You might be interested in an article that appeared in AJM magazine
in October, 2003 by Dr. Christopher Corti of World Gold Council. In
the article, he discusses in detail six methods of refining precious
metals, ranging from ancient to modern.
From reading the article, I rather doubt this is something that you
really want to do at home – all the methods discussed involve
potentially hazardous substances and/or processes. But I can’t think
of a better way of answering your questions (and probably some you
haven’t thought of) than reading this article.
To order a copy of the article, visit the AJM Web site at
www.ajm-magazine.com. MJSA members can get free copies, while others
pay a processing fee, I think $5 per article.
Phone: (508) 339-7366
Fax: (928) 563-8255