There are two mainstream preparation processes for Mn3O4, namely the manganese metal oxidation method and the manganese sulphate oxidation method.

The manganese metal oxidation method uses electrolytic manganese metal as the raw material. It involves grinding to produce a manganese suspension, introducing air for oxidation under specific temperature and catalyst conditions, and finally obtaining the Mn3O4 product through filtration, washing, and drying processes.

The manganese sulphate oxidation method prepares Mn3O4 through a two-step oxidation process. First, sodium hydroxide is added to a high-purity manganese sulphate solution to neutralize and produce a precipitate. After multiple washings of the precipitate, oxygen is introduced for the oxidation reaction. Subsequently, the precipitate undergoes further washing, filtration, aging, slurry adjustment, and drying processes to obtain the Mn3O4 product.

Comparing the two processes, the manganese metal oxidation method offers more advantages for Mn3O4, mainly in terms of better stability, higher purity, superior impurity control, more controllable magnetic properties, and cost advantages. Therefore, this process is extremely important for the accelerated promotion and application of Mn3O4 in manganese-based cathode materials, especially in new-type manganese-based cathode materials.