Store it in old oil tankers for future dispersal in polar oceans when salinity drops from glacial melting, potentially disrupting things like the Gulf Stream?

- ed "North Atlantic thermocline" is what I meant! I originally wrote "North Atlantic endocrine" before realising that was entirely wrong, and after wracking my brain went with 'gulf stream'. I need more tea.

I think I saw this somewhere else earlier, and one of the ideas listed was: don't use seawater, use other wastewater, like mining leachate, or similar. This gets rid of the water in it, making it more concentrated, and gives a useful product. The more concentrated heavy metal contaminated waste would then potentially be used as feed stock for extraction.

Or if you're using seawater, and have a convenient large area nearby, just make sea salt from it.

Sell it as some sort of high-end version of regular salt at Whole Foods?

It's simply left in the sea and washed away by the current. Presumably that results in a local salinification, which might limit the safe scale.

With some of it, we can make those fancy new sodium-sulfur batteries.

I doubt it, much less a problem than with desalination, volume wise.