Smelting is a common practice used to refine a metal from an unconcentrated source, such as an ore or prefabricated source. Smelting gold refines the metal to a pure 99.9% state. This process is accomplished by melting the gold with a specially formulated flux, designed to oxidise the impurities from the melted product. Smelting gold is done with cast iron or graphite, since their melting points are substantially higher than that of gold.
Don all of your safety equipment, including your safety goggles, fireproof apron, and fireproof gloves. Safety equipment is crucial when smelting, as the metals you will be working with can severely burn you.
Combine the gold and flux in your crucible. You will need to add around 1 to 2 parts of flux for each part of gold concentrate.
Place the crucible into the cool furnace. Turn on the furnace and let it warm up to between 260 to 316 degrees Celsius.
Raise the temperature of the furnace to 1093 degrees Celsius, and hold it there for about 30 minutes.
Use your tongs to remove the crucible and pour it into the mould. Make sure you warm up your mould and tongs to prevent thermal shock. Set your mould on a warm surface, and let the gold cool.