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.

Key words: Sodium roasting leaching solution of vanadium slag, Manganese salt pretreatment, Acid dissolution, Vanadium precipitation by hydrolysis, V₂O₅

摘要： 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.

关键词: Sodium roasting leaching solution of vanadium slag, Manganese salt pretreatment, Acid dissolution, Vanadium precipitation by hydrolysis, V₂O₅