Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90±15 m2/g, wherein the aggregates display an average surface area of 10000 to 20000 nm2, an average equivalent circle diameter (ECD) of 90 to 130 nm and an average circumference of 1000 to 1400 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1810 to 1890° C. is obtained. Dispersion containing the pyrogenically produced silicon dioxide powder.

Abstract: A high dispersible hydrophobic fine silica powder can be made, wherein the silica powder has hydrophobicity of more than 50%, triboelectrostatic charge of more than ?500 ?C/g, decomposition rate of an organic group on the powder surface of less than 15%, transmittance of a 5% alcoholic dispersion liquid of more than 40% preferably, and a specific surface area of more than 200 m2/g. This high dispersible hydrophobic fine silica powder can be made by mixing a hydrophobic agent comprising a volatile organic silicon compound in the gas state with a fine silica powder in a fluidized bed type reaction vessel at the time of a hydrophobic treatment, and controlling a gas flow rate to more than 5.0 cm/sec at the time of this mixing.

Abstract: An aqueous dispersion having a pH value of between 3 and 7 containing 1 to 35 wt. % of a pyrogenically produced silicon-aluminium mixed oxide powder with a specific surface area of 5 to 400 m2/g, wherein the proportion of aluminium oxide in the powder is between 90 and 99.9 wt. % or between 0.01 and 10 wt. %, the surface of the powder comprises zones of aluminium oxide and silicon dioxide and the powder exhibits no signals for crystalline silicon dioxide in an X-ray diffractogram. Said dispersion may be used for the chemical-mechanical polishing of conductive, metallic films.

Abstract: A surface modified inorganic oxide powder is provided, which includes inorganic oxide particles having a surface modified with a mixed solution, which includes an organopoly-siloxane and a silane compound, in the presence of an acid or a base.

Abstract: The amorphous-silica particle having 0.1–0.7 ?m of the average particle diameter, 5–30 m2/g of the specific surface area, less than 40% of the dispersion coefficient, and 20 ?C/m2 of the absolute value of the triboelectrostatic charge, can be obtained, by setting flame temperature to more than melting point of silica, raising the silica concentration in a flame, and staying the generated silica particle in the flame for a short time to be grew up. Since this silica particle has a particle shape being near a true sphere, and a particle size of said particle is remarkably uniform, so it is suitable for a filler of a semiconductor sealing agent or various materials, etc. In addition, since said particle has strong electrification, it is also suitable for an outer or an inner additional agent of a toner for an electronic photograph, a photo conductor material for a electronic photograph, and a material of an electric charge transportation layer, etc.

Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90±15 m2/g, wherein the aggregates display an average surface area of 10000 to 20000 nm2, an average equivalent circle diameter (ECD) of 90 to 130 nm and an average circumference of 1000 to 1400 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1810 to 1890° C. is obtained. Dispersion containing the pyrogenically produced silicon dioxide powder.

Abstract: A high dispersible hydrophobic fine silica powder can be made, wherein the silica powder has hydrophobicity of more than 50%, triboelectrostatic charge of more than ?500 ?C/g, decomposition rate of an organic group on the powder surface of less than 15%, transmittance of a 5% alcoholic dispersion liquid of more than 40% preferably, and a specific surface area of more than 200 m2/g. This high dispersible hydrophobic fine silica powder can be made by mixing a hydrophobic agent comprising a volatile organic silicon compound in the gas state with a fine silica powder in a fluidized bed type reaction vessel at the time of a hydrophobic treatment, and controlling a gas flow rate to more than 5.0 cm/sec at the time of this mixing.

Abstract: A surface modified inorganic oxide powder is provided, which includes inorganic oxide particles having a surface modified with a mixed solution, which includes an organopoly-siloxane and a silane compound, in the presence of an acid or a base.

Abstract: Firstly, a powder matrix is kept in a fluent state, said powder matrix consisting of a first oxide having an absorbed water amount of 0.1 to 50%, an averaged particle diameter of 0.005 to 0.5 &mgr;m and a surface hydroxyl group number of 0.1 to 25 &mgr;mol/m2. Then, one or both of a halide and an alkoxide including metal or semi-metal identical with or different from the metal or semi-metal constituting said first oxide is allowed to contact with said powder matrix kept in the fluent state, by means of an inert carrier gas, and then they are heated at a temperature of from 25 to 800° C., to thereby coat said powder matrix by a coating layer consisting of a second oxide. Further, a reaction by-product consisting of one or both of a hydrogen halide or an alcohol generated by said contacting is heated at a temperature of from 200 to 1000° C. within the inert carrier gas to thereby eliminate the reaction by-product.

Abstract: The amorphous-silica particle having 0.1-0.7 &mgr;m of the average particle diameter, 5-30 m2/g of the specific surface area, less than 40 of the dispersion coefficient, and 20 &mgr;C/m2 of the absolute value of the triboelectrostatic charge, can be obtained, by setting flame temperature to more than melting point of silica, raising the silica concentration in a flame, and staying the generated silica particle in the flame for a short time to be grew up. Since this silica particle has a particle shape being near a true sphere, and a particle size of said particle is remarkably uniform, so it is suitable for a filler of a semiconductor sealing agent or various materials, etc. In addition, since said particle has strong electrification, it is also suitable for an outer or an inner additional agent of a toner for an electronic photograph, a photo conductor material for a electronic photograph, and a material of an electric charge transportation layer, etc.

Abstract: A surface modified inorganic oxide powder is provided, which includes inorganic oxide particles having a surface modified with a mixed solution, which includes an organopoly-siloxane and a silane compound, in the presence of an acid or a base.

Abstract: Firstly, a powder matrix is kept in a fluent state, said powder matrix consisting of a first oxide having an absorbed water amount of 0.1 to 50%, an averaged particle diameter of 0.005 to 0.5 &mgr;m and a surface hydroxyl group number of 0.1 to 25 &mgr;mol/m2. Then, one or both of a halide and an alkoxide including metal or semi-metal identical with or different from the metal or semi-metal constituting said first oxide is allowed to contact with said powder matrix kept in the fluent state, by means of an inert carrier gas, and then they are heated at a temperature of from 25 to 800° C., to thereby coat said powder matrix by a coating layer consisting of a second oxide. Further, a reaction by-product consisting of one or both of a hydrogen halide or an alcohol generated by said contacting is heated at a temperature of from 200 to 1000° C. within the inert carrier gas to thereby eliminate the reaction by-product.

Abstract: An ultrafine particle silicon dioxide which comprises silicon dioxide powders in the range of ultrafine particles having a BET specific surface area of 350 m2/g or more and has a ratio of BET/CTAB specific surface areas of 0.6 to 1.1, a number average of primary particle diameters of 1 to 20 nm, void volume measured with a mercury porosimeter of 0.1 to 1.0 ml/g and linseed oil absorption of 350 to 600 ml/100 g. According to the present invention, the ultrafine particle silicon dioxide can provide various kinds of polymers with excellent mechanical strength and transparency as a filler.

Abstract: By treating metal oxide fine particles having a specific surface area of 5 to 500 m.sup.2 /g with a silane coupling agent and then further treating the fine particles with a reactive group-terminated organopolysiloxane, the organopolysiloxane is stably bonded to the surface of the powder particles, to thereby improve stability of the modifying effect against the elapse of time and durability.

Abstract: Gallium-containing waste is chlorinated in the presence of gallium trichloride from the beginning. By this procedure, gallium is more efficiently chlorinated and gallium trichloride is more easily separated from other chlorides and recovered.

Abstract: For detachably holding a lance in axial alignment with the mouth or top opening of a metallurgical furnace, use is made of a chuck through which the lance can be inserted upwardly for communication with an outlet conduit extending downwardly from a vessel defining a pressure-tight air or oxygen chamber therein. A packing box supported under the outlet conduit houses means for establishing pressure-tight communication between the lance and the outlet conduit. The vessel, the packing box and the chuck are all bracketed to a carriage movable along a vertical track for causing up-and-down motion of the lance into and out of the furnace mouth. According to another embodiment of the invention, means are further provided for rotating the lance while the latter is inserted into the furnace.