounced and larger papilla as well. The results of TEM analysis showed that mesophyll cells of slag-untreated rice leaf were disorganized, with colonization of the fungus (Bipolaris oryzae, including chloroplast degradation and cell wall alterations. The application of slag maintained mesophyll cells relatively intact and increased the thickness of silicon layer. It can be concluded that applying slag-based fertilizer to Si-deficient paddy soil is necessary for improving both rice productivity and brown spot resistance. The immobile silicon deposited in host cell walls and papillae sites is the first physical barrier for fungal penetration, while the soluble Si in the cytoplasm enhances physiological or induced resistance to fungal colonization.

  3. A prototype industrial sensing system for phosphorus based on micro system technology.

    Bowden, Michaela; Sequeira, Margaret; Krog, Jens Peter; Gravesen, Peter; Diamond, Dermot


    Progress in the development of a miniaturised microfluidic instrument for monitoring phosphorus in natural waters and wastewater is presented. The yellow colorimetric method for phosphate analysis has been transferred to a microfluidic chip configuration This simple method employs one reagent mixed in a 1:1 ratio with a sample to produce a yellow colour absorbing strongly below 400 nm. A stopped flow approach is used which, together with the very rapid kinetics and simple reagent stream, enables a very uncomplicated microfluidic manifold design to be adopted. The working wavelength is 380 nm to coincide with the peak output of a recently developed UV-LED narrow bandwidth light source. The limit of detection for the yellow method is 0.2 ppm with a dynamic linear range from 0-50 ppm possible. The reaction time at room temperature is less than 3 min, which means that up to 20 samples per hour can be analysed.

  4. A novel process for comprehensive utilization of vanadium slag

    Liu, Li-ying; Du, Tao; Tan, Wen-jun; Zhang, Xin-pu; Yang, Fan


    Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas, which cause serious environmental problems. In this study, a new process for the comprehensive utilization of vanadium slag was proposed, wherein zeolite A and a V2O5/TiO2 system were synthesized. The structural properties of the as-synthesized zeolite A and the V2O5/TiO2 system were characterized using various experimental techniques, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and infrared spectroscopy. The results reveal that zeolite A and the V2O5/TiO2 system are successfully obtained with high purity. The results of gas adsorption measurements indicate that the prepared zeolite A exhibits high selectivity for CO2 over N2 and is a candidate material for CO2 capture from flue-gas streams.

  5. Effect of Superfine Slag Powder on HPC Properties


    A superfine slag powder (SP) made from granulated blast furnace slag incorporating activators by using special millingtechnique, was used as supplementary cementitious material in high performance concrete (HPC), replacing part ofthe mass of normal Portland cement. The effects of the SP on the workability, mechanical and crack self-healingproperties of HPC were studied. The hydration process and microstructure characteristics were investigated by X-raydiffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The crack self-healing capacitywas evaluated by Brazilian test. The test results indicate that the SP has especially supplementary effect on waterreducing and excellent property of better control of slump loss. The concrete flowability increases remarkably withthe increase of SP replacement level in the range of 20% to 50%. The compressive and splitting tensile strengthsof HPC containing SP are higher than the corresponding strength of the control concrete at all ages. The crackself-healing ability is highly dependent on SP content of HPC.

  6. Alkali based slagging: a case study from Leigh Creek

    R.A. Creelman; J. Bamberry; L.A. Juniper; C. Ward [University of Western Sydney, Penrith South, NSW (Australia)


    A systematic study was undertaken at NRG Port Augusta Power station in South Australia to determine the cause of ash deposition (slagging) in the boilers. Conventional wisdom suggests that iron in the ash is generally a major player in furnace ash deposition; however, mineralogical and chemical analyses of the deposits showed that the binding phase was plagioclase feldspar, dominated by the sodic feldspar albite. The study resulted in recognition that the cause of the formation of ash deposits in the North Flinders furnaces was the result of the ingestion of sodium and calcium into the melt that bound the deposits. This finding was a breakthrough in understanding the deposition process within these furnaces, and emphasises that not all slagging is iron related and that systematic studies of deposits, coal and ash make fundamental contributions to understanding the ash deposition mechanisms. 9 refs., 5 figs., 2 tabs.

  7. Use of ancient copper slags in Portland cement and alkali activated cement matrices.

    Nazer, Amin; Payá, Jordi; Borrachero, María Victoria; Monzó, José


    Some Chilean copper slag dumps from the nineteenth century still remain, without a proposed use that encourages recycling and reduces environmental impact. In this paper, the copper slag abandoned in landfills is proposed as a new building material. The slags studied were taken from Playa Negra and Púquios dumps, both located in the region of Atacama in northern Chile. Pozzolanic activity in lime and Portland cement systems, as well as the alkali activation in pastes with copper slag cured at different temperatures, was studied. The reactivity of the slag was measured using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), electrical conductivity and pH in aqueous suspension and Fourier Transform Infrared Spectroscopy (FTIR). Furthermore, copper slag-Portland cement mortars with the substitution of 25% (by weight) of cement by copper slag and alkali-activated slag mortars cured at 20 and 65 °C were made, to determine the compressive strength. The results indicate that the ancient copper slags studied have interesting binding properties for the construction sector.

  8. Microscopic Study of Carbon Surfaces Interacting with High Carbon Ferromanganese Slag

    Safarian, Jafar; Kolbeinsen, Leiv


    The interaction of carbon materials with molten slags occurs in many pyro-metallurgical processes. In the production of high carbon ferromanganese in submerged arc furnace, the carbothermic reduction of MnO-containing silicate slags yields the metal product. In order to study the interaction of carbon with MnO-containing slags, sessile drop wettability technique is employed in this study to reduce MnO from a molten slag drop by carbon substrates. The interfacial area on the carbon substrate before and after reaction with slag is studied by scanning electron microscope. It is indicated that no Mn metal particles are found at the interface through the reduction of the MnO slag. Moreover, the reduction of MnO occurs through the contribution of Boudouard reaction and it causes carbon consumption in particular active sites at the interface, which generate carbon degradation and open pore growth at the interface. It is shown that the slag is fragmented to many micro-droplets at the reaction interface, potentially due to the effect on the interfacial energies of a provisional liquid Mn thin film. The rapid reduction of these slag micro-droplets affects the carbon surface with making deep micro-pores. A mechanism for the formation of slag micro-droplets is proposed, which is based on the formation of provisional micro thin films of liquid Mn at the interface.

  9. Environmental impacts of asphalt mixes with electric arc furnace steel slag.

    Milačič, Radmila; Zuliani, Tea; Oblak, Tina; Mladenovič, Ana; Ančar, Janez Šč


    Electric arc furnace (EAF) steel slag can be used as an alternative high-quality material in road construction. Although asphalts with slag aggregates have been recognized as environmentally acceptable, there is a lack of data concerning the potential leaching of toxic Cr(VI) due to the highly alkaline media of EAF slag. Leaching of selected water extractable metals from slag indicated elevated concentrations of total chromium and Cr(VI). To estimate the environmental impacts of asphalt mixes with slag, leachability tests based on diffusion were performed using pure water and salt water as leaching agents. Compact and ground asphalt composites with natural aggregates, and asphalt composites in which the natural aggregates were completely replaced by slag were prepared. The concentrations of total chromium and Cr(VI) were determined in leachates over a time period of 6 mo. After 1 and 6 mo, the concentrations of some other metals were also determined in the leachates. The results indicated that chromium in leachates from asphalt composites with the addition of slag was present almost solely in its hexavalent form. However, the concentrations were very low (below 25 μg L) and did not represent an environmental burden. The leaching of other metals from asphalt composites with the addition of slag was negligible. Therefore, the investigated EAF slag can be considered as environmentally safe substitute for natural aggregates in asphalt mixes.




    Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. Conventional slag removal methods including soot blowers and water lances have great difficulties in removing slags especially from the down stream areas of utility power plant boilers. The detonation wave technique, based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. A slight increase in the boiler efficiency, due to more effective ash/deposit removal and corresponding reduction in plant maintenance downtime and increased heat transfer efficiency, will save millions of dollars in operational costs. Reductions in toxic emissions will also be accomplished due to reduction in coal usage. Detonation waves have been demonstrated experimentally to have exceptionally high shearing capability, important to the task of removing slag and fouling deposits. The experimental results describe the parametric study of the input parameters in removing the different types of slag and operating condition. The experimental results show that both the single and multi shot detonation waves have high potential in effectively removing slag deposit from boiler heat transfer surfaces. The results obtained are encouraging and satisfactory. A good indication has also been obtained from the agreement with the preliminary computational fluid dynamics analysis that the wave impacts are more effective in removing slag deposits from tube bundles rather than single tube. This report presents results obtained in effectively removing three different types of slag (economizer, reheater, and air-heater) t a distance of up to 20 cm from the exit of the detonation tube. The experimental results show that the softer slags can be removed more easily. Also closer the slag to the exit of

  11. A Microstructure Based Strength Model for Slag Blended Concrete with Various Curing Temperatures

    Li-Na Zhang


    Full Text Available Ground granulated blast furnace slag, which is a byproduct obtained during steel manufacture, has been widely used for concrete structures in order to reduce carbon dioxide emissions and improve durability. This paper presents a numerical model to evaluate compressive strength development of slag blended concrete at isothermal curing temperatures and time varying curing temperatures. First, the numerical model starts with a cement-slag blended hydration model which simulates both cement hydration and slag reaction. The accelerations of cement hydration and slag reaction at elevated temperatures are modeled by Arrhenius law. Second, the gel-space ratios of hardening concrete are calculated using reaction degrees of cement and slag. Using a modified Powers’ gel-space ratio strength theory, the strength of slag blended concrete is evaluated considering both strengthening factors and weakening factors involved in strength development process. The proposed model is verified using experimental results of strength development of slag blended concrete with different slag contents and different curing temperatures.

  12. Effects of Carbo-Nitridation Process of Ti-Bearing Blast Furnace Slag on Iron Content

    Shi, Z.; Zhang, X. M.; Xu, Y.

    In order to prepare corrosion-resistant refractory material, experiment chooses Ti-bearing Blast Furnace Slag as raw materials which were treated by the method of carbo-nitridation. Finally, the corrosion resistance properties of the material can be improved by this method. The carbo-nitridation process affects the iron content of the slag in the study, which have a beneficial effect on the synthesis of Ti (C. N). The results indicated that the iron content of the slag significantly increased in process of Ti (C. N) synthesis: and the iron content of slag showed an upward trend with the increase of holding time.

  13. Gasification slag rheology and crystalline phase formation in titanium-calcium-alumina-silica-rich glass

    Brooker, D.D. [Texaco, Inc., Beacon, NY (United States); Oh, M.S. [Hongik Univ., Seoul (Korea, Republic of)


    The Texaco Gasification Process employs a high temperature and pressure slagging gasifier, in which the viscosity of the slag plays a key role in determining operating conditions. The empirical models available in the literature as well as laboratory testing have concentrated on low titanium feeds. During the gasification of waste material, titanium oxide will become an important element in controlling the ash and slag behavior. Slag viscosity was measured at temperatures in the range of 1150-1500{degrees}C under reducing atmosphere with 0-30% titanium in combination with calcium-alumina-silica rich feeds to gain a better understanding of the slag theology. The slag viscosities with most titanium-rich slags showed the behavior of a crystalline slag with T{sub cv} of 1250{degrees}C. Crystalline phase analyses of the slag samples revealed that titanium oxide crystal will nucleate, but the glass phase is dominated by calcium-titanium-silicate and calcium-alumina-silicate glasses which have low melting points.

  14. Smelting reduction and kinetics analysis of magnetic iron in copper slag using waste cooking oil.

    Li, Bo; Wang, Xubin; Wang, Hua; Wei, Yonggang; Hu, Jianhang


    To improve the recovery of copper, the viscosity of copper molten slag is decreased by the reduction of magnetic iron, which, in turn, accelerates the settling and separation of copper droplets from the slag. A new technology is proposed in which waste cooking oil is used as a reductant to reduce magnetic iron in the copper smelting slag and consequently reduce carbon emissions in the copper smelting process. A kinetic model of the reduction of magnetic iron in copper slag by waste cooking oil was built using experimental data, and the accuracy of the model was verified. The results indicated that the magnetic iron content in the copper slag decreased with increasing reduction time and an increase in temperature more efficiently reduced magnetic iron in the copper slag. The magnetic iron in the copper slag gradually transformed to fayalite, and the viscosity of the copper molten slag decreased as the magnetic iron content decreased during the reduction process. The reduction of magnetic iron in the copper molten slag using waste cooking oil was a first-order reaction, and the rate-limiting step was the mass transfer of Fe3O4 through the liquid boundary layer.

  15. The influence of the silicate slag composition on copper losses during smelting of the sulfide concentrates

    Živković Živan


    Full Text Available This paper presents the results of multi-linear regression analysis (MLRA of the slag composition (SiO2, FeO, Fe3O4, CaO, Al2O3 and the content of copper in the matte on resulting copper content in the slag during smelting of the sulfide concentrates in the reverberatory furnace. When comparing results obtained with MLRA model calculations with values measured at industrial level high degree of fitting is obtained (R2 = 0.974. This indicates that slag composition and content of copper in the matte influences the copper losses in the waste slag with the probability of 95 %.

  16. Stabilization effects of surplus soft clay with cement and GBF slag

    LU Jiang; Chirdchanin MODMOLTIN; Katsutada ONITSUKA


    Utilization of industrial waste and surplus construction soft clay as construction material was recommended, and many attempts at geotechnical waste utilization were undertaken. This study aimed at the application of cement and a kind of industrial wastes, i.e. granulated blast furnace slag, on stabilization of surplus soft clay. The results showed that the cement and slag can successfully stabilize Ariake clays even though this high organic clay fails to be stabilized by lime and cement. Addition of slag in cement for stabilization induces higher strength than cement alone for longer curing time. The application of the cement with slag is more suitable than cement alone for stabilization because of economical consideration.

  17. Use of copper slag in glass-epoxy composites for improved wear resistance.

    Biswas, Sandhyarani; Satapathy, Alok


    Copper slag is a by-product obtained during matte smelting and refining of copper. The common management options for copper slag are recycling, recovery of metal and production of value-added products. In the present study using copper slag as a filler in glass-epoxy composites, the tensile modulus increased from 8.77 GPa to 9.64 GPa when using up to 10 wt% of copper slag but on further addition of copper slag (up to 20 wt%), the tensile modulus started to decrease down to 7.11 GPa. Similar trends were observed in the case of flexural strength and interlaminar shear strength. With the incorporation of copper slag particles, the impact strength increased about 10-15%. This work includes the processing, characterization and study of the erosion behaviour of a class of such copper slag filled glass-epoxy composites based on Taguchi's experimental approach to characterise erosion behaviour. The results show that peak erosion takes place at an impingement angle of 60 degrees for the unfilled composites whereas for the copper slag filled glass-epoxy composites it occurs at a 45 degrees impingement angle. This paper considers the possible utilisation of copper slag as filler material for the preparation of composite materials and preparation of added-value products such as abrasive tools, cutting tools and railroad ballast.

  18. Technological progress on detoxification and comprehensive utilization of chromium-containing slag

    柴立元; 何德文; 于霞; 刘恢; 闵小波; 陈为亮


    Chromium salt is an important industrial material, but vast waste slag containing chrome(Ⅵ) is brought out in the process of its production. The slag is seriously harmful to environments and human health. The technologies on detoxification and comprehensive utilization of chromium-containing slag were summarized abroad and at home. And various methods were also described for the detoxification mechanism, technology process, and practical application effects in detail. A new concept for detoxification of chromium-containing slag, furthermore, was put forward by using microorganism.

  19. The Early Strength of Slag Cements with Addition of Hydrate Microcrystals


    The effect of hydrate microcrystals such as calcium silicate hydrates (CSH) and ettringite on the early strength of slag cements was studied.The authors explored the possibility of improving the early strength of the slag cement by applying crystal seed technology.It is shown that slag crystal seeds make the early strength of the cement increased due to the action of hydrate crystal seeds,which speed up the hydration of clinker minerals in the nucleation of ettringite.Therefore,the early strength of the slag cement is obviously improved.

  20. Use of steel slag as a granular material: volume expansion prediction and usability criteria.

    Wang, George; Wang, Yuhong; Gao, Zhili


    The theoretical equation for predicting volume expansion of steel slag is deduced based on both chemical reaction and physical changes of free lime in steel slag during the hydration process. Laboratory volume expansion testing is conducted to compare the results with the theoretical volume expansion. It is proved that they correlated well. It is furthermore experimentally proved that certain volume expansion of steel slag can be absorbed internally by the void volume in bulk steel slag under external surcharge weight making the apparent volume expansion equal zero. The minimum (lowest) absorbable void volume is approximately 7.5%, which is unrelated to the free lime content. A usability criterion is then developed based on the volume expansion of steel slag (%) and the minimum percentage of the volume that can take the volume expansion of steel slag (%). Eventually the criterion (relationship) is established based on the free lime content, the specific gravity and bulk relative gravity of a specific steel slag sample. The criteria can be used as guidance and specification for the use of steel slag and other expansion-prone nonferrous slags, copper, nickel for instance as a granular material in highway construction.

  1. Comparison of possibilities the blast furnace and cupola slag utilization by concrete production

    D. Baricová


    Full Text Available In process of pig iron and cast iron production secondary raw materials and industrial wastes are formed The most abundant secondaryproduct originating in these processes are furnace slag. Blast furnace slag and cupola furnace slag originates from melting of gangue parts of metal bearing materials, slag forming additions and coke ash. In general, slag are compounds of oxides of metallic and non-metallic elements, which form chemical compounds and solutions with each other and also contain small volume of metals, sulfides of metals and gases. Chemical, mineralogical and physical properties of slag determinate their utilisation in different fields of industry.The paper presents results from the research of the blast furnace and cupola furnace slag utilization in the concrete production. Pilotexperiments of the concrete production were performed, by that the blast furnace and cupola furnace slag with a fractions of 0–4mm;4–8mm; 8–16mm were used as a natural substitute. A cupola furnace slag and combination of the blast furnace and cupola furnace slagwere used in the experiments. The analysis results show that such concretes are suitable for less demanding applications.

  2. Heating and melting mechanism of stainless steelmaking dust pellet in liquid slag

    PENG ji; TANG Mo-tang; PENG Bing; YU Di; J.A.KOZINSKl; TANG Chao-bo


    The heating and melting mechanisms of the pellets immersed in liquid slag were investigated. and the effect of the pellet heating and the melting conditions were studied. The results show that the dust component in the pellet is melted from the surface and no metallic elements are melted before the dust component, the time for the pellet completely melted is reduced as the iron powder content increases since the metallic iron has high thermal conductivity. These are four stages of heating and melting of pellet in liquid slag, they are the growth and melt of solid slag shell, penetration of liquid slag, dissolving of dust component and melring of reduced metals.The lifetime of the solid slag shell is in the range of 7-16 s and increasing the pre-heating temperature of the pellet and the slag temperature can shorten the slag shell liretime. The time for the dust component in the pellet to be melted completely is in the range of 20-45 s and increasing the pre-heating temperature, especially in the range of 600-800 ℃.can obviously reduce the melting time. A higher slag temperature can also improvethe pellet melting and the melting time is reduced by l0-15 s when the slag temperature is increased from 1 450 to 1 550 ℃.The pellet with higher content of iron powder is beneficial to the melting by improving the heat conductivity.

  3. Low-Chrome/Chrome Free Refractories for Slagging Gasifiers

    Bennett, J.P.; Kwong, K.-S.; Powell, C.P.; Thomas, H.; Petty, A.V., Jr.


    Gasifiers are containment vessels used to react carbon-containing materials with oxygen and water, producing syngas (CO and H2) that is used in chemical and power production. It is also a potential source of H2 in a future hydrogen economy. Air cooled slagging gasifiers are one type of gasifier, operating at temperatures from 1275-1575º C and at pressures of 400 psi or higher. They typically use coal or petroleum coke as the carbon source, materials which contain ash impurities that liquefy at the gasification temperatures, producing liquid slag in quantities of 100 or more tons/day, depending on the carbon fed rate and the percent ash present in the feedstock. The molten slag is corrosive to refractory linings, causing chemical dissolution and spalling. The refractory lining is composed of chrome oxide, alumina, and zirconia; and is replaced every 3-24 months. Gasifier users would like greater on-line availability and reliability of gasifier liners, something that has impacted gasifier acceptance by industry. Research is underway at NETL to improve refractory service life and to develop a no-chrome or low-chrome oxide alternative refractory liner. Over 250 samples of no- or low-chrome oxide compositions have been evaluated for slag interactions by cup testing; with potential candidates for further studies including those with ZrO2, Al2O3, and MgO materials. The development of improved liner materials is necessary if technologies such as IGCC and DOE’s Near Zero Emissions Advanced Fossil Fuel Power Plant are to be successful and move forward in the marketplace.

  4. Performance of steel-making slag concrete reinforced with fibers

    Ortega-López Vanesa; Fuente-Alonso José Antonio; Skaf Marta; Santamaría Amaia; Aragón Ángel; Manso Juan Manuel


    In this research, the possibility of making concrete reinforced with fibers and manufactured with recycled aggregates from carbon steel production was explored. Electric arc furnace slag (EAFS) was used as coarse and medium aggregate, and part of the sand sizes. Metallic and synthetic fibers were added in different amounts. Initially, the properties of EAFS and their suitability to be used in the manufacture fiber reinforced concrete were analysed. Then, a series of fiber reinforced concrete ...

  5. Slag characterization and removal using pulse detonation for coal gasification. Quarterly research report, July 1--September 31, 1996

    Huque, Z.; Mei, D.; Biney, P.O.; Zhou, J.; Ali, M.R.


    Boiler slagging and fouling as a result of inorganic impurities in combustion gases being deposited on heat transfer tubes have caused severe problems in coal-fired power plant operation. These problems are fuel, system design, and operating condition dependent. Conventional slag and ash removal methods include the use of in situ blowing or jet-type devices such as air or steam soot blowers and water lances. Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. The detonation wave technique based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. These detonation waves have been demonstrated experimentally to have exceptionally high shearing capability important to the task of removing slag and fouling deposits. Several tests have been performed with single shot detonation wave at University of Texas at Arlington to remove the slag deposit. To hold the slag deposit samples at the exit of detonation tube, two types of fixture was designed and fabricated. They are axial arrangement and triangular arrangement. The slag deposits from the utility boilers have been used to prepare the slag samples for the test. The experimental results show that the single shot detonation wave is capable of removing the entire slag (types of slag deposited on economizer, and air-heater, i.e., relatively softer slags) and 30% of the reheater slag (which is harder) even at a distance of 6 in. from the exit of a detonation engine tube. Wave strength and slag orientation also have different effects on the chipping off of the slag. The annual report discusses about the results obtained in effectively removing the slag.

  6. Sulfide Capacity in Ladle Slag at Steelmaking Temperatures

    Allertz, Carl; Sichen, Du


    Sulfide capacity measurements were conducted at 1823 K and 1873 K (1550 °C and 1600 °C) for the quaternary Al2O3-CaO-MgO-SiO2 system, for typical compositions used in the ladle in steelmaking. A copper-slag equilibrium was used under controlled oxygen and sulfur potentials. The sulfide capacity is strongly dependent on the composition and it was found to increase with the basic oxides, while it decreases with increase of the acidic components. It was found that CaO is more effective in holding sulfur in the slag compared to MgO when replacing SiO2. For the present slag compositions, Al2O3 and SiO2 behaved similar with respect to sulfur, and no considerable effect could be recorded when replacing one for the other. The sulfide capacity was also found to be strongly dependent on the temperature, increasing with temperature. The present results were compared with industrial data from the ladle, after vacuum treatment, and they were in good agreement.

  7. Selective Sulfidation of Lead Smelter Slag with Sulfur

    Han, Junwei; Liu, Wei; Wang, Dawei; Jiao, Fen; Qin, Wenqing


    The selective sulfidation of lead smelter slag with sulfur was studied. The effects of temperature, sulfur dosage, carbon, and Na salts additions were investigated based on thermodynamic calculation. The results indicated that more than 96 pct of zinc in the slag could be converted into sulfides. Increasing temperature, sulfur dosage, or Na salts dosage was conducive to the sulfidation of the zinc oxides in the slag. High temperature and excess Na salts would result in the more consumption of carbon and sulfur. Carbon addition not only promoted the selective sulfidation but reduced the sulfur dosage and eliminated the generation of SO2. Iron oxides had a buffering role on the sulfur efficient utilization. The transformation of sphalerite to wurtzite was feasible under reducing condition at high temperature, especially above 1273 K (1000 °C). The growth of ZnS particles largely depended upon the roasting temperature. They were significantly increased when the temperature was above 1273 K (1000 °C), which was attributed to the formation of a liquid phase.

  8. Alternative concrete based on alkali-activated slag

    Puertas, F.


    Full Text Available This article reports the results of related to on the performance of concrete made with waterglass (Na2SiO3•nH2O + NaOH-activated Colombian granulated blast furnace slag. The mechanical strength and durability properties this alkali-activated slag concrete (AAS were compared to the properties of ordinary Portland cement concrete (OPC with the same proportion of binder, which ranged from 340 to 512 kg per m3 of concrete. The results indicated that increasing the proportion of slag led to improvements in the properties studied.El propósito de este artículo es dar a conocer los resultados de la evaluación del comportamiento de mezclas de hormigón producidas a partir de la activación con waterglass (Na2SiO3•nH2O + NaOH de una escoria siderúrgica granulada de alto horno colombiana. Las propiedades mecánicas y de durabilidad de los hormigones activados alcalinamente (AAS se comparan con las correspondientes mezclas de hormigón de cemento Portland (OPC producidas con igual proporción de ligante. Estas proporciones variaron entre 340 y 512 kg por m3 de hormigón. Los resultados obtenidos indican que incrementos en la proporción de la escoria contribuye a la mejora de las propiedades evaluadas.

  9. Blasted copper slag as fine aggregate in Portland cement concrete.

    Dos Anjos, M A G; Sales, A T C; Andrade, N


    The present work focuses on assessing the viability of applying blasted copper slag, produced during abrasive blasting, as fine aggregate for Portland cement concrete manufacturing, resulting in an alternative and safe disposal method. Leaching assays showed no toxicity for this material. Concrete mixtures were produced, with high aggregate replacement ratios, varying from 0% to 100%. Axial compressive strength, diametrical compressive strength, elastic modulus, physical indexes and durability were evaluated. Assays showed a significant improvement in workability, with the increase in substitution of fine aggregate. With 80% of replacement, the concrete presented lower levels of water absorption capacity. Axial compressive strength and diametrical compressive strength decreased, with the increase of residue replacement content. The greatest reductions of compressive strength were found when the replacement was over 40%. For tensile strength by diametrical compression, the greatest reduction occurred for the concrete with 80% of replacement. After the accelerated aging, results of mechanic properties showed a small reduction of the concrete with blasted copper slag performance, when compared with the reference mixture. Results indicated that the blasted copper slag is a technically viable material for application as fine aggregate for concrete mixtures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Application of Improved HMM Algorithm in Slag Detection System

    TAN Da-peng; LI Pei-yu; PAN Xiao-hong


    To solve the problems of ladle slag detection system (SDS),such as high cost,short service life,and inconvenient maintenance,a new SDS realization method based on hidden Markov model (HMM) was put forward.The physical process of continuous casting was analyzed,and vibration signal was considered as the main detecting signal according to the difference in shock vibration generated by molten steel and slag because of their difference in density.Automatic control experiment platform oriented to SDS was established,and vibration sensor was installed far away from molten steel,which could solve the problem of easy power consumption by the sensor.The combination of vector quantization technology with learning process parameters of HMM was optimized,and its revaluation formula was revised to enhance its recognition effectiveness.Industrial field experiments proved that this system requires low cost and little rebuilding for current devices,and its slag detection rate can exceed 95 %.

  11. The Chloride Permeability of Persulphated Phosphogypsum-Slag Cement Concrete

    HUANG Youqiang; LU Jianxin; CHEN Feixiang; SHUI Zhonghe


    The chloride permeability and microstructure of persulphated phosphogypsum-slag cement concrete (PPSCC), the Portland slag cement concrete (PSCC) and ordinary Portland cement concrete (OPCC) were investigated comparatively. Some test methods were used to evaluate the chloride permeability and explain the relationship between the permeability and microstructure of concrete. The results show that the resistance to chloride penetration in PPSCC is signiifcantly better than that in OPCC, the reasons are as follows: 1) the slag in PPSCC is activated by clinker (alkali activation) and phosphogypsum (sulfate activation), forming more low Ca/Si C-S-H gel and gel pores below 10 nm than OPCC, improving the resistance to chloride penetration; 2) the hydration products of PPSCC have a much stronger binding capacity for chloride ions; and 3) in the same mix proportion, PPSCC has a better workability without large crystals calcium hydroxide in the hydration products, the interfacial transition zone (ITZ) is smoother and denser, which can cut off the communicating pores between the pastes and aggregates.

  12. Alkali Aggregate Reaction in Alkali Slag Cement Mortars


    By means of "Mortar Bar Method",the ratio of cement to aggregate was kept as a constant 1∶2.25,the water-cement ratio of the mixture was 0.40,and six prism specimens were prepared for each batch of mixing proportions with dimensions of 10×10×60mm3 at 38±2℃ and RH≥95%, the influences of content and particle size of active aggregate, sort and content of alkali component and type of slag on the expansion ratios of alkali-activated slag cement(ASC) mortars due to alkali aggregate reaction(AAR) were studied. According to atomic absorption spectrometry,the amount of free alkali was measured in ASC mortars at 90d.The results show above factors affect AAR remarkably,but no dangerous AAR will occur in ASC system when the amount of active aggregate is below 15% and the mass fraction of alkali is not more than 5% (Na2O).Alkali participated in reaction as an independent component, and some hydrates containing alkali cations were produced, free alkalis in ASC system can be reduced enormously.Moreover,slag is an effective inhibitor, the possibility of generating dangerous AAR in ASC system is much lower at same conditions than that in ordinary Portland cement system.

  13. Simulation of past exposure in slag wool production.

    Fallentin, B; Kamstrup, O


    A survey of the working conditions at a Danish slag wool production factory during the early technological phase in the 1940s is presented. No exposure data, however, are available for that period. So, a full-scale simulation of the past production of slag wool has been performed. Air monitoring was carried out in the working area around the cupola furnace. The aim was to measure exposure to air pollutants other than fibres. Such exposure might have confounded a possible association between lung cancer and exposure to fibres, in the early technological phase of slag wool production. The simulation experiment demonstrated exposure to PAH, a known lung carcinogen. The effect of other concurrent exposures is difficult to assess. Time-weighted average concentrations of particulate material ranged between 12.9 and 49.1 mg m-3 at the upper decks around the cupola. Corresponding concentrations of the dominant metals zinc and lead were 4.4-22.7 mg Zn m-3 and 0.9-4.7 mg Pb m-3. Significant concentrations of PAH up to 269 micrograms PAH m-3 (4 micrograms BaP m-3) occurred during ignition of the cupola furnace. The carbon monoxide level reached 270 ppm also during ignition.

  14. Speciation of copper in the thermally stabilized slag

    Tuan, Y.-J. [Department of Environmental Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Paul Wang, H., E-mail: [Department of Environmental Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Chang, J.-E. [Department of Environmental Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Chao, C.-C. [Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Tsai, C.-K. [Department of Environmental Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)


    The Taiwan universities laboratory hazardous wastes have been treated by incineration at the temperature range of 1173-1273 K. By X-ray absorption near edge structure (XANES) spectroscopy, mainly CuO and CuSO{sub 4} are found in the incineration bottom and fly ashes. The incineration fly ash can be stabilized thermally at 1773 K in the plasma melting reaction chamber (integrated with the incinerator), and converted to slag. The concentration of leachable copper in the slag is reduced significantly mainly due to the fact that copper is encapsulated in the SiO{sub 2} matrix. In addition, the refined extended X-ray adsorption fine structure (EXAFS) spectra of copper also indicate formation of the Cu-O-Si species in the slag as the bond distances of 1.95 A for Cu-O and 2.67 A for O-Si are observed. This work exemplifies utilization of the synchrotron X-ray absorption spectroscopy to facilitate the thermal stabilization treatments of the fly ash hazardous waste using the plasma melting method.

  15. Estimation of slagging in furnaces; Kuonaavuuden ennustaminen kivihiilen poelypoltossa

    Jacobson, T.; Jaeaeskelaeinen, K.; Oeini, J.; Koskiahde, A.; Jokiniemi, J.; Pyykkoenen, J. [Imatran Voima Oy, Vantaa (Finland)


    Understanding and estimation of slagging in furnaces is essential in the design of new power plants with high steam values or in modifications like low-NO{sub x} retrofits in existing furnaces. Major slagging yields poor efficiency, difficult operation and high maintenance costs of the plant. The aim of the project is to develop a computational model for slagging in pulverized coal combustion. The model is based on Computer Controlled Scanning Electron Microscopy (CCSEM) analysis of mineral composition of the coal and physical models for behaviour of minerals inside a furnace. The analyzed mineral particles are classified to five composition classes and distributed to calculational coal particles if internal minerals of coal. The calculational coal particles and the external minerals are traced in the furnace to find out the behaviour of minerals inside the furnace. If the particle tracing indicates that the particle hits the heat transfer surface of the furnace the viscosity of the particle is determined to see if particle is sticky. The model will be implemented to 3D computational fluid dynamics based furnace simulation environment Ardemus which predicts the fluid dynamics, heat transfer and combustion in a furnace. (orig.)

  16. Prebiotic phosphorus chemistry reconsidered

    Schwartz, A. W.; Orgel, L. E. (Principal Investigator)


    The available evidence indicates that the origin of life on Earth certainly occurred earlier than 3.5 billion years ago and perhaps substantially earlier. The time available for the chemical evolution which must have preceded this event is more difficult to estimate. Both endogenic and exogenic contributions to chemical evolution have been considered; i.e., from chemical reactions in a primitive atmosphere, or by introduction in the interiors of comets and/or meteorites. It is argued, however, that the phosphorus chemistry of Earth's earliest hydrosphere, whether primarily exogenic or endogenic in origin, was most likely dominated by compounds less oxidized than phosphoric acid and its esters. A scenario is presented for the early production of a suite of reactive phosphonic acid derivatives, the properties of which may have foreshadowed the later appearance of biophosphates.

  17. [Phosphorus intake and osteoporosis].

    Omi, N; Ezawa, I


    Phosphorus (P) is one of the most important nutrients for bone metabolism, such as calcium. In general, P intake is usually adequate in our daily diet, and there is a risk of over-consumption from processed food. On the other hand, Ca intake is not always adequate from the Japanese daily diet. When Ca/P is taken from the daily diet at a level of 0.5 - 2.0, the P intake level dose not affect intestinal Ca absorption. Therefore, it is important not only to pay attention to preventing the over-consumption of P, but also to obtain a sufficient intake of Ca. For the prevention of osteoporosis, it is important to consume sufficient Ca and to maintain and appropriate Ca/P balance from diet.

  18. Electric Conductivity of Phosphorus Nanowires

    ZHANG Jing-Xiang; LI Hui; ZHANG Xue-Qing; LIEW Kim-Meow


    We present the structures and electrical transport properties of nanowires made from different strands of phosphorus chains encapsulated in carbon nanotubes. Optimized by density function theory, our results indicate that the conductance spectra reveal an oscillation dependence on the size of wires. It can be seen from the density of states and current-voltage curves that the structure of nanowires affects their properties greatly. Among them,the DNA-like double-helical phosphorus nanowire exhibits the distinct characteristic of an approximately linear I - V relationship and has a higher conductance than others. The transport properties of phosphorus nanowires are highly correlated with their microstructures.

  19. Thermodynamic simulation of the effect of slag chemistry on the corrosion behavior of alumina-chromia refractory

    Shi-xian Zhao; Bin-li Cai; Hong-gang Sun; Gang Wang; Hong-xia Li; and Xiao-yan Song


    The corrosion behavior of alumina–chromia refractory against two kinds of industrial slags (coal slag and iron smelting slag) at 1550°C was investigated via thermodynamic simulations. In the proposed simulation model, the initial slag first attacks the matrix and sur-face aggregates and subsequently attacks the inner aggregates. The simulation results indicate that the slag chemistry strongly affects the phase formation and corrosion behavior of the refractory brick. Greater amounts of alumina were dissolved and spinel solid phases formed when the brick interacted with iron smelting slag. These phenomena, as well as the calculated lower viscosity, may lead to much deeper penetration than that exhibited by coal slag and to more severe corrosion compared to that induced by coal slag. The thermodynamic calcula-tions well match the experimental observations, demonstrating the efficiency of the proposed simulation model for evaluating the corrosion behavior of alumina–chromia refractory.

  20. Disponibilidade de fósforo pelos extratores de Mehlich 1 e Resina em Latossolo Vermelho Amarelo, álico cultivado com três gramíneras forrageiras Availability of phosphorus by the Mehlich 1 and Resin methods in a Red Yellow Latosol cultivated with three grasses

    L. de A. Corrêa


    Full Text Available É apresentado um estudo comparando os extratores de Mehlich 1 e Resina na avaliação do P disponível em Latossolo Vermelho Amarelo, álico cultivado com as gramíneas Brachiaria decumbens Stapf, Brachiaria brizantha (Hochst. Stapf. cv. Marandu e Panicum maximum Jacq. Foram utilizados dados de dois ensaios de adubação fosfatada, um realizado em vasos em casa de vegetação e o outro no campo. Correlações entre o P extraído através de cada extrator com a produção relativa de matéria seca, o P extraído peía planta e o teor de P na planta, permitiram determinar o extrator de P mais eficiente. Os resultados mostraram que os dois extratores foram eficientes e similares na avaliação do P disponível para as três gramíneas forrageiras, sendo que o método da Resina apresentou maior capacidade de extração do P aplicado.This study was undertaken to compare the Mehlich 1 and Resin methods in the evaluation of available P in a Red Yellow Latossol, cultivated with Brachiaría decumbens Stapf., Brachiaría brízantha (Hochst. Stapf cv. Marandu and Panicum maximum Jacq. Data of two experiments of P fertilization were utilized, one carried out in the greenhouse and the other in the field. Correlations between the amount of P extracted by each extrator with the relative production of dry matter and of the amount of P extracted by the plant and the level of P in the plant, were used to determine the efficiency of the extractors. The results showed that both extractors were efficient and similar for the evaluation of the P availability of the three grasses, but the resin method had a greater extraction capacity of the P applied.

  1. Geophysical Investigation of Buried Slag at the Parrot Tailings Site, Butte, Montana

    Ha, C. D. M.; Shepherd, K.; Mack, A.; Rutherford, B. S.; Speece, M. A.


    Butte, Montana, has served as an important mining district for more than 120 years. This area contains historic mine waste from decades of unregulated mining practices. In July 1881, the Parrot smelter in Butte started operations and was soon processing ore and producing copper. The Parrot smelter also had a concentrating plant that treated the ore prior to smelting. The Parrot smelter wastes (slag and tailings) were later covered with Berkeley Pit crushed quartz monzonite overburden. The slag is bricked because it was deposited hot and, as a consequence forms a laterally extensive, cohesive, hard body that is difficult to remove without blasting. With the mine waste being covered by unknown quantities of overburden and soil throughout the area, and core data being limited and expensive to retrieve, the only economical method of discovery is geophysics. Several geophysical techniques were used to determine the lateral boundaries and depth of the buried slag body. The geophysical methods used were seismic, gravity, electromagnetic induction, and magnetics. Not all of these geophysical surveys produced useful results due to the nature of the slag. For instance, electromagnetic induction could not distinguish between the slag and adjacent tailings; and, the microgravity profiles showed only a small gravitational field variation caused by the density contrast between slag and the surrounding tailings, sediment and granitic cover. On the other hand, the seismic surveys resulted in unexpected first arrival times that distinctly showed velocity variations due to the slag. In addition, the slag body produced a large magnetic response. Unpublished, proprietary well data allowed us to model the slag body from our magnetic data. This model was confirmed by projecting velocity tomograms, that we created using seismic diving waves, onto our magnetic models. Model results were combined to form a three-dimensional image of the slag body. These results will be used to help

  2. Recycling of residual IGCC slags and their benefits as degreasers in ceramics.

    Iglesias Martín, I; Acosta Echeverría, A; García-Romero, E


    This work studies the evolution of IGCC slag grains within a ceramic matrix fired at different temperatures to investigate the effect of using IGCC slag as a degreaser. Pressed ceramic specimens from two clay mixtures are used in this study. The M1 mixture is composed of standard clays, whereas the M2 mixture is composed of the same clay mixture as M1 mixture but contains 15% by weight IGCC slag. The amount of IGCC slag added coincides with the amount of slag typically used as a degreaser in the ceramic industry. Specimens are fired at 950 °C, 1000 °C, 1050 °C, 1100 °C and 1150 °C. The mineralogical composition and the IGCC slag grain shape within the ceramic matrix are determined by X-ray diffraction, polarized light microscopy and scanning electron microscopy. The results reveal that the surface of the slag grains is welded to the ceramic matrix while the quartz grains are separated, which causes increased water absorption and reduces the mechanical strength. IGCC slag, however, reduces water absorption. This behaviour is due to the softening temperature of the slag. This property is quite important from an industrial viewpoint because IGCC slag can serve as an alternative to traditional degreasing agents in the ceramic building industry. Additionally, using IGCC slag allows for the transformation of waste into a secondary raw material, thereby avoiding disposal at landfills; moreover, these industrial wastes are made inert and improve the properties of ceramics.

  3. Selective Crystallization Behavior of CaO-SiO2-Al2O3-MgO-FetO-P2O5 Steelmaking Slags Modified through P2O5 and Al2O3

    Wang, Zhanjun; Sun, Yongqi; Sridhar, Seetharaman; Zhang, Mei; Guo, Min; Zhang, Zuotai


    In this study, the selective crystallization behavior of synthetic FetO-rich steelmaking slags modified by P2O5 and Al2O3 additions was explored using non-isothermal differential scanning calorimetry, X-ray diffraction, and field emission scanning electron microscopy techniques. Continuous cooling transformation diagrams of Fe-enriched and P-enriched phases were constructed. It was found that P2O5 addition can suppress the crystallization due to the increasing viscosity caused by increasing degree of polymerization; however, an increase of Al2O3 content accelerated the precipitation of dystectic MgFeAlO4, copolymerized by [AlO4]-tetrahedra and [FeO4]-tetrahedra units. It was also noted that the content of phosphorus in P-enriched phase can reach a high value as 28.71 wt pct for the slags modified by 15.17 wt pct Al2O3. The non-isothermal crystallization kinetics derived from activation energy and the structure of the slags explained by Raman spectra were further analyzed, which was well in accordance with the above analysis.

  4. Total Phosphorus in Surface Water

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALP is reported in kilograms/hectare/year. More information about these resources, including the...

  5. Dietary phosphorus and kidney disease.

    Uribarri, Jaime


    High serum phosphate is linked to poor health outcome and mortality in chronic kidney disease (CKD) patients before or after the initiation of dialysis. Therefore, maintenance of normal serum phosphate levels is a major concern in the clinical care of this population with dietary phosphorus restriction and/or use of oral phosphate binders considered to be the best corrective care. This review discusses (1) evidence for an association between serum phosphate levels and bone and cardiovascular disease (CVD) in CKD patients as well as progression of kidney disease itself; (2) the relationship between serum phosphate and dietary phosphorus intake; and (3) implications from these data for future research. Increasing our understanding of the relationship between altered phosphorus metabolism and disease in CKD patients may clarify the potential role of excess dietary phosphorus as a risk factor for disease in the general population.

  6. Phosphorus balance with daily dialysis.

    Kooienga, Laura


    Hyperphosphatemia is an almost universal finding in patients with end-stage renal disease and is associated with increased all-cause mortality, cardiovascular mortality, and vascular calcification. These associations have raised the question of whether reducing phosphorus levels could result in improved survival. In light of the recent findings that increased per-session dialysis dose, as assessed by urea kinetics, did not result in improved survival, the definition of adequacy of dialysis should be re-evaluated and consideration given to alternative markers. Two alternatives to conventional thrice weekly dialysis (CHD) are nocturnal hemodialysis (NHD) and short daily hemodialysis (SDHD). The elimination kinetics of phosphorus as they relate to these alternative daily dialysis schedules and the clinical implications of overall phosphorus balance are discussed here. The total weekly phosphorus removal with NHD is more than twice that removed by CHD (4985 mg/week +/- 1827 mg vs. 2347 mg/week +/- 697 mg) and this is associated with a significantly lower average serum phosphorous (4.0 mg/dl vs. 6.5 mg/dl). In spite of the observed increase in protein and phosphorus intake seen in patients on SDHD, phosphate binder requirements and serum phosphorus levels are generally stable to decrease although this effect is strongly dependent on the frequency and overall treatment time.

  7. Analysis Of Separation Mechanism Of The Metallic Phase Of Slag In The Direct-To-Blister Process

    Bydałek A.W.


    Full Text Available The article discusses the structure of the slag in the liquid state, the properties and interactions within the slag. The analysis of structures occurring in slag suspension were presented with regard to differences in chemical composition in micro-areas. Two different mechanisms for formation of precipitates in Cu-Fe-Pb alloys during extraction were showed.

  8. Utilization of lightweight materials made from coal gasification slags. Quarterly report, December 1, 1995--February 28, 1996



    The project scope consists of collecting a 20-ton sample of slag (primary slag), processing it for chart removal, and subjecting it to pyroprocessing to produce expanded slag aggregates of various size gradations and unit weights, ranging from 12 to 50 lb/fg{sup 3}. A second smaller slag sample will be used for confirmatory testing. The expanded slag aggregates will then be tested for their suitability in manufacturing precast concrete products (e.g., masonry blocks and roof tiles) and insulating concrete, first at the laboratory scale and subsequently in commercial manufacturing plants. These products will be evaluated using ASTM and industry test methods. Technical data generated during production and testing of the products will be used to assess the overall technical viability of expanded slag production. In addition, a market assessment will be made based on an evaluation of both the expanded slag aggregates and the final products, and market prices for these products will be established in order to assess the economic viability of these utilization technologies. Relevant cost data for physical and pyroprocessing of slag to produce expanded slag aggregates will be gathered for comparison with (1) the management and disposal costs for slag or similar wastes and (2) production costs for conventional materials which the slag aggregates would replace. This will form the basis for an overall economic evaluation of expanded slag utilization technologies.

  9. Nitrogen and Phosphorus Removal Performance in the Novel Multi-Layered Biological Tricking Filter

    CUI Ting-ting


    Full Text Available Biological trickling filter is one of the main rural sewage treatment technology, but it still has the shortcomings such as lower re-moval efficiency for nitrogen and phosphorus or lower stability. In order to improve the nitrogen and phosphorus removal efficiency of the de-vice and find out its optimum technological conditions, the study took the novel multi-layered biological tricking filter as the device to test the contribution of filter medium, hydraulic loading, recirculation ratio on the treatment of nitrogen and phosphorus removal. The results showed that when the hydraulic loading of 4 m3·m-2·d-1, the recirculation ratio rate of 2∶1 and slag as filter medium were applied, the best effect could be achieved in the filter. The highest mean efficiency of NH4+-N, TN, TP and COD were 87.08%, 57.37%, 66.04% and 80.78%, respectively.The results also indicated that higher recirculation ratio was one of effective paths to improve nitrogen removal efficiency.

  10. Níveis críticos de fósforo para o estabelecimento de gramíneas forrageiras em Latossolo Vermelho-Amarelo, álico. I: ensaio em casa de vegetação Critical levels of phosphorus for the establishment of pasture grasses on a Red Yellow Latosol. I: greenhouse test

    L. de A. Corrêa


    Full Text Available O estudo, desenvolvido em casa de vegetação, teve por objetivos determinar os níveis críticos de P no solo, avaliados pelos extratores de Mehlich I e Resina e na planta, para o estabelecimento das gramíneas Brachiaria decumbens Stapf., Brachiaria brizantha (Ilochst. Stapf. cv. Marandu e Panicum maximum Jacq., em Latossolo Vermelho Amarelo, álico. O delineamento experimental foi o de blocos casualizados com quatro repetições, no esquema fatorial: 7 (doses de P x 3 (gramíneas. As doses de P corresponderam a 0; 17,5; 35,0; 70,0; 140,0; 280,0 e 560,0 ppm. Foram realizados dois cortes, o primeiro 50 dias após a semeadura e o segundo com 30 dias de rebrota. Não foram constatadas diferenças entre as espécies quanto à exigência em P para o seu estabelecimento. Os níveis críticos de P no solo, para 80% do crescimento máximo, no primeiro corte, variaram de 8,0 a 12,0 ppm (Mehlich I e de 13,0 a 18,0 ppm (Resina para as três espécies forrageiras. No segundo corte foram de 11,5; 12,0 e 14,0 ppm (Mehlich I e de 18,0; 22,0 e 24,0 ppm (Resina, para a Brachiaria decumbens, Brachiaria brizaníha e o Panicum maximum, respectivamente. Os níveis críticos de P na planta foram, na mesma ordem, de 0,11; 0,13 e 0,12%, no primeiro corte e de 0,09; 0,12 e 0,10%, no segundo corte.The objectives of the present study, carried out in a greenhouse, were to determine the critical levels of soil P, by the Mehlich I and Resin extractors, and in the plant, for the stablishment of pastures of Brachiaría decumbens Stapf., Brachiaría brizaníha (Ilochst. Stapf cv. Marandu and Panicum maximum JACK., on a Red Yellow Latosol. The experimental design was a randomized complete block with four replications and 21 treatments (7 levels of P x 3 species. The levels of P were: 0; 17.5; 35.0; 70.0; 140.0; 280.0 and 560.0 ppm. Two shoot cuts of plants were done: the first, fifty days after sowing and the second, thirty days later. No differences in P requeriment for crop

  11. Study of Phase Relations of ZnO-Containing Fayalite Slag Under Fe Saturation

    Shi, Huayue; Chen, Liugang; Malfliet, Annelies; Jones, Peter Tom; Blanpain, Bart; Guo, Muxing


    A ZnO-containing fayalite-based slag can be formed in copper smelting from secondary raw materials and its high viscosity is a common issue that hinders slag tapping. In this work, the crystallization behavior of the industrial slag was observed in situ by confocal laser scanning microscopy. Solid precipitation was found to be the major cause of the poor slag fluidity. The phase relations in the industrial slag system ZnO-"FeO"-SiO2-Al2O3-CaO (CaO/SiO2 = 0.05, Al2O3/SiO2 = 0.15) were investigated by quenching the samples after reaching equilibrium at 1423 K (1150 °C) under iron saturation. The equilibrium composition of the phases was determined with electron probe micro-analysis. The effect of individual components, such as FeO, ZnO, and CaO on the phase equilibrium of the slag system has been quantitatively studied. The relation between the solid-phase fraction and the chemical composition of the slag has been revealed. Suggestions to modify the slag composition toward low viscosity are provided.

  12. Physico-chemical characterization of steel slag. Study of its behavior under simulated environmental conditions.

    Navarro, Carla; Díaz, Mario; Villa-García, María A


    The chemical and mineralogical composition of steel slag produced in two ArcelorMittal steel plants located in the North of Spain, as well as the study of the influence of simulated environmental conditions on the properties of the slag stored in disposal areas, was carried out by elemental chemical analysis, XRF, X-ray diffraction, thermal analysis, and scanning electron microscopy with EDS analyzer. Spectroscopic characterization of the slag was also performed by using FTIR spectroscopy. Due to the potential uses of the slag as low cost adsorbent for water treatment and pollutants removal, its detailed textural characterization was carried out by nitrogen adsorption-desorption at 77 K and mercury intrusion porosimetry. The results show that the slag is a crystalline heterogeneous material whose main components are iron oxides, calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate), elemental iron, and quartz. The slags are porous materials with specific surface area of 11 m(2)g(-1), containing both mesopores and macropores. Slag exposure to simulated environmental conditions lead to the formation of carbonate phases. Carbonation reduces the leaching of alkaline earth elements as well as the release of the harmful trace elements Cr (VI) and V. Steel slags with high contents of portlandite and calcium silicates are potential raw materials for CO(2) long-term storage.

  13. Superconducting magnetic separation of ground steel slag powder for recovery of resources

    Kwon, H. W.; Kim, J. J.; Kim, Young Hun [Andong National University, Andong (Korea, Republic of); Ha, D. W. [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of); Choi, J. H. [Dept. of Environmental Engineering, Catholic University of Pusan, Pusan (Korea, Republic of)


    Steel slag has been considered as an industrial waste. A huge amount of slag is produced as a byproduct and the steel slag usually has been dumped in a landfill site. However the steel slag contains valuable resources such as iron, copper, manganese, and magnesium. Superconducting magnetic separation has been applied on recovery of the valuable resources from the steel slag and this process also has intended to reduce the waste to be dumped. Cryo-cooled Nb-Ti superconducting magnet with 100 mm bore and 600 mm of height was used as the magnetic separator. The separating efficiency was evaluated in the function of magnetic field. A steel slag was ground and analyzed for the composition. Iron containing minerals were successfully concentrated from less iron containing portion. The separation efficiency was highly dependent on the particle size giving higher separating efficiency with finer particle. The magnetic field also effects on the separation ratio. Current study showed that an appropriate grinding of slag and magnetic separation lead to the recovery of metal resources from steel slag waste rather than dumping all of the volume.

  14. Substrate pH and butterfly bush response to dolomitic lime or steel slag amendment

    Steel slag is a fertilizer amendment with a high concentration of calcium oxide, and thus capable of raising substrate pH similar to dolomitic lime. Steel slag, however, contains higher concentrations of some nutrients, such as iron, manganese, and silicon, compared to dolomitic lime. The objectiv...

  15. Novel Approach for Modeling of Nonuniform Slag Layers and Air Gap in Continuous Casting Mold

    Wang, Xudong; Kong, Lingwei; Yao, Man; Zhang, Xiaobing


    Various kinds of surface defects on the continuous casting slab usually originate from nonuniform heat transfer and mechanical behavior, especially during the initial solidification inside the mold. In this article, a model-coupled inverse heat transfer problem incorporating the effect of slag layers and air gap is developed to study the nonuniform distribution of liquid slag, solid slag, and air gap layers. The model considers not only the formation and evolution of slag layers and air gap but also the temperatures in the mold copper as measured by thermocouples. The simulation results from the model and the measured temperatures from experiments are shown to be in good agreement with each other. At the casting speed of 0.65 m/min, the liquid slag film disappears and transforms into solid slag entirely at about 400 mm away from meniscus, and an air gap begins to form. Until the mold exit, the maximum thickness of the solid slag layer and air gap gradually increases to 1.34 and 0.056 mm, respectively. The results illustrate that the magnitude and nonuniform distribution of the slag layers and air gap along the cross direction, correlating with heat flux between the shell and mold, eventually determine the temperature profiles of the mold hot face and slab surface. The proposed model may provide a convenient approach for analyzing nonuniform heat transfer and mechanical behaviors between the mold and slab in the real casting process.

  16. Behaviour of fibre reinforced concrete using steel slag coarse aggregate produced in Qatar

    Alnahhal Wael


    Full Text Available The state of Qatar suffers from the shortage of natural resources needed for concrete production. Therefore, it is essential to investigate the feasibility of using by-product recycled materials as aggregates to maintain the concrete construction industry. Several types of recyclable materials are currently used in concrete. One of the potential resources of recycled concrete is steel slag. Knowing that Steel slag is the most significant solid waste generated by Qatar Steel Company in Qatar, replacing of natural coarse aggregate with steel slag aggregate will have a significant environmental and economic impact to the state of Qatar. This paper presents the compression and flexural test results of different concrete mixes made of steel slag coarse aggregate combined with a newly developed basalt chopped fibres. The parameters investigated included the volume fraction of the fibre used and the type of coarse aggregates (natural aggregates “Gabbro” and steel slag aggregates. Plain concrete specimens containing natural coarse aggregates and steel slag aggregates with no fibres added were also tested to serve as control. Test results showed that adding the basalt chopped fibres to the concrete mixes enhanced their flexural tensile strengths at different percentages. In addition, the compressive strength of concrete made with steel slag aggregate was higher than that made with natural gabbro aggregate. Test results clearly showed that steel slag aggregates can be used as sustainable and eco-friendly alternative materials in concrete structures.

  17. The Effect of Solid Constituent Particle Size Distributions on TP-H1148 Propellant Slag

    May, Douglas H.; Miles, William L.; Taylor, David S.; Rackham, Jon L.


    Special aluminum and ammonium perchlorate (AP) particle size distributions were prepared for a matrix of five-inch diameter, center-perforated (CP) motor tests to measure the aluminum oxide slag response in Space Shuttle Reusable Solid Rocket Motor (RSRM) propellant. Previous tests of TP-H1148 propellant in five-inch CP spin motors have shown a correlation between aluminum particle size and generated slag. The motors for this study were cast from thirteen five-gallon propellant mixes which used five particle size levels of aluminum powder, five of unground AP and three of ground AP. Aluminum had the greatest effect on slag formation, the more coarse fractions causing greater slag quantities and larger slag particles. Unground AP had about half the effect of aluminum with the coarser fractions again producing more and larger sized slag particles. The variation in ground AP did not have a significant effect on slag formation. Quench bomb tests showed the same trends as the spin motors, that is, larger aluminum and AP particle size distributions generated larger slag particles leaving the propellant surface. Cured propellant mechanical properties were also impacted by particle size variation.

  18. Slag optimization in charcoal blast furnaces; Otimizacao de escorias de altos-fornos a carvao vegetal

    Castro, Luiz Fernando Andrade de; Tavares, Roberto Parreiras; Figueira, Renato Minelli; Lopes, Leonardo Braga Polido; Goncalves, Alexandre Ferreira [Associacao Brasileira de Metais (ABM), Sao Paulo, SP (Brazil)


    In this work, it is shown the optimum composition of charcoal blast furnace slag using phase diagrams. The results are compared with industrial data and some possible changes in slag composition and mass are also suggested. (author) 3 refs., 5 figs., 3 tabs.


    Sultan A. Tarawneh


    Full Text Available This study presents an evaluation of the physical and mechanical properties and characteristics of steel slag aggregate concrete in comparison with the typical crushed limestone stone aggregate concrete. Hardened concrete consist of more than 70% aggregate due to the high demand in building construction and the increase of the amount of disposed waste material, suppliers and researchers are exploring the use of alternative materials which could preserve natural sources and save the environment. In this study, steel slag was used as an aggregate replacement in conventional concrete mixes. Steel slag which is mainly consists of calcium carbonate is produced as a by-product during the oxidation process in steel industry. Steel slag was selected due to its characteristics, which are almost similar to conventional aggregates and the fact that it is easily obtainable as a by-product of the steel industry. As a result, utilization of steel slag will save natural resources and clean environment. Furthermore, results have shown that slag aggregate has better abrasion factor and impact value than conventional aggregate. Thorough investigation of the results have indicated that the amount of increase in compressive strength at age of 7 days are much more than that of age 28 days for all types of aggregate replacement. This indicates that the added slag could work as accelerator at early age while at 28 days age, the effect is reduced. The fine slag replacement scores the highest effect.

  20. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    Yongqi Sun


    Full Text Available Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have been exploited and performed including methane reforming, coal and biomass gasification, and direct compositional modification and utilization of slags. These methods effectively meet the challenges mentioned before and help integrate the steel industry with other industrial sectors. During the heat recovery using chemical methods, slags can act as not only heat carriers but also as catalysts and reactants, which expands the field of utilization of slags. Fuel gas production using the waste heat accounts for the main R&D trend, through which the thermal heat in the slag could be transformed into high quality chemical energy in the fuel gas. Moreover, these chemical methods should be extended to an industrial scale to realize their commercial application, which is the only way by which the substantial energy in the slags could be extracted, i.e., amounting to 16 million tons of standard coal in China.

  1. Characterization and activation of the slag of El Hadjar's blast furnaces by clinkers

    Guetteche, M.N.; Houari, H. [Constantine Univ. (France)


    The El Hadjar steel plant in Algeria produces about 430,000 tons of slag annually. This paper presents a study in which the granular slag of El Hadjar's blast furnace was characterized using a variety of analytical methods that made it possible to calculate hydraulic indices. El Hadjar slag is being promoted in the construction industry in an effort to address environmental concerns regarding the production of portland cement which is very energy intensive and which contributes to major greenhouse gas emissions into the atmosphere. The use of slag as an addition to portland cement or the manufacturing of clinker free binder would make this waste into a valuable product. Chemical analysis, x-ray diffraction, differential thermal analysis, Fourier transformer infrared spectrometry and conductimetry were used to better understand the vitreous structure of the slag and its hydraulic reactivity. Prismatic test tubes were used for the mechanical tests which involved clinkers of various grinding rates of slag. The results showed that slag is reactive and that the evolution of mechanical resistance to grinding is very sensitive. It was also shown that long term mechanical performance of the slag based ingredients are of significant interest to the cement and concrete industry. 9 refs., 9 tabs., 5 figs.

  2. Microstructure and Composition of Hydration Products of Ordinary Portland Cement with Ground Steel-making Slag

    LI Yong-xin; CHEN Yi-min; ZHANG Hong-tao; HE Xing-yang; WEI Jiang-xiong; ZHANG Wen-sheng


    The effect of ground steel-making slag on microstructure and composition of hydration products of ordinary Portland cement (OPC) was investigated by mercury intrusion porosimetry ( MIP ), X- ray diffraction (XRD) and differential thermal analysis (DTA). Results show that ground steel-making slag is a kind of high activity mineral additives and it can raise the longer-age strength of OPC mortar. The total porosity and average pore diameter of OPC paste with groand steel-making slag increase with the increase of the amount of ground steelmaking slag replacing OPC at various ages, while after 28 days most pores in OPC paste with ground steel-making slag do not influeace the strength because the diameter of those pores is in the rang of 20 to 50nm. The hydration mechanism of ground steel-making slag is similar to that of OPC but different from that of fly ash and blast furnace slag. The hydration products of ground steel-making slag contain quite a lot of Ca( OH)2 in long age.

  3. Effect of Slag Chemistry on the Desulfurization Kinetics in Secondary Refining Processes

    Kang, Jin Gyu; Shin, Jae Hong; Chung, Yongsug; Park, Joo Hyun


    Desulfurization behavior was investigated based on a wide slag composition and working temperature range. Moreover, the rate-controlling step (RCS) for desulfurization with regard to the ladle-refining conditions and the transition of the RCS by changing the slag composition was systematically discussed. The desulfurization ratio reached an equilibrium value within approximately 15 minutes irrespective of the CaO/Al2O3 (=C/A = 1.3 to 1.9) and CaO/SiO2 (=C/S = 3.8 to 6.3) ratios. However, the desulfurization behavior of less basic slags (C/A = 1.1 or C/S = 1.9) exhibited a relatively sluggish [S]-decreasing rate as a function of time. The equilibrium S partition ratio increased with an increase in slag basicity (C/A and C/S ratio), not only due to an increase in sulfide capacity but also due to a decrease in oxygen activity in the molten steel. There was a good correlation between the calculated and measured S partition ratios at various slag compositions. However, the measured S partition ratio increased by adding 5 pct CaF2, followed by a constant value. Multiphase slag exhibited a relatively slow desulfurization rate compared to that of fully liquid slag, possibly due to a decrease in the effective liquid slag volume, interfacial reaction area, and a relatively slow slag initial melting rate due to a high melting point. The activation energy of the desulfurization process was estimated to be 58.7 kJ/mol, from which it was proposed that the desulfurization reaction of molten steel via CaO-Al2O3-SiO2-MgO-CaF2 ladle slag was generally controlled by the mass transfer of sulfur in the metal phase. However, there was a transitional period associated with the rate-controlling mechanism due to a change in the physicochemical properties of the slag. For slag with a viscosity greater than about 1.1 dPa·s and an equilibrium S partition ratio lower than about 400, the overall mass-transfer coefficient was affected by the slag properties. Hence, it was theoretically and

  4. Effect of Slag Chemistry on the Desulfurization Kinetics in Secondary Refining Processes

    Kang, Jin Gyu; Shin, Jae Hong; Chung, Yongsug; Park, Joo Hyun


    Desulfurization behavior was investigated based on a wide slag composition and working temperature range. Moreover, the rate-controlling step (RCS) for desulfurization with regard to the ladle-refining conditions and the transition of the RCS by changing the slag composition was systematically discussed. The desulfurization ratio reached an equilibrium value within approximately 15 minutes irrespective of the CaO/Al2O3 (=C/A = 1.3 to 1.9) and CaO/SiO2 (=C/S = 3.8 to 6.3) ratios. However, the desulfurization behavior of less basic slags (C/A = 1.1 or C/S = 1.9) exhibited a relatively sluggish [S]-decreasing rate as a function of time. The equilibrium S partition ratio increased with an increase in slag basicity (C/A and C/S ratio), not only due to an increase in sulfide capacity but also due to a decrease in oxygen activity in the molten steel. There was a good correlation between the calculated and measured S partition ratios at various slag compositions. However, the measured S partition ratio increased by adding 5 pct CaF2, followed by a constant value. Multiphase slag exhibited a relatively slow desulfurization rate compared to that of fully liquid slag, possibly due to a decrease in the effective liquid slag volume, interfacial reaction area, and a relatively slow slag initial melting rate due to a high melting point. The activation energy of the desulfurization process was estimated to be 58.7 kJ/mol, from which it was proposed that the desulfurization reaction of molten steel via CaO-Al2O3-SiO2-MgO-CaF2 ladle slag was generally controlled by the mass transfer of sulfur in the metal phase. However, there was a transitional period associated with the rate-controlling mechanism due to a change in the physicochemical properties of the slag. For slag with a viscosity greater than about 1.1 dPa·s and an equilibrium S partition ratio lower than about 400, the overall mass-transfer coefficient was affected by the slag properties. Hence, it was theoretically and

  5. Effect of Slag on Titanium, Silicon, and Aluminum Contents in Superalloy During Electroslag Remelting

    Jiang, Zhou-Hua; Hou, Dong; Dong, Yan-Wu; Cao, Yu-Long; Cao, Hai-Bo; Gong, Wei


    Many factors influence the chemical composition in electroslag remelting (ESR) steel, including atmosphere in crucible, melting rate, slag composition, deoxidation, and so on. Fluoride-based slag, which is exposed to liquid metal directly, influences the chemical composition of ESR ingots to a large extent. The present paper focuses on the effect of slag on the titanium, silicon, and aluminum contents in ingots based on the interaction of the slag and metal. In present work, superalloy of GH8825 and several slags containing different CaO contents have been employed for investigating the effect of slag on titanium, silicon, and aluminum contents in an electrical resistance furnace under argon atmosphere. Results indicate that the higher CaO content in slag has better capacity for avoiding loss of titanium caused by the reaction of titanium with silica in slag, especially in case of remelting superalloy with high titanium and low silicon content. The CaO has a great effect on the activities of TiO2, SiO2, and Al2O3. Thermodynamic analysis is applied to investigate the CaO behavior. Based on the ion and molecule coexistence theory of slag, activity model is established to calculate the activities of components containing titanium, silicon, and aluminum elements in a six-component slag consisting of CaO-CaF2-Al2O3-SiO2-TiO2-MgO. The components containing titanium, silicon, and aluminum in slag are mainly CaO·TiO2, 2CaO·SiO2, CaO·SiO2, CaO·Al2O3, and MgO·Al2O3. With the increase of CaO mass fraction in slag, the activity coefficient of SiO2 decreases significantly, whereas slightly change happens for Al2O3. As a result, the lg ({{γ_{{{{SiO}}2 }} } {/ {{{γ_{{{{SiO}}2 }} } {γ_{{{{TiO}}2 }} }}} {γ_{{{{TiO}}2 }} }}) decreases with increasing CaO content, which is better for preventing loss of titanium caused by the reaction of titanium with silica in slag. The slag with high CaO and appropriate TiO2 content is suitable for electroslag remelting of GH8825.

  6. The Effect of Oxygen Potential on the Sulfide Capacity for Slags Containing Multivalent Species

    Allertz, Carl; Selleby, Malin; Sichen, Du


    The dependence of sulfide capacity on the oxygen partial pressure for slags containing multivalent species was investigated experimentally using a slag containing vanadium oxide. Copper-slag equilibration experiments were carried out at 1873 K (1600 °C) in the approximate oxygen partial pressure range 10-15.4 to 10-9 atm. The sulfide capacity was found to be strongly dependent on the oxygen potential in this slag system, increasing with the oxygen partial pressure. The sulfide capacity changed by more than two orders of magnitude over the oxygen partial pressure range. The effect of changing oxygen partial pressure was found to be much greater than the effect of changing slag composition at a fixed oxygen partial pressure.

  7. Rapid Dissolution of Quicklime into Molten Slag by Internally Formed Gas

    Maruoka, Nobuhiro; Nogami, Hiroshi


    In steelmaking process, quicklime is used to produce CaO-based slag. Although rapid dissolution of quicklime is required for high-efficiency refining, it is known that the rate decreases when dicalcium silicate (C2S) layer forms around the quicklime by reacting with slag. The equation that driving force is the difference of CaO content between in slag and a liquid phase of slag saturated by C2S has been often used for estimating the dissolution rate of lime, in which this saturated value is thermodynamically determined. The authors, however, revealed that the quicklime used in actual operation showed much faster dissolving rate than that of completely calcined lime that is covered by C2S layer during dissolution into slag. This was caused by a gas formation due to a thermal decomposition of residual limestone existed in quicklime. In this study, the dissolution rate of quicklime with the gas formation is quantitatively investigated.

  8. Precipitation of metallic chromium during rapid cooling of Cr2O3 slags

    J. Burja


    Full Text Available The slag systems of CaO-SiO2- Cr2O3 and Al2O3-CaO-MgO-SiO2- Cr2O3 were analyzed. These slag systems occur in the production of stainless steel and are important from the process metallurgy point of view. Synthetic slag samples with different chromium oxide content were prepared and melted. The melted slag samples where then rapidly cooled on large steel plates, so that the high temperature microstructure was preserved. The samples were analyzed by scanning electron microscopy (SEM and X-ray diffraction (XRD. The precipitation of different chromium oxide phases was studied, but most importantly the precipitation of metallic chromium was observed. These findings help us interpret industrial slag samples.

  9. Cementing properties of steel slag activated by sodium silicates and sodium hydroxide

    Wen Ni; En Wang; Jianping Li; Han Sun


    Steel slag which is mainly composed of γ-CasSiO4 and other silicates or alumino-silicates is activated by sodium silicates and sodium hydroxide. The powders of such steel slag are usually inert to hydrate and subsequently have very low ability of cementing. But when sodium silicates and sodium hydroxide are used as activators the steel slag shows very good properties of cementing. When activated with NaOH solution the hardened slurry of the steel slag has a compressive strength of 11.13 MPa after being cured for 28 days. When activated with Na2SiO3 solution the samples after being cured for 28 days have an average compressive strength of 40.23 MPa. While the steel slag slurry which is only mixed with water has a compressive of 0.88 MPa after being cured for 28 days.

  10. Study on Mechanism of Reaction Between AOD Slag and Rebonded Magnesite—Chrome Brick

    ZHAOYuxi; HEXiaoping


    The influence of the composition of AOD slag on the corrosion of rebonded magnesite-chrome brick has been studied by analyzing the residual bricks at the tuyere zone of AOD .It indicates that the corrosion degree increased with the increase of the basicity of slag and decreased with the increase of the content of MgO ,Cr2O3 and Al2O3 in slag.And the addition of refractories to slag up to satura-tion could decrease the corrosion abiliy of sag.It is important to make a resonable slagmaking rule and ensure the percentage of MgO in slag more than 11wt% for pro-longing the service life of lining.

  11. Laboratory Investigation of Fatigue Characteristics of Asphalt Mixtures with Steel Slag Aggregates

    Hassan Ziari


    Full Text Available There are many steel-manufacturing factories in Iran. All of their byproducts, steel slag, are dumped randomly in open areas, causing many environmentally hazardous problems. This research is intended to study the effectiveness of using steel slag aggregate (SSA in improving the engineering properties, especially fatigue life of Asphalt Concrete (AC produced with steel slag. The research started by evaluating the physical properties of the steel slag aggregate. Then the 13 types of mixes which contain steel slag in portion of fine aggregates or in portion of coarse aggregates or in all portions of aggregates were tested. The effectiveness of the SSA was judged by the improvement in Marshall stability, indirect tensile strength, resilient modulus, and fatigue life of the AC samples. It was found that replacing the 50% of the limestone coarse or fine aggregate by SSA improved the mechanical properties of the AC mixes.

  12. Effect of Fine Steel Slag Powder on the Early Hydration Process of Portland Cement


    Hydration heat evolution, non-evaporative water, setting time and SEM tests were performed to investigate the effect of fine steel slag powder on the hydration process of Portland cement and its mechanism.The results show that the effect of fine steel slag powder on the hydration process of Portland cement is closely related to its chemical composition, mineral phases, fineness, etc.Fine steel slag powder retards the hydration of portland cement at early age.The major reason for this phenomenon is the relative high content of MgO , MnO2, P2 O5in steel slag, and MgO solid solved in C3 S contained in steel slag.

  13. Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

    Mao-chieh Chi


    Full Text Available The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.

  14. Verification of Steelmaking Slags Iron Content Final Technical Progress Report

    J.Y. Hwang


    The steel industry in the United States generates about 30 million tons of by-products each year, including 6 million tons of desulfurization and BOF/BOP slag. The recycling of BF (blast furnace) slag has made significant progress in past years with much of the material being utilized as construction aggregate and in cementitious applications. However, the recycling of desulfurization and BOF/BOP slags still faces many technical, economic, and environmental challenges. Previous efforts have focused on in-plant recycling of the by-products, achieving only limited success. As a result, large amounts of by-products of various qualities have been stockpiled at steel mills or disposed into landfills. After more than 50 years of stockpiling and landfilling, available mill site space has diminished and environmental constraints have increased. The prospect of conventionally landfilling of the material is a high cost option, a waste of true national resources, and an eternal material liability issue. The research effort has demonstrated that major inroads have been made in establishing the viability of recycling and reuse of the steelmaking slags. The research identified key components in the slags, developed technologies to separate the iron units and produce marketable products from the separation processes. Three products are generated from the technology developed in this research, including a high grade iron product containing about 90%Fe, a medium grade iron product containing about 60% Fe, and a low grade iron product containing less than 10% Fe. The high grade iron product contains primarily metallic iron and can be marketed as a replacement of pig iron or DRI (Direct Reduced Iron) for steel mills. The medium grade iron product contains both iron oxide and metallic iron and can be utilized as a substitute for the iron ore in the blast furnace. The low grade iron product is rich in calcium, magnesium and iron oxides and silicates. It has a sufficient lime value and

  15. Verification of Steelmaking Slags Iron Content Final Technical Progress Report

    J.Y. Hwang


    The steel industry in the United States generates about 30 million tons of by-products each year, including 6 million tons of desulfurization and BOF/BOP slag. The recycling of BF (blast furnace) slag has made significant progress in past years with much of the material being utilized as construction aggregate and in cementitious applications. However, the recycling of desulfurization and BOF/BOP slags still faces many technical, economic, and environmental challenges. Previous efforts have focused on in-plant recycling of the by-products, achieving only limited success. As a result, large amounts of by-products of various qualities have been stockpiled at steel mills or disposed into landfills. After more than 50 years of stockpiling and landfilling, available mill site space has diminished and environmental constraints have increased. The prospect of conventionally landfilling of the material is a high cost option, a waste of true national resources, and an eternal material liability issue. The research effort has demonstrated that major inroads have been made in establishing the viability of recycling and reuse of the steelmaking slags. The research identified key components in the slags, developed technologies to separate the iron units and produce marketable products from the separation processes. Three products are generated from the technology developed in this research, including a high grade iron product containing about 90%Fe, a medium grade iron product containing about 60% Fe, and a low grade iron product containing less than 10% Fe. The high grade iron product contains primarily metallic iron and can be marketed as a replacement of pig iron or DRI (Direct Reduced Iron) for steel mills. The medium grade iron product contains both iron oxide and metallic iron and can be utilized as a substitute for the iron ore in the blast furnace. The low grade iron product is rich in calcium, magnesium and iron oxides and silicates. It has a sufficient lime value and

  16. 慢性磷性颌骨骨髓炎的临床探讨%Clinical study of chronical phosphorus osteomyelitis of the jaw

    谢玲; 王卫红; 许彪; 朱谨; 夏斌


    目的 探讨慢性磷性颌骨骨髓炎的临床特点及其机理,为临床及黄磷职业病诊断提供依据.方法 对6例因黄磷中毒引起颌骨骨髓炎患者的临床资料进行回顾性分析.结果 6例患者中,上颌骨4例,下颌骨2例.2例下颌骨磷性骨髓炎患者诊断为职业病.结论 磷性颌骨骨髓炎不仅发生于下颌骨,也可发生于上颌骨.上颌骨也应作为黄磷作业的健康检查及职业病诊断参考.%Objective To investigate the clinical characteristics and mechanism of yellow phosphorus jaw osteomelitis so as to provide the basis for clinical diagnosis of this occupational disease. Methods Clinical data of six patients suffering from jaw osteomyelitis due to yellow phosphorus poisoning in their jaw were reviewed retrospectively. Results Among those cases four cases' disease occurred in maxillas,two in mandibles. Only two patients suffering from mandibular yellow phosphorus osteomelitis were diagnosed to contract occupational disease in the end. Conclusions Yellow phosphorus osteomyelitis occurs not only in the mandible but also in the maxilla. With regard to yellow phosphorus workers,the maxillas should not been ruled out when health inspection is carried out.

  17. Study on Behaviour of Concrete Mix Replaceing Fine Aggregate With Steel Slag At Different Properties

    P.Sateesh Kumar


    Full Text Available This paper aims to study experimentally, the effect of partial replacement of fine aggregate by steel slag (ss, on the various strength and durability properties of concrete by using the mix designs .the optimum percentage of replacement of fine aggregate by steel slag is found. Workability of concrete gradually decreases, as the percentage of replacement increases which is found using slump test. Compressive strength, tensile strength, flexural strength and durability tests such as acid resistant’s, using HCL,H2SO4 and rapid chloride penetration, are experimentally investigated. The results indicate that for conventional concrete, partial replacement of concrete by steel slag improves the compressive, tensile, flexural strength. The mass loss in cubes after immersion in acids is found to be very low. Deflection in the RCC beams gradually increases, as the load on the beam increases, for the replacement. The degree of fluoride ion penetrability is assessed based on the limits given in ASTM C 1202. The viability of use of steel slag in concrete is found. Waste management is one of the most common and challenging problems in the world. The steel making industry has generated substantially solid waste. Steel slag is a residue obtained in steel making operation. This paper deals with the implementation of steel slag as an effective replacement for sand. Steel slag ,which is consider as the solid waste pollutant, can be used for road construction ,clinker raw materials, filling materials etc. In this work, steel slag used as replacement for sand, which is also major component concrete mixture. This method can be implement for producing hallow blocks, solid blocks, paver blocks, concrete structures etc. Accordingly, advantages can be achieved by using steel slag instead of natural aggregates this will also encourage other researchers to find another field of using steel slag.

  18. Evaluation of copper slag to catalyze advanced oxidation processes for the removal of phenol in water

    Huanosta-Gutierrez, T. [Instituto de Ingenieria, Coordinacion de Ingenieria Ambiental, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan 04510, Mexico, D.F. (Mexico); Dantas, Renato F., E-mail: [Departament d' Enginyeria Quimica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Ramirez-Zamora, R.M. [Instituto de Ingenieria, Coordinacion de Ingenieria Ambiental, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan 04510, Mexico, D.F. (Mexico); Esplugas, S. [Departament d' Enginyeria Quimica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)


    Highlights: Black-Right-Pointing-Pointer We evaluate the use of an industrial residue (copper slag) as catalyst in water treatment. Black-Right-Pointing-Pointer The copper slag was effective to remove organic pollutants (phenol) from water. Black-Right-Pointing-Pointer During experimentation, Cu and Fe leaching were not higher than the acceptable levels. Black-Right-Pointing-Pointer Slag/H{sub 2}O{sub 2}/UV and slag/H{sub 2}O{sub 2} treatments promoted biodegradability increment of the contaminated water. Black-Right-Pointing-Pointer The control of the reaction time would minimize the environmental impact of the produced effluents in terms of acute toxicity. - Abstract: The aim of this work was to evaluate the use of copper slag to catalyze phenol degradation in water by advanced oxidation processes (AOPs). Copper slag was tested in combination with H{sub 2}O{sub 2} (slag/H{sub 2}O{sub 2}) and H{sub 2}O{sub 2}/UV (slag/H{sub 2}O{sub 2}/UV). The studied methods promoted the complete photocatalytic degradation of phenol. Besides, they were able to reduce about 50% the TOC content in the samples. Slag/H{sub 2}O{sub 2}/UV and slag/H{sub 2}O{sub 2} treatments have favored biodegradability increment along the reaction time. Nevertheless, the irradiated method achieved higher values of the biodegradability indicator (BOD{sub 5}/TOC). The toxicity assessment indicated the formation of more toxic compounds in both treatments. However, the control of the reaction time would minimize the environmental impact of the effluents.

  19. Evaluation of Secondary Steelmaking Slags and Their Relation with Steel Cleanliness

    da Rocha, Vinicius Cardoso; Pereira, Julio A. M.; Yoshioka, Ayumi; Bielefeldt, Wagner V.; Vilela, Antônio C. F.


    Based on data provided from an industrial plant and FactSage commercial software use, a study of secondary refining slags and inclusion cleanliness was performed. Six heats of two slag series, namely, A and B, with average chemical composition (wt pct) of 43.00CaO-25.90SiO2-12.96Al2O3-18.13MgO for series A and 49.98CaO-23.88SiO2-10.11Al2O3-11.99MgO-4.03CaF2 for series B, were used for the study. Both series used DIN 38MnS6 modified steel. The effective viscosity, solid fraction, composition of the liquid fraction, and slag saturation degree in MgO (calculated through thermodynamic software) were related to the experimental results obtained for the inclusion cleanliness. The B slags showed lower effective viscosity than the A slags, due to their high liquid fraction. Regarding the capacity of slags in the inclusion removal, slag B5 resulted in the lowest inclusion density and was considered as the best choice among the slags studied. The inclusion species formed using B slags are constituted especially of CaO-Al2O3-SiO2 and MgO-Al2O3 and are Al2O3 rich. The presence of sulfide-type inclusions (AlMnS and CaS) were more pronounced among A slags.

  20. CO2 sequestration utilizing basic-oxygen furnace slag: Controlling factors, reaction mechanisms and V-Cr concerns.

    Su, Tung-Hsin; Yang, Huai-Jen; Shau, Yen-Hong; Takazawa, Eiichi; Lee, Yu-Chen


    Basic-oxygen furnace slag (BOF-slag) contains >35% CaO, a potential component for CO2 sequestration. In this study, slag-water-CO2 reaction experiments were conducted with the longest reaction duration extending to 96hr under high CO2 pressures of 100-300kg/cm(2) to optimize BOF-slag carbonation conditions, to address carbonation mechanisms, and to evaluate the extents of V and Cr release from slag carbonation. The slag carbonation degree generally reached the maximum values after 24hr slag-water-CO2 reaction and was controlled by slag particle size and reaction temperature. The maximum carbonation degree of 71% was produced from the experiment using fine slag of ≤0.5mm under 100°C and a CO2 pressure of 250kg/cm(2) with a water/slag ratio of 5. Vanadium release from the slag to water was significantly enhanced (generally >2 orders) by slag carbonation. In contrast, slag carbonation did not promote chromium release until the reaction duration exceeded 24hr. However, the water chromium content was generally at least an order lower than the vanadium concentration, which decreased when the reaction duration exceeded 24hr. Therefore, long reaction durations of 48-96hr are proposed to reduce environmental impacts while keeping high carbonation degrees. Mineral textures and water compositions indicated that Mg-wüstite, in addition to CaO-containing minerals, can also be carbonated. Consequently, the conventional expression that only considered carbonation of the CaO-containing minerals undervalued the CO2 sequestration capability of the BOF-slag by ~20%. Therefore, the BOF-slag is a better CO2 storage medium than that previously recognized.

  1. Phosphorus Adsorption Properties of Different Substrates in Constructed Wetland%不同人工湿地基质对磷的吸附性能研究

    陈丽丽; 赵同科; 张成军; 李鹏; 李新荣; 董若征


    通过基质磷素吸附动力学、等温吸附以及基质饱和吸附后磷素解吸实验,研究陶瓷滤料、红泥、水洗砂、炉渣4种人工湿地基质净化磷素的效果,评价其基质磷素饱和吸附后磷素解吸可能造成的二次污染风险.结果表明,在溶液磷(P)浓度为5~150 mg·L-1条件下,Langmuir和Freundlich等温吸附方程均能很好地描述陶瓷滤料和红泥两种基质的磷素吸附过程,陶瓷滤料用Langmuir方程比Freundlich方程的拟合程度更好,红泥则相反.4种基质对磷素的吸附量顺序依次为红泥>陶瓷滤料>炉渣>水洗砂.从磷素的解吸率来看,4种基质释磷顺序依次为炉渣>水洗砂>陶瓷滤料>红泥,水洗砂和炉渣吸附磷素后的解吸率较高,其他两种基质磷素解吸的比例很低.综合评价,陶瓷滤料更适合作为人工湿地污水除磷的基质.%Constructed wetlands are widely used to purify wastewater in some developing countries. As filter substrates in such wetland, these substrates play vital role on removal of pollutants from wastewater. Selecting suitable substrates is one of the effective ways to improve the performance of constructed wetland on treating wastewater. The purification effect of the four different substrates( ceramic filter, red mud, water washing sand and slag)for phosphorus in a constructed wetland was studied by substrate phosphorus adsorption dynamics, isothermal adsorption and phosphorus desorption after being saturated adsorption. The possible secondary pollution risk caused by phosphorus desorption after being saturated adsorption by substrates was also evaluated. The results showed that both Langmuir and Freundlich isothermal adsorption equation could well describe the phosphate adsorption process of ceramic filter and red mud substrates under the conditions of phosphorus ( P) concentration for 5~150 mg · L-1. For the ceramic filter, the regression level used with Langmuir equation was better than

  2. Fabrication of slag-glass composite with controlled porosity

    Ranko Adziski


    Full Text Available The preparation and performance of porous ceramics made from waste materials were investigated. Slag from thermal electrical plant Kakanj (Bosnia and Herzegovina with defined granulations: (0.500÷0.250 mm; (0.250÷0.125 mm; (0.125÷0.063 mm; (0.063÷0.045 mm and 20/10 wt.% of the waste TV screen glass with a granulation <0.063 mm were used for obtaining slag-glass composites with controlled porosity. The one produced from the slag powder fraction (0.125÷0.063 mm and 20 wt.% TV screen glass, sintered at 950°C/2h, was considered as the optimal. This system possesses open porosity of 26.8±1.0%, and interconnected pores with the size of 250–400 μm. The values of E-modulus and bending strength of this composite were 10.6±0.6 GPa and 45.7±0.7 MPa, respectively. The coefficient of thermal expansion was 8.47·10-6/°C. The mass loss in 0.1M HCl solution after 30 days was 1.2 wt.%. The permeability and the form coefficient of the porous composite were K0=0.12 Da and C0=4.53·105 m-1, respectively. The porous composite shows great potential to be used as filters, diffusers for water aeration, dust collectors, acoustic absorbers, etc.

  3. The Scientific Challenges of Yellow River Study

    Liu Xiaoyan; Sun Yangbo


    @@ The Yellow River is famous for its complex and unique physical conditions which give great challenges to the river management. Based on the study and analysis of the existing problems and research progress, this paper indicated that the most significant challenges of Yellow River studies are: long term hydrological and morphological changes; the optimized hydrology and sediment conditions to maintain the healthy life of the River; and simulation of Yellow River through mathematical model and physical models.

  4. Sulfide capacities of MnO-SiO2 slags

    Reddy, Ramana G.; Blander, Milton


    Sulfide capacities of binary MnO-SiO2 slags at 1773 and 1923 K were calculated thermodynamically. Only known data, such as the standard free energy of formation of MnO and MnS and activities of MnO in the melt, are used in making calculations based on fundamental concepts. Excellent agreement is found between our calculations and published experimental data. Correlations of sulfide capacities, based on optical basicity using Pauling electronegativities or empirically deduced optical basicities, differ from the experimental data in both magnitude and concentration dependence. Our method provides useful predictions of sulfide capacities a priori.

  5. Computer recognition of slag property diagrams in ternary systems

    Jinxiong Lu; Li Wang; Jiongming Zhang; Xinhua Wang


    In order to take data information from the slag property diagram in a ternary system automatically and actually, a picture recognition and drawing software has been developed by Visual Basic 6.0 based on the image coding principle of computer system and the graphics programming method of VB. This software can transform the ternary system isopleth diagram from bitmap format to data file and establish a corresponding database which can be applied to rapidly retrieve a mass of data and make correlative thermodynamics or kinetics calculation. Besides, it still has the function of drawing the ternary system diagram which can draw different kinds of property parameters in the same diagram.


    Michał Łach


    Full Text Available The work concerns the possibility of the use of secondary waste from waste incineration processes for the production of zeolites. The study used fly ash and slag from national waste incineration plants. The test materials were subjected to hydrothermal alkaline activation in aqueous solution of sodium hydroxide, the molar concentrations of the various variants. The research revealed the usefulness of this type of material for the synthesis of zeolites –obtained sodalite. Presents the results of analyzes of the SEM / EDS and XRD for the most efficient synthesis processes.

  7. A Model for Dissolution of Lime in Steelmaking Slags

    Sarkar, Rahul; Roy, Ushasi; Ghosh, Dinabandhu


    In a previous study by Sarkar et al. (Metall. Mater. Trans. B 46B:961 2015), a dynamic model of the LD steelmaking was developed. The prediction of the previous model (Sarkar et al. in Metall. Mater. Trans. B 46B:961 2015) for the bath (metal) composition matched well with the plant data (Cicutti et al. in Proceedings of 6th International Conference on Molten Slags, Fluxes and Salts, Stockholm City, 2000). However, with respect to the slag composition, the prediction was not satisfactory. The current study aims to improve upon the previous model Sarkar et al. (Metall. Mater. Trans. B 46B:961 2015) by incorporating a lime dissolution submodel into the earlier one. From the industrial point of view, the understanding of the lime dissolution kinetics is important to meet the ever-increasing demand of producing low-P steel at a low basicity. In the current study, three-step kinetics for the lime dissolution is hypothesized on the assumption that a solid layer of 2CaO·SiO2 should form around the unreacted core of the lime. From the available experimental data, it seems improbable that the observed kinetics should be controlled singly by any one kinetic step. Accordingly, a general, mixed control model has been proposed to calculate the dissolution rate of the lime under varying slag compositions and temperatures. First, the rate equation for each of the three rate-controlling steps has been derived, for three different lime geometries. Next, the rate equation for the mixed control kinetics has been derived and solved to find the dissolution rate. The model predictions have been validated by means of the experimental data available in the literature. In addition, the effects of the process conditions on the dissolution rate have been studied, and compared with the experimental results wherever possible. Incorporation of this submodel into the earlier global model (Sarkar et al. in Metall. Mater. Trans. B 46B:961 2015) enables the prediction of the lime dissolution rate

  8. Quantification and Modelling of Fugitive Dust Emissions From Nickel Slag

    Sanderson, R. S.; McKenna Neuman, C.


    Mining and smelting operations in Northern Ontario, and indeed worldwide, introduce a number of unique sources of fugitive dust and other aerosol pollutants into the surrounding environment from smokestacks, tailings, and slag dumps exposed to wind erosion. Fugitive dust represents a potential health hazard, and as such, mining companies are required to maintain inventories of dust emissions associated with their operations. The purpose of this study was to fully characterize the wind-induced fugitive dust emission rates of nickel slag collected from a slag dump at a smelting facility in Northern Ontario, as dependent on wind speed, surface roughness, duration of weathering, effects of mechanical disturbance, and exposure to rain. PM10 flux rates were measured through combined field monitoring and wind tunnel simulation. In both settings, airborne dust concentrations downwind of the source were measured using four vertically distributed DustTrak aerosol monitors. Wind speed was measured in the wind tunnel using a micro-pitot tube mounted on a programmable traversing slide, and in the field, using five vertically distributed cup anemometers mounted on a mast. The profiles of PM10 and wind speed were used to compute the vertical emission rate (Fv) using a finite difference method. The PM10 emission rates simulated in the laboratory were found to directly overlap those measured on site at the smelting facility over a range of wind speeds, suggesting that Fv values measured in wind tunnel simulations can be used in dispersion modelling with a reasonable degree of confidence. Although showing a strong positive correlation with wind speed, PM10 emissions from nickel slag were found to demonstrate an exponential, temporal decay immediately following any form of mechanical disturbance that resulted in exposure of the silt fraction of the material. Winnowing of this fraction left behind an armoured surface of coarse, non-erodible clasts. It was further determined that

  9. The Relevance of Phosphorus and Iron Chemistry to the Recovery of Phosphorus from Wastewater: A Review.

    Wilfert, Philipp; Kumar, Prashanth Suresh; Korving, Leon; Witkamp, Geert-Jan; van Loosdrecht, Mark C M


    The addition of iron is a convenient way for removing phosphorus from wastewater, but this is often considered to limit phosphorus recovery. Struvite precipitation is currently used to recover phosphorus, and this approach has attracted much interest. However, it requires the use of enhanced biological phosphorus removal (EBPR). EBPR is not yet widely applied and the recovery potential is low. Other phosphorus recovery methods, including sludge application to agricultural land or recovering phosphorus from sludge ash, also have limitations. Energy-producing wastewater treatment plants increasingly rely on phosphorus removal using iron, but the problem (as in current processes) is the subsequent recovery of phosphorus from the iron. In contrast, phosphorus is efficiently mobilized from iron by natural processes in sediments and soils. Iron-phosphorus chemistry is diverse, and many parameters influence the binding and release of phosphorus, including redox conditions, pH, presence of organic substances, and particle morphology. We suggest that the current poor understanding of iron and phosphorus chemistry in wastewater systems is preventing processes being developed to recover phosphorus from iron-phosphorus rich wastes like municipal wastewater sludge. Parameters that affect phosphorus recovery are reviewed here, and methods are suggested for manipulating iron-phosphorus chemistry in wastewater treatment processes to allow phosphorus to be recovered.

  10. Selective enrichment of TiO2 and precipitation behavior of perovskite phase in titania bearing slag

    WANG Ming-yu; ZHANG Lin-nan; ZHANG Li; SUI Zhi-tong; TU Gan-feng


    The effects of additive agents and growth behavior of perovskite phase as well as temperature change of slag at semi industry scale test were studied. The results show that the increase of steel slag does good to titania enrichment, however, it isn't useful for the growth and coarsening of the perovskite phase. The additive Si-Fe powder can promote titania enrichment and make perovskite phase grow up easily. While air is blown into the molten slag, the reduced components in slag are oxidized and the released heat raises the temperature of slag.

  11. Structure and properties of the slags of continuous converting of copper nickel-containing mattes and concentrates: II. Effect of the SiO2/CaO ratio on the structure and liquidus temperature of the slags

    Pigarev, S. P.; Tsymbulov, L. B.; Selivanov, E. N.; Chumarev, V. M.


    The structure and liquidus temperature of the SiO2-CaO-Al2O3-FeO x -Cu2O-NiO slags that form during continuous converting of copper mattes and concentrates into blister copper are analyzed. The slag melt compositions are varied over a wide SiO2/CaO range. The slags are studied by X-ray diffraction, scanning electron microscopy, and electron-probe microanalysis. The liquidus temperature of the slags is determined by differential thermal analysis. It is found that, depending on the SiO2/CaO ratio, the structure and liquidus temperature of the slags change and the forms of copper in a slag also change. The SiO2/CaO range in a slag is recommended for the process of continuous converting of a copper nickel-containing sulfide raw materials.

  12. Titanium exposure and yellow nail syndrome

    Ali Ataya


    Full Text Available Yellow nail syndrome is a rare disease of unclear etiology. We describe a patient who develops yellow nail syndrome, with primary nail and sinus manifestations, shortly after amalgam dental implants. A study of the patient's nail shedding showed elevated nail titanium levels. The patient had her dental implants removed and had complete resolution of her sinus symptoms with no change in her nail findings. Since the patient's nail findings did not resolve we do not believe titanium exposure is a cause of her yellow nail syndrome but perhaps a possible relationship exists between titanium exposure and yellow nail syndrome that requires further studies.

  13. Isolation of yellow catfish β-actin promoter and generation of transgenic yellow catfish expressing enhanced yellow fluorescent protein.

    Ge, Jiachun; Dong, Zhangji; Li, Jingyun; Xu, Zhiqiang; Song, Wei; Bao, Jie; Liang, Dong; Li, Junbo; Li, Kui; Jia, Wenshuang; Zhao, Muzi; Cai, Yongxiang; Yang, Jiaxin; Pan, Jianlin; Zhao, Qingshun


    Yellow catfish (Pelteobagrus fulvidraco Richardson) is one of the most important freshwater farmed species in China. However, its small size and slow growth rate limit its commercial value. Because genetic engineering has been a powerful tool to develop and improve fish traits for aquaculture, we performed transgenic research on yellow catfish in order to increase its size and growth rate. Performing PCR with degenerate primers, we cloned a genomic fragment comprising 5'-flanking sequence upstream of the initiation codon of β-actin gene in yellow catfish. The sequence is 1,017 bp long, containing the core sequence of proximal promoter including CAAT box, CArG motif and TATA box. Microinjecting the transgene construct Tg(beta-actin:eYFP) of the proximal promoter fused to enhanced yellow fluorescent protein (eYFP) reporter gene into zebrafish and yellow catfish embryos, we found the promoter could drive the reporter to express transiently in both embryos at early development. Screening the offspring of five transgenic zebrafish founders developed from the embryos microinjected with Tg(ycbeta-actin:mCherry) or 19 yellow catfish founders developed from the embryos microinjected with Tg(beta-actin:eYFP), we obtained three lines of transgenic zebrafish and one transgenic yellow catfish, respectively. Analyzing the expression patterns of the reporter genes in transgenic zebrafish (Tg(ycbeta-actin:mCherry)nju8/+) and transgenic yellow catfish (Tg(beta-actin:eYFP)nju11/+), we found the reporters were broadly expressed in both animals. In summary, we have established a platform to make transgenic yellow catfish using the proximal promoter of its own β-actin gene. The results will help us to create transgenic yellow catfish using "all yellow catfish" transgene constructs.

  14. Mechanical and leaching behaviour of slag-cement and lime-activated slag stabilised/solidified contaminated soil.

    Kogbara, Reginald B; Al-Tabbaa, Abir


    Stabilisation/solidification (S/S) is an effective technique for reducing the leachability of contaminants in soils. Very few studies have investigated the use of ground granulated blast furnace slag (GGBS) for S/S treatment of contaminated soils, although it has been shown to be effective in ground improvement. This study sought to investigate the potential of GGBS activated by cement and lime for S/S treatment of a mixed contaminated soil. A sandy soil spiked with 3000mg/kg each of a cocktail of heavy metals (Cd, Ni, Zn, Cu and Pb) and 10,000mg/kg of diesel was treated with binder blends of one part hydrated lime to four parts GGBS (lime-slag), and one part cement to nine parts GGBS (slag-cement). Three binder dosages, 5, 10 and 20% (m/m) were used and contaminated soil-cement samples were compacted to their optimum water contents. The effectiveness of the treatment was assessed using unconfined compressive strength (UCS), permeability and acid neutralisation capacity (ANC) tests with determination of contaminant leachability at the different acid additions. UCS values of up to 800kPa were recorded at 28days. The lowest coefficient of permeability recorded was 5×10(-9)m/s. With up to 20% binder dosage, the leachability of the contaminants was reduced to meet relevant environmental quality standards and landfill waste acceptance criteria. The pH-dependent leachability of the metals decreased over time. The results show that GGBS activated by cement and lime would be effective in reducing the leachability of contaminants in contaminated soils. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Effect of Slag Composition on the Distribution Behavior of Pb between FetO-SiO2 (-CaO, Al2O3) Slag and Molten Copper

    Heo, Jung Ho; Park, Soo-Sang; Park, Joo Hyun


    The distribution behavior of Pb between molten copper and FetO-SiO2 (-CaO, Al2O3) slags was investigated at 1473 K (1200 °C) and p_{{{{O}}2 }} = 10^{ - 10} {{atm}} in view of the reaction mechanism of Pb dissolution into the slag. Furthermore, the lead capacity of the slag was estimated from the experimental results. The distribution ratio of Pb ( L Pb) decreases with increasing CaO content ( 6 mass pct) irrespective of Fe/SiO2 ratio (1.4 to 1.7). However, the addition of alumina into a slag with Fe/SiO2 = 1.5 linearly decreases the L Pb, whereas a minimum value is observed at about 4 mass pct Al2O3 at Fe/SiO2 = 1.3. The log L Pb continuously decreases with increasing Fe/SiO2 ratio, and the addition of Al2O3 (5 to 15 mass pct) into the silica-saturated iron silicate slag (Fe/SiO2 < 1.0) yields the highest Pb distribution ratio. This is mainly due to a decrease in the FeO activity even at silica saturation. The log L Pb linearly decreases by increasing the log (Fe3+/Fe2+) value. The Pb distribution ratio increases and the excess free energy of PbO decreases with increasing Cu2O content in the slag. However, from the viewpoint of copper loss into the slag, the silica-saturated system containing small amounts of alumina is strongly recommended to stabilize PbO in the slag phase at a low Cu2O content. The lead capacity was defined in the current study and shows a linear correlation with the activity of FeO in a logarithmic scale, indicating that the concept of lead capacity is a good measure of absorption ability of Pb in iron silicate slags, and the activity of FeO can be a good basicity index in iron silicate slag.

  16. Effects of Air-Drying on the Inorganic Phosphorus Forms in Soils

    FENG Ke; TANG Yan; WANG Xiao-li; LU Hai-ming; ZHAO Hai-tao


    After 90 day's cultivation of five different plants (rye grass, lupin, buckwheat, rape and amaranth) in three soils (Yellow brown soil, Paddy soil and Red soil), fresh soil samples were collected and inorganic phosphorus (Pi) fractions were measured before and after air-drying. The results clearly indicated that the total Pi and their composition differed significantly among soil types. The air-drying process increased the total Pi in yellow brown soil and in paddy soil, while decreased that in red soil. The total Pi could vary to 70% of that before air-drying. The Pi forms in different soils changed to different extent after air-drying. As to yellow brown soil, Al-P decreased, while O-P and Ca-P increased; as to paddy soil, Al-P and Ca-P increased, while Fe-P and O-P remained; as to red soil, Al-P and Fe-P increased, Ca-P remained and O-P reduced obviously. Growth of different plants in soils had effects on Pi forms during the process of air-drying. Therefore, for chemical study of soil phosphorus, application of fresh soil samples can provide more reliable results.

  17. Denitrifying woodchip bioreactor and phosphorus filter pairing to minimize pollution swapping

    Christianson, Laura E.; Lepine, Christine; Sibrell, Philip; Penn, Chad J.; Summerfelt, Steven T.


    Pairing denitrifying woodchip bioreactors and phosphorus-sorbing filters provides a unique, engineered approach for dual nutrient removal from waters impaired with both nitrogen (N) and phosphorus (P). This column study aimed to test placement of two P-filter media (acid mine drainage treatment residuals and steel slag) relative to a denitrifying system to maximize N and P removal and minimize pollution swapping under varying flow conditions (i.e., woodchip column hydraulic retention times (HRTs) of 7.2, 18, and 51 h; P-filter HRTs of 7.6–59 min). Woodchip denitrification columns were placed either upstream or downstream of P-filters filled with either medium. The configuration with woodchip denitrifying systems placed upstream of the P-filters generally provided optimized dissolved P removal efficiencies and removal rates. The P-filters placed upstream of the woodchip columns exhibited better P removal than downstream-placed P-filters only under overly long (i.e., N-limited) retention times when highly reduced effluent exited the woodchip bioreactors. The paired configurations using mine drainage residuals provided significantly greater P removal than the steel slag P-filters (e.g., 25–133 versus 8.8–48 g P removed m−3 filter media d−1, respectively), but there were no significant differences in N removal between treatments (removal rates: 8.0–18 g N removed m−3 woodchips d−1; N removal efficiencies: 18–95% across all HRTs). The range of HRTs tested here resulted in various undesirable pollution swapping by-products from the denitrifying bioreactors: nitrite production when nitrate removal was not complete and sulfate reduction, chemical oxygen demand production and decreased pH during overly long retention times. The downstream P-filter placement provided a polishing step for removal of chemical oxygen demand and nitrite.

  18. Natural Phosphorus Sources for the Pacific Northwest

    U.S. Geological Survey, Department of the Interior — Phosphorus is a naturally occurring element found in all rocks; the amount varies by the type of rock. The amount of phosphorus in sediments is expected to be...

  19. Economic feasibility study for phosphorus recovery processes.

    Molinos-Senante, María; Hernández-Sancho, Francesc; Sala-Garrido, Ramón; Garrido-Baserba, Manel


    Phosphorus recovery from wastewater has become a necessity for sustainable development because phosphorus is a non-renewable essential resource, and its discharge into the environment causes serious negative impacts. There are no economic incentives for the implementation of phosphorus recovery technologies because the selling price of rock phosphate is lower than phosphorus recovered from sewage. The methodologies used to determine the feasibility of such projects are usually focused on internal costs without considering environmental externalities. This article shows a methodology to assess the economic feasibility of wastewater phosphorus recovery projects that takes into account internal and external impacts. The shadow price of phosphorus is estimated using the directional distance function to measure the environmental benefits obtained by preventing the discharge of phosphorus into the environment. The economic feasibility analysis taking into account the environmental benefits shows that the phosphorus recovery is viable not only from sustainable development but also from an economic point of view.

  20. Edge phonons in black phosphorus

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.


    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  1. Phosphorus Flamethrower: A Demonstration Using Red and White Allotropes of Phosphorus

    Golden, Melissa L.; Person, Eric C.; Bejar, Miriam; Golden, Donnie R.; Powell, Jonathan M.


    A demonstration was created to display the unique behavior of a familiar element, phosphorus, and to make chemistry more accessible to the introductory student. The common allotropes of phosphorus and their reactivity are discussed. In this demonstration, the white allotrope of phosphorus is synthesized from the red phosphorus obtained from a…

  2. Soil Stabilisation Using Ground Granulated Blast Furnace Slag

    Ashish Kumar Pathak


    Full Text Available Stabilisation is a broad sense for the various methods employed and modifying the properties of a soil to improve its engineering performance and used for a variety of engineering works. In today‟s day soil stabilisation is the major problem for civil engineers, either for construction of road and also for increasing the strength or stability of soil and reduces the construction cost. In this thesis the soil are stabilised by ground granulated blast furnace slag (GGBS and this material is obtained from the blast furnace of cement plant, which is the byproduct of iron (from ACC plant, sindri. It is generally obtained in three shaped one is air cooled, foamed shaped and another is in granulated shaped. The use of by-product materials for stabilisation has environmental and economic benefits. Ground granulated blast furnace slag (GGBS material is used in the current work to stabilise soil (clay. The main objectives of this research were to investigate the effect of GGBS on the engineering property (optimum moisture content and maximum dry density, plastic limit, liquid limit, compaction, unconfined compressive strength, triaxial and California bearing ratio test of the soil and determine the engineering properties of the stabilised.

  3. Carbothermic Reduction of Titanium-Bearing Blast Furnace Slag

    Zhen, Yu-Lan; Zhang, Guo-Hua; Chou, Kuo-Chih


    The carbothermic reduction experiments were carried out for titanium-bearing blast furnace slag in Panzhihua Iron and Steel Company in argon atmosphere at high temperatures. The effects of reduction temperature, isothermal treatment time and carbon content on the formation of TiC were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD pattern results showed that MgAl2O4 phase disappeared and the main phase of the reduced sample was TiC when the reduction temperature was higher than 1,773 K. The SEM pictures showed that the reduction rate of the titanium-bearing blast furnace slag could be increased by enhancing the temperature and the C content (carbon ratio ≤1.0). Furthermore, it was also found that TiC had the tendency of concentrating around the iron. The effects of additives such as Fe and CaCl2 on the formation of TiC were also studied in the present study.

  4. Optimization for blast furnace slag dry cooling granulation device

    Dazhan, Sheng; Yali, Wang; Ruiyun, Wang; Suping, Cui; Xiaoyu, Ma


    Since the large accumulation amount of blast furnace slag (BFS) with recycling value, it has become a hot topic for recovery utilization. Compared with the existing various BFS granulation process, the dry granulation process can promote the use of blast furnace granulated slag as cement substitute and concrete admixtures. Our research group developed a novel dry cooling granulation experiment device to treat BFS. However, there are still some problems to be solved. The purpose of this research is to improve the cooling and granulation efficiency of the existing dry type cooling equipment. This topic uses the FLUENT simulation software to study the impact of the number of air inlet on the cooling effect of the device. The simulation result is that the device possessing eight air inlets can increase the number of hot and cold gas exchanged, resulting in a better cooling effect. According to the power consumption, LCA analysis was carried out on the cooling granulation process. The results show that the device equipped eight air inlets not only improved the original equipment cooling granulation effect, but also increased resource utilization ratio, realized energy-saving and emission reduction.

  5. Titania preparation from soda roasted slag using sulfuric acid solution

    El-Sayed A. Manaa


    Full Text Available This work deals with treatment of the sodium titanate cake results from roasted titania slag using 60% sulfuric acid solution. The working sample produced by roasting titania slag with NaCO3 at 850 °C. After roasting V and Cr species as impurities in the roasted sample are converted to water soluble species as NaVO3 and Na2CrO4 before acid treatment however, the insoluble sodium titanate products (NaFeTiO4, Na8Ti5O14, Na6Ti2O7 and Na2TiO4 are then subjected to H2SO4 acid dissolution. The produced sulfate solution is subjected to hydrolysis step in presence of oxalic acid as a reducing agent. The hydrolyzed precipitate after filtration and washing with H2SO4 solution and warm water is dried at 100 °C and calcinated at 850 °C to prepare high pure TiO2 (99.8% besides removing ferrous sulfate (FeSO4 as a byproduct from the sulfate solution.

  6. Performance of steel-making slag concrete reinforced with fibers

    Ortega-López Vanesa


    Full Text Available In this research, the possibility of making concrete reinforced with fibers and manufactured with recycled aggregates from carbon steel production was explored. Electric arc furnace slag (EAFS was used as coarse and medium aggregate, and part of the sand sizes. Metallic and synthetic fibers were added in different amounts. Initially, the properties of EAFS and their suitability to be used in the manufacture fiber reinforced concrete were analysed. Then, a series of fiber reinforced concrete mixtures were developed incorporating EAFS, and they were compared with the reference mixtures, made with conventional components plus fibers and made with EAFS without fibers. A series of tests were performed, including concepts such as consistency, compressive strength, flexural strength, splitting tensile strength, resistance to water penetration or toughness. The results show that it is possible to make a suitable steel-slag concrete reinforced with fibers, complying with the standard requirements for it use in pavements and slab, and improving their proprieties respect to the control mixtures.

  7. Novel sintered ceramic materials incorporated with EAF carbon steel slag

    Karayannis, V.; Ntampegliotis, K.; Lamprakopoulos, S.; Papapolymerou, G.; Spiliotis, X.


    In the present research, novel sintered clay-based ceramic materials containing electric arc furnace carbon steel slag (EAFC) as a useful admixture were developed and characterized. The environmentally safe management of steel industry waste by-products and their valorization as secondary resources into value-added materials towards circular economy have attracted much attention in the last years. EAF Carbon steel slag in particular, is generated during the manufacture of carbon steel. It is a solid residue mainly composed of rich-in- Fe, Ca and Si compounds. The experimental results show that the beneficial incorporation of lower percentages of EAFC up to 6%wt. into ceramics sintered at 950 °C is attained without significant variations in sintering behavior and physico-mechanical properties. Further heating up to 1100 °C strongly enhances the densification of the ceramic microstructures, thus reducing the porosity and strengthening their mechanical performance. On the other side, in terms of thermal insulation behavior as well as energy consumption savings and production cost alleviation, the optimum sintering temperature appears to be 950 °C.

  8. A Proposal for a Novel Method to Measure the Diffusivity of Species in Slag

    Muhmood, Luckman; Viswanathan, Nurni Neelakantan; Seetharaman, Seshadri


    The rate of reactions involved in steel-refining operations largely depend on the transport of species through the slag or metal phase at steel refining temperatures; the intrinsic reaction rates are expected to be high. Therefore, the study of diffusivity of species in slag is of great importance. The present work proposes a new methodology, in which experiments can be designed to determine the diffusivity of species in liquid slag. In this article, a mathematical description for the methodology is formulated and subsequently solved using numerical methods. This exercise will help in identifying appropriate bounds for experimental parameters for a desired accuracy. The proposed methodology is generic for any species in the liquid slag phase. However, diffusion of sulfur through slag has been illustrated as a case study. The order of magnitude for the diffusion coefficient for sulfur was taken from the classic works of Saito and Kawai, the sulfide capacity and sulfur partition ratio were retrieved from the works of Taniguchi et al., and the slag density was retrieved from earlier experimental results of the present authors. The slag density was obtained from earlier experimental results from the present group. The Henrian activity coefficients were retrieved from literature. Subsequent to the present work, the design of experiments and measurements carried out using the proposed methodology and the results obtained are presented as the second article on this subject.

  9. Effect of electric arc furnace slag on growth and physiology of maize (Zea mays L.).

    Radić, Sandra; Crnojević, Helena; Sandev, Dubravka; Jelić, Sonja; Sedlar, Zorana; Glavaš, Katarina; Pevalek-Kozlina, Branka


    Basic slag, used in this study as a potential source of certain nutrients, is a byproduct of the production of steel in electric arc furnace (EAF). A pot experiment with two nutrient-poor substrates was conducted to investigate to compare the effect of EAF steel slag and fertilizers NPK + F e on growth and availability of specific nutrients to maize. Mineral content of both substrate and plant leaves, growth, chlorophyll fluorescence and photosynthetic pigments were measured following six weeks of cultivation. As steel slag also contains trace amounts of heavy metals, certain oxidative parameters (antioxidative enzyme activities and lipid peroxidation) were evaluated as well. The steel slag improved soil mineral composition, increased above ground maize biomass by providing Fe, Mn, Mg, K and partly P and improved photosynthetic parameters. The potential phytotoxicity of EAF slag containing substrates was not determined as evaluated by MDA (malondialdehyde), GR (glutathione reductase) and APX (ascorbate peroxidase) levels. The obtained results show that EAF steel slag is comparable to NPK + F e in supplying nutrients for maize growth, indicating the potential of EAF steel slag as an inexpensive and non-phytotoxic nutrient supplier especially in poor soils.

  10. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming


    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities.

  11. Some Insights to the Reuse of Dredged Marine Soils by Admixing with Activated Steel Slag

    Chee-Ming Chan


    Full Text Available Regular dredging is necessary for the development of coastal regions and the maintenance of shipping channels. The dredging process dislodges sediments from the seabed, and the removed materials, termed dredged marine soils, are generally considered a geowaste for dumping. However, disposal of the dredged soils offshores can lead to severe and irreversible impact on the marine ecosystem, while disposal on land often incurs exorbitant costs with no guarantee of zero-contamination. It is therefore desirable to reuse the material, and one option is solidification with another industrial waste, that is, steel slag. This paper describes the exploratory work of admixing dredged marine soil with activated steel slag for improvement of the mechanical properties. An optimum activation concentration of NaOH was introduced to the soil-slag mixture for uniform blending. Specimens were prepared at different mix ratios then left to cure for up to 4 weeks. The unconfined compressive strength test was conducted to monitor the changes in strength at predetermined intervals. It was found that the strength does not necessarily increase with higher steel slag content, indicating an optimum slag content required for the maximum solidification effect to take place. Also, regardless of the slag content, longer curing time produces greater strength gain. In conclusion, steel slag addition to dredged sediments can effectively strengthen the originally weak soil structure by both the “cementation” and “filler” effects, though the combined effects were not distinguished in the present study.

  12. Thermodynamic and Experimental Investigations of High-Temperature Refractory Corrosion by Molten Slags

    Wagner, Christoph; Wenzl, Christine; Gregurek, Dean; Kreuzer, Daniel; Luidold, Stefan; Schnideritsch, Holger


    Corrosion mechanisms between MgO refractory substrates and FeNi slags were investigated. The FeNi slags taken into consideration represent a simple synthetically mixed slag with specific oxides and a real slag from a ferroalloy producer. The MgO refractory substrates with the specimens of FeNi slag were heated in a hot-stage microscope at 10 K/min from room temperature to three different temperatures 1573 K, 1723 K, and 1923 K (1300 °C, 1450 °C, and 1650 °C). The experiments were carried out under a controlled gas atmosphere that simulates the relevant process conditions. The corrosion mechanisms of each system were followed by scanning electron microscope analyses. The results obtained showed that slag corrosion dominates, with a pronounced partial dissolution of refractory fines forming Mg-silicates of type forsterite. It was also observed that iron oxide present in the slag diffused into the coarse refractory grains forming magnesiowustite. Finally, the results obtained were compared with those predicted by FACTSAGE software to understand the corrosion mechanisms and draw implications for improving the refractory performance and lifetime.

  13. Effect of blast furnace slag on self-healing of microcracks in cementitious materials

    Huang, Haoliang, E-mail: [Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology (Netherlands); Ye, Guang [Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology (Netherlands); Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University (Belgium); Damidot, Denis [Université Lille Nord de France (France); EM Douai, LGCgE-MPE-GCE, Douai (France)


    The physico-chemical process of self-healing in blast furnace slag cement paste was investigated in this paper. With a high slag content i.e., 66% in cement paste and saturated Ca(OH)₂ solution as activator, it was found that the reaction products formed in cracks are composed of C-S-H, ettringite, hydrogarnet and OH–hydrotalcite. The fraction of C-S-H in the reaction products is much larger than the other minerals. Large amount of ettringite formed in cracks indicates the leaching of SO₄⁻² ions from the bulk paste and consequently the recrystallization. Self-healing proceeds fast within 50 h and then slows down. According to thermodynamic modeling, when the newly formed reaction products are carbonated, the filling fraction of crack increases first and then decreases. Low soluble minerals such as silica gel, gibbsite and calcite are formed. Compared to Portland cement paste, the potential of self-healing in slag cement paste is higher when the percentage of slag is high. Highlights: • Self-healing reaction products in slag cement paste were characterized. • Self-healing reaction products formed in time were quantified with image analysis. • Self-healing in slag cement paste was simulated with a reactive transport model. • Effect of carbonation on self-healing was investigated by thermodynamic modeling. • Effect of slag on self-healing was discussed based on experiments and simulation.

  14. Thermodynamic and Experimental Investigations of High-Temperature Refractory Corrosion by Molten Slags

    Wagner, Christoph; Wenzl, Christine; Gregurek, Dean; Kreuzer, Daniel; Luidold, Stefan; Schnideritsch, Holger


    Corrosion mechanisms between MgO refractory substrates and FeNi slags were investigated. The FeNi slags taken into consideration represent a simple synthetically mixed slag with specific oxides and a real slag from a ferroalloy producer. The MgO refractory substrates with the specimens of FeNi slag were heated in a hot-stage microscope at 10 K/min from room temperature to three different temperatures 1573 K, 1723 K, and 1923 K (1300 °C, 1450 °C, and 1650 °C). The experiments were carried out under a controlled gas atmosphere that simulates the relevant process conditions. The corrosion mechanisms of each system were followed by scanning electron microscope analyses. The results obtained showed that slag corrosion dominates, with a pronounced partial dissolution of refractory fines forming Mg-silicates of type forsterite. It was also observed that iron oxide present in the slag diffused into the coarse refractory grains forming magnesiowustite. Finally, the results obtained were compared with those predicted by FACTSAGE software to understand the corrosion mechanisms and draw implications for improving the refractory performance and lifetime.

  15. Uranium recovery from slags of metallic uranium; Recuperacao de uranio em escorias de uranio metalico

    Fornarolo, F.; Frajndlich, E.U.C.; Durazzo, M. [Instituto de Pesquisas Energeticas e Nucleares (CNEN/IPEN-SP), Sao Paulo, SP (Brazil). Centro de Combustiveis Nucleares], e-mail:


    The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U{sub 3} Si{sub 2}) from Hexafluoride of Uranium (UF{sub 6}) with enrichment 20% in weight of {sup 235}U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U{sub 3}O{sub 8} is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U{sub 3}O{sub 8}. Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

  16. Slag Behavior in Gasifiers. Part I: Influence of Coal Properties and Gasification Conditions

    Ping Wang


    Full Text Available In the entrained-flow gasifiers used in integrated gasification combined cycle (IGCC plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter is entrained (as fly ash with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. To improve gasification availability through better design and operation of the gasification process, a better understanding of slag behavior and the characteristics of the slagging process is needed. Char/ash properties, gas compositions in the gasifier, the gasifier wall structure, fluid dynamics, and plant operating conditions (mainly temperature and oxygen/carbon ratio all affect slagging behavior. Because coal has varying ash content and composition, different operating conditions are required to maintain the slag flow and limit problems downstream. In Part I, we review the main types and the operating conditions of entrained-flow gasifiers and coal properties used in IGCC plants; we identify and discuss the key coal ash properties and the operating conditions impacting slag behavior; finally, we summarize the coal quality criteria and the operating conditions in entrained-flow gasifiers. In Part II, we discuss the constitutive modeling related to the rheological studies of slag flow.

  17. Investigation on the Copper Content of Matte Smelting Slag in Peirce-Smith Converter


    The copper contents and its existing forms in the slags duri ng the slag-making stage of Peirce-Smith converters in Guixi Smelter, Jiangxi Province, China have been investigated. The investigation was based on plant trials with the corresponding thermodynamic calculation s and kinetic considerations. From the plant data, the total copper co ntent in the slags was in the range of 2% to 8 % (mass fraction). The mechanical entrainment of matte drops has been found to be the main ca use of the copper loss. The suspension index, defined as the ratio of the mass fraction of copper in suspended matte drops in the slag to th at in bulk of the matte phase, has been adopted to quantify the matte entrainment. The values of this parameter estimated in this work have been found mainly within a range of 2.5%€?.0%. The Fe3O4 content in t he slag has been estimated to be the most important factor, among othe rs, influencing the separation of slag with matte and, consequently, t he copper loss from the slag.

  18. Ecotoxicity of Concretes with Granulated Slag from Gray Iron Pilot Production as Filler

    Helena Hybská


    Full Text Available This paper focuses on research concerning the ecotoxicological properties of granulated slag from the pilot production of gray iron with red mud addition and concrete composites with the application of this slag. Red mud is a hazardous waste generated in the production of aluminium oxide. Negative ecotoxicological tests are, therefore, one of the basic prerequisites for the ability to use granulated slag from gray iron pilot production. Granulated slag and concrete composite samples with various ratios of granulated slag have been subject to ecotoxicity tests: determining root growth inhibition in the highly-cultivated plant Sinapis alba, and determining acute toxicity in Daphnia magna. The results of ecotoxicological testing of granulated slag from gray iron standard production and gray iron pilot production with the additive were, according to the standard (STN 83 8303, negative. Additionally, the results of ecotoxicological tests of concrete composites were negative, with the exception of a 50% substitution of fine aggregate with slag from gray iron pilot production.

  19. Evolution of the global phosphorus cycle

    Reinhard, Christopher T.; Noah J. Planavsky; Gill, Benjamin C.; Ozaki, Kazumi; Robbins, Leslie J.; Lyons, Timothy W.; Fischer, Woodward W.; Wang, Chunjiang; Cole, Devon B.; Konhauser, Kurt O.


    The macronutrient phosphorus is thought to limit primary productivity in the oceans on geological timescales. Although there has been a sustained effort to reconstruct the dynamics of the phosphorus cycle over the past 3.5 billion years, it remains uncertain whether phosphorus limitation persisted throughout Earth’s history and therefore whether the phosphorus cycle has consistently modulated biospheric productivity and ocean–atmosphere oxygen levels over time. Here we present a compilation o...

  20. Thoracic surgical implications of the yellow nail syndrome.

    David, I; Crawford, F A; Hendrix, G H; Harley, R A; Tucker, T


    Idiopathic lymphedema associated with yellow discoloration of the nail beds constitutes the yellow nail syndrome. Pleural effusions and chronic sinusitis are also frequently present. This report describes a case of yellow nail syndrome in a 65-year-old woman.


    Bert Zauderer


    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. The reacted particles impact and melt in the liquid slag layer on the combustor wall by the centrifugal force of the swirling combustion gases. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Prior analyses and laboratory scale data indicated that for Coal Tech's 20 MMBtu/hour, air-cooled, slagging coal combustor slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to validate this sulfur-in-slag model in a group of combustor tests. A total of 36 days of testing on the combustor were completed during the period of performance of this project. This was more that double the 16 test days that were required in the original work statement. The extra tests were made possible by cost saving innovations that were made in the operation of the combustor test facility and in additional investment of Coal Tech resources in the test effort. The original project plan called for two groups of tests. The first group of tests involved the injection of calcium sulfate particles in the form of gypsum or plaster of Paris with the coal into the 20 MMBtu/hour-combustor. The second group of tests consisted of the entire two-step process, in which lime or limestone is co-injected with coal and reacts with the sulfur gas released during combustion to form calcium sulfate particles that impact and dissolve in the slag layer. Since this sulfur capture process has been validated in numerous prior tests in this combustor, the primary effort in the present project was on achieving the high slag flow rates needed to retain the sulfur in the slag.

  2. Guiding phosphorus stewardship for multiple ecosystem services

    Phosphorus is vital to agricultural production and water quality regulation. While the role of phosphorus in agriculture and water quality has been studied for decades, the benefits of sustainable phosphorus use and management for society due to its downstream impacts on multiple ecosystem services...

  3. Kinetics of the dissolution of zinc sulfide in an oxidizing slag

    Gupta, Suresh K.


    A new concept has been developed for the production of zinc from zinc and complex zinc concentrates. It is a two-stage process involving oxidation of zinc sulfide to oxide and dissolution into slag and the fuming of zinc from the slag by injecting carbonaceous materials into it to produce zinc vapors which can be subsequently condensed in a lead-splash condenser such as those used in the Imperial Smelting Process (ISP). In this paper, the effects of the quantity of air, temperature, and concentrate feed rate have been discussed on the production of zinc-rich slag, which is the first stage of the proposed process.

  4. [Study on quantificational analysis method for the non-crystalline content in blast furnace slag].

    Yan, Ding-Liu; Guo, Pei-Min; Qi, Yuan-Hong; Zhang, Chun-Xia; Wang, Hai-Feng; Dai, Xiao-Tian


    Quantificational analysis method for the non-crystalline and crystalline contents in blast furnace slag was studied by means of X-ray diffraction. The process of quantificational analysis method includes standard samples preparation, samples preparation, X-ray diffraction measurement and data treatment. The data treatment includes integration areas of non-crystalline curve and crystalline peaks in certain diffraction angle range, linear fitting and quantificational coefficient determination. The preparation methods of standard samples for X-ray diffraction of blast furnace slag were proposed, including 100% crystalline sample and 100% non-crystalline sample. The 100% crystalline sample can be obtained by heating blast furnace slag for 12 h at 1 000-1 200 degrees C, and the 100% non-crystalline sample can be obtained by quenching the molten slag with enough water. The X-ray diffraction method of quantificational analysis of non-crystalline content in blast furnace slag was proposed with the 100% non-crystalline and 100% crystalline standard samples, and the quantificational coefficient can be obtained by linear regression on the integration areas of non-crystalline curve and crystalline peaks of X-ray diffraction in the 2-theta range 20 degrees-40 degrees. This method is suitable for the blast furnace slag with the non-crystalline content over 80%. The non-crystalline and crystalline contents of original blast furnace slag are obtained by combining the X-ray diffraction results and mathematical treatment, and this method is suitable for the blast furnace slag with the non-crystalline content over 90%, whose process includes preparing the 100% crystalline standard sample by heating blast furnace slag for 12 h at 1000-1200 degrees C, samples preparation with the 0.02 interval in the 0-0.1 mass ratio range of 100% crystalline to original slag, X-ray diffraction measurement of the samples prepared and data treatment using iterative linear regression. The

  5. Statistical modeling of copper losses in the silicate slag of the sulfide concentrate smelting process


    This article presents the results of the statistical modeling of copper losses in the silicate slag of the sulfide concentrates smelting process. The aim of this study was to define the correlation dependence of the degree of copper losses in the silicate slag on the following parameters of technological processes: SiO2, FeO, Fe3O4, CaO and Al2O3 content in the slag and copper content in the matte. Multiple linear regression analysis (MLRA), artificial neural networks (ANNs) and adaptive netw...

  6. The influence of the silicate slag composition on copper losses during smelting of the sulfide concentrates


    This paper presents the results of multi-linear regression analysis (MLRA) of the slag composition (SiO2, FeO, Fe3O4, CaO, Al2O3) and the content of copper in the matte on resulting copper content in the slag during smelting of the sulfide concentrates in the reverberatory furnace. When comparing results obtained with MLRA model calculations with values measured at industrial level high degree of fitting is obtained (R2 = 0.974). This indicates that slag composition and content of copper in t...

  7. Influence of Environmental Factors on the Volume Change of Blended Cement Containing Steel Slag


    In the condition of 20 ℃, 5% sulfate liquor curing, standard tap water curing and 50% RH curing-three different curing environments, the volume change of steel slag blended cement influenced by environmental factors was studied. With steel slag addition 10%, 30%, 50%, from 90 days to 356 days, the relationship of shrinkage and three different curing environments is: dry curing environment>tap water curing environment>sulfate curing environment. But, the sample shrinkage in 28 days has much difference with the curing environment, which has no obvious orderliness. The different effects on blended cement containing steel slag in different environmental factors were analyzed using SEM.

  8. Utilization of steel melting electric arc furnace slag for development of vitreous ceramic tiles

    Ritwik Sarkar; Nar Singh; Swapan Kumar Das


    Steel melting through electric arc furnace route is gaining popularity due to its many advantages, but generates a new waste, electric arc furnace slag, which is getting accumulated and land/mine filling and road construction are the only utilization. This slag has been tried to be value added and utilized to develop vitreous ceramic tiles. Slag, to the extent of 30–40 wt% with other conventional raw materials, were used for the development in the temperature range 1100–1150°C. The fired products showed relatively higher density with shorter firing range and good strength properties. Microstructural and EDAX studies were also done to evaluate the developed products.

  9. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.


    ... phosphorus consuming subcategory. 422.20 Section 422.20 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Consuming Subcategory § 422.20 Applicability; description of the phosphorus consuming subcategory... manufacture of phosphoric acid, phosphorus pentoxide, phosphorus pentasulfide, phosphorus trichloride,...

  10. Greening the global phosphorus cycle

    Withers, Paul J.A.; Elser, James J.; Hilton, Julian; Ohtake, Hisao; Schipper, Willem J.; Dijk, Van Kimo C.


    The sustainability of global phosphorus (P) use is emerging as a major societal goal to secure future food, energy, and water security for a growing population. Phosphate rock (PR) is a critical raw material whose inefficiency of use is leading to widespread eutrophication and uncertainties about

  11. [Pleuritis in yellow nail syndrome].

    Kossakowski, C A; Schmiegelow, P; Müller, K-M


    A 76-year-old man presented clinically with coughing and shortness of breath and was diagnosed radiologically to have massive pleural effusion as a combined feature of yellow nail syndrome. A lung biopsy was taken and revealed histologically: chronic non-specific inflammation in the pleuropulmonary border, intrapleural edema with eightfold pleural thickening in comparison to normal, angiogenesis in both the nutritive and functional intrapleural blood vessels, no abnormalities of lymphatic vessels with normal topographical distribution as detected by immunohistochemistry for antibody D2-40, granulomatous chronic foreign body reaction as a consequence of pleural effusion therapy by talcum pleurodesis.The histopathological findings of chronic non-specific pleuritis with angiogenesis and increased permeability of blood vessels led to massive intrapleural edema with pleural effusion. Abnormalities of lymphatic vessels could not be confirmed. Considering the features of this disease, they are probably secondary to chronic r infectious or immunological inflammation or paraneoplastic complications with angiogenesis (in about 19%).

  12. Natural phosphorus sources for the Pacific Northwest

    Johnson, Hank


    Phosphorus is a naturally occurring element found in all rocks; the amount varies by the type of rock. The amount of phosphorus in sediments is expected to be correlated with the amount of phosphorus in the parent rocks. Streambed sediment collected by the National Uranium Resource Evaluation (NURE) Program were used to estimate the variation of phosphorus across the Pacific Northwest. This file provides an estimate of the mean concentration of phosphorus in soils for each incremental catchment of the USGS Pacific Northwest SPARROW model.

  13. Environmental Phosphorus Recovery Based on Molecular Bioscavengers

    Gruber, Mathias Felix

    Phosphorus is a ubiquitous element of all known life and as such it is found throughout numerous key molecules related to various cellular functions. The supply of phosphorus is tightly linked to global food security, since phosphorus is used to produce agricultural fertilizers, without which...... it would not be possible to feed the world population. Sadly, the current supply of phosphorus is based on the gradual depletion of limited fossil reserves, and some estimates predict that within 15-25 years we will consume more phosphorus than we can produce. There is therefore a strong international...

  14. Composite cements containing natural pozzolan and granulated blast furnace slag

    Irassar, E. F.


    Full Text Available For reasons of market demand and Portland cement production,the manufacture of cements with two or more separately ground additions to produce customized cements is becoming common practice.When pozzolan or slag content in this type of cements is high, however, the initial strength of the resulting product may be adversely impacted. This problem can be minimized by activating one or both of the replacement materials. The present study analyzes the effect of Portland cement additions such as physically activated natural pozzolan(up to 20% and/or granulated blast furnace slag (up to 35% on mortar flexural and compressive strength. The results show that higher strength is attained in ternary than binary cements. Initially (2 and 7 days, the highest compressive strengths are reached by mortars with up to 13% natural pozzolan and 5% slag, whereas at later ages mortars with larger proportions of additions are found to perform best.Debido a las exigencias del mercado y de la producción de cemento Portland, es cada vez más frecuente la elaboración de cementos con dos o más adiciones a partir de la molienda separada de sus constituyentes, dando origen a la formulación de los cementos a medida.Cuando el contenido de adiciones es alto, la utilización de puzolana y escoria en este tipo de cementos presenta la peculiaridad de disminuir la resistencia inicial del cemento resultante. Sin embargo, si algunas o ambas adiciones se activan, este problema puede minimizarse. En este trabajo se analiza la influencia de la incorporación al cemento Portland de puzolana natural (hasta 20% activada físicamente y/o escoria granulada de alto horno (hasta 35% sobre la resistencia a flexión y a compresión de morteros. Los resultados indican que los cementos ternarios presentan un mejor comportamiento resistente que los cementos binarios. Las máximas resistencias a compresión en las primeras edades (2 y 7 díasse alcanzan con hasta 13% de puzolana natural y 5% de

  15. 高炉渣改性作为矿渣棉原料的试验%Experimental Research of Slag Wool Producing With Blast Furnace Slag

    郭强; 袁守谦; 刘军; 李海潮


    研究了不同酸度条件下,随着高炉熔渣中主要成分的变化,其黏度和表面张力对高炉渣作为矿渣棉原料的影响,并对其影响机制进行了探讨。结果表明,Al2O3和SiO2增加时,黏度增加,表面张力也随之加大,利于制取较长的矿渣棉纤维。%In this paper,the effect of viscosity and surface tension of furnace slag as slag wool material is studied in different acidity coefficient,with changing of the blast furnace slag in the main component.The influence mechanism had also been discussed.The results show that the slag viscosity decreases with the increase of Al2O3 content,at the same time,surface tension decreases too which benefits to make longer slag wool fibers.

  16. Evaluation of steel slag coarse aggregate in hot mix asphalt concrete.

    Ahmedzade, Perviz; Sengoz, Burak


    This paper presents the influences of the utilization of steel slag as a coarse aggregate on the properties of hot mix asphalt. Four different asphalt mixtures containing two types of asphalt cement (AC-5; AC-10) and coarse aggregate (limestone; steel slag) were used to prepare Marshall specimens and to determine optimum bitumen content. Mechanical characteristics of all mixtures were evaluated by Marshall stability, indirect tensile stiffness modulus, creep stiffness, and indirect tensile strength tests. The electrical sensitivity of the specimens were also investigated in accordance with ASTM D257-91. It was observed that steel slag used as a coarse aggregate improved the mechanical properties of asphalt mixtures. Moreover, volume resistivity values demonstrated that the electrical conductivity of steel slag mixtures were better than that of limestone mixtures.

  17. Effect of the cooling rate on the phase composition and structure of copper matte converting slags

    Selivanov, E. N.; Gulyaeva, R. I.; Udoeva, L. Yu.; Belyaev, V. V.; Pankratov, A. A.


    The effect of the cooling rate on the phase composition and microstructure of copper matte converting slags is studied by X-ray diffraction, combined thermogravimetry and calorimetry, mineragraphy, and electron-probe microanalysis. The compositions of oxide and sulfide phases are determined, and the forms of nonferrous metals in slags cooled at a rate of 0.3 and 900°C/s are revealed. At high cooling rates of the slags, iron silicate glass is shown to form apart from sulfide phases. Repeated heating of the slags leads to the development of devitrification, “cold” crystallization, and melting. A decrease in the cooling rate favors an increase in the grain sizes in oxides (magnetite, iron silicates) and sulfides (bornite-, sphalerite, and galena-based solid solutions).

  18. Increasing the efficiency of ladle desulfurization of steel by using regenerated slags

    Bigeev, V.A.; Petrov, L.V.; Vdovin, K.N.; Kotii, V.N.; Deryabin, A.V.


    The volume of steel subjected to ladle desulfurization can be increased by regenerating spent synthetic slags and returning them to the production cycle. Two problems encountered in the restoration of the desulfurizing properties of the slags are the need to reduce the content of the oxides of silicon and iron and remove sulfur to the 0.03-0.06 level. Difficulties and solutions of both problems are discussed and a scheme for regeneration is proposed which uses oxidation and reduction processes and considers such parameters as ladle and furnace lining protection and metal and slag separation measures. The scheme makes the expanded efficiency of ladle desulfurization of steel with regenerated slag a realistic option and will be recommended for introduction after the individual process and design parameters have been refined.

  19. Fluid Flow and Interfacial Phenomenon of Slag and Metal in Continuous Casting Tundish With Argon Blowing

    WANG Jun; ZHU Miao-yong; ZHOU Hai-bing; WANG Ying


    The fluid flow and the interracial phenomenon of slag and metal in tundish with gas blowing were studied with mathematical and physical modeling,and the effects of gas flowrate,the placement of porous beam for the generation of bubbles,and the combination of flow control devices on the flow and slag-metal interface were investigated.The results show that the position of gas bubbling has a significant effect on the flow in tundish,and the placement of porous beam and gas flowrate are the two main factors affecting the entrapment of slag in tundish.The closer the porous beam to the weir,the more reasonable is the flow,which is in favor of the control of slag entrapment in tundish.

  20. Utilizing of the metallurgical slag for production of cementless concrete mixtures

    D. Baricová


    Full Text Available In process of pig iron, steel and cast iron production besides main product, also secondary products are formed, that have character of secondary raw materials and industrial wastes. The most abundant secondary product originating in the metallurgical process is furnace slag. Total amount of accured slag, also its chemical, mineralogical, physical – chemical properties and similarity with natural stones predestinate its utilisation in different fields of industry. The contribution deals with production of cementless concrete mixtures, where the main parts were formed by blast furnace granulated slag grinded and different gravel slag from blast furnace, oxygen converter and electric arc furnace. As activators of solidification different kinds of water glass were tested.

  1. Characteristics of blast furnace slag leachate produced under reduced and oxidized conditions.

    Schwab, A P; Hickey, J; Hunter, J; Banks, M K


    A laboratory study was conducted to determine the environmental conditions necessary to reproduce leachates observed emerging from blast furnace slag acting as the foundation of highways in northwest Indiana. The leachates in the field are often highly alkaline with a pungent sulfur odor, a distinct green or milky-white in color, and sulfate concentrations exceeding 2,000 mg/L. Slag was equilibrated in the laboratory under both oxidized and anoxic environments and at various slag:water ratios. Constant anoxic conditions were required to produce to green colors in the slag, but high sulfate concentrations were observed only when the suspensions were fully oxidized. Leachate from the study site appears to form as a result of a series of complex chemical reactions including fluctuating oxidized and reduced conditions.

  2. Cleaning of waste smelter slags and recovery of valuable metals by pressure oxidative leaching.

    Li, Yunjiao; Perederiy, Ilya; Papangelakis, Vladimiros G


    Huge quantities of slag, a waste solid product of pyrometallurgical operations by the metals industry are dumped continuously around the world, posing a potential environmental threat due to entrained values of base metals and sulfur. High temperature pressure oxidative acid leaching of nickel smelter slags was investigated as a process to facilitate slag cleaning and selective dissolution of base metals for economic recovery. Five key parameters, namely temperature, acid addition, oxygen overpressure, solids loading and particle size, were examined on the process performance. Base metal recoveries, acid and oxygen consumptions were accurately measured, and ferrous/ferric iron concentrations were also determined. A highly selective leaching of valuable metals with extractions of >99% for nickel and cobalt, >97% for copper, >91% for zinc and metals, hematite and virtually zero sulfidic sulfur seems to be suitable for safe disposal. The process seems to be able to claim economic recovery of base metals from slags and is reliable and feasible.

  3. Study on the Kinetics of Aluminum Removal from Liquid Silicon to Slag with Mechanical Stirring

    Lee, Jaewoo; White, Jesse F.; Hildal, Kjetil; Sichen, Du


    The kinetics of aluminum removal from silicon melt to CaO-SiO2-Al2O3 slag was studied. A recently designed experimental setup using mechanical stirring was employed to focus the study on the chemical reaction. The slag and metal were found to reach chemical equilibrium in 300 seconds. A simple model could reproduce the experimental data satisfactorily. Both the experimental results and the model prediction further confirmed that the process was controlled by the chemical reaction, since the reaction rate constant was found to be independent of the amount of slag and the initial slag composition. The experimental data at equilibrium were compared with the model calculations. The discrepancy between the model calculations and the experimental data strongly suggests the need for careful thermodynamic measurements.

  4. Study on Microstructure and Slag Corrosion Mechanism of High Chrome Bricks for Gasifier


    Research was focused on slag corrosion mechanism of high chrome bricks used for different types of gasifier by comparing the structure of high chrome bricks for petroleum coke gasifier and water-coal slurry gasifier with slag corroded testing brick and water coal slurry gasifier through Scanning Electron Microscope (SEM) examination and X-ray diffraction. Results show that for high chrome brick used for petroleum coke gasifier, corrosion is mainly caused by Cr2O3 in the brick and V2O5 in molten slag and liquid phase generation at low temperature; for high chrome brick used for water-coal slurry gasifier, corrosion is caused by dissolution of Cr2O3 in molten slag and corrosion of ZrO2. For LIRR-HK95 brick, it performs better petroleum coke corrosion resistance than the others due to the optimal composition and structure.

  5. Short review on the origin and countermeasure of biomass slagging in grate furnace

    Yiming eZhu


    Full Text Available Given the increasing demand for energy consumption, biomass has been more and more important as a new type of clean renewable energy source. Biomass direct firing is the most mature and promising utilization method to date, while it allows a timely solution to slagging problems. Alkali metal elements in the biomass fuel and the ash fusion behavior, as the two major origins contributing to slagging during biomass combustion, are analyzed in this paper. The slag presents various layered structures affected by the different compositions of ash particles. Besides, the high-temperature molten material which provides a supporting effect on the skeletal structure in biomass ash was proposed to evaluate the ash fusion characteristics. In addition, numerous solutions to biomass slagging, such as additives, fuel pretreatment and biomass co-firing, were also discussed.

  6. Improving the behavior of body roads by the use of gravel-slag mixture

    Hadinane, Hocine; Oucief, Hocine; Merzoud, Mouloud


    The accumulation of wastes industrial stemming of the iron and steel industry has influenced negatively the environment. The adopted policy had for mission to eliminate these undesirable wastes by recycling them by their utilization in adequate areas. The objective of this work is to study the mechanical behavior of a gravel-slag based on crystallized and granulated slag, activated by lime. One will be interested in the study of resistance to punching and the bearing ratio of this slag through Proctor tests, CBR and by compression, tensile tests, for use in the layers of pavement (Foundation and base layers). The obtained result on gravel-slag show considerable performances, compared with natural aggregates point of resistance and thickness of the layers. Its utilization in the road area has allowed therefore the recycling these industrial wastes, to decrease the pollution, to use a minimum noble product requiring important exploitation energy and an economy on layers of surface realized with costly materials (bituminous concrete).

  7. Decomposition of acid dissolved titanium slag from Australia by sodium hydroxide

    FENG Yang; WANG Jinggang; WANG Lina; QI Tao; XUE Tianyan; CHU Jinglong


    The kinetics of the decomposition of acid dissolved titanium slag with a sodium hydroxide system under atmospheric pressure was studied. The effect of reaction temperature, particle size and NaOH-to-slag mass ratio on titanium extraction was investigated. The results show that temperature and particle size have significant influence on titanium extraction. The experimental data of titanium extraction show that the shrinking core model with chemical reaction controlled process is most applicable for the decomposition of slag, with an apparent activation energy of 62.4 kJ·mol~(-1). Approximately 85 wt.%-90 wt.% of the titanium can be extracted from the slag under the optimal conditions. In addition, the purity of titanium dioxide obtained in the product is up to 98.5 wt.%.

  8. Smelting chlorination method applied to removal of copper from copper slags

    李磊; 王华; 胡建杭


    In order to reasonably utilize the iron resources of copper slags, the smelting chlorination process was used to remove copper from copper slags. Higher holding temperature and O2 flow rate are beneficial to increasing copper removal rate. However, the Cu2O mode is formed by the reaction of surplus O2 and CuCl with O2 flow rate increasing over 0.4 L/min, causing CuCl volatilization rate and copper removal rate to decrease. The resulting copper removal rate of 84.34%is obtained under the optimum conditions of holding temperature of 1573 K, residence time of 10 min, CaCl2 addition amount of 0.1 (mass ratio of CaCl2 and the copper slag) and oxygen flow rate of 0.4 L/min. The efficient removal of copper from copper slags through chlorination is feasible.

  9. Anisotropy of Expansion Coefficient and Slag Resistance of Spinel Carbon Bricks

    YANG Ding'ao; YUAN Shouqian; JIANG Mingxue; DONG Sunzhen; ZHAO Zijian


    Effects of the pressure direction on the thermal expansion and slag corrosion resistance were investigated and anisotropic microstructures of flaky graphite in spinel carbon bricks were examined. The experimental results show that slag corrosion velocities in the direction parallel to the pressure direction display a decrease of 34% compared to those in the vertical direction. Meantime, the linear expansion coefficient in the direction parallel to the pressure direction is 2.45 times as large as that in the vertical pressure direction. Slag corrosion velocities of spinel carbon bricks soaked in the AOD melting slag display a 46%-47% decrease compared to those of magnesia carbon bricks. The microstructure observation shows that spinel carbon bricks have a high degree of preferred orientation.

  10. Corrosion Resistance of MgO-C Based Refractory to Slag Containing Titania

    LIU Qing-cai; SUN Ya-li; DU Yun-gui; CHEN Deng-fu


    The interaction between the slag containing titanium oxides (TiO2 of 2.0 %-20.0 %) and a MgO-C based refractory was investigated by immersion test. The relationship between TiO2 content in slag and corrosion rate of the refractory was studied. The microstructure and compositions of the corroded refractory were analyzed by SEM and X-ray diffraction. The corrosion mechanism of MgO-C based refractory in the slag containing titanium was proposed, and the effects of TiO2 content, slag basicity (ωCaO/ωSiO2) and temperature in molten bath on the corrosion rate of the refractory were obtained.

  11. Dissolution Kinetics of Magnesitic-Dolomite and Magnesite-Chrome Refractories in Secondary Steelmaking Slags

    CHEN Zhaoyou; WU Xuezhen; YE Fangbao


    Dissolution kinetics of magnesitic-dolomite and magnesite-chrome refractories in secondary steelmaking slags was studied by means of the rotating cylinder method under forced convection. Materials investigated include four magnesitic-dolomite samples (MgO content 40% to 93% ) and two magnesite-chrome samples ( co-clinkered and semi-rebonded ). Synthetic slags simulative of VOD and AOD slags with varying basicity (0. 6-2. 68) are used. The experiments are carried out in Ar atmosphere at different temperatures (1 600 ℃-1 750 ℃ ) and revolumicrostructure of specimens (before and after slag tests)are studied by optical microscopy, SEM and EPMA.Based on our experimental results the mechanism and kinetics of the dissolution process are discussed.

  12. Applicability of mass action law to sulphur distribution between slag melts and liquid iron


    According to the mass action law and the coexistence theory of slag structure, the calculating models of mass action concentration for CaO-MgO-FeO-Fe2O3-SiO2, CaO-MgO-MnO-FeO-Fe2O3-P2O5-SiO2 and CaO-MgO-MnO-FeO-Fe2O3-Al2O3-P2O5-SiO2 slag melts are formulated and sulphur distribution between the slag melts and liquid iron is treated. It is found that CaO, MnO and FeO promote desulphurization, while MgO is detrimental to desulphurization. In addition, the sulphur distribution coefficients between the slag melts and liquid iron are presented.

  13. Characterization Report on Sand, Slag, and Crucible Residues and on Fluoride Residues

    Murray, A.M.


    This paper reports on the chemical characterization of the sand, slag, and crucible (SS and C) residues and the fluoride residues that may be shipped from the Rocky Flats Environmental Technology Site (RFETS) to Savannah River Site (SRS).

  14. Synthesis of Calcium Silicate Hydrate based on Steel Slag with Various Alkalinities

    WANG Shuping; PENG Xiaoqin; GENG Jianqiang; LI Bin; WANG Kaiyu


    This study aimed to improve the hydraulic potential properties of the slag. Therefore, a method of dynamic hydrothermal synthesis was applied to synthesize calcium silicate hydrate. The phases and nanostructures were characterized by XRD, FTIR, TEM, and BET nitrogen adsorption. The influence of alkalinity of steel slag on its structures and properties was discussed. The experimental results show that, the main product is amorphous calcium silicate hydrate gel with flocculent or fibrous pattern with a BET specific surface area up to 77 m2/g and pore volume of 0.34 mL/g. Compared with low alkalinity steel slag, calcium silicate hydrate synthesized from higher alkalinity steel slag is prone to transform to tobermorite structure.

  15. Computational Modeling of Arc-Slag Interaction in DC Furnaces

    Reynolds, Quinn G.


    The plasma arc is central to the operation of the direct-current arc furnace, a unit operation commonly used in high-temperature processing of both primary ores and recycled metals. The arc is a high-velocity, high-temperature jet of ionized gas created and sustained by interactions among the thermal, momentum, and electromagnetic fields resulting from the passage of electric current. In addition to being the primary source of thermal energy, the arc jet also couples mechanically with the bath of molten process material within the furnace, causing substantial splashing and stirring in the region in which it impinges. The arc's interaction with the molten bath inside the furnace is studied through use of a multiphase, multiphysics computational magnetohydrodynamic model developed in the OpenFOAM® framework. Results from the computational solver are compared with empirical correlations that account for arc-slag interaction effects.


    İsa YÜKSEL


    Full Text Available This paper presents results of an experimental study about partial substitution of granulated blast-furnace slag (GBFS as fine aggregate in production of concrete paving blocks and kerbs. GBFS is replaced sand for different GBFS/sand ratios in concrete during production of kerb and paving block specimens. Some tests orienting towards strength and durability were applied on these specimens including control specimens that are produced with normal concrete. Then, the results of tested properties of GBFS-replaced specimens and control specimens were compared. GBFS decreases the compressive strength of paving blocks and kerbs according to the results. However, some durability properties which are more important than strength for these elements are improved with GBFS replacement. The most improved property was abrasion resistance. It is concluded that it is feasible to use GBFS in paving block and kerb production with an optimum replacement ratio for these specimens.

  17. Computational Modeling of Arc-Slag Interaction in DC Furnaces

    Reynolds, Quinn G.


    The plasma arc is central to the operation of the direct-current arc furnace, a unit operation commonly used in high-temperature processing of both primary ores and recycled metals. The arc is a high-velocity, high-temperature jet of ionized gas created and sustained by interactions among the thermal, momentum, and electromagnetic fields resulting from the passage of electric current. In addition to being the primary source of thermal energy, the arc jet also couples mechanically with the bath of molten process material within the furnace, causing substantial splashing and stirring in the region in which it impinges. The arc's interaction with the molten bath inside the furnace is studied through use of a multiphase, multiphysics computational magnetohydrodynamic model developed in the OpenFOAM® framework. Results from the computational solver are compared with empirical correlations that account for arc-slag interaction effects.

  18. Orgin of Slag from Early Medieval Age Furnaces in Nitra

    Julius Dekan


    Full Text Available Two types of archaeological artefacts from remains of Early Medieval Age furnaces excavated in Nitra are analysed. They are supposed to originate from slag of glass and iron production. Employing Mossbauer spectrometry, iron crystallographic sites are identified and compared. In all samples, Fe2+ and Fe3+ structural positions were revealed. Some of the archeological artefacts including those that were supposed to originate from glass production show a presence of metallic iron and/or magnetic oxides. Based on the results of Mossbauer effect measurements performed at room temperature as well as 77 K (liquid nitrogen temperature analytical evidence is provided that the iron sites identified are not as those usually encountered in glasses. Consequently, a conclusion is proposed that neither of the investigated furnaces was used for glass production.

  19. Alkaline activated slag cements. Determination of reaction degree

    Fernández-Jiménez, A.


    Full Text Available The aim of the present work was to evaluate the validity of non-calorimetric different methods, used in the determination of reaction degree of alkaline activated slag pastes. The methods used were: (a chemical separation by methanol-salicylic acid; (b determination of the weight loss mass between 100-600°C in TG curves, associated to chemically combined water; (c quantification of the -74 ppm signal in 29Si MAS-NMR spectra. The parameters considered in the process were: nature of the alkaline activator (Waterglass, Na2CO3 and NaOH, activator concentration (4% and 3% Na2O in mass with respect to the slag, curing temperature (25 and 45°C, slag specific surface (460 and 900 m2/kg and time of reaction (from 7 days to 18 months. The results obtained indicate that none of the three methods is definitive but complementary and they provide to follow the reactive evolution of the alkaline activated slag cements. The method based on the quantification of the -74 ppm signal in the 29Si MAS NMR is the most suitable method.

    El objetivo del presente trabajo fue evaluar la validez de diferentes métodos, no calorimétricos, utilizados en la determinación del grado de reacción de pastas de escoria activada alcalinamente. Los métodos utilizados fueron: (a método de separación química por disolución en metanol ácido-salicílico; (b determinación de las pérdidas de masa entre 100-600°C en las curvas de TG, pérdidas asociadas a la cantidad de agua químicamente combinada: (c cuantificación de la señal de -74 ppm de los espectros de 29Si RMN MAS. Las variables consideradas en el proceso fueron: naturaleza del activador alcalino (Waterglass, Na2CO3 y NaOH, concentración del activador (4% y 3% de Na2O en masa respecto a la escoria, temperatura de curado (25 y 45°C, superficie específica de la escoria (460 y 900 m2/kg y

  20. Measurement of Moisture Content in Sand, Slag, and Crucible Materials

    Gray, J.H.


    The deinventory process at Rocky Flats (RFETS) has included moisture content measurements of sand, slag, and crucible (SSC) materials by performing weight loss measurements at 210 degrees - 220 degrees Celsius on representative samples prior to packaging for shipment. Shipping requirements include knowledge of the moisture content. Work at the Savannah River Technology Center (SRTC) showed that the measurement at 210 degrees - 220 degrees Celsius did not account for all of the moisture. The objective of the work in this report was to determine if the measurement at 210 degrees - 220 degrees Celsius at RFETS could be used to set upper bounds on moisture content and therefore, eliminate the need for RFETS to unpack, reanalyze and repack the material.

  1. A Brief Review of Viscosity Models for Slag in Coal Gasification

    Massoudi, Mehrdad; Wang, Ping


    Many researchers have defined the phenomenon of 'slagging' as the deposition of ash in the radiative section of a boiler, while 'fouling' refers to the deposition of ash in the convective-pass region. Among the important parameters affecting ash deposition that need to be studied are ash chemistry, its transport, deposit growth, and strength development; removability of the ash deposit; heat transfer mechanisms; and the mode of operation for boilers. The heat transfer at the walls of a combustor depends on many parameters including ash deposition. This depends on the processes or parameters controlling the impact efficiency and the sticking efficiency. For a slagging combustor or furnace, however, the temperatures are so high that much of the coal particles are melted and the molten layer, in turn, captures more particles as it flows. The main problems with ash deposition are reduced heat transfer in the boiler and corrosion of the tubes. Common ways of dealing with these issues are soot blowing and wall blowing on a routine basis; however, unexpected or uncontrolled depositions can also complicate the situation, and there are always locations inaccessible to the use of such techniques. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1300 C and 1500 C, the viscosity is approximately 25 Pa {center_dot} s. As the operating temperature decreases, the slag cools and solid crystals begin to form. In such cases the slag should be regarded as a non-Newtonian suspension, consisting of liquid silicate and crystals. A better understanding of the rheological properties of the slag, such as yield stress and shear-thinning, are critical in determining the optimum operating conditions. To develop an accurate heat transfer model in any type of coal combustion or gasification process, the heat transfer and to some extent the rheological properties

  2. Deoxidation Limits of Titanium Alloys during Pressure Electro Slag Remelting

    Bartosinski, M.; Hassan-Pour, S.; Friedrich, B.; Ratiev, S.; Ryabtsev, A.


    This paper focuses on deoxidation of titanium alloys produced by aluminothermic reduction (ATR) and subsequent homogenizing and alloying by vacuum induction melting (VIM). The main goal of the performed research work is to outline the deoxidation limit during pressure electro slag remelting (PESR) of the described material. To obtain electrodes for deoxidation, a Ti-24Al-16V masteralloy was produced by ATR and afterwards melted in a 0.5 litre calcium- zirconate (lab scale) or 14 litres high purity calcia (pilot scale) crucibles with continuous addition of Ti-sponge after reaching liquid state in order to obtain a final Ti-6Al-4V alloy. During melting, in both cases evaporation of calcium was noticed. The cast ingots were analysed for oxygen using inert gas fusion method, matrix and alloying elements were analysed by XRF. Results show oxygen levels between 0.5 and 0.95 wt.-% for the ingots which were melted in calcium-zirconate crucibles and approx. 1 - 1.2 wt.-% for the material produced by utilization of calcia crucibles. The subsequent deoxidation was carried out in lab and pilot scale electroslag remelting furnaces using a commercially pure calcium fluoride slag and metallic calcium as deoxidation agent. It could be shown, that deoxidation of the highly contaminated material is possible applying this method to a certain limit. Pilot scale trials showed a reduction of oxygen contents by 1500 - 3500 ppm. Oxygen levels in lab scale trials showed weaker deoxidation effects. In order to describe the achieved deoxidation effects in a quantitative way, the analyzed oxygen contents of the obtained ingots are compared with calculated data resulting from a mathematical kinetic model. The modelled datasets are in good agreement with experimental oxygen values.

  3. Wettability of Silicon Carbide by CaO-SiO2 Slags

    Safarian, Jafar; Tangstad, Merete


    The wettability of silicon carbide by liquid CaO-SiO2 slags that contain 47 to 60 wt pct SiO2 was studied using the sessile drop wettability technique. The experiments were carried out in Ar and CO atmospheres. A small piece of slag was melted on SiC substrates under different heating regimes up to 1600 °C. It was found that the wetting is not significantly dependent on the temperature and the heating rate. However, the wettability is relatively high, and the wetting is higher for slags that contain lower SiO2 concentrations. Moreover, the wettability between the slags and SiC is dependent on the gas phase composition, and it is higher in Ar than that in CO. When the SiO2 concentration changes from 47 pct wt to 60 pct wt, the wetting angle changes from 20 deg to 73 deg in Ar and from 58 deg to 87 deg in a CO atmosphere. The formation and bursting of gas bubbles also was observed after some contact time, which indicates that the wetting system is a reactive type. However, microscopic studies indicated that no metal phase exists at the slag/silicon-carbide interface. Therefore, it was concluded that chemical reactions between the slag and SiC take place and that SiO2 is slowly reduced to form CO and SiO gases. Based on the experimental data, the dependence of the Girifalco-Good coefficient on the slag composition and the relationship between the interfacial tension of CaO-SiO2 slags and SiC also were estimated.

  4. Late Bronze age metallurgy in the Italian Eastern Alps: copper smelting slags and mine exploitation


    At the end of the second millennium B.C., the extractive metallurgy of copper in Trentino (Italy) achieved a peak of technological efficiency and mass production, as evidenced by the large number of metallurgical sites and the huge amount of slags resulting from the smelting activities. Though different scholars proposed several smelting process models, so far an agreed interpretation of the whole process is lacking. Over 70 slags from the Luserna, Transacqua and Segonzano sites (all l...

  5. Prediction of coal slag foaming under gasification conditions by thermodynamic equilibrium calculations

    Lim, S.; Oh, M. [Hongik University, Seoul (Republic of Korea). School of Chemical Engineering


    In slagging gasifiers, slag foaming can cause serious operational problems, so there is a need for investigation into the conditions causing slag foaming. Viscosity experiments were carried out examining viscosity, extent of swelling and Fe formation. Although extensive swelling was not observed, FeO reduction was observed under an N{sub 2}/CO gas atmosphere, but not under CO{sub 2}/CO. In order to predict FeO reduction conditions in the gasifier, a model for an adiabatic equilibrium gasifier was developed. The gas composition, the amount of gas to slag, and PO{sub 2} were calculated for a slurry-feed gasifier, and the results of the calculation were used to predict the reduction of FeO in slag by using FactSage. Under typical gasification conditions for Denisovsky coal, the predicted -O{sub 2} in the gasifier was not low enough to cause FeO reduction. The FactSage simulation for the viscometer conditions predicted no FeO reduction under a CO/CO{sub 2} atmosphere, but did predict Fe formation under CO/N{sub 2} conditions. At a 20% CO concentration, FeO reduction starts at temperatures above 1,600{sup o}C. Since the slag has a low viscosity at 1,600{sup o}C, the oxygen bubble may have escaped as it formed. Therefore, slag foaming, caused by FeO reduction in the slag, can only occur when the right conditions of viscosity and oxygen partial pressure are met.

  6. The Revovery of Copper and Cobalt from Oxidized Copper Ore and Converter Slag



    The aim of this study was to develop a method for obtaining copper and cobalt from oxidized copper ore and converter slag. In order to convert the copper and cobalt into sulfate compounds the main step was to roast the samples obtained by sulfurization and transfer the samples into solution. First the oxidized copper ore was roasted, followed by the mixture of converter slag and oxidized copper ore. Since the levels of copper and cobalt were low, the sulfurization process was carri...

  7. Utilization of lightweight materials made from coal gasification slags. Quarterly report, September 1--November 30, 1997



    In previous projects, Praxis investigated the utilization of as-generated slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, the authors found that it would be extremely difficult for as-generated slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1,400 and 1,700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase 1, comprising the production of LWA and ULWA from slag at the large pilot scale, and Phase 2, which involves commercial evaluation of these aggregates in a number of applications. This document summarizes the Phase 2 accomplishments to date along with the major accomplishments from Phase 1.

  8. Evaluation on chemical stability of lead blast furnace (LBF) and imperial smelting furnace (ISF) slags.

    Yin, Nang-Htay; Sivry, Yann; Guyot, François; Lens, Piet N L; van Hullebusch, Eric D


    The leaching behavior of Pb and Zn from lead blast furnace (LBF) and imperial smelting furnace (ISF) slags sampled in the North of France was studied as a function of pHs and under two atmospheres (open air and nitrogen). The leaching of major elements from the slags was monitored as a function of pH (4, 5.5, 7, 8.5 and 10) under both atmospheres for different slag-water interaction times (1 day and 9 days). The leaching results were coupled with a geochemical model; Visual MINTEQ version 3.0, and a detailed morphological and mineralogical analysis was performed on the leached slags by scanning and transmission electron microscopy (SEM and TEM). Significant amounts of Ca, Fe and Zn were released under acidic conditions (pH 4) with a decrease towards the neutral to alkaline conditions (pH 7 and 10) for both LBF and ISF slags. On the other hand, Fe leachability was limited at neutral to alkaline pH for both slags. The concentrations of all elements increased gradually after 216 h compared to initial 24 h of leaching period. The presence of oxygen under open-air atmosphere not only enhanced oxidative weathering but also encouraged formation of secondary oxide and carbonate phases. Formation of carbonates and clay minerals was suggested by Visual MINTEQ which was further confirmed by SEM & TEM. The hydration and partial dissolution of hardystonite, as well as the destabilization of amorphous glassy matrix mainly contributed to the release of major elements, whereas the spinel related oxides were resistant against pH changes and atmospheres within the time frame concerned for both LBF and ISF slags. The total amount of Pb leached out at pH 7 under both atmospheres suggested that both LBF and ISF slags are prone to weathering even at neutral environmental conditions.

  9. Spatial distribution of chromium in soils contaminated by chromium-containing slag

    HUANG Shun-hong; PENG Bing; YANG Zhi-hui; CHAI Li-yuan; XU You-ze; SU Chang-qing


    To evaluate the metal chromium (Cr) contamination of soil at a chromium-containing slag site by ferrochromium production, the contaminated sites, under slag heap, in the vicinity of slag heap and arable soils near the outlet of sewer channel, and unpolluted site 5 km away from one ferroalloy plant in Hunan Province, China, were selected. The concentrations of total Cr and water soluble Cr in bulk soil samples and profile depth samples were determined. The results show that the soils in the vicinity of slag heap have the highest total Cr content followed by the soils under the slag heap and near the outlet of sewer channel of the factory. The mean concentrations of total Cr in the top soils at above three contaminated locations exceed the critical level of Secondary Environmental Quality Standard for Soil in China by 3.5, 5.4 and 1.8 times. In most Cr polluted soils, total Cr has a relative accumulation in soil depth of 40-60 cm, but this trend is not found in unpolluted soils. The average concentrations of water soluble Cr (Ⅵ) in top soils under slag heap and in the vicinity of slag heap are 176.9 times and 52.7 times higher than that in the uncontaminated soils, respectively. However, water soluble Cr (Ⅵ) contents in soils near sewer channel are all low and the values are close to that in the uncontaminated soils. Although water soluble Cr (Ⅵ) content in soil profiles decreases with soil depths, it in soils under slag heap maintains a high level even at a depth of 100-150 cm. The results imply that the transportation of Cr (Ⅵ) can result in a potential risk of groundwater system in this area.

  10. Use of copper slag in the manufacture of Portland cement

    Aquilar Elguézabal, A.


    Full Text Available Given its chemical and mineralogical characteristics, copper slag, a solid industrial by-product, may serve as a partial substitute for silica and hematite in raw mixes used to manufacture Portland cement clinker. The benefits of such substitution include lower production costs and energy savings. The effect of slag-containing raw mixes on the reactivity of the CaO-Si02-Al203-Fe203 system was studied at three temperatures (1,350, 1,400 and 1,450ºC. Four mixes were used: M-1 and M-2 prepared with conventional prime materials and M-3 and M-4, in which ignimbrite and hematite were substituted for slag. In M-3 the slag replaced 45.54% of the ignimbrite and 100% of the hematite, and in M-4 100% of the mineral iron. The samples were clinkerized at 1,350, 1,400 and 1,450ºC. At 1,400ºC, clinker M-3 was found to have 10.7% less free lime than M-1, while the level in M-4 it was 15.93% lower than in M-2. The presence of the main clinker phases was confirmed by X-ray diffraction, which also showed that adding slag during c/inker manufacture slightly improves raw mix burnability without generating new unwanted phases. Consequently, recovery in cement kilns would appear to be an economically and environmentally feasible alternative to coprocessing such waste, although the industrial use of slag depends on its heavy metal content.En acuerdo con las características químicas y mineralógicas de la escoria de cobre, este residuo sólido industrial puede ser utilizado en el proceso de fabricación de clínker Portland como sustituto parcial de los minerales de sílice y hematita en la formación de mezclas crudas cuyos beneficios serían: disminución de los costos de producción de mezclas crudas y del consumo calorífico. El efecto de la adición de la escoria en las mezclas crudas sobre la reactividad del sistema CaO-Si02-Al203-Fe20 3 se estudió en tres niveles de temperatura (1.350, 1.400 Y 1.450ºC. Se trabajó con cuatro mezclas crudas, M-1 y M

  11. Clara Maass, yellow fever and human experimentation.

    Chaves-Carballo, Enrique


    Clara Louise Maass, a 25-year-old American nurse, died of yellow fever on August 24, 1901, following experimental inoculation by infected mosquitoes in Havana, Cuba. The human yellow fever experiments were initially conducted by MAJ Walter Reed, who first used written informed consent and proved the validity of Finlay's mosquito-vector hypothesis. Despite informed consent form and an incentive of $100 in U.S. gold, human subjects were exposed to a deadly virus. The deaths of Clara Maass and two Spanish immigrants resulted in a public outcry and the immediate cessation of yellow fever human experiments in Cuba.

  12. Hippocrates, cardiology, Confucius and the Yellow Emperor.

    Cheng, T O


    Although Hippocrates (460-c.375 BC) has been traditionally recognized as the Father of Medicine, the fact that he was seminal in the development of cardiology is much less well known. Evidence is presented to support the notion that Hippocrates could also be considered the Father of Cardiology. Hippocrates also had many of the teachings and practices in common with Confucius (c.551-c.479 BC) and the Yellow Emperor of China (2695-2589 BC). Whereas Confucius was not a physician, the Yellow Emperor was an ancient Chinese physician whose Huang Di Neijing, the Yellow Emperor's Canon of Internal Medicine, is the oldest known treatise of medicine in existence.

  13. Bioavailability of Phosphorus in Two Cultivars of Pea for Broiler Chicks.

    Woyengo, T A; Emiola, I A; Kim, I H; Nyachoti, C M


    The aim was to determine the relative bioavailability of phosphorus (P) in peas for 21-day old broiler chickens using slope-ratio assay. One hundred and sixty eight male Ross 308 broiler chicks were divided into 42 groups 4 balanced for body weight and fed 7 diets in a completely randomized design (6 groups/diet) from day 1 to 21 of age. The diets were a corn-soybean meal basal diet, and the corn-soybean meal basal diet to which monosodium phosphate, brown- or yellow-seeded pea was added at the expense of cornstarch to supply 0.5% or 1% total phosphorus. Monosodium phosphate was included as a reference, and hence the estimated bioavailability of P in pea cultivars was relative to that in the monosodium phosphate. Birds and feed were weighed weekly and on d 21 they were killed to obtain tibia. The brown-seeded pea contained 23.4% crude protein, 0.47% P, whereas the yellow-seeded pea contained 24.3% crude protein and 0.38% P. Increasing dietary P supply improved (ppeas obtained using final body weight, average daily gain, tibia ash, and bone mineral density were 31.5% and 36.2%, 35.6% and 37.3%, 23.0% and 5.60%, and 40.3% and 30.3%, respectively. The estimated relative bioavailability of p values for brown- and yellow-seeded peas did not differ within each of the response criteria measured in this study. In conclusion, the relative bioavailability of P in pea did not differ depending on the cultivar (brown- vs yellow-seed). However, the relative bioavailability of P in pea may vary depending on the response criterion used to measure the bioavailability.

  14. The thermodynamic behavior of sulfur in BaO-BaF2 slags

    Rachev, Ivan P.; Tsukihashi, Fumitaka; Sano, Nobuo


    A gas-slag-metal equilibration technique was used to determine the sulfide capacity of the BaO-BaF2 system at 1473 and 1573 K. The dependence of carbonate capacity on the slag composition was also measured at these temperatures. It was found that the BaO-BaF2 system has the highest sulfide capacities among the fluxes which are of metallurgical interest. The dependence of sulfide and carbonate capacities on the partial pressure of O2 and CO2 was also investigated. The partial pressure of CO2 proved to have a strong effect on these values at the investigated temperatures. The influence of temperature on the sulfide and carbonate capacities was studied in the temperature range between 1423 and 1623 K. The data for sulfide and carbonate capacities were correlated in order to check if the carbonate capacity can be used as a measure of basicity of slags. It was found that the carbonate capacity can be used as a representative measure of the slag basicity at low contents of BaO and at temperatures higher than 1623 K when the carbonate dissolution into the slag is low and the ratio of the activity coefficient of a sulfide ion to that of a carbonate ion is independent of slag composition.

  15. Studies on use of Copper Slag as Replacement Material for River Sand in Building Constructions

    Madheswaran, C. K.; Ambily, P. S.; Dattatreya, J. K.; Rajamane, N. P.


    This work focuses on the use of copper slag, as a partial replacement of sand for use in cement concrete and building construction. Cement mortar mixtures prepared with fine aggregate made up of different proportions of copper slag and sand were tested for use as masonry mortars and plastering. Three masonry wall panels of dimensions 1 × 1 m were plastered. The studies showed that although copper slag based mortar is suitable for plastering, with the increase in copper slag content, the wastage due to material rebounding from the plastered surfaces increases. It is therefore suggested that the copper slag can be used for plastering of floorings and horizontal up to 50 % by mass of the fine aggregate, and for vertical surfaces, such as, brick/block walls it can be used up to 25 %. In this study on concrete mixtures were prepared with two water cement ratios and different proportions of copper slag ranging from 0 % (for the control mix) to 100 % of fine aggregate. The Concrete mixes were evaluated for workability, density, and compressive strength.

  16. Remediation of TCE-contaminated groundwater using acid/BOF slag enhanced chemical oxidation.

    Tsai, T T; Kao, C M; Wang, J Y


    The objective of this study was to evaluate the potential of applying acid/H(2)O(2)/basic oxygen furnace slag (BOF slag) and acid/S(2)O(8)(2-)/BOF slag systems to enhance the chemical oxidation of trichloroethylene (TCE)-contaminated groundwater. Results from the bench-scale study indicate that TCE oxidation via the Fenton-like oxidation process can be enhanced with the addition of BOF slag at low pH (pH=2-5.2) and neutral (pH=7.1) conditions. Because the BOF slag has iron abundant properties (14% of FeO and 6% of Fe(2)O(3)), it can be sustainably reused for the supplement of iron minerals during the Fenton-like or persulfate oxidation processes. Results indicate that higher TCE removal efficiency (84%) was obtained with the addition of inorganic acid for the activation of Fenton-like reaction compared with the experiments with organic acids addition (with efficiency of 10-15% lower) (BOF slag=10gL(-1); initial pH=5.2). This could be due to the fact that organic acids would compete with TCE for available oxidants. Results also indicate that the pH value had a linear correlation with the observed first-order decay constant of TCE, and thus, lower pH caused a higher TCE oxidation rate.

  17. Methods for Improving Volume Stability of Steel Slag as Fine Aggregate

    LUN Yunxia; ZilOU Mingkai; CAI Xiao; XU Fang


    Suitable methods for enhancing the volume stability of steel slag utilized as fine aggregate were determined. The effects of steam treatment at 100 ℃ and autoclave treatment under 2.0 Mpa on the soundness of steel slag sand were investigated by means of powder ratio, linear expansion, compressive and flexural strength. DTA, EDX, XRD and ethylene glycol methods were employed to analyze both the treated slags and susceptible expansion grains. Experimental results indicate that powder ratio, content of free lime and rate of linear expansion can express the improvement in volume stability of different treated methods. Steam treatment process cannot ultimately prevent specimens from cracking and decrease of strength, but mortar made from autoclave treated slag keeps integration subjected to hot water of 80 ℃ until 28 d and its strength do not show significant decrement. The hydration of over-burn free lime and periclase phase are the main cause for the disintegration or crack of untreated and steam treated steel slag's specimens. Autoclave treatment process is more effective than steam treatment process on enhancement of volume stability of steel slag.

  18. The composition and temperature dependence of the sulfide capacity of metallurgical slags

    Sosinsky, Nd. J.; Sommerville, I. D.


    The concept of optical basicity and its applicability as a means of correlating the available data on the sulfide capacity of metallurgical slags has been reviewed. An excellent correlation based on very extensive data at 1500 °C, which was discussed in a previous paper, is combined with good correlations based on considerably less data at 1550 °C and 1650 °C to quantify the effect of temperature on the sulfide capacity of slags. The combined effects of slag composition and temperature have been expressed in the equation, log C s = [(22690 - 54640A)/7] + 43.6A - 25.2. Use of this equation permits the calculation of the sulfide capacity of a slag at any temperature between 1400 °C and 1700 °C simply from a knowledge of its chemical composition, and can be employed for virtually any oxide slag of interest in the field of iron and steelmaking. This, in turn, permits calculation of the equilibrium distribution of sulfur between this slag and iron or steel, provided that the oxygen potential is known or can be calculated from the degree of deoxidation applied.

  19. Disposal of High-Temperature Slags: A Review of Integration of Heat Recovery and Material Recycling

    Sun, Yongqi; Zhang, Zuotai


    Nowadays with the continuous urbanization in China, the carbon emission and resource shortage have been serious issues, for which the disposal of blast furnace slags (BFS) and steel slags (SS) discharged from the metallurgical industry make up a significant strategy. The output of crude steel reached 823 Mt in China in 2014 and the thermal heat in these slags was equivalent to ~18 Mt of standard coal. Herein, the recent advances were systemically reviewed and analyzed, mainly from two respects, i.e., integration of heat recovery and material recycling and crystallization control of the slags. It was first found that for the heat recovery from BFS, the most intensively investigated physical method and chemical method were centrifugal granulation and gasification reaction, respectively. Furthermore, a two-step approach could contribute to a promising strategy for the treatment of slags, i.e., the liquid slags were first granulated into small particles, and then other further treatment was performed such as gasification reaction. With regard to SS, the effective disposal could be achieved using a selective crystallization and phase separation (SCPS) method, and moreover, the solid solution of 2CaO·SiO2 and the target phases could act as a promising enriched phase to extract the valuable elements.

  20. Effect of copper slag recovery on hydrometallurgical cut-off grades considering environmental aspects



    Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issues in hydrometallurgical cut-off grades determination. Slags are remarked as one of the main sources of copper. It is not only regarded as a waste but also identified as another resource extracting base metals. Slags are characterized by copper high grade. Thus, slag copper recovery can be led to different cut-off grades and net present value (NPV). The current research scrutinizes the effect of slag recovery by both flotation and hydrometallurgical methods on the hydrometallurgical cut-off grades. For this purpose, the optimum cut-off grade algorithms of hydrometallurgical methods are developed by considering associated environmental parameters, incomes and also the costs. Then, their optimum amounts are calculated with NPV maximization as an objective function. The results indicate that considering slag copper recovery in the hydrometallurgical cut-off grade algorithms reduces the environmental costs caused by slag dumping and leads to more NPV by 9%.

  1. Bioleaching of metals from steel slag by Acidithiobacillus thiooxidans culture supernatant.

    Hocheng, Hong; Su, Cheer; Jadhav, Umesh U


    The generation of 300–500 kg of slag per ton of the steel produced is a formidable amount of solid waste available for treatment. They usually contain considerable quantities of valuable metals. In this sense, they may become either important secondary resource if processed in eco-friendly manner for secured supply of contained metals or potential pollutants, if not treated properly. It is possible to recover metals from steel slag by applying bioleaching process. Electric arc furnace (EAF) slag sample was used for bioleaching of metals. In the present study, before bioleaching experiment water washing of an EAF slag was carried out. This reduced slag pH from 11.2 to 8.3. Culture supernatants of Acidithiobacillus thiooxidans (At. thiooxidans), Acidithiobacillus ferrooxidans (At. ferrooxidans), and Aspergillus niger (A. niger) were used for metal solubilization. At. thiooxidans culture supernatant containing 0.016 M sulfuric acid was found most effective for bioleaching of metals from an EAF slag. Maximum metal extraction was found for Mg (28%), while it was least for Mo (0.1%) in six days. Repeated bioleaching cycles increased metal recovery from 28% to 75%, from 14% to 60% and from 11% to 27%, for Mg, Zn and Cu respectively.

  2. Synthesis of steel slag ceramics:chemical composition and crystalline phases of raw materials

    Li-hua Zhao; Wei Wei; Hao Bai; Xu Zhang; Da-qiang Cang


    Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite,α-quartz, magnetite, and pyroxene crystals (augite and diopside) in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA) results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag.

  3. Reduction of molybdenum oxide from steelmaking slags by pure liquid iron

    Gao Y.M.


    Full Text Available The effects of reaction temperature, slag basicity and FeO concentration on the reduction of molybdenum oxide from steelmaking slags by pure liquid iron were investigated experimently. The reduction kinetics of molybdenum oxide by liquid iron was analysed. The reaction models were developed based on the condition that diffusion of [Mo] in liquid iron and CaMoO4 in slag is the control steps, respectively. These reaction models were tested using data from a series of experiments. The results indicate that under the present experimental conditions, the temperature and the FeO content, other than slag basicity, have some effects on the reduction of molybdenum oxide from steelmaking slags by pure liquid iron. Both the molybdenum oxide reduction rate and final reduction ratio increase with an increase of temperature and a decrease of FeO content. The diffusion of CaMoO4 in slag which dominated overall reduction process is the only one ratecontrolling step with its apparent activation energy 294 kJ/mol. The reduction of molybdenum oxide used directly as alloy additive can be further enhanced by strong stirring in the converter practice.


    H. A. Abdel-Gawwad


    Full Text Available The effect of different proportions and different reactivities of MgO on the drying shrinkage and compressive strength of alkali activated slag pastes (AAS has been investigated. The slag was activated by 6 wt.% sodium hydroxide and liquid sodium silicate at ratio of 3:3 (wt.. The different reactivities of MgOs were produced from the calcination of hydromagnesite at different temperatures (550, 1000, 1250 C. The results showed that the reactivity of magnesium oxide decreases with increasing the calcination temperature. Also, the drying shrinkage of AAS was reduced by the replacement of slag with MgOs. The highly reactive MgO accelerated the hydration of AAS at early ages. The replacement of slag with 5% MgO550 increased one day compressive strength by ~26 % while MgO1250 had little effect. A significant increase in strength was observed after 7 days in case of replacement of slag with 5 % MgO1250. The MgO reacts with slag to form hydrotalcite likephases (Ht as detected by XRD, FTIR spectroscopy, TGA/DTG analysis and SEM.

  5. Two-dimensional coupled fluid and electrodynamic calculations for a MHD DCW channel with slag layers

    Liu, B. L.


    A fully coupled, two dimensional numerical method of modeling linear, coal-fired MHD generators is developed for the case of a plasma flow bounded by a slag layer on the channel walls. The governing partial differential equations for the plasma flow, slag layer and electrodynamics are presented and their coupling discussed. An iterative, numerical procedure employing non-uniform computational meshes and appropriate tridiagonal matrix solution schemes for the equations is presented. The method permits the investigation of the mutual plasma flow-slag layer development for prescribed wall temperatures, electrode geometry, slag properties and channel loading. In particular, the slag layer-plasma interface properties which require prior specification in an uncoupled analysis comprise part of the solution in the present approach. Results are presented for a short diagonally connected generator channel and include contour plots of the electric potential and current stream function as well as transverse and axial profiles of pertinent plasma properties. The results indicate that a thin electrode slag layer can be maintained in the presence of reasonable current density levels.

  6. Thermodynamic Properties of Lead Oxide in a Mixture of Stainless Steelmaking and Nonferrous Smelting Slags

    Maruoka, Nobuhiro; Ueda, Shigeru; Shibata, Hiroyuki; Yamaguchi, Katsunori; Kitamura, Shin-ya


    In our previous paper, a slag modification process involving the mixing of stainless steelmaking and nonferrous smelting slags was proposed for preventing the disintegration of the stainless steelmaking slag. In order to use this method, the behavior of heavy metals especially PbO contained in the nonferrous slag has to be assessed. In the present study, the activity coefficient of PbO in CaO-SiO2-FetO-Al2O3-MgO and CaO-SiO2-FetO slags saturated with iron was measured at 1673 K. The results showed that the activity coefficient of PbO increased with basicity and had a maximum value when the basicity was approximately 1.0. The equilibrium PbO content in the modified slag had a minimum value that corresponded to a mixing ratio of 0.6. The trend was similar to the change in the removal ratio of PbO observed in the previous study. Therefore, the change in the oxygen potential and the change in the activity coefficient of PbO can be considered the cause of this trend.

  7. Evaluation and Characterization of Plasma Sprayed Cu Slag-Al Composite Coatings on Metal Substrates

    S. Mantry


    Full Text Available Copper slag is a waste product obtained during matte smelting and refining of copper. The present work explores the coating potential of copper slag by plasma spraying. This work shows that copper slag is eminently coatable. An attempt has been made in the present investigation to use the composites coatings of copper slag and Al powder in suitable combination on aluminium and mild steel substrates in order to improve the surface properties of these ductile metal-alloy substrates. When premixed with Al powder, the coating exhibits higher interfacial adhesion as compared to pure copper slag coatings. Maximum adhesion strengths of about 23 MPa and 21 MPa are recorded for the coatings of copper slag with 15 wt% of Al on aluminium and mild steel substrates, respectively. The input power to the plasma torch is found to affect the coating deposition efficiency and morphology of the coatings. It also suggests value addition of an industrial waste.

  8. Synthesis and Characterization of Titanium Slag from Ilmenite by Thermal Plasma Processing

    Samal, Sneha


    Titanium rich slag has emerged as a raw material for alternative titanium source. Ilmenite contains 42-50% TiO2 as the mineralogical composition depending on the geographical resources. Application of titanium in paper, plastic, pigment and other various industries is increasing day by day. Due to the scarcity of natural raw mineral rutile (TiO2), ilmenite is considered as precursor for the extraction of TiO2. Ilmenite is reduced at the initial stage for the conversion of complex iron oxide into simpler form. Therefore, pre-reduction of ilmenite concentrate is essential to minimize the energy consumption during thermal plasma process. Thermal plasma processing of ilmenite for the production of titania rich slag is considered to be the direct route to meet the current demand of industrial needs of titanium. Titania rich slag contains 70-80% TiO2 as the major component with some other minor impurities, like oxide phases of Si, Al, Cr, Mg, Mn, Ca, etc. Usually titanium is present in tetravalent forms with globular metallic iron in the slag. Titania rich slag undergoes leaching for the removal of iron and transforming the slag into synthetic rutile having 85-95% of TiO2.

  9. LATS refining ladle slag modifying with CaO-CaF2

    Hongming Wang; Guirong Li; Zhongming Ren; Bo Li; Xuejun Zhang; Guomin Shi


    To reduce the slag sticking onto the snorkel of the ladle during the ladle alloying treatment station (LATS) process, CaO-CaF2 (the mass ratio of CaO/CaF2 is 1:1) was employed as the modifier of the LATS refining ladle slag. The effect of CaO-CaF2 on the melting point, viscosity, and desulfurizing capability of the ladle slag was investigated. The melting point of the unmodified ladle slag is 1439°C. When adding 20wt% CaO-CaF2, the melting point is decreased to 1327°C. At 1500°C, the viscosity of the unmodified ladle slag is 6.5 Pa·s, which can be decreased lower than 2 Pa·s by adding more than 10wt% CaO-CaF2. The experimental results of desulfurization of the melts show that the desulfurizing power of the ladle slag can be enhanced by adding CaO-CaF2.

  10. Effects of Steel Slag Powder on Workability and Durability of Concrete

    GUO Xiaolu; SHI Huisheng; WU Kai


    The workability and durability of a type of sustainable concrete made with steel slag powder were investigated. The hydrated products of cement paste with ground granulated blast furnace slag (GGBFS) alone or with a combined admixture of GGBFS-steel slag powder were investigated by X-ray diffraction (XRD). Furthermore, the mechanism of chemically activated steel slag powder was also studied. The experimental results showed that when steel slag powder was added to concrete, the slumps through the same time were lower. The initial and final setting times were slightly retarded. The dry shrinkages were lower, and the abrasion resistance was better. The chemically activated steel slag powder could improve compressive strengths, resistance to chloride permeation and water permeation, as well as carbonization resistance. XRD patterns indicated that the activators enhanced the formation of calcium silicate hydrate(C-S-H) gel and ettringite (AFt). This research contributes to sustainable disposal of wastes and has the potential to provide several important environmental benefits.

  11. Theoretical and Experimental on Carbon Dioxide Sequestration Degree of Steel Slag

    LI Jian-li; ZHANG Hui-ning; XU An-jun; CUI Jian; HE Dong-feng; TIAN Nai-yuan


    The limitation and experimental CO2 sequestration degree of steel slag is the focus. The theoretical and the practical COe sequestration degree was assessed under mild operating conditions. After calculation in theory, it can be found that the CO2 sequestration limitation degree for every kilogram steel slag is about 442 g when taking magne- sium into consideration, and the experimental CO2 sequestration degree for every kilogram slag is about 77 g, under the conditions that the liquid to solid ratio is 50 L/kg, CO2 flow is 0.5 L/min and the temperature of reaction is the ambient temperature. When solution NH4Cl and CHa COOH for experiments and other conditions keep the same, the actual potential CO2 sequestration for every kilogram slag is 69.3 g and 31.20 g respectively. Thus, optimization of process parameters like granularity of slag is necessary to enhance the carbon dioxide sequestration degree for steel slag.

  12. Steel Slag and Shredded Tires as Media for Blind Inlets to Improve Water Quality

    Gonzalez, J. M.; Smith, D. R.; Livingston, S.


    Off-site transport of contaminants through surface runoff affects water quality. Blind inlets are proven conservation practices for reducing surface runoff, and consequently reducing nutrient loadings from small agricultural closed depressions to water bodies. Gravel is the most widely used blind inlet media to reduce flow, but not to sorb contaminants from the water. Readily available byproducts, such as steel slag and shredded tires, could be used as alternative media in blind inlets to sorb nutrients and pesticides from surface runoff. Sorption isotherms were performed to investigate the sorption capabilities of steel slag and shredded tires for phosphate and atrazine in electrolyte background solutions containing either 10 mM CaCl2 or KCl. Results of this research demonstrated that phosphate and atrazine were irreversibly sorbed by the steel slag and shredded tires. The steel slag increased the pH solution increased about 4 pH units after the sorption step; while the pH of the solution with shredded tires remained the same. Desorption of the phosphate and atrazine was low from the steel slag and shredded tires, respectively. Thus, the above results suggest that the steel slag and shredded tires can potentially be used as media to sorb phosphate and atrazine, respectively.

  13. [Removal of metal ions Cu2+, Cd+ and Pb+ from solutions by sorption on slag].

    Chen, Xiao; Hou, Wen-hua; Wang, Qun-hui


    Batch experiments were carried out to investigate the adsorption kinetics and thermodynamic characteristics of heavy metal ions Cu2+, Cd2+ and Pb2+ on the electric are furnace (EAF) slag from Baoshan Steel Factory. Several kinds of techniques including XRD analysis, BET specific surface analysis and SEM/EDS analysis were employed to determine the physico-chemical and surface characteristics of slag. Results indicated that the adsorption rate of heavy metal ions on the EAF slag was relatively high, and the sorption rate followed the order Cd2+ > Pb2+ > Cu2+. The adsorption kinetics obeyed first-order kinetics model (R2 > 0.99). Adsorption isotherm experiment showed that adsorption isotherm of heavy metal ions on slag fitted Langmuir model, and the maximum adsorption capacity of Cu2+, Cd2+ and Pb2+ was 0.101, 0.058 and 0.120 mmol x g(-1), respectively. The adsorption of heavy metal ions on slag was a spontaneous reaction (deltaG0 0). The effect of enthopy was the main driving force of the spontaneous adsorption reaction. The analysis results of SEM/EDS revealed the changes of surface morphology and chemical proportion before and after adsorption. Due to low-cost and high-efficiency, electric are furnace slag showed great potential for the treatment of heavy metal polluted wastewaters.

  14. Maximum availability and mineralogical control of chromium released from AOD slag.

    Li, Junguo; Liu, Bao; Zeng, Yanan; Wang, Ziming; Gao, Zhiyuan


    AOD (argon oxygen decarburization) slag is the by-product in the stainless steel refining process. Chromium existing in AOD slag can leach out and probably poses a serious threat to the environment. To assess the leaching toxicity of chromium released from AOD slag, the temperature-dependent maximum availability leaching test was performed. To determine the controlling mineralogical phases of chromium released from AOD slag, a Visual MINTEQ simulation was established based on Vminteq30 and the FactSage 7.0 database. The leaching tests indicated that the leaching availability of chromium was slight and mainly consisted of trivalent chromium. Aging of AOD slag under the atmosphere can oxidize trivalent chromium to hexavalent chromium, which could be leached out by rainwater. According to the simulation, the chromium concentration in leachates was controlled by the freely soluble pseudo-binary phases in the pH = 7.0 leaching process and controlled by the Cr2O3 phase in the pH = 4.0 leaching process. Chromium concentrations were underestimated when the controlling phases were determined to be FeCr2O4 and MgCr2O4. Facilitating the generation of the insoluble spinel-like phases during the cooling and disposal process of the molten slag could be an effective approach to decreasing the leaching concentration of chromium and its environmental risk.

  15. An Overview of Use of Linz-Donawitz (LD Steel Slag in Agriculture

    Sasmita Chand


    Full Text Available Slag generated from basic oxygen furnace (BOF or Linz-Donawitz (LD converter is one of the recyclable wastes in integrated steel plants. This paper deals with the present and possible use of LD slag in agriculture. At present, the amount of slag deposited in storage yard, leading to the occupation of farm land and serious pollution to the environment. Improving the slag utilization is an important way to resolve these problems. The physical and chemical characteristics of steel slag were analyzed and then the research progress of steel slag utilization in agriculture as fertilizer introduced. Due to increasing awareness of the environment, disposal, reuse of wastes without harming the environment has became a prime concern for the industry. The local availability of non conventional sources of plant nutrients and soil conditioners plays a vital role because of the non availability and higher price of environmental fertilizers. Therefore, this waste can be utilized for enhancing yield as well as solving the disposal problem and improve the environment.

  16. Basic Oxygen Furnace Slag as a Liming Agent for Paddy and Upland Field Soils

    Lee, Choong Il [Pohang Research Institute of Industrial Science and Technology, Pohang(Korea)


    Basic oxygen furnace (BOF) slag, a by-product of the iron and steelmaking industry produced in large quantities in Korea, poses a substantial disposal challenge. The BOF slag used in this study was 1/3 CaCO{sub 3} in total neutralizing power and application of 7-8 Mgha{sup -1} was needed to bring soil pH to 6.5 from pH 5.0-5.5 in silty clay or clay loam soil contained about 10% organic matter. A field assay was conducted to study whether BOF slag could be used as a dolomitic liming agent for agricultural soils. Four slag rates (0, 4, 8, 12 Mgha{sup -1})were investigated for their effect on soil properties, mineral concentrations in leaf tissues of rice and soybean, and yield of the crops. Slag application at 8 Mgha{sup -1} rate in paddy field increased pH, Ca, Mg, P, Si and Fe content in soil and rice yield by 4.3-14.2% depending on the soil type. In upland field the 8 Mgha{sup -1} rate increased pH, Ca and Fe content in soil and soybean yield by 36.6%. Thus, BOF slag appears to be a useful liming material for correcting soil acidity on both paddy and upland field soils and for increasing Ca, Mg, P, Si, and Fe concentration in plants. (author). 27 refs., 7 tabs.

  17. Effect of Temperature and Graphite Immersion Method on Carbothermic Reduction of Fayalite Slag

    Mitrašinović, Aleksandar


    In this work, graphite flakes were used to reduce fayalite slag originated from the pyrometallurgical copper extraction process. Experiments were conducted with a significantly different contact area between graphite and slag at two temperatures, 1300°C and 1400°C. The process was continuously monitored via the concentration change of CO and CO2 in off-gas. Reduction rate values in experiments where 150-micron-diameter graphite flakes were submerged into the slag and left to float slowly to the top are about four times higher compared with when graphite flakes were dispersed at the top surface of liquid slag. The activation energy for instigating reduction was 302.61 kJ mol-1 and 306.67 kJ mol-1 in the case where graphite flakes were submerged into the slag and dispersed at the surface, respectively. The reduction process is characterized by two distinctive periods: an initial steep increase in the concentration of CO and CO2 controlled by the Boudouard reaction and a subsequent slow decrease of CO and CO2 concentrations in the off-gas controlled by mass transfer of reducible oxides from bulk to the gas-slag interface.

  18. Slagging characteristics of molten coal ash on silicon-aluminum combustion liners of boiler


    In order to study the slagging characteristics of boiler combustion liners during pulverized coal stream combustion,the slag samples on the surface of combustion liner were investigated by X-ray diffractometry,scan electron microscopy and energy dispersive X-ray analysis,and the transformation characteristics of the compositions and crystal phases were studied.The results show that the size of slag granules decreases as the slagging temperature increases;the crystallinity of coal ash I reduces to about 48.6% when the temperature is increased up to 1 350 ℃,and that of the coal ash Ⅱ reduces to about 65% when the temperature is increased up to 1 500 ℃;the encroachment of molten coal ash to the combustion liner is strengthened.At the same time,the diffusion and the segregation of the compositions in combustion liners have selectivity,which is in favor of enhancing the content of crystal phases,weakening the conglutination among molten slag compositions and combustion liner,and avoiding yielding big clinkers.But the diffusion of the compositions in combustion liners increases the porosity and decreases the mechanical intensity of combustion liner,and makes the slag encroachment to the liner become more serious.

  19. Adsorption Study of Electric Arc Furnace Slag for the Removal of Manganese from Solution

    C. L. Beh


    Full Text Available Problem statement: Steel making slag from Electric Arc Furnace (EAF is an abundant by-product in Malaysia steel making industry. It has potential to be used for heavy metal removal from contaminated water or waste water. Approach: The aim of this study was to investigate the characteristic and behavior of manganese removal by using EAF slag for efficient metal removal. The removal characteristics of manganese were investigated in term of sorption kinetics and isotherm. The batch adsorption kinetics and isotherm studies were carried out at 28°C and ten grams of EAF slag was added into 1 L manganese solution of various concentrations of 10, 25, 50, 75, 100 and 120 mg L-1. All these different mixtures were stirred and sampled at various desired times and centrifuged. The supernatant solutions were then collected for chemical analysis. Results: It was found that the EAF slag adsorption kinetics can be described well by the pseudo-2nd order kinetic model with fairly high correlation coefficients. The adsorption process obeyed the Langmuir isotherm model and the maximum uptake of the manganese from the solution is 2.31 mg L-1 g-1 of EAF slag used. Conclusion: From the study, it was concluded that the EAF slag can be an efficient adsorbent to remove manganese from both the solution and waste water.

  20. Analyzing the Technology of Using Ash and Slag Waste from Thermal Power Plants in the Production of Building Ceramics

    Malchik, A. G.; Litovkin, S. V.; Rodionov, P. V.; Kozik, V. V.; Gaydamak, M. A.


    The work describes the problem of impounding and storing ash and slag waste at coal thermal power plants in Russia. Recovery and recycling of ash and slag waste are analyzed. Activity of radionuclides, the chemical composition and particle sizes of ash and slag waste were determined; the acidity index, the basicity and the class of material were defined. The technology for making ceramic products with the addition of ash and slag waste was proposed. The dependencies relative to the percentage of ash and slag waste and the optimal parameters for baking were established. The obtained materials were tested for physical and mechanical properties, namely for water absorption, thermal conductivity and compression strength. Based on the findings, future prospects for use of ash and slag waste were identified.