It depends on the contaminant. For example, if iron is polluted with carbon, carbon will dissolve and even react with iron to produce cementite. That’s how iron becomes steel.
And slag itself results in a metal loss. You can’t drain it off and not waste some of the material you’re recovering.
Basically there’s no such thing as 100% recovery of recycled material in an industrial setting. You can do it in the lab at astronomical costs, sure, but your local metalworks are not capable of that. But that doesn’t mean we should stop recycling.
Which literally means “anything other than aerospace engineering”. Aluminium and other metals are infinitely more recyclable than plastics, which as I’ve said before, degrade immediately to being barely usable.
Metals are also not 100% recyclable due to contamination. We just have plenty of use for low grade metal alloys.
Don’t most of the contaminants come out as slag? (IDK I’m not an industrial furnace)
It depends on the contaminant. For example, if iron is polluted with carbon, carbon will dissolve and even react with iron to produce cementite. That’s how iron becomes steel.
And slag itself results in a metal loss. You can’t drain it off and not waste some of the material you’re recovering.
Basically there’s no such thing as 100% recovery of recycled material in an industrial setting. You can do it in the lab at astronomical costs, sure, but your local metalworks are not capable of that. But that doesn’t mean we should stop recycling.
Which literally means “anything other than aerospace engineering”. Aluminium and other metals are infinitely more recyclable than plastics, which as I’ve said before, degrade immediately to being barely usable.