Rare Earth Recovery

Rare Earth Elements, or REEs, are a group of 17 trace metals that play important roles in the electronics we rely on daily. Their properties are so unique, they’re not replaceable. But their current supply is almost completely controlled by China, which creates shortages and security challenges. So, researchers are looking for domestic sources—and have found a surprising one: coal ash. When coal is burned at a power plant, it’s reduced to gases and about 10 percent of its weight in ash. In that ash, the trace metals from the coal become concentrated. Scientists from the Bureau of Economic Geology first recognized that coal ash could be a source for REEs. When they surveyed the ash produced by U.S. coal plants since 1950, they found 35 million tons that could be available for REE recovery. It’s currently stored in landfills and retaining ponds, mostly near the power plants. There are different concentrations of REEs in the ash. Eastern coal has the highest concentration, and Western coal the lowest—but western coal’s simpler molecular structure could allow more REEs to be recovered. The next step is to set up pilot projects to test the process, its energy requirements and environmental impacts. The preliminary studies look promising, offering a chance to build a domestic industry in Rare Earth Elements, while building better long-term storage for the coal ash. A technology win-win!