Decomposition of rare earth containing ores by alkaline hydrothermal process

Shoichi Toyoda*, Kimihisa Ito, Masanori Tokuda

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Xenotime, monazite and ion exchange ores were reacted with NaOH solution in the micro-autoclave under high temperature and pressure to produce a mixture of rare earth hydroxides. The decomposition reaction of phosphate ores such as xenotime and monazite required higher temperature and NaOH concentration than those for the decomposition of carbonatite ore, bastnaesite. The recovery of phosphate from the ores was limited by the solubility of Na3PO4 in the NaOH solution. The recovery of yittrium was decreased with the increase in the reaction temperature because the equilibrium phase changed from Y(OH)3 to YOOH above 610K, which was determined by the experiment.

Original languageEnglish
Pages (from-to)60-70
Number of pages11
JournalMetallurgical Review of MMIJ (Mining and Metallurgical Institute of Japan)
Issue number2
Publication statusPublished - 1995 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Metals and Alloys


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