1 School of Environment and Resources, Southwest University of Science and Technology, Mianyang 621010; 2 Key Laboratory of Solid Waste Treatment and Resource Recycle of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010; 3 Institute of Mineral Materials and Application, Southwest University of Science and Technology, Mianyang 621010
Abstract: The centrifugal separation and purification of microcrystalline graphite was carried out by using modified Hummers method with Hunan Chenzhou natural microcrystalline graphite as raw material. The result revealed that the oxygen-containing functional groups are bonded to the structure, the interlayer space are increased, the microcrystalline graphite aggregates become loose and the aggregates are partially dissociated after oxidizing, the particle size decreases gradually with the increase of the oxidation degree. After washing, the impurity can be separated from the microcrystalline oxidized graphite, and the graphite with high purity is obtained. Through the analysis of the structure and composition of the product, it shows that the oxidation plays a key role in the purification process. The oxidation has a chemical dissociation effect on the aggregates. The higher the oxidation degree is, the more obvious the dissociation effect is. When the mass ratio of microcrystalline graphite to KMnO4 is 1∶4, the best purification effect can be achieved. After purification, fixed carbon is 98.8%, volatile content is 0.2%, the ash content is only 1%, and the aggregates are completely dissociated, the diameter of the slices was 1—2 μm.
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