Abstract: The present invention relates to a process for preparing TiO2/SiO2 mixed oxides or the hydrates and/or oxide hydrates thereof comprised of 0.5 to 95 wt % SiO2 and the balance as TiO2, each referring to the completely calcined product, by using titanium alcoholates and aqueous silica sol. Moreover, the invention relates to the use of these mixed oxides as catalyst carriers.

Abstract: The chemical composition and method of the invention enable characterization of microscopic defects in membranes such as pinholes, cracks or fissures. The present invention, however, can be used to characterize defects on different types of porous and non-porous membranes used for diverse applications in various industries. It uses brightly fluorescing silica or silsesquioxane spheres prepared with pre-determined definitive and uniform sizes (15 nm-50 microns). The spheres' uniform, controlled size allows them to be used to characterize defects or holes in membranes based on a size exclusion mechanism. The spheres used are engineered to glow brightly when exposed to ultraviolet light in order to allow visual or highly sensitive fluorescence spectroscopy or microscopy to characterize the passage of the particles through defects or holes in a membrane and even identify where the defect is located.

Abstract: Cross-linked sol-gel like materials and cross-linked aerogels, as well as methods for making such cross-linked sol-gel like materials and cross-linked aerogels are described.

Abstract: The invention relates to a process for the preparation of a titanium catalyst which process comprises: (a) drying a silica carrier at a temperature of from 300 to 800° C. to obtain a dried carrier; (b) contacting the dried carrier obtained in step (a) with a gas stream containing titanium halide at a temperature in the range from 125° C. lower to 125° C. higher than the drying temperature of step (a) and at a pressure higher than 0.8 bar to obtain an impregnated carrier; (c) calcining the impregnated carrier obtained in step (b) to obtain the titanium catalyst.

Abstract: Disclosed is a method of manufacturing superhydrophobic silica-based powder, including adding a water glass solution, which is not subjected to ion exchange, serving as a precursor, with an organosilane compound having an alkaline pH and an inorganic acid to thus subject the water glass solution to surface modification and gelation, thereby producing hydrogel, immersing the hydrogel in a nonpolar solvent to thus subject the hydrogel to solvent exchange and Na+ removal, and drying the hydrogel, subjected to solvent exchange, at ambient pressure, thereby manufacturing aerogel powder. This invention is very important from an industrial point of view because it involves a very simple process and realizes economic benefits.

Abstract: A modified synthetic silica powder is produced by heating in vacuum an amorphous synthetic silica powder produced by a sol-gel process, and then cooling the heated silica powder in an atmosphere containing helium. When the modified synthetic silica powder is fused and vitrified in a process of crucible production, the resulting quartz glass crucible contains hardly any bubbles.

Abstract: Structurally stable and mechanically strong ceramic oxide aerogels are provided. The aerogels are cross-linked via organic polymer chains that are attached to and extend from surface-bound functional groups provided or present over the internal surfaces of a mesoporous ceramic oxide particle network via appropriate chemical reactions. The functional groups can be hydroxyl groups, which are native to ceramic oxides, or they can be non-hydroxyl functional groups that can be decorated over the internal surfaces of the ceramic oxide network. Methods of preparing such mechanically strong ceramic oxide aerogels also are provided.

Abstract: A method for preparing a silica aerogel in the form of permanently hydrophobic powder in a short time, wherein the silica aerogel has a high specific surface area and high functionality, and is prepared by subjecting a wet gel to a solvent exchange process and a silylizing process in a mixture solvent including a silylizing agent at the same time, the wet gel being prepared using a water glass as a raw material and adding a surfactant at a room temperature.

Abstract: The present invention generally relates to polysilicate microgels. More specifically, the invention relates to a process for preparing aqueous polysilicate microgels which comprises mixing an aqueous solution of alkali metal silicate with an aqueous phase of silica-based material having a pH of 11 or less, to polysilicate microgels per se and to the use thereof as flocculating agents in paper making and water purification. The invention further relates to a process for the production of paper from a suspension of cellulosic fibers, and optional filler, which comprises adding to the suspension at least one cationic or amphoteric organic polymer and a polysilicate microgel, forming and draining the suspension on a wire.

Abstract: A transparent porous SiO2 coating for a transparent substrate material, for example polycarbonate, has advantageous antireflective properties. The coating is produced by a sol-gel process, at least one component which causes porosity being present during at least part of the sol-gel process and being removed and/or destroyed after the sol-gel process has ended. The at least one component which causes porosity is a polymer, the average molar mass of the polymer being preferably =5000 Da to =50 000 Da, more preferably =10 000 Da to =20 000 Da.

Abstract: Pelletized silica particles characterized by a round shape and a monomodal particle size distribution are produced by dispersing silica particles into water, adding water to the dispersion, mixing with alkoxisilane, pouring the mixture into an organic solvent, filtering and washing the silica particles obtained. The pelletized silica particles can be used to produce glass monoliths.

Abstract: Nanoporous sol-gel derived monoliths and methods for making nanoporous sol-gel derived monoliths are provided. The methods enable fine control over pore size and pore size distribution, e.g., so that pore sizes can be predetermined and precisely tuned over a range from 0.3 nm to about 30 nm, or over a range from about 0.3 nm to about 10 nm. The monoliths may be derived from any suitable sol-gel, but in some instances they are derived from silica sol-gels. The sol-gel derived monoliths with finely tunable pore sizes and narrow pore size distributions may be used for a variety of applications, e.g., as substrates or templates for high surface area electrodes, as substrates for high surface area sensor, or as a component in a filtration apparatus.

Abstract: Filtration materials comprising heat-treated metal-doped precipitated silica or silica gel materials with sulfur-containing functional silane surface treatments are provided. Such materials exhibit excellent mercury removal properties from flue gas emissions through the trapping of mercury vapors within a smokestack (or other like site). The metal dopant and the sulfur-containing functional silane components applied to the surface of the target metal-doped gels effectuate the desired mercury reactions to permit capture thereof. In combination, such components permit versatile utilization in either a fixed bed configuration or through a dynamic mercury removal procedure. Methods of using and specific filter apparatuses are also encompassed within this invention.

Abstract: An ambient pressure, low cycle time method for the synthesis and manufacture of a low cost, highly insulting, highly translucent, and low density transition metal-based hydrophilic and hydrophobic nanogel. The important aspects are the method of synthesis, the stage of imparting hydrophobicity, and the process of manufacture. The method comprises the steps of mixing a chilled precursor solution with a chilled catalyst solution such that the mixture has a pH of between 9.5 and 12.2. The mixture is maintained at a temperature of 34° F.-55° F. for between 1 and 120 minutes to form a gel. The gel is silated the gel for about 120 minutes, washed in a wash fluid, then dried and annealed to form the aerogel.

Abstract: Novel, monodispersed, spherical ZrO2 particles in the size range of approximately 10 to approximately 600 nm exhibiting metastable tetragonal crystal structure at room temperature and novel methods of preparation. The ZrO2 particles are approximately 100% in the tetragonal phase at room temperature and can be pure and free of foreign oxides. The novel method can include mixing zirconium-alkoxide and an alcohol, forming preparation one, followed by separately dissolving completely de-ionized water and a polymeric steric stabilizer in an alcohol forming preparation two. Next the preparations can be mixed with vigorous stirring while subjecting the materials to hydrolysis and condensation reactions with very slow stirring. Next, there is waiting for the formation of a sol from the mixture, followed by drying at approximately 80 degrees C. to form resultant material followed by crushing the resultant material.

Abstract: An environmental control for use in air handling systems that are required to provide highly effective filtration of noxious gases is provided. In one embodiment, a filtration system utilizes a novel combination of at least one metal-doped silica-based gel and zeolite materials to trap and/or modify, and remove such undesirable gases (such as ammonia, ethylene oxide, formaldehyde, and nitrous oxide, as examples) from an enclosed environment. The gel component exhibits specific porosity requirements and density measurements; the zeolite component is generally acidic and is preferably not reacted with any salts or like substances. The novel combination of such gels and zeolites permits highly effective noxious gas filtration over a wide range of known toxic industrial chemicals such that excellent breakthrough results are attained, particularly in comparison with prior media filtration products.

Abstract: The present invention relates to an apparatus and a method for manufacturing amorphous nanoporous silica enabling mixing of source materials with accurate equivalence ratio by generating an eddy current using high-speed reaction nozzles and capable of controlling physical properties using a continuous circulation polymerizer which performs high-speed stirring and low-speed stirring and amorphous nanoporous silica prepared by the method, which has a BET surface area of 100-850 m2/g, a pore size of 2-100 nm and a pore volume of 0.2-2.5 mL/g.

Abstract: New silica gel materials and novel methods of producing such are provided. The method itself entails a manner of mixing the reactants together in a one-pot process such that the time required for aging is reduced without compromising the ability to target pore size production. In such a way, the pH of the reaction drives pore size development, thereby permitting a more efficient process to be followed in terms of expensive drying/heating steps being reduced timewise, if not altogether. Furthermore, in one embodiment, the resultant gel materials exhibit a certain pore size minimum while simultaneously exhibiting a degree of softness heretofore unavailable. As such, not only is this novel method more efficient in silica gel manufacture, but the resultant materials are completely novel as well. The gel materials made therefrom may be utilized in a variety of different end uses, such as cooking oil filtration, soft skin cleansers, dental abrasives, and the like.

Abstract: A process for producing inorganic spheres, which comprises injecting an aqueous liquid containing an inorganic compound into a laminar flow of an organic liquid which runs at a flow rate of from 0.001 to 2 m/s in a flow path compartmentalized by a partition wall through a plurality of inlet holes formed in one partition wall to form a W/O type emulsion containing the organic liquid as a dispersion medium and the aqueous liquid containing the inorganic compound as a dispersed phase, and solidifying the aqueous liquid containing an inorganic compound in the W/O type emulsion, wherein the partition wall having a plurality of inlet holes is made of a metal sheet having a surface subjected to water repellent treatment.

Abstract: Process for the production of monoliths by means of the sol-gel process, comprising the following steps: a. hydrolysis of an alkoxide in aqueous solution to form a hydrolysate and optionally evaporation to optimum concentration of the same, b. addition of an oxide prepared by the pyrogenic route, c. mixing of the hydrolysate of the alkoxide with the oxide prepared by the pyrogenic route to form a colloidal sol, d. optional removal of coarse contents from the colloidal sol, e. gelling of the colloidal sol in a mould, f. optional replacement of the water contained in the resulting aerogel by an organic solvent, g. drying of the aerogel, h. heat treatment of the dried aerogel, the coarse content being removed from the colloidal sol.

Abstract: The invention concerns a method for preparing low water uptake precipitated silicas, comprising successive steps which consist in: (a) producing an initial starter including a silicate, the silicate concentration in said starter, expressed in SiO2 equivalent, being less than 15 g/L; (b) bringing the medium pH to a value ranging between 7 and 8 by adding an acidifying agent, (c) in the resulting medium, simultaneously adding a silicate and an acidifying agent the respective amounts of silicate and acidifying agent added in time being specifically such that, during the entire addition (1) the reaction medium pH stays between 7 and 8, and (ii) the silicon concentration in the medium, expressed in SiO2 equivalent, stays below 35 g/L; (d) adding an acidifying agent in the medium resulting from step (c), so as to bring the medium to a pH ranging between 3 and 6.5; and (e) filtering the resulting aqueous silica dispersion, then drying the filter cake obtained at the end of the filtering step.

Abstract: An environmental control for use in air handling systems that are required to provide highly effective filtration of noxious gases is provided. In one embodiment, a filtration system utilizes a novel combination of at least one metal-doped silica-based gel and zeolite materials to trap and/or modify, and remove such undesirable gases (such as ammonia, ethylene oxide, formaldehyde, and nitrous oxide, as examples) from an enclosed environment. The gel component exhibits specific porosity requirements and density measurements; the zeolite component is generally acidic and is preferably not reacted with any salts or like substances. The novel combination of such gels and zeolites permits highly effective noxious gas filtration over a wide range of known toxic industrial chemicals such that excellent breakthrough results are attained, particularly in comparison with prior media filtration products.

Abstract: This invention relates to a process for converting silica to polysilicate gels or hydrogels by combining an aqueous silica source with a CO2 feed stream as the gel initiator, whereby the reaction stream is propelled at high velocity and turbulence maintaining the CO2 uptake rate in the reaction stream. The invention also relates to a process for converting silica to polysilicate by pre-carbonating water at pressures of equal to or greater than 100 psig before initiating the polysilicate reaction.

Abstract: A method for producing synthetic magadiite, including the step of: heating a liquid aqueous colloidal silica suspension, the liquid aqueous colloidal silica suspension having a mole ratio of sodium hydroxide to silica and a mole ratio of water to silica effective to produce a synthetic magadiite wherein more than fifty percent by weight of the synthetic magadiite is platy synthetic magadiite. The synthetic platy magadiite can be converted to the acid form and: (a) heated to produce quartz-like plates; or Coalkylated to produce an organophilic material. In another aspect the instant invention is a method for the production of platy sodium octasilicate which includes the step of: heating a liquid aqueous colloidal silica dispersion containing silica, sodium oxide, and water, the mole ratio of the silica to the sodium oxide being in the range of from about 3.5 to about 10.

Abstract: New silica gel materials and novel methods of producing such are provided. The method itself entails a manner of mixing the reactants together in a one-pot process such that the time required for aging is reduced without compromising the ability to target pore size production. In such a way, the pH of the reaction drives pore size development, thereby permitting a more efficient process to be followed in terms of expensive drying/heating steps being reduced timewise, if not altogether. Furthermore, in one embodiment, the resultant gel materials exhibit a certain pore size minimum while simultaneously exhibiting a degree of softness heretofore unavailable. As such, not only is this novel method more efficient in silica gel manufacture, but the resultant materials are completely novel as well. The gel materials made therefrom may be utilized in a variety of different end uses, such as cooking oil filtration, soft skin cleansers, dental abrasives, and the like.

Abstract: New silica gel materials and novel methods of producing such are provided. The method itself entails a manner of mixing the reactants together in a one-pot process such that the time required for aging is reduced without compromising the ability to target pore size production. In such a way, the pH of the reaction drives pore size development, thereby permitting a more efficient process to be followed in terms of expensive drying/heating steps being reduced timewise, if not altogether. Furthermore, in one embodiment, the resultant gel materials exhibit a certain pore size minimum while simultaneously exhibiting a degree of softness heretofore unavailable. As such, not only is this novel method more efficient in silica gel manufacture, but the resultant materials are completely novel as well. The gel materials made therefrom may be utilized in a variety of different end uses, such as cooking oil filtration, soft skin cleansers, dental abrasives, and the like.

Abstract: The present invention relates to novel, organically modified aerogels, uses thereof, and a process for producing them in which a) a hydrogel is introduced as an initial charge, b) the hydrogel obtained in step a) is subjected to surface modification, and c) the surface-modified gel obtained in step b) is dried. The present invention additionally relates to novel, organically modified wet gels, to a process for producing them, and to their use.

Abstract: Aerogel particles having a mean particle size less than 1 micron, products containing the same, processes of making the same, and uses thereof are described. A process of making the particle is also described wherein starting aerogel particles are homogenized or wet milled. The starting aerogel particles can be surface treated during the milling process to prevent agglomeration or aggregation. The aerogel particles can be used in a variety of products and applications.

Abstract: To provide a process for producing inorganic spheres having a substantially uniform particle size with high productivity. In a process for producing inorganic spheres, which comprises a step of injecting an alkaline aqueous liquid containing an inorganic compound into a laminar flow of an organic liquid containing a surfactant through micropores to form a W/O type emulsion, and a step of solidifying droplets of the aqueous liquid containing an inorganic compound in the W/O type emulsion by an acid to form inorganic spheres, as the organic liquid, one which is brought into contact with an acid in a state of the W/O type emulsion or after separated from the W/O type emulsion, or one which is brought into contact with the aqueous liquid and then separated and recovered, is used.

Abstract: A kinetically controlled vapor reaction process for synthesizing silica areogel in a reaction container by injection of a precursor reagent vapor, a catalyst reagent vapor, super saturated steam as a component of the catalyst solution, and a hydrophobic reagent vapor amd continuously mixing vapor droplets of the precursor, catalyst and water reagents in a super saturated state to continuously nucleate in a hydrolysis/poly-condensation reaction and deposit as silica aerogel.

Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.

Abstract: A surface-modified, aerogel-type, structured silica is produced by spraying an aerogel-type, structured silica with a silanizing agent, post-mixing and conditioning. It can be used as a flatting agent.

Abstract: The present invention relates generally to an environmental control unit for use in air handling systems that provides highly effective filtration of noxious gases (such as ammonia). Such a filtration system utilizes novel metal-doped silica-based gels to trap and remove such undesirable gases from an enclosed environment. Such gels exhibit specific porosity requirements and density measurements. Furthermore, in order for proper metal doping to take effect, such gels must be treated while in a wet state. The combination of these particular properties and metal dopant permits highly effective noxious gas filtration such that uptake and breakthrough results are attained, particularly in comparison with prior silica gel filtration products. Methods of using and specific filter apparatuses are also encompassed within this invention.

Abstract: Disclosed herein is a rapid preparation process of aerogel. More specifically, the present invention relates to a rapid preparation process of aerogel which enables a considerable reduction in preparation time and preparation costs via simultaneous treatment of solvent exchange and surface-modification of hydrophilic-to-hydrophobic transition. The rapid preparation process comprises mixing a cation exchange resin with sodium silicate (water glass) as a starting material, and removing the sodium ion from the sodium silicate, to subject the sodium silicate to ion exchange; adding a base catalyst and an organosilane compound to the sodium silicate to subject the sodium silicate to gelation; aging the gellized silica gel at room temperature for 2 to 4 hours to discharge water from the silica gel and to modify the surface of the silica gel into hydrophobicity; and drying the hydrophobic silica gel at atmospheric pressure for 18 to 27 hours.

Abstract: A mesoporous material is described. It includes a network of interconnected pores within an L3 phase structure. The pores include pore walls of a silicate material functionalized with at least one metal cation—usually a transition metal. Articles which include the mesoporous material are also disclosed, along with methods for making the mesoporous material.

Abstract: Unique abrasive and/or thickening materials that are in situ generated compositions of precipitated silicas and silica gels are provided. Such compositions exhibit different beneficial characteristics depending on the structure of the composite in situ generated material. With low structured composites (as measured via linseed oil absorption levels from 40 to 100 ml oil absorbed/100 g composite), simultaneously high pellicle film cleaning properties and moderate dentin abrasion levels are possible in order to accord the user a dentifrice that effectively cleans tooth surfaces without detrimentally abrading such surfaces. Increased amounts of high structure composite materials tend to accord greater viscosity build and thickening benefits together with such desirable abrasion and cleaning properties, albeit to a lesser extent than for the low structure types.

Abstract: Unique abrasive and/or thickening materials that are in situ generated compositions of precipitated silicas and silica gels are provided. Such compositions exhibit different beneficial characteristics depending on the structure of the composite in situ generated material. With low structured composites (as measured via linseed oil absorption levels from 40 to 100 ml oil absorbed/100 g composite), simultaneously high pellicle film cleaning properties and moderate dentin abrasion levels are possible in order to accord the user a dentifrice that effectively cleans tooth surfaces without detrimentally abrading such surfaces. Increased amounts of high structure composite materials tend to accord greater viscosity build and thickening benefits together with such desirable abrasion and cleaning properties, albeit to a lesser extent than for the low structure types.

Abstract: A method of producing substantially spherical lyogels in water insoluble silylating agents is provided. The present invention refers to a method of producing substantially spherical lyogels in which a) a lyosol is provided, b) the lyosol obtained in step a) is transferred to at least one silylating agent in which the lyosol is insoluble, and c) the spherical lyosol formed in step b) is gelatinised in at least one silylating agent in which the lyosol is likewise insoluble, to produce the lyogel.

Abstract: New aerogels are disclosed which comprise silica and at least one organic polymer having polar functional groups. Also disclosed are methods for making such aerogels and for making them as substantially transparent objects. In addition, gas detectors, liquid and gas absorbing objects, and optical devices made using these aerogels are disclosed. The present invention concerns optical elements which are substantially transparent and exhibit low refractive indices. The invention further relates to detectors of reactive and absorbate gases based on the physical changes exhibited by the aerogels upon reacting with or absorbing such gases. The present invention further concerns printable objects comprising these aerogels, specifically when the print media are imaged by the absorption of liquid and the spatial localization of pigments or dyes. The invention further concerns reactive gas absorbers comprising these aerogels and the catalytic function the aerogels serve to catalyze subsequent chemical reaction.

Abstract: The invention relates to hydrophobicized precipitated silicas that possess an extremely high whiteness and extremely low moisture absorption. The hydrophobic precipitated silicas are prepared, inter alia, by coating with silicone oil and oxidative heat treatment.

Abstract: A high concentration silica slurry can be used for polishing of substrates, such as semiconductor materials. The slurry contains a silica powder dispersed in an solvent. The silica slurry has a silica concentration of more than 50% by weight and a viscosity of less than 1000 mPa·s, wherein the silica powder has a ratio DL/DT of less than 1.3, wherein DL is an average particle size of the silica powder measured by a laser diffraction particle size distribution method and DT is an average primary particle size of the silica powder measured by a TEM photography observation, and wherein the silica powder has an average primary particle size of from 0.08 ?m to 0.8 ?m.

Abstract: Spiral shaped fibers were utilized to prepare completely novel metal oxide nanotubes comprising solely metal oxides. The metal oxide nanotubes comprise solely a hollow cylinder shaped metal oxide which may contain hydroxyl groups constituting a double helix and having hole diameter distributions containing two peak hole diameters ranging from 1 to 2 nm and from 3 to 7 nm. The tubes may be obtained by forming spiral shaped fibers from a solution of compound 1 and compound 2 and using the fibers as a template for making the nanotubes. The hydrogen adsorption and storage capacity of the metal oxide nanotubes are extremely good.

Abstract: A method of preparing a solution for forming a doped gel monolith includes providing a first substance including a metal alkoxide. The method further includes providing a second substance including a catalyst. The method further includes providing a chemical including a dopant. The method further includes forming a solution including the dopant, said forming including mixing the first substance and the second substance together. The method further includes cooling the solution to a mixture temperature which is at or below zero degrees Celsius, wherein the solution has a significantly longer gelation time at the mixture temperature than at room temperature.

Abstract: New methods of producing narrower particle size distribution precipitated silica and/or silicate materials are provided. Such a method permits a significant reduction in manufacturing costs through the utilization of more efficient drying/evaporation components, in essence, in one potentially preferred embodiment, production of such silica and/or silicate materials followed directly by a hydraulic chamber press filtering step combined with vacuum dewatering subsequently leading to the needed resultant particle comminution. The resultant precipitated silicas and/or silicates produced thereby exhibit greater density prior to comminution and thus greater propensity for more uniform milling than previously utilized and prevalent spray/flash drying apparatuses.

Abstract: Silica with a large pore volume, a large specific surface area, a narrow pore distribution, low contents of unwanted metal impurities, and excellent physical properties such as high heat-resistance and water-resistance is provided. The silica has a mode pore diameter (Dmax) of 20 nm or less, and a solid-state Si nuclear magnetic resonance (hereinafter called solid-state Si NMR) spectrum of the silica includes a chemical shift (? ppm) of Q4 peak meeting the following inequality (I). ?0.0705×(Dmax)?110.36>???(I) The silica with such properties can be suitably used in fields of which particularly excellent heat resistance and water resistance are required, and moreover controlled pore properties, and the fact that physical properties scarcely change over a long period of time are required among the above-mentioned applications.

Abstract: A hydrophobic precipitated silica is prepared by a process comprising: a) preparing a mixture of an organopolysiloxane derivative and a precipitated silica; b) conditioning the mixture obtained at a temperature ranging from 10 to 150° C. for a period ranging from 0.5 to 72 h, and c) conducting oxidative heat treatment under fluid conditions at a temperature more than 300° C. with an oxidizing gas.

Abstract: A method of producing a silica gel by hydrolyzing a silicon alkoxide and subjecting the resulting hydrogel to a hydrothermal treatment substantially without aging it is described. Also described in a silica gel produced by such a method and a silica gel which has the following characteristics: (a) the pore volume is from 0.6 to 1.6 ml/g, (b) the specific surface area is from 300 to 900 m2/g, (c) the mode diameter (Dmax) of pores is less than 20 nm, (d) the volume of pores having diameters within ±20% of Dmax is at least 50% of the total pore volume, (e) it is amorphous, and (f) the content of metal impurities is at most 500 ppm.

Abstract: Non-porous spherical silica having a mean particle diameter of 0.1–20 ?m and satisfying the following conditions: (a) a maximum particle diameter is 4 times the mean particle diameter or less; (b) ?1/?2<1.0, wherein ?1 and ?2 are the viscosity of a 70:30 (by weight) mixture of the non-porous spherical silica and a Bisphenol A type liquid epoxy resin, as measured at a rotation number of 0.5 rpm and 2.5 rpm, respectively, in a viscometer.

Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.

Abstract: The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises: a) preparation of a finely divided silica xerogel, b) loading of the xerogel with chromium from a solution of chromium trioxide or a chromium compound which is converted into chromium trioxide under the conditions of step c), and c) activation of the resulting product at from 400 to 1100° C. in a water-free gas stream comprising oxygen in a concentration of above 10% by volume, wherein a fluoride doping with a fluorinating agent is carried out in step b) or in step c). Furthermore, the invention relates to a catalyst for the polymerization of olefins which is obtainable by the process of the invention and to a process for the polymerization of olefins in which an olefin or an olefin mixture is polymerized in the presence of a catalyst according to the invention.