Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Road, Da-an District, Taipei City 10673, Taiwan.
Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Zhongxiao E. Road, Taipei City 10608, Taiwan.
Waste Manag. 2021 Feb 15;121:412-421. doi: 10.1016/j.wasman.2020.12.031. Epub 2021 Jan 11.
Municipal solid waste incineration fly ash (MSWI-FA) has been regulated as a hazardous waste that needs to treat with stabilization, solidification and landfill due to its amount of heavy metals, chlorides, sulfates and dioxin. While the proper treated MSWI-FA can be utilized as pozzolanic material to reduce the usage of Portland cement. The present article aims to develop an integrated wet-extraction and carbonation process for MSWI-FA stabilization, solidification and utilization via the high-gravity technology. A benchtop experiment demonstrated the dechlorination and CO sequestration of MSWI-FA and the carbonated product was applied as a supplementary cementitious material (SCM) in the cement mortar. Physical, chemical and thermal characteristics of raw, wet-extracted, and carbonated MSWI-FA were addressed in terms of the mean diameter, micropore area, micropore volume, chemical compositions, mineralogy and morphology. The effects of the liquid-to-solid ratio and high gravity factor were evaluated. Overall, a chloride extraction ratio of 36.35% and a CO capture capacity of 258.5 g-CO kg-FA were achieved in the batch experiment. The results of water-energy consumption of chloride removal and CO fixation provided a novel insight into the future process criterion. In addition, the carbonated FA was found as binder to partially substitute Portland cement due to its large content of calcium carbonate. The workability and mechanical strength of cement mortar with partial substitution of stabilized FA were evaluated to determine the potential FA utilization pathway. Finally, the continuous process tests determined the key operation indexes for future process scale-up.
城市固体废物焚烧飞灰（MSWI-FA）由于其重金属、氯化物、硫酸盐和二恶英的含量而被规定为危险废物，需要进行稳定化、固化和填埋处理。而经过适当处理的 MSWI-FA 可以用作火山灰材料，以减少 Portland 水泥的用量。本文旨在通过高重力技术开发一种用于 MSWI-FA 稳定化、固化和利用的综合湿法提取和碳化工艺。一项台式实验演示了 MSWI-FA 的脱氯和 CO 捕集，并且碳化产物被用作水泥砂浆中的补充胶凝材料（SCM）。从平均粒径、微孔面积、微孔体积、化学成分、矿物学和形态等方面研究了原始、湿法提取和碳化 MSWI-FA 的物理、化学和热特性。评估了液固比和高重力因子的影响。总体而言，在批处理实验中实现了 36.35%的氯化物提取率和 258.5 g-CO kg-FA 的 CO 捕获能力。去除氯化物和固定 CO 的水-能消耗的结果为未来的工艺标准提供了新的见解。此外，由于含有大量的碳酸钙，碳化 FA 被发现可作为部分替代 Portland 水泥的粘结剂。评估了部分替代稳定化 FA 的水泥砂浆的工作性和力学强度，以确定潜在的 FA 利用途径。最后，连续过程测试确定了未来工艺放大的关键操作指标。
