PROCESS FOR PRODUCING POROUS SPHERICAL SILICA GEL PARTICLES

1 . A process for forming a porous spherical silica, the process comprising:

a. mixing an alkali silicate with a mineral acid at pH and a temperature sufficient to form a silica sol,

b. mixing the silica sol with an oil and a surfactant to form an emulsion,

c. adding an alkaline solution to the emulsion at a time and temperature sufficient to form a gel,

d. adding a demulsifying agent and heating at a temperature sufficient to separate porous spherical silica particles from the oil,

e. washing and optionally aging the particles, and

f. drying the porous spherical silica particles.

2 . The process of claim 1 , wherein the alkali silicate is sodium silicate.

3 . The process of claim 1 , wherein the mineral acid is sulfuric acid or hydrochloric acid.

4 . The process of claim 1 , wherein the oil comprises mineral oil.

5 . The process of claim 1 , wherein the surfactant comprises a nonionic surfactant.

6 . The process of claim 5 , wherein the nonionic surfactant comprises a sorbitan ester.

7 . (canceled)

8 . The process of claim 1 , wherein the alkaline solution comprises ammonium hydroxide.

9 . The process of claim 1 , wherein the emulsion is maintained at a temperature of from about 40°° C. to about 90° C. for about 0.25 to about 2 hours prior to adding the demulsifying agent.

10 . The process of claim 1 , wherein the alkaline solution is added until the pH reaches a level of from about 5 to about 10.

11 . (canceled)

12 . The process of claim 1 , wherein the silica sol is formed at a temperature less than 25° C.

13 . The process of claims 1 , wherein the particles are aged after washing prior to drying.

14 . The process of claim 13 , wherein the particles are aged at a pH from about 7 to about 9 at a temperature from about 60°° C. to about 90° C. for a time period of about 1 to about 4 hours.

15 . The process of claim 1 , wherein the emulsion is formed by mixing the silica sol with a mixture comprising oil and surfactant.

16 . The process of claim 15 , wherein the concentration of surfactant in the surfactant/oil mixture ranges from about 3 wt. percent to about 25 wt. percent of the mixture.

17 . (canceled)

18 . (canceled)

19 . The process of claim 1 , wherein the ratio of silica sol to the surfactant/oil mixture ranges from about 1:5 to about 5:1.

20 . (canceled)

21 . (canceled)

22 . The process of claim 1 , wherein the demulsifying agent comprises a mineral acid.

23 . A silica material formed by the process of claim 1 , the silica material comprising:

a plurality of single silica gel particles, each particle comprising an amorphous network, the particles having an average aspect ratio of about 1.2 or less, a pore volume of from about 0.5 cc/g to about 2.5 cc/g, a surface area from about 300 m2/g to about 800 m2/g; and a median particle size from about 3 μm to about 40 μm.

24 . A silica material formed by the process of claim 1 , the silica material comprising:

a plurality of single silica gel particles, each particle comprising an amorphous network, the particles having an average aspect ratio of about 1.2 or less, a pore volume of from about 0.8 cc/g to about 2.0 cc/g, a surface area from about 400 m 2 /g to about 700 m 2 /g; and a median particle size from about 8 μm to about 40 μm.

25 . The silica material of claim 23 , wherein the silica particles have a span of about 2.0 or less and/or wherein the silica particles have an average pore size of from about 30 to about 250 Angstrom.

26 . The silica material of claim 24 , wherein the silica particles have a span of about 2.0 or less and/or wherein the silica particles have an average pore size of from about 30 to about 250 Angstrom.