The mechanisms of aid-leaching reagent calcium fluoride in the extracting vanadium processes were researched by comparing the blank extraction with the extraction with calcium fluoride as aid-leaching reagent. The lea...The mechanisms of aid-leaching reagent calcium fluoride in the extracting vanadium processes were researched by comparing the blank extraction with the extraction with calcium fluoride as aid-leaching reagent. The leaching experiments were carried out under the conditions of 95 ~C, 6 h, 1.5 ml.g-1, 15 vol % H2SO4, and 5 % calcium fluoride (mass ratio of CaF2 to stone coal). The concentrations of hydrogen ion were adjusted from initial 1.82 and 4.79 mol.L-1 to the pH of 1.80 4- 0.05 by 200 g.L-1 lime milk, respectively. The solvent extraction experiments were carded out under the organic phase using 15 vol% D2EHPA, 5 vol% TBP, and 80 vol% sulfonated kerosene and O/A phase ratio of 1/4. The leaching rate of vanadium and six-stage countercurrent solvent extraction rate of vanadium can be remarkably improved from 66.71 to 92.97 % and 81.15 to 98.81%, respectively, when calcium fluoride was added as aid-leaching reagent. In the leaching process, fluorine can enhance the breakage of the structure of vanadium-bearing minerals. Meanwhile, fluoride ion can combine with iron ion to generate acid-insoluble iron fluoride hydrate (Fe2Fs.7H20) and consume all ferric ions and a portion of ferrous ions. In adjusting pH value process, the massive impurities are decreased to form KA1SO4 and FeA1Fs. In solvent extraction process, fluorine can prevent the formation of ferric hydroxide colloids and eliminate the formed unstable ferric hydroxide colloids and the silicon-containing colloids to promote the sufficient contact between the aqueous phase and the organic phase and the sufficient reaction.展开更多
The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when...The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 moUL H2SO4 at 90℃ for 2 h. After the sample is roasted at 900℃ for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the Content of V(V) increases with the rise of roasting temperature from 600 to 900℃, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000℃. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.展开更多
The low-grade vanadium-containing stone coal used in this experiment was collected from Wuxi Country, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through optimizing the ...The low-grade vanadium-containing stone coal used in this experiment was collected from Wuxi Country, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through optimizing the process conditions of an effective and environmentally-friendly technology, named calcified roasting-sulfuric acid leaching technology. By single-factor experiments and orthogonal experiments, the effects of roasting temperature, roasting time, sulfuric acid concentration and leaching time on the leaching ratio of vanadium were analyzed. The results showed that the leaching ratio of vanadium reached 85.5% under the proper technological conditions of roasting temperature=950℃, roasting time=4 h, 40% concentration of sulfuric acid and leaching time=6 h.展开更多
The effects of roasting, mass ratio of H2SO4 to stone coal, leaching temperature, liquid-to-solid ratio, grinding fineness of stone coal, and two-stage counter-current leaching on the vanadium leaching ratio were stud...The effects of roasting, mass ratio of H2SO4 to stone coal, leaching temperature, liquid-to-solid ratio, grinding fineness of stone coal, and two-stage counter-current leaching on the vanadium leaching ratio were studied. The results show that the vanadium leaching ratio of roasted stone coal through two-stage counter-current leaching can reach 65.1% at the mass ratio of H2SO4 to stone coal of 20%, leaching temperature of 95℃, leaching time of 30 h, liquid-to-solid ratio of 1.1 mL·g^-1, and grinding fineness of 0.1 mm, which can serve as an experimental basis for the production of vanadium from stone coal.展开更多
In order to reduce the pollution of Cl2 and HCl released during extracting vanadium from stone coal by sodium chloride roasting, a modified salt-roasting process was proposed by adding calcined lime in roasting proces...In order to reduce the pollution of Cl2 and HCl released during extracting vanadium from stone coal by sodium chloride roasting, a modified salt-roasting process was proposed by adding calcined lime in roasting process followed by H2SO4 leaching. The effects of parameters including roasting temperature, roasting time, addition mass ratio of NaCl, calcined lime upon leaching rate of vanadium and curing rate of chlorine were investigated, and the effects of leaching time and leaching temperature on leaching rate of vanadium were also studied. The results show that the vanadium leaching rate and the curing rate of chlorine are 67.3% and 51.5% (mass fraction), respectively, at roasting temperature of 750 °C, roasting time of 4 h, 15% sodium chloride and 8% (mass fraction) calcined lime, leaching temperature of room temperature, and leaching time of 4 h.展开更多
Experiments comparing microwave blank roasting and conventional blank roasting for typical vanadium-bearing stone coal from Hubei Province in central China, in which vanadium is present in muscovite, were conducted to...Experiments comparing microwave blank roasting and conventional blank roasting for typical vanadium-bearing stone coal from Hubei Province in central China, in which vanadium is present in muscovite, were conducted to investigate the effects of roasting tempera- ture, roasting time, H2SO4 concentration, and leaching time on vanadium extraction. The results show that the vanadium leaching efficiency is 84% when the sample is roasted at 800℃ for 30 min by microwave irradiation and the H2SO4 concentration, liquid/solid ratio, leaching temperature, and leaching time are set as 20vo1%, 1.5:1 mL.g-1, 95℃, and 8 h, respectively. However, the vanadium leaching efficiency achieved for the sample subjected to conventional roasting at 900℃ for 60 min is just 71% under the same leaching conditions. Scanning electron microscopy (SEM) analysis shows that the microwave roasted samples contain more cracks and that the particles are more porous compared to the conventionally roasted samples. According to the results of X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses, neither of these roasting methods could completely destroy the mica lattice structure under the experimental conditions; however, both methods deformed the muscovite structure and facilitated the leaching process. Comparing with conventional roasting, microwave roasting causes a greater deformation of the mineral structure at a lower temperature for a shorter roasting time.展开更多
A new process of extracting vanadium from the stone coal vanadium ore in Fangshankou, Dtmhuang area of Gansu Province, China was introduced. Various leaching experiments were carried out, and the results show that the...A new process of extracting vanadium from the stone coal vanadium ore in Fangshankou, Dtmhuang area of Gansu Province, China was introduced. Various leaching experiments were carried out, and the results show that the vanadium ore in Fangshankou is difficult to process due to its high consumption of acid and the high leaching rate of impurities. However, the leaching rate can be up to 80% and the content of V2O5 in the residue can be between 0.22%-0.25% in the process of ore fme grinding→oxidation roasting→mixing and ripening→aqueous leaching→P2O4 solvent extraction→sulfuric acid stripping→oxidation and precipitation→decomposition by heat. Also, the quality of flaky V205 produced by this process can meet the requirements of GB3283--87. The total leaching rate of vanadium is 70%. Also, three types of wastes are easy to treat. The vanadium extraction process is better in relation to the aspect of environmental protection than the sodium method.展开更多
An effectively new technology of extracting vanadium from stone coals by high concentration sulfuric acid was researched. The effect of the concentration of sulfuric acid,leaching temperature,leaching time and helper ...An effectively new technology of extracting vanadium from stone coals by high concentration sulfuric acid was researched. The effect of the concentration of sulfuric acid,leaching temperature,leaching time and helper leaching agent on the extraction of vanadium was explored.The results show that the optimal conditions of extraction are as follows:the concentration of sulfuric acid is 6 mol/L,the ratio of liquid to solid is 3-1;the temperature is 90℃;the leaching time is 3-5 h,the diameter of the ore particle is less than 180μm,and the concentration of helper leaching agent R is 6%.Under these conditions,the extraction of vanadium can reach 95.86%.展开更多
Vanadium extraction from stone-coal was investigated by oxygen pressure acid leaching and solvent extraction.The mineralogy of the stone-coal from Tongren City of Guizhou Province,China,was investigated by various det...Vanadium extraction from stone-coal was investigated by oxygen pressure acid leaching and solvent extraction.The mineralogy of the stone-coal from Tongren City of Guizhou Province,China,was investigated by various determination methods. The effects of leaching time,leaching temperature,leaching agent concentration,leaching L/S ratio,granularity of material,additive consumption were investigated based on the mineralogy.The results show that under the conditions of leaching time of 3-4 h, temperature of 150℃,sulfuric acid consumption of 25%?30%,ratio of liquid to solid of 1.2:1,the granularity less than 0.074 mm, additive consumption of 3%-5%,and oxygen pressure of 1.2 MPa,and the vanadium leaching rate can be more than 92%by the method of two-step pressurized acid leaching.The powdery V2O5 product with 99.52%in V2O5 content is obtained by the flowsheet of acid recovery,removing iron by reduction process,solvent extraction,precipitating vanadium with ammonium water,and pyrolysis from the stone-coal oxygen pressure acid-leaching solution.The total recovery efficiency of vanadium is above 85%,which is more than 20%higher than that obtained in the conventional process.Furthermore,the new process does not cause air pollution since no HCl or Cl2 is released by calcination of the raw material.展开更多
Through leaching from residue directly and leaching after a roasting treatment,respectively,the experimental research on sulfuric leaching of vanadium from residue of stone coal that came from power generation was con...Through leaching from residue directly and leaching after a roasting treatment,respectively,the experimental research on sulfuric leaching of vanadium from residue of stone coal that came from power generation was conducted.Factors which influence the leaching of vanadium such as concentration of sulfuric acid,leaching temperature,leaching time and liquid-to-solid ratio were investigated in both processes.In the process of direct leaching,to achieve a leaching rate of 74.49%,H2SO4 concentration of up to 5.4%,leaching temperature of 90℃and leaching time of 8 h were necessary reaction factors.The results show that after a roasting treatment at the optimum condition of 950℃at 1 h,76.88%vanadium can be leached under the experimental condition of 0.45% of H2SO4,30℃for 1 h with a liquid-to-solid ratio of 2 mL/g.Leaching after an oxidation roasting treatment is an efficient way to leach vanadium from the residue of stone coal,which has some advantages,such as high recovery,low economic cost and less impurities in leaching solution.展开更多
This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including th...This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial p H value, initial Fe^(2+) concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92 wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield(H_2SO_4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11 wt% greater than the chemical leaching yield. The Community Bureau of Reference(BCR) sequential extraction results revealed that 88.62 wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44 wt%. The X-ray diffraction(XRD) and Fourier transform infrared(FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.展开更多
The effects of reaction time,reaction temperature,stirring speed and flowrate of CO2 gas on desilication rate and loss rate of vanadium were studied.The results indicated that desilication rate increases with the incr...The effects of reaction time,reaction temperature,stirring speed and flowrate of CO2 gas on desilication rate and loss rate of vanadium were studied.The results indicated that desilication rate increases with the increase of flowrate of CO2 gas and reaction time.Reaction temperature and stirring speed have little effect on desilication rate,while influence the loss rate of vanadium significantly.Under the condition of reaction time of 2 h,reaction temperature of 95℃,stirring speed of 180 r/min,flowrate of CO2 gas of 60 mL/min and aging time of 2 h,desilication rate is more than 96%and the loss rate of vanadium is about 4.24%.The residue of desilication process can be processed for silicon materials,such as high-grade hydrated silica,which commonly known as white carbon black.In addition,with this carbonation method,leaching regents NaOH can be recycled by simple treatments.展开更多
提出一种难选石煤在空气气氛下悬浮焙烧-酸浸强化的提钒新技术。在焙烧温度为800℃、焙烧时间为20 min、气体流量为400 m L/min的条件下钒的浸出率从过去的20%提高到目前技术的47.14%。在焙烧过程中,石煤表面逐渐变得粗糙和不规则,颗粒...提出一种难选石煤在空气气氛下悬浮焙烧-酸浸强化的提钒新技术。在焙烧温度为800℃、焙烧时间为20 min、气体流量为400 m L/min的条件下钒的浸出率从过去的20%提高到目前技术的47.14%。在焙烧过程中,石煤表面逐渐变得粗糙和不规则,颗粒比表面积增加,硅酸盐矿物的片状结构被破坏,促进了钒的释放。同时,石煤中的钒被氧化为V(Ⅴ)或V(Ⅳ)。结果表明,由于悬浮焙烧过程中钒的释放和转化,因此,其浸出率得到了提高。展开更多
本研究以石煤提钒尾渣为原料制备了建筑用烧结砖,研究了石煤提钒尾渣细度及添加量对制品抗压强度及吸水率的影响,采用XRD和SEM表征手段分析了石煤提钒尾渣添加量调控烧结砖相组成与显微结构的机理,检测了制品的抗冻融性与使用安全性。...本研究以石煤提钒尾渣为原料制备了建筑用烧结砖,研究了石煤提钒尾渣细度及添加量对制品抗压强度及吸水率的影响,采用XRD和SEM表征手段分析了石煤提钒尾渣添加量调控烧结砖相组成与显微结构的机理,检测了制品的抗冻融性与使用安全性。结果表明:提高尾渣细度改善了样品的致密度与抗压强度,引入尾渣使样品的抗压强度先增大后减小。B3样品(尾渣:黏土:粉煤灰=30:30:40)经1150 o C烧成后,其抗压强度≥35 MPa,吸水率小于≤13%,综合性能满足《烧结普通砖》(GB/T 5101-2003)中Mu30的要求。XRD与SEM分析表明,添加15%~30%尾渣有利于生成液相,促进钙长石与钙黄长石的生成,晶粒与液相相互胶结,使制品具有较高的抗压强度与致密度及较好的抗冻融性能。展开更多
基金financially supported by the Key Science and Technology Support Program (No. 2011BAB05B01) from the Ministry of ScienceTechnology of China and the Special Science and Technology Program (No. 201009013) from the Ministry of Environmental Protection of China
文摘The mechanisms of aid-leaching reagent calcium fluoride in the extracting vanadium processes were researched by comparing the blank extraction with the extraction with calcium fluoride as aid-leaching reagent. The leaching experiments were carried out under the conditions of 95 ~C, 6 h, 1.5 ml.g-1, 15 vol % H2SO4, and 5 % calcium fluoride (mass ratio of CaF2 to stone coal). The concentrations of hydrogen ion were adjusted from initial 1.82 and 4.79 mol.L-1 to the pH of 1.80 4- 0.05 by 200 g.L-1 lime milk, respectively. The solvent extraction experiments were carded out under the organic phase using 15 vol% D2EHPA, 5 vol% TBP, and 80 vol% sulfonated kerosene and O/A phase ratio of 1/4. The leaching rate of vanadium and six-stage countercurrent solvent extraction rate of vanadium can be remarkably improved from 66.71 to 92.97 % and 81.15 to 98.81%, respectively, when calcium fluoride was added as aid-leaching reagent. In the leaching process, fluorine can enhance the breakage of the structure of vanadium-bearing minerals. Meanwhile, fluoride ion can combine with iron ion to generate acid-insoluble iron fluoride hydrate (Fe2Fs.7H20) and consume all ferric ions and a portion of ferrous ions. In adjusting pH value process, the massive impurities are decreased to form KA1SO4 and FeA1Fs. In solvent extraction process, fluorine can prevent the formation of ferric hydroxide colloids and eliminate the formed unstable ferric hydroxide colloids and the silicon-containing colloids to promote the sufficient contact between the aqueous phase and the organic phase and the sufficient reaction.
基金financially supported by the National Key Technologies R&D Program of China(Nos.2011BAB05B01 and 2011BAB05B04)the Exclusive Research Fund of Environmental Protection for the Commonweal of China(No.201009013)
文摘The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 moUL H2SO4 at 90℃ for 2 h. After the sample is roasted at 900℃ for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the Content of V(V) increases with the rise of roasting temperature from 600 to 900℃, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000℃. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.
基金the Scientific Research Foundation of State Key Lab.of Coal Mine Disaster Dynamics and Control(2011AD105827-MS201206)Scientific&Technologic Program for the Bureau of Land Resources and Housing Management of Chongqing
文摘The low-grade vanadium-containing stone coal used in this experiment was collected from Wuxi Country, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through optimizing the process conditions of an effective and environmentally-friendly technology, named calcified roasting-sulfuric acid leaching technology. By single-factor experiments and orthogonal experiments, the effects of roasting temperature, roasting time, sulfuric acid concentration and leaching time on the leaching ratio of vanadium were analyzed. The results showed that the leaching ratio of vanadium reached 85.5% under the proper technological conditions of roasting temperature=950℃, roasting time=4 h, 40% concentration of sulfuric acid and leaching time=6 h.
基金supported by the Science Foundation of Central South University (No. 76112037)the Postdoctoral Science Foundation of Central South University.
文摘The effects of roasting, mass ratio of H2SO4 to stone coal, leaching temperature, liquid-to-solid ratio, grinding fineness of stone coal, and two-stage counter-current leaching on the vanadium leaching ratio were studied. The results show that the vanadium leaching ratio of roasted stone coal through two-stage counter-current leaching can reach 65.1% at the mass ratio of H2SO4 to stone coal of 20%, leaching temperature of 95℃, leaching time of 30 h, liquid-to-solid ratio of 1.1 mL·g^-1, and grinding fineness of 0.1 mm, which can serve as an experimental basis for the production of vanadium from stone coal.
基金Project(2007GH001) supported by Development and Reform Commission of Guizhou Province, China
文摘In order to reduce the pollution of Cl2 and HCl released during extracting vanadium from stone coal by sodium chloride roasting, a modified salt-roasting process was proposed by adding calcined lime in roasting process followed by H2SO4 leaching. The effects of parameters including roasting temperature, roasting time, addition mass ratio of NaCl, calcined lime upon leaching rate of vanadium and curing rate of chlorine were investigated, and the effects of leaching time and leaching temperature on leaching rate of vanadium were also studied. The results show that the vanadium leaching rate and the curing rate of chlorine are 67.3% and 51.5% (mass fraction), respectively, at roasting temperature of 750 °C, roasting time of 4 h, 15% sodium chloride and 8% (mass fraction) calcined lime, leaching temperature of room temperature, and leaching time of 4 h.
基金This work was financially supported by the Science Foundation of Central South University (No.76112037)the Postdoctoral Science Foundation of Central South University.
基金financially supported by the Research Project from the Chinese Ministry of Education (No. 213025A)
文摘Experiments comparing microwave blank roasting and conventional blank roasting for typical vanadium-bearing stone coal from Hubei Province in central China, in which vanadium is present in muscovite, were conducted to investigate the effects of roasting tempera- ture, roasting time, H2SO4 concentration, and leaching time on vanadium extraction. The results show that the vanadium leaching efficiency is 84% when the sample is roasted at 800℃ for 30 min by microwave irradiation and the H2SO4 concentration, liquid/solid ratio, leaching temperature, and leaching time are set as 20vo1%, 1.5:1 mL.g-1, 95℃, and 8 h, respectively. However, the vanadium leaching efficiency achieved for the sample subjected to conventional roasting at 900℃ for 60 min is just 71% under the same leaching conditions. Scanning electron microscopy (SEM) analysis shows that the microwave roasted samples contain more cracks and that the particles are more porous compared to the conventionally roasted samples. According to the results of X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses, neither of these roasting methods could completely destroy the mica lattice structure under the experimental conditions; however, both methods deformed the muscovite structure and facilitated the leaching process. Comparing with conventional roasting, microwave roasting causes a greater deformation of the mineral structure at a lower temperature for a shorter roasting time.
文摘A new process of extracting vanadium from the stone coal vanadium ore in Fangshankou, Dtmhuang area of Gansu Province, China was introduced. Various leaching experiments were carried out, and the results show that the vanadium ore in Fangshankou is difficult to process due to its high consumption of acid and the high leaching rate of impurities. However, the leaching rate can be up to 80% and the content of V2O5 in the residue can be between 0.22%-0.25% in the process of ore fme grinding→oxidation roasting→mixing and ripening→aqueous leaching→P2O4 solvent extraction→sulfuric acid stripping→oxidation and precipitation→decomposition by heat. Also, the quality of flaky V205 produced by this process can meet the requirements of GB3283--87. The total leaching rate of vanadium is 70%. Also, three types of wastes are easy to treat. The vanadium extraction process is better in relation to the aspect of environmental protection than the sodium method.
基金Project(2007ZDGC-11)supported by"13115"Science and Technique Innovation Program of Shaanxi Province,ChinaProject(QN0918)supported by Science Fund for Young Scholars of Xi’an University of Architecture and Technology,China
文摘An effectively new technology of extracting vanadium from stone coals by high concentration sulfuric acid was researched. The effect of the concentration of sulfuric acid,leaching temperature,leaching time and helper leaching agent on the extraction of vanadium was explored.The results show that the optimal conditions of extraction are as follows:the concentration of sulfuric acid is 6 mol/L,the ratio of liquid to solid is 3-1;the temperature is 90℃;the leaching time is 3-5 h,the diameter of the ore particle is less than 180μm,and the concentration of helper leaching agent R is 6%.Under these conditions,the extraction of vanadium can reach 95.86%.
基金Project(2006AA06Z130)supported by the High-tech Research and Development Program of ChinaProject(50874053)supported by the National Natural Science Foundation of ChinaProject(2007GA010)supported by Science and Technology Bureau of Yunnan Province,China
文摘Vanadium extraction from stone-coal was investigated by oxygen pressure acid leaching and solvent extraction.The mineralogy of the stone-coal from Tongren City of Guizhou Province,China,was investigated by various determination methods. The effects of leaching time,leaching temperature,leaching agent concentration,leaching L/S ratio,granularity of material,additive consumption were investigated based on the mineralogy.The results show that under the conditions of leaching time of 3-4 h, temperature of 150℃,sulfuric acid consumption of 25%?30%,ratio of liquid to solid of 1.2:1,the granularity less than 0.074 mm, additive consumption of 3%-5%,and oxygen pressure of 1.2 MPa,and the vanadium leaching rate can be more than 92%by the method of two-step pressurized acid leaching.The powdery V2O5 product with 99.52%in V2O5 content is obtained by the flowsheet of acid recovery,removing iron by reduction process,solvent extraction,precipitating vanadium with ammonium water,and pyrolysis from the stone-coal oxygen pressure acid-leaching solution.The total recovery efficiency of vanadium is above 85%,which is more than 20%higher than that obtained in the conventional process.Furthermore,the new process does not cause air pollution since no HCl or Cl2 is released by calcination of the raw material.
基金Project(50974133)supported by the National Natural Science of Chinaproject(08zxgk06)supported by the Opening Foundation of Key Laboratory of Solid Waste Treatment and Resource Recycle(SWUST),Ministry of Education,China
文摘Through leaching from residue directly and leaching after a roasting treatment,respectively,the experimental research on sulfuric leaching of vanadium from residue of stone coal that came from power generation was conducted.Factors which influence the leaching of vanadium such as concentration of sulfuric acid,leaching temperature,leaching time and liquid-to-solid ratio were investigated in both processes.In the process of direct leaching,to achieve a leaching rate of 74.49%,H2SO4 concentration of up to 5.4%,leaching temperature of 90℃and leaching time of 8 h were necessary reaction factors.The results show that after a roasting treatment at the optimum condition of 950℃at 1 h,76.88%vanadium can be leached under the experimental condition of 0.45% of H2SO4,30℃for 1 h with a liquid-to-solid ratio of 2 mL/g.Leaching after an oxidation roasting treatment is an efficient way to leach vanadium from the residue of stone coal,which has some advantages,such as high recovery,low economic cost and less impurities in leaching solution.
基金financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2015ZX07205003)
文摘This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial p H value, initial Fe^(2+) concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92 wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield(H_2SO_4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11 wt% greater than the chemical leaching yield. The Community Bureau of Reference(BCR) sequential extraction results revealed that 88.62 wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44 wt%. The X-ray diffraction(XRD) and Fourier transform infrared(FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.
基金Project(50974133)supported by the National Natural Science Foundation of China
文摘The effects of reaction time,reaction temperature,stirring speed and flowrate of CO2 gas on desilication rate and loss rate of vanadium were studied.The results indicated that desilication rate increases with the increase of flowrate of CO2 gas and reaction time.Reaction temperature and stirring speed have little effect on desilication rate,while influence the loss rate of vanadium significantly.Under the condition of reaction time of 2 h,reaction temperature of 95℃,stirring speed of 180 r/min,flowrate of CO2 gas of 60 mL/min and aging time of 2 h,desilication rate is more than 96%and the loss rate of vanadium is about 4.24%.The residue of desilication process can be processed for silicon materials,such as high-grade hydrated silica,which commonly known as white carbon black.In addition,with this carbonation method,leaching regents NaOH can be recycled by simple treatments.
基金supported by the Fundamental Research Funds for the Central Universities (No. N2101023)the National Key Research and Development Program of China(No. 2018YFC1901901902)+1 种基金the National Natural Science Foundation of China (Nos. 51904058, 52104247, 52130406)the Open Foundation of State Key Laboratory of Mineral Processing, China (No. BGRIMM-KJSKL-2020-17)。
文摘提出一种难选石煤在空气气氛下悬浮焙烧-酸浸强化的提钒新技术。在焙烧温度为800℃、焙烧时间为20 min、气体流量为400 m L/min的条件下钒的浸出率从过去的20%提高到目前技术的47.14%。在焙烧过程中,石煤表面逐渐变得粗糙和不规则,颗粒比表面积增加,硅酸盐矿物的片状结构被破坏,促进了钒的释放。同时,石煤中的钒被氧化为V(Ⅴ)或V(Ⅳ)。结果表明,由于悬浮焙烧过程中钒的释放和转化,因此,其浸出率得到了提高。
文摘本研究以石煤提钒尾渣为原料制备了建筑用烧结砖,研究了石煤提钒尾渣细度及添加量对制品抗压强度及吸水率的影响,采用XRD和SEM表征手段分析了石煤提钒尾渣添加量调控烧结砖相组成与显微结构的机理,检测了制品的抗冻融性与使用安全性。结果表明:提高尾渣细度改善了样品的致密度与抗压强度,引入尾渣使样品的抗压强度先增大后减小。B3样品(尾渣:黏土:粉煤灰=30:30:40)经1150 o C烧成后,其抗压强度≥35 MPa,吸水率小于≤13%,综合性能满足《烧结普通砖》(GB/T 5101-2003)中Mu30的要求。XRD与SEM分析表明,添加15%~30%尾渣有利于生成液相,促进钙长石与钙黄长石的生成,晶粒与液相相互胶结,使制品具有较高的抗压强度与致密度及较好的抗冻融性能。