Concentration op phosphoric acid

Claim 1

A PROCESS FOR THE OBTAINING OF PHOSPHORIC ACIDS OF HIGH P2O5 CONTENT, COMPRISING CONTINUOUSLY FEEDING A WETPROCESS PHOSPHORIC ACID SOLUTION TO A HEATING ZONE AND CONTINUOUSLY WITHDRAWING A MORE CONCENTRATED PRODUCT CONTAINING AT LEAST 68% P205 W./W. (IFB) FROM SUCH ZONE WHILE MAINTAINING SUCH PRODUCT AT ITS BOILING POINT IN SAID ZONE BY RELEASING HOT COMBUSTION PRODUCTS INTO THE BODY OF THE PRODUCT IN SAID ZONE; PASSING THE GASEOUS EFFLUENT FROM SUCH ZONE TO A SCRUBBING ZONE TO FLOW THEREIN AT A VELOCITY IN THE RANGE 15 TO 100 FEET PER SECOND; CAUSING SAID EFFLUENT TO FLOW WITH A VELOCITY IN THE RANGE 100 TO 400 FEET PER SECOND WHILE PASSING THROUGH APERTURES IN A BARRIER OBTURATING SAID SCRUBBING ZONE, THEREBY TO EFFECT A PRESSURE DROP NOT LESS THAN 15 INCHES WATER GAUGE ACROSS SAID BARRIER; PROJECTING A COARSE SPRAY OF HOT WEAK PHOSPHORIC ACID AT THE UPSTREAM FACE OF SAID BARRIER TO CAUSE LARGE DROPLETS OF SUCH ACID TO BREAK, ON SAID FACE OF THE BARRIER, INTO SMALLER DROPLETS THAT MOVE GENERALLY PARALLEL WITH SAID BARRIER FACE AND INTERCEPT THE EFFLUENT FLOWING THROUGH SAID APERTURES; SEPARATING SAID SPRAYED PHOSPHORIC ACID FROM THE EFFLUENT DOWNSTREAM OF SAID BARRIER; AND THEREAFTER TREATING THE SEPARATED GASEOUS EFFLUENT WITH COLD WATER.