A novel process of composite roasting with CaO/MgO and subsequent acid leaching was proposed to improve the recovery rate of vanadium from Linz–Donawiz(LD)converter vanadium slag.The effects of the MgO/(CaO+MgO)molar...A novel process of composite roasting with CaO/MgO and subsequent acid leaching was proposed to improve the recovery rate of vanadium from Linz–Donawiz(LD)converter vanadium slag.The effects of the MgO/(CaO+MgO)molar ratio and the roasting and leaching parameters on the recovery of vanadium were studied.The results showed that the leaching efficiency of vanadium decreased from 88%to 81%when CaO was replaced completely by MgO;however,it could be improved by roasting with the composite of CaO/MgO.The maximum vanadium leaching efficiency of 94%was achieved under the optimum MgO/(CaO+MgO)mole ratio of 0.5:1.The results from X-ray diffractometry(XRD)and scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM−EDS)confirm that the formation rate of acid-soluble vanadates can be enhanced during roasting with the composite of CaO/MgO and that the leaching kinetics can be accelerated owing to the suppression of calcium sulfate precipitation.展开更多
The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal an...The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the samples.The extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray patterns.The results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole ratio.The transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole ratio.The kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction model.The activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.展开更多
As an important strategic metal,vanadium is generally used to prepare special steels,titanium alloys,and hydrogen storage materials.A new method of producing vanadium(metal)powder from V_(2)O_(3)using block Mg is pres...As an important strategic metal,vanadium is generally used to prepare special steels,titanium alloys,and hydrogen storage materials.A new method of producing vanadium(metal)powder from V_(2)O_(3)using block Mg is presented herein.Using an auxiliary molten salt,V_(2)O_(3)was successfully transformed into V by Mg reduction.The by-product,MgO,was transformed into MgCl_(2)by adding ZrCl_(4),which prevented the generation of MgV_(2)O_(4)and allowed the reaction to proceed smoothly.The rod-like alloy phases,Zr_(0.03)V_(1.97),which formed in the presence of excess Mg,may hinder the diffusion of oxygen from the product.The recovery rate of vanadium after separation and purification was approximately 45%–50%,where the main loss occurred during ball milling.Under the optimal conditions(Mg content of 48.3%,reduction time of 1.5 h,and temperature of 850℃),the purity of vanadium exceeded 99 wt.%,and the O content decreased to 0.34 wt.%.展开更多
The chromium-bearing titanomagnetite ore will turn to be the important raw material for blast furnace process in Panxi area,China.The reduction behavior of Cr2O3 between CaO-SiO2-Al2O3-TiO2-Cr2O3 and Fe-C systems was ...The chromium-bearing titanomagnetite ore will turn to be the important raw material for blast furnace process in Panxi area,China.The reduction behavior of Cr2O3 between CaO-SiO2-Al2O3-TiO2-Cr2O3 and Fe-C systems was investigated.The effect of TiO2 content in the slag system on the reduction of Cr2O3,TiO2,and SiO2 and the con sumption of C in hot metal was investigated by both theoretical calculation and physical experiment.The theoretical calculation results reveal that higher reduction temperature promotes the reduction of Cr and Ti,while high basicity and TiO2 content have little influence on the reduction of chromium but significantly influence the reduction of Ti.The smelting reduction experiment results show that the content of Cr in hot metal significantly in creases with extendi ng the reduction time and decreases with the increase in TiO2 content.However,the content of Ti in hot metal significantly increases as the TiO2 increases,reaching 0.073,0.085,0.107,and 0.121 wt.%for 5,10,15,and 20 wt.%of TiO2 input,respectively.Kinetic studies proved that the reduction of Cr2O3 was a first-order reaction.The addition of TiO2 inhibited the reduction of Cr2O3 and resulted in the decrease in reaction rate constant.展开更多
基金supported by the National Natural Science Foundation of China (No.52004044)the Natural Science Foundation of Chongqing,China (No.CSTB2022NSCQ-MSX0801)+3 种基金the Foundation of Chongqing University of Science and Technology,China (No.ckrc2022030)the Graduate Research Innovation Project of Chongqing University of Science and Technology,China (No.YKJCX2220214)the Science and Technology Innovation Training Program of Chongqing University of Science and Technology,China (No.2022046)the College Students’Innovation and Entrepreneurship Training Program of Chongqing University of Science and Technology,China (No.2022007).
基金Project(2018M640898)supported by the China Postdoctoral Science FoundationProject(cstc2019jcyj-bshX0068)supported by the Natural Science Foundation of Chongqing,China+1 种基金Project(52004044)supported by the National Natural Science Foundation of ChinaProject(2018YFC1900500)supported by the National Key Research and Development Program of China。
文摘A novel process of composite roasting with CaO/MgO and subsequent acid leaching was proposed to improve the recovery rate of vanadium from Linz–Donawiz(LD)converter vanadium slag.The effects of the MgO/(CaO+MgO)molar ratio and the roasting and leaching parameters on the recovery of vanadium were studied.The results showed that the leaching efficiency of vanadium decreased from 88%to 81%when CaO was replaced completely by MgO;however,it could be improved by roasting with the composite of CaO/MgO.The maximum vanadium leaching efficiency of 94%was achieved under the optimum MgO/(CaO+MgO)mole ratio of 0.5:1.The results from X-ray diffractometry(XRD)and scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM−EDS)confirm that the formation rate of acid-soluble vanadates can be enhanced during roasting with the composite of CaO/MgO and that the leaching kinetics can be accelerated owing to the suppression of calcium sulfate precipitation.
基金This work was financially supported by the National Natural Science Foundation of China(No.52004044)the Natural Science Foundation of Chongqing,China(No.cstc2019jcyj-bshX0068)Chongqing Postdoctoral Innovation Program(No.CQBX201904),and the Open Project Founded by the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization.
文摘The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the samples.The extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray patterns.The results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole ratio.The transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole ratio.The kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction model.The activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.
基金the National Key Research and Development Program of China(2018YFC1900500)Technology of Preparing High Purity Metal Vanadium Powder by Magnesium Reduction(2018CDPZH-16)the open project founded by State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization for financial support of this research.
文摘As an important strategic metal,vanadium is generally used to prepare special steels,titanium alloys,and hydrogen storage materials.A new method of producing vanadium(metal)powder from V_(2)O_(3)using block Mg is presented herein.Using an auxiliary molten salt,V_(2)O_(3)was successfully transformed into V by Mg reduction.The by-product,MgO,was transformed into MgCl_(2)by adding ZrCl_(4),which prevented the generation of MgV_(2)O_(4)and allowed the reaction to proceed smoothly.The rod-like alloy phases,Zr_(0.03)V_(1.97),which formed in the presence of excess Mg,may hinder the diffusion of oxygen from the product.The recovery rate of vanadium after separation and purification was approximately 45%–50%,where the main loss occurred during ball milling.Under the optimal conditions(Mg content of 48.3%,reduction time of 1.5 h,and temperature of 850℃),the purity of vanadium exceeded 99 wt.%,and the O content decreased to 0.34 wt.%.
基金supported by the project funded by China Postdoctoral Science Foundation(Grant No.2018M640898)the National Key Research and Development Program of China(2018YFC1900500)+1 种基金the National Natural Science Foundation of China(No.51674055)the open project funded by State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization.
文摘The chromium-bearing titanomagnetite ore will turn to be the important raw material for blast furnace process in Panxi area,China.The reduction behavior of Cr2O3 between CaO-SiO2-Al2O3-TiO2-Cr2O3 and Fe-C systems was investigated.The effect of TiO2 content in the slag system on the reduction of Cr2O3,TiO2,and SiO2 and the con sumption of C in hot metal was investigated by both theoretical calculation and physical experiment.The theoretical calculation results reveal that higher reduction temperature promotes the reduction of Cr and Ti,while high basicity and TiO2 content have little influence on the reduction of chromium but significantly influence the reduction of Ti.The smelting reduction experiment results show that the content of Cr in hot metal significantly in creases with extendi ng the reduction time and decreases with the increase in TiO2 content.However,the content of Ti in hot metal significantly increases as the TiO2 increases,reaching 0.073,0.085,0.107,and 0.121 wt.%for 5,10,15,and 20 wt.%of TiO2 input,respectively.Kinetic studies proved that the reduction of Cr2O3 was a first-order reaction.The addition of TiO2 inhibited the reduction of Cr2O3 and resulted in the decrease in reaction rate constant.
