Abstract: A high cost is incurred due to the high consumption of filter aids in Heilonggou Coal Preparation Plant.Coal slime size analysis shows this is attributable to the presence of high proportion of high-ash fine particles and refuse particles in coal slime.In order to reduce the cost incurred, multiple measures such as the use of automatic agent dosing system, change of inclination angle of belt conveyor, use of new agent, and change of size consist of slime feed to filter press.Through adoption of the measures, in the instance that the feeding time of filter press remains unchanged, the consumption of filter aid is reduced by 180 g/t, and when the dosage of the agent remains unchanged, the time required for feeding the filter press is shortened by 900 seconds.This makes it possible for the plant to increase the capacity of filter press by over 30%, curtail the unit price of agent by 34.06% and realize a save of operating cost of 2.40 million yuan per year.