Formerly u/CanadaPlus101 on Reddit.

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Joined 2 years ago
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Cake day: June 12th, 2023

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  • Nope, metals are elements as opposed to molecule compounds and literally can be melted and cast forever. They say most of the gold ever mined is still in use today, so your modern ring might have bits of a ring melted down in ancient Egypt in it. Glass is like this too. Paper is more like plastic, albeit somewhat biodegradable when it eventually has to be thrown out.

    In practice, there’s still a limit for many metals because they will get contaminated. Copper building up in scrap steel is a problem IIRC. It’s not a big issue with aluminum, though, unless you’re doing something like building an airplane where you need super high purity. Cans are almost all recycled into more cans.

    There are ways to purify a metal melt, but they can be expensive and usually produce waste slag. I’ve never heard of glass being purified; it’s probably too cheap to not just make more of, since it’s derived from really common minerals.


  • Not very well. Those long molecules break down into shorter segments every time they’re recycled, which makes for an inferior and eventually useless product. Some plastics are also thermoset and can’t ever be melted again, and some are just hard to recycle for other reasons and get picked out and landfilled. The whole idea of plastics recycling is basically greenwashing on a massive scale; the industry put a lot of money into promoting it to avoid scrutiny.

    That being said, they’re also permanent in the good way. Plastics don’t biodegrade or erode. If you bury a plastic pipe in the ground, it may well still be there and intact in a million years. Anything natural will rot long before that, common metals will corrode, and concrete usually has metal rebar inside that pulls it apart as it corrodes. Plastic is also lightweight, which ceramics (stone-like materials) and metals are not, while still being strong under tension like metals.

    Sunlight does slowly break down many plastics, but only into ever-smaller particles, which is where the microplastics in OP come from.