First the manganese dioxide must be thoroughly washed and filtered to remove all soluble contaminants like zinc chloride and ammonium chloride.
In the first method 30grams of oxalic acid, 300mL of water, and 13mL of sulfuric acid are mixed together. Then the manganese dioxide is continually added until the solution stops bubbling.
In the second method. The manganese dioxide is mixed with water and an excess of sulfur dioxide is bubbled through. The reaction produces manganese dioxide directly.
Finally, after both methods. The mixture is filtered to give pink manganese sulfate.