| China is very rich in graphite, with reserves and production and sales volume ranking first in the world. Because of the unique physical and chemical properties, flake graphite has been widely available in the metallurgical, electrical, chemical and other industrial field. On the one hand, big flake graphite (usually+0.3 mm,+0.18 mm) has higher economic value than the fine grade,and some fields such as crucible and expanded graphite manufacturing must use big flake graphite, fine-grained level can not be used. We can not produce big flake graphite under modern industrial technology, once destroyed it can not be restored. On the other hand,big flake graphite in China is of low-scale,and the graphite flake is ususlly severely damaged due to the complex re-grinding process, leading to low yield and short market supply. Therefore, studying how to protect the graphite crystal during graphite flotation not to be destroyed and exploring reasonable re-grinding process to improve the big flake yield and the quality of concentrate has great economic significance on the full resources of graphite.Process mineralogy studies on Graphite Mine in Anshan Xiuyan showed that the mine belonged to flake graphite ore, with fixed carbon content of 10.47%, mainly existing as scaly, single flaky or aggregates.The main gangue minerals are tremolite, quartz, mica, feldspar and so on. The results of disseminated characteristics of the graphite showed that the graphite mine contained 20%-30% of the+0.15 mm big particles.We should protect the big flake during mineral processing and improve the value of graphite products.Firstly, research on pharmacy conditions of rough selection was carried out Then the effects of different re-grinding equipment, grinding media and different proportions of the media on the protection of graphite crystals were studied,with the crude concentrate as raw material which was obtained from crude flotation under the the best agents conditions.The results showed that the vibration mill and column media could provide The best protection effect on the crysta.Finally,on the base of the best re-grinding process conditions, the tests of the rough concentrate re-grinding degree, open trial, the way back of middlings mine and closed-circuit process were all carried out.Ultimately, high quality concentrate was obtained with concentrate fixed carbon content of 96.34%, recovery rate of 94.11%,+0.15 mm level yield of 16.17% (fixed carbon content of 95.43%), tailings fixed carbon of 0.69%.Flotation mechanism showed that kerosene mainly adsorbed on graphite surface by physical adsorption, and adding sodium carbonate as a modifier in the mill can not only spread the sludge but also be used as aids to improve the grinding effect. Grinding kinetic theory studies showed that the impact force from grinding media may occur perpendicular fracture to the crystalline graphite flake,then would lead to more probability of big flake graphite destruction.The pan and peeling force along flake graphite crystalline level can make the flake graphite segregate easily along the dissociation level,then would decrease the probability of big flake damage.Therefore, vibration mill with the role of vibration and peeling was chosen as re-grinding equipment,which can better adapted to the layered crystalline characteristics of flake graphite.It can not only greatly improve the concentrate grade, but also provide better protection for big flake graphite.
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