Abstract: Process for the production of cleansing, polishing and thickening silica for use in toothpastes, which is characterized in that using the conventional precipitation processes, silica suspensions are obtained of various particles sizes and particle densities and are mixed thoroughly together until the mixture is homogenous in the suspension phase and the resulting suspension mixture is treated in the conventional manner by filtering, drying and comminuting.

Abstract: Precipitated silicas which have the following physicochemical characteristics, depending on the manner in which they are milled:______________________________________ Pendulum roller mill Jet mill ______________________________________ BET m.sup.2 /g 15-110 15-110 surface area Tamped g/l 150-750 90-650 den- sity Cu abrasion in 10% mg 5-30 5-30 strength glycerol dispersion Lightness % 86-96 90-96 value Particle size dis- as in FIG. 1 as in FIG. 2 tribution curve determined by a Coulter Counter "ALPINE screen retain- % by <1.5 <0.1 ings" >63 .mu.m weight Viscosity of a 30% mPa.s 30,000 to 60,000 strength dispersion in a 1:1 glycerol/water mixture (Brookfield RTV, Sp5) ______________________________________are prepared by diluting a precipitated silica original suspension obtained according to German Published Application DAS 1,467,019 and simultaneously adding alkali metal silicate solution, sulfuric acid and water while keeping the pH constant between 7 and 9.

Abstract: There are disclosed precipitated silicas which are characterized by the following physical-chemical data:______________________________________ A B C ______________________________________ BET-surface area m.sup.2 /g 400-600 400-600 400-600 according to DIN 66131 DBP-Number % 340-380 320-360 310-360 Bulk density according g/l 180-220 75-120 35-70 to DIN 53194 "ALPINE-Sieve Wt. % 25-60 <0.1 <0.01 Residue" >63 m.mu. ______________________________________Depending on the particle distribution curve, these precipitated silicas can be employed as silica carriers for active materials of all types, as antiblocking agents for polypropylene and polyethylene films, as thickening silica in specific polar systems in which pyrogenic silicas show little thickening capacity, as highly active matting agents for varnishes and as catalyst carriers as well as insulating materials.

Abstract: Cerium containing precipitated silica is disclosed as well as a process for its production as well as compositions hardenable to elastomers which contain the cerium containing precipitated silica. The precipitated silica______________________________________ BET-surface area according to DIN 66 131 m.sup.2 /g 140 .+-. 40 Loss on drying according to DIN 55 921 Wt.-% 2.0-4.0 Loss on ignition according to DIN 55 921 Wt.-% 2.5-12.5 pH-according to DIN 53 200 3.0-7.0 Conductivity in 4% aqueous dispersion at 20.degree. C. .mu.s 500 Packed density according to DIN 53 194 g/l 80 .+-. 40 CeO.sub.2 -content, based on the material dried for 2 hours at 105.degree. C. Wt.-% 0.3-50 Sieve residue according to Mocker 45 .mu.m (DIN 53 580) Wt.-% 0.2 ______________________________________They are prepared by adding a cerium (IV) salt solution to the original precipitated suspension of a precipitated silica.

Abstract: Finely divided precipitated silicic acid is obtained by the method of the invention.Compositions containing the finely divided precipitated silicic acid as a filler distributed in an elastomer such as an organopolysiloxane are disclosed.

Abstract: There is prepared precipitated silica containing boron and having the following physical-chemical data______________________________________ Loss on heating Weight % 14-40 pH 4-6 Conductivity in 4% aqueous /.mu.S <800 dispersion Bulk density g/l 130 .+-. 100 Sieve residue according to Alpine >63/.mu. Weight % <0.1 SiO.sub.2 content based on original Weight % 9-76 material B.sub.2 O.sub.3 content based on original Weight % 10-51 material Na.sub.2 O content based on original Weight % <0.5 material So.sub.3 content based on original Weight % <0.8 material ______________________________________The product is obtained by supplying precipitated silica and ortho boric acid in the ratio of 0.1-3.5:1 continuously to a jet mill and micronizing them together by means of the air of the mill at room temperature.

Abstract: Finely divided precipitated silicic acid is obtained by the method of the invention.Compositions containing the finely divided precipitated silicic acid as a filler distributed in an elastomer such as an organopolysiloxane are disclosed.

Abstract: A silicic acid filter cake and suspension agent are fed to a container equipped with a stirrer having a peripheral speed of about 20-30 m/sec. The ratio of container diameter to stirrer diameter is about 3:1. The ratio of container diameter to level of filling is a maximum of about 1:2. The container contains at least about 1.5 to about 2 kg of silicic acid suspension, for each 1 kg of silicic acid filter cake which is added to the container. The contents of the container is mixed while maintaining a pH of at most about 4. A portion of the resulting silicic acid suspension is drawn off from the zone of highest turbulence in the container. An apparatus for carrying out the process is provided.

Abstract: A finely divided silicic acid having a pH>6 is prepared by spray drying, in the presence of a base or basic-reacting substance, a highly concentrated silicic acid suspension having excess, unwanted acidity.

Abstract: Hydrophobic precipitated silicic acid is disclosed and its use as a reinforcing filler in plastic masses which are hardenable to form elastomers.

Abstract: Free flowing, finely divided precipitated silicic acid granules of reduced dust content and reduced abrasion are obtained by a process including the step of subjecting a silicic acid suspension to intensive shearing action. Rubber compositions containing the precipitated silica produced in this way are also disclosed.

Abstract: A silicic acid filter cake and suspension agent are fed to a container equipped with a stirrer having a peripheral speed of about 20-30 m/sec. The ratio of container diameter to stirrer diameter is about 3:1. The ratio of container diameter to level of filling is at most about 1:2. The container contains at least about 1.5 to about 2 kg of silicic acid suspension, for each 1 kg of silicic acid filter cake which is added to the container. The contents of the container is mixed while maintaining a pH of at most about 4. A portion of the resulting silicic acid suspension is drawn off from the zone of highest turbulence in the container.

Abstract: Modified silicic acids, gels, and silicates are produced by impregnation with a wax or a thermoplastic material, such as polyethylene. The silicic acids, silica gels, or silicates can be impregnated either as they are being formed or after they have formed by adding an aqueous suspension or dispersion of wax thermoplastic material to the silicic acids, gels or silicates. The mixture is then filtered, washed, dried, and finely ground. The organically modified silicic acids, gels, and silicates are useful as delustering agents in lacquer systems.