Title:
METHOD FOR RECOVERING RARE EARTHS FROM WASTE CERIUM-BASED RARE-EARTH POLISHING POWDER BY TWO-STEP ACID LEACHING STEPWISE SEPARATION
Document Type and Number:
WIPO Patent Application WO/2022/116870
Kind Code:
A1
Abstract:
The present invention relates to a method for recovering rare earths from waste cerium-based rare-earth polishing powder by two-step acid leaching stepwise separation, characterized by: first using primary acid leaching to treat a waste cerium-based rare-earth polishing powder, to obtain a leachate rich in the rare earth La; transforming the leaching residue by alkali activation, water washing, and removal of impurities, then performing secondary acid leaching, and filtering and recovering to obtain a high-purity CeO2 product; lastly, subjecting the pickle liquor obtained by the primary and secondary acid leaching to oxalic acid precipitation, filtration, and high-temperature calcination to obtain a mixed rare-earth oxide product, thus achieving stepwise separation and recovery of rare-earth elements from waste cerium-based rare-earth polishing powder. The total recovery of rare earth elements of the present invention is 97% or more, rare earth recovery is highly efficient, and the process is widely applicable and has low environmental pollution.
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Inventors:
ZHANG QIJUN (CN)
WU YUFENG (CN)
SONG MINWEI (CN)
WU YUFENG (CN)
SONG MINWEI (CN)
Application Number:
PCT/CN2021/132407
Publication Date:
June 09, 2022
Filing Date:
November 23, 2021
Export Citation:
Assignee:
UNIV BEIJING TECHNOLOGY (CN)
International Classes:
C01F17/229; C22B7/00; C22B1/02; C22B59/00
Foreign References:
| CN112725622A | 2021-04-30 | |||
| CN104232947A | 2014-12-24 | |||
| CN103103361A | 2013-05-15 | |||
| CN104946895A | 2015-09-30 | |||
| CN105039698A | 2015-11-11 | |||
| CN109207737A | 2019-01-15 | |||
| CA2631190A1 | 2009-11-02 | |||
| KR20040055219A | 2004-06-26 |
Attorney, Agent or Firm:
BEIJING SIHAI TIANDA INTELLECTUAL PROPERTY AGENCY LTD. (CN)
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