Abstract: A method of producing manganese metal or EMD by leaching a source of manganese with a solution comprising sulfuric acid to form a leach solution, adding one or more sulfides generated in a sulfide recycle stage to the leach solution in order to form sulfide precipitates comprising heavy metal sulfides, removing the sulfide precipitates from the leach solution, feeding the leach solution to one or more electrolytic cells, subjecting the purified leach solution to electrolysis so as to deposit manganese metal or EMD, reacting the sulfide precipitates with an acid to generate H2S, producing one or more sulfides from the H2S for recycle. Methods of producing manganese metal and a purified manganese sulfate solution are also provided.

Abstract: A method of producing manganese metal or EMD by leaching a source of manganese with a solution comprising sulfuric acid to form a leach solution, adding one or more sulfides generated in a sulfide recycle stage to the leach solution in order to form sulfide precipitates comprising heavy metal sulfides, removing the sulfide precipitates from the leach solution, feeding the leach solution to one or more electrolytic cells, subjecting the purified leach solution to electrolysis so as to deposit manganese metal or EMD, reacting the sulfide precipitates with an acid to generate H2S, producing one or more sulfides from the H2S for recycle. Methods of producing manganese metal and a purified manganese sulfate solution are also provided.

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.