The steam enters the heating pipe through the distribution chamber, while a small amount of wet gas is heated by the heater and enters the cylinder. The heat exchange tube in the cylinder body rotates with the cylinder, and the wet material and the returned dry material are mixed by the spiral feeder and added to the cylinder. The material entering the dryer is lifted and stirred by the heat exchange tube in the cylinder body, and is dried by the heat provided by the heat exchange tube. The dried product moves by the inclination of the dryer and is discharged from the discharge port located at the lower end, and is lifted by the bucket elevator after passing the screening by the vibrating screen. Part of the product is returned as the material, and the rest enters the powder flow cooling and is sent to the bin or packaging system after the cooling is completed. The wet gas containing evaporating water and a small amount of dust is discharged into the dust removal system through the exhaust port. After purification and dust removal, it is discharged by the induced draft fan to meet the standards.