Selective Extraction of Rare Earth Elements from Monazite Ores with High Iron Content

  • Leandro Augusto Viana Teixeira
  • Ruberlan Gomes Silva
  • Angela Avelar
  • Daniel Majuste
  • Virginia S. T. CiminelliEmail author


Rare earth elements are essential for modern life products and green technologies. Recent supply constraints have boosted the development of rare earth projects after the price peak of 2011. The feasibility of a project depends on the definition of a processing route, which in turn depends primarily on the rare earth mineral, with monazite and bastnaesite representing the two most relevant minerals. Monazite-type ores usually contain high acid consumption impurities, such as iron, aluminum, calcium, magnesium, and phosphates, and may also contain prohibitive levels of radioactive thorium in its composition. This work presents a thermodynamic analysis of a monazite system and discusses the fundamentals of a selective process route for rare earth extraction from monazite ores with high iron content. This process involves sulfation by means of concentrated sulfuric acid and roasting at a high temperature. The route yields high rare earth extraction with low iron and thorium extractions and low acid consumption. Rare earth extractions as high as 80% were achieved, while iron and thorium extractions were lower than 1%, and acid consumption was lower than 0.34 kg of sulfuric acid per kg of ore. The operational window was compared to the one predicted by thermodynamic modeling, with 700 °C representing the optimal roasting temperature.


Rare earth extraction Monazite ore Sulfuric acid Selective roasting 



The authors would like to thank Vale S.A., especially Cassia Souza, Keila Gonçalves and Patrice Mazzoni for sample, material support, and the permission for publishing the results of this investigation. The authors are also thankful to Wagner Soares, Luzia Chaves, and Vale—CDM technicians, for their support in this work. V Ciminelli and D Majuste acknowledge the support from CNPq—Conselho Nacional de Desenvolvimento Científico e Tecnológico, CAPES—Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil—Finance Code 001, and FAPEMIG—Fundação de Amparo à Pesquisa de Minas Gerais.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.


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Copyright information

© Society for Mining, Metallurgy & Exploration Inc. 2019

Authors and Affiliations

  1. 1.Vale Mineral Development CentreSanta LuziaBrazil
  2. 2.Universidade Federal de Minas GeraisBelo HorizonteBrazil
  3. 3.National Institute of Science and Technology on Minerals Resources, Water and Biodiversity, INCT-AcquaBelo HorizonteBrazil

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