Abstract: Pyrogenically, especially flame-hydrolytically produced zirconium dioxide powder with a specific surface area between 20 and 200 m2/g, a primary particle size between 7 and 100 nm, a tamped density of the deacidified and non-deacidified zirconium dioxide between 40 and 150 g/l with Sears numbers of the deacidified and non-deacidified zirconium dioxide between 1 and 20 ml/2 g and with a chlorine content of the deacidified zirconium dioxide less than 0.6% by weight. These are produced by evaporating zirconium halides, mixing the vapors alone or together with a carrier gas in a burner with air, oxygen, nitrogen and hydrogen, causing the gases to react with each other in a flame in a closed burner chamber, cooling off the waste gases and the zirconium dioxide in a heat exchanger unit, separating the waste gases from the zirconium dioxide and removing any halide remnants adhering to the zirconium dioxide by a heat treatment with moistened air.

Abstract: A boron oxide-silicon dioxide mixed oxide which has a BET surface of less than 100 m2g, and optionally containing oxides of aluminium, titanium or zirconium, is prepared pyrogenically by flame hydrolysis. The mixed oxide is used in glass making.

Abstract: Disclosed is a method for the purification of exhaust air and/or effluents, which may be exhausted, for example, from auto painting units or furniture lacquering units, involving contacting the air and/or effluents with a molded body. The molded body is made from dealuminated zeolite Y and at least one binder, which may be, for example, bentonites, kaolins, sepiolites or attapulgites, and having a hydrophobic factor of from 1.5 to 6.0, wherein a slurry of the binder in water does not exceed a pH of 10 and wherein the molded body is calcined at 850° to 1100° C. The molded body is produced by a process involving mixing pulverulent dealuminated zeolite Y with at least one binder, optionally with the addition of a lubricant and/or a pore former, and optionally with water or an organic solvent, moulding the resulting mass to form a molded body, and drying and calcining the molded bodies.

Abstract: A boron oxide-silicon dioxide mixed oxide which has a BET surface of less than 100 m.sup.2 g, and optionally containing oxides of aluminium, titanium or zirconium, is prepared pyrogenically by flame hydrolysis. The mixed oxide is used in glass making.

Abstract: Pyrogenically produced silica having a specific surface of less than 90 m.sup.2 /g, preferably of less than 60 m.sup.2 /g, and a DBP absorption of less than 60 wt. % (less or equal to 57.30 ml dibutyl phthalate/100 g) is produced by vaporizing silicon halides and/or organosilicon halides, mixing the vapors with a carrier gas, heating the mixture to temperatures definitely above the boiling point of the silicon-halogen compound, mixing with hydrogen and combustion in a known manner in a burner.

Abstract: Thermally split zirconium silicate is produced such that the crystalline zirconium dioxide embedded in an amorphous silica phase exhibits an average grain or particle size (d.sub.50 value) in a range of 0.5 .mu.m to 3.0 .mu.m and a specific surface (BET) in a range of 3 to 15 m.sup.2 /g. The zirconium dioxide produced by this method is particularly suited for the production of zirconium silicate pigments with improved color characteristics. The thermally split zirconium silicate is also particularly well suited for processes used in the obtention of zirconium dioxide. The method of producing the thermally split zirconium silicate includes melting zirconium silicate in an induction melting furnace and cooling off a free falling stream of melt by blowing on it with a gas and/or spraying it with water.

Abstract: Molecular sieves are modified by an ion exchange process where metal cations are introduced into the molecular sieves by means of solid state ion exchange. The solid state ion exchange can be carried out as follows: a weighed amount of calcined and activated zeolite is intimately mixed with a precalculated amount of PtCl.sub.2, PdCl.sub.2, RhCl.sub.3, CuCl.sub.2, V.sub.2 O.sub.5 or another compound of the noble metals (e.g., corresponding halides or oxides), the solids mixture is then heated in a current of inert gas (e.g., a current of helium gas or of nitrogen) to temperatures of 400.degree. to 600.degree. C., then cooled down to room temperature and subsequently reduced in a current of hydrogen for 10 to 14 hours at 280.degree. to 350.degree. C. in order to produce small metal clusters from the cationically introduced metal.

Abstract: Molecular sieves are modified by an ion exchange process where metal cations are introduced into the molecular sieves by means of solid state ion exchange. The solid state ion exchange can be carried out as follows: a weighed amount of calcined and activated zeolite is intimately mixed with a precalculated amount of PtCl.sub.2, PdCl.sub.2, RhCl.sub.3, CuCl.sub.2, V.sub.2 O.sub.5 or another compound of the noble metals (e.g., corresponding halides or oxides), the solids mixture is then heated in a current of inert gas (e.g., a current of helium gas or of nitrogen) to temperatures of 400.degree. to 600.degree. C., then cooled down to room temperature and subsequently reduced in a current of hydrogen for 10 to 14 hours at 280.degree. to 350.degree. C. in order to produce small metal clusters from the cationically introduced metal.

Abstract: A method is disclosed for the semi-continuous melting of ceramic material by means of inductive melting in high-frequency and medium-frequency induction melting furnaces whose melting coil surrounds a sintering crust crucible and contains a run-out channel. In the method, melt is periodically run out and material to be melted is supplied to the crucible so as to replace the material removed preferably so as to maintain a constant level. An intensively cooled channel is used as a run-out device. For the melt broaching, the melt nose is grasped from below by way of an automatically controllable broaching lance of a broaching device and raised. The broaching lance is then advanced between the bottom of the channel and the solidified melt until the sintering crust is pierced. The method permits a reliable and economic management of the process and the maintenance of the quality of the melted products.

Abstract: Several method is of preparing formed spherical polymeric complexes of metals of the 8th subgroup of the periodic system with ligands of an organosiloxane copolycondensate optionally cross-linked by means of cross-linking agents containing Si, Ti, Zr and/or Al (statistical, block-shaped or mixed) with special posttreatment stages are described.

Abstract: Molecular sieves are modified by an ion exchange process where metal cations are introduced into the molecular sieves by means of solid state ion exchange. The solid state ion exchange can be carried out as follows: a weighed amount of calcined and activated zeolite is intimately mixed with a precalculated amount of PtCl.sub.2, PdCl.sub.2, RhCl.sub.3, CuCl.sub.2, V.sub.2 O.sub.5 or another compound of the noble metals (e.g., corresponding halides or oxides), the solids mixture is then heated in a current of inert gas (e.g., a current of helium gas or of nitrogen) to temperatures of 400.degree. to 600.degree. C., then cooled down to room temperature and subsequently reduced in a current of hydrogen for 10 to 14 hours at 280.degree. to 350.degree. C. in order to produce small metal clusters from the cationically introduced metal.

Abstract: A method is disclosed for the semi-continuous melting of ceramic material by means of inductive melting in high-frequency and medium-frequency induction melting furnaces whose melting coil surrounds a sintering crust crucible and contains a run-out channel. In tile method, melt is periodically run out and material to be melted is supplied to the crucible so as to replace the material removed preferably so as to maintain a constant level. An intensively cooled channel is used as a run-out device. For the melt broaching, the melt nose is grasped from below by way of an automatically controllable broaching lance of a broaching device and raised. The broaching lance is then advanced between the bottom of the channel and the solidified melt until the sintering crust is pierced. The method permits a reliable and economic management of the process and the maintenance of the quality of the melted products.

Abstract: Silicon-aluminum mixed oxide powder which is flamehydrolytically produced and has a composition of 65 to 85% by weight Al.sub.2 O.sub.3, remainder SiO.sub.2 and an amorphous structure, in which each primary particle contains components of SiO.sub.2 and of Al.sub.2 O.sub.3, the primary particles are between 7 and 80 nm, preferably 10 and 40 nm in size and the specific surface of the powder is between 20 and 200 m.sup.2 /g. The powder is used for the production of mullite and sintered compacts manufactured from it.

Abstract: A heat-insulator consisting ofa) A finely distributed, powdery or fibrous substance,b) A microporous casing andc) A gas- and watertight, metal-free casing.The heat insulator is manufactured by optionally drying the powdery or fibrous substance, optionally bringing it into a microporous casing, optionally pressing it and then optionally drying it. The powdery substance is then brought with the microporous casing into a gas- and watertight, metal-free casing. This gas- and watertight casing is optionally evacuated and sealed.

Abstract: Silicon-aluminum mixed oxide powder which is flame-hydrolytically produced and has a composition of 65 to 85% by weight Al.sub.2 O.sub.3, remainder SiO.sub.2 and an amorphous structure, in which each primary particle contains components of SiO.sub.2 and of Al.sub.2 O.sub.3, the primary particles are between 7 and 80 nm, preferably 10 and 40 nm in size and the specific surface of the powder is between 20 and 200 m.sup.2 /g. The powder is used for the production of mullite and sintered compacts manufactured from it.

Abstract: A preferably platelike form body for use as heat insulation, consisting of:a) a finely divided, powdery or fibrous material,b) a microporous casing andc) a gas and watertight casing.The form body is produced by optionally drying the powdery or fibrous material, optionally placing it into a microporous casing, optionally pressing it and then optionally drying it. Then, the powdery material is placed with the microporous casing into a gas and watertight casing. This gas and watertight casing is optionally evacuated and sealed.

Abstract: Disclosed are shaped organopolysiloxanes containing sulfonate groups and consisting of units(O.sub.3/2 Si--R.sup.1 --SO.sub.3.sup.-).sub.x M.sup.x+ (I)in which R.sup.1 is an alkylene group, x is a number from 1 to 4 depending on M, and M is hydrogen or a monovalent to tetravalent optionally complex metal ion, and the valencies of the silicon linked oxygen atoms are saturated by silicon atoms of other groups (I) or by crosslinking silicon and aluminum compounds, the ratio of the silicon atoms in (I) to the silicon and aluminum atoms of the crosslinker being from 1:4 to 1:20. The organopolysiloxanes containing sulfonate groups are present in the form of spherical particles with a diameter of 0.01 to 3 mm, a specific surface of 0.1 to 1200 m.sup.2 /g, a specific pore volume of 0.01 to 6 ml/g, and an apparent density of 50 to 1000 g/l. Also disclosed are processes for the production of the shaped sulfonated organopolysiloxanes and to their use as a solid acid catalyst.

Abstract: Formed spherical polymeric complexes of metals of the 8th subgroup of the periodic system with ligands of an organosiloxane copolycondensate optionally cross-linked by means of cross-linking agents containing Si, Ti, Zr and/or Al (statistical, block-shaped or mixed). This copolycondensate consists of the units ##STR1## in which R.sup.1 -R.sup.4 =R.sup.5 -Si ##STR2## in which R.sup.5 =alkylene with C.sub.1 -C.sub.10 directly bound to P or N, cycloalkylene with C.sub.5 -C.sub.8 or ##STR3## The ratio between the number of moles of units (II) and the number of moles of bound metal atoms is 1:1 to 1.000 to 1 and the ratio between units (I) and (II) is preferably 10:90 to 95:5 mole %.The polymeric complex compounds are present macroscopically as spherical particles with a diameter of 0.01. to 3.0 mm, a BET surface of >0 to 1000 m.sup.2 /g, a specific pore volume of 0.01 to 6.5 ml/g, and a bulk density of 50 to 1000 g/l.

Abstract: Inclusion pigments are discolored having zirconium silicate as a casing component and chromium (III) oxide (Cr.sub.2 O.sub.3) as a discrete, included color compound. The included Cr.sub.2 O.sub.3 has a D.sub.50 value in the range of 0.1 to 3.0 .mu.m and a brilliant light green color. Contrary to non-included Cr.sub.2 O.sub.3 of identical value, the pigments of the present invention may be used for the preparation of decorations without problems and difficulties in their application and maintaining sharp lines and contours. The pigments are suitable for direct pressing and high temperature firing processes. They are prepared by fusing a mixture of zirconium dioxide, silicon dioxide, mineralizators and chromium oxide.

Abstract: Thermally split zirconium silicate is produced such that the crystalline zirconium dioxide embedded in an amorphous silica phase exhibits an average grain or particle size (d.sub.50 value) in a range of 0.5 .mu.m to 3.0 .mu.m and a specific surface area (BET) in a range of 3 to 15 m.sup.2 /g when the silica is removed by leaching. The zirconium dioxide produced by this method is particularly suited for the production of zirconium silicate pigments with improved color characteristics. The thermally split zirconium silicate is also particularly well suited for processes used in the obtention of zirconium dioxide. The method of producing the thermally split zirconium silicate includes melting zirconium silicate in an induction melting furnace and cooling off a free falling stream of melt by blowing on it with a gas and/or spraying it with water.