ABSTRACT：Municipal solid waste incineration (MSWI) fly ash usually needs to undergo dechlorination or heavy metal stabilization pretreatment for further treatment, recycling or disposal. In this paper, the removal effect of chlorine in fly ash by water washing, lactic acid, citric acid and microwave treatment was studied, and XANES was used to analyze chlorine chemical form in fly ash. In addition, the heavy metals in fly ash were also checked. The results indicated that double washing and triple washing could remove 88.0 % and 95.5 % of chlorine from fly ash respectively. The “doublewater washing + microwave/organic acid” could remove about 96.6 % of chlorine, and 42.9 % and 47.2 % of insoluble chloride respectively. The microwave treatment could maximize the stabilization of heavy metals with a BI value of 39.1 %, 0.11 %, 1.65 %, 15.4 % and 3.98 % for Cd, Cr, Cu, Pb and Zn. The elution of heavy metals by citric acid was obvious. “Double water washing + citric acid” removed 87.0 % of Cd, 17.2 % of Cr, 11.9 % of Cu, 39.6 % of Pb and 43.6 % of Zn, but the environmental risk of Cu and Cr increased about 2–3 % after the treatment. The results of this study provide guidance for the pretreatment of fly ash before resource utilization.

KEYWORDS:MSWI fly ash,Organic acid,Microwave, Chlorine, Heavy metals

摘要：城市生活垃圾焚烧飞灰通常需要进行脱氯或重金属稳定化预处理，以便进一步的处理、回收或处置。本文研究了水洗、乳酸、柠檬酸和微波处理对飞灰中氯的去除效果，并用XANES分析了飞灰中氯的化学形态。此外，还对飞灰中的重金属进行了检测。结果表明，两次水洗和三次水洗对飞灰中氯的去除率分别为88.0%和95.5%。“两次水洗+微波/有机酸”工艺对氯盐的去除效率约为96.6%，且对不溶性氯盐的脱除效率分别为42.9%和47.2%。微波处理对重金属的稳定化效果最好，处理后重金属Cd、Cr、Cu、Pb和Zn的BI值分别为39.1%、0.11%、1.65%、15.4%和3.98%。而柠檬酸对重金属有明显的洗脱作用。“两次水洗+柠檬酸”去除了87.0%的Cd、17.2%的Cr、11.9%的Cu、39.6%的Pb和43.6%的Zn，但处理后Cu和Cr的环境风险增加了约2-3%。本研究结果为飞灰资源化利用的前处理提供了指导。

关键词：垃圾焚烧飞灰，有机酸，微波，氯，重金属

原载：Science of the Total Environment（2023 Impact Factor = 10.754）

原文链接：https://doi.org/10.1016/j.scitotenv.2023.161929