Extraction of lanthanides from the phosphoric acid production process to gain a purified gypsum and a valuable lanthanide by-product

C. Koopman*, G. J. Witkamp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

In the HemiDiHydrate (HDH) phosphoric acid production processes, calcium sulfate hemihydrate (HH) is formed from the reaction of fluoroapatite ore with sulfuric acid, after which it is recrystallized into calcium sulfate dihydrate (DH, gypsum). Some impurities from the feedstock are incorporated in the HH during the first reaction and finally end up mainly in the sparingly soluble gypsum. By introducing ion exchange resin during the phosphoric acid-mediated recrystallization, lanthanides that are dissolved from the HH can be removed from the acid before they become incorporated again in the gypsum. With 250 g resin/kg phosphoric acid slurry, lanthanides were removed to up to 53% of the input. The resulting decrease of the lanthanide concentration in the gypsum is lower, up to 34%. The extraction efficiency is influenced by the recrystallization reaction. Lanthanides that are most readily taken up by the gypsum are extracted least. Although the sulfonic acid resin has a preference for the trivalent lanthanides, calcium ions are also extracted.

Original languageEnglish (US)
Pages (from-to)51-60
Number of pages10
JournalHydrometallurgy
Volume58
Issue number1
DOIs
StatePublished - Jan 1 2000
Externally publishedYes

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry

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