Abstract: The invention relates to a novel process for the preparation of precipitated silica which can be used as a reinforcing filler for elastomers. The invention also relates to novel precipitated silicas in the form of powder, granules or, preferably, substantially spherical beads, these silicas being characterized in that they have a BET specific surface of between 185 and 250 m2/g, a CTAB specific surface of between 180 and 240 m2/g, and a pore distribution such that the pore volume V2 made up of the pores with a diameter of between 175 and 275 ? represents less than 50% of the pore volume V1 made up of the pores with diameters of less than or equal to 400 ?, a pore volume (Vd1), made up of the pores with a diameter of less than 1 ?m, of greater than 1.65 cm3/g, a fineness value (F.V.) of between 70 and 100 ?, and a content of fines (?f), after deagglomerability with ultrasound, of at least 50%.

Abstract: The invention relates to a novel process for the preparation of precipitated silica which can be used as a reinforcing filler for elastomers. The invention also relates to novel precipitated silicas in the form of powder, granules or, preferably, substantially spherical beads, these silicas being characterized in that they have a BET specific surface of between 185 and 250 m2/g, a CTAB specific surface of between 180 and 240 m2/g, and a pore distribution such that the pore volume V2 made up of the pores with a diameter of between 175 and 275 ? represents less than 50% of the pore volume V1 made up of the pores with diameters of less than or equal to 400 ?, a pore volume (Vd1), made up of the pores with a diameter of less than 1 ?m, of greater than 1.65 cm3/g, a fineness value (F.V.) of between 70 and 100 ?, and a content of fines (?f), after deagglomerability with ultrasound, of at least 50%.

Abstract: The invention relates to a novel process for the preparation of precipitated silica which can be used as a reinforcing filler for elastomers. The invention also relates to novel precipitated silicas in the form of powder, granules or, preferably, substantially spherical beads, these silicas being characterized in that they have a BET specific surface of between 185 and 250 m2/g, a CTAB specific surface of between 180 and 240 m2/g, and a pore distribution such that the pore volume V2 made up of the pores with a diameter of between 175 and 275 ? represents less than 50% of the pore volume V1 made up of the pores with diameters of less than or equal to 400 ?, a pore volume (Vd1), made up of the pores with a diameter of less than 1 ?m, of greater than 1.65 cm3/g, a fineness value (F.V.) of between 70 and 100 ?, and a content of fines (?f), after deagglomerability with ultrasound, of at least 50%.

Abstract: The invention relates to a novel process for the preparation of precipitated silica which can be used as a reinforcing filler for elastomers. The invention also relates to novel precipitated silicas in the form of powder, granules or, preferably, substantially spherical beads, these silicas being characterized in that they have a BET specific surface of between 185 and 250 m2/g,a CTAB specific surface of between 180 and 240 m2/g,and a pore distribution such that the pore volume V2 made up of the pores with a diameter of between 175 and 275 Å represents less than 50% of the pore volume V1 made up of the pores with diameters of less than or equal to 400 Å, a pore volume (Vd1), made up of the pores with a diameter of less than 1 &mgr;m, of greater than 1.65 cm3/g, a fineness value (F.V.) of between 70 and 100 Å, and a content of fines (&tgr;f), after deagglomerability with ultrasound, of at least 50%.

Abstract: The invention relates to a novel process for the preparation of precipitated silica which can be used as a reinforcing filler for elastomers. The invention also relates to novel precipitated silicas in the form of powder, granules or, preferably, substantially spherical beads, these silicas being characterized in that they have a BET specific surface of between 185 and 250 m2/g, a CTAB specific surface of between 180 and 240 m2/g, and a pore distribution such that the pore volume V2 made up of the pores with a diameter of between 175 and 275 Å represents less than 50% of the pore volume V1 made up of the pores with diameters of less than or equal to 400 Å, a pore volume (Vd1), made up of the pores with a diameter of less than 1 &mgr;m, of greater than 1.65 cm3/g, a fineness value (F.V.) of between 70 and 100 Å, and a content of fines (&tgr;f), after deagglomerability with ultrasound, of at least 50%.

Abstract: Activated alumina agglomerates having a crush resistance of at least 12 daN, measured on that fraction thereof having a mean diameter ranging from 3 to 4 mm, and an adsorptive capacity greater than 18% by weight, well adopted as adsorbents in a wide variety of purification processes, are prepared by agglomerating activated alumina particulates, maturing the resulting agglomerates in the presence of a complexing agent for the cation Al.sup.3+, and then thermally treating the matured agglomerates at a temperature ranging from about 100.degree. to 500.degree. C.

Abstract: Activated alumina agglomerates having a crush resistance of at least 12 daN, measured on that fraction thereof having a mean diameter ranging from 3 to 4 mm, and an adsorptive capacity greater than 18% by weight, well adopted as adsorbents in a wide variety of purification processes, are prepared by agglomerating activated alumina particulates, maturing the resulting agglomerates in the presence of a complexing agent for the cation Al.sup.3+, and then thermally treating the matured agglomerates at a temperature ranging from about 100.degree. to 500.degree. C.

Abstract: Sulfur-free anatase titanium dioxide, readily dispersible in aqueous media and well adopted for the production of electronic-grade alkaline earth metal titanates, e.g., barium and strontium titanates, is prepared by hydrolyzing a sulfur-free compound of titanium in the presence of (i) at least one acid containing either one carboxyl group and at least two hydroxyl and/or amino groups, or at least two carboxyl groups and at least one hydroxyl and/or amino group, or (ii) at least one salt of the at least one acid (i).

Abstract: Poorly crystallized or amorphous TiO.sub.2 particulates having a mean particle size greater than 20 nm are prepared by thermally hydrolyzing a titanium compound in solution, in the presence of at least one carboxylic acid containing a hydroxyl and/or amino group, or an organophosphoric acid; the TiO.sub.2 particulates thus produced are readily molded/extruded into useful shaped articles, e.g., catalysts or catalyst supports, having good porosity and mechanical properties.

Abstract: Poorly crystallized or amorphous TiO.sub.2 particulates having a mean particle size greater than 20 nm are prepared by thermally hydrolyzing a titanium compound in solution, in the presence of at least one carboxylic acid containing a hydroxyl and/or amino group, or an organophosphoric acid; the TiO.sub.2 particulates thus produced are readily molded/extruded into useful shaped articles, e.g., catalysts or catalyst supports, having good porosity and mechanical properties.

Abstract: Gallium values are extracted and recovered from basic aqueous solutions thereof, notably from sodium aluminate solutions of Bayer process origin, by liquid/liquid extraction thereof with a water immiscible organic phase comprising an organic solvent having dissolved therein an organic-soluble substituted hydroxyquinoline and at least one organic-soluble organophosphorus compound comprising at least one acid function.

Abstract: Gallium values are extracted and recovered from basic aqueous solutions thereof, notably from sodium aluminate solutions of Bayer process origin, by liquid/liquid extraction thereof with a water immiscible organic phase comprising an organic solvent having dissolved therein an organic-soluble substituted hydroxyquinoline and at least one organic-soluble organosulfate or organosulfonate comprising at least one acid function, either in the free acid or salt form thereof.