Sponsor: US Department of Energy

Abstract: The primary objective of this project is to complete the development and validation of novel processes for the recovery of carbonaceous materials and rare earth elements (REEs) from coal waste. In prior work, we have developed the hydrophobic-hydrophilic separation (HHS) process, which can selectively collect ultra-fine particles from an aqueous phase while producing dry products. The process has been successfully applied to fine coal wastes less than 44 microns, and the high-purity products can be utilized as feedstocks for various high-value carbon products, such as graphene, carbon foam, and synthetic graphite. The proposed work seeks to modify the HHS process by utilizing the Two-Liquid Flotation (TLF) concept. The resulting modifications will extend the range of particle sizes that can be upgraded using the HHS process, while also providing a smaller footprint, lower capital and operating costs, and higher throughput. Moreover, reject streams from the TLF process can be further processed to recover REEs and other critical minerals, thus promoting more sustainable waste management practices. When fully developed, the new technology will provide an economical method of transforming legacy coal mining waste materials to valuable resources that can be used to manufacture valuable materials and attract significant private investment. The end goal of the 12-month effort is to successfully demonstrate the new concept in a continuous process development unit (PDU) at a TRL of 5, which is an essential step toward commercialization.