The Leaching Of Manganese From Electrolytic Manganese Residueocess

Manganese is the key basic material of metallurgy, aerospace, chemical and the other industrial sector. However, the electrolytic metal manganese industry is facing enormous resources and environmental pressures with the rapid development, especially the harmless treatment of electrolytic manganese residue(EMR) and its resource ultilization are crucial issues. Some manganese still exists in manganese residue. The recovery of manganese not only reduces environmental pollution, but also creates huge economic benefit.The physicochemical properties of manganese residue change significantly after long-term storage in landfill. Traditional methods are inefficient in leaching manganese from landfilled manganese residue. Thus, electric field and chemicals have been used to intensify the leaching process of landfilled manganese residue.In the process of electroleaching, the experimental conditions were discussed and optimized. The optimum leaching conditions of manganese residue are liquid–solid ratio of 5:1 ml/g, 1.0%(v/v) sulfuric acid concentration, current density of 250A/m2, 25 ℃ and 1 h time. Under these optimal conditions, the leaching efficiency of manganese can reach 89.15%. The increase of the leaching rate was not obvious, with the increase of the liquid–solid, current density, sulfuric acid concentration and leaching time.The research of manganese recovery was explored after the electroleaching process. Firstly, The removal of iron was taken to get pure manganese products. And Certain amount of pyrolusite was added to leaching solution at proper agitation speed. The temperature was kept 50℃ for an hour with aeration of air. Certain amount of carbon powder was added with the p H value at 6. The method of carbide precipitation was used. The results shown that 97.77% of manganese was recycled. the concentration of manganese reached 43.47%. The product was mainly composed of Mn3O4, Mn O2 and Mn CO3.The EMR gradually condensed into solid lump and the low-price manganese were oxidated Mn O2 in long-term storage in landfill.Electric field can intensify the leaching of manganese residue. Mn O2 is reduced by production of cathodes, such as H· and iron ions. Various particles of manganese residue also closely aggregate together. Thus, electric field was used to influence the surface potential of these particles and allowed them to collide with each other to disperse Mn O2.In the process of chemicals leaching, the effect of oxalic acid and hydrazine hydrate were obvious. The optimum condition of oxalic acid leaching was the quality ratio of oxalic acid 4%, liquid–solid ratio of 5:1 ml/g, 1.0%(v/v) sulfuric acid concentration, 25℃ and 1h time. The optimum condition of hydrazine hydrate leaching was 0.5%(v/v) hydrazine hydrate concentration, liquid–solid ratio of 4:1 ml/g, 1.0%(v/v) sulfuric acid concentration, 25℃ and 1h time.