Monday, 8 January 2018

Problems in the processing of rare earths- the importance of mineralogy

Less than half a century ago the rare earth elements (REE) were classed as minor metals - who had even heard of neodymium, now essential in the production of powerful rare earth permanent magnets, used in wind turbines and many other applications?  Processing of REE now features in many major conferences, and in November, in Cape Town, MEI will introduce a new conference, Developments in the Processing of the "Hi-Tech" Metals (Hi-Tech Metals '18), where REE processing will be a major topic.
Hi-Tech Metals '18 immediately follows Process Mineralogy '18, the 5th in the series, and appropriately a keynote lecture at this conference will review common problems, and progress towards solutions, in the processing of REE.
The geochemistry and mineralogy of REE deposits is diverse and ranges from carbonatite-related deposits and alkaline rocks to mineral sands, ion adsorption clays, marine crusts, nodules and clays, by-products of phosphate and bauxite, and re-use of waste materials. Despite the large number of recent exploration projects, very little additional REE production has started. An in-depth understanding of the mineralogy is essential for process design and all of the deposit types have mineralogical advantages and challenges, which will be reviewed and explained in the keynote. For example, the deposits with the best established processing routes are monazite-bearing mineral sands but monazite radioactivity renders most unusable. Ion adsorption clays are easily leachable but deposits are low grade and shallow so new environmentally-friendly leaching techniques are needed. The diverse mineralogy of alkaline rocks has required development of processing routes for rare minerals such as steenstrupine and eudialyte. Carbonatites tend to have high proportions of the least valuable, lightest REE in REE fluorcarbonates or monazite. A deposit with two ore minerals, REE fluorcarbonate and apatite, that combine to give a REE profile close to that required by industry has an advantage if the ore minerals can be recovered efficiently.
The keynote lecture will be given by Frances Wall, Professor of Applied Mineralogy at the Camborne School of Mines (CSM), University of Exeter, UK. She has a BSc in Geochemistry and PhD from the University of London and worked on petrology and applied mineralogy at the Natural History Museum, London before joining CSM in 2007. Her research interests include the geology, applied mineralogy, processing, and responsible sourcing of critical raw materials. Frances currently leads two large international projects: SoS RARE and HiTech AlkCarb, was Head of CSM from 2008-2014, and was named one of the 100 Global Inspirational Women in Mining 2016.

6 comments:

  1. Apatite, thorite, fluorite, brockite occurrence are unpromising for the production of REE

    They write: "The diverse mineralogy of alkaline rocks has required development of processing routes for rare minerals such as steenstrupine and eudialyte"

    1. Steenstrupine contains thorium. This means it is radioactive.
    Eudialyte typically has a significant content of uranium. This means it is radioactive.
    Steenstrupine and eudialyte are radioactive.
    What is the advantage of steenstrupine and eudialyte? The answer is obvious, that no.

    2. Steenstrupine contains 27 % REE (Ce). eudialyte contains 10 % REE.
    You can not sell what poor concentrate!
    Monazite contains 70 % REE. Bastnaesite contains 75 % REE. What is the advantage of steenstrupine and eudialyte? The answer is obvious, that no.

    3. They do not have technology for processing Steenstrupine and .eudialyte. The development of technology can take dozens of years.
    What is the advantage of steenstrupine and eudialyte? The answer is obvious, that no. Technologies for the processing of monazite and bastnaesite exist (They need to be improved).

    4. Prominent localities of eudialyte include the Kola Peninsula in Russia, Greenland (Norway, Canada). Prominent localities of steenstrupine include the Kola Peninsula in Russia, Greenland.
    What is the advantage of steenstrupine and eudialyte? The answer is obvious, that no.
    A harsh climate, remoteness creates additional costs

    They write: " A deposit with two ore minerals, REE fluorcarbonate and apatite"
    1. Fluorcarbonate is not a mineral, it is a mineral group.
    2. Apatite does not form REE deposits.

    This is a deception, which has become a classic.

    Ph.D. Natalia Petrovskaya http://gladiolus1.blogspot.cl/2018/01/under-guise-of-ree-deposits-they-can.html

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    Replies
    1. In the world there is a shortage of these REE: Y, Dy, Nd, Eu, Tb.
      The increase in production volumes La, Ce leads to lower prices for these metals.
      They offer us to extract the cerium mineral - Steenstrupine. Cerium is enough.

      Delete
    2. There are more than 110 minerals containing the Cerium (Ce). 40 of them contain more Cerium than Steenstrupine.
      Why Steenstrupine?

      Delete
    3. I must compliment that this information and discussion has shown the new challenges to mineral engns; reminded how important mineralogy study is to processing.
      I hope there are more of these kind of new insights .
      Very good,Barry.
      Rao,T.C.

      Delete
  2. Thank you for your comment, Natalia. I hope you will be able to come to the conference where I will explain the advantages and disadvantages of the various types of REE ore deposits, especially from the process mineralogy point of view. One reason for the recent interest in alkaline rocks is because they tend to have higher proportions of the heavy REE than carbonatite-related deposits. Here are two recent papers that may be of interest:

    Wall F, Rollat A, Pell R. (2017) Responsible sourcing of critical metals, Elements, volume 13, number 5, pages 313-318, DOI:10.2138/gselements.13.5.313

    Goodenough KM, Wall F, Merriman D. (2017) The Rare Earth Elements: Demand, Global Resources, and Challenges for Resourcing Future Generations, Natural Resources Research, DOI:10.1007/s11053-017-9336-5.

    The fluorcarbonate (synchysite) - apatite pair I mentioned in the abstract is at Songwe Hill, Malawi, see http://www.mkango.ca/s/songwe.asp

    Frances Wall

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    Replies
    1. Hello. Frances
      Can you share what classification of minerals do you use?
      You write that "The fluorcarbonate (synchysite) - apatite".
      However, on all sites that I have at, it says "Synchysite is a group of carbonate mineral. Apatite is a group of phosphate minerals".

      Delete

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