How to Enhance the Purity of High Purity Graphite Powder
high purity graphite powder is a useful material used in industrial applications such as crucibles, lead pencils, electrodes, and lubricants. It is also used for foundry facings and linings, glass manufacture, conductive coatings and in the synthesis of single sheet graphene nanoflakes. It is a very stable, highly crystalline and strong material with thermal stability, excellent conductivity, self-lubrication, and good strength.
A method has been developed to improve the quality of graphite powders by introducing an effective, chemical-free and simple floatation technique to concentrate the ground mineral impurities on the surface of de-ionized water. This method does not require any froth forming or floatation aid chemicals and is more efficient than the complex purifying methods currently used in industry.
This method is especially useful for enhancing the purity of regenerated (synthetic) flake graphite because it eliminates the need for toxic acid or alkali treatments. It is also more cost-effective than the current production processes.
Regenerated flake graphite is produced from waste material skimmed off the molten iron feed to a basic oxygen furnace in steelmaking. The material consists of a mixture of natural flake graphite, lime-rich slag and some iron. Typically, this graphite is processed by hydraulic classification (which separates minerals by specific gravity: the lighter minerals settle nearly last), followed by leaching with hydrochloric acid to get a 70% graphite rough concentrate. This concentrate is then ground and pulverized to produce high purity graphite powder. Graphite powder has an excellent conductive properties because the valence electrons can move freely within its unique layered molecular structure.
