Research on the Manufacturing of NPK Compound Fertilizer by the Reaction of Potash Feldspar with Phosphorite and Phosphoric Acid

The production of the reaction of potash feldspar with phosphorite and phosphoric acid were leached and neutralized to product the NPK compound fertilizer and slow-released phosphate or to product the both available and slow -released compound fertilizer. The process of leaching the production of the reaction of potash feldspar with phosphorite and phosphoric acid and neutralizing were especially investigated. The results show that, the optimum operation conditions of leaching were confirmed as follow: temperature 70℃, time 100min, water for leaching 10mL/g material. The recovery of potassium and phosphorus can both exceed 84% and 85% when the end point pH of leaching were about 6. The process is simple and the slow -releasing of the production can be controlled so it has good development prospect in fertilizer industry.