Study Of Treating Manganese Oxide Ore By Reduction Acidolysis And Iron Removal Leaching

Manganese oxide ore is one of the major type of manganese resource,and the research and utilization of these ores make great sense to manganese industry in China.The key to treating manganese oxide ore is to select reducing agent.Biomass reductant as a renewable,carbon neutral reducing agent,which is characterized by low prices,large quantities,and environmentally friendly,is an ideal reducing agent.In this paper,the reduction acidolysis technology was developed to solve the problems of high acid,high temperature and long time in processing manganese oxide ore with biomass as reducing agent.Reduction acidolysis technology is to mix sawdust,manganese oxide and a small amount of water,and then concentrated sulfuric acid was added.Concentrated sulfuric acid was used to carbonize and hydrolyze sawdust,which can activate the sawdust and produce reducing carbon and organic compound.Meanwhile the heat generated by concentrated sulfuric acid dissolving in water provides the high-temperature environment and reaction driving force.Under the high temperature,the high valence of manganese was reduced,and manganese sulfate was produced.In addition,in view of the current status of the separation of leaching and iron removal in the treatment of manganese ore,the iron removal leaching technology is put forward in this paper.The technology of iron removal leaching can shorten the process and reduce the cost,and also suitable for other metallurgical process.To reduce the entrainment loss of manganese in the iron removal process,goethite process was adopted.The main controlling factors of goethite process were pH and c(Fe3+).Compared with the traditional goethite process,in this experiment,pH was adjusted by mixing the acidolysis material and the neutralizing agent.The c(Fe3+)in the solution is controlled by the way of slow feeding,and finally the leaching and iron removal can be achieved at the same time.The optimum conditions for reduction acidolysis were as follows:reducing agent/ore of 0.3,acid/ore of 1,water/ore of 0.8,aging time 12h,both the original reducing agent particle size and the ore particle size of over 74 ?m 99.46%.The optimum conditions for iron removal leaching were as follows:neutralizer/ore of 0.125,leaching temperature of 95?,leaching time of 2h and liquid/solid ratio of 6.The leaching efficiency of manganese was 94.15%and the purification efficiency of iron was 99.79%.In the solution,c(Mn2+)was 31.52g/L and c(Fe3+)was 0.0074g/L.In purification process,MnF2 was used to remove calcium and magnesium,MnS to remove heavy metals,and activated carbon to adsorb organics.The optimum conditions for the purification are as follows.(1)Removal of calcium and magnesium by MnF2:initial pH of 4.5,temperature of 85?,the theoretical amount of twice times the purifying agent,time of 80min;(2)Removal of heavy metals by MnS:initial pH of 5.5,temperature of 95?,the dosage of MnS of 4.0g,time of 120min;(3)Removal of organics by activated carbon:initial pH of 6.0,room temperature,the dosage of activated carbon 10g,time of 120min.The purification efficiency of Ca2+ and Mg2+ were 89.10%and 86.35%,respectively;c(Cu2+),c(Pb2+)and c(Cd2+)in the solution were all less than 0.00001 g/L;the purification efficiency of organics was 85.47%;and c(Mn2+)was 43.78g/L.