Process for making granular hydrated alkali metal silicate

Claim 1

IN THE PROCESS FOR PRODUCING GRANULES CONSISTING ESSENTIALLY OF A PLURALITY OF HYDRATED AMORPHOUS ALKALI METAL SILICATE PARTUCLES BONDED TOGETHER AT TOUCHING SURFACES, HAVING AN SIO2/M2O MOL RATIO OF 1.2 TO 4.0/1.0. THE IMPROVEMENT WHEREBY SAID PRODUCT IS PRODUCED IN A CONTINUOUS SPRAY DRYING PROCESS WHICH RESULTS IN A PRODUCT HAVING 10 TO 30% EQUILIBRATED MOISTURE AND A TAMPED BULK DENSITY OF 20 TO 55 LBS/CU.FT. COMPRISING: A. MAINTAINING A SPRAY DRYER WITH A GAS INLET TEMPERATURE OF 250* TO 500*F AND GAS OUTLET TEMPERATURE OF 160* TO 250*F, B. INJECTING AN ATOMIZED AQUEOUS ALKALI METAL SILICATE SOLUTION INTO SAID SPRAY DRYER SO THAT APPARENTLY DRY PARTICLES ARE FORMED DURING THE PASSAGE THROUGH THE SPRAY DRYER, C. ENTRAINING SAID PARTICLES IN A GAS FLOWING AT 100 TO 250 FT/MIN, D. CONDUCTING SAID ENTRAINED PARTICLES THROUGH A COLLECTION SYSTEM WHEREIN THE PARTICLES HAVING A PARTICLE SIZE LARGER THAN ABOUT 100 MESH SEPARATE FROM THE FLOWING GAS BY GRAVITY BECAUSE THEY ARE TOO LARGE TO REMAIN ENTRAINED IN SAID GAS FLOW WHILE THE PARTICLES SMALLER THAN 100 MESH REMAIN ENTRAINED IN THE GAS FLOW, E. INJECTING THE GAS FLOW WITH SAID ENTRAINED SMALL PARTICLES SMALLER THAN 100 MESH INTO SPRAY DRYER AT A POINT ABOVE THE INJECTION POINT FOR THE ALKALI METAL SILICATE SOLUTION SO THAT THE FALLING PARTICLES ENCOUNTER SAID ATOMIZED ALKALI METAL SILICATE SOLUTION AND AGGLOMERATES ARE FORMED, AND A. MAINTAINING A SPRAY DRYER WITH A GAS INLET TEMPERATURE OF SOLUTION SUCH THAT THE SOLIDS UNJECTED INTO THE SPRAY DRYER ARE EQUAL TO THE PRODUCT SOLIDS REMOVED IN THE COLLECTION SYSTEM.