What does "calx" mean in oxidation reduction reactions?

1 Answer

It is a term commonly used in reactions where you are roasting a metal in a place with excess oxygen (I did this in an Inorganic Chemistry lab in a hood).

Basically you can put a metal in a crucible on a wire mesh (or clay triangle, like in the diagram) on a ring clamp on a ring stand over a bunsen burner, and heat it until it forms a purer substance. Calx is the remaining ashy residue.

https://salve.digication.com/morgan.smith/Methods_equipment

You have to keep watch over it though, and if it goes for too long, the pure ore would be burned too and you'll just have soot.