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