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Convert coal into Nano graphite powder

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Author : NANOTRUN
Update time : 2021-07-30 09:04:21
Convert coal into Nano graphite powder
An international team of researchers proved that it takes only 15 minutes to convert pulverized coal into high-value Nano graphite. In the research published in the journal Nano-Structures & Nano-Objects, scientists explain how to use microwave ovens to create an environment where raw coal powder can be successfully converted into Nano graphite. Nano graphite can be used as a lubricant and used for everything from fire extinguishers to lithium Items such as ion batteries.
From their point of view, this "metal-assisted microwave processing one-step method" represents a simple and relatively inexpensive new method of coal conversion technology in order to make full use of the coal in the Powder River Basin of Wyoming. According to the team led by TeYu Chien at the University of Wyoming, although previous studies have shown that microwaves can reduce the moisture content of coal and remove sulfur and other minerals, most of these methods require special chemical pretreatment of the coal. However, in the experiment, the only treatment to be performed was to pulverize the raw coal from the Powder River Basin. Then put the powder on the copper foil and seal it in a glass container with a mixed gas of argon and hydrogen, and finally put it in a microwave oven.
The lead author of the paper, Chris Masi, stated: “By cutting the copper foil into a fork shape, microwave radiation will generate sparks, which can generate extremely high temperatures exceeding 1,800 degrees Fahrenheit within a few seconds.” Then, the high temperature transforms the pulverized coal. For polycrystalline graphite, copper foil and hydrogen also contribute to the conversion of this process. The team (which also includes researchers from New York, Nepal, and China) believes that this new coal conversion method can be improved and implemented on a large scale to produce higher quality and quantity of graphite nanomaterials.

What is Graphite
Graphite is a naturally occurring form of crystalline carbon. It is a native element mineral found in metamorphic and igneous rocks. Graphite is a mineral of extremes. It is extremely soft, cleaves with very light pressure, and has a very low specific gravity. In contrast, it is extremely resistant to heat and nearly inert in contact with almost any other material. These extreme properties give it a wide range of uses in metallurgy and manufacturing.
Graphite is a mineral that forms when carbon is subjected to heat and pressure in Earth's crust and in the upper mantle. Pressures in the range of 75,000 pounds per square inch and temperatures in the range of 750 degrees Celsius are needed to produce graphite. These correspond to the granulite metamorphic facies.
Most of the graphite seen at Earth's surface today was formed at convergent plate boundaries where organic-rich shales and limestones were subjected to the heat and pressure of regional metamorphism. This produces marble, schist, and gneiss that contain tiny crystals and flakes of graphite.
When graphite is in high enough concentrations, these rocks can be mined, crushed to a particle size that liberates the graphite flakes, and processed by specific gravity separation or froth flotation to remove the low-density graphite. The product produced is known as "flake graphite."
Some graphite forms from the metamorphism of coal seams. The organic material in coal is composed mainly of carbon, oxygen, hydrogen, nitrogen, and sulfur. The heat of metamorphism destroys the organic molecules of coal, volatilizing oxygen, hydrogen, nitrogen, and sulfur. What remains is a nearly pure carbon material that crystallizes into mineral graphite.
This graphite occurs in "seams" that correspond to the original layer of coal. When mined, the material is known as "amorphous graphite." The word "amorphous" is actually incorrect in this usage, as it does have a crystalline structure. From the mine, this material has an appearance similar to lumps of coal without the bright and dull banding.
Graphite and Diamond
Graphite and diamond are the two mineral forms of carbon. Diamond forms in the mantle under extreme heat and pressure. Most graphite found near Earth's surface was formed within the crust at lower temperatures and pressures. Graphite and diamond share the same composition but have very different structures.
The carbon atoms in graphite are linked in a hexagonal network which forms sheets that are one atom thick. These sheets are poorly connected and easily cleave or slide over one another is subjected to a small amount of force. This gives graphite its very low hardness, its perfect cleavage, and its slippery feel.
In contrast, the carbon atoms in diamonds are linked into a frameworks structure. Every carbon atom is linked into a three-dimensional network with four other carbon atoms with strong covalent bonds. This arrangement holds the atoms firmly in place and makes diamond an exceptionally hard material.
 
 
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