Raw materials come from the ground. By your standards of “contamination” aren’t raw materials much more contaminated?
A lot of work goes into refining glass, aluminum, steel, copper etc. A lot of impurities have to be removed to make those materials for the first time.
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.
We’re talking about whether recycling is feasible.
Whether or not it is feasible is decided by how hard it is to do compared to just making new materials.
Your comment seemed to be saying the contaminates in recycling make them harder to recycle back to their raw materials (compared to making new raw 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.
Raw materials come from the ground. By your standards of “contamination” aren’t raw materials much more contaminated?
A lot of work goes into refining glass, aluminum, steel, copper etc. A lot of impurities have to be removed to make those materials for the first time.
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.
Why not make better recycling plants?
Couldn’t agree more
We’re talking about whether recycling is feasible.
Whether or not it is feasible is decided by how hard it is to do compared to just making new materials.
Your comment seemed to be saying the contaminates in recycling make them harder to recycle back to their raw materials (compared to making new raw 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.
For metals, it’s pretty trivial to remove slag (contaminants) from the metal. Basically everything floats to the top and you can just scrape it off.