In my city, plastic bottles are shredded and converted into filament for 3D printers: https://www.greenbatch.com/

Maybe it takes more energy because of the diversity of materials? If we used an order of magnitude less types of plastic than we currently do, it might become more economical because it wouldnt require as much mechanical labor to sort and process. Removing shipping from the equation seems like the removal of quite a bit of carbon.

When you melt plastic down, you get lower quality material than what you fed in. It's not a closed loop. Plus, the wide variety of available properties are what makes plastic so useful in the first place.

Source?

This is what the big kerfuffle is all about.

All we’ve been doing is paying the Chinese and Malaysians to feed our plastics to the dolphins for us.

Now they won’t take it, and people here get upset if you feed the animals, we’re realise the whole deception for what it is.

Edit to add sources:

https://www.nationalgeographic.com/environment/2019/03/whale...

https://www.theguardian.com/world/2019/may/29/malaysia-to-se...

Self evident that if it were economically & environmentally sound to recycle we wouldn’t be shipping it around the planet to do so.

Asian companies undercut all the domestic recyclers, putting them out of business. This is why you might not want to trust say Chinese companies with prices that are too good to be true (because they are probably cutting huge corners somewhere). The same thing happened with rare earths (very dirty to refine, but China didn’t really care about their environment giving them a huge price advantage that shut everyone in the developed world down).

Thomas Kinnaman was interviewed on Planet Money recently and mentioned roughly this conclusion based on his 2014 study. More details here: https://www.realclearscience.com/blog/2019/07/15/why_its_pro...

Plastic and Glass recycling can be borderline and it depends on the specific local implementation. Either way, the savings are never going to be massive and it is an open question if it is worth the effort. (Glass re-use is different)

Aluminum is completely different. Prices for aluminum recycling per ton is an order of magnitude higher than other recyclables.