Types of Graphite

Types of Graphite

The mineral graphite is soft, silvery-grey to black in colour, has a light metallic sheen and is very flexible but not elastic.graphite electrode Its unique combination of properties, which combine both metal and non-metal, make it an important raw material.graphite electrode It is used extensively in industrial applications, including high-temperature lubricants and brushes for electric motors, friction materials and batteries.graphite electrode It is the only natural crystalline form of carbon, although it may occur as amorphous carbon in beds of metamorphic rocks such as coal or slate.

Graphite is naturally very soft and is therefore an excellent dry lubricant.graphite electrode It is also a very good conductor of heat and electricity.graphite electrode The reason for its greasy feel is that, on an atomic level, it has a sheet-like structure, with carbon atoms loosely bonded to one another by weak surface attractions called Van der Waals forces (these are the same attractive forces that allow geckos to climb smooth surfaces with their padded feet).graphite electrode

Flake graphite is a type of mineral graphite which forms in veins and disseminations in metamorphic rocks.graphite electrode This variety of graphite is generally higher in purity than vein graphite, with some reaching 99.graphite electrode 5% carbon in the “as found” state.graphite electrode Flake graphite has a flake like macro-morphology and, when viewed using polarised light microscopy, it typically shows elongated needle-like particles with an intrinsic flake morphology.

Graphitization is the process of turning amorphous carbon into graphite by subjecting it to elevated temperatures in the presence of a volatile coke.graphite electrode During graphitization the amorphous carbon reorganises itself into a sheet-like structure with a network of pore spaces that gives it its lubricity and electrical conductivity.graphite electrode During the Graphitization process most impurities are volatile and thus escape, leaving behind the pure graphitic material.graphite electrode

Vein graphite forms as a result of fluid-to-solid deposition from a fluid that has travelled through a metamorphic rock, depositing carbon from the surrounding country rock matrix.graphite electrode This variety of graphite tends to be softer than other types of graphite and it has an inherent “needle-like” morphology when observed in fracture fillings under polarised light microscopy.graphite electrode Unlike other varieties of graphite, vein graphite cannot be mechanically/chemically processed or "upgraded" to reach the required purity for industrial applications.graphite electrode

The majority of the world’s graphite is produced as a by-product from the manufacture of batteries and electrodes.graphite electrode Whenever an electrode is manufactured or replaced, a sizeable piece of the old electrode remains.graphite electrode Coidan Graphite have developed an energy-efficient process to recover this material and convert it into Green Graphite. This process uses 99% less energy than producing new graphite electrodes from scratch, saving thousands of tonnes of waste material from landfill sites each year. The Green Graphite is then used in the production of advanced brake and clutch materials for the automotive industry.

Tags:graphite electrode