Abstract: The mixture of sodium hydroxide and ammonia , sodium carbonate or sodium hydrogen carbonate are used as precipitants to treat the manganese-containing wastewater produced in the production of trimanganese tetroxide.The effect of the type and dosage of the precipitants, precipitation temperature, flocculant and aging time on the precipitation of manganese ions and the factors influencing the impurity content of trimanganese tetroxide are studied.The manganese ion content in the treated wastewater can be below 2×10^-6 and the manganese ions recovered can be used to prepare high pure trimanganese tetroxide.

Key words: Trimanganese tetroxide, Wastewater, Manganese ion