Reductive dissolution of manganese ore in sulfuric acid in the presence of iron metal

The dissolution of a manganese dioxide ore in dilute sulfuric acid facilitated by Fe metal in the form of powdered sponge iron was investigated. Effects of such parameters as molar ratios of sponge iron and sulfuric acid to manganese dioxide, temperature, particle size of sponge iron as well as ore particle size on the dissolution efficiency were studied. The results showed that manganese could be rapidly leached out to a complete degree even at room temperature. Based on both theoretical and experimental facts, it was concluded that the usage of metallic iron for the reductive leaching of manganese dioxide was superior to that of ferrous ion as far as dissolution rate and efficiency were concerned.