As my name is ncclaymaker, I've some experience with clay, pottery and glazes and fluxes. The kiln that I use is a Scutt computer controlled device. That being said, I can control the timing and temperature with a high degree of accuracy.
Gold has a melting point of 1064 degrees Centigrade (1947 F), fugitive or vapor temp at 2600C (4712 F)
Iron has a melting point of 1538 degrees Centigrade (2806 F) n/a
Copper has a melting point of 1084 degrees Centigrade (1954 F) fugitive or vapor temp at 2595 C (4703 F)
Lead has a melting point of 328 degrees centigrade (622F) fugitive or vapor temp at 1750 C (3182 F)
If I were to "refine" out the gold, it would be with a small amount of copper included as an alloy. I would contain the concentrates in a crucible or vessel and melt the copper and gold together. Heat would cause Galena PbS or Iron Pyrites FeS2 to disassociate the sulphur from the iron or lead as a fugitive gas/vapor, leaving iron or lead, pour off the lead. Canter off the gold/copper alloy, dump the iron residue. Now would be a good time to sell the gold as is.