摘要
The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.
研究含铬钒酸盐溶液分离回收钒的循环冶金工艺,工艺过程包括溶液中钒的选择性沉淀、沉淀物中钒的浸出及五氧化二钒的制备。在含铬钒酸盐溶液中加入Ca(OH)_(2)进行球磨,不仅可以使其中的钒选择性沉淀析出,而且沉淀物的浸出动力学性能得到显著改善。在含铬钒酸盐溶液中按Ca/V摩尔比1.75:1加入Ca(OH)_(2),室温球磨60 min,钒的沉淀率达99.59%,而铬的沉淀率只有0.04%。过滤得到的沉钒渣按液固比4:1 mL/g加水,并按NaHCO_(3)/V摩尔比2.74:1加入NaHCO_(3),室温搅拌60 min,过滤得浸出液,钒的浸出率为99.35%。所得浸出液先通入CO2调pH至8.0,再按NH_(4)HCO_(3)/NaVO_(3)摩尔比1:1加入NH_(4)HCO_(3),室温搅拌8 h结晶析出NH_(4)VO_(3),过滤后,含氨的结晶液重新用于钒酸钙沉淀的浸出,温室搅拌1 h后钒的浸出率>99%,最后,将所得NH_(4)VO_(3)晶体在560℃煅烧2 h得到纯度为99.6%的V_(2)O_(5)。
基金
The authors are grateful for the financial supports from the National Natural Science Foundation of China(51974369)
the Postgraduate Research Innovation Project of Central South University,China(2019zzts244).
