Preparation Of Manganese From Electrolytic Manganese Residue And Its Application In Treating Wastewater Containing Copper

The Mn forms in waste residue of electrolytic manganese metal (EMM) and its influence to the environment was analyzed. The forms of Mn in EMM waste residue are chiefly the dissociated Mn2+, carbonate, and MnO2. There are about 50% of total Mn is Mn2+ dissolved by water, and the best leaching concentrate is up to 3.7mg/ml which is much higher than that of nation's discharge standard. The pH of the leaching liquid is 5, and it means the waste residue is acidic. If the waste residue of EMM is discharged directly to land, it will cause serious pollution environment.When the waste residue of EMM was leached with sulfuric acid, the leaching conditions are obtained by the orthogonal experiment. Namely, the liquid-solid ratio of the reaction system is 3:1, the concentration of sulfuric acid is 20%, the leaching temperature is 90℃and the leaching time is 3h. The results were shown that the leaching ratio of manganese is up to 96%. Finally, 91% of MnSO4 could be obtained by the method of two steps depuration .By the method of single factor, the effect of roasting conditions on Mn leaching ratio for treating EMM residue with ammonium salt has been researched. When the mixture of the waste residue of EMM and(NH4)2SO4 (1:1) was roasted for 1h at 450℃, Mn leaching ratio is up to 83%. Finally, 98% purity of MnSO4 has been obtained through remove of impurity. The process, economic efficiency and enviornmental benefit on the above two methods have been compared. From considering only the process, the roasting with ammonium salt is more suitable method.Based on the analyze of different residue's components, the residue after roasting with ammonium salt method, which has bigger specific surface area, was chose to remove the copper ion in the wastewater. The results was shown that the residue has a better disposal efficiency for copper ion in 60mg/L of containing copper wastewatert. When the pH of the wastewater is 6, the mass residue is 1.5g and treating time is 2.5 hoursm, the removal ratio of Cu2+ was reached 96% at room temperature.