The scarcity of Rare Earth Element (REE) supply may soon be provided with a solution as researchers from the Idaho National Laboratory and Rutgers University, are on the verge of perfecting a method of extracting large supplies from mining wastes. Currently, China accounts for 90% of global REE production, practically giving the country a global exclusivity over its supply.
INL Researchers Zeroes in on Mining Wastes as Abundant Sources of REE Supply
Phosphogypsum (PG), a waste product, which the Idaho researchers have previously determined as containing rare earth elements, is said to exist in tons of mining wastes in Idaho, and in other storage sites throughout the country, particularly in Florida.
PG occurs as mining wastes resulting from the production of phosphoric acid out of phosphate rocks. The INL researchers estimate that the process yields about 100,000 tons of PG each year, nearly as much as the 126,000 tons annually produced worldwide.
Previously, they conducted corollary researchers about various solutions deemed usable in extracting the six rare earth elements: cerium, europium, neodymium, samarium, ytterbium and yttrium. One such solution was a mixture of chemicals produced by Gluconobacter oxydans, which they then used in recovering REEs from spent liquid cracking catalyst, a substance widely used in refining petroleum and other sources of REEs.
Proving Chemicals from Gluconobacter as Efficient Solutions for REE Extraction in PGs
Gluconobacter is a type of bacterium that prefers sugar-rich substances, commonly found in the environment usually in rotting fruits. The bacterium therefore is readily, widely and easily accessible.
In its use in extracting REEs, the gluconobacter produces a chemical solution of organic acids that dissolve the REEs from the material through a process called “bioleaching.” Once the rare elements have been pulled out, they form a substance from which the extracted REEs would be precipitated and thereafter, purified for industrial use.
This recent study proved that as extraction agents, the chemicals produced by Gluconobacter outperformed other acids like gluconic and phosphoric acid.
Research scientists David Reed and Yoshiko Fujita of the Biological and Chemical Processing Department at the INL Lab, explained that the significance of the result of this latest chemical studies, is that Gluconobacter has been proven efficient in recovering REEs from PG-producing industrial wastes. That is considering there is an abundant supply of PG from mining wastes, in measures enough to alleviate the global shortage in the supply of Rare Earth Elements.