Abstract: There is provided a first substrate having a first main surface, a second substrate having a second main surface, a bonding member bonding the first main surface and the second main surface, and a flow path positioned between the first substrate and the second substrate and extended in a parallel direction with the first main surface and the second main surface, and the bonding member has a projection which is protruded from a portion between the first main surface and the second main surface toward an inner part of the flow path, the flow path includes a first portion having the projection provided in an inner part and a second portion linked to the first portion adjacently to an opposite side to a side where the projection of the first portion is provided, and a height of the first substrate is greater than a height of the second portion in the thickness direction.

Abstract: Embodiments described herein relate to methods and systems for dewatering solutions via forward osmosis.

Abstract: An object of the present invention is to provide a method for producing metal oxide particles, in which metal oxide particles with high photocatalytic activity is produced, and a production apparatus therefor. The above object can be achieved by using a method for producing metal oxide particles, which includes subjecting a reaction gas containing metal chloride and an oxidizing gas containing no metal chloride in a reaction tube (11) to preheating, and then subjecting a combined gas composed of the reaction gas and the oxidizing gas to main heating in a main heating region (A) apart from the downstream side of the junction (5b), wherein the time until the combined gas from the junction (5b) arrives at the upstream end (A1) of the main heating region (A) is adjusted to be less than 25 milliseconds.

Abstract: An apparatus and method for performing permeation testing on materials used in personal protective equipment is described. Two or more test cells are loaded with swatches of material and inserted into the testing apparatus. Chemicals to be tested on the material are loaded into one or more syringes and may be introduced into the top of the test cells as a liquid or a vapor. Vapor is collected from the bottom of the test cells, underneath the swatches of material, and tested for concentration of the chemicals being tested. The apparatus and method facilitates instantaneous breakthrough analysis, control of the sample environment and ease of operator use and calibration.

Abstract: There is provided a method and an apparatus for producing metal oxide particles, which produce metal oxide particles having a high photocatalytic activity with high yield.

Abstract: A device for producing titanium metal comprises (a) a first heating unit that heats and gasifies magnesium and a first channel that feeds the gaseous magnesium, (b) a second heating unit that heats and gasifies titanium tetrachloride so as to have a temperature of at least 1600° C. and a second channel that feeds the gaseous titanium tetrachloride, (c) a venturi section at which the second channel communicates with an entrance channel, the first channel merges into a throat and as a result the magnesium and the titanium tetrachloride combine in the throat and a mixed gas is formed in the exit channel, and in which the temperature of the throat and the exit channel is regulated to be at least 1600° C., (d) a titanium metal deposition unit that communicates with the exit channel and has a substrate for deposition with a temperature in the range of 715-1500° C., and (e) a mixed gas discharge channel that communicates with the titanium metal deposition unit.

Abstract: Methods for preparing and using a photocatalyst are described. The catalyst is prepared by oxidation of a metal salt which has been doped in situ to form a photocatalyst active in visible light. The photocatalyst is used for degrading toxic and irritating compounds and infectious agents.

Abstract: This disclosure relates to a process for producing titanium dioxide, comprising: a) reacting a alloy comprising silicon and aluminum having a melting point of about 482° C. to about 660° C., with chlorine gas at temperatures above 190° C. to form chlorides of silicon and aluminum; b) adding titanium tetrachloride to the chlorides of silicon and aluminum of step (a); c) oxidizing the chlorides of silicon and aluminum and titanium tetrachloride of step (b); and d) forming titanium dioxide.

Abstract: This disclosure relates to a process for producing titanium dioxide, comprising: reacting aluminum and an alloy comprising silicon and titanium having a silicon content of at least 5%, based on the weight of the ahoy, with chlorine gas at temperatures above 190° C. to form chlorides of silicon, aluminum and titanium; adding titanium tetrachloride to the chlorides of silicon, aluminum and titanium; oxidizing the chlorides of silicon, aluminum and titanium and titanium tetrachloride; and forming titanium dioxide.

Abstract: A process for producing titanium dioxide, comprising: a) reacting an alloy comprising a metal selected from the group consisting of aluminum, titanium and mixtures thereof, wherein one metal is a major component of the alloy, and an element, with chlorine gas to form chlorides of aluminum, titanium or mixtures thereof and chlorides of the element, at or above the boiling point of the chloride of the major component of the alloy; with the proviso that the element does not comprise Ti when the metal is Ti and does not comprise Al when the metal is Al; (b) adding titanium tetrachloride to the chlorides formed in step (a); (c) oxidizing the chlorides formed in step (a), and titanium tetrachloride of step (b); and (d) forming titanium dioxide.

Abstract: Provided is a method for producing decahedral titanium oxide particles, wherein the decahedral titanium oxide particles are produced by allowing a reaction gas containing titanium tetrachloride to flow into a reaction pipe having a partial double-pipe structure in which a hollow internal cylinder is inserted into an upstream portion of a hollow external cylinder, the method comprising: performing a preheating on the reaction gas containing titanium tetrachloride and a barrier gas not containing metal chlorides in a region on the upstream side of a downstream end of the hollow internal cylinder, while allowing the reaction gas to flow into the hollow internal cylinder and the barrier gas to flow between the hollow internal cylinder and the hollow external cylinder; and performing a main heating on the reaction gas in a downstream region apart from the downstream end of the hollow internal cylinder to thermally decompose the titanium tetrachloride.

Abstract: The manufacture of titanium dioxide by oxidation of titanium tetrachloride in a plug flow reactor, wherein the titanium tetrachloride is introduced into the reactor in at least two stages and is used exclusively in liquid form. The total quantity of liquid TiCl4 used is split up in several stages. A small quantity is added in the first stage in order to start combustion despite using the liquid phase. In the first phase, the activation energy required is provided solely via the preheated oxygen. In all other stages, the activation energy is provided by the preheated oxygen and the reaction enthalpy of TiCl4 oxidation released in the upstream stages.

Abstract: The manufacture of titanium dioxide by oxidation of titanium tetrachloride in a plug flow reactor, wherein the titanium tetrachloride is introduced into the reactor in at least two stages and is used exclusively in liquid form. The total quantity of liquid TiCl4 used is split up in several stages. A small quantity is added in the first stage in order to start combustion despite using the liquid phase. In the first phase, the activation energy required is provided solely via the preheated oxygen. In all other stages, the activation energy is provided by the preheated oxygen and the reaction enthalpy of TiCl4 oxidation released in the upstream stages.

Abstract: The manufacture of titanium dioxide by oxidation of titanium tetrachloride in a plug flow reactor, wherein the titanium tetrachloride is introduced into the reactor in at least two stages and is used exclusively in liquid form. The total quantity of liquid TiCl4 used is split up in several stages. A small quantity is added in the first stage in order to start combustion despite using the liquid phase. In the first phase, the activation energy required is provided solely via the preheated oxygen. In all other stages, the activation energy is provided by the preheated oxygen and the reaction enthalpy of TiCl4 oxidation released in the upstream stages.

Abstract: A process for producing a fine particulate titanium dioxide, comprising charging a fine particulate titanium dioxide powder in a resin bag, spraying water droplets having a liquid droplet diameter of 5 to 500 ?m to the powder in the bag, and closing the bag for storing the powder in the bag.

Abstract: The present invention provides a magnetic sheet with improved resistance to folding while maintaining good magnetic characteristics and reliability; a method for producing the magnetic sheet; an antenna; and a portable communication device. A magnetic sheet of the present invention includes a flat magnetic powder, and a resin binder capable of dissolving in a solvent, wherein the magnetic sheet has a gradient of the content ratio of the magnetic powder to the resin binder in a thickness direction thereof, wherein, in use, the magnetic sheet is folded so that, of the front and back surfaces thereof, one surface whose magnetic powder content is lower than that of the other is folded inward, and wherein the difference in glossiness measured at a light-incident angle of 60° between the front and back surfaces is 9.4 or more.

Abstract: Systems and methods of producing chemical compounds are disclosed. An example chemical production system includes a combustion chamber having intake ports for entry of a gas mixture. An igniter ignites the gas mixture in the intake chamber to facilitate a reaction at a high temperature and high pressure. A nozzle restricts exit of the ignited gas mixture from the combustion chamber. An expansion chamber cools the ignited gas. The expansion chamber has an exhaust where the cooled gas exits the expansion chamber. A chemical compound product is formed in the expansion chamber.

Abstract: This disclosure relates to a process for producing titanium dioxide, comprising: reacting aluminum and an alloy comprising silicon and titanium having a silicon content of at least 5%, based on the weight of the ahoy, with chlorine gas at temperatures above 190° C. to form chlorides of silicon, aluminum and titanium; adding titanium tetrachloride to the chlorides of silicon, aluminum and titanium; oxidizing the chlorides of silicon, aluminum and titanium and titanium tetrachloride; and forming titanium dioxide.

Abstract: Titanium oxide particles having a particle having a decahedral box-shape and a particle size in a range of from 1 nm to 100 nm can be selectively and efficiently produced by carrying out a method in which in a case of oxidizing titanium tetrachloride in vapor at high temperatures, it is rapidly heated and cooled, and a method, in which water vapor is used as an oxidizing gas, in combination under certain conditions.

Abstract: The invention relates to manufacturing titanium dioxide by oxidizing titanium tetrachloride by a multi-stage method, where liquid titanium tetrachloride is used in a first and gaseous titanium tetrachloride is used in a second stage. The process is energetically more favorable and offers the possibility, to a certain extent, of controlling the mean particle size of the end product.

Abstract: This disclosure relates to a flue providing improved heat transfer comprising an inner layer and an outer layer, wherein the inner layer comprises a high thermal conductivity ceramic having a thermal conductivity of at least 91 W/m-K (@300K) and a Moh's hardness of at least 6.5, and comprises a plurality of protuberances 13, depressions 14 or both; and wherein the inner layer 12 and the outer layer 11 are in substantially continuous, thermally conductive contact. Titanium dioxide particles having improved particle size, gloss, undertone, tinting strength and hiding power are famed using the above described flue.

Abstract: The manufacture of titanium dioxide by oxidation of titanium tetrachloride in a multistage method, where both oxygen and titanium tetrachloride are added in several stages. In the first stage gaseous TiCl4 is introduced into a preheated oxygen-containing gaseous stream in a stoichiometric or hyper-stoichiometric amount to produce a TiO2 containing gas suspension. In the second or further stages liquid TiCl4 and oxygen-containing gas is introduced into the TiO2 containing gas suspension to produce further TiO2.

Abstract: This disclosure relates to process for producing titanium dioxide pigment having reduced chlorides, comprising: a) reacting titanium tetrahalide vapor, rutile-forming agent and at least a stoichiometric amount of oxygen in a reactor to form a gaseous suspension comprising titanium dioxide particles; b) introducing silicon tetrachloride into the reactor at least one point downstream of the point of contact of the titanium tetrahalide, the rutile forming agent and the oxygen, and where at least 97% of the titanium tetrahalide has been converted to titanium dioxide to provide a substantially uniform encapsulation of pyrogenic SiO2 on the titanium dioxide; c) passing the gaseous suspension to a cooling conduit; d) introducing scouring material, typically selected from the group of calcined titanium dioxide and compressed titanium dioxide, and mixtures thereof, into the cooling conduit; wherein the particles of the scouring material have a diameter in the range of about 0.25 mm to about 12.

Abstract: Provided is a crystalline TiO2 powder in the form of aggregated primary particles having a variable sintering stability at a BET surface area of 70-100 m2/g and a rutile content of greater than 10% but less than or equal to 40%, and a process for preparing the crystalline TiO2 powder, which involves: introducing a TiCl4 vapor and, separately therefrom, H2 and a primary air into a mixing chamber to produce a gaseous mixture; igniting the gaseous mixture in a burner to produce a flame, which is burned into a reaction chamber to produce the crystalline TiO2 powder and gaseous substances; and separating the crystalline TiO2 powder from the gaseous substances, wherein the relative amounts of TiCl4 vapor, H2 and primary air are selected to provide crystalline TiO2 powder having the aforementioned BET surface area and rutile content, with the proviso that factor A has a value of 0.1-0.4 g/m2 in accordance within the following formula: factor A=105{[(TiCl4 vapor×H2)/(amount of air×gaseous mixture)]/BET]}.

Abstract: Disclosed herein are pigments comprising mostly rutile TiO2, wherein the mostly rutile TiO2 consists essentially of low abrasion TiO2 particles produced by introducing a metal halide into the chloride process. Further disclosed are ink, can coatings, fibers, papers, and plastics comprising the pigment. Also disclosed herein are pigments comprising the low abrasion TiO2 pigments comprising TiO2 particles which have been further heat treated at a temperature of at least about 800° C. in an oxidizing atmosphere for a time period of at least about 1 hour.

Abstract: A crystalline titanium dioxide powder, containing aggregated primary particles, wherein a BET surface area of the aggregated primary particles is from 30 to 65 m2/g, and a rutile content of a sum of crystalline modifications in the crystalline titanium dioxide is from of 50-70%.

Abstract: A method for manufacturing titanium dioxide by reacting titanium tetrachloride with an oxygen-bearing gas in a tubular reactor and subsequently cooling the titanium dioxide particle/gas mixture in a cooling section, where the gas/particle flow is caused to rotate. Titanium tetrachloride is introduced in the cross-sectional plane of the reactor, but not in the radial direction, whereby the flow velocity of the oxygen-bearing gas is more than 20 m/s. Scrub solids free the inner wall of the reactor and the reactor cooling section of TiO2 deposits, thereby achieving a better cooling performance, which produces a TiO2 pigment with a narrow particle size distribution.

Abstract: A method of preparing stable, transparent photocatalytic titanium dioxide sots is disclosed which involves thermal treatment of a suspension of amorphous titanium dioxide in the presence of certain alpha-hydroxy acids. The sots comprise titanium dioxide particles in the anatase form having a crystallite size less than about 10 nm and exhibit excellent stability and transparency at basic, neutral, and acid pH.

Abstract: Silicon titanium mixed oxide powder having the following features: BET surface area of 5 to 300 m2/g, silica content, based on the total amount of the mixed oxide powder, of ?0.1 to <0.5% by weight, titanium dioxide content, based on the total amount of the mixed oxide powder, of ?99.0% by weight, sum of the proportions of silica and titanium dioxide, based on the total amount of the mixed oxide powder, ?99.5% by weight, titanium dioxide content of the primary particles comprising intergrown rutile and anatase phases, silica content of the primary particles amorphous, is prepared by allowing the vapours of one or more, in each case oxidizable and/or hydrolyzable titanium and silicon compounds to react in a high temperature zone with oxygen and/or steam, cooling the reaction mixture after the reaction and separating off the pulverulent solid from gaseous substances.

Abstract: Systems and methods for generating nanomaterial are described wherein a reaction, for example, oxidation, for generating nanomaterial occurs in an open reaction zone which is external to the nanoparticle generator. The systems and methods minimize damage to the hot wall reactors evident in conventional systems and methods used to generate nanomaterial.

Abstract: A process for manufacturing titanium dioxide by the chloride process is provided. In one embodiment, a particle size control agent comprising an ionizing agent such as potassium chloride is introduced into the reaction zone of the oxidation reactor to control the particle size of the titanium dioxide. In a first aspect, the effectiveness of the particle size control agent in controlling the particle size of the titanium dioxide is improved by adding the particle size control agent to at least one of the reactant streams at a sufficient distance upstream of the oxidization reactor to allow the ionizing agent to efficiently ionize and the particle size control agent to thoroughly admix with the stream(s) prior to entering the reaction zone. In a second aspect, the particle size control agent comprises an ionizing agent and fumed silica. In another embodiment, the amount of alumina added to the reaction zone of the oxidization reactor is increased in order to control the particle size of the titanium dioxide.

Abstract: The invention relates to manufacturing titanium dioxide by oxidising titanium tetrachloride by a multi-stage method, where liquid titanium tetrachloride is used in a first and gaseous titanium tetrachloride is used in a second stage. The process is energetically more favourable and offers the possibility, to a certain extent, of controlling the mean particle size of the end product.

Abstract: A method of preparing stable, transparent photocatalytic titanium dioxide sols is disclosed which involves thermal treatment of a suspension of amorphous titanium dioxide in the presence of certain alpha-hydroxy acids. The sots comprise titanium dioxide particles in the anatase form having a crystallite size less than about 10 nm and exhibit excellent stability and transparency at basic, neutral, and acid pH.

Abstract: A crystalline titanium dioxide powder, containing aggregated primary particles, wherein a BET surface area of the aggregated primary particles is from 30 to 65 m2/g, and a rutile content of a sum of crystalline modifications in the crystalline titanium dioxide is from of 50-70%.

Abstract: There is described a process for preparing metal oxide particles which are substantially free of coarse tail from an oxidizing agent and a vaporous metal reactant in a flow reactor; comprising, (a) directing a flow of the metal reactant into a contacting region of the flow reactor; comprising (a) passing a flow of oxidizing agent through a high temperature zone of the flow reactor to form a flow of hot oxidizing agent and directing the flow of the hot oxidizing agent onto the contacting region of the flow reactor at a flow condition sufficient to form a reaction stream comprising a flow of hot oxidizing agent, a flow of metal reactant and a diffusive flow of the hot oxidizing agent and the metal reactant, the temperature of the hot oxidizing agent being at least sufficient to initiate oxidation of the metal reactant in the diffusive flow; (c) passing the reaction stream into a reaction zone of the flow reactor, while simultaneously introducing a flow of an upper cooling fluid substantially coaxially with the

Abstract: The disclosure relates to a process for making titanium dioxide, comprising: reacting titanium tetrachloride with oxygen by contacting the titanium tetrachloride with the oxygen in a vapor phase reactor under mixing conditions and at an elevated temperature to form a gaseous product stream containing titanium dioxide; separating the titanium dioxide from the gaseous product stream to form a process stream; analyzing the process stream to detect a concentration of titanium tetrachloride in the process stream; comparing the concentration of titanium tetrachloride detected in the process stream to an aim point concentration; and modifying the oxidation conditions to restore or maintain the concentration of titanium tetrachloride in the process stream at the aim point.

Abstract: Flame-hydrolytically produced titanium dioxide powder that is present in the form of aggregates of primary particles, and has a BET surface of 20 to 200 m²/g, a half width (HW) [nm] of the primary particle distribution of HW = a×BETf where a = 670×10?9 m³/g and ?1.3 ≤ f ≤ ?1.0 and the proportion of particles with a diameter of more than 45 &mgr;m lies in a range from 0.0001 to 0.05 wt. %. The powder is produced by a process in which a titanium halide is vapourised at temperatures of less than 200°C.

Abstract: The disclosure relates to a process for making titanium dioxide, comprising: reacting titanium tetrachloride with oxygen by contacting the titanium tetrachloride with the oxygen in a vapor phase reactor under mixing conditions and at an elevated temperature to form a gaseous product stream containing titanium dioxide; separating the titanium dioxide from the gaseous product stream to form a process stream; analyzing the process stream to detect a concentration of titanium tetrachloride in the process stream; comparing the concentration of titanium tetrachloride detected in the process stream to an aim point concentration; and modifying the oxidation conditions to restore or maintain the concentration of titanium tetrachloride in the process stream at the aim point.

Abstract: An anatase-type ultrafine particulate titanium oxide produced through a vapor-phase process, which has low chlorine content and exhibits excellent dispersibility as compared with conventional titanium oxide having a BET specific surface area comparable to that of the ultrafine particulate titanium oxide. When the ultrafine particulate titanium oxide is subjected to dechlorination, the titanium oxide satisfies the relation between BET surface area (B) and chlorine content (C) represented by the formula C?650e0.02B. The ultrafine particulate titanium oxide has a D90 of 2.5 (m or less as measured by means of laser diffraction particle size analysis. The present invention also provides a process for producing the ultrafine particulate titanium oxide.

Abstract: An anatase-type titanium oxide powder having a ratio of rutile to anatase of 10% or less and a BET specific surface area of 20 to 80 m2/g. Since the titanium oxide powder has a large specific surface area and a low ratio of rutile to anatase in comparison with a conventional titanium oxide powder and excels in dispersibility, the titanium oxide powder is suitable for various applications.

Abstract: The manufacture of titanium dioxide by oxidation of titanium tetrachloride in a multistage method, where both oxygen and titanium tetrachloride are added in several stages. In the first stage gaseous TiCl4 is introduced into a preheated oxygen-containing gaseous stream in a stoichiometric or hyper-stoichiometric amount to produce a TiO2 containing gas suspension. In the second or further stages liquid TiCl4 and oxygen-containing gas is introduced into the TiO2 containing gas suspension to produce further TiO2.

Abstract: The manufacture of titanium dioxide by oxidation of titanium tetrachloride in a plug flow reactor, wherein the titanium tetrachloride is introduced into the reactor in at least two stages and is used exclusively in liquid form. The total quantity of liquid TiCl4 used is split up in several stages. A small quantity is added in the first stage in order to start combustion despite using the liquid phase. In the first phase, the activation energy required is provided solely via the preheated oxygen. In all other stages, the activation energy is provided by the preheated oxygen and the reaction enthalpy of TiCl4 oxidation released in the upstream stages.

Abstract: This disclosure relates to a process for producing titanium dioxide, comprising: a) providing a quantity of liquid titanium tetrahalide for reacting with an oxygen-containing gas; b) vaporizing a first portion of the liquid titanium tetrahalide and reacting the titanium tetrahalide vapor and the oxygen-containing gas, in a first stage of a reaction zone, the reaction zone temperature ranging from at least about 650° C.—to form a reaction product at least containing titanium dioxide and oxygen-containing gas and passing the reaction product, more typically in the vapor phase, to at least one additional stage of the reaction zone; and c) charging at least one additional portion of the liquid titanium tetrahalide to the at least one additional stage of the reaction zone to cool the titanium dioxide and to react with the oxygen-containing gas to form additional titanium dioxide.

Abstract: Provided is a crystalline TiO2 powder in the form of aggregated primary particles having a variable sintering stability at a BET surface area of 70-100 m2/g and a rutile content of greater than 10% but less than or equal to 40%, and a process for preparing the crystalline TiO2 powder, which involves: introducing a TiCl4 vapor and, separately therefrom, H2 and a primary air into a mixing chamber to produce a gaseous mixture; igniting the gaseous mixture in a burner to produce a flame, which is burned into a reaction chamber to produce the crystalline TiO2 powder and gaseous substances; and separating the crystalline TiO2 powder from the gaseous substances, wherein the relative amounts of TiCl4 vapor, H2 and primary air are selected to provide crystalline TiO2 powder having the aforementioned BET surface area and rutile content, with the proviso that factor A has a value of 0.1-0.4·105 g/m2 in accordance within the following formula: factor A=105{[(TiCl4 vapor×H2)/(primary air×gaseous mixture)]/BET]}.

Abstract: A high photosensitivity titanium oxide composition includes a plurality of nanosize particles including titanium dioxide and titanium suboxide. The particles are substantially non-stoichiometric (TiO2-x, wherein 0.1<×<0.3 at a surface of the particles, and in the bulk of the particles x is less than at the surface), having a magnetic susceptibility value (?) of at least 0.8·10?6 cm3/g at 300 K and being at least 30% by weight rutile. A related method of forming a high photosensitivity titanium oxide composition includes the steps of providing a titanium chloride compound, such as titanium tetrachloride, an oxygen-containing gas and hydrogen, wherein a concentration of the hydrogen is in a stoichiometric excess (H2:O2) from 2.02:1 to 2.61:1. The titanium chloride compound is burned in the presence of oxygen from the oxygen-containing gas and hydrogen to form plurality of ultrafine particles comprising titanium dioxide and titanium suboxide.

Abstract: There is described an apparatus for making metal oxide particles which are substantially free of coarse tail from an oxidizing agent and a metal reactant in a flow reactor. The apparatus can be a concentric tubular flow reactor comprising a substantially funnel-shaped reactant contacting region located adjacent to a reaction zone which is able to direct a flow of a hot oxidizing agent towards a flow of the metal reactant to form a reaction stream which flows downstream into a reaction zone, whereby the hot oxidizing agent of the reaction stream is able to surround the flow of metal reactant sufficient to prevent the metal reactant from contacting the wall of the reactant contacting region and forming scale on the wall.

Abstract: Disclosed herein are pigments comprising mostly rutile TiO2, wherein the mostly rutile TiO2 consists essentially of low abrasion TiO2 particles produced by introducing a metal halide into the chloride process. Further disclosed are ink, can coatings, fibers, papers, and plastics comprising the pigment. Also disclosed herein are pigments comprising the low abrasion TiO2 pigments comprising TiO2 particles which have been further heat treated at a temperature of at least about 800° C. in an oxidizing atmosphere for a time period of at least about 1 hour.

Abstract: A crystalline titanium dioxide powder, containing aggregated primary particles, wherein a BET surface area of the aggregated primary particles is from 30 to 65 m2/g, and a rutile content of a sum of crystalline modifications in the crystalline titanium dioxide is from of 50-70%.

Abstract: Process for preparing pulverulent solids, in which one or more oxidizable and/or hydrolysable metal compounds are reacted in a high-temperature zone in the presence of oxygen and/or steam, the reaction mixture is cooled after the reaction, and the pulverulent solid is removed from gaseous substances, wherein at least one metal compound is introduced into the high-temperature zone in solid form and the evaporation temperature of the metal compound is below the temperature of the high-temperature zone.

Abstract: A process for manufacturing titanium dioxide by the chloride process is provided. In one embodiment, a particle size control agent comprising an ionizing agent such as potassium chloride is introduced into the reaction zone of the oxidation reactor to control the particle size of the titanium dioxide. In a first aspect, the effectiveness of the particle size control agent in controlling the particle size of the titanium dioxide is improved by adding the particle size control agent to at least one of the reactant streams at a sufficient distance upstream of the oxidization reactor to allow the ionizing agent to efficiently ionize and the particle size control agent to thoroughly admix with the stream(s) prior to entering the reaction zone. In a second aspect, the particle size control agent comprises an ionizing agent and fumed silica. In another embodiment, the amount of alumina added to the reaction zone of the oxidization reactor is increased in order to control the particle size of the titanium dioxide.