Graphite is a kind of natural mineral elements, which is an allotrope of carbon with diamond. The chemical composition of graphite is carbon (C). Graphite crystals have typical lamellar structure. The carbon atoms are arranged in six layered meshes. The carbon atoms on the surface nodes are centered on the upper and lower neighbouring layer grids (figure 1). The number of repeat layers is 2, which is a common 2H polymorphism. Graphite is soft, soapy, with hydrophobic natural resistance to high temperature, good thermal and electrical conductivity.
Figure1. Graphite crystal structure
Graphite is widely used in metallurgical, mechanical, electrical, chemical, petroleum, nuclear industry, national defense industry and other areas.
1.The type of graphite ore
The graphite ore is divided into two types: crystalline (scaly) graphite ore and microcrystalline (soil like) graphite ore.
The graphite crystals of the crystalline (scaly) graphite ore are larger than 1 μm and are flaky. The ore is characterized by a low fixed carbon content, but a good alternative. Because of low fixed carbon content, this kind of ore can not be used directly in industry, so it needs to be treated by mineral processing to obtain the desired graphite products.
The diameter of graphite crystals in microcrystalline (soil) graphite ores is less than 1μm, showing a microcrystalline aggregate. The fixed carbon content of the ore is high, but the selectivity is poor, and the beneficiation effect is not good. At present, the industry can be used only after hand selection and grinding into powder.
2.Distribution of graphite ore
World graphite resources are mainly concentrated in China, Brazil and India, followed by Czech, DPRK, Mexico, Madagascar, Canada, Sri Lanka and other countries. China's Graphite resources account for 70% of the world's total graphite resources.
3.The mineral processing way of Graphite ore
The fixed carbon content of crystalline graphite ore is low, and it can not be used directly in industry. It needs to be beneficiate to obtain the desired graphite products. Graphite is a floatability, so the mineral processing method of graphite ore is mainly flotation.
Scale graphite scales vary greatly in size, and their use and value vary greatly. Large scale wide use, the price is several times higher than in fine scale. Therefore, the mineral processing of graphite ore requires not only the higher grade and the recovery rate, but also the scale of the graphite, and the scale is not destroyed as much as possible.
In view of the special requirements for graphite ore beneficiation products, the process of mineral processing mostly adopts multi section grinding and multi section selection process. When ore contains a large amount of large flake graphite, it is the main factor to make the beneficiation process to protect the flake from being damaged. For the beneficiation of fine scale graphite ore, high grade concentrate should be obtained.
In the period of grinding, multi section processing flowsheet, middling return number, different properties, middling return position selection is directly related to the rationality of the process structure.
3.1.The beneficiation of crystalline (scaly) graphite ore
The grade of scaly graphite ores is generally 2.13% to 15%, and the main processing method is flotation. In flotation, the commonly used collectors are kerosene, diesel, heavy oil, sulfonate, sulfuric acid, phenols, carboxylic acids, etc. commonly used foaming agents are pine gum oil, No. four oil, ether alcohol, butyric acid oil and so on, and inhibitors are lime, sodium silicate and so on. The ore concentrate regrinding times multiple selection (typically 3 to 6 times), or return to the order of the middlings closed flotation, above the grade of concentrate was 90%, the recovery rate of about 80%. Figure 2 is the process flow chart of the scale graphite mineral processing. The application of the main equipment are jaw crusher, ball mill, spiral classifier, flotation machine, conditioning tank, thickener, vacuum filter etc..
Figure2. flowchart of crystalline Graphite ore beneficiation
3.2. The beneficiation of microcrystalline graphite
Microcrystalline graphite usually has a high grade of crude ore, usually 60%-90%. After crushing and grinding, it can get the finished product. If flotation is used, concentrate tailings are finished products, and the concentrate grade is generally 90%. Figure 3 is the processing flow of microcrystalline graphite ore. The common equipment is jaw crusher,spring cone crusher, Raymond mill, vibrating screen and so on.
Figure 3.flowchart of microcrystalline graphite ore beneficiation
Related you may like:
---Crushing and screening automatic control
---Grinding and classifing automatic control
---General layout of mineral processing plant
---Dewatering workshop arrangement
---Gravity separation workshop arrangement
---Magnetic separation workshop arrangement
---Ore washing process and workshop configuration
---Crushing and screening plant layout design
---Ball mill and flotation machine workshop arrangement
---Structure and features of vibrating screen
---Structure of overflow ball mill and rod mill
---Grinding ball mill structure
---beneficiation experiment- ore sampling
---Mineral magnetic separation
English
Español
简体中文