Question

Why are the logs of green wood used in poling for the refining of certain metals?

Answer 1

1. Logs of green wood are used in poling because they release hydrocarbon gases when stirred in molten metal.
2. These hydrocarbon gases reduce oxide impurities present in the crude metal.
3. The oxide impurities are either removed as gases or form a scum on the surface.
4. This scum is skimmed off, leaving behind pure metal.
5. Poling is especially used when crude metal contains oxide impurities, such as in blister copper refining.

This method effectively removes oxides and purifies the metal.