The Manufacture Of Lithium Manganese Iron Phosphate Precursor Using Low-grade Manganese Ore And Crap Iron

With the continuous exploitation and utilization,the reserves of high-grade manganese ore are diminishing.Since the mineral processing method can not improve its grade,a lot of low-grade manganese ore have not yet been used,Aiming at the problem that it is difficult to utilize low-grade manganese ore,in this paper,the preparation of the promisng lithium manganese iron phosphate precursor by low-grade manganese ore and crap iron was investigated,which provides a new way for processing low-grade manganese ore.The reductive leaching of manganese ore,purification of leaching solution and preparation of precursor with co-precipitation method were all studied.(1)A high purity lithium manganese iron phosphate precursor can be obtained by manganese ore leaching with crap iron as reductant,purification and ferromanganese co-precipitation.The price of crap iron and low-grade manganese ore is low,and the leaching process can be carried out at room temperature,without the process of ferromanganese separation and evaporation crystallization.Therefore,this technology has the advantages of simple and energy saving.(2)The optimal conditions of leaching are shown as follows:acid/ore mass ratio of 0.6:1,ore particle size less than 75μm of 84.2%,crap iron/ore of 1:1,liquid/solid of 6:1,leaching time of 100min,and leaching temperature of 25℃.Under these conditions,the leaching efficiency of manganese was 95.30%.(3)The impurities in the solution were removed by traditional method.The removal efficiencies of 99.99%for Cu and 88.40%for Pb were obtained under the conditions of actual dosage of iron powder/theoretical amount of 1.2,stirring time of 90min,temperature of 70℃.The aluminum removal efficiency reached 93.50%under the conditions of reaction temperature of 70℃,reaction time of 3h,pH value of 4.5,flocculant dosage of 2%(volume fraction).The removal efficiencies of 95.83%for Ca and 88.16%for Mg were obtained under the conditions of actual dosage of MnF2/theoretical amount of 1.4,pH value of about 4.5,reaction time of 2h and reaction temperature of 80℃.(4)The optimal conditions of co-precipitation process are shown as follows:pH value of 4.5,temperature of 60℃,time of 2h,stirring speed of 200r/min,actual ammonium oxalate dosage/theoretical dosage of 1.1 times,the adding method was positive order with the addition of glycol as dispersant.Under these concdictions,the precipitation efficiencies of manganese and iron were all above 98%.(5)The battery assembled by lithium manganese iron phosphate cathode material which is prepared by co-precipitation production has the better cycle performance,obvious discharge platform,but its specific capacity still needs to be improved.