Patent ID: 11920250
Assignee: THE TEXAS A&M UNIVERSITY SYSTEM
Field: Surface technology, coating (Chemistry)
Classification: CPC C | IPC C

Claim 9:
10. A process for recovering a rare-earth element of interest from a natural salt-containing water, comprising:
in an electrodialysis metathesis system comprising at least one electrodialysis quad of a feed compartment to receive the natural salt-containing water, a substitution solution compartment containing a substitution salt solution, a first concentrated compartment, and a second concentrated compartment, each of said compartments in fluid communication via alternating cation- and anion-exchange membranes:
feeding the natural salt-containing water into the feed compartment;
applying an electric field across the electrodialysis metathesis system to initiate an exchange of cations and anions in the natural salt-containing water with cations and anions in the substitution salt solution via a metathesis reaction;

concentrating the substitution salt solution cations and the natural salt-containing water anions in the first concentrated compartment and the salt-containing water REE cations and other cations and the substitution salt solution anions in the second concentrated compartment via electrodialysis metathesis;
combining the cations and anions in the first concentrated compartment with the cations and anions in the second concentrated compartment as a combined concentrate;
adjusting pH of the combined concentrate to precipitate the rare-earth element of interest; and
recovering the rare earth element from the combined concentrate.