Why can’t we recycle plastic in the same way we do for metal? Melt it and remold it?
In: Technology
First, let’s limit this to thermoplastics. That’s a type of plastic that can be melted. HDPE, ABS, PLA, PET, nylon, polyester, polycarbonate, acrylic are some types you’ve probably heard of.
A big part of the reason that metal is very forgiving when recycled is that the extremely high heat burns off contaminates, and most of what’s left turns into slag that’s easily skimmed off. It’s also not a huge deal if a little bit of other metals/alloys are in the mix. Sure, that changes the alloy a little, but that’s easily and quickly tested, and can be addressed. Metals can be recycled over and over, and aluminum is often described as being indefinitely 100% recyclable, and nearly 75% of all aluminum ever made is still in use in either its original or recycled form.
Plastic is tough to recycle because a miniscule amount of contaminate, including the wrong type of plastic, can irreparably ruin the entire batch.
It’s also tough to sort plastic. Bigger rigid items are much easier because automated systems can identify, sort and clean them. Shreds and sheets of plastic are basically impossible unless it comes from a manufacturing facility that already presorts it. Yeah, they might be technically recyclable, but identifying, sorting and cleaning it from a mixed batch of recyclables is incredibly expensive. Like how do sort a “polyester” t-shirt? The fabric may be polyester, with cotton or nylon thread, a nylon tag, and possibly some screen printing or embroidery.
Another problem is that the quality of plastic gets worse every time it’s recycled, which limits its applications.
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