Gold Melting Process
Materials & Equipment
Borax
Ceramic crucible
AuCl3
Gas Oxy acetyleneBlowtorch
PPE
Procedure• Prepare all the materials and equipment before hand.
• Pre heat the ceramic crucible from room temperature to
working temperature of ~ 1300oC slowly, so as not to crack the crucible due to thermal shock
• Sprinkle borax to the crucible just enough to cover the ceramic and melt it.
• Put the gold brown (AuCl3)powder to the crucible
• Heat up the brown powder below the melting temperature for 30 minutes, in order to oxidize the metallic contaminants
• Melt the brown powder by Oxy acetylene torch directly
• Melt until gold liquid is in circular-shaped• Pour the melt to the mold
• Let it cool down and remove from the mold• If there is flux material in the gold, remove it by soaking
in hot 50% sulfuric acid
• Wash with water and dry
Flux
• Weigh and record the weight
• Melt until gold liquid is circular-shaped• Pour the melt to the mold