Volkswagen bundling all intelligent driver assistance technologies under new umbrella brand IQ.DRIVE; heading to autonomy
24M raises $21.8M to accelerate SemiSolid battery development and deployment; round led by Kyocera and ITOCHU

Georgia kaolin mines are potential sources of rare-earth elements

The high-density minerals in the Georgia kaolin mines are potential sources of rare-earth elements, including the heavy rare-earth elements that are in high demand for many important uses and are mostly imported to the United States from China, according to a study led by Georgia State University and Thiele Kaolin Co. Kaolin is a type of clay.

Rare-earth elements are used to make critical products, including rechargeable battery electrodes and permanent magnets.

There are 17 rare-earth elements, which include the 15 elements of the lanthanide series (atomic numbers 57 to 71 on the periodic table), plus scandium (Sc) and yttrium (Y). The heavy rare-earth elements are from gadolinium (Gd) to lutetium (Lu), atomic numbers 64 to 71 on the periodic table.

Thiele Kaolin Co. mined for kaolin in two quarries near Sandersville, Ga., and provided Georgia State researchers with the leftover mineral samples, or grit, for analysis. The minerals present were identified using X-ray diffraction, scanning electron microscopy and chemical analysis. The findings, published in the journal Clays and Clay Minerals, suggest a new, potential source of rare-earth elements, including the less common heavy rare-earth elements.

We were interested in looking at the very course, sand-sized material from the kaolin ore that they call grit. It accounts for about 10 percent of the mined material and is removed before they make finished kaolin products for a variety of applications, such as paper, paints, adhesives, plastics, ceramics, etc. They gave us samples of the grit. When we processed these samples, we found a particular enrichment in the heavy rare-earth elements, gadolinium through lutetium. An enrichment in the heavy rare-earth elements is interesting and useful because in most cases, the Earth’s crust is enriched in the lighter rare-earth elements. The heavy rare-earth elements tend to be more technologically important.

After we did a heavy liquid separation on that material, we found the Buffalo Creek Kaolin Member is about 100 times more enriched in the heavy rare-earth elements relative to concentrations in upper continental crust. Our work suggests a way to obtain heavy rare-earth elements from kaolin ore, which hasn’t been done before. This constitutes a new resource for the rare-earth elements, which we are getting all from China.

—Dr. W. Crawford Elliott, senior author of the study and associate professor in the Department of Geosciences at Georgia State

Resources

  • W. Crawford Elliott, Daniel J. Gardner, Prakash Malla, Ed Riley (2018) “A New Look At The Occurrences Of The Rare-Earth Elements In The Georgia Kaolins” Clays and Clay Minerals 66 (3): 245-260 doi: 10.1346/CCMN.2018.064096

Comments

Engineer-Poet

How interesting!  I've long seen it written that the "rare" earths aren't actually rare, just hard to separate.  Here it appears there has been some pre-separated stuff literally right under our noses, waiting for us to find it.  (Kind of like uranium and thorium, the latter of which is also associated with rare earths.)

Let's hope we can make good use of it.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Your Information

(Name is required. Email address will not be displayed with the comment.)