A technological process for extracting vanadium from leaching solution of sodium roasting of vanadium slag by manganese salt pretreatment

Abstract

The ammonium salt precipitation method is frequently utilized for extracting vanadium from the leaching solution obtained through sodium roasting of vanadium slag. However, Na⁺ and NH₄⁺ ions in the vanadium precipitation solution can not be effectively separated, leading to a large amount of ammonia-nitrogen wastewater which is difficult to treat. In this study, the manganese salt pretreatment process is used to extract vanadium from a sodium roasting leaching solution, enabling the separation of vanadium and sodium. The vanadium extraction product of manganese salt is dissolved in acid to obtain vanadium-containing leaching solution, then vanadium is extracted by hydrolysis and vanadium precipitation, and V₂O₅ is obtained after impurity removal and calcination. The results show that the rate of vanadium extraction by manganese salt is 98.23%. The vanadium extraction product by manganese salt is Mn₂V₂O₇, and its sodium content is only 0.167%. Additionally, the acid solubility of vanadium extraction products by manganese salt is 99.52%, and the vanadium precipitation rate of manganese vanadate solution is 92.34%. After the removal of manganese and calcination process, the purity of V₂O₅ product reached 97.73%, with a mere 0.64% loss of vanadium. The Mn²⁺ and NH₄⁺ ions in the solution after vanadium precipitation are separated by precipitation method, which reduces the generation of ammonia-nitrogen wastewater. This is conducive to the green and sustainable development of the vanadium industry.