Abstract: The acid leaching filtrate of tailings from Jinchuan Company contains not only large amount of Fe²⁺ and Mg²⁺，but also small amount of Mn²⁺ impurity.The reactive activity of MnSO₄ with NaClO was thermodynamically calculated and analyzed. Moreover，with NaClO as oxidant and MgO as neutralizer，the optimum technological conditions of removal of manganese from the acid leaching filtrate were obtained by orthogonal experiments.Under the optimum conditions manganese was removed.Subsequently，Ca was further eliminated through heat filtration and MgSO₄·7H₂O was prepared by cooling and crystallizing the filtrate.Purity of the as-prepared MgSO₄·7H₂O was 98.4%（mass fraction），which can be classified as the first-rate product of type I according to the standard of HG/T 2680—2009.

Key words: acid leaching filtrate of tailings；removal of manganese；oxidizer；MgSO₄·, 7H₂O