Grafite natural versus grafite sintético: Uma comparação detalhada

Graphite is a multipurpose compound used in various industries, such as energy, lubricants, electronics, and more. Nevertheless, most people do not know that it is available in two forms: natural graphite and synthetic graphite. This guide does a comparative analysis of both graphite types. It gives you clarity on their compositions, applications, and manufacturing.

Overview of Nature Graphite

Natural graphite is an organic compound made primarily of carbon. When carbon-rich material gets exposed to high pressure and heat inside the rock, graphite forms. This process takes millions of years to complete.

Miners excavate natural graphite from the earth in various forms. However, three primary forms of natural graphite include:

Amorphous

Amorphous graphite features a disordered structure due to the random arrangement of carbon atoms. This natural graphite forms due to the contact metamorphism between an anthracite coal seam and a metamorphism agent, such as magma or tectonic stress.

Flake

Natural flake graphite forms when carbon is exposed to high pressure and temperature. The flake is generally sourced from metamorphic rock deposits. This graphite form is thin, flat, and features a hexagonal layer.

Crystalline

Crystalline graphite is known for its regular atomic structure. The carbon atoms of this graphite are arranged in a hexagonal lattice.

Overview of Synthetic Graphite

Synthetic graphite is a man-made compound prepared in a factory. This artificial graphite forms when carbon-containing materials, such as coke, coal tar pitch, etc., are exposed to high temperatures in a furnace.

Unlike natural graphite, this compound has precise properties. Since it is man-made, you can control its grain size, purity, and density.

The appearance of synthetic graphite is more consistent. Furthermore, its flakes are softer than that of natural graphite.

Let us compare different aspects of natural graphite and synthetic graphite.

Nature Graphite vs Synthetic Graphite: Comparison of Different Factors

Composition

Natural graphite comprises carbon and various impurities. It is primarily found in metamorphic rocks. The graphite forms due to the metamorphism of carbon-rich material.

The carbon content in natural graphite ranges between 15% and 95%. The remaining composition might be ash, iron, silica, sulfur, etc.

Synthetic graphite, on the other hand, contains 99% carbon. The remaining 1% contains volatile material and ash content.

Color

The shade of natural graphite ranges from dark gray to black. You can also notice a metallic sheen over it.

Generally, this color variation is due to impurities present in graphite. This graphite form is relatively more opaque.

The color of synthetic graphite is darker due to its high purity. Since it is a lab-made compound, it features a consistent appearance. Also, it has a uniform and smooth surface.

Manufacturing

As mentioned above, companies extract natural graphite from mines and quarries. This raw material undergoes various treatments to improve its quality. These processes eliminate impurities from graphite and maintain its particle size.

Chemical engineers heat petroleum coke or coal tar pitch at temperatures above 2,500 degrees Celsius. This graphitization process converts carbon materials into graphite.

Furthermore, it ensures crystalline structure in synthetic graphite because of aligned carbon atoms.

Chemical Properties

Natural graphite remains stable at room temperature. Under standard conditions, it is chemically inert. It means graphite won’t react to acids, alkalis, and other solvents. However, organic graphite can oxidize at temperatures around 600 °C.

Synthetic graphite has an extremely high tolerance against chemicals. Its high density and low porosity make it resistant to various types of substances.

Physical Properties/Density

The density of natural graphite ranges between 1.5 to 1.8 g/cm³, depending on its type. Flake and amorphous graphite may have slight variations in their structure and composition.

Synthetic graphite is slightly denser than the natural ones. Its solidity ranges between 1.6 to 1.9 g/cm³. Moreover, as the purity level is higher in this graphite, it has better thermal and electrical conductivity.

Price

The price of graphite may vary based on various factors. Depending on the type, grade, and market demand, the price of natural graphite can range between USD 500 and USD 2000 per ton.

Synthetic graphite is expensive. Its price starts from USD 3,000 per ton. The cost of some premium synthetic grades can go up to USD 20,000 per ton.

Nature Graphite vs Synthetic Graphite: Applications

Natural Graphite

Refractories

Natural graphite is commonly used in making bricks and crucibles. Besides this, you can notice its usage in crafting molds in industries like steel and glass. After all, it has high heat resistance.

Lubricants

Natural graphite features a slippery layered structure. As a result, companies use it in lubricants and greases as main ingredients.

Pencils

Natural graphite is also used to make pencil leads. After all, this compound leaves a mark on paper.

Batteries

Battery manufacturers use natural graphite as the anode material in some lithium-ion batteries. It is common in lower-cost batteries that do not need as much power or performance.

Foundry

Natural graphite is a primary ingredient in the casting and foundry industry. Companies use it as a parting agent to prevent molds from sticking to the metal during casting.

Brake Linings

Natural graphite has outstanding frictional properties. Consequently, automobile companies use it to make brake linings and gaskets.

Applications of Synthetic Graphite

Electrodes

Synthetic graphite is capable of enduring high temperatures. Furthermore, it is highly conductive. Consequently, electrode manufacturers use it to make graphite electrodes for electric arc furnaces.

Lithium-ion batteries

Synthetic graphite is used as the anode material in lithium-ion batteries for EVs. This graphite is purer and more consistent in structure, which improves battery performance.

Fuel Cells

Synthetic graphite is also used in the production of bipolar plates in proton exchange membrane fuel cells (PEMFC).

Nuclear Industry

This man-made synthetic graphite has high thermal stability. Nuclear engineers use it as a moderator and reflector in nuclear reactors.

Synthetic graphite slows down neutrons and sustains nuclear fission.

Conclusão

This is a comprehensive look at how natural graphite compares to synthetic graphite. Both are valuable compounds used in various industries.

Nature graphite is affordable and suitable for applications where high purity of graphite is not required. On the contrary, synthetic graphite is expensive. However, it is suitable for applications that need the purest form of graphite. After all, it provides consistent performance.