改性电解锰渣-矿粉复合胶材料的制备及水化机理

电解锰渣(EMR)是金属锰湿法冶炼过程中产生的一种固体废物，其堆积量大，对环境造成了严重的污染。但电解锰渣中富含硫酸盐，依据其特性，可与矿粉(GGBFS)复合制备胶凝材料。以矿粉为主要原料，电解锰渣为矿粉的硫酸盐激发剂，熟石灰为碱激发剂，制备电解锰渣-矿粉复合胶凝材料。探究电解锰渣、矿粉和熟石灰的最佳配比，并在此基础上对电解锰渣在不同温度下煅烧改性，通过力学测试确定最佳煅烧温度。利用XRD、FT-IR、TG-DTG和SEM等表征方式分析胶凝材料的水化产物及水化机理，同时对硬化体进行毒性测试。结果表明：电解锰渣对矿粉有良好的激发作用，复合胶凝材料中电解锰渣、矿粉、熟石灰最佳质量配比为2∶7∶1,其28 d的抗压强度达到27.2 MPa,电解锰渣经350℃煅烧所制备的复合胶凝材料抗压强度达到30.5 MPa。复合胶凝材料的水化产物主要为钙矾石(AFt)和水化硅酸钙(C-S-H);28 d硬化体浸出液中的重金属浓度均在《生活饮用水卫生标准》(GB 5749—2022)标准限值内，复合胶凝材料具有良好的安全性。

Preparation and Hydration Mechanism of Modified Electrolytic Manganese Slag - Mineral Powder Composite Cementitious Materials

Electrolytic manganese residue (EMR) is a kind of solid waste produced in the wet smelting process of manganese metal. The accumulation of EMR is large and causes serious pollution to the environment. However, EMR is rich in sulfate, and according to its characteristics, it can be combined with mineral powder (GGBFS) to prepare cementitious materials. With EMR as the main raw material, electrolytic manganese slag as sulfate exciter of mineral powder and hydrated lime as alkali exciter, electrolytic manganese slag - mineral powder composite cementitious material was prepared. The optimal ratio of EMR, GGBFS and hydrated lime was explored, and on this basis, the EMR was calcined and modified at different temperatures, and the optimal calcination temperature was determined by mechanical test. The hydration products and hydration mechanism of the cementitious materials were characterized and analyzed by XRD, FT-IR, TG-DTG and SEM, and the toxicity of the hardened body was tested. The results show that EMR has a good excitation effect on mineral powder, the optimum mass ratio of EMR, GGBFS and hydrated lime in the composite cementitious material is 2︰7︰1, its compressive strength of 28 d is 27.2 MPa, and the compressive strength of the composite cementitious material prepared by EMR calcined at 350 ℃ reaches 30.5 MPa. The hydration products of the composite cementitious material are mainly calcium alumina (AFt) and hydrated calcium silicate (C-S-H). The concentrations of heavy metals in leachate of the hardened body for 28 d are within the standard limits of “Standards for Drinking Water Quality：GB 5749—2022”, and the composite cementitious material has a good safety.