In manufacturing manganese metal, two different electrolytic processes are used to convert manganese in aqueous solution to metal. One 99.7% manganese product is produced by adding selenium dioxide to the electrolyte, which improves energy efficiency and therefore reduces power consumption and product cost.

The other 99.9% manganese product applies sulphur dioxide in solution, consuming more power but without potentially environmentally hazardous selenium and other residuals in the manganese metal product. Additionally, production of 99.9% manganese metal minimises waste disposal impacts due to the high-grade manganese ores used.

The advantages and disadvantages of the two approaches are discussed by Karen Hagelstein (aircaredoc@aol.com) in the September 2003 issue of Mining Environmental Management (pps. 12-13)