Common preparation methods of expandable graphite
1. Chemical intercalation method: the initial raw material for preparation is high carbon flake graphite. Other chemical reagents, such as concentrated sulfuric acid (over 98%), hydrogen peroxide (over 28%), potassium permanganate, etc., all use industrial grade reagents. The general steps for preparation are as follows: under appropriate temperature, hydrogen peroxide solution, natural flake graphite and concentrated sulfuric acid with different ratios are added in different procedures, reacted for a certain time under constant stirring, and then washed to neutral, Centrifuge, dehydrate and then vacuum dry at 60 ℃.
2. Electrochemical method: the graphite powder is treated in a strong acid electrolyte to make expandable graphite, which is hydrolyzed, cleaned and dried. As a strong acid, sulfuric acid or nitric acid is mainly used. The expandable graphite made by this method has low sulfur content.
3. Ultrasonic oxidation method: In the process of preparing expandable graphite, the anodized electrolyte is subject to ultrasonic vibration. The time of ultrasonic vibration is the same as that of anodic oxidation. Since the ultrasonic vibration of electrolyte is conducive to the polarization of cathode and anode, the speed of anodic oxidation is accelerated and the oxidation time is shortened.
4. Vapor phase diffusion method: the graphite and the intercalation are respectively sent to the two ends of a vacuum sealed tube, heated at the end of the intercalation object, and the temperature difference at the two ends is used to form the necessary reaction differential pressure, so that the intercalation object enters the flake graphite layer in the state of small molecules, so as to produce expandable graphite. The number of layers of expandable graphite produced by this method can be controlled, but its production cost is high.
5. Molten salt method: several inserts are mixed with graphite and heated to form expandable graphite.
After the project is completed, the annual output of spherical graphite will be 2,000 tons, and the annual sales income will be 120 million yuan.
Shandong is one of China's important industrial base provinces. Especially since the reform and opening up, Shandong has not only occupied an important position in the light industry, but also the chemical industry has developed rapidly. After more than two decades of reform and opening up, it has already had a solid foundation.
In 2011, the export situation of flake graphite was relatively sluggish.
Spherical graphite is made of high-quality high carbon natural flake graphite by using advanced processing technology to modify the surface of graphite to produce graphite products with different fineness and oval shape.
High purity graphite means that the carbon content of graphite is more than 99.99%.
Qingdao Jinhui Graphite Co., Ltd.
Nantanpo Village, Zhangshe Town, Pingdu City, Qingdao, Shandong Province, China
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