Abstract: Spinel black pigments are prepared by annealing oxides, hydroxides or carbonates of copper, chromium and manganese and grinding the product. The manganese-yielding component is Mn.sub.3 O.sub.4.

Abstract: Chromium-antimony-rutile mixed phase pigments containing from 0.01 to 0.25% by weight of lithium are surprisingly insensitive to rapid cooling and chilling and are used for coloring plastic compositions such as polyamide or ABS plastics.

Abstract: The invention provides a process for the production of zeolite A from kaolin by conversion of the kaolin into meta-kaolin followed by reaction of the meta-kaolin in an aqueous alkaline medium, wherein the conversion of the kaolin into the meta-kaolin is conducted at temperatures of between 700.degree. and 950.degree. C. in the presence of alkaline earth compounds and optionally in the presence of uncolored halides and/or halogens, wherein the process may be conducted under reducing conditions and in the presence of alkali metal compounds.

Abstract: In a process for the production of olefins in two stages wherein, in the first stage, heavy petroleum fractions are hydrogenated in the presence of hydrogen and a hydrogenation catalyst and, in the second stage, the thus-hydrogenated fractions are subjected to thermal cracking the presence of steam, the improvement which comprises employing as the hydrogenation catalyst a zeolite of the faujasite structure combined with elements from Groups VIB, VIIB and VIII of the periodic table of the elements, wherein the alkali component of the zeolite is exchanged at least partially for ammonium, hydronium, alkaline earth and/or rare earth ions, and the elements are present in a metallic, ionic, oxidic and/or sulfidic form.

Abstract: Quartz glass of high thermal stability is produced from a SiO.sub.2 solution or sol which is substantially free of alkali and alkaline earth metal oxides and contains chromium and/or manganese in about 0.05 to 20% by weight of the SiO.sub.2 expressed as Cr.sub.2 O.sub.3 and Mn.sub.2 O.sub.3. The quartz glass upon heating above 1100.degree. C. forms cristobalite having an average crystallite size of about 100 to 500 A. Articles therefrom retain their physical and mechanical properties at high temperatures. The materials are suited for producing fibers by the usual methods of spinning from solutions or sols and, as such, or as fibers they are suited for use in reinforcement and insulation and in making flameproof textiles.

Abstract: Quartz glass of high thermal stability is produced from a SiO.sub.2 solution or sol which is substantially free of alkali and alkaline earth metal oxides and contains chromium and/or manganese in about 0.05 to 20% by weight of the SiO.sub.2 expressed as Cr.sub.2 O.sub.3 and Mn.sub.2 O.sub.3. The quartz glass upon heating above 1100.degree. C forms cristobalite having an average crystallite size of about 100 to 500 A. Articles therefrom retain their physical and mechanical properties at high temperatures. The materials are suited for producing fibers by the usual methods of spinning from solutions or sols and, as such, or as fibers they are suited for use in reinforcement and insulation and in making flameproof textiles.

Abstract: A process for the production of chromium oxide green pigment comprising heating a mixture of ammonium dichromate with at least the stoichiometrically equivalent quantity of a sodium salt selected from the group consisting of chloride and sulfate over a period of at most about 15 minutes to a pigment-forming temperature of about 800 to 1100.degree. C in the presence of about 1 to 45% water based on the weight of the mixture, calcining the mixture at a temperature in the above-mentioned range, and separating the formed pigment from the salts. The mixture may be formed in situ by reaction of sodium dichromate with ammonium chloride or sulfate in the presence of water. The presence during calcining of organic modifiers such as sawdust or of boron compounds such as borax increases, tinting strength and disproportionately affect color. The pigments are brighter, and of higher tinting strength than heretofore produced.

Abstract: In the continuous production of low-sulfur chromium(III)oxide pigment comprising the steps of reducing a finely divided alkali metal chromate in a heated hydrogen-containing reaction zone at a temperature of about 900.degree. to 1600.degree. C, and precipitating the resulting chromium(III)oxide in the form of an aqueous dispersion, the improvement which comprises passing the reduction products from the reaction zone to a dwell zone and generating heat within said dwell zone to maintain the temperature therein in the range of about 900.degree. to 1600.degree. C. Preferably the dwell zone temperature is within 200.degree. C of that in the reaction zone and is maintained by introducing excess hydrogen into the reaction zone and consuming it in the dwell zone by introduction of oxygen. The resulting pigments exhibit a fuller green color.

Abstract: In the production of chromium oxide green pigment by heating a substantially stoichiometrically equivalent mixture of sodium dichromate dihydrate and an ammonium salt selected from the group consisting of the sulfate and chloride, the improvement which comprises dry mixing sodium dichromate dihydrate having a particle size less than 2 mm with the ammonium salt having a particle size less than about 0.5 mm, heating the resulting mixture over a period of about 15 minutes to a pigment-forming temperature of about 800.degree. to 1100.degree. C, calcining the mixture at a temperature in that range, and separating the formed pigment from the salts. To the mixture prior to heating there may be added sodium hydroxide solution, boron compounds such as borax and/or organic modifiers such as sawdust which improve the color and tinting strength of the resulting pigment. The pigments are brighter, and of higher tinting strength than heretofore produced.

Abstract: The invention relates to the production of inorganic fibers comprising a metal oxide phase and a finely divided disperse phase distributed throughout the oxide phase, the disperse phase constituting about 0.5 to 50% by weight of the fiber. The process involves preferably dry spinning a solution in water or an organic solvent of fiber forming components which, when heated to temperature of from 500.degree. to 1600.degree. C either in an inert or in a reactive atmosphere, form at least two phases with a miscibility gap, of which one phase is an oxide phase containing the other phase in very finely disperse form. Preferably, the solution contains a metal salt, the anion of which contains carbon so that upon heating there is formed an oxide phase comprising the oxide of said metal having carbon dispersed therein; if carbon is not in the anion, its precursor may be an organic compound, such as a polymer, present in the solution.

Abstract: Aluminum oxide fibers of the approximate percent composition by weight:______________________________________ Al.sub.2 O.sub.3 61-98% preferably 76-96% SiO.sub.2 1-20% preferably 3-15% P.sub.2 O.sub.5 0-10% preferably 0-5% B.sub.2 O.sub.3 0-10% preferably 0-5% MgO 0-5% preferably 0-1% C 0.1-4% preferably 0.5-2.8% ______________________________________The fibers are produced by dry spinning a solution containing a neutral or basic aluminum salt of a monobasic lower carboxylic acid, a hydrolyzed silicic acid ester or organoalkoxysilane and polyethylene oxide having a degree of polymerization of at least about 2,000. The product is then heat treated at a temperature between about 400.degree. and 1,800.degree.C. Phosphorus, boron and magnesium may also be present in the solution and end up in the fiber as oxides.

Abstract: In the production of aluminum oxide fibers comprising dry spinning an aluminum-containing solution to produce fiber and thereafter heat treating the fiber, the improvement which comprises applying to the fiber prior to heat treatment a solution of polyvinyl acetate in a solvent which is inert to the fiber. Advantageously the polyvinyl acetate is present in its solution in a concentration of about 0.1 to 10% by weight and is applied to the fiber in about 0.1 to 3 % by weight. The spinning solution may also contain SiO.sub.2 and polyethylene oxide, and the polyvinyl acetate solution may also contain di-n-butyl phthalate as a plasticizer for the polyvinyl acetate. The fiber bundles are characterized by increased strength and resistance to breaking during further processing.