(633f) Economic Extraction, Recovery and Upgrading of Rare Earth Elements from Coal-Based Resources

Coal-based resources such as waste rock near the edges of coal seams often contain significant quantities of rare earth elements. These resources often end up on waste piles. In many locations, the waste piles become acidic after long periods of time, and the associated acidic environment causes a slow release of metals, including some rare earth elements that are lost in waste treatment facilities. These resources can be recovered economically through appropriate processing of the coal feed material to produce a waste that is concentrated in rare earth elements that can be extracted using heap leaching with solutions from engineered biooxidation of pyrite naturally found with the coal resource, and subsequently recovered through solvent extraction and precipitation. In order to address this opportunity for low cost REE extraction and recovery, the objective of this study and the related DOE-funded project is to demonstrate and improve methods to economically extract, recover, and upgrade the rare earth element (REE) contents from vast coal-based resources using integrated modeling, targeted coal preparation, biooxidation, solution conditioning, heap leaching, solvent extraction, and precipitation technologies to produce rare earth bearing products in an environmentally friendly way. Utilization of these integrated technologies will enable coal producers to utilize untapped resources to produce revenue and extend resource life while simultaneously reducing future environmental issues and costs as they supply critical domestic REEs. Although this approach will be designed for coal ore processing facilities, it will be easily adapted in the future to the recovery of REEs and mitigation of acid rock drainage from coal tailings. Thus, this technology will enable recovery of an underutilized resource in an environmentally friendly way. Initial results from this study will be presented and discussed.