Minerals & Metallurgical Processing

, Volume 34, Issue 4, pp 201–206 | Cite as

Rare earths recovery and gypsum upgrade from Florida phosphogypsum

  • H. Liang
  • P. Zhang
  • Z. Jin
  • D. DePaoli
Special Issue on Rare Earths


Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P2O5), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C, REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P2O5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 µm, was separated from leached phosphogypsum through elutriation, in which the P2O5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum.

Key words

Rare earth elements Phosphogypsum Leaching efficiency Gypsum 


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Copyright information

© The Society for Mining, Metallurgy & Exploration 2017

Authors and Affiliations

  • H. Liang
    • 1
    • 2
  • P. Zhang
    • 2
  • Z. Jin
    • 2
  • D. DePaoli
    • 3
  1. 1.School of MetallurgyNortheastern UniversityShenyangChina
  2. 2.Florida Industrial and Phosphate Research InstituteFlorida Polytechnic UniversityBartowUSA
  3. 3.Oak Ridge National LaboratoryOak RidgeUSA

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