Novel spheroidal silica particulates

Claim 2

Macroporous, granular, spheroidal silica particulates which are mechanically strong and stable in aqueous media, said particulates having the following distribution of pore volumes to pore size: ______________________________________ φ in Å <100 100-1,000 1,000-10,000 >10,000 ν cm.sup.3 /g 0-0.60 0.05-0.50 0.05-0.20 0.05-0.20 ______________________________________ wherein φ is pore diameter and ν the corresponding pore volume.

Claim 3

The spheroidal silica particulates as defined by claim 1, wherein the diameters range from 1 to 10 mm.

Claim 4

The spheroidal silica particulates as defined by claim 1, wherein said particulates have diameters of at least 5 mm.

Claim 5

The spheroidal silica particulates as defined by claim 1, wherein said particulates have a macroporosity volume greater than 0.5 cm 3 /g.

Claim 6

The spheroidal silica particulates as defined by claim 4, wherein said particulates have a macroporosity volume greater than 0.7 cm 3 /g.

Claim 7

A catalyst comprising the spheroidal silica particulates as defined by claim 1.

Claim 8

A catalyst support comprising the spheroidal silica particulates as defined by claim 1.

Claim 9

A process for the preparation of macroporous, granular, spheroidal silica particulates which are mechanically strong and stable in aqueous media, said particulates having the following distribution of pore volumes to pore size: ______________________________________ φ in Å <100 100-1,000 1,000-10,000 >10,000 ν cm.sup.3 /g 0-0.60 0.05-0.50 0.05-0.20 0.05-0.20 ______________________________________ wherein φ is pore diameter and ν the corresponding pore volume, said process comprising the steps of (i) granulating and agglomerating a mixture of silica hydrosol and a silica xerogel or aerogel, said xerogel or aerogel comprising particles having a mean diameter of from 5 to 25 microns, and the amount of silica in the hydrosol, expressed as SiO 2 , and the amount of silica in said xerogel or aerogel, also expressed as SiO 2 , each ranging from 15 to 35% by weight, and (ii) drying the resultant silica particulates.

Claim 10

A process for the preparation of macroporous, granular, spheroidal silica particulates which are mechanically strong and stable in aqueous media, said particulates having the following distribution of pore volumes to pore size: ______________________________________ φ in Å <100 100-1,000 1,000-10,000 >10,000 ν cm.sup.3 /g 0-0.60 0.05-0.50 0.05-0.20 0.05-0.20 ______________________________________ wherein φ is pore diameter and ν the corresponding pore volume, said process comprising the steps of (i) granulating and agglomerating a mixture of silica hydrosol and a silica xerogel or aerogel, said xerogel or aerogel comprising particles having a mean diameter of from 5 to 25 microns, and the amount of silica in the hydrosol, expressed as SiO 2 , and the amount of silica in said xerogel or aerogel, also expressed as SiO 2 , each ranging from 15 to 35% by weight, and (ii) drying the resultant silica particulates.

Claim 11

The process as defined by claim 8, wherein the silica content of said hydrosol ranges from 18 to 30%.

Claim 12

The process as defined by claim 8, wherein the BET of the hydrosol, measured after drying at 200 °C., ranges from 150 to 500 m 2 /g.

Claim 13

The process as defined by claim 10, wherein said BET ranges from 300 to 450 m 2 /g.

Claim 14

The process as defined by claim 8, wherein said mean diameter ranges from 10 to 20 microns.

Claim 15

The process as defined by claim 8, wherein said drying is carried out at a temperature of from 200° to 800° C.