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iostream24

Seawater-> extract the lithium as a useful byproduct from desalination plants

https://www.science.org/content/article/seawater-could-provi...

https://cen.acs.org/materials/inorganic-chemistry/Can-seawat...

https://www.eurekalert.org/news-releases/699652

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Most desalination plants only concentrate the ocean salts a little.

The more you concentrate them, the more energy you need to put in to get any more water out. I think the only time this would make economic sense is if there are laws in place saying brine may not be returned to the ocean (for environmental reasons). In that case, it would make sense to concentrate it further with reverse osmosis, and then use multi-stage flash to further concentrate the brine.

After a few more steps, you could probably sell most of the resulting salts.

But if you’re already going to extract from seawater, you might as well take whatever head state you can get.

What is the process by which drinking water is extracted from seawater, and does that give you any savings at all with regards to a goal of extracting minerals?

You either boil it or force it through a semi-permiable membrane.

In both methods you get two products: one one side pure water, on the other water with a higher concentration of non-water things as waste, most often just dumped back into the ocean.

That waste stream is just a bit closer to the end product than taking from the sea directly.

The most common approach is reverse osmosis. This yields a waste brine that is up to 2x as concentrated as seawater. That's not negligible: it would reduce the cost of Li extraction that is proportional to mass flow by a factor of 2.

If it's unlawful to discharge brine to the ocean (that is, concentrated seawater), it'd still probably be more economical to just dilute it before discharge (they probably already do this).

If you need a desal plant, probably not a lot of water laying around to dilute your brine stream

Are they allowed to dilute it with wastewater?

Purifying wastewater is much cheaper than desalination.

Dilute it with seawater, I mean. Even it's not safe to discharge concentrated brine with, say, 10x the normal salt concentration, maybe seawater with 1.1x the usual concentration (or whatever it is) would be okay.

In some me places it is hard to discharge even 1.1x brine. In the future it might be necessary to concentrate it all the way to solid salt crystals and then truck them away.

Salt is just a depleted battery from the future

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