Abstract: To solve the problems of long settling time of coal slurry and high dosage of flotation agent Halagou coal preparation plant,added the SK static mixer into the feeding pipeline of thickening poor, and described the structure,mixing principle and technical parameters of mixer. With the utilizing of the mixer reduced the consumption of the agent,higher the processing capacity of the thickening poor and increased the washed rate of the small coal,which created the better economic benefit for the coal preparation plant.