The crucible made of graphite material is called graphite crucible.It has a long history to use the graphite crucible.At first the graphite crucible consists of natural graphite (flake graphite and amorphous graphite) and clay,sand,using the pottery manufacturing process to produce.it used to melt metal(copper,iron,steel etc.)
The graphite has a high mechanical strength, refractoriness, Thermal conductivity,could withstand repeated smelting and Erosion of high temperature solution.with the development of modern industry, the development of metal casting in electric furnace makes the natural graphite limited.
Since the advent of artificial graphite by the end of nineteenth Century,the artificial graphite crucibles are widely used. High purity fine structure graphite,high strength graphite,glassy carbon material broaden the application range of graphite crucible.the graphite crucibles start to use for precious metals smelting, silver refining, uranium smelting, silicon manufacturing and chemical analysis.
Graphite crucible can be classified into natural graphite crucible,artificial graphite crucible,high purity graphite crucible and glassy carbon crucible according to its material classification.it also can be classified into steel melting,copper melting,gold melting and chemical analysis crucibles.
The service life of graphite crucible is determined by the material,quality,and the use methed.the graphite crucible is usually need high purity and high density in order to avoid the pollution to the melting metal.
The gold melting crucible need high purity and high density,the bulk density need to be >1.80g/cm3,and the ash need to be <50*10-6.the gold melting crucible is usually made of the high purity,high density and fine particle graphite material.
The graphite crucible used for uranium extraction is usually big type ones. Φ400mm*700mm and Φ500mm*800mm is widely used.
Graphite crucible is also widely used for chemical andlysis,it includes
(1) Graphite crucible for sampling before furnacing;
(2) Making standard sample.
(3) Glassy carbon crucible for chemical analysis.
(4) Oxygen analysis