Thermally stable phosphate containing alumina precipitates and their method of preparation

Claim 1

A thermally stable composite precipitate containing from 10 to 60 mole percent alumina and from 40 to 90 mole percent aluminum phosphate, said composite precipitate being characterized after calcination at 500° C. for 16 hours as: amorphous; having a surface area from about 100 to about 200 m 2 /g; having an average pore radius of from 75 to 150 A; and wherein no more than a 30% decrease in surface area is obtained if said composite precipitate is further calcined at a temperature up to about 900° C. for up to 16 hours.

Claim 9

A method of preparing a thermally stable composite precipitate containing from 10 to 60 mole percent alumina and from 40 to 90 mole percent aluminum phosphate, which comprises: forming a first aqueous solution of aluminum cations and PO 4 --- anions wherein the molar ratio of the PO 4 --- anions to the aluminum cations is 0.82:1 to 0.25:1; neutralizing said first aqueous solution with ammonia gas or a second aqueous solution of an ammonia based material selected from the group consisting of ammonium hydroxide, ammonium carbonate, ammonium bicarbonate or urea in such a manner that the pH of the combined first aqueous solution and the neutralizing medium is controlled in the range of 7 to 10.0; recovering said precipitate; drying said precipitate; and calcining said precipitate at a temperature from 300° C. to 500° C. for a time up to 16 hours to form an amorphous aluminum phosphate composite material having a surface area from about 100 to about 200 m 2 /g, an average pore radius from 75 to 150 A and wherein no more than a 30% decrease in surface area is obtained if said composite precipitate is calcined at 500° C. for 16 hours and further calcined at a temperature up to about 900° C. for up to 16 hours.

Claim 10

A method of preparing a thermally stable composite precipitate containing from 10 to 60 mole percent alumina and from 40 to 90 mole percent aluminum phosphate, which comprises: forming a first aqueous solution of aluminum cations and PO 4 --- anions wherein the molar ratio of the PO 4 --- anions to the aluminum cations is 0.82:1 to 0.25:1; neutralizing said first aqueous solution with ammonia gas or a second aqueous solution of an ammonia based material selected from the group consisting of ammonium hydroxide, ammonium carbonate, ammonium bicarbonate or urea in such a manner that the pH of the combined first aqueous solution and the neutralizing medium is controlled in the range of 7 to 10.0; recovering said precipitate; drying said precipitate; and calcining said precipitate at a temperature from 300° C. to 500° C. for a time up to 16 hours to form an amorphous aluminum phosphate composite material having a surface area from about 100 to about 200 m 2 /g, an average pore radius from 75 to 150 A and wherein no more than a 30% decrease in surface area is obtained if said composite precipitate is calcined at 500° C. for 16 hours and further calcined at a temperature up to about 900° C. for up to 16 hours.