Qiao X C, Poon C S, Cheeseman C
Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Waste Manag. 2006;26(2):141-9. doi: 10.1016/j.wasman.2005.02.020. Epub 2005 May 31.
Stabilization/solidification (S/S) processes have been used as the final treatment step for hazardous wastes prior to land disposal. Fly ash is a by-product of coal-fired power generation; a significant proportion of this material is low-grade, reject material (rFA) that is unsuitable as a cement replacement due to its high carbon content and large particle size (>45 microm). Flue gas desulphurization (FGD) sludge is a by-product from the air pollution control systems used in coal-fired power plants. The objective of this work was to investigate the performance of S/S waste binder systems containing these two waste materials (rFA and FGD). Strength tests show that cement-based waste forms with rFA and FGD replacement were suitable for disposal in landfills. The addition of an appropriate quantity of Ca(OH)2 and FGD reduces the deleterious effect of heavy metals on strength development. Results of TCLP testing and the progressive TCLP test show that cement-rFA-Ca(OH)2 systems with a range of FGD additions can form an effective S/S binder. The Leachability Index indicates that cement-based waste forms with rFA replacement were effective in reducing the mobility of heavy metals.
稳定化/固化（S/S）工艺已被用作危险废物土地处置前的最终处理步骤。粉煤灰是燃煤发电的副产品；这种材料的很大一部分是低品位的废弃材料（rFA），由于其高碳含量和大粒径（>45微米），不适合用作水泥替代品。烟气脱硫（FGD）污泥是燃煤电厂空气污染控制系统产生的副产品。这项工作的目的是研究包含这两种废料（rFA和FGD）的S/S废物粘结剂系统的性能。强度测试表明，用rFA和FGD替代的水泥基废物形式适合填埋处置。添加适量的Ca(OH)₂和FGD可降低重金属对强度发展的有害影响。TCLP测试结果和渐进TCLP测试表明，添加一系列FGD的水泥-rFA-Ca(OH)₂系统可形成有效的S/S粘结剂。浸出性指数表明，用rFA替代的水泥基废物形式可有效降低重金属的迁移率。
