• bearboiblake@pawb.social
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    1 day ago

    oh wow, i didn’t realize that, i thought it was infinitely reusable just by melting and re-forming it. thank you really much for the explanation.

    what you wrote reminded me of silly putty, it’s really stretchy and elastic to start with, but if you play with it for a while, it starts to be less elastic and breaks apart.

    does metal also break down? i’m thinking about like aluminium cans that are used for soda and stuff like that

    • CanadaPlus@lemmy.sdf.org
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      1 day ago

      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.

      • Korhaka@sopuli.xyz
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        1 day ago

        My cast iron pan was made from recycled iron. And if I bought it a month later it would be in the batch that has a product recall because they also recycled some lead in it

        • CanadaPlus@lemmy.sdf.org
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          3 hours ago

          Yep, that’ll do it. If you have a pile of scrapped iron things, you have to think it wouldn’t be hard to miss something that has a lead battery or weight in it somewhere. Although, I have to wonder why they didn’t test that batch before it was sold, if it’s for cooking in.

          I seem to remember a story about a radiation source for probing gas wells getting into scrap and causing problems. They just look something like a metal cylinder, so would blend in easily with all the other oil and gas errata getting scrapped.

          • Korhaka@sopuli.xyz
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            51 minutes ago

            The contaminated batch has quite a wide date range too, so presumably people could have been using it for a while.

            Not sure how much would end up getting into the food though. Presumably low enough levels that it’s unlikely to be much harm but still higher than is ideal.

    • AnUnusualRelic@lemmy.world
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      1 day ago

      A lot of metals are fairly easy to recycle. For others, being alloys (basically a mix of various metals in varying quantities), it’s more tricky as you can’t always really get a pure product out of recycling very easily, so it limits the types of things you can do with them. But all in all it’s way better than with plastics.