The effect of mechanical grinding and thermal treatment on the recovery of rare earth elements (REEs) from kaolinite

Bin Ji, Wencai Zhang

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

REE recovery from a kaolinite sample was conducted in the present study. The results of mineralogical analyses, salt leaching, and acid leaching tests confirmed that REEs predominantly existed as florencite (REEAl3(PO4)2(OH)6) in the material, and the proportion of ion-exchangeable and ion-substituted REEs was negligible. Mechanical grinding for 4 h completely destroyed the crystal structure of the material, but the recovery of total REEs was less than 20%, indicating that insufficient liberation of the REE-bearing particles is not the only factor leading to the low recovery. Thermal treatment of the raw material at 600 °C for 2 h largely enhanced the total REE recovery to as high as 92%. The improved recovery was ascribed to the thermal decomposition of crystallized florencite into an amorphous phase, which was proved through transmission electron microscopy - energy dispersive X-ray analysis. Findings from the study will contribute to REE recovery and comprehensive utilization of kaolinite.

Original languageEnglish
Pages (from-to)622-631
Number of pages10
JournalPowder Technology
Volume394
DOIs
StatePublished - Dec 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Calcination
  • Clay
  • Grinding
  • Rare earth elements
  • Recovery

ASJC Scopus subject areas

  • General Chemical Engineering

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