Su Lijuan, Wu Siyao, Yu Feng, Zhu Wancheng, Zhang Xiangdong, Liang Bing
College of Civil Engineering, Liaoning Technical University, 47 Zhonghua Road, 123000, Fuxin, Liaoning, China.
College of Civil Engineering, Liaoning Technical University, 47 Zhonghua Road, 123000, Fuxin, Liaoning, China.
Environ Res. 2025 Feb 1;266:120594. doi: 10.1016/j.envres.2024.120594. Epub 2024 Dec 14.
Municipal solid waste incineration fly ash (MSWI FA) contains many harmful substances, such as heavy metals, which pose a great threat to the ecological environment. Its proper disposal is an urgent environmental problem that needs to be addressed. The large number of goaf areas in China's mines provides a new approach for MSWI FA treatment. Scientifically processed MSWI FA can be used for goaf filling; this reduces the stockpile of MSWI FA and improves the safety of mine goaf areas. In this study, paste backfill was prepared using MSWI FA and slag as cementitious materials and coal gangue as aggregates under the composite excitation of sodium hydroxide and water glass. The optimal mix ratio was determined using response surface methodology, and the leaching trend of the heavy metal ions inside the material and the micro mechanism of strength formation were studied. Molecular dynamics simulations were used to further examine the leaching pathways of the heavy metal ions. The experimental research showed that the optimal mix proportions of the backfill were 81.65%, 3.67% and 52.27% for the mass concentration, aggregate-to-cement ratio and fine gangue ratio, respectively. The main polymerization products were C-(A)-S-H and N-A-S-H silicate gel, and small amounts of ettringite (AFt), calcium aluminate chloride (3CaO • AlO • 3CaCl • 30HO) and CaCO were generated. Through Materials Studio (MS) software, the leaching pathway of the heavy metal ions in the backfill and the adsorption performance between the ions were examined, and the influence of the C-A-S-H gel on the leaching rates of the heavy metal ions of Pb, Cr, and Cd was explored. The leaching rate was ranked as Pb>Cr>Cd. In this study, a pollution-free and structurally stable mine paste backfill material was prepared using MSWI FA solid waste.
城市生活垃圾焚烧飞灰（MSWI FA）含有许多有害物质，如重金属，对生态环境构成巨大威胁。其妥善处置是一个亟待解决的环境问题。我国矿山大量的采空区为MSWI FA处理提供了新途径。经过科学处理的MSWI FA可用于采空区充填；这减少了MSWI FA的堆放量，提高了矿山采空区的安全性。本研究以MSWI FA和矿渣为胶凝材料，煤矸石为骨料，在氢氧化钠和水玻璃的复合激发作用下制备膏体充填料。采用响应面法确定了最佳配合比，并研究了材料内部重金属离子的浸出趋势和强度形成的微观机理。利用分子动力学模拟进一步研究了重金属离子的浸出途径。试验研究表明，充填料的最佳配合比为质量浓度81.65%、骨胶比3.67%、细矸石比52.27%。主要聚合产物为C-(A)-S-H和N-A-S-H硅酸盐凝胶，并生成少量钙矾石（AFt）、氯铝酸钙（3CaO•AlO•3CaCl•30H₂O）和CaCO₃。通过Materials Studio（MS）软件，研究了充填料中重金属离子的浸出途径及离子间的吸附性能，探讨了C-A-S-H凝胶对Pb、Cr、Cd重金属离子浸出率的影响。浸出率排序为Pb>Cr>Cd。本研究利用MSWI FA固体废物制备了一种无污染、结构稳定的矿山膏体充填料。
