Use cases ·

Graphite types: properties of natural and synthetic graphites

Graphite is a very special mineral, as it is considered to be almost pure carbon. As we know, carbon can occur in the form of diamond, chaoite and lonsdaleite, but also as graphite.

Graphite types: properties of natural and synthetic graphites

Graphite is a very special mineral, as it is considered to be almost pure carbon. As we know, carbon can occur in the form of diamond, chaoite and lonsdaleite, but also as graphite. It should be noted that graphene is obtained from graphite.

Graphite has a compact texture and can feel greasy to the touch. It is black in color and has a metallic luster.

Its chemical properties make it a very useful material and conductor with different applications in daily life.

In order to understand the origin and use of graphite we must understand that there are two types of graphite in the world. Each one has different characteristics, origins and applications, which we will explain in this article.

Types of natural graphite

Natural graphite can be found abundantly in nature, in the form of metamorphic recrystallization of organic matter. When this occurs over layers of coal or petroleum-bearing rocks, deposits of this mineral arise.

Natural graphite consists mostly of up to 90% carbon, with some inorganic impurities that can be removed. However, its properties depend very much on the region in which it is mined. China, South Korea and India are the largest producers of this type of natural graphite. It can also be found in Brazil and Canada.

Natural graphites can be classified in three forms or presentations

  • Crystalline flake graphite: This presentation of graphite is composed of discrete particles in the form of flat plates with angular and irregular edges. Graphene is obtained from this type of graphite.
  • Crystalline vein graphite: This graphite accumulates crystallized in large pockets or deposits. Its carbon content is extremely high, up to 99%.
  • Amorphous crystalline graphite: It is formed from coal-rich sediments and has a crystalline structure.

Types of synthetic graphite

Synthetic graphite is created from a carbonization and graphitization process, which involves treating coal- or petroleum-derived materials at over 1,000°C. The properties of the grade of synthetic graphite are derived from factors such as the particle size of the mixture as well as its compaction by different processes, such as extrusion or molding.

There are two types of synthetic graphite

  • Isotropic graphite: It is generated by mixing coke and a binder at low temperature; these elements are melted, pressed, carbonized and graphitized.
  • Pyrolytic graphite: This type of graphite is obtained by depositing carbon at temperatures above 1,800°C or by graphitization heat treatment. Its properties make it possible to extract high quality graphene sheets.

Some uses of natural and synthetic graphite

  • Rechargeable and alkaline batteries.
  • Lubricants and polymers.
  • Additive in metallurgy.
  • Injection tubes.
  • Gaskets and packing.
  • Foundry electrodes.