Rotary drum granulator is the preferred fertilizer granulator machine for the production of high-concentration compound fertilizer. The quality of compound fertilizer treated by NPK fertilizer production plant has been significantly improved. Drum granulator machine is suitable for large-scale production of cold & hot compound fertilizer granulation line and high and low concentration NPK fertilizer production process. It play a important role in complex fertilizer processing. The fertilizer has good water solubility, round, smooth granules and high compressive strength. After drying, the water content is low, and the anti-caking ability of the product has been improved.