There are three forms of natural graphite: amorphous graphite, flake graphite and crystalline vein graphite. They have their own unique characteristics, which make them very suitable for some applications.

What is amorphous graphite?

Amorphous graphite is usually formed by contact metamorphism between anthracite coal seam and modifiers (such as tectonic stress, magma, etc.). The result is microcrystalline graphite, often referred to as amorphous graphite. Amorphous graphite is the lowest grade but the most abundant among the three kinds of natural graphite. It accounts for about half of the global supply of natural graphite.

In a few cases, if larger modifiers come into contact with anthracite coal seams, regional metamorphism will lead to amorphous graphite. However, this regional metamorphism is not common and a single joint of graphite is usually found.

Because amorphous graphite is made from anthracite coal seam metamorphism, graphite itself is a kind of coal seam mineral (not vein mineral).

As a kind of joint mineral, the ash content of amorphous graphite is often higher than that of other kinds of natural graphite. This is the result of the deposition of other organic matter when the modifier interacts with anthracite. After all, the coal production environment is often rich in organic matter. In addition, the graphite material may be free or mechanically attached to quartz or other materials.

The addition of organic materials makes amorphous graphite the least of the three kinds of natural graphite. Its crystallinity is relatively poor and usually shows a graphite content of 20% to 40% after mining. In contrast, other forms of natural graphite can have up to 90% graphite content.

Although all the natural graphite must be processed before use, amorphous graphite must be processed most extensively because of its low graphite content.

What is amorphous graphite used for?

Its high heat resistance makes the mineral easy to manufacture and is commonly used in crucibles, moulds, ladles, grooves and nozzles. Even the electrodes in many metallurgical furnaces and the lining of ferrous furnaces are made of amorphous graphite.

In iron and steel production, amorphous graphite can be added as a carburizer to improve strength and durability.

In other industries, amorphous graphite is used to make brake pads, clutch materials, washers and pencil leads. Pencil leads are usually made of the lowest quality amorphous graphite, and this special use is mainly found in China.

What is flake graphite?

Natural flake graphite is formed when carbon materials are subjected to high pressure and high temperature. Carbon source materials can be organic or inorganic, although most flakes of graphite from commercial sources come from organic deposits. The required pressure is usually greater than 1 Gipascal (75000 psi) and the required temperature is usually higher than 750C (1380 F).

Because natural flake graphite is formed when carbon deposits are subjected to pressure and temperature, graphite is most common in metamorphic rocks, and the sediments are evenly distributed throughout the rocks. Graphite has large flakes, medium flakes and fine flakes.

Depending on the use, the purity and / or size of natural flake graphite may be more important. The spherical industry needs flake graphite with large size and high purity, while the refractory industry mainly focuses on flake size.

What is flake graphite used for?

Although the spherical and refractory industries need natural flake graphite, the biggest buyer of this natural graphite is the automotive industry. Specifically, manufacturers of electric, hybrid and fuel cell vehicles have seen a significant increase in demand for flake graphite over the past few years.

Almost all environmentally friendly cars or trucks need flake graphite to run. Graphite is a key component of lithium-ion batteries used in electric vehicles and hybrid electric vehicles, and it also exists in fuel cells. In fact, fuel cells need more flake graphite than lithium-ion batteries.

Flake graphite is also used in vanadium redox batteries and nuclear reactors. Vanadium redox battery uses the chemical properties of vanadium and graphite to store excess energy reliably for a long time. The nuclear reactor wraps the uranium in large graphite balls.

What is vein graphite?

Crystal vein graphite is also called crystal vein, Sri Lankan graphite, Ceylon graphite, graphite. The names of Sri Lanka and Ceylon come from the areas where the graphite is mined. It is procured and processed only in Sri Lanka (formerly Ceylon), although this form of natural graphite is also found in the United Kingdom and the United States.

The exact formation of vein graphite is uncertain, but it is suspected that graphite is a natural pyrolytic graphite. If it is deposited directly from the fluid phase, as this theory suggests, it will explain the graphite veins found in ore and rock.

Generally speaking, solid graphite carbon may be deposited when high-temperature fluids flow. Once the fluid cools, the graphite carbon forms a graphite flow or vein in the surrounding rock. Carbon-rich gases may react with high-temperature fluids to form deposited graphite solids, or they may be absorbed as the fluid flows.

This formation helps to form a macro shape, just like a small needle perpendicular to the wall of the vein. The veins of this natural graphite can range from a few centimeters to two meters thick. At the time of purchase, the size of graphite ranges from fine to 5 micron powders to lumps up to 8 cm in diameter.

In many ways, vein graphite is the best quality natural graphite. Its graphite content can be between 94% and 99%, and the purest sample comes from the middle of the vein. Compared with other types of natural graphite, it also has higher thermal conductivity and electrical conductivity, and higher cohesion integrity. These properties may be attributed to its needle-like structure.

What is crystal vein graphite used for?

Veined graphite can be potentially used in any situation suitable for natural flake graphite, but the performance of veined graphite is slightly better. It is commonly used in automotive applications, such as high-performance clutches and brakes.

Where can I buy graphite powder?

RBOSCHCO is a trusted graphite supplier. We have flake graphite powder, spherical graphite powder and other types. We ship our goods all over the world.

If you are looking for high purity graphite powder, please send an email. (sales1@rboschco.com)

tags: semiconductor semiconductor material