Study On The Fine Classification And Floation Technology Of Crystalline Graphite Based On Particle Bed Breakage

Crystalline graphite,used widely because of its excellent physical,chemical and mechanical properties,is one of the indispensable non-metallic materials in today’s global high-tech development.With the rapid development of new energy,new materials and other strategic emerging industries,the quality of graphite raw materials is also put forward higher requirements.At present,there are many problems in the industrial production of crystalline graphite,such as backward technology,low concentrate index and low yield of large scale.Based on the particle bed breakage principle,this study proposed that applying HPGR to rough grinding operation of flake graphite raw ore instead of BM firstly,and developed the new technology of "fine classification-regrinding and floation distinctively"of crystalline graphite.This research analyzed the difference of particle size composition and floatability between products milled by HPGR&BM.Finally,the comparative study of flotation experiments tests was carried out using the "particle bed breakage-fine classification-regrinding and floation distinctively" technology and the conventional stage grinding-floation technology on crystalline graphite in Luobei,Heilongjiang province,to providing theoretical support for the application and promotion of this innovative technology.Mineralogy study means that the useful mineral in the sample is graphite,thefixed carbon content is 13.39%,gangue mineral is quartz,potassium feldspar,mica,limonite mainly.Most of the scales were in the form of autoloblastic lamellar crystals with weakly oriented arrangement.The mosaic size was coarse relatively,and the grain grade content of+0.147mm reached 68.78%.However,most of the coarse-grained grains were obviously twisted.And gangue minerals embedded complex,most of the graphite and mica closely symbiosis,showing mutual wrapped or interlayer distribution;The graphite interlayer is mixed with feldspar,quartz and other granular minerals or wrapped by the latter,so it is difficult to grind and dissociate,and the scale structure is easily destroyed in the process of grinding and dissociation.With the same fineness,the HPGR products have smaller average grain size,which is concentrated in-0.044mm and-0.180+0.17mm grain size,compared with BM products.The fixed carbon content of flotation rough concentrate of HPGR products was increased by about 5 percentage points,the recovery rate was increased by about two percentage points,and the degree of dissociation of laminate products was higher.The study on the properties of coarse concentrate milled by stirred grinding shows that it takes less time to reach the same degree of fineness.When the regrinding fineness is lower,the grinding efficiency of HPGR products is higher,and when the fineness rises to a certain value,the grinding efficiency of BM products is higher.It shows that HPGR products are grindable,easier to be ground,and the phenomenon of grinding will occur if the grinding time is too long.The grinding kinetics of vertical flake stripper shows that the whole grain grinding of crystalline graphite can be divided into two processes:rapid grinding of large scale and dynamic grinding of fine scale.The microscale did not enter the effective grinding and disintegration state until almost all the macroscale was crushed,indicating that there were problems of overgrinding of macroscale and insufficient grinding of microscale in the whole grain grinding process of crystalline graphite.Based on the above research,the technology of crystalline graphite "particle bed breakage-fine classification-regrinding and floation distinctively" technology is proposed,which can protect the flake and weaken the over-grinding effect by changing the grinding process of raw ore and the floating environment of coarse concentrate grinding.By "fine classification " process of the coarse concentrate of the flotation of HPGR products,two kinds of products were obtained.The+0.147mm size fraction concent of coarse products with low F.C is 73.24%,the fixed carbon content is 18.15%,and the degree of dissociation was lower.The+0.147mm size fraction concent of fine products with high F.C is 17.16%,the fixed carbon content is 66.13%,the dissociation is better,scattered fine gangue minerals the surface.There are obvious differences in particle size composition,mineral composition,degree of dissociation and floatability.The results of closed-circuit flotation experiment shows that the fixed carbon content of 94.51%,recovery rate of 89.91%and+0.147mm size fraction distribution rate of 31.70%of concentrate product obtained using "particle bed breakage-fine classification-regrinding and floation distinctively"technology,and the fixed carbon content of 94.04%,recovery rate of 90.66%and+0.147mm size fraction distribution rate of 17.26%of concentrate product obtained using traditional process technology.Most of the new technology concentrate products have complete scale structure,round edges,thick flake layers and rich cracks,which will definitely have a beneficial effect on the properties of downstream deep processing materials.No matter in the concentrate index,or in the micro morphology and structure of the large scale,the technology of "particle bed breakage-fine classification-regrinding and floation distinctively" is better than the separation result of the conventional process.