Graphite is a carbonaceous element mineral crystals, crystal lattice of its hexagonal layered structure, shown in Figure 1 - 1. The distance between each grid is 3.40, and the spacing of carbon atoms in the same network layer is 1 42A. Is the six party system, layered with complete cleavage. The cleavage surface is mainly composed by molecular bonding, weak on the molecular attraction, so the natural floatability is very good.
Graphite soft, dark gray, greasy feeling, can pollute paper. Hardness of 1 to 2, along the vertical direction along with the increase of impurities can be increased from 3 to 5. Specific gravity is 1.9 to 2.3. Under the condition of isolated oxygen, its melting point is above 3000, and it is one of the most heat resistant minerals.
Pure graphite in nature is not, which often contains A1203, Fe0, Si02, CaO, P2O5, Cu0 and other impurities. These impurities often appear in the form of quartz, pyrite, carbonate and other minerals. In addition, there are water, asphalt, CO2, H2, N2, CH4 and other gas parts. Therefore, the analysis of graphite, in addition to the determination of fixed carbon content, it must also determine the content of volatile and ash content.