Abstract:Electrolytic manganese anode slime (EMAS) from Xinjiang Aktao Kebang Manganese Industry Manufacturing Co., Ltd. is utilized as the experimental material. The sample exhibits a black-brown appearance with variable particle size. After drying to constant weight at 55°C, it is ground to a fineness of less than 50 mesh. Initially, the mineralogical characteristics were analyzed. Following dissolution in aqua regia at 300 °C and subsequent measurement by ICP-OES, the EMAS is found to contain 44.7% manganese and 6.0% lead respectively, indicating significant economic value. XRD analysis reveals that Mn and Pb exist primarily as (NH4)xMn8O16, MnO1.88 and PbSO4 in the EMAS, exhibiting low chemical reactivity, making conventional acid or alkali leaching ineffective. This conclusion is corroborated by SEM-EDS analysis, which show that the anode slime particles varied significantly in size, predominantly dense blocky structures with some honeycomb-shaped pores. Energy-dispersive spectroscopy indicates that Mn, Pb, O, and S coexist and constitute the main components of EMAS. The mass ratio of Mn to O is approximately 5﹕3, consistent with the standard MnO2 ratio. The synchronous variation in S and Pb content suggest the presence of PbSO4. Based on the wet reduction leaching process, glucose is selected as the reducing agent and sulfuric acid as the leaching agent. Single-factor experiments are conducted to investigate the effects of glucose-to-mineral ratio, acid-to-mineral ratio, liquid-to-solid ratio, leaching temperature, and leaching time on the leaching efficiency of manganese. The results demonstrate that under conditions of a mass ratio of EMAS﹕C6H12O6?H2O﹕H2SO4 of 1﹕0.125﹕1.2, liquid-to-solid ratio of 4﹕1 mL/g, leaching time of 120 minutes, and temperature of 95 °C, the leaching rate of Mn reaches 96.04%. The diffraction peaks of the leaching residue are sharp and narrow, indicating single-phase PbSO4. Compared to the raw ore, the diffraction peaks of (NH4)xMn8O16 and MnO1.88 disappear, confirming complete leaching of manganese and achieving a lead grade of 48.12%. Thermodynamic calculations of potential reactions during the leaching process were performed using HSC Chemistry. The ΔGθ T-T diagrams for relevant reactions show that glucose oxidation is spontaneous and proceeds through various pathways. In the early stages of the reaction, the carbon chain breaks down and converts into low-molecular-weight aldoses and formic acid, which the formic acid is further oxidized into carbon dioxide and water in later stages. However, as the reaction progresses from initial oxidation to completion, the ΔGθ T-T values gradually increase, making the reaction progressively more difficult and leading to incomplete organic reactions.