钒页岩氧压酸浸过程中V与Fe的分离工艺研究

摘要

In order to explore the conditions of oxygen pressure acid leaching for a vanadium shale in Hubei,with K2SO4 as additive,the influence of K2SO4dosage,concentration of sulfuric acid,oxygen partial pressure,leaching temperature,and leaching time on leaching rate of vanadium and iron are investigated respectively during the extraction of Vanadium from black shale by oxygen pressure acid leaching.The results showed that under the conditions of K2SO4dosage 7%,the concentration of H2SO415%,leaching temperature 190 ℃ for 5h at 2.0mPa,the leaching rate of vanadium was 89.90% while the leaching rate of iron was only 5.73%.Obviously,the leaching rate of vanadium is increased,and the leaching rate of iron isgreatly re-duced compared with the tests without K2SO4.XRD phase and FTIR analysis showed that the addition of K2SO4intensified the crystal structure destruction ofmica which can promote the release of vanadium and increase its leaching rate.Yavapaiite sedi-ment (KFe(SO4)2) formed by the reaction of K+,SO2+4 and Fe3+reduces the leaching rate of iron,that is themain reason for separating vanadium and iron.Therefore,in the oxygen pressure acid leaching process of vanadium shale,the proper addition of K2SO4can increase the leaching rate of vanadium,and also effectively separate Vanadium and Iron,and reduce the negatively effects of Fe on the subsequent extraction process.%为了确定湖北某钒页岩氧压酸浸条件,以K2SO4为添加剂,对在氧压酸浸提V过程中K2SO4用量、硫酸的体积浓度、氧分压、浸出温度、浸出时间对V、Fe浸出率的影响进行了研究.结果表明,在K2SO4用量为7%、硫酸浓度为15%、浸出时间为5h、氧分压为2.0mPa、浸出温度为190℃条件下,V的浸出率为89.90%、Fe的浸出率仅为5.73%,较无K2SO4条件下V的浸出率提高,Fe的浸出率大幅降低.XRD、FTIR分析表明,K2SO4的介入能强化云母晶体结构的破坏,促进V的释放,提高了V浸出率;K+、SO2-4和Fe3+反应生成斜钾铁矾((KFe(SO4)2)沉淀,降低了Fe的浸出率,这是V与Fe有效分离的主要原因.因此,钒页岩氧压酸浸过程中适量添加K2SO4,不仅能提高V浸出率,而且能有效分离V与Fe,减少Fe对后续萃取工艺的不利影响.