Method for comminuting kaolin clay

Claim 1

A METHOS FOR REDUCING THE PARTICLE SIZE OF KAOLIN CLAY WHICH COMPRISES AGITATING KAOLIN CLAY IN WATER CONTAINING A DEFLOCCULATING AGENT SO AS TO OBTAIN AN AQUEOUS DISPERSION OF KAOLIN CLAY, INCORPORATING INTO SAID DISPERSION -10 +35 MESH PARTICLES OF SILICA SAND AS A GRINDING MEDIUM IN AMOUNT TO EXCEED SUBSTANTIALLY THE WEIGHT OF SAID CLAY,PARTIALLY FILLING AN AGITATOR-FREE DRUM HAVING A SMOOTH INNER SURFACE WITH SAID DISPERSION AND SAID SAND, SUBJECTING SAID CLAY TO A GRINDING ACTION WITH A LOW ENERGY EXPENDITURE AND WITHOUT GRINDING SAID SAND BY CONTINUOUSLY ROTATING SAID DRUM WITH SAID SLIP AND SAID SAND WITH THE DRUM DISPOSED IN A MANNER SUCH THAT THE LONGITUDINAL AXIS OF SAID DRUM IS IN HORIZONTAL PLANE AT A PERIPHERAL VELOCITY WITHIN THE RANGE OF ABOUT 200 TO ABOUT 300 FEET PER MINUTE, SAID VELOCITY BEING LESS THAN CRITICAL SPEED FOR SAID DRUM, FOR A TIME SUFFICIENT TO REDUCE SUBSTNATIALLY THE ULTIMATE PARTICLE SIZE OF SAID CLAY, AND SEPARATING SAID SAND FROM THE CLAY DISPERSION.