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Miner Deposita (2014) 49:967986 DOI 10.1007/s00126-014-0542-3
ARTICLE
The rare earth element potential of kaolin deposits in the Bohemian Massif (Czech Republic, Austria)
S. Hhn & H. E. Frimmel & J. Paava
Received: 10 December 2013 /Accepted: 11 July 2014 /Published online: 8 August 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Four kaolin deposits in the Bohemian Massif were studied in order to assess the potential for the recovery of rare earth elements (REE) as by-products from the residue after extraction and refining of the raw kaolin. The behaviour of REE + Y during kaolinitization was found to be largely a function of pre-alteration mineralogy. In the examples studied,i.e. granite-derived deposits of Kriechbaum (Austria) and Boiany, and arkose-derived deposits of Kaznjov and Podboany (all Czech Republic), the REE + Y are predominantly hosted by monazite which has remained unaffected by kaolinitization. The overall REE + Y content of the variably kaolinitized rocks is strongly dependent on their genesis. While ion adsorption plays only a minor role in the concentration of REE + Y in the studied kaolinitized rocks, the processing and refining of the raw kaolin leads to residues that are enriched in REE + Y by a factor of up to 40. The use of a magnetic separator and a hydrocyclone in the processing of the raw material can yield REE + Y contents of as much as0.77 wt%. Although this value compares well with the REE + Y concentration in some potentially economic REE + Y projects elsewhere, the overall tonnage of the (REE + Y)-enriched residue is by far not sufficient to consider economic extraction of REE + Y as by-product. Our results are most
probably applicable also to other kaolin deposits derived from the weathering of Hercynian basement granites elsewhere (e.g. in Saxonia and Bavaria, Germany). Overall, the potential for REE + Yproduction as by-product from kaolin mining has to be regarded as minimal.
Keywords Rare earth elements . Kaolin . Bohemian Massif . Granite weathering
Introduction
Over the past few decades, rare earth elements and Y (REE + Y) have become critical raw materials in the fabrication of a range of products, many of which are considered high-tech products. The global supply with REE + Y gained widespread attention in the...