Extraction 2018 pp 2633-2645 | Cite as

A Comparison Between Batch and Continuous Processes in Impurity Removal from REE Water Leach Solution by Lime and Limestone Neutralization

  • Farzaneh SadriEmail author
  • Zhi Yang
  • Ahmad Ghahreman
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


After water leaching of an acid baked REE concentrate, impurities such as Fe, Al, Th, and Cu are removed by neutralization with different reagents such as NaOH, Mg(OH)2, MgCO3, CaO, and CaCO3. Among these chemicals, lime (CaO) and limestone (CaCO3) are the preferred reagents due to their low costs. However, because of calcium sulfate dihydrate (gypsum) precipitation, they are not so common in industry. One of the disadvantages of gypsum precipitation is the adsorption of REE to the precipitates, losing a fraction of REE to gypsum which is hard to recover. In this paper, batch and continuous conditions in the impurity removal process using limestone are investigated and the differences between these two processes are examined. Based on the experiments, REE uptake by gypsum significantly increases in continuous processes, and different gypsum morphologies are observed.


Rare Earth Elements (REE) Continuous Batch Lime Limestone Precipitation 



The authors would like to acknowledge the financial support for this study through NSERC.


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Copyright information

© The Minerals, Metals & Materials Society 2018

Authors and Affiliations

  1. 1.Department of Mining EngineeringQueen’s UniversityKingstonCanada

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