Granulated nitrogen-phosphorus-potassium-sulfur fertilizer from waste gypsum slurry

摘要

Process for converting phospho-gypsum waste product from the wet process of manufacturing phosphoric acid from phosphate rock by ammoniating said product at a pH of 6.5 or less and adjusting the phosphorus and potassium values of said ammoniated product by addition of one or more sources of potassium and phosphorus.