Abstract: Aqueous dispersion containing a hydrophilic metal oxide powder comprising a metal oxide and a surface modification of the metal oxide, wherein a) the metal oxide is selected from the group consisting of TiO2, ZrO2, SiO2, Al2O3, Fe2O3, Fe3O4, Sb2O3, WO3, CeO2 and mixed oxides thereof and b) the surface modification b1) comprises silicon atoms and aluminum atoms and b2) the silicon atoms are at least partly bonded to a hydrocarbon radical via a C atom and b3) the Al/Si molar ratio of the surface modification is 1:2-1:20.

Abstract: Method of obtaining mineral oil, comprising the steps of: providing a fluid comprising surface-modified silica particles, introducing this fluid into a mineral oil deposit via a first well in contact with this mineral oil deposit, recycling a mixture comprising the fluid and mineral oil via the first well or a further well and separating the mineral oil from the mixture, wherein the fluid comprises surface-modified nanostructured silica particles in an aqueous phase, A) the surface modified silica particles a) being mixed aluminium-silicon oxide, where the mixed oxide component is also part of the particle surface, and b) the surface modification comprises a hydrocarbon radical which is interrupted by one or more heteroatoms and comprises a silicon atom is bonded to a carbon atom of the hydrocarbon radical, the surface modification being selected from the group consisting of Si—(CH2)n—Ym—R, where Si is the Si atom which is bonded via a C atom to a hydrocarbon radical, and n=1, 2 or 3 and m=0 or 1 R is a ra

Abstract: Dispersion comprising particles of a surface-modified, hydrophilic silica, where A) the particles of the surface-modified, hydrophilic silica comprise an aluminium atom and a hydrocarbon radical, a) the aluminium atom is bonded via an oxygen atom to a silicon atom of the particle surface, b) the hydrocarbon radical comprises a silicon atom which is bonded to a carbon atom of the hydrocarbon radical, c) possess an average particle diameter d50 in the dispersion of 40-200 nm, preferably 60-150 nm, and B) the pH of the dispersion is 8 or more.

Abstract: An aqueous dispersion comprising a surface-modified hydrophilic mixed oxide powder comprising silicon and aluminum and water, characterized in that a) the surface of the particles has Si and Al atoms and b) the surface modification has an Si atom bonded to a hydrocarbon radical via a C atom, and c) the carbon content of the surface-modified mixed oxide powder is 3-25% by weight.

Abstract: Dispersion comprising particles of a surface-modified, hydrophilic silica, where A) the particles of the surface-modified, hydrophilic silica comprise an aluminium atom and a hydrocarbon radical, a) the aluminium atom is bonded via an oxygen atom to a silicon atom of the particle surface, b) the hydrocarbon radical comprises a silicon atom which is bonded to a carbon atom of the hydrocarbon radical, c) possess an average particle diameter d50 in the dispersion of 40-200 nm, preferably 60-150 nm, and B) the pH of the dispersion is 8 or more.

Abstract: Method of obtaining mineral oil, comprising the steps of: providing a fluid comprising surface-modified silica particles, introducing this fluid into a mineral oil deposit via a first well in contact with this mineral oil deposit, recycling a mixture comprising the fluid and mineral oil via the first well or a further well and separating the mineral oil from the mixture, wherein the fluid comprises surface-modified nanostructured silica particles in an aqueous phase, A) the surface modified silica particles a) being mixed aluminium-silicon oxide, where the mixed oxide component is also part of the particle surface, and b) the surface modification comprises a hydrocarbon radical which is interrupted by one or more heteroatoms and comprises a silicon atom is bonded to a carbon atom of the hydrocarbon radical, the surface modification being selected from the group consisting of Si—(CH2)n—Ym—R, where Si is the Si atom which is bonded via a C atom to a hydrocarbon radical, and n=1, 2 or 3 and m=0 or 1 R is a ra

Abstract: Aqueous dispersion containing a hydrophilic metal oxide powder comprising a metal oxide and a surface modification of the metal oxide, wherein a) the metal oxide is selected from the group consisting of TiO2, ZrO2, SiO2, Al2O3, Fe2O3, Fe3O4, Sb2O3, WO3, CeO2 and mixed oxides thereof and b) the surface modification b1) comprises silicon atoms and aluminum atoms and b2) the silicon atoms are at least partly bonded to a hydrocarbon radical via a C atom and b3) the Al/Si molar ratio of the surface modification is 1:2-1:20.

Abstract: A dispersion, comprising 0.1 to 25% by weight hydrophobized silica, 8 to 90 wt % of at least one alcohol selected from the group consisting of ethanol, 1-propanol and 2-propanol, 7 to 89 wt % of water, 0 to 30% by weight solvent immiscible with water, and 0.04 to 5 wt % of at least one carboxyvinyl polymer present in neutralized form, can be applied to a surface using a non-drip application method and, by modifying the surface with hydrophobized silica, imparts water-repelling and self-cleaning properties to the surface.

Abstract: Stable, pourable silicon dioxide dispersion, in which the average, number-related aggregate diameter of the silicon dioxide particles in dispersion is less than 200 nm, and which comprises at least 35 wt. % of a silicon dioxide powder, 3 to 35 wt. % of at least one polyol, 20 to 60 wt. % of water, 0 to 10 wt. % of an additive and a substance having an alkaline action in an amount such that a pH of 10<pH<12 is established. It can be prepared by a procedure in which silicon dioxide powder is introduced into water and a polyol in a rotor/stator machine, the pH being less than 5, and the mixture is dispersed until the current uptake of the rotor/stator machine is largely constant, and a substance having an alkaline action is subsequently added in an amount such that a pH of the dispersion of 10<pH<12 results, the substance having an alkaline reaction being added so rapidly that no gel formation takes place.

Abstract: Aqueous dispersion comprising hydrophobized silicon dioxide particles, comprising a. 50%-80% by weight of water, b. 10%-30% by weight of hydrophobized silicon dioxide particles, c. 5%-15% by weight of at least one alcohol alkoxylate of the general formula R1O((CH2)mO)nH, where R1 is a branched or unbranched alkyl or alkenyl radical having 10-25 C atoms, m is 2 or 3 and n is 10-50, d. 0.5%-5% by weight of at least one amine and/or amino alcohol having a molecular weight of less than 500 and e. 0%-1% by weight of N-methylpyrrolidone, all figures for weight percentages being based on the dispersion. Paint formulation comprising the dispersion.

Abstract: Slurry which contains a) from (50) to (80)% by weight of refractory particles having an average particle size of from (0.5) m to (150) m, b) from (5) to (35)% by weight of aluminum oxide particles having an average particle diameter of less than (300) nm and c) from (5) to (35)% by weight of water and d) a pH of from (5) to (12). Process for producing the slurry using a dispersion, and also the dispersion itself. Process for producing a casting mold, and also the casting mold itself.

Abstract: A method of fractionating a dispersion of oxidic nanoparticles wherein at least one step of the method is a membrane crossflow filtration step, the flow of the dispersion over the membrane being brought about by means of driven rotating parts; and dispersions of oxidic nanoparticles that are obtainable by the method.

Abstract: Aqueous dispersion comprising hydrophobized silicon dioxide particles, comprising a. 50%-80% by weight of water, b. 10%-30% by weight of hydrophobized silicon dioxide particles, c. 5%-15% by weight of at least one alcohol alkoxylate of the general formula R1O((CH2)mO)nH, where R1 is a branched or unbranched alkyl or alkenyl radical having 10-25 C atoms, m is 2 or 3 and n is 10-50, d. 0.5%-5% by weight of at least one amine and/or amino alcohol having a molecular weight of less than 500 and e. 0%-1% by weight of N-methylpyrrolidone, all figures for weight percentages being based on the dispersion. Paint formulation comprising the dispersion.

Abstract: Aluminum oxide dispersion, which is stable in a pH range 5 from 5 to 9 and has an aluminum oxide content of at least 40 wt. %, obtainable by dispersing pyrogenically produced aluminum oxide particles in an aqueous phase, wherein one or several at least dibasic hydroxycarboxylic acids present dissolved in the dispersion and at least one salt of a 10 dialkali metal hydrogen phosphate and/or alkali metal dihydrogen phosphate are added to the aqueous phase each mutually independently in a quantity of 0.3?3×10?6 mol/m2 of aluminum oxide specific surface area.

Abstract: Process for the production of an aqueous dispersion of pyrogenically produced metal oxide and metalloid oxide powders with a BET surface area of between 5 and 600 m2/g, with a metal oxide or metalloid oxide content in the dispersion of between 5 and 25 wt. %, comprising the following steps: water, which is optionally adjusted to pH values of between 2 and 4 by adding acids, is circulated from a receiving vessel via a rotor/stator machine, and metal oxide or metalloid oxide powder is introduced, using a feed device, into the shear zone between the slots in the rotor teeth and the stator slots, continuously or discontinuously and with the rotor/stator machine running, in a quantity such that a predispersion with a solids content of between 20 and 40 wt.

Abstract: Dispersion containing, in addition to water, 0.5 to 20 wt. % of hydrophobic silica, 0.01 to 10 wt. % of a gelling or viscosity-increasing additive, 0.1 to 1 wt. % of a preservative and 0 to 1 wt. % of a surface-active substance. It is prepared by a procedure in which the individual components are dispersed successively or together into the water and in this procedure the individual components are deaerated before and/or during the addition or the dispersion is deaerated during the individual dispersing steps. The dispersion can be employed as an insecticide.

Abstract: Provided is a process for preparing surface-modified silicon dioxide particles with a mean particle diameter of at most 100 nm, involving (A) high-pressure grinding of a predispersion having (i) surface-modified silicon dioxide particles which are at least partly aggregated, are bonded to the surface-modifying component via Si—O—Si bonds, and still have reactive groups on their surface; (ii) an organosilicon compound which has a silicon-carbon bond and a functional group which can react with the reactive groups to form a covalent Si—O—Si bond; and (iii) a solvent, to form a dispersion; and (B) removing the liquid phase of the dispersion. Also provided are redispersible, surface-modified silicon dioxide particles obtained by this process, and their use in toner powders, silicone rubber, adhesives, and scratch-resistance surface coatings.

Abstract: Aqueous dispersion which comprises hydrophobized silicon dioxide particles and in each case one or more dispersing additives, a basic composition, and which is free of color pigments, inactive fillers and binders, in which the hydrophobized silicon dioxide particles have a methanol wettability of 30 to 60 and are present in the dispersion with a proportion of 0.

Abstract: Reactor for carrying out chemical and physical materials transformations, which comprises a reaction space enclosed by a reactor housing, where the reactor housing has at least two lateral fluid inlets having adjustably mounted nozzles which include an angle of about 20-160 degrees and through which fluid jets which impinge on one another at a common collision point within the reaction space are passed and the reactor has a fluid outlet at the bottom of the reaction space, which is characterized in that—an exchangeable bottom plate•which has a hole as fluid outlet and•on which moveably supported spheres are located so as to block the original path of the individual fluid jets in the unaligned state rests on the bottom of the reaction space and—a half shell standing upright on the bottom of the reaction space is located between each moveably supported sphere and the wall of the reactor space and—bottom plate, half shell and moveably supported spheres comprise one or more hard materials.

Abstract: Preparation for producing refractory materials, characterized in that it comprises one or more particulate, refractory components and one or more binders, where—the particulate, refractory component has a mean particle diameter of >0.3 m and—the binder is selected from among—from 0.05 to 50% by weight of a very finely particulate binder having a mean particle diameter of from 10 nm to 0.3 m selected from the group consisting of aluminum oxide, titanium dioxide, zirconium dioxide and/or mixed oxides of the abovementioned oxides, —from 0 to 20% by weight of an inorganic binder, from 0 to 20% by weight of a hydraulically setting binder, —from 0 to 15% by weight of an organic, silicon-free binder—and the preparation additionally contains from 0 to 35% by weight of water, where—the proportion of the particulate, refractory component is equal to 100 and the percentages of the further materials in the preparation are based on the particulate component.