A novel process was developed for the decomposition of vanadium slag using KOH sub-molten salt under ambient pressure, and the effects of reaction temperature, alkali-to-ore mass ratios, particle size, and stirring sp...A novel process was developed for the decomposition of vanadium slag using KOH sub-molten salt under ambient pressure, and the effects of reaction temperature, alkali-to-ore mass ratios, particle size, and stirring speed on vanadium and chromium extraction were studied. The results suggest that the reaction temperature and KOH-to-ore mass ratio are more influential factors for the extraction of vanadium and chromium. Under the optimal reaction conditions （temperature 180 °C, initial KOH-to-ore mass ratio 4：1, stirring speed 700 r/min, gas flow 1 L/min, and reaction time 300 min）, vanadium and chromium extraction rates can reach up to 95% and 90%, respectively. Kinetics analysis results show that the decomposing process of vanadium slag in KOH sub-molten salt can be well interpreted by the shrinking core model under internal diffusion control. The apparent activation energies for vanadium and chromium are 40.54 and 50.27 kJ/mol, respectively.展开更多
Sub-molten salt was applied to the decomposition of zircon sand(ZrSiO4).The kinetics of the decomposition of zircon sand and the effects of reaction temperature,reaction time,NaOH content,agitation speed,and the NaOH/...Sub-molten salt was applied to the decomposition of zircon sand(ZrSiO4).The kinetics of the decomposition of zircon sand and the effects of reaction temperature,reaction time,NaOH content,agitation speed,and the NaOH/ore mass ratio on the decomposition rate of zircon sand in NaOH sub-molten salt were investigated.The results indicate that the decomposition rate of zircon sand increases with the increase in the reaction temperature,reaction time,and NaOH content.The shrinking-core model with surface chemical reaction-controlled process is the most applicable for the decomposition of zircon sand,with the apparent activation energy of 77.98 kJ/mol.The decomposition product is sodium zirconium silicate(Na2ZrSiO5),and the decomposition rate is higher than 99%under the optimal conditions.展开更多
Viewing the problem of high ene rgy consumption in the process of recovering rare earths from rare earth molten salt electrolysis slag,an environmentally friendly and low carbon process by sub-molten salt decompositio...Viewing the problem of high ene rgy consumption in the process of recovering rare earths from rare earth molten salt electrolysis slag,an environmentally friendly and low carbon process by sub-molten salt decomposition was developed.The thermodynamic analysis of sub-molten salt reaction indicates that the recovery of rare earths from the slag using sub-molten salt medium is thermodynamically feasible.In this process,the rare earth fluoride and lithium in the slag are almost transformed into rare earth hydroxide,sodium fluoride and lithium hydroxide,fluorine and lithium are transferred into the washing solution,and the rare earths in the residues can be leached into solution by acid leaching.Under the optimum reaction conditions of reaction temperature 200℃,reaction time 3 h,NaOH initial concentration 80%,NaOH-Slag mass ratio 3:1,the leaching efficiency of rare earths,fluorine and lithium can reach to 99.05%,98.23% and 99.22%.After evaporation,the fluorine and lithium in the washing solution can be obtained in the forms of sodium fluoride and lithium fluoride,the recovery efficiency reach 95.5%and 92.8%,respectively.The RE oxides(99.53%) can be obtained from the leaching solution after precipitation and roasting.展开更多
A series of innovative green metallurgical processes using novel reaction media including the NaOH/KOH sub-molten salt media and the NaOH-NaNO3 binary molten salt medium, for the extraction of vanadium and chromium fr...A series of innovative green metallurgical processes using novel reaction media including the NaOH/KOH sub-molten salt media and the NaOH-NaNO3 binary molten salt medium, for the extraction of vanadium and chromium from the vanadium slag have been developed. In comparison with the traditional sodium salt roasting technology, which operates at 850 ℃, the operation temperatures of these new processes drop to 200-400 ℃. Further, the extraction rates of vanadium and chromium utilizing the new approaches could reach 95% and 90%, respectively, significantly higher than those in the traditional roasting process, which are 75% and approximate zero, respectively. Besides, no hazardous gases and toxic tailings are discharged during the extraction process. Compared with the conventional roasting method, these new technologies show obvious advantages in terms of energy, environments, and the mineral resource utilization efficiency, providing an attractive alternative for the green technology upgrade of the vanadium production industries.展开更多
基金Project(2013CB632605)supported by the National Basic Research Development Program of ChinaProjects(51274178,51274179)supported by the National Natural Science Foundation of China
文摘A novel process was developed for the decomposition of vanadium slag using KOH sub-molten salt under ambient pressure, and the effects of reaction temperature, alkali-to-ore mass ratios, particle size, and stirring speed on vanadium and chromium extraction were studied. The results suggest that the reaction temperature and KOH-to-ore mass ratio are more influential factors for the extraction of vanadium and chromium. Under the optimal reaction conditions （temperature 180 °C, initial KOH-to-ore mass ratio 4：1, stirring speed 700 r/min, gas flow 1 L/min, and reaction time 300 min）, vanadium and chromium extraction rates can reach up to 95% and 90%, respectively. Kinetics analysis results show that the decomposing process of vanadium slag in KOH sub-molten salt can be well interpreted by the shrinking core model under internal diffusion control. The apparent activation energies for vanadium and chromium are 40.54 and 50.27 kJ/mol, respectively.
基金Project(51704270)supported by the National Natural Science Foundation of ChinaProject(ZDRW-ZS-2018-1)supported by the Key Research Program of Chinese Academy of SciencesProject(KFJ-STS-ZDTP-040)supported by the Science and Technology Service Network Plan of Chinese Academy of Sciences
文摘Sub-molten salt was applied to the decomposition of zircon sand(ZrSiO4).The kinetics of the decomposition of zircon sand and the effects of reaction temperature,reaction time,NaOH content,agitation speed,and the NaOH/ore mass ratio on the decomposition rate of zircon sand in NaOH sub-molten salt were investigated.The results indicate that the decomposition rate of zircon sand increases with the increase in the reaction temperature,reaction time,and NaOH content.The shrinking-core model with surface chemical reaction-controlled process is the most applicable for the decomposition of zircon sand,with the apparent activation energy of 77.98 kJ/mol.The decomposition product is sodium zirconium silicate(Na2ZrSiO5),and the decomposition rate is higher than 99%under the optimal conditions.
基金Project supported by the National Key Research and Development Project (2018YFC1903400)the Jiangxi Province Graduate Student Innovation Special Fund Project (203200800389)+2 种基金the Natural Science Foundation of Jiangxi Province (20224BAB204038,20202BAB214014)the Young Elite Scientists Sponsorship Program by CAST (2022QNRC001)the Open Project of Guangxi Key Laboratory of Nonferrous Metals and Characteristic Materials Processing(2022GXYSOF11)。
文摘Viewing the problem of high ene rgy consumption in the process of recovering rare earths from rare earth molten salt electrolysis slag,an environmentally friendly and low carbon process by sub-molten salt decomposition was developed.The thermodynamic analysis of sub-molten salt reaction indicates that the recovery of rare earths from the slag using sub-molten salt medium is thermodynamically feasible.In this process,the rare earth fluoride and lithium in the slag are almost transformed into rare earth hydroxide,sodium fluoride and lithium hydroxide,fluorine and lithium are transferred into the washing solution,and the rare earths in the residues can be leached into solution by acid leaching.Under the optimum reaction conditions of reaction temperature 200℃,reaction time 3 h,NaOH initial concentration 80%,NaOH-Slag mass ratio 3:1,the leaching efficiency of rare earths,fluorine and lithium can reach to 99.05%,98.23% and 99.22%.After evaporation,the fluorine and lithium in the washing solution can be obtained in the forms of sodium fluoride and lithium fluoride,the recovery efficiency reach 95.5%and 92.8%,respectively.The RE oxides(99.53%) can be obtained from the leaching solution after precipitation and roasting.
基金Project(2013CB632605)supported by the National Basic Research Program of ChinaProjects(51274178,51090382)supported by theNational Natural Science Foundation of ChinaProject(KGCX2-EW-215)supported by the Key Deployment Program of ChineseAcademy of Sciences
文摘A series of innovative green metallurgical processes using novel reaction media including the NaOH/KOH sub-molten salt media and the NaOH-NaNO3 binary molten salt medium, for the extraction of vanadium and chromium from the vanadium slag have been developed. In comparison with the traditional sodium salt roasting technology, which operates at 850 ℃, the operation temperatures of these new processes drop to 200-400 ℃. Further, the extraction rates of vanadium and chromium utilizing the new approaches could reach 95% and 90%, respectively, significantly higher than those in the traditional roasting process, which are 75% and approximate zero, respectively. Besides, no hazardous gases and toxic tailings are discharged during the extraction process. Compared with the conventional roasting method, these new technologies show obvious advantages in terms of energy, environments, and the mineral resource utilization efficiency, providing an attractive alternative for the green technology upgrade of the vanadium production industries.
