Graphite mainly refers to natural graphite, which is a non-metallic mineral formed by carbon element under specific high-temperature reduction conditions, and is most commonly found in marble, schist, and gneiss.
Graphite is widely used in the fields of iron and steel, chemical industry, machinery, electronics, aerospace, national defense, military and other fields due to its many characteristics such as good high temperature resistance, thermal shock resistance, electrical conductivity, lubricity, chemical stability and plasticity An important strategic resource indispensable in the development of military industry and modern industry. Because graphite is widely used, some experts predict that the 20th century will be the "silicon era" and the 21st century will be the "graphite era."
According to the crystalline form of graphite, natural graphite can be divided into crystalline graphite and cryptocrystalline graphite.
Crystalline graphite flotation
Flake graphite has good natural floatability and low density, so coarse-grained flake graphite is easier to float. The flotation collector can be used kerosene, diesel oil, foaming agent commonly used pinol oil. Most of the flake graphite ore contains gangue minerals such as calcite and pyrite, and lime, water glass and other inhibitors need to be added; for carbonaceous shale, starch and lignin sulfonic acid can be added as inhibitors. Rare metals such as vanadium contained in graphite ore should be recovered to improve economic efficiency.
Stage flotation: In order to protect the scales from damage, the stage grinding and flotation process is used; after rough grinding, coarse separation is carried out to obtain coarse concentrate and abandoned tailings, and then the coarse concentrate is regrinded and reselected several times.
Multiple selections: The coarse concentrates obtained through rough separation are of low grade, while graphite products generally require fixed carbon content of more than 85%, which requires multiple selections.
Cryptocrystalline graphite flotation
Cryptocrystalline graphite has a poor natural floatability and a high grade of raw ore, which can reach 70% -80% or more. However, graphite particles and clay are closely embedded and it is difficult to separate them. In industrial production, the grade of cryptocrystalline graphite concentrate can be increased to more than 80% through grinding and flotation, but it is difficult to reach 90%, even if the number of regrinds is increased, the grade of concentrate is not much improved. Cryptocrystalline graphite flotation can only play a roughly enriching role, so concentrate and tailings can be sold as different grades of products. The characteristics of cryptocrystalline graphite flotation: the amount of flotation collector is large, the flotation speed is slow, the recovery rate of concentrate is low, and the grade of tailings is high.