Spherically-shaped silica can include a precipitated silica powder having a d.sub.50 particle size selected within a range of greater than 20 ?m and up to 80 ?m, a di-octyl adipate oil absorption selected within a range of from 150 ml/100 g to 500 ml/100 g, an average circularity selected within a range of from 0.70 to 1.0, and an angle of repose, of less than 30?. A process of preparing spherically-shaped silica powder is also included.

The silica sol of the invention contains silica particles having a mean primary particle size of 20 to 100 nm and which has a silica particle size/mean primary particle size ratio, determined through dynamic light scattering, of 3.0 or less, wherein the silica particles are surface-treated with an organic silane compound and have an -ray emission rate of 0.005 counts/cm.sup.2.Math.hr or less and a moisture absorption coefficient, determined after allowing the silica particles to stand for 48 hours at 23 C. and a relative humidity of 50 RH %, of 0.5 mass % or lower.

It is provided a process of producing amorphous silica from a raw material, such as serpentine, containing silica comprising the steps of mixing the raw material with a hydrochloric acid solution; leaching the raw material obtaining a slurry comprising a liquid fraction and a solid fraction containing silica and minerals; separating the liquid fraction and the solid fraction; removing the minerals from the solid fraction by magnetic separation producing a purified solid silica; drying the purified solid silica; and heating the purified solid silica to remove hydroxyl groups from the silica surface and reducing specific surface area of the resulting amorphous silica.

A precipitated silica production process that includes a precipitation reaction between a silicate and an acid is described, in which the acid used in at least one of the steps of the process is a concentrated acid.

A unique method for preparing precipitated silica entails reacting a silicate with an acidifying agent to obtain a suspension of precipitated silica, and separating and drying the suspension, and further wherein the precipitation includes contacting a silicate with an acidifying agent in an acidic medium in a fast blender.

A process comprising: A) contacting one or more of sources of silicon oxide, selected from water soluble.silica sources arid alkali metal silicates, with an aqueous reaction medium, comprising one or more nonionic surfactants and thereby forming mesoporous structures comprising crosslinked silicon oxide units, wherein said crosslinked silicon oxide units have pores of about 1 to about 100 nanometers and wherein the aqueous reaction medium exhibits a pH of about 0 to about 4.0; B) exposing the aqueous reaction medium containing the mesoporous structures to elevated temperatures for a time sufficient to achieve the desired structure and pore size. Preferred water soluble silica sources comprise silicic acid, or polysilicic acids, The aqueous reaction, medium is prepared by combining one or more nonionic surfactants and water, theteby forming an aqueous, reaction medium, comprising micelles. Preferably, the aqueous reaction medium further comprises, a. micelle swelling agent capable of swelling micelles formed by the surfactant in the aqueous reaction medium. In one embodiment the process forms structures with struts comprised of crosslinked silicon oxides which connect at least some of the pore forming structures.

The present disclosure relates to a novel process for the preparation of a precipitated silica, in which: a silicate is reacted with at least one acidifying agent, so as to obtain a suspension of precipitated silica, said suspension of precipitated silica is filtered, so as to obtain a filtration cake, said filtration cake is subjected to a liquefaction operation comprising the addition of an aluminum compound, after the liquefaction operation, a drying stage is carried out, characterized in that methylglutaric acid is added to the filtration cake, during or after the liquefaction operation. It also relates to novel precipitated silicas and to their uses.

A process for preparing precipitated silicas in which: (i) an aqueous stock with a pH of between 2 and 5 is formed; (ii) silicate and acid are simultaneously added to said stock, such that the pH of the resulting reaction medium is maintained between 2 and 5; (iii) silicate is added until a pH value of between 7 and 10 is obtained; (iv) silicate and acid are simultaneously added, such that the pH of the reaction medium is between 7 and 10; (v) acid is added until a pH value of between 2.5 and 5.3 is obtained; and (vi) the reaction medium is placed in contact with acid and silicate, such that the pH is between 2.5 and 5.3; wherein the acid used in at least one of the process steps is a concentrated acid.

The invention relates to a process for the preparation of precipitated silica formed of aggregates of large primary silica particles, at the surface of which occur small primary silica particles, in which the acid used in at least one of the process steps is a concentrated acid.

Superhydrophobic coatings and compositions and methods for preparing superhydrophobic coatings and compositions are described herein whereby the coatings and compositions are prepared under mild conditions, yet the methods are amenable to chemical functionalization of the coatings and components therein. The methods are useful for tuning and optimizing the physical properties of the coatings. In an embodiment, the coatings comprise nanostructured fluorinated silica colloids.