| 摘要 |
PROBLEM TO BE SOLVED: To manufacture manganese dioxide for a dry battery having the predetermined grain size and capable of reducing the content of impurities by electrolyzing the manganese sulfate aqueous solution, peeling the manganese dioxide deposited in a positive electrode plate, and coarsely crushing it, and performing the wet-classifying to the fine crushed manganese dioxide slurry discharged after wet-crushing. SOLUTION: In the case of wet-crushing, slurry concentration at the time of crushing is adjusted at 30-90 wt.%, and the temperature thereof is held at 50-80 deg.C, and wet-classifying is performed while spraying an equivalent or more of the hot water on the manganese dioxide powder included in the slurry including the powder crushed for a predetermined crush time, and decantation is performed to the recovered slurry including the powder having the predetermined grain size only one time so as to eliminate the residual electrolyte and a sulfate radical. Such a strong agitation in the acid solution at pH3.5 or less effectively works to the dissolution for elimination of the heavy metal contaminated at the time of electrolytic deposition and thereafter till the slurry is put into a fine crushing device. |
