Considering that the clay content in the western Liaoning region is high, the dominant fraction is <0.045 mm high ash in fine-grained low thermal coal and coal slurry. Self-developed CMC (Cone type Multi-stage Cyclone) multiple multistage small cone angle hydrocyclone groups are used for desliming flotation experiment research, product particle size analysis, hydrocyclone underflow product order evaluation tests and flotability evaluation. The results showed that 150 mm hydrocyclones with small cone angles are more suitable as the main desliming equipment before flotation than those with 75 mm and 50 mm hydrocyclones with small cone angles, but the bottom abortion rate is lower, and the phenomenon of “overflow running” is more serious. In the deslime-flotation process of the CMC multistage and small-cone angle hydrocyclone groups, the removal rate of fine particles with ash contents of 69.82% <0.045 mm in the original coal slime reaches 64.43%, basically solved the problem of “overflow and coarse running” of cyclones, and high ash fine clay minerals such as kaolin were enriched in the overflow. The group of three kinds of CMC hydrocyclone underflow products due to their different size widths shows that the flotability of the three underflows can be mixed into the float. Compared with raw coal direct flotation plants, the yield and combustible recovery rate can increase 2-3 times, and the floatability level is increased from extremely difficult to float to difficult to float, which can also be used for the underflow product floatability. The flotation process is different, strengthening the graded plant recycling process and providing a technological reference for better realization of narrows lime flotation.