Abstract: A colored titanium flake having a flat, smooth surface, the flake including a coherent oxide layer formed on its surface, and the thickness of the coherent oxide layer being 100 to 1000 .ANG., a process for preparing the colored titanium flakes and a resin composition containing the colored titanium flakes.

Abstract: The invention provides a method for synthesizing a titanium oxide-containing film comprising the following steps:(a) preparing an aqueous solution of a titanium chelate with a titanium molarity in the range of 0.01M to 0.6M.(b) immersing a substrate in the prepared solution,(c) decomposing the titanium chelate to deposit a film on the substrate.The titanium chelate maybe decomposed acid, base, temperature or other means. A preferred method provides for the deposit of adherent titanium oxide films from C2 to C5 hydroxy carboxylic acids. In another aspect the invention is a novel article of manufacture having a titanium coating which protects the substrate against ultraviolet damage. In another aspect the invention provides novel semipermeable gas separation membranes, and a method for producing them.

Abstract: Flame-hydrolytically produced titanium dioxide mixed oxide having a BET surface of 10 to 150 m.sup.2 /g and 1 to 30% by weight aluminum oxide or 1 to 30% by weight silicon dioxide is produced by evaporating aluminum chloride or silicon tetrachloride, transferring the evaporated aluminum chloride or silicon tetrachloride, together with an inert gas, into the mixing chamber of a burner, mixing them with hydrogen, air and gaseous titanium tetrachloride, burning the resulting 4-component mixture in the reaction chamber of the burner, and separating the titanium dioxide mixed oxide from the gaseous reaction products.

Abstract: A photochromic ultra-violet ray shield material principally composed of titanium oxide particles, which have a specific surface area of 25 m2/g or above and also have .DELTA.E=5.ltoreq.A (discoloration degrees) and B (at restoration)<.DELTA.E=3, a method of manufacturing the same and a skin external preparation using the same. Both photochromic property and excellent ultra-violet ray shield effect are obtained.

Abstract: A rutile mixed metal oxide pigment can be prepared by calcining a rutile ore with a transition metal oxide. The rutile mixed oxide pigment can be dispersed in an emulsion to produce a paint or coating or the pigment can be combined with a network former and network modifier to produce a ceramic glaze.

Abstract: The present invention relates to a process for the production of titanium dioxide pigments and the use thereof.

Abstract: This invention relates to a filtering cosmetic composition characterized in that it is comprised, in a cosmetically acceptable carrier, at least one nanopigment of metal oxides selected amongst titanium, zinc, cerium, zirconium, iron oxides or mixtures thereof, having an average diameter lower than 100 nm, and at least one polymer carrying at least one ultraviolet absorbing group selected amongst liposoluble polymers having a hydrocarbonated structure and the polymers of siloxanic structure and such compositions are useful for the protection of human epidermis and hair against UV radiation or as make-up composition.

Abstract: This invention provides a process for making titanium dioxide pigment, wherein an aqueous slurry of hydrous oxide surface-treated TiO.sub.2 particles is subjected to media milling. The TiO.sub.2 particles are surface-treated with a coating comprising a hydrous oxide such as silica and/or alumina, and the slurry is filtered prior to media milling. The milled slurry is dried and the dried product is fluid-energy milled to produce TiO.sub.2 pigment having good particle size distribution. The TiO.sub.2 pigments may be used to make coating formulations having high gloss.

Abstract: There are disclosed stabilized Ti-Sn-O nanoclusters formed by complexing Ti-Sn-O nanoclusters with a salt of an alpha-hydroxy acid and also complexed nanoclusters with increased charge transfer interaction formed by annealing the complexed nanoclusters. Also disclosed are compositions for protection against ultraviolet radiation in which the nanoclusters are utilized with the usual topical carriers in an amount to give the level of sun protection factor (SPF) desired. Further disclosed is the method of making the nanoclusters involving acid hydrolyzing a titanium alkoxide and then reacting the hydrolyzed alkoxide with a tin halide.

Abstract: Essentially mesoporous titanium oxide materials, having an average pore diameter of no more than about 100 .ANG. (e.g., from about 20 .ANG. to about 50 .ANG.) and an average surface area of no less than about 300 m.sup.2 /gm, preferably no less than about 500 m.sup.2 /gm are disclosed which optionally can contain an effective amount of at least one transition metal (e.g., a rare earth metal, iron, or the like) for stabilization. These materials can be formed by treating a titanium source, which is derived from a titanium alkoxide, in an organic-aqueous solution, with an organic structure directing agent (e.g., higher alkyl amine, optionally in the presence of an alcohol cosolvent) to form meso-sized micelles and hydrothermally treating the resulting composition.

Abstract: There is disclosed a process for producing premium grades of metal oxide comprising (1) providing wet or dried hydrous metal oxide containing high levels (e.g., 2%-10% chloride) of halogen contamination, (2) treating the contaminated metal oxide with a base in gas phase, which base is volatile at .ltoreq.900.degree. C., at a final temperature of between 750.degree. C. to no greater than 900.degree. C. wherein the temperature is brought to the final temperature in increments of about 25.degree. C., until gas exiting shows no additional evolution of a halogen conjugated acid, and (3) exposing the treated metal oxide to air or oxygen at a temperature of 500.degree. to 600.degree. C. to convert any metal nitrides or oxynitrides present to metal oxide, wherein the metal oxide is selected from the group consisting of Ta.sub.2 O.sub.5, niobium oxide, hafnium oxide, zirconium oxide and titanium oxide. The inventive process yields a premium grade, high active surface area .beta.-Ta.sub.2 O.sub.

Abstract: A TiO.sub.2 hydrogel and method of preparation therefor is disclosed: TiO.sub.2 particles ranging in size from at least about 50 nm to about 150 nm wherein the particle is about 20% to about 90% anatase are disclosed. Topical sunscreen compositions, which comprise 1% to about 15% anatase/amorphous TiO.sub.2 are also disclosed. This composition provides UVA and UVB protection without concomitant dulling or discoloring the skin. The composition also has enhanced stability, is invisible, is easy to apply in an even manner and resists discoloration (or "color-changing") or decomposition on the shelf or on the skin.

Abstract: The present invention relates to neutral titanium dioxide sols which have been stabilized with hydroxycarboxylic acids or derivatives thereof and are treated with metal ions, inorganic anions, complexing agents and/or oxidizing agents to improve the photostability.

Abstract: The invention relates to a process for the silylation of very finely divided inorganic oxides, in which the very finely divided inorganic oxides are treated with at least one silylating agent which is relatively nonvolatile in the temperature range of the overall process, with the proviso that the relatively nonvolatile silylating agent is admixed with the very finely divided inorganic oxides as a liquid, in the form of a very finely atomized aerosol. Furthermore, the invention relates to a highly apolar, pyrogenic silica prepared by this process.

Abstract: A method for producing titanium dioxide from an iron-containing titanium ore concentrate includes heating the ore concentrate in the presence of a reducing agent to provide a sintered reaction product including a titanium salt of the alkali metal and metallic iron. The titanium salt of the alkali metal is decomposed by addition of water to provide titanium dioxide. For ilmenite (FeTiO.sub.3), preferred alkali metal salts include carbonates, and formates of sodium and potassium. The titanium metal salt so formed is sodium or potassium meta titanate (K.sub.2 TiO.sub.3 or Na.sub.2 TiO.sub.3) depending on the alkali metal used. Suitable reducing agents include hydrogen, methane, carbon monoxide, or solid carbon. Metallic iron may be magnetically separated from ground reaction product or from a slurry formed by addition of water to the reaction product, the slurry including the titanium dioxide.

Abstract: Flame-hydrolytically produced titanium dioxide mixed oxide having a BET surface of 10 to 150 m.sup.2 /g and 1 to 30% by weight aluminum oxide or 1 to 30% by weight silicon dioxide is produced by evaporating aluminum chloride or silicon tetrachloride, transferring the evaporated aluminum chloride or silicon tetrachloride, together with an inert gas, into the mixing chamber of a burner, mixing them with hydrogen, air and gaseous titanium tetrachloride, burning the resulting 4-component mixture in the reaction chamber of the burner, and separating the titanium dioxide mixed oxide from the gaseous reaction products.

Abstract: A process for recovering metal oxides from waste water using anionic and cationic polymeric emulsions is disclosed. The treated metal oxides may then be recovered using a clarification step. Steps requiring the adjustment of pH based on the use of acids and base are thereby eliminated.

Abstract: A ceramic mirror having a surface flatness of no more than 1 .mu.m and/or a centerline average height of no more than 1 nm as measured by the laser interference method, is made from a titanium oxide powder having an average particle diameter of 0.5 .mu.m and a minimum purity of 99.8% by weight. The mirror also has a maximum amount of irregular reflection of incident light not exceeding 5% when the angle of projection is between 0.degree. and 90.degree. as measured by a colorimeter and is made by the process including forming a titanium oxide powder having a maximum average particle diameter of 0.5 .mu.m and a minimum purity of 99.8 wt. %, compacting the titanium oxide powder by cold isostatic pressing to produce a compact, sintering the compact of titanium oxide powder in air at a temperature of 1000.degree. C.-1300.degree. C. to produce a ceramic body, hot isostatic pressing the ceramic body after the sintering in an inert atmosphere at 800.degree. C.-1500.degree. C. under a minimum pressure of 500 kg/cm.

Abstract: A process for preparing anatase titanium dioxide by precipitating hydrous titanium oxide in the absence of added nuclei from a solution of titanium sulphate containing the equivalent of 200 to 300 grams TiO.sub.2 per liter and having an acid to titanium ratio in the range 1.6:1 to 2.2:1, the precipitation being induced by the addition of 5 to 35 parts water per 100 parts titanium sulphate solution. The hydrous titanium oxide is calcined in the presence of an amount of potassium compound equivalent to between 0.20 and 0.60 weight percent calculated as K.sub.2 O based on TiO.sub.2 and between 0.15 and 0.55 weight percent phosphorus calculated as P.sub.2 O.sub.5 based on TiO.sub.2. The hydrous titanium oxide is subjected to calcination in a process having a specified thermal profile. The product of the process is anatase titanium dioxide having an average crystal size larger than conventionally prepared anatase. Said product is easily milled to form a product with a high single crystal fraction.

Abstract: The present invention provides a method for producing ceramic fine particles comprising the steps of supplying gaseous starting materials or starting material droplets to a reaction space arranged in an annular portion between inner and outer cylinders of a coaxial, double-cylinder reaction apparatus, the reaction apparatus having a stationary outer cylinder and a rotatable inner cylinder; and subjecting the gaseous starting materials or the starting material droplets to reaction in the reaction space while rotating the inner cylinder. Also, the present invention provides a production apparatus used therefor.

Abstract: Alkali-metal bisulfate is employed in a non-polluting and economically-feasible system for producing titanium dioxide pigment from titanium mineral or slag with recycling of alkali-metal bisulfate and ammonia.

Abstract: In the preparation of a suspension with a high content of titanium dioxide, which has been produced according to the chloride process, a finely divided titanium dioxide is slurried, in unflocculated condition without use of a dispersing agent, dechlorinated and then filtered. The content of multivalent anions can be controlled in the slurry before the filtration through suitable dechlorinating agents, particularly hydrogen peroxide and/or sodium hydrogen sulfite, and thereby the solid content in the filter cake and the consistency of the filter cake are advantageously influenced. If, on one hand, no or only few multivalent anions are present, a thixotropic filter cake with a high solids content is obtained in a pressure filtration. The filter cake is converted into a titanium dioxide suspension with a high solids content through feeding into a titanium dioxide suspension to which a dispersing agent has been added.

Abstract: Dendrite or asteroidal titanium dioxide micro-particles having a length of 0.2 to 0.5 .mu.m, a thickness of 0.05 to 0.1 .mu.m, and a specific surface area of 20 to 130 m.sup.2 /gram, are produced by treating hydrated titanium oxide particles with an alkali, mixing instantaneously the resulting reaction product with an amount of hydrochloric acid in a ratio of 1 to 4 mols of hydrochloric acid to one mol of the titanium oxide in the reaction product to effect a reaction, then aging under heat at 85.degree. C. or higher, and then drying or, if necessary, firing after the drying, and subsequently may be coated with at least one from oxides and hydrated oxides of elements selected from aluminum, silicon, titanium, zirconium, tin and antimony to improve the dispersibility and resistance to light of the particles, or may be coated with tin oxide containing antimony or indium oxide containing tin to make the particles electroconductive.

Abstract: A titanium oxide hydrolysate slurry prepared by the sulfate process is treated with either an alkali metal hydroxide or an alkali metal carbonate to solubilize the sulfur bound to the titanium at a temperature of from 60.degree. C. to 120.degree. C. and the slurry is treated with an organic acid to remove the alkali metal compounds present. This process produces titanium oxide hydrolysate of high purity.

Abstract: A novel use of two specific neopentyl glycol diesters as wetting, dispersing, spreading and deterging agents for micronized TiO.sub.2, ZnO and other pigments is introduced. These esters, neopentyl glycol di-2-ethyl hexanoate and neopentyl glycol di-isostearate, are used in varying combinations and may also be used with an emulsifying agent for a water dispersible pigmented make-up cleaner composition.

Abstract: Flame-hydrolytically produced titanium dioxide mixed oxide having a BET surface of 10 to 150 m.sup.2 /g and 1 to 30% by weight aluminum oxide or 1 to 30% by weight silicon dioxide is produced by evaporating aluminum chloride or silicon tetrachloride, transferring the evaporated aluminum chloride or silicon tetrachloride, together with an inert gas, into the mixing chamber of a burner, mixing them with hydrogen, air and gaseous titanium tetrachloride, burning the resulting 4-component mixture in the reaction chamber of the burner, and separating the titanium dioxide mixed oxide from the gaseous reaction products.

Abstract: An apparatus provides high temperature and short residence time conditions for the production of nanoscale ceramic powders. The apparatus includes a confinement structure having a multiple inclined surfaces for confining flame located between the surfaces so as to define a flame zone. A burner system employs one or more burners to provide flame to the flame zone. Each burner is located in the flame zone in close proximity to at least one of the inclined surfaces. A delivery system disposed adjacent the flame zone delivers an aerosol, comprising an organic or carbonaceous carrier material and a ceramic precursor, to the flame zone to expose the aerosol to a temperature sufficient to induce combustion of the carrier material and vaporization and nucleation, or diffusion and oxidation, of the ceramic precursor to form pure, crystalline, narrow size distribution, nanophase ceramic particles.

Abstract: The invention relates to a method of preparing microcrystalline titanium dioxide, in which a) the solid titanium dioxide hydrate is treated with a base, b) the precipitate treated with the base is treated with hydrochloric acid, and c) the precipitate treated with the base and the hydrochloric acid is neutralized. It has been noted that useable rutile crystals, a more appropriate crystal size and crystal size distribution and that chemicals can be saved if as the final hydrochloric acid content of the stage a) is adjusted a lower value than usually, being about 8 to 25 g/liter, for the precipitation of microcrystalline titanium dioxide. Hereby the neutralization of the stage c) can also be carried out by raising the pH to a lower value than usually, i.e. the value about 4.0 to 6.0.

Abstract: A heat treatment method heats an oxide optical crystal in an oxygen atmosphere containing ozone to improve the light absorption characteristics of the oxide optical crystal so that the light absorption of the oxide optical crystal with light in wavelength bands other than light in wavelength bands with which the oxide optical crystal exerts the intrinsic absorption is reduced to the least possible extent. Guided-optical-wave propagation devices and optical devices, such as optical isolators, optical recording media and second harmonic generators, employing the oxide optical crystal having these improved absorption characteristics, operate at a high efficiency.

Abstract: The production of titanium dioxide by the sulphate process generates waste substances such as the wash filtrates, which are formed in the washing of titanium dioxide hydrate, and waste gases which contain sulphur dioxide. In this improved process the wash filtrate is used to remove the sulphur dioxide from the waste gas while the sulphuric acid content of the wash filtrate is raised and the sulphuric acid-containing process solution thus obtained is used within the scope of the titanium dioxide production process. The waste gas and the wash filtrate are passed countercurrently through a series of several washing steps and are contacted with each other by introducing the wash liquid into the waste gas in a finely divided form in scrub towers. The sulphuric acid content of the washing fluid is stepwise changed from washing stage to washing stage. The sulphur dioxide content of the waste gas is reduced to values that may be discharged into the ambient atmosphere.

Abstract: A finely divided chloride process titanium dioxide prepared without the use of a dispersing agent. The slurry is dewatered via filtration, and the resulting filter cake is made flowable with an anionic dispersing agent. In order to attain a filter cake with very high solids content, the slurry should contain no, or only very few, multivalent anions. The conditions regarding the content of multivalent anions of the slurry are achieved by selection of suitable dechlorinating agents, especially hydrogen peroxide. The filter cake is thixotropic and is made flowable by the fact that it is put into the "diluted" dispersing agent, especially into a part of the titanium dioxide suspension to which the required quantity of dispersing agent has previously been added. Titanium dioxide suspensions with solids content of approximately 78% are thereby obtained and are of particular use in the paper industry.

Abstract: Synthetic rutile is prepared from titaniferous slags containing alkaline-earth metal impurities, such as magnesium oxide, by a method comprising contacting the slag with chlorine at a temperature of at least about 800.degree. C., and then leaching the chlorine-treated slag with hydrochloric acid at a temperature of at least about 150.degree. C.

Abstract: Method is provided for preparing PbO-based ceramics by mixing metal cations in alkanolamines and then adding the mixture to lead carboxylates in alcohol, to obtain ceramic solutions or gels therefrom. The metal cations are sourced from metal alkoxides, chelates and salts and include metals of Ti, Zr and La. The above solutions and gels can be employed to form PbO-based powders, fibers and films, e.g. films of PZT and PLZT, which find electrical and optical applications such as ferroelectric memory and dielectric waveguides. The invention resides in the above method and resulting PbO ceramics which have e.g. films of considerably higher dielectric constants than previously known in the art.

Abstract: Pressed parts based on pyrogenically produced titanium dioxide with the following physico-chemical characteristics:______________________________________ Outer diameter 0.8-15 mm BET surface according <1-20 m.sup.2 /g to DIN 66 131 Pore volume 0.01-0.29 cm.sup.3 /g Pore distribution no pores <10 nm at least 90% of the pores in a range of 10-80 nm Breaking strength 30-500 N/pressed part TiO.sub.2 phase rutile 100% Composition >99.5% TiO.sub.2 ______________________________________They are produced by mixing pyrogenically produced titanium dioxide with urea, graphite and water, compacting the mixture, optionally drying the resulting mass at 80.degree. C. to 120.degree. C. comminuting, subsequently extruding or tabletting to produce pressed parts and tempering the pressed parts at a temperature of 710.degree. C. to 1000.degree. C. for a period of 0.5 to 6 hours. The pressed parts can be used as catalyst or catalytic carrier.

Abstract: This invention provides a three dimensional inorganic oxide structure comprising a myriad of cavities interconnected by holes having a narrow pore size distribution, in which the diameters of the cavities is in the range from 1 to 50 .mu.m and that of the holes in the range 1 to 10 .mu.m and in which the pore volume in the range 1 to 10 .mu.m is at least 2 cc/g and in which the inorganic oxide is selected from alumina, silica, titania, zirconia and mixtures thereof and a process for the preparation of such structures.

Abstract: Carbonic diesters containing at least one aromatic ester group can be prepared from carbonic diesters containing at least one aliphatic ester group by transesterification using a phenol, titanium dioxide having a surface area of at least 20 m.sup.2 /g as determined by the BET method being used as catalyst.

Abstract: A titanium dioxide production method, a novel titanium dioxide product produced by the inventive titanium dioxide production method, a method for producing a plastic product using the novel titanium dioxide product, and a novel plastic product formed by the inventive plastic product production method. The inventive titanium dioxide production method comprises the steps of: (a) forming a mixture comprising a titanium dioxide material in a liquid medium; (b) wet milling the titanium dioxide material in the liquid medium; (c) after step (b), reducing the pH of the mixture to a value not exceeding 4.0; (d) after step (c), adding an effective amount of a base to the mixture to cause the titanium dioxide material to flocculate; (e) removing the flocculated titanium dioxide material from the mixture; and (f) washing the titanium dioxide material. The titanium dioxide material used in step (a) is an agglomerated titanium dioxide material which has been produced by a reaction process.

Abstract: Disclosed is a process for producing a titanium dioxide pigment used for a resin-coated paper type photographic support, comprising the following steps:(a) a step of adding at least one alkaline earth metal compound in an amount of 0.01-2.0% by weight in terms of a metal oxide based on the titanium dioxide before calcination step and(b) an acid-washing step of washing the titanium dioxide at acidic state after the calcination step and before a step of surface treatment with a hydrated metal oxide,and wherein particle size of the titanium dioxide pigment is 0.110-0.150 .mu.m shown by number-average diameter obtained by measuring the diameter in a certain direction using an electron microscope.A photographic support which comprises the above titanium dioxide pigment is also disclosed.Occurrence of die lip stain and microgrit are substantially restrained in this photographic support and a photographic material made of it shows improved image sharpness.

Abstract: A process is provided for the synthesis for metal oxides of high specific surface area and high porosity which are particularly useful as catalyst supports. The process comprises forming a mixture of a salt of at least one metal and a molten salt medium comprising at least one alkali metal salt having an oxidizing effect, maintaining this mixture at the reaction temperature for the time necessary to convert the salt to oxide and thereafter isolating the metal oxide formed.

Abstract: A process for the preparation of titanium dioxide by the sulphate process in which titanium raw materials are decomposed with sulphuric acid, the resulting titanyl sulphate is hydrolyzed, the waste acid is separated from the hydrolyzate and evaporated to a concentration of 60 to 70%, sulphuric acid is separated from the solid metal sulphates, and the sulphuric acid which has been concentrated by evaporation is used again for the decomposition of the titanium raw material, the improvement wherein the 60 to 70% sulphuric acid is concentrated to 70 to 80% H.sub.2 SO.sub.4 in a further evaporation stage and the concentration of a part of this sulphuric acid is raised to a concentration of 98 to 99% H.sub.2 SO.sub.4 by the absorption of SO.sub.3 and then used together with the remainder of the above-mentioned 70 to 80% sulphuric acid for the decomposition of titanium raw materials.

Abstract: A titanium oxide film consists of a mixture of titanium monoxide (TiO), titanium dioxide (TiO.sub.2), titanium trioxide (Ti.sub.2 O.sub.3), titanium pentoxide (Ti.sub.3 O.sub.5) and other titanium oxides which are expressed as Ti.sub.n O.sub.2n-1 is an integer from 4 to 10. Average content of oxygen in the film is from 51 to 59 atom percent.

Abstract: Titaniferous solid containing titanium (IV) oxide, for example ilmenite, is reacted with silicon tetrafluoride gas at 800.degree. C. or more and at a pressure of at least 1 atmosphere to produce titanium tetrafluoride vapor and silica. The vapor is rapidly removed from the reaction zone, preferably by rapid cooling to solid titanium tetrafluoride, at a sufficient distance from the reaction zone so as not to quench the reaction. The titanium tetrafluoride may be hydrolysed to produce titanium dioxide and hydrogen fluoride which is combined with silica to regenerate silicon tetrafluoride. It is preferred to pretreat the titaniferous solid by grinding and then roasting at 700.degree. C. to 750.degree. C. in air. Products of the reaction may be separated and purified by condensation and resublimation.

Abstract: A ceramic sintered body and a method for manufacturing the same in which the body includes a first material having at least one of a precursor and a metastable material of the final sintered body and a second material morphologically related to the first material and added to the first material to affect transformation of said first material into the desired crystalline form of the ceramic sintered body, in which method transformation of a metal oxide compound from one phase to another, where the compound has a high activation energy and is confronted with a high nucleation energy barrier to the transformation, produces the body and includes the steps of making a mixture by bringing a multiplicity of particles of the compound into intimate contact with the multiplicity of nucleation particles having crystallographically related structure to act as nuclei for the transformation and sintering the resulting mixture to transform the compound from one phase to another by nucleation and growth, independently of gro

Abstract: An organic titanium compound and an organic compound which can react with the organic titanium compound, preferably a titanium tetraalkoxide and/or it derivative and methanol, are reacted in gas phase and the obtained product is hydrolyzed to give nearly real spherical, fine particle titanium oxide with no agglomeration and of mono dispersion.

Abstract: The iron content of the TiO.sub.2 -containing precursor is subjected to a direct reduction to effect a metallization of at least 90%. The reduced product is separated into magnetic and nonmagnetic fractions by magnetic separation. To oxidize the metallic iron, the magnetic fraction is subjected to an oxidation in an acid medium with agitation at a pH value below 2, under a pressure of 12 to 24 bars, and at a temperature from 150.degree. to 210.degree. C. with a supply of an oxygen-containing gas that contains at least 90% oxygen. When the suspension has been pressure-relieved, the hematite which has been formed is separated from the TiO.sub.2 concentrate.

Abstract: A process for calcining a filter cake in a directly heated rotary kiln wherein part of the filter cake is separated from the entire mass of filter cake, the separated portion is predried and recombined with the remainder portion and the combined predried and remainder portion is calcined. The filter cake can be inorganic solids such as oxides of titanium, chromium (III), zinc and iron.

Abstract: The present invention provides novel titanium dioxide aggregates especially suitable for an electrophotographic photosensitive material. This titanium dioxide aggregates comprise sintered aggregates of fine primary particles and have a rutile type crystal structure and an oil absorption of 35-65. This titanium dioxide aggregates which are treated with a mineral acid is also provided. There is also provided an electrophotograpic photosensitive material which contains such titanium dioxide in a photosensitive layer.

Abstract: There is provided a method of producing titanium oxides which comprises: admixing an aqueous solution of titanium tetrachloride with sulfuric acid in a molar ratio of sulfuric acid to titanium tetrachloride of at least 0.5 adding an alklai to the resultant solution to produce titanium hydroxide; and drying and calcining the titanium hydroxide. A further method is provided which comprises: adding a solution of an alkali to an aqueous solution of titanium tetrachloride having a concentration of not more than 2.5 moles/l at temperatures of not less than 50.degree. C., thereby to substantially thermally hydrolyze the titanium tetrachloride and to produce titanium hydroxide; and drying and calcining the titanium hydroxide.

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: A process for the production of a suspension of nuclei has been developed in which an aqueous mixture of titanium tetrachloride, aluminium ions and hydroxyl ions is cured at at temperature of from 50.degree. to the boiling point. The pH of the suspension before or after curing has a value of from 6.5 to 10.5. The aqueous mixture is prepared by mixing a solution of titanium tetrachloride with a solution of a base, e.g. sodium hydroxide and aluminium hydroxide.When used to nucleate hydrolysis in the "sulphate" process a large crystal size anatase pigment is produced.