Abstract: Using the electrolytic process to make manganese metal, a source of manganomanganic oxide (Mn.sub.3 O.sub.4) is used in the sulfuric acid leach solution in conjunction with a reducing agent to convert the manganomanganic oxide into manganese sulfate for treatment in the electrolytic cell. Sources of manganomanganic oxide include sintered manganese ore, manganese ore having less than 7% available oxygen such as Assoman Ore, and MOR fume. Reducing agents include sulfur dioxide, activated carbon, reducing sugars and molasses.

Abstract: The process calculates the amount of silica and oxidizing agent to use in a refining process for metallurgical-grade silicon. The calculation for silica takes into account (1) the aluminum content of the previous batch of refined silicon; (2) the calcium content of the previous batch of refined silicon; (3) the trend in the aluminum content of the unrefined silicon; and (4) the age of the ladle used for refining. The process then calculates the amount of silica based on a predetermined minimum amount of silica to add, a predetermined maximum amount of silica to add and the amount of silica added to the previous batch of refined silicon. The calculation for oxidizing agent is based on (1) the aluminum content of the previous batch of refilled silicon; (2) the calcium content of the previous batch of refined silicon; and (3) the age of the ladle.