Address to the concentration of silicon in the alkaline leaching solution of high chromium vanadium slag after leaching by submolten salt method is too high(4-8 g/L),and the presence of silicon will have a great impact on the subsequent separation of vanadium and chromium,an experimental study was conducted on the removal of silicon from the oxygen-rich alkaline leaching solution of vanadium slag produced by an enterprise in Hebei Province.The effects of the type of precipitating agent,dosage of precipitating agent,alkalinity of leaching solution,reaction time,precipitation temperature and standing time on the removal of silicon and the loss of vanadium and chromium were investigated.The results show that the removal rate of silicon in alkaline leaching solution is 93.33%,the concentration of silicon reduces to 0.29 g/L and the loss of vanadium and chromium is less than 1%under the conditions including using NaAlO2 as a desilicide,mole ratio of n(Al)/n(Si)=1.8,concentration of hydroxylion(OH-)in leaching solution of 7.5 mol/L,reaction temperature of 85℃,reaction time of one hour,and the standing time of two hours.This method has good effect of removing silicon,short time and less loss of vanadium and chromium.The leaching solution after removing silicon meets the requirements of subsequent extraction of vanadium and chromium.
solution containing vanadium and chromiumdesilicationalkali leaching solutionchemical precipitation
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