Remove the impurities from the graphite raw ore and select the concentrate is the process of beneficiation. On the basis of concentrate to continue processing and improving the carbon content to realize high purity craft, this process is the purification process.
Natural graphite ore generally is divided into two groups: one is flaky graphite ore which the carbon content(3-30%) is low ,and the other is Microcrystalline graphite ore which is also can be called amorphous graphite (35~85%). The flaky graphite ore' flotability is good and the grade can be improves easily. In order to ensure its large flaky and precision, the multistage grinding and multistage flotation will be adopted. Our company has designed and constructed for many customers both at home and abroad for different outputs of the flaky graphite ore, the largest production line is 300 tons one day, and the grade can be up to 96%. The most multistage is 6 grinding stages and 7 flotation stages. Concentrate can be dived into 4 stages: high purity graphite is more than or equal to 99.9%, high-carbon graphite (94~99.9%), medium-carbon graphite（80~94%）and low carbon graphite（50~80%). The grade of microcrystalline graphite ore is generally higher and classification according the iron content. The flotability is poor and the usage is not very wildly. And purification process should be carried out later. Recent years, with the birth of new type collector, the time of the graphite beneficiation is shortened and the output is increased.
Graphite concentration process generally adopted the high temperature and acid pickling process and high temperature and evaporation process. Graphite ore resist acid and corrosion. Adding the sodium hydroxide to the concentrate ore, and heating to the 500 degrees, then the soluble silicate is produced and add water to eluting and concentrating, then add hydrochloric acid or sulfuric acid to wash off metal impurities. After chemical and acid process, almost all the metallic and non-metallic impurities are removed. Ultra-high temperature evaporator process takes advantages of graphite's performance of resistance to high temperature, and isolate from the air which is heated to 2500 to 2800 degrees. Most impurities evaporated by heat temperature and after cooling the purified graphite is produced. The purified graphite's carbon content can reach 99.9%.
The beneficiation of the graphite is mainly adopted the flotation process, in the process of concentrate ore to regrinding, generally the concentrate concentration is 30-35%, which need to be concentrated before regrinding, grinding concentrate concentration between 60-65% is better. When dealing with the microcrystalline graphite, due to the capacity is large, so the large thickener is needed. The common thickener not only occupy a large area, but also need large investment, what is more, due to the graphite density is small, the effect is not very good. Our engineers combined the advanced domestic and overseas technology, create a set of very effective and low investment crafts during the process of concentrate ore regrinding. Especially in Indonesia 1500 tons one day beneficiation process, which is designed for 6 grinding stages and 7 flotation stages, the concentrate grade is up to 96%, and the recovery more than 88% and less than 2% concentrate dewatering, grading of 50 mesh, 50-80 mesh, 80 ~ 120 mesh, 120 mesh or more, according to different size for sale , the design does not exceed the area of 6000 m2, which bring customers a great economic profits and won good fame .