Coextraction of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent extraction-precipitation process

High-manganese containing vanadium wastewater (HMVW) is commonly produced during the vanadium extraction process from vanadium titano-magnetite. HMVW cannot be reused and discharged directly, and is harmful to the environment and affect product quality due to heavy metals in the wastewater. The wastewater is usually treated by lime neutralization, but valuable metals (especially V and Mn) cannot be recovered. In this study, an efficient and environmentally friendly method was developed to recover valuable metals by using a solvent extraction-precipitation process. In the solvent extraction process, 98.15% of vanadium was recovered, and the V2O5 product, with a purity of 98.60%, was obtained under optimal conditions. For the precipitation process, 91.05% of manganese was recovered as MnCO3 which meets the III grade standard of HG/T 2836-2011. Thermodynamic simulation analysis indicated that MnCO3 was selectively precipitated at pH 6.5 while Mg and Ca could hardly be precipitated. The results of X-ray diffraction and scanning electron microscopy demonstrated that the obtained V2O5 and MnCO3 displayed a good degree of crystallinity. The treated wastewater can be returned for leaching, and resources (V and Mn) in the wastewater were utilized efficiently in an environmentally friendly way. Therefore, this study provides a novel method for the coextraction of V and Mn from HMVW.