Graphite is a allotrope of carbon, which can be divided into block graphite, flake graphite and aphanitic graphite. Its crystallinity and scale size determine the graphite beneficiation process. The industrial value of block graphite is not high, so most of it is not used; Although scale graphite and aphanitic graphite have high industrial value, it is difficult to beneficiate them.
In this paper, micro flake graphite and aphanitic graphite are selected as the representatives, and the differences between the two graphite beneficiation processes are discussed from four aspects: grinding mode, grinding concentration, middling return mode and reagent dosage.
Because the embedded particle size of fine flake graphite is very fine, the grinding strength of the second grinding section is relatively large for the fine flake graphite, which can directly grind the ore to a finer fineness, while the subsequent regrinding mainly plays a role in cleaning the flotation concentrate. When the fine flake graphite is grinded for another section, the grinding fineness can directly reach the standard, and the subsequent regrinding operation has almost no impact on the grinding fineness.
With the increase of the number of regrinding segments, the grinding fineness of aphanitic graphite ore gradually becomes smaller. Although the embedded grain size of aphanitic graphite is also very fine, because the ore is easy to be slimed, the grinding fineness is too fine, which will cause gangue mineral entrainment. Therefore, it is recommended to grind the aphanitic graphite gradually during the grinding process.
The grinding concentration of fine flake graphite and aphanitic graphite depends on the content of fixed carbon in the graphite. If the fixed carbon content of raw graphite ore is low, the grinding concentration is low, and the concentrate yield is low, and vice versa. Therefore, in order to improve the grinding efficiency, the fine flake graphite can concentrate the selected foam products before regrinding to improve the grinding concentration and the yield of coarse concentrate.
The hardness of aphanitic graphite ore is relatively high. In order to save grinding time, the higher grinding efficiency and higher grinding concentration can be selected during rough grinding to improve the recovery rate.
As the graphite and gangue minerals in micro flake graphite are easy to separate, the middlings can be effectively separated after returning. However, the floatability of aphanitic graphite is worse than that of fine flake graphite. It is not easy to separate graphite from gangue minerals. The return of middlings is not conducive to separation, and may even deteriorate the flotation indexes.
Therefore, it is suggested that the middlings of fine flake graphite should be returned separately, and the middlings of aphanitic graphite should be treated separately to recover fixed carbon more effectively.
Generally speaking, the overall dosage of micro flake graphite and aphanitic graphite ore is large, which is related to the size of graphite embedded. The graphite in micro flake graphite is in flake shape, and the graphite in aphanitic graphite ore is in aphanitic shape. The natural floatability of flake graphite is better than that of aphanitic graphite. Therefore, in order to achieve the same flotation effect, the dosage of aphanitic graphite is significantly higher than that of micro flake graphite.
For fine flake graphite, before the amount of collector reaches the critical point, the increase of its amount is conducive to the increase of fixed carbon content of coarse concentrate, while the change of the amount of foaming agent has little impact on the fixed carbon content of coarse concentrate.
For aphanitic graphite, the excessive increase of the amount of collector and foaming agent will lead to the decrease of the fixed carbon content of the coarse concentrate. Therefore, the dosage of reagents should be appropriately selected according to the specific conditions of graphite ore.
The above is the difference of mineral processing technology between micro flake graphite and aphanitic graphite in four aspects. It is recommended that all mine owners consult with professional concentrators before the establishment of concentrators, determine the properties of graphite ore, and customize professional beneficiation schemes to achieve an ideal rate of return on investment.
