Abstract: A device for supporting and electrically contacting brushes, with which an electrical loop contact can be established with slip-rings on a shaft of a current generator or an electric motor. The device includes a support having a support base and a plurality of pins fastened thereto, through which at least one brush can be connected supportively with the support base. The device has at least one current distributor which can be electrically contacted in a short-circuiting manner with at least two brushes and can be connected to at least one electrical connection line. More than one of the pins function as an electrical contact pin with a contact surface and are integral components of at least one current distributor, so that at least one brush can be connected supportively through it and electrically contacted. The supporting base is electrically insulated at least in regions of connecting locations to the contact pins.

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: Iron blue pigment (DIN 55 906) is produced by white paste precipitation and subsequent oxidation of the white paste. Alakli or alkali metal ions i.e. sodium and potassium ions, cyanide or complex iron cyanide ions and iron ions are used as raw materials. The iron blue pigment according to the invention is characterized by a potassium content of 0.5-4.5% by weight, preferably 0.5-2.0% by weight, a sodium content of 0.2-1.0% by weight, an ammonium content of 2.0-4.5% by weight, preferably 3.0-4.5% by weight, a coloring power in accordance with DIN 53 204 and DIN 53 234 of 5-15% above the Vossen Blue 705 Standard and the following color intervals (determined in accordance with DIN 53 204 and DIN 53 234 in conjunction with DIN 6174, in relation to Vossen Blue 705 as standard):.DELTA.L: -0.7 to -1.5.DELTA.a: -0.5 to 1.5.DELTA.b: -0.6 to -2.3.DELTA.C: +0.5 to 2.

Abstract: Iron blue pigment (DIN 55 906) is produced by white paste precipitation and subsequent oxidation of the white paste. Alkali or alkali metal ions i.e. sodium and potassium ions, cyanide or complex iron cyanide ions and iron ions are used as raw materials. The iron blue pigment according to the invention is characterized by a potassium content of 7.0-9.0% by weight, preferably 7.6-9.0% by weight, a sodium content of 0.5-2.0% by weight, preferably 0.5-1.5% by weight, a coloring power according to DIN 53 204 and DIN 53 234 of 5-15% above the Vossen Blue 705 Standard and the following color intervals (determined in accordance with DIN 53 204 and DIN 53 234 in conjunction with DIN 6174, in relation to Vossen Blue 705 as standard):.DELTA.L: -0.7 to -1.5.DELTA.a: -0.5 to +0.3.DELTA.b: -0.6 to -2.3.DELTA.C: +0.5 to +2.

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: 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: Finely divided hydrophobic silica and silicates are prepared by precipitating of alkali silicate solutions with mineral acids or metal salt solutions and treated with organohalosilanes. To the acid precipitation suspension recovered in known manner there is added as a hydrophobizing agent an organohalosilane, preferably at about 50.degree. to 90.degree. C., the precipitated product filtered, washed and dried and there subjected to a temperature of 300.degree. to 400.degree. C. There is used as the organohalosilane a prepolycondensed organohalosilane or a mixture of prepolycondensed organohalosilanes.

Abstract: Ferrocyanide blue is produced by reacting an aqueous ferrocyanide solution with an iron II salt and subsequently aging of the precipitate at elevated temperature and optionally at elevated pressure as well as oxidation in acid medium. The improvement comprises simultaneously leading the aqueous solution of ferrocyanide and the ferrous salt solution into a water receiver, whereby optimum mixing occurs during the precipitation and whereupon the precipitate formed, the so-called white stage is aged in known manner directly in the reaction medium in the presence of the salts formed in the reaction at elevated temperature and optionally under pressure and likewise in known manner is converted into Berlin blue by oxidation in acid medium.

Abstract: Finely divided hydrophobic silica or silicate is produced by treating the dry, moving particles with an organic silane at elevated temperature. The silica or silicate which had been prepared by wet precipitation or pyrogenically and which is in powdered form is heated to a temperature of about 200.degree. to 300.degree. C. with agitation and is brought to a fluidized condition and then is treated dropwise with an organosilane which is stable and boils below 300.degree. C.

Abstract: Berlin blue is produced by converting (a) calcium ferrocyanide, sodium ferrocyanide or magnesium ferrocyanide with (b) an iron II salt at a pH below 7 to an acidic iron II salt of ferrocyanic acid FeH.sub.2 [Fe(CN).sub.6 ]. The calcium or sodium ions can be washed out of the precipitate of the ferrocyanic salt. The precipitate is treated with (c) an inorganic or organic potassium salt to form Berlin white and then oxidized to Berlin blue. Alternatively, (a), (b) and (c) can be reacted together at a temperature of 20.degree. to 60.degree.C. to form Berlin white directly.

Abstract: Voluminous precipitates or suspensions are contacted countercurrently with liquid purification or extraction agents that hold the continuously supplied precipitate or suspension in the upwardly flowing liquid in a kind of fluidized bed. A suitable apparatus is also described.