Impact of Impurity Ions on Vanadium Precipitation Process of Stripping Solution from Vanadium Extraction of Stone Coal
Fu Zhaoyang Zhang Yimin Liu Tao Huang Jing Yang Xiaokang
College of Resource and Environment Engineering,Wuhan University of Science and Technology
Hubei Province Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource
Abstract:
Simulated stripping solution of one-step vanadium extraction from stone coal with V_2O_5 concentration of 17. 85 g·L~(-1),was used as the object of the study. Based on the production purity,the existing status of impurity ions in production and the condition of APV crystal structure,when different ions existed of the impact of impurity ions in simulated stripping solution such as Fe~(3 +),Al~(3 +),Ca~(2+),K~+on precipitation of vanadium by acidic ammonium was discussed. The result showed that with the existence of Fe~(3 +),Al~(3 +),the smooth process of the vanadium precipitation with acidic ammonium salt was influenced,and also the purity of the V_2O_5 was reduced. Meanwhile,the p H of mother liquor was changed by the existence of Fe~(3 +),Al~(3 +),which meant that the difficulty and cost of disposing of mother liquor would be increased. It also showed that only the purity of the V_2O_5 was influenced by the existence of Ca~(2+),K~+,the precipitation rate and the p H of mother liquor were not changed remarkably. And the crystal morphology of APV was altered for the presence of Al~(3 +),Ca~(2+),K~+,Fe~(3 +)though the principles of them were different. The crystal was destroyed and the size of crystal became smaller when Fe~(3 +)existed. And the integrity of crystal was destroyed by K~+. The effect of Ca~(2+)in the aspect of crystal embodied in two sides: the surface of crystal was harshened and there were adhesions between crystals,followed by the growth of crystal particles. The growth of crystal of ammonium polyvanadate was impeded by Al~(3 +)which became amorphous heteropoly acid. Meanwhile,to get good vanadium precipitation effect,the four ions concentrations were optimized as Fe~(3 +)<0. 1 g·L~(-1),Ca~(2+)<0. 9 g·L~(-1),K~+<2. 0 g·L~(-1),Al~(3 +)<3. 0 g·L~(-1).
图1 不同Fe3+离子浓度对沉钒率、V2O5产品纯度、沉钒母液p H的影响Fig.1Impact of different Fe3+concentrations on vanadium precipitation rate,V2O5product purity and p H of mother liquor
图2 添加Fe3+(7 g·L-1),Ca3+(1.06 g·L-1),K+(10 g·L-1),Al3+(10 g·L-1)与无杂质添加的模拟液得到的APV晶体对比Fig.2 Comparison of normal APV crystal(a)and APV crystal with(b)Fe3+(7 g·L-1),(c)Ca2+(1.06 g·L-1),(d)K+(10 g·L-1),(e)Al3+(10 g·L-1)
图3 Fe3+离子浓度为7 g·L-1的富钒液沉钒所得APV产品XRD分析Fig.3 XRD pattern of APV from vanadium precipitation by va-nadium-rich liquid with 7 g·L-1Fe3+
图4 不同Ca2+离子浓度对沉钒率、V2O5产品纯度、沉钒母液p H的影响Fig.4Impact of different Ca2+concentrations on vanadium precipitation rate,V2O5product purity and p H of mother liquor
图5 Ca2+离子浓度为1.06 g·L-1L的富钒液沉钒所得APV产品XRD分析Fig.5 XRD pattern of APV from vanadium precipitation by va-nadium-rich liquid with 1.06 g·L-1Ca2+
图6 不同K+离子浓度对沉钒率、V2O5产品纯度、沉钒母液p H的影响Fig.6 Impact of different K+concentrations on vanadium pre-cipitation rate,V2O5product purity and p H of mother liquor
表3 不同离子的多钒酸盐稳定常数Table 3 Stability constants of different multi-vanadate ions 下载原图
表3 不同离子的多钒酸盐稳定常数Table 3 Stability constants of different multi-vanadate ions
图8 不同Al3+离子浓度对沉钒率、V2O5产品纯度、沉钒母液p H的影响Fig.8Impact of different Al3+concentrations on vanadium precipitation rate,V2O5product purity and p H o mother liquor