What value does mixed metal have when melted in a foundry?

Which are you talking recycled in bound or junk on the top of the crucible or bucket in the foundry.

@Tropical_Willie Random scraps and junk melted.

Slag has little or no metal in it. Mostly glass like products and metal oxides. I’ve got several pieces from a mid-1800’s to 1920’s foundry in Vermont on Furnace Creek.

Back in my time we called it pot metal, and during the 50s & 60s the British in paticular utilized it for non critical parts in all sorts of machinery including cars and motorcycles.

The slag @RedDeerGuy1 is talking about is the junk on top of the bucket.
Pot metal is a lead copper mixture for plumbing; the cheap metal you are talking about @stanleybmanly is “white metal” a zinc alloy for cheap castings (it is fragile and breaks easily when hit).

Thanks T W. I never heard that before. I always thought that the only thing required of pot metal was a low melting point.

When metal scrap is recycled, and it is all mixed together it is “mixed metal.” It still has to be separated before melting. The basic separation method is electromagnetic, to get the steel out. Metals melt at different temperatures, so while the metal is melting, the different metals are taken out of the smelting process when such temperatures occur. Recycled steel of different types are melted together, and low tensile strength quality (not high tensile strength) products are made, like roof/gutter flashings, rebar, etc.