Sulfation–Roasting–Leaching–Precipitation Processes for Selective Recovery of Erbium from Bottom Ash

Josiane Ponou, Marisol Garrouste, Gjergj Dodbiba, Toyohisa Fujita and Ji-Whan Ahn
Additional contact information
Josiane Ponou: Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
Marisol Garrouste: MINES ParisTech—PSL Research University, Rue Claude Daunesse, F-06904 Sophia Antipolis CEDEX, B.P. 207 1 Paris, France
Gjergj Dodbiba: Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
Toyohisa Fujita: School of Resources, Environment and Materials, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China, fujitatoyohisa@gxu.edu.cn
Ji-Whan Ahn: Korea Institute of Geoscience and Mineral Resources (KIGAM), 92 Gwahang-no, Yuseong-gu, Daejeon 305-350, Korea

Sustainability, 2019, vol. 11, issue 12, 1-11

Abstract: Bottom ash (BA) is mainly composed of compounds of Al, Fe, Ca, and traces of rare earth elements (REEs). In this study, the selective recovery of erbium (Er) as REEs by means of sulfation–roasting–leaching–precipitation (SRLP) using BA was investigated. A pre-treatment process of sulfation and roasting of BA was developed to selectively recover REEs using ammonium oxalate leaching (AOL) followed by precipitation. Most of the oxides were converted to their respective sulfates during sulfation. By roasting, unstable sulfates (mostly iron) decomposed into oxides, while the REE sulfates remained stable. Roasting above 600 °C induces the formation of oxy-sulfates that are almost insoluble during AOL. Dissolved REEs precipitate after 7 days at room temperature. The effects of particle size, roasting temperature, leaching time, and AOL concentration were the important parameters studied. The optimal conditions of +100–500 μm particles roasted at 500 °C were found to leach 36.15% of total REEs in 2 h 30 min and 94.24% of the leached REEs were recovered by precipitation. A total of 97.21% of Fe and 94.13% of Al could be separated from Er.

Keywords: bottom ash; sulfation; roasting; oxalic acid; rare earth; erbium; secondary raw material (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2019
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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