Vanadium Leaching from Vanadium-Bearing Carbonaceous Shale by a Multi-stage Counter-Current Process

摘要

This study investigated vanadium leaching from carbonaceous shale by a multi-stage counter-current (MSCC) acid leaching process. Experimental results showed that MSCC leaching can decrease the consumption of acid and enhance the leaching rate of vanadium remarkably compared with the conventional leaching way. The leaching rate of vanadium can reach 86% under optimal conditions. When the leaching stage exceeded 3, two types of precipitation formed in the leaching solution after the solution cooled to below 40°C. One was suspended amorphous silica and the other was potassium alum crystals. The formation of amorphous silica can result in the loss of vanadium by electrostatic adsorption of VO~(2+) to the surface of the silica and the loss of aluminium was mainly due to the formation of potassium alum crystals. Hence, it was appropriate to decide on the three leaching stages for counter-current acid leaching in this study.