Eforlife Graphite Crucible 1/2 / 3 / 4KG Metal Melting Gold Silver Scrap Casting Mould (4KG) SizeCapacity: 4KG gold; Height:130mm; Inner diameter:60mm; Top diameter:85mm; Bottom diameter:75mm 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. 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.