Meaning: The pre deshaling in dry coal preparation will remove a large amount of reject in advance, reduce the amount of reject entering the heavy medium system, reduce equipment wear and reduce operating costs; Reduce the content of high ash fine mud in the water washing system, and improve the separation accuracy of the heavy medium system. It can also avoid the influence of the primary slime produced by washing and discharging reject and the secondary slime produced by sliming reject on the flotation effect, optimize the flotation effect and improve the total clean coal recovery.
Effect: According to the different conditions of coking coal entering and washing, the reject removal rate of coal with grain size can reach more than 80%, and the coal carried in the reject (- 1.8g/cm3) is less than 1%. The recovery rate of the pre discharged reject in dry coal washing is 1~2% higher than that of the cleaned coal directly entering and washing.
