Thermally-driven ion-exchange process for lithium recovery

A process for producing a solution enriched in at least one desirable ion (DI) from a feed solution containing DI and at least one undesirable ion (UI), the process comprising in a first phase of a cycle the steps of:

• (i) at a first temperature, flowing a solution comprising a reflux portion of a product enriched in said DI through a first zone comprising at least one bed of an ion-exchange material having a higher temperature-dependent selectivity for DI at said first temperature compared to at a second temperature different from said first temperature, and obtaining as the effluent from said first zone a product impoverished in said DI;
• (ii) at said second temperature, flowing a solution comprising a reflux portion of said DI-impoverished product from step (i) through a second zone comprising at least one bed of an ion-exchange material having a lower temperature-dependent selectivity for DI at said second temperature compared to at said first temperature, and obtaining as the effluent from said second zone said product enriched in said DI, wherein said DI comprises lithium ion, said UI comprises at least one other alkali metal ion, and said ion-exchange material comprises zeolite X.

A process for producing a solution enriched in at least one desirable ion (DI) from a feed solution containing DI and at least one undesirable ion (UI), the process comprising the steps of:

• (i) at a first temperature, flowing a solution comprising a reflux portion of a product enriched in said DI through a zone in a first flow direction, said zone comprising at least one bed of an ion-exchange material having a higher temperature-dependent selectivity for DI at said first temperature compared to at a second temperature different from said first temperature, and obtaining as the effluent from said zone a product impoverished in said DI;
• (ii) at said second temperature, flowing a solution comprising a reflux portion of said DI-impoverished product from step (i) through the zone in a second flow direction counterflow to said first direction, and obtaining as the effluent from said zone said product enriched in said DI;
• (iii) alternating said steps (i) and (ii) until at least one of the DI-enriched and DI-impoverished products contains an amount of DI or UI that meets at least one of predetermined purity and recovery specifications for said ion, wherein said DI includes lithium ion, said UI comprises at least one other alkali metal ion, and said ion-exchange material comprises zeolite X.