Study On The Process Condition For The Pyrolusite Preparing Manganic-manganous Oxide By Wet Restoring

Using low grade pyrolusite as the raw material, with scrap iron and sawdust asreducing agents, the leaching solution was obtained by sulfuric acid leaching. Hydrogenoxidation manganese was precipitated out after adding the precipitating agent,that isammonia water.Then,making use of precipitated hydrogen oxidation manganese as theraw material,with air, hydrogen peroxide solution and ammonium persulfate asoxidizing agents, manganous-manganic oxide was prepared.Using low grade pyrolusite as the raw material, scrap iron, sawdust as reducingagents, the leaching solution was obtained by sulfuric acid leaching.When using scrapiron as the reducing agent,five factors on the influence of leaching rate of manganese inthe soft manganese were investigated,including iron-ore ratio, acid-ore ratio, liquid-solid ratio, reaction time and reaction temperature.Through four factors and three levelsof orthogonal experiments, influences of four factors on leaching rate of manganese inthe pyrolusite were compared. Four factors included iron-ore ratio, acid-ore ratio,liquid-solid ratio and reaction time. Results showed that, the leaching rate of manganesewas98%under the condition,which was,ratio of iron and ore was0.25:1,ratio of acidand ore was1:1,ration of liquid an solid was5:1，leaching temperatue was10℃andleaching time was1h.Near the condition, impact of four factors on leaching rate ofmanganese in descending order was: acid ore ratio was the best,leaching time was betterthan iron ore ratio,and liquid and solid ratio stayed the last place.When using sawdust as the reducing agent, five factors on the influence of leachingrate of manganese in the soft manganese were investigated, including sawdust-oreratio,acidity, liquid-solid ratio, reaction time and reaction temperature. Through fourfactors and three levels of orthogonal experiments, influences of four factors onleaching rate of manganese in the pyrolusite were compared. Four factors includedsawdust-ore ratio, acidity, reaction time and reaction temperature. Results showed that,the leaching rate of manganese was94%under the condition,which was,sawdust oreratio was0.3:1,acidity was30%,liquid and solid ratio was4:1,leaching temperatue was90℃,and leaching time was4h.Near the condition, impact of four factors on leachingrate of manganese in descending order was: sawdust ore ratio was superior toacidity,then was leanching temperatue, leaching time took the minimum impact.Leaching solution was purified by getting rid of iron, heavy metal,calcium,magnesium and silicon. Using cleaning leaching solution as the raw material,ammonia water as the precipitation agent,influences of temperature and pH on theprecipitation rate of hydroxide manganese were studied. Results showed that, the bestcondition was: when pH of the system was10and temperatue got40℃, the subsidenceratio of manganese reached83.7%.With hydrogen manganese oxide as the raw material, using air, hydrogen peroxidesolution and ammonium persulfate as oxidizing agents, nanoscale products ofmanganous-manganic oxide was prepared in the system of the solution.Severalparameters of the products,such as purity, crystal shape structure, particle size and soon, were characterized by flame atomic absorption, X-ray diffraction and scanningelectron microscope.Besides,the total recovery of manganese was determined.Resultsshowed that,when the manganous-manganic oxide was prepared by the leachingsolution,which was reduced by scrap iron,its content reached98%,and the content of manganese was71%as well.Compared with sawdust,the content of manganous-manganic oxide was97%,and the content of manganese was70%.Of course,theprodcuts of manganous-manganic oxide had some common points:the structure wascubic crystal structure,the particle size almost was100nm,and the total recover ofmanganese reached80%.The results provided some references for the exploitation of low grade pyrolusite.