You can remove the most common metals found in gold ore (copper, zinc and lead) using elements that bond with oxygen at lower temperatures than gold. This oxidation process will make copper oxide, zinc oxide and lead oxide all of which are less dense than pure gold and will float to the top of your crucible allowing the slag to be sloughed off.
2012 11 12 Microwave Heating Applications in Mineral Processing 81 which was shock cooled through water quenching, showed no difference in the product size distribution of the material after milling. Comparisons of results obtained from the same heat treatments after comminution by slow crushing, however, indicate that quenching the
First of all, you must have gold or silver in your concentrates to begin with and the more of it the better. The microwave gold smelting kiln is a tool for smelting only. It does not separate out the precious metals that are in your concentrates. You still need to have your end product called "buttons" assayed to determine its purity and content.