Abstract: Kailuan coking coal mud area is a typically difficult floated slime.Over years,the recovery of combustible ash flotation is slightly loco and so is the ash content in tailing coal flotation,which results in high quality scarce resources run off.In this paper,through the physical property analysis of the selected slime,the mineral liberation method is used to explore the effect of the grinding process on the flotation of coal slime.Seek new ways of releasing scare resources and improving the recovery of coal flotation concentrate.By a series of modern analytical methods,such as IR,diffraction and scanning clestron microsopy,the study gets some discoveries as follows:the metamorphism of the flotation slurry is not deep and the main content in coal are mineral jmpurities like kadinite and quartz;coal particles take on a scattering distribution and there are a great deal of fine clay minerals on particles'surface and fractures,among which higher surface is liable to competitive adsorption with coal,which can lead to refractory slurry.Combining those basic tests like screening and drifting and so on,the study gets that:the density of the middle part is higher;Coal and mineral impurities are usually in the form of intergrowth.When prefabricated fine ash gets to 12%,the coal slurry is categotized into medium floating.Test results show that the combustible recovery rate of middings coal grinding flotation was 77.85%,ash 12.50%.Compared with the raw coal grinding flotation,the recovery rate was increased by 5.13%,Compared with the direct flotation of raw coal,the recovery rate was increased by 8.23%,which is efficient to improve the resource utilization.