Manufacture of caustic soda granules

Claim 1

A PROCESS FOR THE PRODUCTION OF CAUSTIC SODA IN THE FORM OF GRANULES HAVING A WATER CONTENT LESS THAN 0.5% BY WEIGHT WHICH COMPRISES SPRAYING AN AQUEOUS SOLUTION CONTAINING BETWEEN 80 AND 95% BY WEIGHT OF NAOH HAVING A TEMPERATURE BETWEEN 200* AND 300* C. INTO A CONFINED ZONE UPWARDLY THROUGH WHICH A CURRENT OF SUBSTANTIALLY NON-HEAT SUPPLYING INERT GAS IS PASSED, ALLOWING THE DROPLETS OF SPRAYED SOLUTION TO FORM GRANULES OF SOLID CAUSTIC SODA BY CONTACT WITH SAID GAS CURRENT, ACCUMULATING THE RESULTING GRANULES AS A BED, THE SAID SPRAY BEING POSITIONED A DISTANCE ABOVE THE SAID BED SO THAT HAVING REGARD TO THE SIZE OF THE SPRAY DROPLETS, THE DEPTH OF FALL THROUGH THE CONFINED ZONE, AND THE DIRECTION OF THE SPRAY, THE SPRAY DROPLETS ARE DRIED TO FORM SUPERFICIALLY DRY GRANULES WHEN THEY LAND ON THE BED, PASSING THE SAID CURRENT OF DRY GAS UP THROUGH SAID BED AT A VELOCITY WHICH MAINTAINS THE GRANULES IN A FLUIDISED STATE AND WITHDRAWING GRANULES FROM SAID BED.