Abstract: The invention relates to a method for the surface treatment of a titanium dioxide with aluminum phosphate and hydrous aluminum oxide that leads to pigments with improved greying resistance, while simultaneously maintaining good brightness and opacity. The method is characterized in that phosphoric acid is initially added to a TiO2 suspension with a pH value of at least 8, in which context the pH value drops to 3 or below. An alkaline aluminum compound is subsequently added, in which context the pH rises to at least 5, after which an acid aluminum compound is added, as a result of which a pH value of 4.5 to 7 is obtained. The pigment manufactured by the method according to the invention is eminently suitable for use in decorative laminating paper.

Abstract: The invention relates to a method for the surface treatment of a titanium dioxide with aluminium phosphate and hydrous aluminium oxide that leads to pigments with improved greying resistance, while simultaneously maintaining good brightness and opacity. The method is characterised in that phosphoric acid is initially added to a TiO2 suspension with a pH value of at least 8, in which context the pH value drops to 3 or below. An alkaline aluminium compound is subsequently added, in which context the pH rises to at least 5, after which an acid aluminium compound is added, as a result of which a pH value of 4.5 to 7 is obtained. The pigment manufactured by the method according to the invention is eminently suitable for use in decorative laminating paper.

Abstract: The invention relates to a rutile titanium dioxide pigment for use in decorative laminating papers that yields higher opacity of the papers compared to the prior art, as well as a method for its manufacture. The pigment displays a surface coating that contains aluminum phosphate, aluminum oxide, silicon oxide and titanium oxide. The silicon oxide is precipitated in fluffy form. The coated particles display a BET value of at least 15 m2/g. The manufacturing method is characterized in that an aluminum and a phosphorus component are first added to a TiO2 suspension. Thereafter, an alkaline silicon component, an acid-reacting titanium component and, optionally, a further pH-regulating component are added, the pH value being set in the range from 4 to 9 in this context.

Abstract: A method of predicting photostability of coatings with various dopants on titanium dioxide pigment particles is disclosed. Calculations of the density of states show that a doped coating which reduces the density of states near the band edge or increases the density of states within the band gap of the pigment particles increases the photostability of the doped pigment.

Abstract: A method for marking titanium dioxide pigment particles, as well as a method for identifying and verifying products via the marked titanium dioxide pigment particles contained in these products. The marker substance(s) is/are added during titanium dioxide production, preferably during surface treatment, drying or steam-milling. Particularly suitable as marker substances are the lanthanides, yttrium, zinc, molybdenum, tungsten, germanium, tin and scandium. The method is used to verify authentic product, to identify product forgeries (product piracy), to track distribution channels, or to identify the pigment used in order to counter unjustified complaints. It can be used in the product segments: fibres for textiles, papers for documents, pharmaceuticals, and also for plastics and coatings.

Abstract: A coated titanium dioxide pigment with good opacity and simultaneously good retention for use in decorative laminating paper characterized by a surface coating containing aluminum oxide phosphate and attached hollow bodies, e.g., hollow microbodies. A manufacturing method is characterized in that an aluminum containing component and a phosphorus containing component are first added to a TiO2 suspension, during which time the pH value does not drop below 10. The hollow bodies are subsequently added, followed by addition of at least one acidic component, as a result of which the pH value of the suspension is lowered to the range from about 4 to 9. In an alternative embodiment of the method, the suspension has a pH value of under 4 at the time of addition of the aluminum containing component and a phosphorus containing component.

Abstract: A coated titanium dioxide pigment with good opacity and simultaneously good retention for use in decorative laminating paper characterized by a surface coating containing aluminium oxide phosphate and attached hollow bodies, e.g., hollow microbodies. A manufacturing method is characterized in that an aluminium containing component and a phosphorus containing component are first added to a TiO2 suspension, during which time the pH value does not drop below 10. The hollow bodies are subsequently added, followed by addition of at least one acidic component, as a result of which the pH value of the suspension is lowered to the range from about 4 to 9. In an alternative embodiment of the method, the suspension has a pH value of under 4 at the time of addition of the aluminium containing component and a phosphorus containing component.

Abstract: A method of predicting photostability of coatings with various dopants on titanium dioxide pigment particles is disclosed. Calculations of the density of states show that a doped coating which reduces the density of states near the band edge or increases the density of states within the band gap of the pigment particles increases the photostability of the doped pigment.

Abstract: The invention relates to a rutile titanium dioxide pigment for use in decorative laminating papers that yields higher opacity of the papers compared to the prior art, as well as a method for its manufacture. The pigment displays a surface coating that contains aluminium phosphate, aluminium oxide, silicon oxide and titanium oxide. The silicon oxide is precipitated in fluffy form. The coated particles display a BET value of at least 15 m2/g. The manufacturing method is characterized in that an aluminium and a phosphorus component are first added to a TiO2 suspension. Thereafter, an alkaline silicon component, an acid-reacting titanium component and, optionally, a further pH-regulating component are added, the pH value being set in the range from 4 to 9 in this context.

Abstract: A method of predicting photostability of coatings with various dopants on titanium dioxide pigment particles is disclosed. Calculations of the density of states show that a doped coating which reduces the density of states near the band edge or increases the density of states within the band gap of the pigment particles increases the photostability of the doped pigment.

Abstract: The invention relates to a jet mill of modular design for the comminution of powdery materials. An inner pulverizing casing made entirely of wear-resistant material is freely mounted in an outer casing pressure vessel.

Abstract: The invention relates to a titanium dioxide pigment mixture comprising a pigment having high greying stability (pigment type A) and a pigment having increased SiO2 and Al2O3 content in flaky precipitation (pigment type B). Said mixture provides, for example in paper, a high level of opacity for sufficient greying stability. If necessary, the light-fastness of the paper can be further increased by means of known production-conditioned measures on pigment type B.

Abstract: The invention relates to a method for the surface treatment of a titanium dioxide that leads to pigments with improved retention and improved opacity, where consistently high opacity can be obtained using less pigment. The method is characterised in that an aluminium component and a phosphorus component are first added to a TiO2 suspension, during which process its pH value does not drop below 10. The pH value of the suspension is subsequently lowered to below 9 by adding an acid component. The pigment produced by the method according to the invention is eminently suited to use in decorative laminating paper.

Abstract: The invention relates to a jet mill of modular design for the comminution of powdery materials.An inner pulverizing casing made entirely of wear-resistant material is freely mounted in an outer casing pressure vessel.

Abstract: A method for preparing high quality pigments having improved wettability, dispersibility and gloss characteristics, which method comprises grinding a pigment base material in a jet mill in the presence of an organic grinding aid, recovering ground pigment particles having a first organic layer, comprising the organic grinding aid, and treating the recovered pigment particles with an organic material, forming a second organic layer on the pigment particles, for improving the wettability, dispersibility and gloss characteristics of the treated pigment particles. Titanium dioxide, both untreated and pretreated with an inorganic coating, may be processed according to the method herein to yield high quality titanium dioxide pigment having improved wettability, dispersibility and gloss characteristics. The titanium dioxide pigment is particularly suitable for use in water-thinnable paint systems.

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: 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.