Lithium and manganese extraction from manganese-rich slag originated from pyrometallurgy of spent lithium-ion battery

Mn and Li were selectively extracted from the manganese-rich slag by sulfation roasting−water leaching.The extraction mechanisms of Mn and Li were investigated by means of XRD,TG−DSC,and SEM−EDS.73.71%Mn and 73.28%Li were leached under optimal experimental conditions:acid concentration of 82 wt.%,acid-to-slag mass ratio of 1.5:1,roasting temperature of 800°C,and roasting time of 2 h.During the roasting process,the manganese-rich slag first reacted with concentrated sulfuric acid,producing MnSO_(4),MnSO_(4)·H_(2)O,Li_(2)Mg(SO_(4))_(2),Al_(2)(SO_(4))_(3),and H_(4)SiO_(4).With the roasting temperature increasing,H_(4)SiO_(4) and Al_(2)(SO_(4))_(3) decomposed successively,resulting in generation of mullite and spinel.The mullite formation aided in decreasing the leaching efficiencies of Al and Si,while increasing the Li leaching efficiency.The formation of spinel,however,decreased the leaching efficiencies of Mn and Li.

Optimization of manganese-rich slag extraction from low-manganese ore smelting by response surface methodology

Manganese-rich slag is a raw material for smelting silicon–manganese alloys using an electric furnace.The blast furnace method is the main method for smelting manganese-rich slag.This method has the problems of a long process,large coke consumption,and easy volatilization of metals such as lead and zinc,which affects smelting safety.A new technology for smelting manganese-rich slag with low-manganese high-iron ore by smelting reduction optimization was proposed.This technology has the advantages of a short process,low energy consumption,low carbon emissions,and comprehensive recycling of lead,zinc,and other metals.According to the chemical composition,X-ray diffraction analysis,and particle size analysis of Cote d’Ivoire low-manganese ore,an experiment was carried out on manganese-rich slag by reduction–smelting separation.Combined with the design scheme of the Box–Behnken principle,three experimental factors(temperature,basicity,and carbon content)were selected as the influences to study.The influence that each factor has on the recovery rate of manganese was studied by response surface methodology,and the experimental factors were optimized.The results show that under the conditions of a reduction-smelting temperature of 1402℃,basicity of R=0.10,and carbon content of 10 mass%,the recovery rate of manganese is 97%.A verification experiment was carried out under the optimal conditions,and the error was only 1.24%;this proves that the response surface method prediction model is reliable and accurate.This is of great significance for the comprehensive utilization of lean-manganese ore resources.