| Summary: | In the process of preparing high-purity MnSO<sub>4</sub> from industrial MnSO<sub>4</sub> solution, it is difficult to remove Ca<sup>2+</sup> and Mg<sup>2+</sup> due to their closely similar properties. In this study, thermodynamic software simulation and experimental procedures were combined to remove Ca<sup>2+</sup> and Mg<sup>2+</sup> from industrial MnSO<sub>4</sub> solution to obtain high-purity MnSO<sub>4</sub>. The simulation model was applied to predict the trend of the crystallization of different ions in the solution upon the addition of H<sub>2</sub>SO<sub>4</sub>, which revealed that, at a volume ratio of H<sub>2</sub>SO<sub>4</sub> to MnSO<sub>4</sub> solution of more than 0.2, MnSO<sub>4</sub> started to crystallize and precipitate. The experimental results further verified the simulation results, and the yield of MnSO<sub>4</sub> increased with the increasing ratio of H<sub>2</sub>SO<sub>4</sub>, while the removal rate of Ca<sup>2+</sup> and Mg<sup>2+</sup> decreased gradually. Keeping the economic aspect in mind, the 0.3 ratio of H<sub>2</sub>SO<sub>4</sub> was selected at which the yield of MnSO<sub>4</sub> reached 86.44%. The removal rate of Ca<sup>2+</sup> and Mg<sup>2+</sup> by recrystallization reached 99.68% and 99.17% respectively after six consecutive cycles. The recrystallized sample was washed twice with anhydrous ethanol (volume ratio of ethanol to MnSO<sub>4</sub> solution of 0.5) and dried for 6 h at 120 °C, and the purity of MnSO<sub>4</sub>·H<sub>2</sub>O reached the battery grade requirements with the final yield as high as 80.54%. This study provides important guideline information for the purification of MnSO<sub>4</sub>·H<sub>2</sub>O from industrial MnSO<sub>4</sub> solution via a cost-effective, simple and facile approach.
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