Continuous method for the manufacture of ammonium chloride

Claim 1

A METHOD FOR PRODUCING (1) AMMONIUM CHLORIDE CRYSTALS SUBSTANTIALLY FREE FROM SODIUM CHLORIDE AND (2) A LIQUOR SATURATED WITH SODIUM CHLORIDE, FROM THE SODIUM BICARBONATE MOTHER LIQUOR OF THE AMMONIA-SODA PROCESS, FROM WHICH MOTHER LIQUOR SOLID SODIUM BICARBONATE HAS BEEN REMOVED, COMPRISING: (A) ADDING A MIXTURE OF LARGER AND SMALLER SIZED SODIUM CHLORIDE CRYSTALS HAVING PARTICLE SIZED WITHIN THE RANGE OF 20 TO 100 MESH, A SUBSTANTIAL PORTION OF WHICH HAS PARTICLE SIZED LARGER THAN 40 MESH AND ANOTHER SUBSTANTIAL PORTION OF WHICH HAS PARTICLE SIZES SMALLER THAN 50 MESH IN EXCESS ABOVE THE AMOUNT REQUIRED FOR SATURATION WITH NACI, TO THE SAID SODIUM BICARBONATE MOTHER LIQUOR WHILE STIRRING AND COOLING THE SAME TO A TEMPERATURE SUFFICIENTLY LOW TO OBTAIN AMMONIUM CHLORIDE IN FLOCCULENT FROM THEREIN; (B) CONVEYING THE RESULTING SLURRY TOWARD A SEPARATION ZONE AND A FLOW RATE SUFFICIENT TO MAINTAIN SAID AMMONIUM CHLORIDE OF FLOCCULENT FORM AS WELL AS THE SMALLER SIZED SODIUM CHLORIDE CYRSTALS THEREIN IN SAID SLURRY AND SIMULTANEOUSLY APPLYING SEDIMENTING FORCES THERETO, THEREBY REMOVING ESSENTIALLY ONLY THE LARGER SIZED SODIUM CHLORIDE PARTICLES FROM SAID SLURRY, AND (C) SUBJECTING THE RESULTING SLURRY FREE FROM LARGERSIZED SODIUM CHLORIDE CRYSTALS TO FURTHER COOLING IN SAID SEPARATION ZONE AT A TEMPERATURE DECREASING THROUGHOUT THE LENGTH OF SAID ZONE BY ABOUT 2 TO 5 DEGREES CENTIGRADE BELOW THE TEMPERATURE PREVAILING AT STEP (B) UNTIL ALL SMALLER SIZED SODIUM CHLORIDE CRYSTALS ARE COMPLETELY DISSOLVED, THEREBY SATURATING THE LIQUID PART OF SAID SLURRY WITH NACI AT SAID LOWER TEMPERATURE WHILE PRECIPITATING SAID AMMONIUM CHLORIDE IN THE FORM OF SEPARABLE CRYSTALS SUBSTANTIALLY FREE FROM SODIUM CHLORIDE, AND (D) SEPARATING THE AMMONIUM CHLORIDE CRYSTALS FROM SAID SODIUM CHLORIDE-SATURATED LIQUOR.

Claim 2

A METHOD FOR PRODUCING (1) AMMONIUM CHLORIDE CRYSTALS SUBSTANTIALLY FREE FROM SODIUM CHLORIDE AND (2) A LIQUOR SATURATED WITH SODIUM CHLORIDE, FROM THE SODIUM BICARBONATE MOTHER LIQUOR OF THE AMMONIA-SODA PROCESS, FROM WHICH MOTHER LIQUOR SOLID SODIUM BICARBONATE HAS BEEN REMOVED, COMPRISING: (A) ADDING A MIXTURE OF LARGER AND SMALLER SIZED SODIUM CHLORIDE CRYSTALS HAVING PARTICLE SIZED WITHIN THE RANGE OF 20 TO 100 MESH, A SUBSTANTIAL PORTION OF WHICH HAS PARTICLE SIZED LARGER THAN 40 MESH AND ANOTHER SUBSTANTIAL PORTION OF WHICH HAS PARTICLE SIZES SMALLER THAN 50 MESH IN EXCESS ABOVE THE AMOUNT REQUIRED FOR SATURATION WITH NACI, TO THE SAID SODIUM BICARBONATE MOTHER LIQUOR WHILE STIRRING AND COOLING THE SAME TO A TEMPERATURE SUFFICIENTLY LOW TO OBTAIN AMMONIUM CHLORIDE IN FLOCCULENT FROM THEREIN; (B) CONVEYING THE RESULTING SLURRY TOWARD A SEPARATION ZONE AND A FLOW RATE SUFFICIENT TO MAINTAIN SAID AMMONIUM CHLORIDE OF FLOCCULENT FORM AS WELL AS THE SMALLER SIZED SODIUM CHLORIDE CYRSTALS THEREIN IN SAID SLURRY AND SIMULTANEOUSLY APPLYING SEDIMENTING FORCES THERETO, THEREBY REMOVING ESSENTIALLY ONLY THE LARGER SIZED SODIUM CHLORIDE PARTICLES FROM SAID SLURRY, AND (C) SUBJECTING THE RESULTING SLURRY FREE FROM LARGERSIZED SODIUM CHLORIDE CRYSTALS TO FURTHER COOLING IN SAID SEPARATION ZONE AT A TEMPERATURE DECREASING THROUGHOUT THE LENGTH OF SAID ZONE BY ABOUT 2 TO 5 DEGREES CENTIGRADE BELOW THE TEMPERATURE PREVAILING AT STEP (B) UNTIL ALL SMALLER SIZED SODIUM CHLORIDE CRYSTALS ARE COMPLETELY DISSOLVED, THEREBY SATURATING THE LIQUID PART OF SAID SLURRY WITH NACI AT SAID LOWER TEMPERATURE WHILE PRECIPITATING SAID AMMONIUM CHLORIDE IN THE FORM OF SEPARABLE CRYSTALS SUBSTANTIALLY FREE FROM SODIUM CHLORIDE, AND (D) SEPARATING THE AMMONIUM CHLORIDE CRYSTALS FROM SAID SODIUM CHLORIDE-SATURATED LIQUOR.