The granulation rate of the rotary drum granulator is 70%, the average granulation strength is>10N, the product nutrients are uniform, and the adaptability is strong. Steam can be introduced into the machine, and phosphoric acid or ammonia solution, slurry, etc. can also be added to complete the chemical reaction in the cylinder for the production process of compound fertilizer; It can also be used in the production process of compound fertilizers to supplement moisture and increase humidity.