Question: what are the physical methods used to refine gold?
Answer: Cupellation. The gold is placed into a pot and heated. ... 
Inquartation. The impure gold is smelted and grained to improve the surface area of the alloy. ... 
Miller Chlorination Process. In the Miller process, gold is refined by chlorine. ... 
Wohlwill Electrolytic Process. ... 
Aqua Regia Process.