Deep Purification Of Industrial Leaching Liquid Of Manganese Sulfate And Manganese Tetroxide Preparation By Wet Chemical Method

Manganese tetroxide is a kind of structural materials of high performance, but also animportant raw material for the production of ferrite. At present, manganese tetroxide isprepared by electrolyzing manganese metal in our country.But, the cost of this method is highbecause of the price of manganese and the poor of its profitability. The inexpensivemanganese sulfate as raw materials, hydrolysis under alkaline conditions, air as the oxidant toprepared manganese tetroxide is a key development direction in the future. The purpose ofthis study is research and develop new methods and processes to remove calcium andmagnesium impurities, and preparation of qualified manganese tetroxide products from leanpyrolusite leachate.The impurity removal in manganese sulfate leaching solution of pyrolusie was discussedin this study. Based on the removal of iron and aluminum, as well as heavy metal ions, tofinding a new way to remove calcium and magnesium ions, to obtain pure manganese sulfatesolution. The results reads as follows: using30%P204added70%sulfonated kerosene asextraction solvent, saponification rate60%, temperature25℃, phase ration(O/A)3:1, keepingpH of solution about6.0at the beginning, the extraction yield of the calcium and magnesiumions is99.37%and90.62%respectively. Calcium and magnesium ions content can bereduced to less than100ppm, high purity manganese sulfate solution removed calcium andmagnesium ions deeply was obtained. The loaded organic phase via4.0mol/L sulfuric acidstripping, metal ions were stripped completely. The economically feasible process of usingthe leaching purification liquid and stripping liquid to preparation of high purity manganesecompounds was designed, and the whole process of integrated application of manganesesulfate leaching solution was achieved.Manganese sulfate, ammonia as raw materials, the air as the oxidant, using a two-step toprepared of manganese tetroxide. The manganese sulfate concentration, reaction temperature,pH value of the reaction system, ammonia concentration that affected the content of the sulfurof the hydrolyzate were discussed through single factor experiments. The optimum conditions:manganese sulfate concentration is0.65mol/L, the reaction temperature is60℃, theammonia concentration is10%, the final pH is10.The reaction temperature, pH value of thereaction system, the reaction time and the amount of ethanol additive that affected the contentof the manganese of the manganese tetroxide were discussed through single factorexperiments. The optimum conditions:temperature60℃, the pH value is maintained at9.5, reaction time8h, added ethanol20ml.The depth studies on basic manganese sulfate, which was the key intermediates,thataffected the purity of manganese tetroxide. Basic manganese sulfate were prepared by thehydrothermal reaction,the thermal decomposition behavior of basic manganese sulfate wasstudied by TG-DTA. The results show that, The thermal decomposition process ofMn2(OH)2SO4is divided into two stages. Integral equation G(ɑ)=[-ln(1-ɑ)]3/2can be used todescribe dehydration kinetics of basic manganese sulfate between200℃and400℃.Theaverage activation energy of the dehydration is calculated to be155.98KJ·mol-1.Mn2(OH)2SO4is decomposed while the temperature is between700℃and900℃. Thedecomposition kinetics can be described as integral equation G(ɑ)=1-(1-ɑ)1/4and its averageactivation energy is174.80KJ·mol-1．...