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.