State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China.
School of Civil Engineering, Harbin Institute of Technology, Harbin, 150090, China.
J Environ Manage. 2024 Dec;371:123023. doi: 10.1016/j.jenvman.2024.123023. Epub 2024 Oct 30.
Municipal solid waste incineration fly ash (MSWI FA) is a globally recognized hazardous waste. This study developed a low-carbon and high-compatibility calcium sulfoaluminate-enhanced ternary binders (PCG) composed of calcium sulfoaluminate cement, ordinary Portland cement and granulated blast-furnace slag for the stabilization/solidification (S/S) of MSWI FA. The complex interaction mechanisms between PCG binders and typical potentially toxic elements (PTEs, e.g., Pb and Cr) were investigated. Experimental results revealed that the various components in PCG synergically changed the content, type, and structure of calcium-aluminum-silicate-hydrate (C-A-S-H) phase and aluminate products, enhancing their immobilization efficiency to various PTEs. X-ray diffraction results revealed PTEs were captured by C-A-S-H via surface complexation effect, and Cr was further immobilized by aluminate products due to the ion substitution of CrO to SO. Mercury intrusion tests demonstrated the generation of hydration products exhibited positive effects on the physical coating effect of designed binders to PTEs. Subsequent practical S/S experiments demonstrated satisfactory mechanical properties (over 20 MPa) and acceptable PTEs leachability of PCG-based S/S blocks, fulfilling the criteria of low-carbon construction materials. Life cycle assessment results revealed, compared to single ordinary Portland cement, the adoption of PCG binders for S/S of MSWI FA achieved a 60% reduction in carbon emissions. Overall, this study contributed to the advancement of S/S methodologies for MSWI FA and underscored the environmental advantages in employing low-carbon PCG binders in hazardous waste treatment.
城市生活垃圾焚烧飞灰（MSWI FA）是一种被全球公认为危险废物。本研究开发了一种低碳且高兼容性的钙矾石增强三元胶凝材料（PCG），由钙矾石水泥、普通硅酸盐水泥和粒化高炉矿渣组成，用于 MSWI FA 的稳定/固化（S/S）。研究了 PCG 胶凝材料与典型的潜在有毒元素（PTEs，如 Pb 和 Cr）之间的复杂相互作用机制。实验结果表明，PCG 中的各种成分协同改变了钙铝硅酸盐水化物（C-A-S-H）相和铝酸盐产物的含量、类型和结构，提高了它们对各种 PTEs 的固定效率。X 射线衍射结果表明，PTEs 通过表面络合作用被 C-A-S-H 捕获，而 Cr 则进一步被铝酸盐产物固定，因为 CrO 取代了 SO。压汞试验表明，水化产物的生成对设计胶凝材料对 PTEs 的物理涂覆效果有积极影响。随后的实际 S/S 实验表明，PCG 基 S/S 块具有令人满意的力学性能（超过 20 MPa）和可接受的 PTEs 浸出性，满足低碳建筑材料的标准。生命周期评估结果表明，与单一普通硅酸盐水泥相比，采用 PCG 胶凝材料进行 MSWI FA 的 S/S 可将碳排放减少 60%。总体而言，本研究为 MSWI FA 的 S/S 方法提供了新的思路，并强调了在危险废物处理中采用低碳 PCG 胶凝材料的环境优势。
