钙化-酸浸提钒沉钒母液中锰的回收

对钙化?酸浸提钒沉钒母液中锰资源的回收，一方面可以提升提钒工艺的经济效益，另一方面可避免母液循环时锰浓度不断累积而影响氧化钒产品质量，从而有助于实现母液闭路循环而提升全流程的环境效益。本工作提出了采用草酸沉淀法高效回收沉钒母液中的Mn2+，考察溶液体系pH值、草酸加量系数、反应温度和时间对锰回收率及沉淀产物物相组成的影响，以及草酸沉淀分离锰后母液的循环次数对钒浸出过程的影响。结果表明，草酸沉淀法可高效分离沉钒母液中的Mn2+，在溶液体系pH=4.0、草酸加量系数为1.5、反应温度为50℃、反应时间为60 min的条件下，锰回收率达94.33%，所得产物为纯度大于98%的水合草酸锰，为片状晶体，并呈花簇状生长。将脱锰后的沉钒母液循环至酸浸段，对钒浸出率及浸出液中锰的浓度没有明显影响，表明该方法有助于实现钙化?酸浸提钒中废水的闭路循环。

Recovery of manganese from the mother liquor after vanadium precipitation during vanadium extraction with calcified roasting and acid leaching process

Recovering manganese resource from the mother liquor on one hand can improve the economic benefit of the whole process, and on the other hand is beneficial to realizing closed cycle of mother liquor and then can increase the environmental interest of the whole process because it can avoid the enrichment of Mn in the solution during recycling mother liquor which will bring side effect to the quality of vanadium pentoxide. Using oxalic acid to effectively separate the Mn2+ from the mother liquor was proposed and the effects of the solution pH, adding amount coefficient of oxalic acid, reaction temperature and time on the recovery rate of Mn and phases composition of the precipitations were investigated, and the effect of the numbers of recycling mother liquor treated by oxalic acid to recover manganese on the leaching process was studied as well. The results showed that oxalic acid can effectively separate the manganese from the mother liquor and the recovery rate of manganese reached 94.33% under the conditions that the solution pH was 4.0, adding amount coefficient of oxalic acid was 1.5, reaction temperature was 50℃ and the reaction time lasted for 60 min. The obtained product was hydrated manganese oxalate with purity of 98%, present as tabular crystals and formed in flower cluster-like. After treated with oxalic acid to remove manganese, the mother liquor was recycled to leach the roasted slag, and it was found that the recycling numbers have little effect on the vanadium leaching rate and the concentration of manganese contained in the vanadium-bearing solution, indicating the proposed method was helpful for realization of closed-cycle of the waste water in the whole process of vanadium extraction with calcified roasting and acid leaching.