Rare earth elements (REEs), such as lanthanides, yttrium, and scandium, are critical components in numerous advanced technologies, including electronics, energy storage systems, and medicine. Currently, the majority of REEs are sourced from a limited number of mining operations, which poses substantial risks to geopolitical tensions, supply chain disruptions, and environmental concerns. Moreover, REE mining operations require high energy consumption, produce significant greenhouse gas emissions, and negatively impact local ecosystems. For the sustainable development of advanced technology, it is crucial to develop alternative methods of REE extraction. Notably, coal combustion for energy production generates large quantities of coal fly ash, a byproduct that is often treated as waste and disposed of in landfills. This fly ash contains REE concentrations up to 1500 ppm, presenting a largely untapped resource that could alleviate the dependency on conventional mining.
Researchers at The University of Texas at Austin have invented a novel spatiochemical characterization method for optimizing rare earth metal extraction from coal fly ash. This method was demonstrated in aluminosilicate matrices of fly ash samples (collected from Powder River Basin feed coal), revealing the influence of ash’s microscale physical properties on REE recovery. For example, REE recovery in dense aluminosilicates is controlled by progressive leaching. Alternatively, intraparticle pore fluid flow controls REE recovery in porous aluminosilicates. Impressively, this technology utilizes both processes to optimize REE recovery in any ash waste.
Publication: “From Ashes to Riches: Microscale Phenomena Controlling Rare Earths Recovery from Coal Fly Ash” (https://doi.org/10.1021/acs.est.2c04201)
Electronics manufacturing; lithium-ion battery manufacturing; coal ash recycling