Chemically modified alumina monohydrate, dispersions thereof and processes for their preparation

Claim 2

A CHEMICALLY MODIFIED ALUMINA MONOHYDRATE IN THE FORM OF COLLOIDAL ANISODIAMETRIC PARTICLES BEING CHARACTERIZED BY HAVING (A) A SPECIFIC SURFACE AREA OF 50 TO 450 M.2/G. AS DETERMINED BY NITROGEN ADSORPTION; (B) AN X-RAY DIFFRACTION PATTERN HAVING LINES AT 3.1-3.2 ANGSTROMS, 2.3-2.4 ANGSTROMS, 1.8-1.9 ANGSTROMS, THE STRONGEST LINE BEING IN THE RANGE BETWEEN 6.2 AND 6.7 ANGSTROMS; (C) FROM 3 EQUIVALENT PERCENT BASED ON ALUMINUM TO X EQUIVALENT PERCENT OF A POLYVALENT ANION WHERE X IS THE MAXIMUM AMOUNT OF POLYVALENT ANION THAT CAN BE CHEMICALLY INCORPORATED INTO THE ALUMINA MONOHYDRATE CRYSTAL LATTICE HAVING THE FOREGOING XRAY DIFFRACTION PATTERN.

Claim 3

A DISPERSION OF THE PARTICLES OF CLAIM 1 IN WATER.

Claim 4

IN A PROCESS FOR MAKING A COLLOIDAL CHEMICALLY MODIFIED ALUMINA MONOHYDRATE, THE STEPS OF (1) MIXING FROM 3 TO 30 EQUIVALENT PERCENT, BASED ON ALUMINUM, OF A POLYVALENT ANION WITH AN AQUEOUS ACIDIC SUSPENSION OF ALUMINA AND THEN (2) HEATING UNDER THE FOLLOWING CONDITIONS THE RESULTING MIXTURE UNTIL THE ALUMINA MONOHYDRATE PARTICLES ARE FORMED: (A) THE ALUMINA STARTING MATERIAL IS SUCH THAT ONE HALF CAN BE DISSOLVED AT 98*C., IN AN EXCESS OF HYDROCHLORIC ACID IN A TIME, B, OF LESS THAN ONE MINUTE. (B) THE SYSTEM CONTAINS A MONOBASIC ACID RADICAL HAVING A DISSOCIATION CONSTANT GREATER THAN 0.1 AT 25*C., (C) THE AL2O3 CONTENT OF THE SYSTEM IS FROM 0.05 TO 1.5 MOLAR, (D) THE ACID RADICAL CONCENTRATION IS NO LESS THAN 0.05 MOLAR AND DOES NOT EXCEED 4.2 MOLAR, (E) THE SAID TEMPERATURE OF HEATING IS 120 TO 250*C.

Claim 5

IN A PROCESS FOR MAKING A COLLOIDAL CHEMICALLY MODIFIED ALUMINA MONOHYDRATE, THE STEPS OF (1) MIXING FROM 3 TO 30 EQUIVALENT PERCENT, BASED ON ALUMINUM, OF A POLYVALENT ANION WITH AN AQUEOUS ACIDIC SUSPENSION OF ALUMINA AND THEN (2) HEATING UNDER THE FOLLOWING CONDITIONS THE RESULTING MIXTURE UNTIL THE ALUMINA MONOHYDRATE PARTICLES ARE FORMED: (A) THE ALUMINA STARTING MATERIAL IS SUCH THAT ONE HALF CAN BE DISSOLVED AT 98*C., IN AN EXCESS OF HYDROCHLORIC ACID IN A TIME, B, OF LESS THAN ONE MINUTE. (B) THE SYSTEM CONTAINS A MONOBASIC ACID RADICAL HAVING A DISSOCIATION CONSTANT GREATER THAN 0.1 AT 25*C., (C) THE AL2O3 CONTENT OF THE SYSTEM IS FROM 0.05 TO 1.5 MOLAR, (D) THE ACID RADICAL CONCENTRATION IS NO LESS THAN 0.05 MOLAR AND DOES NOT EXCEED 4.2 MOLAR, (E) THE SAID TEMPERATURE OF HEATING IS 120 TO 250*C.