Graphite Crucible 1/2 / 3 / 4KG Metal Melting Gold Silver Scrap Casting Mould (3KG) AttentionOnly for ELECTRIC Furnace. Pure graphite crucible can NOT be heating by Carbon or Charcoal kiln. It will be oxidized and cracked; Pure graphite will start to oxidize at 752 F 400). The withstand temperatures can be 3200 F if you use Air Electric Furnace. SizeCapacity: 3KG gold; Height:105mm; Inner diameter:60mm; Top diameter:85mm; Bottom diameter:75mm PerformanceExcellent thermal stability for fast heating and cooling / Well corrosion resistance to strong acid and alkali / Good thermal conductivity properties which highly shorten the melting time and save energy / Great impact resistance performance to ensure the reliability of product quality. ApplicationMelting and casting metals such as Gold, Silver, Brass, Aluminum, Copper, Zinc, Plumbum, etc. Composition:99.9% Graphite. Ash content less than 0.1%. Excellentthermalconductivity and corrosion resistance. Better for Refining than Silicon Carbide Graphite Crucibles.