| Desilver waste liquid taken from a certain Ag-Mn mine in Guangxi Province, which contained Mn 69-73 g/L, H2SO4 92~125g/L, Fe 15-21 g/L and a little amoune of Co, Ni etc., was used as the raw materials for preparation electrolytic manganese dioxide (EMD), and a new process of preparation EMD, consisting of pre-oxidation, deferrization, elimination of heavy metals, electrilysis, post-treatment of EMD, and so on, was successfully developed by experiments.Main effects on preparing EMD were investigated in the experiment, and then the optimal conditions were found. In the procedure of deferrization by the rubinglimmer method, results of pre-oxidation esperiments indicated that at suitableconditions (the dosage of oxidant MnO2 1.08times in theory, oxidation reaction time 60 minutes and temperature 80),the oxidation rate of Fe2+ could reach 100%. In order to reduce impurities in solution MnCO3 mineral and CaO were used as neutralizing agents to adjust the solution pH (inal pH value 5-6), iron almost could be removed when neutralization reaction time was 180 minutes and temper 90C. The filter residue of iron, where the content of Mn was 9.75%, had been washedtwice: first washery was performed by recycle water in the second washing procedure (washing for 60 minutes at 60 C), in the second washery procedure lasted for 60minutes at 60 C by using pure water 1.5L and H2SO4 3mL, results of deferrization experiments showed that the Fe removing ratio, the Mn recovery ratio could reach 100% and 84.71% (with pyrolusite) or 86.68% (without pyrolusite) respectively. Based on theoretical analysis of the feasibility, the sulphuration-sediment method was introduced to remove heavy metals and S.D.D. was selected as the vulcanizing agent. It was shown that at suitable conditions (the dosage of S.D.D. 2g/L, temperature 60C, time 60 minutes), the removing ratio of Ni, Co, Zn could reach 99.8%, 95.96% and 41.94%, the percentage loss of Mn was around 7.30%. Afer purification procedure the original liquid coule meet the necessity of electrolysis, when technics conditions of electrolysis reaction were as following: the concentration of Mn2+, H2SO4 in the electrolyte 37~50f/L and32-41 g/L respectively, temperature 95 C, current density 40~50A/m2 , electrode distance 110~136 cm, cell votage 2.22v, anode current efficiency coule reach 96.2% and power consumed was 1421 kw ?h/t EMD, the balanced error of Mn was only -5.39%. At last EMD generated in the electrolysis procedure was washed and pH value adjustment in the post-treatment in the post-treatment procedure, main content of MnO2 and Fe of EMD, and the discharge performance of test sample battery could all measure up to standard of QB2106-95 A.The whole technics processes designed were stable and reliable, where most procedure was closed-circuit and less waste water and no pollutional gas were produced, the content of waste water and residue coule arrive at the effluent standard. At the end of the thesis, some designs about industrial production (1800t/a) of the newly developed process were made for the Ag-Mn Mine in Guangxi.
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