| Graphite is the one of advantage mineral of our country, which has been listed as a national strategic resources. But with the development and utilization of resources, the quality of flake graphite resources become less and less.and the level of processing of graphite mineral in our country is still low;the flake structure of graphite is severely damaged during the regrind process,and the production rate of large flake graphite(generally refers to+0.15mm) is low, just only about20%on average. However,compared with the fine flake graphite, the large flake graphite have greater value.and the key point of flake graphite processing is try to protect large flake will not be destroyed.Therefore, based on the problems of protecting large flake graphite in graphite processing fields, this paper takes the graphite of Yi Chang prefecture as raw materials and adopts the new type of vertical stirred mill as the regrind device, to explore how to keep the graphite flake from damaging as much as possible during the grind process, to improve the production rate of the lager flake graphite and the quality of products, which has important economic significance to give full develop the graphite resources in our country.Study how to protect the large flake of graphite,we should have the appropriate methods to express it. The author through this study found that with the damage coefficient formula of L is appropriate and right which to represent the graphite grinding effect is good or bad.Through the grinding effect of contrast experiment,which compare ball mill with vertical stirred mill the,we found that with vertical stirred mill to protect the graphite flake have a better effect.Using vertical stirred mill to conduct four times regrind experiment of graphite, which is concluded that the best grinding conditions to protect graphite’s large flake are:under certain conditions that the amount of ore、the filling rate、the grinding concentration were sure and the dielectric sphere all using Φ6mm new ceramic ball, the best conditions of the first section of regrinding for using100r/min and grinding3.5min; the second section for using130r/min and grinding5.25min; the third section for using100r/min and grinding4.1min;the fourth section for using115r/min and grinding5min.About the graphite which grade is11.79%, the authors performed one roughing experiment and according to the best grinding conditions to do four grind and five cleaning closed circuit experiment with rough concentrate,which can get a good index with the grade at94.12%. recovery rate of94.68%and yield of11.86%.The+0.15mm level yield of54.88%in the concentrate products which far more than the24.56%of the index in the processing plant, and shorten the grinding-flotation process.The analysis of the ball mill and the vertical stirred mill medium movement shows that dielectric sphere movement is mainly give the impact and collision to cylinder wall in the ball mill,and the impact force of the grinding medium is not easy to occur in the flake between layers, but will impact on the surface of flake,which lead to the surface of graphite flake appear erack or damage.However the dielectric sphere movement is mainly to bring shear/frietion in the vertical stirred mill,and shear force can effect from the between layer and layer of graphite better,which can peel off the flake of graphite and avoid the flake structure from destructing. |
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