Coordination-enhanced extraction of rare earth metals from waste polishing powder and facile preparation of a mesoporous Ce-La oxide

He, Xiaofeng; Chen, Lin; Chen, Peng; Liu, Weifeng; Zhang, Duchao; Yang, Tianzu

doi:10.1016/j.cej.2022.139265

Cited by 9 publications

(5 citation statements)

References 39 publications

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“…Labels u 0 , u , u ′, u ″, and u ‴ are associated with Ce 3d 3/2 , while v , v ′, v ″, and v ‴ belong to Ce 3d 5/2 . According to the reports, ,, v , v ″, v ‴, u , u ″, and u ‴ are assigned to the CeO 2 (Ce 4+ states) (Ce 4+ = v + v ″ + v ‴ + u + u ″ + u ‴), while v ′, u 0 , and u ′ correspond to Ce 2 O 3 (Ce 3+ states) (Ce 3+ = v ′ + u 0 + u ′). These results reveal that the Ce element is present in both 3+ and 4+ oxidation states in the original CPPW and mechanochemistry products .…”

Section: Resultsmentioning

confidence: 99%

“…With a rotary speed of 0 rpm, the extraction efficiencies of La, Ce, and REOs are considerably low, registering at only 66.18%, 24.26%, and 38.91%, respectively. This suggests that the rare-earth components in the CPPW exhibit marked resistance to dissolution in HCl solution, especially for Ce, with very low leaching efficiency, which is consistent with some previous literature . However, a marked improvement is observed at 100 rpm, with efficiencies rising to 92.13%, 75.6%, and 83.86% for La, Ce, and REOs, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…This suggests that the rare-earth components in the CPPW exhibit marked resistance to dissolution in HCl solution, especially for Ce, with very low leaching efficiency, which is consistent with some previous literature. 3 However, a marked improvement is observed at 100 rpm, with efficiencies rising to 92.13%, 75.6%, and 83.86% for La, Ce, and REOs, respectively. As the rotary speed escalates to 300 rpm, the extraction efficiencies of La, Ce, and REOs peak at 98.99%, 97.42%, and 98.08%, respectively.…”

Section: Mechanochemistry and Acid Leaching Parameters Optimization A...mentioning

confidence: 95%

“…Statistics indicate that China generates close to 1,500,000 tons of the CPPW annually, which unfortunately ends up in landfills . Notably, rare-earth oxides (REOs), primarily CeO 2 and trace amounts of La 2 O 3 , Pr 6 O 11 , and Nd 2 O 3 , constitute 40–60 wt % of the total CPPW . The CPPW also contains potentially harmful elements such as F and Pb .…”

Section: Introductionmentioning

confidence: 99%

“…2 Notably, rare-earth oxides (REOs), primarily CeO 2 and trace amounts of La 2 O 3 , Pr 6 O 11 , and Nd 2 O 3 , constitute 40−60 wt % of the total CPPW. 3 The CPPW also contains potentially harmful elements such as F and Pb. 4 Hence, recycling CPPW not only aids in conserving rare-earth resources but also stands as a pivotal step toward environmental preservation.…”

Section: Introductionmentioning

confidence: 99%

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Kilogram-Scale Recovery of La/Ce and Regeneration of Rare-Earth Polishing Powder Products from Ceria-Based Polishing Powder Waste

Wu,

Song,

Hao

et al. 2024

ACS Sustainable Resour. Manage.

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Large quantities of hazardous ceria-based polishing powder waste (CPPW) are produced worldwide each year, much of which unfortunately ends up in landfills, causing waste of rareearth resources and harm to the environment. This study proposes a novel mechanochemical approach for the recovery of La and Ce from CPPW and the regeneration of rare-earth polishing powders. The mechanochemical process facilitates the breakdown of the insoluble components of the CPPW (CeO 2 , CeLa 2 O 3 F 3 , LaF 3 ), enabling the leaching of 99.2% of La, 97.85% of Ce, and 98.53% of REOs. A comprehensive examination of the potential mechanochemical enhancement of rare-earth extraction mechanisms reveals that mechanochemistry can achieve the reduction of Ce(IV) to Ce(III) under non-high-temperature and high-pressure conditions, which can significantly enhance the leaching efficiency of Ce from CPPW. In order to ascertain the reason why the simultaneous leaching of La and Ce in the product could not be achieved, the leaching kinetics of La and Ce were simulated and discussed separately. After mechanochemical and acid leaching, the La,Ce-enriched leachate was separated and purified, for efficiently removing impurities (Si, Al, Na, Ca, Mg, Fe, etc.), and thus, 99.2 wt % purity of rare-earth polishing powder (CeO 2 and LaOF mixture) products were successfully regenerated. The chemical mechanical polishing results show that the as-regenerated rare-earth polishing powder exhibits excellent polishing performance and fulfils the requirements of commercial quality. This methodology presents a practicable solution for green, large-scale, efficient, and economical recovery of rare earths from the CPPW.

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