GRAPHITE

Natural graphite can be divided into three classes:

Disseminated flake – Flake graphite is a lamellar form found in metamorphic rocks, such as marble, gneiss, and schist. Each flake is separate, having crystallized as such in the rock

Crystalline vein (fibrous or columnar) – Crystalline vein graphite (also called lump or high crystalline graphite) is found in well-defined veins or pocket accumulations along intrusive contacts of pegmatites with limestones.

Amorphous Graphite – Amorphous graphite is commonly found as minute, microcrystalline particles fairly uniformly distributed in weakly metamorphosed rocks, such as slates, or in beds consisting almost entirely of graphite. They are usually metamorphosed coal seams with as much as 80% to 85% graphitic carbon. The graphite content of amorphous graphite deposits is dependent on the amount of carbon present in the original sediments. Certain amorphous graphite depositsundoubtedly were formed by contact (thermal) metamorphism, while others are probably the result ofdynamic (regional) metamorphism.

Graphite has been marketed as graphite, plumbago, or black lead. Industrial usage of such terms tends to be confusing to one not immersed in the industry. For example, the two main commercial categories of natural graphite are crystalline and amorphous; but all graphite is really crystalline and the commercial distinction is actually one of crystal size. Thus the term amorphous, although widely used, is a misnomer.

Important properties of Graphite:

• Melting point:It melts at approximately 3,550°C at a triple point under 88 kg/cm². It sublimes between 3,300°C and 3,500°C at 1.033 kg/cm². At 3,726°C, a second triple point occurs at approximately 100,000 atmospheres. Thermal oxidation in the presence of oxygen begins at 300°C, and the rate increases with temperature.
• Lubricity:Graphite is used in lubricants and brake linings because of its lubricity (slipperiness)
• Reactivity:Graphite is used in refractories because it is a good heat conductor while keeping its shape at high temperatures and does not react with molten metals.
• Electric (Thermal) Conductivity: Graphite is an excellent conductor of heat and electricity.
• Density: The specific gravity of graphite is 2.266 g/cc (crystal density)

We offer various grades of Graphite for industries such as Foundries, Refractories, Coatings etc., For further details on grades available and our offers please contact us.