Process for concentrating wet-process phosphoric acid

Claim 2

IN AN IMPROVED PROCESS FOR THE PRODUCTION OF A FLUID, HIGHLY CONCENTRATED WET-PROCESS PHOSPHORIC ACID SUBSTANTIALLY FREE OF IRON ALUMINUM TRIPOLYPHOSPHATE, WHICH PROCESS COMPRISES THE STEPS OF CONTINUOUSLY FEEDING COMMERICALLY AVAILABLE WET-PROCESS PHOSPHORIC ACID CONTAINING IN THE RANGE FROM ABOUT 30 PERCENT BY WEIGHT P2O5 TO ABOUT 54 PERCENT BY WEIGHT P2O5 INTO EVAPORATING MEANS; MAINTAINING THE MATERIAL IN SAID EVAPORATING MEANS AT A TEMPERATURE IN THE RANGE OF ABOUT 450*F. TO ABOUT 600*F.; AND WITHDRAWING AS PRODUCT FROM SAID EVAPORATING MEANS A HIGHLY CONCENTRATED FLUID WET-PROCESS PHOSPHORIC ACID SUBSTANTIALLY FREE OF SOLIDS, CONTAINING FROM ABOUT 60 TO 76 WEIGHT PERCENT P2O5 AND CONTAINING IN SOLUTION SUBSTANTIALLY ALL OF THE CONGENERIC IMPURITIES ORIGINALLY PRESENT IN SAID COMMERCIALLY AVAILABLE WET-PROCESS PHOSPHORIC ACID FED TO SAID EVAPORATING MEANS, THE IMPROVEMENT IN COMBINATION THEREWITH FOR PREVENTING THE FORMATION OF THE ACID INSOLUBLE UNDESIRABLE SALTS OF IRON ALUMINUM TRIPOLYPHOSPHATE IN THE RESULTING CONCENTRATED WET-PROCESS PHOSPHORIC ACID, WHICH IMPROVED PROCESS COMPRISES THE ADDITIONAL STEP OF RETAINING IN SAID EVAPORATING MEANS FOR A PERIOD OF TIME FROM ABOUT 1 MINUTE BUT LESS THAN ABOUT 20 MINUTES THE WET-PROCESS PHOSPHORIC ACID BEING CONCENTRATED THEREIN PRIOR TO WITHDRAWING SAME AS PRODUCT FROM SAID EVAPORATING MEANS.

Claim 3

IN AN IMPROVED PROCESS FOR THE PRODUCTION OF A HIGH-ANALYSIS, LIQUID MIXED FERTILIZER SUBSTANTIALLY FREE OF IRON ALUMINUM TRIPOLYPHOSPHATE, WHICH PROCESS COMPRISES THE STEPS OF CONTINUOUSLY FEEDING COMMERCIALLY AVAILABLE WET-PROCESS PHOSPHORIC ACID CONTAINING IN THE RANGE FROM ABOUT 30 PERCENT BY WEIGHT P2O5 TO ABOUT 54 WEIGHT PERCENT P2O5 INTO EVAPORATING MEANS; MAINTAINING THE MATERIAL IN SAID EVAPORATING MEANS AT A TEMPERATURE IN THE RANGE OF ABOUT 450*F. TO ABOUT 600*F.; WITHDRAWING FROM SAID EVAPORATING MEANS A HIGHLY CONCENTRATED FLUID WET-PROCESS PHOSPHORIC ACID SUBSTANTIALLY FREE OF SOLIDS, CONTAINING ABOUT 60 TO 76 WEIGHT PERCENT P2O5, AND CONTAINING IN SOLUTION SUBSTANTIALLY ALL OF THE CONGENERIC IMPURITIES ORIGINALLY PRESENT IN SAID COMMERCIALLY AVAILABLE WET-PROCESS PHOSPHORIC ACID FED TO SAID EVAPORATING MEANS; SUBSEQUENTLY INTRODUCING AN AMMONIATING FLUID TO SAID HIGHLY CONCENTRATED PHOSPHORIC ACID; MAINTAINING THE RESULTING SOLUTION OF UNHYDROLYZED AMMONIUM SALTS AT A TEMPERATURE IN THE RANGE OF ABOUT 180*F. TO ABOUT 210*F. DURING INTRODUCTION OF SAID AMMONIATING FLUID; AND WITHDRAWING THE RESULTING SOLUTION AS PRODUCT, THE IMPROVEMENT IN COMBINATION THEREWITH FOR PREVENTING THE FORMATION OF THE ACID INSOLUBLE UNDESIRABLE SALTS OF IRON ALUMINUM TRIPOLYPHOSPHATE IN THE RESULTING CONCENTRATED WET-PROCESS PHOSPHORIC ACID, WHICH IMPROVED PROCESS COMPRISES THE ADDITIONAL STEP OF RETAINING IN SAID EVAPORATING MEANS FOR A PERIOD OF TIME FROM ABOUT 1 MINUTE BUT LESS THAN ABOUT 20 MINUTES THE WET-PROCESS ACID BEING CONCENTRATED THEREIN PRIOR TO WITHDRAWING SAME AS PRODUCT FROM SAID EVAPORATING MEANS.

Claim 4

IN AN IMPROVED PROCESS FOR THE PRODUCTION OF A HIGH-ANALYSIS, LIQUID MIXED FERTILIZER SUBSTANTIALLY FREE OF IRON ALUMINUM TRIPOLYPHOSPHATE, WHICH PROCESS COMPRISES THE STEPS OF CONTINUOUSLY FEEDING COMMERCIALLY AVAILABLE WET-PROCESS PHOSPHORIC ACID CONTAINING IN THE RANGE FROM ABOUT 30 PERCENT BY WEIGHT P2O5 TO ABOUT 54 WEIGHT PERCENT P2O5 INTO EVAPORATING MEANS; MAINTAINING THE MATERIAL IN SAID EVAPORATING MEANS AT A TEMPERATURE IN THE RANGE OF ABOUT 450*F. TO ABOUT 600*F.; WITHDRAWING FROM SAID EVAPORATING MEANS A HIGHLY CONCENTRATED FLUID WET-PROCESS PHOSPHORIC ACID SUBSTANTIALLY FREE OF SOLIDS, CONTAINING ABOUT 60 TO 76 WEIGHT PERCENT P2O5, AND CONTAINING IN SOLUTION SUBSTANTIALLY ALL OF THE CONGENERIC IMPURITIES ORIGINALLY PRESENT IN SAID COMMERCIALLY AVAILABLE WET-PROCESS PHOSPHORIC ACID FED TO SAID EVAPORATING MEANS; SUBSEQUENTLY INTRODUCING AN AMMONIATING FLUID TO SAID HIGHLY CONCENTRATED PHOSPHORIC ACID; MAINTAINING THE RESULTING SOLUTION OF UNHYDROLYZED AMMONIUM SALTS AT A TEMPERATURE IN THE RANGE OF ABOUT 180*F. TO ABOUT 210*F. DURING INTRODUCTION OF SAID AMMONIATING FLUID; AND WITHDRAWING THE RESULTING SOLUTION AS PRODUCT, THE IMPROVEMENT IN COMBINATION THEREWITH FOR PREVENTING THE FORMATION OF THE ACID INSOLUBLE UNDESIRABLE SALTS OF IRON ALUMINUM TRIPOLYPHOSPHATE IN THE RESULTING CONCENTRATED WET-PROCESS PHOSPHORIC ACID, WHICH IMPROVED PROCESS COMPRISES THE ADDITIONAL STEP OF RETAINING IN SAID EVAPORATING MEANS FOR A PERIOD OF TIME FROM ABOUT 1 MINUTE BUT LESS THAN ABOUT 20 MINUTES THE WET-PROCESS ACID BEING CONCENTRATED THEREIN PRIOR TO WITHDRAWING SAME AS PRODUCT FROM SAID EVAPORATING MEANS.