This project demonstrated the technical viability of using tunable hydrothermal liquid (HTL) solutions to recover valuable minerals from a range of source materials. The effort focused upon rare earth elements (REE) and other minerals critical to the industrial security of the United States. This effort demonstrated, for the first time, that s, supercritical water (SCW) in particular, can:
• Extract critical and valuable minerals from a range of matrices ranging from rock ore to biomass.
• The process can be used to recover a wide range of minerals
• This novel extraction chemistry can be cheap, simple, and nontoxic/”green”
o The chemical extraction uses water, the cheapest industrial acid (sulfuric), and simple salts (i.e. sodium sulfate). However, other acids, salts, and additives could be used as appropriate.
This Laboratory Directed Research and Development (LDRD) project identified that the process is complex with many interacting factors, but the benefits are significant if the complexities can be resolved. Challenges remain in the development of this technology and are described in this report. However, the results are positive, and commercial partners have already expressed interest. In summary, a novel, green, inexpensive mineral extraction process has been developed and demonstrated in a small batch reactor system. The effort provided information for an invention disclosure, proposal to DOE, and will support future business development efforts.