Those are expensive and are avoided when possible. Brine ponds are cheap if you can use them. But with that said, yeah, evaporation ponds don't work especially well on the Gulf Coast.
The process for here, I was reading, would involve concentration of the lithium with resin absorbers (to separate it from other alkali elements, I imagine), followed by elution into water, reverse osmosis, and only then evaporation. This is called "DLE": Direct Lithium Extraction.
Yes, but that's among the most expensive ways of approaching the problem. In regions where it's feasible, evaporation approaches are far cheaper, which is why they're still the most widely used approach. In humid regions with a lot of precipitation like the gulf coast, though, you have to take more expensive and energy-intensive approaches to concentrate things.
A serious issue with pond evaporation is that it wastes all the waster. The DLE approach evaporates 98% less water. It's increasingly being used even in places like Chile where evaporation can be used.
