Henan Province is a coal rich province with abundant coal resources. The inconsistent control of separation density in the separation process of coal washing equipment leads to differences in boundary ash content, resulting in low clean coal production and total amount. The ash content of the same density in different separation stages of coal washing equipment should be controlled within the same or similar range as much as possible to obtain the best production indicators. Practice has proven that the ash content of coal washing machine flotation clean coal should be appropriately reduced and stabilized at around 12 ^. Do not overly emphasize the improvement of the ash content of flotation tail coal, it can be appropriately stabilized at around 45 ^; If the above separation conditions are met, the total ash content can basically reach over 60% of the clean coal production. To determine reasonable sorting conditions and optimal production indicators, it is necessary to master comprehensive and detailed production data, conduct in-depth analysis and production practice verification.

　　According to the analysis of the raw coal situation, -1.3 and 1.4 are the main density grades, and -1.4 density grade accounts for 50% of the raw coal. This part of coal has a relatively low ash content and is the main component of clean coal. The total clean coal yield and quantity efficiency of coal preparation equipment also depend on the recovery rate of this part of coal. The physical separation density is close to 1.6, while the highest separation density used by the main washing jig is 1.47. However, the ash content of clean coal is not the highest because reducing the separation density reduces the low-density and high-density parts recovered into clean coal. In terms of quantity, the low-density part is much smaller than the high-density part, so the high-density part of clean coal in the coal preparation equipment is relatively increased, which is also the reason for the increase in clean coal ash content after reducing the sorting density.