Temperature Control of Acid Leaching Process for Calcified Clinker of Vanadium Slag

The calcified clinker of vanadium slag is usually leached by sulfuric acid to obtain V-containing solution. During the industrial process of acid leaching, the leaching temperature increases abnormally and vanadium in the solution will be precipitated to decrease the recovery rate. In this paper, the effects of sulfuric acid concentration, sulfuric acid addition, solid-liquid ratio and the initial temperature of leaching agent on the leaching process were investigated. The results show that the sulfuric acid concentration, solid-liquid ratio and initial temperature of leaching agent influence the leaching temperature obviously. The leaching slurry temperature can be controlled to satisfy the process requirements with a higher vanadium leaching rate, at optimum conditions for leaching pH of 2.7～2.9,concentration of sulfuric acid ≤38%,solid-liquid ratio of 0.3～0.4 and leaching agent initial temperature of 25～35 ℃. Verified by industrial leaching production, the leaching temperature can be reduced by an average of 13.09 ℃,with the leaching rate of vanadium increasing by 3.45 percentage points.