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Natural Amorphous Graphite

Typical Chemical Analysis, Loss on Ignition at 950 degrees Celsius

Total Carbon + Ash = 100%
Fixed Carbon = Total Carbon – Volatile Matter

Typical Ash Analysis

Physical and Chemical Characteristics

Natural graphite is an allotrope of carbon. It is a soft mineral, ranging in color from gray to black, with a metallic luster. It has a specific gravity of 2.23, a hardness of 1-2, and crystallizes in the hexagonal system. It is stable and chemically inert at normal temperatures, odorless, non-toxic, heat resistant, and an excellent conductor of heat and electricity. It has a slippery texture.

Graphite is extremely refractory and is minimally affected by temperatures exceeding 3,000ºC. It exhibits high resistance to weathering and acids and readily mixes with other materials, both liquids and solids. It is compressible and malleable, resistant to chemical attack, thermal shock, contraction, and oxidation. It has low coefficients of friction, thermal expansion, and permeability. It remains flexible and sectile over a wide range of temperatures and is an excellent lubricant.

In nature, graphite is found in small hexagonal crystals in the form of compacted, scaly, earthy, and spherical aggregates. It is often associated with minerals such as quartz, feldspar, mica, calcite, pyrite, and iron oxides.

The electrons located between layers are responsible for conducting electricity and also give graphite its luster as light is reflected off the electron cloud. Graphite has excellent wear resistance properties, particularly with soft metals. It is insoluble in water and does not melt at high temperatures but transitions directly to a gaseous state (sublimation) at temperatures above 3,800°C.

In the absence of oxygen, graphite withstands heat very well. It also resists the action of bases and non-oxidizing acids but readily reacts with oxidizing acids, forming interlayer compounds containing oxygen and hydrogen. The ideal limit composition may correspond to the formula C2O. This interlayer compound is known as graphite oxide. Treating graphite with fluorine at a temperature of around 500°C results in the formation of an interlayer compound with the formula (CF)n.

When an element like magnesium is added and the appropriate treatment is applied, graphite that has taken on a laminar form during solidification acquires a spheroidal shape, giving rise to nodular graphite or ductile iron. This type of iron is characterized by good resistance to natural corrosion, vibration absorption capacity, self-lubrication, and higher mechanical properties. It has superior deformability before fracture compared to lamellar or gray iron, a modulus of elasticity similar to steel, and 2-3 times higher tensile and flexural strength than lamellar or gray iron. It also exhibits high resistance to shocks.

Some new applications include electrically conductive asphalt for heated runways at airports and road bridges. In graphite, carbon atoms are bonded in groups of six, forming a hexagonal shape. The bonds within each hexagon are strong, but those between hexagons are weaker. This allows groups of atoms to slide or change position, making them easily separated. Hence, graphite is soft and slippery.

The way carbon atoms in organic substances bond together in chains is exceptional. The vast number of carbon organic compounds is a result of the different arrangements of atoms when they bond in open or closed chains. This is why there are so many organic carbon compounds. Carbon is involved in the formation of complex compounds in all living matter.

In Mexico, graphite is primarily used in the iron and steel industry. It is also used in the production of refractory products, chemicals, coatings, and due to its self-lubricating and electrical conductivity properties, it is used in the manufacturing of conductors in electric motors and dry batteries.