Gold Smelting
A professional smelting gold machine in process. Once the ore is molten, chemicals – such as sodium nitrate, silica, lead oxide, sulphuric acid, and nitric acid – are added. Because gold is a noble metal and nonreactive, the impurities instead bond with the chemicals. This causes them to oxidise and rise to the surface, allowing the impurities to now be skimmed from the surface. Further ...