How is pure electrolytic manganese produced?

To produce pure electrolytic manganese, manganese ores are first roasted to create an MnO calcine, which is then dissolved in sulfuric acid to produce a manganous sulfate solution.1

The purification process involves:
* Precipitation: Ammonia is added to remove iron and aluminum, while hydrogen sulfide is used to precipitate other impurities, including arsenic, copper, zinc, lead, cobalt, and molybdenum.1
* Electrolysis: The purified solution is fed into the cathode portion of an electrolytic cell. When an electric current is applied, manganese is deposited onto a stainless-steel cathode sheet.1
* Finishing: The resulting manganese layers are removed from the cathodes by hammering. These flakes are then heated to 500 °C (925 °F) to eliminate hydrogen, yielding a final product with a purity greater than 99.9 percent.1