Abstract:
The invention relates to a method for the synthesis of a powder, that comprises the following consecutive steps: A) preparing a mother liquor containing: i) an oxide base constituent or a precursor of said base constituent and an additional constituent of the formula MC, said additional constituent including: - an agent M selected from the group of oxo-anions, anions of elements of column 17 of the periodic table, hydroxide OH'' and mixtures thereof; - and a complement C, the complement being inorganic when said agent is hydroxide OH'; or ii) an oxide base constituent or a precursor of said base constituent including an agent M selected from the group of oxo-anions, anions of elements of column 17 of the periodic table and mixtures thereof; B) preparing from said mother liquor and by hydrothermal means, a sol containing raw particles having a maximum size higher than 10 nm and lower than 250 nm and even lower than 100 nm; C) washing the sol in order to obtain, after a potential drying step, a powder including more than 99.3% of said base constituent in mass percent based on the dry material.
Abstract:
Die Erfindung betrifft feinteilige Erdalkalititanate sowie ein Verfahren zu ihrer Herstellung durch Umsetzung von Erdalkalimetallverbindungen mit Titandioxidpartikeln. Die Titandioxidpartikel weisen eine BET-Oberfläche von mehr als 50 m2/g auf. Die Titandioxidpartikel können einen sehr geringen Gehalt an Sulfat, Chlorid und Kohlenstoff aufweisen. Die Umsetzung kann bei einer Temperatur unter 700° C erfolgen. Das Erdalkalititanat kann eine BET-Oberfläche von 5 bis 100 m2/g aufweisen. Vorzugsweise enthält es keine Hydroxylgruppen im Kristallgitter. Das Erdalkalititanat kann zur Herstellung mikroelektronischer Bauteile verwendet werden.
Abstract:
A process for preparing calcium aluminate from aluminum dross comprising crushing (10) the dross and extracting solubles therefrom with water in a digester (14). The brine so obtained is processed in a crystallizer (32) to obtain fluxing (32 (a)) materials contained therein, and the insolubles are furnaced (22) to separate the free aluminum metal therefrom. To prevent undesirable reactions from occurring in the digester (14) which result in the production of hazardous and noxious products, the pH in the digester is controlled in the range of from about 5 to about 8, by withdrawing a magnesium chloride-containing stream (32 (b)) from the crystallizer (32 (c)) and introducing it into the digester (14).
Abstract:
Provided is an integrated layer (10 nm to 500 μm) of highly oriented halogenated graphene having a formula C 6 Z x O y , wherein Z is a halogen element selected from F, Cl, Br, I, or a combination thereof, x = 0.01 to 6.0, y = 0 to 5.0, and x + y ≤ 6.0. The integrated layer has halogenated graphene crystals having an inter-planar spacing d 002 of 0.35 nm to 1.2 nm (more typically 0.4 - 1.0 nm) as determined by X-ray diffraction. The integrated layer has multiple constituent graphene halide planes that are substantially parallel to one another along one direction having an average deviation angle of these graphene halide planes less than 10 degrees.
Abstract:
A method for producing a polysilane includes a disproportionation reaction of a methylchlorodisilane mixture to form chlorine-containing oligosilane, a substitution reaction of the chlorine atoms contained in the oligosilane by the reaction with a primary amine and a cross-linking reaction of the oligosilanes using a chain former to form polysilanes. The obtained polysilanes are infusible and are very suitable for being spun to form green fibers and processed to form silicon carbide fibers and fiber composites. The method is characterized in that it can be carried out cost-effectively and quickly and with very high yields.