Extrusion granulation is a relatively new dry granulation process for producing compound fertilizers. Extrusion granulation is used in the granulation of potassium chloride in the field of fertilizers. The granular (1-4mm) potassium chloride required for blending fertilizers (BB fertilizer) is basically produced by extrusion. In recent years, extrusion granulation for the production of compound fertilizers has developed rapidly in China.