Reductive leaching of manganese from low-grade manganese dioxide ores using corncob as reductant in sulfuric acid solution

Extraction of manganese from manganese dioxide ores was investigated using corncob as a reducing agent in dilute sulfuric acid medium. The effects of corncob amount, concentration of sulfuric acid, leaching temperature, reaction time and ore particle size were discussed. The leaching efficiency of manganese reached 92.8% while iron dissolved was 24.6% under the optimal condition which was determined for 10 g of manganese dioxide ore as corncob amount of 3 g, ore size of 75 μm, sulfuric acid concentration of 1.9 mol/L, leaching temperature of 85 °C for 60 min. In a word, the method provided a good leaching yield while making a productive use of corncob.