Alumina particles and method of preparation

Claim 1

THE METHOD OF PREPARING DISCRETE, COHERENT, SPHEROIDAL AGGREGATES OF ALUMINUM TRIHYDROXIDE HAVING AN AVERAGE DIAMETER IN THE RANGE OF ABOUT 0.5-5.0 MM. COMPRISING THE STEPS OF: (A) ADMIXING POWDERED ALUMINUM TRIHYDROXIDE AND AN AQUEOUS MINERAL ACID HAVING A CONCENTRATION OF FROM 15-60% ACID FOR A PERIOD OF ABOUT 25 MINUTES, SAID ACID HAVING BEEN TOTALLY ADDED TO SAID TRIHYDROXIDE DURING THE INITIAL HALF OF SAID TIME PERIOD, THE AMOUNT OF ACID ADDED BEING STOICHIOMETRICALLY SUFFICIENT TO REACT WITH ONLY ABOUT 4-5% OF SAID ALUMINUM TRIHYDROXIDE, (B) AGING THE MASS FORMED IN STEP (A) FOR A PERIOD OF AT LEAST TWO HOURS, UNDER CONDITIONS WHICH MINIMIZE CHANGES IN ITS MOISTURE CONTENT, TO PERMIT COMPLETION OF THE REACTION BETWEEN SAID TRIHYDROXIDE AND SAID ACID, (C) DEAGGREGATING SAID CRUMBLY MASS INT DISCRETE COHERENT PARTICLES, HAVING A SIZE RANGE SUBSTANTIALLY SMALLER THAN THE SIZE RANGE OF THE DESIRED END PRODUCT, AND (D) ROLLING SAID DISCRETE PARTICLES INTO LARGE COHERENT SPHEROIDAL AGGREGATES, HAVING SUFFICIENT STRUCTURAL STRENGTH TO WITHSTAND FURTHER HANDLING AND PROCESSING, SAID ROLLING BEING ACCOMPLISHED WITHOUT THE APPLICATION OF LARGE PARTICLE-TO-PARTICLE CONTACT PRESSURES.

Claim 2

THE METHOD OF PREPARING DISCRETE, COHERENT, SPHEROIDAL AGGREGATES OF ALUMINUM TRIHYDROXIDE HAVING AN AVERAGE DIAMETER IN THE RANGE OF ABOUT 0.5-5.0 MM. COMPRISING THE STEPS OF: (A) ADMIXING POWDERED ALUMINUM TRIHYDROXIDE AND AN AQUEOUS MINERAL ACID HAVING A CONCENTRATION OF FROM 15-60% ACID FOR A PERIOD OF ABOUT 25 MINUTES, SAID ACID HAVING BEEN TOTALLY ADDED TO SAID TRIHYDROXIDE DURING THE INITIAL HALF OF SAID TIME PERIOD, THE AMOUNT OF ACID ADDED BEING STOICHIOMETRICALLY SUFFICIENT TO REACT WITH ONLY ABOUT 4-5% OF SAID ALUMINUM TRIHYDROXIDE, (B) AGING THE MASS FORMED IN STEP (A) FOR A PERIOD OF AT LEAST TWO HOURS, UNDER CONDITIONS WHICH MINIMIZE CHANGES IN ITS MOISTURE CONTENT, TO PERMIT COMPLETION OF THE REACTION BETWEEN SAID TRIHYDROXIDE AND SAID ACID, (C) DEAGGREGATING SAID CRUMBLY MASS INT DISCRETE COHERENT PARTICLES, HAVING A SIZE RANGE SUBSTANTIALLY SMALLER THAN THE SIZE RANGE OF THE DESIRED END PRODUCT, AND (D) ROLLING SAID DISCRETE PARTICLES INTO LARGE COHERENT SPHEROIDAL AGGREGATES, HAVING SUFFICIENT STRUCTURAL STRENGTH TO WITHSTAND FURTHER HANDLING AND PROCESSING, SAID ROLLING BEING ACCOMPLISHED WITHOUT THE APPLICATION OF LARGE PARTICLE-TO-PARTICLE CONTACT PRESSURES.