Qilu University of Technology (Shandong Academy of Sciences), Advanced Materials Institute, Shandong Engineering Research Centre of Municipal Sludge Disposal, Jinan 250014, China.
Qilu University of Technology (Shandong Academy of Sciences), Advanced Materials Institute, Shandong Engineering Research Centre of Municipal Sludge Disposal, Jinan 250014, China.
Waste Manag. 2022 Apr 15;143:54-60. doi: 10.1016/j.wasman.2022.02.021. Epub 2022 Feb 24.
With an increase in municipal solid waste incineration (MSWI) fly ash and its dangerous characteristics, the manner of its disposal has caused widespread concerns. In this study, ceramsite was prepared by using MSWI fly ash, civil sludge, and contaminated soil as the main raw materials; then, a certain proportion of clay was added as an additive. The optimum MSWI fly ash content and sintering conditions were investigated, and the immobilization mechanisms of heavy metals were explored. Based on the obtained results, the optimum preparation conditions were a preheating temperature of 400 °C, a preheating time of 10 min, a sintering temperature of 1150 °C, and a sintering time of 20 min. Moreover, the optimal raw material ratio of MSWI fly ash, civil sludge, contaminated soil, and flint clay was 30%:40%:15%:15%. Under these optimum preparation conditions, the obtained ceramsite showed the following excellent performance parameters: a 1-h water absorption of 0.97%, bulk density of 998.7 kg/m, and cylindrical compressive strength of 37.84 MPa. Furthermore, the leaching of heavy metals was far less than the standard GB5085.3-2007. The immobilization of heavy metals in the ceramsite was mainly caused by the glass phase encapsulation and the formation of new crystal phase with the heavy metals. In addition, the generation of aluminosilicates played a positive role in the immobilization of heavy metals. Thus, the reuse of MSWI fly ash by preparing fly ash-based ceramsite is one of the effective methods for reducing solid wastes.
随着城市生活垃圾焚烧飞灰（MSWI 飞灰）的增加及其危险特性，其处置方式引起了广泛关注。本研究以 MSWI 飞灰、城市污泥和污染土壤为主要原料，添加一定比例的粘土作为添加剂，制备了陶粒。考察了最佳 MSWI 飞灰含量和烧结条件，探讨了重金属的固定化机理。在此基础上，确定了最佳的制备条件为预热温度 400°C、预热时间 10min、烧结温度 1150°C、烧结时间 20min；最佳原料配比为 MSWI 飞灰、城市污泥、污染土壤和硅质砂的比例为 30%：40%：15%：15%。在此最佳制备条件下，所制备的陶粒具有以下优异的性能参数：1h 吸水率为 0.97%、堆积密度为 998.7kg/m³、圆柱抗压强度为 37.84MPa。此外，重金属的浸出量远低于 GB5085.3-2007 标准。陶粒中重金属的固定化主要是由于玻璃相的包裹和与重金属形成新的晶体相。此外，铝硅酸盐的生成对重金属的固定化也起到了积极的作用。因此，通过制备粉煤灰基陶粒来利用 MSWI 飞灰是减少固体废物的有效方法之一。
