Thepreparationofchemicalmanganesedioxide(CMD)fromlow-graderhodochrositeore(LGRO)inXiushan,Chongqing,wasstudiedandimproved,includingleachingwithsulfuricacid,purifying,crystallizinganddecomposingofMnCO3,andrefiningofprimaryMnO2.TheproductwascharacterizedbyX-raydiffraction.Theresultsshowedthattheextractionratio,themanganeserecoveryratioofpurifying,crystallizationandrefiningreached96.8%,93.9%,97.7%and85.4%,respectively.Theoptimumconditionsofrefiningweredescribedasfollows:liquid(H2SO4)/solid(primaryMnO2)ratiowas3L/g,theconcentrationsofNaClOexceeded20%,andreactiontimewas3hours.Undertheaboveconditions,thecontentsofMnO2andMnintheobtainedmanganesedioxidewererespectively85.1%and53.9%.TherefinedMnO2canbeusedasthesupergrademanganesedioxideminepowderinchemicalindustry.TheXRDindicatedthatthestructureoftheproductwasγ-MnO2.
