Gold Refining Buying Smelting and Assaying Refinery ...
Precious metal scrap such as placer gold, dental gold scrap and gold metal foil is weighed and then smelted. As the gold scrap liquefies in the furnace, borax and soda ash are mixed in to separate the pure gold from other precious and nonprecious metals. A sample is removed for assaying, which is the process of measuring the gold content.