Expandable Graphite
Size
0.50mm or 0.106mm, etc
Package
25 kg small bags into ton bags
Origin
China
Features
Preservative/Electrical and thermal conductivity, etc.
Application
Fireproof sealing element, flame retardant, refractory brick, etc.
Expandable graphite crystal is a typical layered carbon material. Other heterogeneous particles such as atoms, molecules, ions, and even atomic clusters are inserted into the interlayer of crystalline graphite by physical or chemical methods to form a new layered compound, which is called graphite interlayer compound, namely expandable graphite.
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Our country is rich in graphite mineral resources. It mainly uses flake graphite in natural graphite as raw material to purify and produce high-carbon graphite, that is, high-purity graphite and expandable graphite. This type of graphite is superior to other types of graphite in floatability, lubricity, and reversibility. , the largest industrial value.
Expandable graphite crystal is a typical layered structure carbon material. Other heterogeneous particles such as atoms, molecules, ions and even atomic groups are inserted into the crystal graphite layer by physical or chemical methods to form a new layered compound, which is called It is called graphite interlayer compound, that is, expandable graphite. Expandable graphite and expanded graphite are different, and expanded graphite should be selected for sealing strips.
Differences between expandable and expanded graphite
Expandable graphite is an interlayer compound of natural flake graphite (or artificial graphite with a high degree of graphitization) treated with an acidic oxidant (sulfuric acid, nitric acid, hydrogen peroxide, potassium permanganate), also known as graphite oxide. The immersion of the oxidant also causes the original graphite to produce a small expansion behavior, and the interlayer distance increases from the original 3.35A to 6-11A. The important feature of graphite oxide is its unique expansibility, which can expand at high temperature, so it is expandable graphite;
Different from graphite, graphite oxide can form a stable graphite oxide colloid or suspension in water or alkaline water under the action of external force, such as ultrasonic waves. -Layers peeled off. Expanded graphite is the action of graphite oxide at a high temperature of 960-980°C. The compound between the graphite layers gasifies and decomposes rapidly, generating a certain amount of thrust, which destroys the molecular force of the bond between the graphite layers, and breaks the C-C bond between the graphite lattices. Rapidly expands along the c-axis direction, and the interlayer distance increases by 50-500 times, changing from denser flake-like graphite to flocculent worm-like graphite.
How expandable graphite becomes expanded graphite
Expandable graphite is a kind of graphite intercalation compound formed by the oxidation and intercalation of natural flake graphite to insert foreign substances into the graphite sheet. At present, the chemical oxidation method is the most widely used in the industrial preparation of expandable graphite, followed by for the electrochemical method. The main process of preparing expandable graphite by chemical oxidation is to add oxidant and intercalant solution to natural flake graphite. Under the condition of strong oxidant, the edge of graphite is oxidized and loses electrons to be positively charged, and the positive charges repel each other, resulting in a larger edge distance between graphite layers, so the intercalation agent can effectively enter the graphite layer for intercalation reaction and form an interlayer compound. . Expanded graphite is a loose and porous worm-like substance formed by the rapid expansion of expandable graphite under high temperature conditions.
Expanded graphite mainly produces graphite paper and processes various graphite gasket sealing materials, also known as flexible graphite, which has the advantages of high temperature resistance, high pressure resistance, good sealing performance and corrosion resistance to various media, and is currently a new type of advanced sealing material. Expanded graphite has high thermal conductivity, and it can be used as thermal and conductive materials by utilizing the characteristics of flexible graphite. Therefore, it cannot be used to make sealing strips for fire doors.
Franli’s factory produces expandable graphite and high-purity graphite. We consistently update our technology and are committed to producing high-quality products. If you need it, please contact us. We have a professional team.
