Removing water-soluble chlorides (WSCs) through water extraction is a common pretreatment technology for recycling municipal solid waste incineration (MSWI) fly ash (FA). However, the extracted solution often contains heavy metals, the concentrations of which exceed standards for effluent. This study aims to investigate the adsorption of heavy metals by palygorskite in water-extracted solution and explore the feasibility of stabilizing heavy metals through comilling palygorskite-adsorbed heavy metals (PAHMs) with water-extracted fly ash (WFA). The experimental parameters include: two-stage water extraction with a liquid-to-solid ratio of 5, adding 0, 0.125, 0.25, 0.5, 1, 2 or 3 g of palygorskite to 100 mL of water-extracted solution, and comilling the mixture of PAHMs and WFA for 0, 0.5, 1, 2, 4, 8, 12, 24 or 96 hours. The experimental results revealed that 3 g of palygorskite in 100 mL of extracted solution could absorb Pb, Cd, Cr, Cu and Zn, meeting the effluent standards. The total amount of Pb, Cd, Cr, Cu and Zn removal rate reached 99.7%. Moreover, 98.44% of the WSCs were not adsorbed, the water extraction process for removing WSCs was not compromised. After the comilling of PAHMs and WFA, the distribution of the heavy metals in the milled blended powder was greater than 99.44%; moreover, toxicity characteristic leaching procedure concentrations were determined to conform to regulatory standards, and the sequential extraction procedure revealed that the heavy metals tended to be in stable fractions. This achieves the goal of preventing secondary pollution from heavy metals during the MSWI FA recycling process.

中文翻译：

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凹凸棒石吸附和共磨稳定去除水提液中的重金属

通过水萃取去除水溶性氯化物（WSC）是回收城市固体废物焚烧（MSWI）飞灰（FA）的常用预处理技术。然而，提取的溶液中往往含有重金属，其浓度超出了废水标准。本研究旨在研究水提溶液中凹凸棒石对重金属的吸附作用，并探索通过将凹凸棒石吸附的重金属（PAHMs）与水提粉煤灰（WFA）共研磨来稳定重金属的可行性。实验参数为：液固比为5的两级水提取，向100mL水提取液中加入0、0.125、0.25、0.5、1、2或3g凹凸棒石，共研磨。 PAHM和WFA的混合物0、0.5、1、2、4、8、12、24或96小时。实验结果表明，100 mL萃取液中3 g凹凸棒石可吸附Pb、Cd、Cr、Cu、Zn，满足出水标准。 Pb、Cd、Cr、Cu、Zn总量去除率达到99.7%。此外，98.44%的WSC没有被吸附，去除WSC的水提取过程没有受到影响。 PAHMs和WFA共研磨后，研磨后的混合粉末中重金属的分布大于99.44%；此外，确定浸出程序的毒性特征浓度符合监管标准，并且连续提取程序表明重金属往往处于稳定的组分中。达到了防止垃圾焚烧发电厂回收过程中重金属二次污染的目的。