Institute of Geological Sciences, University of Bern, Switzerland; Zentrum für nachhaltige Abfall- und Ressourcennutzung (ZAR), Zuchwil, Switzerland.
Institute of Geological Sciences, University of Bern, Switzerland.
Waste Manag. 2018 Jun;76:457-471. doi: 10.1016/j.wasman.2018.03.022. Epub 2018 Mar 17.
Fly ash from municipal solid waste incineration contains a large potential for recyclable metals such as Zn, Pb, Cu and Cd. The Swiss Waste Ordinance prescribes the treatment of fly ash and recovery of metals to be implemented by 2021. More than 60% of the fly ash in Switzerland is acid leached according to the FLUWA process, which provides the basis for metal recovery. The investigation and optimization of the FLUWA process is of increasing interest and an industrial solution for direct metal recovery within Switzerland is in development. With this work, a detailed laboratory study on different filter cakes from fly ash leaching using HCl 5% (represents the FLUWA process) and concentrated sodium chloride solution (300 g/L) is described. This two-step leaching of fly ash is an efficient combination for the mobilization of a high percentage of heavy metals from fly ash (Pb, Cd ≥ 90% and Cu, Zn 70-80%). The depletion of these metals is mainly due to a combination of redox reaction and metal-chloride-complex formation. The results indicate a way forward for an improved metal depletion and recovery from fly ash that has potential for application at industrial scale.
城市固体废物焚烧飞灰中含有大量可回收金属，如 Zn、Pb、Cu 和 Cd。瑞士废物条例规定，到 2021 年，必须对飞灰进行处理并回收金属。瑞士超过 60%的飞灰采用 FLUWA 工艺进行酸浸，这为金属回收提供了基础。FLUWA 工艺的研究和优化越来越受到关注，瑞士正在开发一种直接从飞灰中回收金属的工业解决方案。本工作详细研究了使用 5%HCl（代表 FLUWA 工艺）和 300g/L 浓氯化钠溶液对飞灰浸出得到的不同滤饼。两步酸浸是一种从飞灰中高效提取重金属的组合工艺（Pb、Cd≥90%，Cu、Zn 70-80%）。这些金属的浸出主要是由于氧化还原反应和金属-氯化物配合物形成的综合作用。结果表明，从飞灰中提高金属浸出率和回收率的方法具有工业应用的潜力。
