Removal of manganous dithionate (MnS(2)O(6)) with MnO(2) from the desulfurization manganese slurry

Manganese desulfurization has been increasingly explored, but the generated manganous dithionate (MD) by-product affects the valuable use of the desulfurized slurry. In this study, α-MnO(2), β-MnO(2), γ-MnO(2), and δ-MnO(2) were prepared for MD removal in desulfurization manganese slurry. Results showed that δ-MnO(2) had the best activity among the four because of its porosity and favorable surface properties. The operation conditions showed that 12.00 g L(−1) MD can be removed by more than 80.00% under the conditions of 1.4 mol L(−1) sulfuric acid, 100 g L(−1) δ-MnO(2) dosage, and reaction at 90 °C for 3 h. The MD removal with MnO(2) followed the decomposition–oxidation pass and direct oxidation–reduction reaction and consequently induced structure destruction and crystalline transfer. MD removal with natural MnO(2) ore was also examined, and natural MnO(2) ore in the δ type was found to have prominent activity. Thus, this type of natural MnO(2) may serve as a good alternative to pure MnO(2) for decreasing the cost of MD removal from desulfurization manganese slurry.