Abstract:The manganese sulfate leachate obtained by wet leaching of manganese ore or manganese residue contains impurity ions of calcium and magnesium, which greatly affects the purity of subsequent manganese products. In order to deeply remove Ca2+ and Mg2+ in the manganese sulfate leachate, and maximize the utilization of manganese leachate, the purified manganese leachate can be prepared into high value-added MnO2 nanomaterials. The purified manganese leachate was prepared into high value-added MnO2 nanomaterials by hydrothermal method using (NH4)2S2O8 as oxidant after removing calcium and magnesium from manganese sulfate leaching solution containing calcium and magnesium. The effects of pH value of solution, reaction temperature, and reaction time on phase and morphology of the prepared MnO2 nanorods were investigated. The results show that the crystallinity of β-MnO2 is the best when the reaction temperature is 150 ℃, the reaction time is 10 h, the amount of oxidant added is the theoretical amount, and the reaction pH value is 1—7.