Answer to world’s garbage problems? Unlikely, but…

I’ve been thinking about this for a while… it’s a method that could be used, in combination with other processes, to recycle anything - even nuclear waste. Of course, it’s not easy, or people would be using it already.

Here is an outline of the method:

1. Pick through the garbage for useful things first… a lot of things are thrown away that still have some kind of use. Certain things, like scrap aluminum, can probably be recycled more efficiently using specific aluminum recovery methods.
2. Divide the garbage into very large chunks, and try to sort the chunks roughly by weight and/or density. This will save some time and energy later.
3. Dump one chunk of garbage into a giant, sealed arc furnace (or similar device) and melt it at some insanely high temperature, such as 5000°C. All the molecules of the garbage will break apart, leaving only the atomic elements, and those elements will reach their melting points and become liquids. The furnace has to be sealed because some elements will become gases, and these gases must be siphoned off, separated, and recycled separately.
4. Pour the molten garbage into a centrifuge, and spin the centrifuge at a very high RPM. Because the garbage is now a liquid, it will flow freely. The heavier elements, such as uranium and lead, will move to the edge of the centrifuge, while lighter elements, such as lithium, will move closer to the middle of the centrifuge. The crude diagram below illustrates this. Red is the heaviest element, and yellow is the lightest element.
5. While the centrifuge is still spinning, cool down the contents of the centrifuge. I suppose you could try and recycle the thermal energy by putting it back into the furnace using a heat pump.
6. When the centrifuge is cold, stop it. Cut and remove blocks of material from the centrifuge. Sort these by density and test their purity. The density can be used to guess what elements the blocks are made of, and sort the blocks into similar piles. If the blocks are of sufficient purity, they are fully recycled and can be used for new products. If they are impure, they can be melted and spun again (jump back to step 2) until pure blocks are obtained. Similar blocks are grouped together in each iteration.
7. Once pure blocks of material are obtained, they can be refined further using processes specific to that material before being used in new products.

Drawbacks of this method:

• You’d need a 5000 degree furnace.
• You’d need a centrifuge capable of withstanding 5000 degrees.
• It would be dangerous to try to recycle certain materials, like explosives or acids. You wouldn’t want a dangerous chemical reaction to occur inside the furnace. Additionally, some materials could react with and damage the furnace walls…
• If for example you recovered nuclear material using this method, some of it would become a gas, some of it would stick to the furnace over time, and some of it could become embedded in other materials that you are trying to recover. It’s also possible that a nuclear reaction could occur in either the furnace or centrifuge…
• You would need to capture all of the gases that were created in the melting process; it would be really dangerous not to.

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