On Fri, 16 Oct 2015 06:59:00 -0700 (PDT), Tim
wrote:

Now metals are fed into huge shredders to fill export containers

https://m.youtube.com/watch?v=lXfitusZ9qY

That is mixed scrap, not near as valuable as sorted (clean) metals.
I assume that waste stream goes through magnetic separation at least
but you still need a way to separate aluminum and copper from the
plastic and glass.
That is easier done in a 3d world plant where labor cost, worker
safety and environmental concerns are not as important.