Process for producing solid manganese dioxide

A process for producing manganese dioxide comprising the steps of:

• (1) reacting manganese oxide with an aqueous chloric acid solution wherein the chloric acid is in molar excess to the manganese oxide in a reaction zone to form a reaction mixture in said zone consisting essentially of chlorine gas, a solid phase containing manganese dioxide, and a liquid phase containing chloric acid and water;
• the concentration of chloric acid in said liquid phase is greater than about 5% by weight of said liquid phase upon leaving the reaction zone;
• (2) separating said chlorine gas from said solid phase and said liquid phase;
• (3) separating said solid phase containing manganese dioxide from the liquid phase containing chloric acid and water thereby forming a separated solid phase and a separated liquid phase;
• (4) removing water from said separated liquid phase to concentrate said chloric acid in said separated liquid phase, thereby forming a separated and concentrated liquid phase;
• and
• (5) returning said separated and concentrated liquid phase back to said reaction zone for further reaction with manganese oxide.