Investigation on Separation of Vanadium and Chromium in Alkaline Solution and Preparation of V₂O₅ and Cr₂O₃ Products

This paper focused on vanadium and chromium separation in solution using hydrolysis technology.The factors of p H value,temperature and time for vanadium precipitation have been investigated to study their effect on the precipitation rate of vanadium,and the optimum parameters have been determined as follows: p H of 2,temperature of 90 ℃ and time of 60 min,at which the precipitation ratio of vanadium exceeds 98% with less than 0.3% of chromium residual in the filtration cake after washing.Chromium mainly remains in solution through precipitation,which realizes simple and efficient separation of vanadium and chromium in solution.V₂O₅ products with purity more than 99% can be obtained stepwise via alkali dissolution of the vanadium cake,vanadium precipitation by（NH₄）₂SO₄ and calcination.Using Fe₂（SO₄）₃ to remove vanadium in chromium solution,Na₂SO₃ for reduction and Na OH for precipitation,pigment grade Cr₂O₃ can be acquired by roasting the washed Cr（OH）₃.This work has realized low cost and high efficiency separation of vanadium and chromium in solution as well as preparation of high quality vanadium and chromium products,with 97% and 86.4% of total yield rate for vanadium and chromium,respectively.