Eudialyte
Formula: Na15Ca6(Fe,Mn)3Zr3SiO(O,OH,H2O)3
Mohs scale hardness: 5-6 Specific gravity: 2,74-3.10 g/cm3Eudialyte is used as a minor ore of zirconium. Eudialyte typically has a significant content of U, Pb, Nb, Ta, Zr, Hf, and rare earth elements (REE). Eudialyte is found associated with other alkalic igneous minerals, in addition to the some minerals common to most igneous material in general.Associate minerals include: microcline, nepheline, aegirine, lamprophyllite, lorenzenite, catapleiite, murmanite, arfvedsonite, sodalite, aenigmatite, rinkite, låvenite, titanite and titanian magnetite.Eudialyte's rarity makes locality useful in its identification. Prominent localities of eudialyte include Mont Saint-Hilaire in Canada and the Kola Peninsula in Russia, but it is also found in Greenland, Norway, and Arkansas. An interesting alternative source of HREE is eudialyte, a common zirconosilicate and principal ore mineral in a number of alkaline igneous REE ore deposits rich in HREE. It can be readily dissolved in different acids, making contained REE amenable to further hydrometallurgical processing.A principal HREE deposit with above mentioned zirconosilicates is the Norra Kärr deposit in Sweden, which is a peralkaline intrusion hosted rare earth element and zirconium mineralization with predominantly HREE bearing ore minerals such as eudialyte and catapleiite. Processing of the ore involves crushing, grinding and magnetic separation to obtain a REE bearing zirconosilicate (eudialyte) mineral concentrate and feldspar/nepheline and aegirine byproducts. The REE mineral concentrate is then sent to a sulphuric acid digestion followed by subsequent solid/liquid separation and further purification steps to finally obtain an REE carbonate and a zirconium bicarbonate product.
References
http://www.anzaplan.com/strategic-minerals-metals/rare-earth-minerals/rare-earth-minerals-processing/