Process for obtaining slow release P-K fertilizer with a zeolite base

摘要

Process for obtaining slow release P-K fertilizer with a zeolite base. A process for obtaining fertilizer products charged with phosphorus and potassium from tuffaceous materials of volcanic origin which are rich in ion exchange minerals known as zeolites is described. The process consists in grinding and screening the zeolite material to a particle size of less than 2 mm diameter and treating it with concentrated solutions of orthophosphoric acid in order to remove the exchangeable sodium in the material and increase its porosity. Subsequently the material is washed with water to remove excess acid and again treated with concentrated solutions of monopotassium orthophosphate (KH2PO4). These products can increase the cost/effectiveness ratio of the original fertilizer product.