A research team led by Dr. Crawford Elliott at Georgia State University has identified impressive REE resources in Georgia kaolins. The Editor encountered interesting research work by Dr. Elliott and his team. Perhaps there is an opportunity for REE production in Georgia.
The high density siliciclastic minerals (e.g. zircon) in the coarse fractions (> 44 ?m, informally known as grit) of the mined Georgia kaolins are potential and significant sources of the rare-earth elements. This present study defined the contribution of these heavy minerals (e.g. zircon) to the rare-earth element (REE) inventory of the coarse fractions of Georgia Kaolins. Heavy mineral subfractions separated from the coarse fractions contained respectively 1,647 mg/kg REE from the Jeffersonville Member of the Lower Tertiary Huber Formation and 5,012 mg/kg REE from the Buffalo Creek Kaolin Member of the Upper Cretaceous Galliard Formation.
These heavy mineral subfractions were enriched 10-100 times in the heavy rare-earth elements (HREE, Gd-Lu,), Hf, and Zr relative to their concentrations of these elements in Upper Continental Crust. The heavy mineral subfractions comprised 5% of the coarse fractions (grit) of these two kaolin producing formations. The heavy mineral subfractions were composed of zircon, anatase, rutile, kaolinite, and minor amounts of muscovite and trace ilmenite and staurolite.
The high concentrations of REE were obtained by separating the dense heavy minerals from the coarse fraction (grit) obtained during the typical production of kaolin group minerals (kaolinite) from kaolin ore. The amount of zircon (6 – 11 wt.% per Zr elemental analyses) and absence of monazite did not explain the high concentrations of REE in the heavy mineral subfractions. The high amounts of REE could have resulted by the sorption of REE released during weathering reactions, or by the presence of small amounts (0.025 wt.%) each of monazite and xenotime in addition to the presence of zircon. This heavy mineral subfraction represented a novel domestic resource of extractable REE, especially the HREE, of a grade as high as 0.50 wt.% total REE.
Dr. Elliott is currently in his 23rd year of teaching at GSU. He served as Chair of Geosciences from 2007-2013. During that time, he led the consolidation of geology and geography disciplines forming Geosciences. Geosciences grew both in students, faculty members and extramural support for research during that time. Elliott has been funded by US DOE (both Basic Energy Sciences and Biological and Environmental Research) since Y2K. In addition to the recent work on REE, he, students and colleagues have done considerable work understanding the sorption of Cs by muscovite, illite and related phases. He is also collaborating with colleagues from Turkey to understand the genesis of bentonites in the Anatolia region. He is also working with Doug Elmore and colleagues to apply beam line techniques to understand the evolution of porosity in shales. He and Prof. Marion Wampler operate a K-Ar geochronology laboratory at GSU – perhaps the only operating K-Ar lab currently in the US. More details are below.
A New Look at the Occurrences of the Rare-Earth Elements in the Georgia Kaolins
Source: Clays and Clay Minerals
Publisher: The Clay Minerals Society