I was a process engineer in an aluminum plant. While I didn't directly work in remelt, this is correct as I understand it.

20:1 is the net energy usage for new aluminum smelting:recycling.

Recycle your metals please.

Yeah, contaminants aren't a big deal with metal recycling.

I’m not saying we shouldn’t recycle, we of course should. But most local recycling plants don’t have that capability.

And the biggest problem are plastics - glass and metal materials are much more forgiving.

Raw materials is not what we’re talking about here. Local recycling plants are not processing raw materials - that’s a completely different process. They are very limited systems designed to process consumer materials.

Metallurgy isn't my field, but here's an educated guess...

There are different kinds of contaminants. In raw ore you largely have silicate rock and metals. In recycled material you have relatively pure metal (alloys), and a large variety of volatiles.

Now with ore you can grind it all into sand, sift it, and smelt all the heavy grains. The rock should mostly just separate from the metal, these are just phase changes. But with recycling, those volatiles are going to burn and some are going to react with the metals, changing the chemical makeup. And with ore, you basically know what minerals you're working with. With recycled materials, it's anyone's guess. Does this can contain some food residue? Or an oil? Perhaps chemical cleaning agents? Is another plastic container stuffed inside?

There's a lot of variables with recycled materials, I imagine it's hard to predict how some of those variables react.

I try and do my part.

Then clearly we're resisting "natural" progression, whatever that means. It's definitely against the direction for economic growth, and that runs the world. Line go up.