Roasting and leaching behaviors of vanadium and chromium in calcification roasting–acid leaching of high-chromium vanadium slag
来源期刊：International Journal of Minerals Metallurgy and Materials2018年第5期
论文作者：Jing Wen Tao Jiang Mi Zhou Hui-yang Gao Jia-yi Liu Xiang-xin Xue
文章页码：515 - 526
摘 要：Calcification roasting–acid leaching of high-chromium vanadium slag（HCVS）was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium.The effects of the purity of Ca O,molar ratio between Ca O and V2O5（n（Ca O）/n（V2O5））,roasting temperature,holding time,and the heating rate used in the oxidation–calcification processes were investigated.The roasting process and mechanism were analyzed by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and thermogravimetry–differential scanning calorimetry（TG–DSC）.The results show that most of vanadium reacted with Ca O to generate calcium vanadates and transferred into the leaching liquid,whereas almost all of the chromium remained in the leaching residue in the form of(Fe0.6Cr0.4)2O3.Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with Ca O.Moreover,Ca O was more likely to combine with vanadium,as further confirmed by thermodynamic analysis.When the HCVS with Ca O added in an n（Ca O）/n（V2O5）ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min,the leaching ratios of vanadium and chromium reached91.14%and 0.49%,respectively;thus,efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium.Furthermore,the oxidation and calcification reactions of the spinel phases occurred at 592and 630°C for n（Ca O）/n（V2O5）ratios of 0.5 and 5,respectively.
Jing Wen1，Tao Jiang1,2，Mi Zhou1,2，Hui-yang Gao1，Jia-yi Liu1，Xiang-xin Xue1,2
1. School of Metallurgy,Northeastern University2. Liaoning Key Laboratory for Recycling Science of Metallurgical Resources
摘 要：Calcification roasting–acid leaching of high-chromium vanadium slag（HCVS）was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium.The effects of the purity of Ca O,molar ratio between Ca O and V2O5（n（Ca O）/n（V2O5））,roasting temperature,holding time,and the heating rate used in the oxidation–calcification processes were investigated.The roasting process and mechanism were analyzed by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and thermogravimetry–differential scanning calorimetry（TG–DSC）.The results show that most of vanadium reacted with Ca O to generate calcium vanadates and transferred into the leaching liquid,whereas almost all of the chromium remained in the leaching residue in the form of(Fe0.6Cr0.4)2O3.Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with Ca O.Moreover,Ca O was more likely to combine with vanadium,as further confirmed by thermodynamic analysis.When the HCVS with Ca O added in an n（Ca O）/n（V2O5）ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min,the leaching ratios of vanadium and chromium reached91.14%and 0.49%,respectively;thus,efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium.Furthermore,the oxidation and calcification reactions of the spinel phases occurred at 592and 630°C for n（Ca O）/n（V2O5）ratios of 0.5 and 5,respectively.
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