Slowly soluble ammonium polyphosphate and method for its manufacture

Claim 1

IN A PROCESS FOR PRODUCING A HIGH-ANALYSIS AMMONIUM POLYPHOSPHATE FERTILIZER MATERIAL FROM ANHYDROUS AMMONIA AND HIGHLY CONCENTRATED SUPERPHOSPHORIC ACID, WHEREIN IS MAINTAINED IN A CLOSED REACTION VESSEL AT A TEMPERATURE IN THE RANGE FROM ABOUT 300*F TO ABOUT 600*F AND UNDER A CONSTANT PRESSURE IN THE RANGE OF ABOUT 10 P.S.I.G TO ABOUT 1000 P.S.I.G. A MASS OF MOLTEN MATERIAL OF LOW VISCOSITY PREVIOUSLY FORMED BY COMBING SUCH MATERIALS ARE CONTINUOUSLY COMBINED INTO SAID MASS AND SAID MASS IS CONTINUOUSLY SUBJECTED TO VIGOROUS AGITATION,THEREBY KEEPING SUBSTANTIALLY THE ENTIRE MASS AGITATED AND EFFECTING IMMEDIATE AMMONIATION OF SAID INFLOWING ACID, AND WHEREIN A MASS OF SURPLUS MOLTEN AMMONIUM PHOSPHATE MATERIAL IS WITHDRAWN FROM THE LOWER PORTION OF SAID REACTION VESSEL, THE IMPROVEMENT THEREIN WHICH COMPRISES THE MANUFACTURE OF A HIGH-ANALYSIS, SLOWLY SOLUBLE AMMONIUM POLYPHOSPHATE MATERIAL FROM ANHYDROUS AMMONIA AND SUPERPHOSPHORIC ACID, SAID SUPERPHOSPHORIC ACID HAVING A MINIMUM CONCENTRATION OF 83% P2O5, SAID IMPROVEMENT COMBINING WITH SAID AFOREMENTIONED STEPS THE FOLLOWING STEPS WHICH COMPRISE STATICALLY COOLING SAID SURPLUS MOLTEN AMMONIUM POLYHOSPHATE MATERIAL WITHDRAWN FROM THE LOWER PORTION OF SAID REACTION VESSEL FROM A TEMPERATURE IN THE RANGE OF ABOUT 300*F. TO ABOUT 600*F. DOWN TO A TEMPERATURE IN THE RANGE FROM ABOUT 100*F TO 0*F.; SUBSEQUENTLY CONTACTING THE RESULTING GELATINOUS-LIKE MASS WITH AQUEOUS MEDIUM, THEREBY EFFECTING THE PRECIPITATION OF AN INSOLUBLE LONG-CHAIN AMMONIUM POLYPHOSPHATE SALT; AND RECOVERING AS PRODUCT SAID SALT.