Optimizing critical metals recovery and correlative decontamination from MSWI fly ash: Evaluation of an integrating two-step leaching hydrometallurgical process
Journal article, 2022

While municipal solid waste incineration (MSWI) fly ash is classified as hazardous waste, it can also serve as an urban mining source for numerous precious metals. Of particular interest are antimony (Sb) and zinc (Zn); the former of which is a strategic and critical metal that is being rapidly depleted, putting society at high risk for supply shortages. In this work, a two-step leaching method for recovering Sb and Zn from MSWI fly ash is proposed. Furthermore, the leaching behavior and adsorption mechanism of Sb in the MSWI fly ash waste stream were also investigated. Results from the first constant pH leaching tests (CPLT) showed that under diluted acidic condition, the maximum amount of Sb released from fly ash was ∼20%. In addition, at pH 4.0, 67% of the fly ash was dissolved, while 79.3% and 12.1% of the Zn and Sb, respectively, were recovered. After optimizing and executing a second Sb leaching procedure (6 M HCl solution at 60 °C), >80% of the Sb was recovered. Thus, the proposed two-step leaching process, consisting of extraction followed by decontamination using a magnetic HAP@CoFe2O4 adsorbent, can eliminate the Sb in fly ash effluent with a removal efficiency >95%. Moreover, this process produces less toxic products and lowers the effluent residue concentration. As such, the two-step process described herein is suggested for Sb and Zn recovery from fly ash; as it not only enables precious metal recovery, but also aids in treating secondary waste streams produced from urban mining.

Author

Jinfeng Tang

Linköping University

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Shaobin Dong

Linköping University

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Qian Feng

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Linköping University

Minhua Su

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Linköping University

Yongjun Wei

Zhengzhou University

Jiawei Liang

Zhengzhou University

Hongguo Zhang

Linköping University

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Lei Huang

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Linköping University

Lingjun Kong

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Linköping University

Nana Wang

Linköping University

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Enzong Xiao

Linköping University

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Yingkui Liu

XuZhou Medical University

Xuan Tang

Guangzhou University

Tangfu Xiao

Linköping University - Guangzhou University Research Center on Urban Sustainable Development

Linköping University

Journal of Cleaner Production

0959-6526 (ISSN)

Vol. 368 133017

Subject Categories

Chemical Process Engineering

Other Chemistry Topics

Bioenergy

DOI

10.1016/j.jclepro.2022.133017

More information

Latest update

8/2/2022 9