Abstract: A process is disclosed for coloring building materials with inorganic pigments in the form of microgranulates. The granulates comprise one or more pigments and one or more compounds selected from boron, aluminum, silicon, titanium, zinc and tin.

Abstract: Novel rutile mixed phase pigment microgranulates are disclosed which comprise hemispherical particles indented to form toroid-shaped beads. The microgranulates are free-flowing, non-dust forming, and are stable in handling.

Abstract: A titanium dioxide composition useful as the opacifier agent for vitreous enamels and fusion enamels comprises TiO.sub.2 predominantly in the form of isometric primary particles from 0.5 to 5.0 .mu.m in size, which are aggregated to predominantly spherolithic particles 1 to 100 .mu.m in diameter, with a BET surface of 1 to 4.5 m.sup.2 /g and an apparent density of 0.2 to 1.3 kg/1, is prepared by subjecting titanium dioxide hydrate having a BET surface of from 50 to 500 m.sup.2 /g to accelerated calcination at temperatures of 800.degree. to 1600.degree. C.

Abstract: Chromium oxide green in the form of donut-shaped, ring-shaped or tire-shaped particles having an internal diameter of from 0.01 to 0.5 mm and an external diameter of from 0.05 to 1.0 mm is prepared by spraying an aqueous chromium oxide green suspension through a liquid pressure nozzle into a spray dryer such that the suspension entering the drying space of the spray dryer is rotating.

Abstract: A process is disclosed for preparing iron oxide black pigments obtained by the nitrobenzene reduction process, wherein the iron oxide black is heated to 400.degree.-800.degree. C. in a slightly oxidizing atmosphere with optional milling. The pigments are useful for coloring plastics, coatings and building materials.

Abstract: A titanium dioxide composition useful as the opacifier agent for vitreous enamels and fusion enamels comprises TiO.sub.2 predominantly in the form of isometric primary particles from 0.5 to 5.0 .mu.m in size, which are aggregated to predominantly spherolithic particles 1 to 100 .mu.m in diameter, with a BET surface of 1 to 4.5 m.sup.2 /g and an apparent density of 0.2 to 1.3 kg/l, is prepared by subjecting titanium dioxide hydrate having a BET surface of from 50 to 500 m.sup.2 /g to accelerated calcination at temperatures of 800.degree. to 1600.degree. C.

Abstract: A process is disclosed for preparing dispersant-free iron oxide pigment granules by spraying or atomizing an iron oxide black pigment suspension and heating the resulting granules at a temperature of 400.degree.-800.degree. C. The granules are useful for coloring building materials such as concrete.

Abstract: Thermostable pigments for coloring stoving lacquers, coil coat lacquers, plastics, sand granulates, lime sandstone, enamel or ceramic glazes are zinc ferrite color pigments containing from 0.01 to 0.5% by weight of lithium.

Abstract: Needle shaped alloy pigment powders consisting essentially of iron, silicon and aluminum, with up to 1.0% by weight of chromium and one or both of cobalt or tin in amounts from 0.3 to 3% by weight of cobalt and from 0.1 to 5.0% by weight of tin, based in each case on the iron, are useful as the magnetic powders used in magnetic recording devices.

Abstract: Chrome green oxide useful, inter alia, as a coloring material and having a water number of 10 to 40 g/100 g is prepared by adding sulphonic acid compounds, polyphosphoric acid compounds, polyacrylic acid compounds or mixtures thereof, in quantities of from 0.1 to 2% by weight, to an aqueous suspension of chrome oxide green pigment having a BET surface area of from 1 to 20 m.sup.2 /g before drying, and then drying the suspension.

Abstract: Iron oxide black pigments useful as coloring pigments for lacquers and plastics are prepared by an improved process wherein finely divided iron oxide black suspensions obtained from the precipitation processor the aniline process are filtered, washed, dried and ground with the improvement in the process comprising grinding the dried iron oxide pigment in a jet mill with air as the grinding medium and with a water content of from about 1 to 6% by weight based on the iron oxide black pigment input to the process.

Abstract: A process for the production of rutile mixed-phase pigments comprising calcinating of a solid mixture of titanium dioxide or titanium oxide hydroxide with a dye-producing compound of a metal, in one or more directly heated, continuously operated rotary kilns, wherein in terms of material flow, air is introduced into the kiln atmosphere countercurrently to the direction of flow of the solids in the second half of the rotary kiln.

Abstract: A process for the production of rutile mixed-phase pigments comprising calcinating a solid mixture of titanium dioxide and/or titanium dioxide hydrate with a dye-producing metal compound in an indirectly heated rotary kiln supplied with air, wherein the titanium dioxide comprises an uncalcined, salt-free titanium dioxide having a specific BET surface of 50 to 500 m.sup.2 /g.

Abstract: In a rotary tubular kiln for carrying out gas-solids reactions, comprising an indirectly heated, rotatable reaction tube with inner baffles which is provided with charging and removing devices for solid and gas inlet and outlet lines, the improvement which comprises forming the baffles as a central tube which is sealed on both sides and runs along the total length of the kiln, and a spiral which is tightly connected to the central tube and also to the outer rotatable tube. Lifting blades are uniformly distributed along the inner periphery of the rotatable tube. The kiln is suitable for carrying out oxidation, reduction, chlorination, roasting, decomposition, catalytic, annealling and/or cooling processes, e.g. the conversion of hematite to magnetite or goethite to iron.

Abstract: Sensitive magnetic pigment particles enclosed in about 0.1 to 5% by weight of a polymeric material thereby preserving the pigment magnetic properties. Advantageously, the polymer, which serves as a packing, is at least one member selected from the group consisting of polycarbonates, polyacrylates, polymethacrylates, polyesters, polyethers, polyurethanes, polyvinyl compounds, polyvinylidene compounds and cellulose compounds. These are compatible with the matrices used to make magnetic tapes.

Abstract: A process for the production of an anisometric yellow-brown zinc ferrite pigment comprising homogeneously mixing zinc oxide having a specific BET surface of more than 2 m.sup.2 /g with needle-shaped .alpha.-FeOOH obtained from an iron salt solution by mixing with alkali and subsequently oxidizing in a nucleation and pigment growth stage, the FeOOH having a specific BET surface of about 15 to 25 m.sup.2 /g, an average needle width of about 0.025 to 0.125 .mu.m and an average needle length of about 0.2 to 0.6 .mu.m, annealing the mixture at a temperature of about 700.degree. to 1000.degree. C., cooling and grinding.

Abstract: Highly pure and highly color intensive black anisometric magnetite iron oxide pigment having an FeO content of from 26 to 29% by weight and manganese content of less than 0.1% by weight, said pigment further having a specific BET surface area of from 5 to 15 square meters per gram and being needle shaped particles with an average needle diameter of 0.1 to 0.2 .mu.m and an average needle length of from 0.6 to 0.8 .mu.m are produced by producing .alpha.-FeOOH particles by alkali precipitation of an iron salt solution with a nuclear formation stage oxidation and a pigment growth stage oxidation followed by reduction and passivation.

Abstract: A magnetic pigment consisting essentially of iron, having an X-ray crystallite size with the 110 reflex of from 14 to 22 nm, a coercive force from 55 to 88 kA/m and a switching field distribution of the oriented pigment particles of less than 0.55 is produced by precipitating an iron (II)-salt with a super-stoichiometric quantity of an aqueous alkali metal carbonate solution and oxidizing it to produce .alpha.-FeOOH, .gamma.-Fe.sub.2 O.sub.3, Fe.sub.3 O.sub.4 or betholoid iron oxides, subsequently reducing it to the metal, and providing the iron oxides or oxide hydroxides with an inorganic protection from sintering at the latest during reduction.

Abstract: In a rotary tubular kiln for carrying out gas-solids reactions, comprising an indirectly heated, rotatable reaction tube with inner baffles which is provided with charging and removing devices for solid and gas inlet and outlet lines, the improvement which comprises forming the baffles as a central tube which is sealed on both sides and runs along the total length of the kiln, and a spiral which is tightly connected to the central tube and also to the outer rotatable tube. Lifting blades are uniformly distributed along the inner periphery of the rotatable tube. The kiln is suitable for carrying out oxidation, reduction, chlorination, roasting, decomposition, catalytic, annealing and/or cooling processes, e.g. the conversion of hematite to magnetite or goethite to iron.

Abstract: Spherical agglomerates of surface-stabilized primary particles substantially consisting of iron, having a BET surface of about 5 to 50 m.sup.2 /g, measured on the agglomerate, in non-pyrophoric form and having a bulk density of about 0.5 to 2.0 kg/l and an agglomerate diameter of about 0.5 to 10 mm are produced by(a) reducing in dry phase particles consisting essentially of iron oxide,(b) intensively dispersing the particles in liquid phase,(c) coating the particles with an inorganic and/or organic coating optionally containing corrosion inhibitors,(d) separating the particles from the liquid phase by evaporating the volatile components with a continuously rotating and simultaneously tumbling movement, and(e) subjecting the resulting granulates to a thermal treatment. The particles are especially useful for the production of magnetic recording media.