How I Learned to Stop Worrying and Love Molten Salt

I was thinking the other day about water purification out on the ocean. There's an old evaporation method that would leave behind lots of salt. In Permaculture anytime you have a supply or surplus of something you consider it as a resource and try to find way to employ it. So what use O Salt?

BTW, this is exactly the reason why, when my friend first told me about the GGP, I immediately exclaimed, "Wow! A huge pile of free resources just laying there for the taking in Int'l Waters!? I'm moving there!" I'm not insane, nor brilliant. I'm a Permie.

So salt, just by itself is pretty amazing stuff. Not only is it delicious, despite being made from two extremely iffy substances, chlorine and sodium, but it has useful industrial properties as well.

But where it gets really interesting is when you heat it up. When you, in fact, liquefy it.

Molten salt, it turns out, is an extremely useful liquid. I recall hearing about solar power plants in the desert that use mirrors to melt salt, which is then pumped to a storage vat or heat exchanger.

It melts at 801°C (1473°F) and becomes like water. Red hot water, but a gentle liquid that's stable at normal atmospheric pressures, nontoxic, nonflammable, and relatively easy to work with.

It's a great way to store and move heat, because it holds so much of it. But then I found "What is Molten Salt & Its Technology?" if you read one web page on molten salt this year, read that one.

Read especially the part about Molten Salt Oxidation (MSO) which is basically the funnest way I've ever heard of to do fun things with trash.

Here's the deal: You get a great big vat of salt, you beam it with concentrated sunlight or grind it in a gigantic mortar, until it gets all red hot and nice and soupy.

Then you throw in A) some trash and B) a pinch of oxygen.

The trash oxidizes, burns, but without flames, because it's "underwater" only the water is molten salt. Am I going too fast here?

The trash and the oxygen burn together in the salt bath. Liquid fire.

All the nasty molecules are broken down into simple harmless parts. Whatever trace amounts of various elements in the trash either escape as gas, fall to the bottom as "ash", or remain disolved in the soup. These all have to be collected, scrubbed from the fumes, rinsed from the salt and raked from the bottom of your vat.

If we wind up using MSO, finding ways to ensure that all the elements in the soup are accounted for, either sequestered in harmless molecular form or reused in safe industrial processes, will be one of the true challenges in this adventure. (Caring for the sea life we are sure to find is another one!)

But most of the plastic we are going to recycle is carbon and hydrogen, and these react beautifully to being oxidized in salt. All the carbon oxygen and hydrogen eventually leave the soup together as something called synthesis gas which is a mixture of CO and H₂ (carbon monoxide and hydrogen).

It's called synthesis gas because you can apparently synthesize most organic chemicals from it. You can also burn it as a fuel, or you can react the CO with H₂O to make carbon dioxide and more hydrogen.

We can feed the CO₂ to our plants, and use the hydrogen for energy and buoyancy.

We can convert the trash in the Great Pacific Garbage Patch directly into air-for-plants and hydrogen gas!