Production of potassium-containing nitrophosphates

Claim 1

IN A PROCESS FOR THE PRODUCTION OF GRANULAR FORM OF POTASSIUM-CONTAINING NITROPHOSPHATES OF LOW WATER CONTENT AND HIGH SOFTENING POINT BY DECOMPOSING PHOSPHATE ROCK WITH AN AMOUNT OF HNO3 THEORETICALLY REQUIRED TO COVERT 80-85% OF THE TOTAL P2O5 OF THE PHOSPHATE ROCK TO WATER SOLUBLE FORM AND TO OBTAIN PRODUCTS WITH AT MOST 2-3 MOLS OF WATER OF CRYSTALLIZATION PER MOL OF CALCIUM NITRATE, BY ADDING POTASSIUM SULPHATE, KNEADING THE MIXTURE AND COVERTING THE HOT DOUGHY MASS BY COOLING AND HARDENING INTO GRANULAR FORM; THE IMPROVEMENT COMPRISING THE STEPS OF KNEADING SAID DECOMPOSITION MASS INTENSIVELY UNTIL THE CONTENT OF FREE ACID IN THE MASS IS BELOW 3%, ADDING TO SAID MASS A QUANTITY OF POTASSIUM SULPHATE WHEREBY THE MIXED PRODUCT CONTAINS 5-14% K2O, AND INTENSIVELY KNEADING SAID MIXED PRODUCT AT A TEMPERATURE OF AT LEAST 80* C.