What are the classifications of graphite?
1. Natural graphite
The process characteristics of graphite are mainly determined by its crystalline form. Graphite minerals with different crystalline forms have different industrial values and uses. Industrially, natural graphite is divided into three categories according to different crystal forms.
2. Artificial graphite
In a broad sense, all graphite materials obtained by organic carbonization and then graphitization high temperature treatment can be called artificial graphite, such as carbon fiber, pyrolysis carbon, foam graphite, etc. In the narrow sense, artificial graphite usually refers to a block solid material prepared by batching, kneading, molding, carbonization, and graphitization by using carbonaceous raw materials with low impurity content as aggregates and coal pitch as binders. Such as graphite electrodes, isostatic graphite, etc. Artificial graphite can generally be divided into molding methods: vibration molding, extrusion molding, compression molding, and isostatic pressing.
3. Lump graphite
Bulk graphite is also called dense crystalline graphite. Such graphite crystals are clearly visible to the naked eye. The particle diameter is greater than 0.1 mm, the specific surface area is concentrated in the range of 0.1-1m2/g, the crystal arrangement is disorderly, and the structure is dense and massive. This kind of: graphite is characterized by a high grade, generally the carbon content is 60-65%, sometimes 80-98%, but its plasticity and smoothness are not as good as flake graphite.
4. Flake graphite
Graphite crystals are in the form of scales; they are transformed under high-intensity pressure and can be divided into large scales and fine scales. The characteristic of this type of graphite ore is that the grade is not high, generally between 2 to 3%, or 10 to 25%. It is one of the best floatable ore in nature, and high-grade graphite concentrate can be obtained through multiple grinding and selection. The floatability, lubricity, and plasticity of this type of graphite are superior to other types of graphite; therefore, it has the greatest industrial value.
5. Cryptocrystalline graphite
Cryptocrystalline graphite is also called microcrystalline graphite or earthy graphite. The crystal diameter of this kind of graphite is generally less than 1 micron, and the specific surface area is concentrated in the range of 1-5m2/g. It is an aggregate of microcrystalline graphite and can only be used under an electron microscope. See the crystal form. This type of graphite is characterized by its earthy surface, lack of luster, and its lubricity is slightly worse than flake graphite. Higher grade. Generally 60-85%. A few are as high as 90%. Generally used in the foundry industry.