국산 rhodochrosite 로부터 제조한 황산산성 $MnSO_4$ 수용액을 전해산화하여 건전지용 ${gamma}-MnO_2$를 제조하는데에 관한 공업적 데이터를 얻기 위하여 하루에 4kg의 $MnO_2$를 제조할 수 있는 micro pilot plant를 설치하여 실험하였다. 광석의 침출 및 전해산화 조건을 규명하고 제품의 물성을 화학분석, DTA, X-선회절, 전자현미경사진 및 전지방전 실험 등으로 검토하였다. 적합한 전해조건은 다음과 같다. 전해액의 온도 : $90^{circ}C$ 이상, 전류밀도 : 0.7${sim}A/dm^2$, 양극재료 : 흑연 또는 납, 전해액의 농도 :$MnSO_4 50{sim}150g/l $및 $H_2SO_4/MnSO_4 = 0.15{sim}0.25$. 최적전해조건하에서 전류효율은 99%이었고 생성된 $MnO_2$는 거의 순수한${gamma}-MnO_2$이었으며, 방전특성은 우수하였다.
With the intention of obtaining technical data for the industrial production of ${gamma}-MnO_2$ for dry cell depolarizer by electrolytic oxidation of acidic manganese sulfate solution made from domestic rhodochrosite, optimum conditions of ore leaching, purification of leached solution and electrolytic oxidation of divalent manganes to tetravalent were investigated using simulated micro pilot plant having a production capacity of 4 kg of $MnSO_4$ per day. The nature and quality of the products were investigated by means of chemical analysis, DTA, X-ray diffraction and electron microscopy. The cell activity of $MnO_2$were examined by cell discharging character measurements. The optimum electrolysis conditions were as follow: Temperature of the electrolyte, above $90^{circ}C$; current density, 0.7${sim}A/dm^2$; anode materials, graphite or lead ; concentration of electrolyte, $MnSO_4 50{sim}150g/l $ g/l and $H_2SO_4/MnSO_4 = 0.15{sim}0.25$. Under the best condition the current efficiency was 99% and the products were almost pure ${gamma}-MnO_2$. The cell discharging character were good and almost the same as that of regular grade commercial electrolytic manganese dioxide.
