Method of rapid differential flocculation of tio{11 from kaolin slurries

Claim 1

A METHOD OF BENEFICIATING KAOLIN CLAY CONSISTING ESSENTIALLY OF THE STEPS OF: A. TREATING AN AQUEOUS KAOLIN CLAY SUSPENSION OF FROM 45 TO 70 PERCENT SOLIDS BY WEIGHT WITH A DISPERSING AGENT IN AN AMOUNT IN EXCESS OF THAT REQUIRED TO OBTAIN MINIMUM VISCOSITY, SAID DISPERSING AGENT COMPRISING THE CMBINATION OF SODIUM HEXAMETAPHOSPHATE AND SODIUM SILICATE; CONTINUING THE ADDITION OF SAID SODIUM HEXAMETAPHOSPHATE AND SAID SODIUM SILICATE TO EFFECT REFLOCCULATION OF SAID AQUEOUS KAOLIN CLAY SUSPENSION; THE COMBINED AMOUNT OF SAID SODIUM HEXAMETHAPHOSPHATE AND SAID SODIUM SILICATE BEING ADDED TO SAID AQUEOUS SUSPENSION COMPRISING FROM 2 TO 10 POUNDS PER TON OF DRY CLAY OF SODIUM HEXAMETAPHOSPHATE AND FROM 8 TO 20 POUNDS PER TON OF DRY CLAY OD SODIUM METASILICATE SO AS TO OBTAIN SAID MINIMUM VISCOSITY AND REFLOCCULATION BUT CMPRISING AN AMOUNT LESS THAN WHICH PRODUCES AN INTRACTABLE GEL STATE; B. DILUTING SAID REFLOCCULATED SLURRY TO FROM 25 TO 45 PERCENT SOLIDS; C. TREATING SAID SLURRY BY ADDING TO IT FROM 4 TO 50 POUNDS PER TON OF DRY CLAY OF SODIUM CHLORIDE; D. AGING SAID SALT TREATED SLURRY FOR FROM 1 TO 24 HOURS; E. FURTHER DILUTING SAID AGED SLURRY TO FROM 10 TO 35 PERCENT SOLIDS; F. ADDING TO AND MIXING WITHIN SAID DILUTED AGED SLURRY FROM 0.01 TO 0.3 POUNDS PER TON OF DRY CLAY OF A WATER SOLUBLE, STRONGLY ANIONIC POLYACRYLAMIDE POLYMER HAVING A MOLECULAR WEIGHT IN EXCESS OF ONE MILLION, WHEREBY A SEPARATION OF TITANIUM-POLYMER FFLOCS IS EFFECTED FROM SAID SUSPENSION AT A SEDIMENTATION RATE IN EXCESS OF 10 MINUTES PER INCH OF DEPTH OF SAID SLURRY, AND G. SEPARATING THE THUS REFINED SLURRY FROM SAID FLOCS.

Claim 2

A METHOD OF BENEFICIATING KAOLIN CLAY CONSISTING ESSENTIALLY OF THE STEPS OF: A. TREATING AN AQUEOUS KAOLIN CLAY SUSPENSION OF FROM 45 TO 70 PERCENT SOLIDS BY WEIGHT WITH A DISPERSING AGENT IN AN AMOUNT IN EXCESS OF THAT REQUIRED TO OBTAIN MINIMUM VISCOSITY, SAID DISPERSING AGENT COMPRISING THE CMBINATION OF SODIUM HEXAMETAPHOSPHATE AND SODIUM SILICATE; CONTINUING THE ADDITION OF SAID SODIUM HEXAMETAPHOSPHATE AND SAID SODIUM SILICATE TO EFFECT REFLOCCULATION OF SAID AQUEOUS KAOLIN CLAY SUSPENSION; THE COMBINED AMOUNT OF SAID SODIUM HEXAMETHAPHOSPHATE AND SAID SODIUM SILICATE BEING ADDED TO SAID AQUEOUS SUSPENSION COMPRISING FROM 2 TO 10 POUNDS PER TON OF DRY CLAY OF SODIUM HEXAMETAPHOSPHATE AND FROM 8 TO 20 POUNDS PER TON OF DRY CLAY OD SODIUM METASILICATE SO AS TO OBTAIN SAID MINIMUM VISCOSITY AND REFLOCCULATION BUT CMPRISING AN AMOUNT LESS THAN WHICH PRODUCES AN INTRACTABLE GEL STATE; B. DILUTING SAID REFLOCCULATED SLURRY TO FROM 25 TO 45 PERCENT SOLIDS; C. TREATING SAID SLURRY BY ADDING TO IT FROM 4 TO 50 POUNDS PER TON OF DRY CLAY OF SODIUM CHLORIDE; D. AGING SAID SALT TREATED SLURRY FOR FROM 1 TO 24 HOURS; E. FURTHER DILUTING SAID AGED SLURRY TO FROM 10 TO 35 PERCENT SOLIDS; F. ADDING TO AND MIXING WITHIN SAID DILUTED AGED SLURRY FROM 0.01 TO 0.3 POUNDS PER TON OF DRY CLAY OF A WATER SOLUBLE, STRONGLY ANIONIC POLYACRYLAMIDE POLYMER HAVING A MOLECULAR WEIGHT IN EXCESS OF ONE MILLION, WHEREBY A SEPARATION OF TITANIUM-POLYMER FFLOCS IS EFFECTED FROM SAID SUSPENSION AT A SEDIMENTATION RATE IN EXCESS OF 10 MINUTES PER INCH OF DEPTH OF SAID SLURRY, AND G. SEPARATING THE THUS REFINED SLURRY FROM SAID FLOCS.