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TitreEvaluation of rare Earth element-enriched sedimentary phosphate deposits using portable X-ray fluorescence (XRF) instruments
AuteurFajber, R; Simandl, G J
SourceGeological Fieldwork 2011; British Columbia Geological Survey, Geofile no. 2014-05, 2012 p. 199-210, 1 feuille
ÉditeurBC Ministry of Energy and Mines
Documentpublication en série
Mediaen ligne; numérique
Sujetsméthodes analytiques; terres rares; géochimie des terres rares; géochimie
ProgrammeÉtude des gîtes des métaux rares, Initiative géoscientifique ciblée (IGC-4)
LiensOnline - En direct (2.48 MB)
Résumé(Sommaire disponible en anglais seulement)
Sedimentary phosphate deposits (Mineral deposit profile F07; Simandl et al., 2012), consist mainly of the apatite group mineral [(Ca5(PO4)3 OH,F,Cl)] commonly referred to as francolite. Such deposits supply most of the phosphate rock used by the ammonia phosphate fertilizer industry. The 2010 world phosphate rock production is estimated at 176 million tonnes (Cordier, 2011). In recent years sedimentary phosphate deposits have also been considered as a potential fluorine resource (Simandl, 2009) and it is possible that rare earth elements (REE) may also be recovered from some sedimentary deposits as by-products (Simandl et al., 2011a, b). Portable XRF technology is relatively new. To the authors' knowledge there are no publicly available documents describing its use in the exploration and development of sedimentary phosphate deposits containing elevated concentrations of lanthanides and Y as by-products. Thirty-two samples of phosphate rock (pulps) from the Fernie Formation (southeastern British Columbia) were analysed using a hand-held XRF analyser as well as by a lithium metaborate fusion-inductively coupled plasma (LMBICPMS) method. The results from both methods were compared; correction factors for the portable XRF analyser were established and their effectiveness was tested. Portable hand-held XRF analysers that are currently on the market have their technical limitations. If correction factors are established, hand-held instruments can be used in exploration for phosphate deposits by analyzing samples directly for phosphorus (P), identifying zones of phosphate rocks rich in rare earth elements (REE), and delineating zones with unacceptable levels of deleterious elements such as uranium (U).