News List

News

Products

Elementary

Boride powder

Oxide powder

Sulfide powder

Hydride powder

Carbide powder

Silicide powder

Acetylacetone salt series

Myristate series

Rare Earth Chloride

Rare earth nitrate

Nitride powder

Telluride

Environmental material

3D printing materials

Company News

Natural graphite after deep processing to become artificial

2019-06-17
Is it natural graphite after deep processing to become artificial graphite? 
If artificial graphite is better than natural graphite, what is the value of natural graphite?
 
Graphite can be divided into natural graphite and artificial graphite, the structure of the two are similar, similar physical and chemical properties, but the use is a big difference.Among the many studies, some researchers did not notice the difference and called it graphite in general.This confusion of the two results in a lot of misleading, even decision-making errors, leading to a large waste of resources and economic losses.In this paper, the characteristics and differences of natural graphite and artificial graphite, as well as their important connections and application progress are discussed.
 


 
Classification and characteristics of graphite:
 
Natural graphite
Natural graphite is the formation of carbon-rich organic matter under the long-term action of high temperature and high pressure geological environment, and is the crystallization of nature.The technological characteristics of natural graphite mainly depend on its crystalline morphology.Minerals with different crystalline forms have different industrial values and USES.There are many kinds of natural graphite. According to the crystal morphology, natural graphite is divided into three categories: dense crystalline graphite, flake graphite and cryptocrystalline graphite.There are two major categories of flake graphite and cryptocrystalline graphite in China.
 
Artificial graphite
Synthetic graphite is similar to polycrystals in crystallography.There are many kinds of artificial graphite and different production techniques.Broadly speaking, all graphite materials obtained through carbonization of organic matter and graphitization at high temperature can be collectively referred to as artificial graphite, such as carbon (graphite) fiber, pyrolytic carbon (graphite), foam graphite and so on.Artificial graphite in narrow sense usually refers to low content of impurities of carbonaceous materials (petroleum coke and pitch coke, etc.), coal pitch as binder for the aggregate, after the ingredients, kneading, molding, carbonization (known as the roasting industry) and graphitization process of bulk solid materials, such as graphite electrode, such as hot isostatic pressing graphite.

 


 
The difference and connection between natural graphite and artificial graphite
In view of the above natural graphite as raw material is usually prepared from the narrow sense of artificial graphite, is only to analyze and discuss the difference and relationship between natural graphite and narrow sense of artificial graphite.
 
Crystal structure
Natural graphite: crystal development is more complete, the degree of graphitization of flake graphite is more than 98%, and the degree of graphitization of natural microcrystalline ink is usually less than 93%.
Artificial graphite: crystal development depends on raw materials and heat treatment temperature.Generally speaking, the higher the heat treatment temperature, the higher the degree of graphitization.Currently, the degree of graphitization of artificial graphite produced by industry is usually less than 90%.
 
Organizational structure
Natural flake graphite: it is a kind of single crystal with simple structure and only crystallographic defects (such as point defect, dislocation, stratification, etc.).Natural microcrystalline ink grains are small, grains are disorderly arranged and there are holes after impurity removal, macroscopic isotropy.
Artificial graphite: it can be regarded as a kind of multiphase material, including graphite phase transformed by carbonaceous particles such as petroleum coke or asphalt coke, graphite phase transformed by coal-asphalt binder coated around the particles, pores formed by particle accumulation or coal-asphalt binder after heat treatment, etc.
 


 
Physical morphology
Natural graphite: usually in powder form, can be used alone, but is usually used in combination with other materials.
Artificial graphite: form more, have powder, also have fiber and block, and the narrow sense of artificial graphite is usually block, need to be processed into a certain shape.
 
Physical and chemical properties
In terms of physical and chemical properties, natural graphite and artificial graphite have both similarities and differences in properties.For example, natural graphite and artificial graphite are good conductors of heat and electricity, but for the same purity and particle size of graphite powder, natural flake graphite heat transfer performance and conductivity performance is the best, natural microcrystalline ink followed, artificial graphite is the lowest.Graphite has better lubricity and certain plasticity, natural flake graphite crystal development is more complete, friction coefficient is small, the best lubricity, the highest plasticity, and dense crystalline graphite and cryptocrystalline graphite followed, artificial graphite is worse.

 


 
Application fields of natural graphite and artificial graphite
Graphite has many excellent properties, so it is widely used in metallurgical, mechanical, electrical, chemical, textile and national defense industries.The application fields of natural graphite and artificial graphite overlap and differ.
 
Metallurgical industry
In metallurgical industry, natural flake graphite can be used to produce refractory materials such as magnesium-carbon brick and aluminum-carbon brick due to its good oxidation resistance.Artificial graphite can be used as steel making electrode, but the electrode made of natural graphite is difficult to be used in the steel making furnace with harsh conditions.
 
Machinery industry
In the mechanical industry, graphite is commonly used as a wear-resisting and lubricating material.Natural flake graphite has good lubricity and is often used as lubricant additive.The equipment for conveying corrosive medium is widely used with piston rings, sealing rings and bearings made of artificial graphite, without adding lubricating oil when working.Natural graphite and polymer resin composites can also be used in the above fields, but the abrasion resistance is not as good as artificial graphite.
 
Chemical industry
Artificial graphite has the characteristics of corrosion resistance, good thermal conductivity and low permeability, and is widely used in the manufacture of heat exchangers, reaction tanks, absorption towers, filters and other equipment in the chemical industry.Natural graphite and polymer resin composites can also be used in the above fields, but thermal conductivity, corrosion resistance than artificial graphite.

Application prospect of graphite
 
With the development of research technology, the application prospect of artificial graphite is immeasurable.At present, using natural graphite as raw material to develop artificial graphite products can be regarded as one of the important ways to expand the application field of natural graphite.Natural graphite as an auxiliary raw material has been used in the production of some artificial graphite, but the development of artificial graphite products with natural graphite as the main raw material is not enough.The best way to achieve this goal is to fully understand and utilize the structure and characteristics of natural graphite, and to produce artificial graphite products with special structure, properties and USES by adopting appropriate processes, routes and methods.