Abstract: A process for the preparation of boehmitic alumina compounds having a purity of, at least, 99.95% Al.sub.2 O.sub.3. The compounds produced according to the invention have a pore radii in the range of 3 to 100 nm. The preparation of such compounds is carried out by, first, obtaining an alumina suspension from a neutral aluminum alkoxide hydrolysis and, then, aging the alumina suspension in an autoclave, preferably, at a steam pressure of 1 to 30 bar, corresponding to a temperature of 100.degree. C. to 235.degree. C., for between 0.5 and 20 hours. The aging step of the invention is preferably carried out with stirring at a peripheral speed of 1 to 6 m/s.

Abstract: The invention relates to a process for the preparation of a high-purity, thermally stable catalyst carrier based on aluminosilicate with 0.5 to 50% by weight SiO.sub.2 by mixing an aluminum compound with a silicic acid compound in an aqueous medium, and subsequently drying or calcining the product obtained. The aluminum component used is a C.sub.2 to C.sub.20+ aluminum alkoxide hydrolyzed with water and purified by means of ion exchangers. Simultaneously or subsequently orthosilicic acid purified by means of ion exchangers is added to the aluminum compound.

Abstract: A composition for use as a paint detackifying and sedimentation agent is disclosed, which includes 60 to 80% by weight of alumina Al.sub.2 O.sub.3) in pseudoboehmite or boehmite form, either in X-ray amorphous form or with a crystallite size of 20 to 150 A. The composition of the invention may include foam inhibitors, or other conventional additives. A process for use of the composition of the invention is also disclosed in which the composition is added as a 5-30% aqueous dispersion or in dry form to the circulating water of a paint spraying booth and used in a quantity of 1 to 10% by weight, based on 1 kg of the paint to be detackified.

Abstract: The invention is directed to a process for the production of aluminium alcoholates by reacting aluminium in comminuted form with an excess of an aliphatic C.sub.3 to C.sub.10 alcohol in which the aluminium is supplied to the reactor from above and is brought into contact with an aluminium alcoholate/alcohol mixture above a perforated plate or grid tray (screen) in the reactor. The aluminium, or preferably a suspension of alcohol and finely divided aluminium, is supplied to the reactor and fed from above to a bubble bed made of a mixture of aluminium alcoholate and alcohol in the area of the perforated plate, whereby the mixture of aluminium alcoholate and alcohol in the reactor sump or overflowing in part is recycled to the reactor over the bubble bed and optionally, preferably with the aluminium suspension, returned from above to the reactor and in part is isolated. There is also described a reactor suitable for carrying out the process.

Abstract: For the preparation of spheroidal alumina, an alumina sol having a solids content of more than 20 to 40% by weight of alumina is prepared from alumina hydrate, which consists of boehmite/pseudo-boehmite, by thorough stirring in aqueous dilute acid, and the alumina sol is caused in the presence of 1 to 10% by weight of urea to drop into a forming column whose top portion is filled with a liquid hydrocarbon and whose bottom portion is filled with an aqueous solution of ammonia and which is held at room temperature, and the thus formed spheroidal particles are dried and activated. The resultant spheroidal particles may also be subjected to a per se known aging treatment.

Abstract: A highly porous alumina having a large surface area and a low bulk density is prepared by hydrolyzing an aluminum alcoholate at a temperature of 40.degree. to 90.degree. C. in an aqueous solution containing 8 to 30% by weight of a compound which upon drying or activating splits out NH.sub.3 and/or CO.sub.2, there being used 0.5 to 3 parts by weight of the compound per 10 parts of aluminum alcoholate. The aluminum oxyhydrate paste formed by the hydrolysis is separated from the alcohol phase, in a given case is also purified, and subsequently dried or activated.

Abstract: Formed products are made from aqueous aluminum oxyhydrate by peptizing the aqueous aluminum oxyhydrate with an acid and then subsequently adding a dilute solution of ammonia or an ammonia yielding compound following by extrusion, drying and calcining.