Preparation method of battery-grade manganese sulfate

The invention discloses a preparation method of battery-grade manganese sulfate. The preparation method specifically comprises the following steps: 1) mixing manganese ore powder and adding sulfuric acid for leaching to obtain a manganese sulfate leaching solution; 2) adding an oxidant to the manganese sulfate leaching solution, then adding an alkaline substance to adjust pH to 5-6, and adding sulfide to remove heavy metals such as copper, zinc and lead to obtain a manganese sulfate initial solution; 3) adding an iron-containing agent to the manganese sulfate initial solution to remove potassium and sodium impurities in the manganese sulfate solution to obtain a manganese sulfate purified solution; 4) adjusting pH of the manganese sulfate purified solution to 0.5-3 with sulfuric acid, performing heating for concentration and partial crystallization to obtain a manganese sulfate crystal, slurrying the crystal with purified water, and adding a high-purity manganese raw material to adjustpH to 5-6, and performin