Pure graphite is a mineral form of the element carbon (atomic number 6) and its symbol is C. It forms in veins in metamorphic rocks as the result of the metamorphism of organic material included in limestone deposits. It is an extremely soft mineral at 1 to 2 on Mohs' hardness scale. It is black and has a black streak. "Streak is the color of a mineral when it is crushed to a powder". For centuries due to its softness and streak, It has been used mostly in making "Lead" for pencils.
Crystals are uncommon, but when they occur, they are found as rough, six-sided (hexagonal) flakes, as in the drawing. It breaks into minute, flexible flakes that easily slide over one another. Mineralogists call this basal cleavage. This feature is the cause of graphite?s distinctive greasy feel. It is this greasy characteristic that makes graphite a good lubricant. Because it is a solid material, it is known as a dry lubricant. Graphite is the only non-metal element that is a good conductor of electricity. In nature, graphite is found in two distinct forms, flake graphite and lump graphite. Lump graphite is more compact than flake and lacks the distinctive flaking mentioned earlier.
The Name Graphite was named from the Greek Verb graphein meaning to write, Since graphite was used in the manufacture of pencils. The name was given by Abraham Gottlob Werner in 1789.
Its "Old World" (that is, old European) name was plumbago which means black lead, a reference to its use in pencils.
Because graphite flakes slip over one another, giving it its greasy feel, graphite has long been used as a lubricant in applications where wet lubricants, such as oil, can not be used. Technological changes are reducing the need for this application.
Natural graphite is used mostly in what are called refractory applications. Refractory applications are those that involve extremely high heat and therefore demand materials that will not melt or disintegrate under such extreme conditions. One example of this use is in the crucibles used in the steel industry. Such refractory applications account for the majority of the usage of graphite.
It is also used to make brake linings, lubricants, and molds in foundries. A variety of other industrial uses account for the remaining graphite consumed each year.
Substitutes and Alternative Sources
Molybdenum disulfide is a good dry lubricant substitute for graphite. However, unlike graphite, molybdenum disulfide is not as stable in oxidizing conditions. Manufactured graphite powder can be used in the steel industry. However, as long as graphite deposits remain abundant, and the cost of raw graphite remains low, producing large quantities of manufactured graphite will be unnecessary for many years to come.
It is estimated that the world reserves of graphite exceed 800 million tons. China is the most significant graphite-producing nation, providing nearly one-half of the United States? annual graphite demand. Flake graphite is also imported to the United States from Brazil, Canada, and Madagascar. Lump graphite is imported from Sri Lanka. Graphite resources in the United States are very small. At one time a significant deposit at Ticonderoga, New York, was exploited, but this source no longer produces graphite. For a number of years, the United States has not produced natural mineral graphite and is completely dependent on the combination of imported, synthetic graphite, and recycled graphite sources.
SOURCES FOR THIS
GRAPHITE IN TANZANIA
Graphite in Tanzania is found in Mererani where Tanzanite gemstones are mined, Mererani is a district within the Arusha Region. There is another region also in Tanzania where graphite is also found but we cannot disclose that place in the public domain, We happen to own that area its a huge area it can produce up to 1000 tons weekly and also its graphite it has 99% Graphite Content compare to the Mererani which is less in content due its mixture with pyrity.
Graphite availability in Mererani its not that huge production. Infact when you reach Mererani all the Tanzanite Miners are dark in colours due to the sand coming out in the holes where Tanzanite gemstones are mined. All the Miners their clothes are covered with Graphite Dark dust. Infact for any experienced Tanzanite Miner when you reach a belt where there is a lot of graphite within the vein and also the Graphite is adhered with Pyrite then you know anytime you will reach the Tanzanite gemstones pockets.
There was a Company which was Mining Graphite from South Africa in Mererani but 2 years ago they did close their Company Production Unit. But they were producing enough for the supply in South Africa Market.
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