酸浸对钙化焙烧提钒工艺钒浸出率的影响

Effect of Acid Leaching on the Vanadium Leaching Rate in Process of Vanadium Extraction Using Calcium Roasting

采用稀硫酸浸出法提取钙化焙烧后钒渣中的钒,考察了浸出参数：物料粒度、体系pH值、浸出温度和时间、液固比（L/S）、搅拌速度对钒及杂质元素浸出率的影响.结果表明：物料粒度小于75μm时对提高钒浸出率影响较小;液固比从2∶1增加到7∶1,搅拌速度由100增加到500 r/min时,钒浸出率增长幅度均低于3%;钒浸出率在浸出前15 min内迅速升高,之后增长变缓;浸出体系pH值对钒及杂质浸出率影响显著,pH值为2~3时钒浸出率达90%,杂质元素Ca,Mn,Mg,Al,Si,P浸出率为10%~30%;在较佳浸出条件下：粒度96~75μm,pH值为2.5,温度55℃,时间30 min,L/S为3,搅拌速度500 r/min,钒浸出率超过91%.

Sulfuric acid leaching was used to recover vanadium from calcium roasting vanadium slag. The effects of particle size, pH, leaching temperature, time, ratio of liquid to solid （ L/S）, stirring speed on the leaching rate of vanadium and impurities were investigated. The results showed that the vanadium leaching rate increases slowly when the particle size is smaller than 75 p.m, and it is improved by less than 3% with increasing L/S from 2：1 to 7：1 and the stirring speed from 100 to 500 r/min. The pH value has great effect on vanadium recovery. The leaching rate of vanadium reaches over 90% , and the leaching rate of impurities, like Ca, Mn, Mg, A1, Si, P, are 10% -30% in pH range from 2 to 3. Under the optimal conditions of particle size of 96. 75 μm, pH of 2.5, temperature of 55 ℃,time of 30 min, L/S of 3 and stirring speed of 500 r/min, the vanadium leaching rate is over 91%.