Abstract: A method for the uniform coating of honeycomb bodies with finely divided solid matter from a dispersion in an amount which is below that which arises during customary immersion. To this end, the honeycomb is flooded from below with dispersion, emptied after a dwell time and blown out. Filling time, filling amount, dwell time emptying time as well as the time between emptying and blowing out are measured in such a manner that in order to increase the separated amount of solid matter, filling time, dwell time, pumping-out time and the time between emptying and blowing out are increased but the filling amount is reduced.

Abstract: An apparatus and a method are disclosed for the removal and the recovery of washcoat remaining in the channels of freshly coated monolithic or honeycombed catalytic carriers. The carrier is inserted into a chamber from above and tightly fitted therein at least with the lowest part of the carrier therein. The chamber is fitted with a collection area and a runoff located thereunder. The runoff leads via a shutoff valve into a separation vessel under a vacuum. The opening and closing of the shutoff valve causes air to be aspirated through the carrier channels, which are open at the top or are gradually opened by means of a slotted slide. This action causes the washcoat remnants to be transferred into the separation vessel, where they can be collected in the sump and are then pumped off. The apparatus can be used in systems for manufacturing catalysts for cleaning exhaust gases.

Abstract: A gas-tight aluminum oxide tube having an Al.sub.2 O.sub.3 content of 98.0 to 99.8 wt-%, wherein the interior of the tube has a coating of Al.sub.2 O.sub.3 with a thickness of from 0.03 to 0.30 mm and a mean roughness R.sub.a of 2 to 10 .mu.m, is provided. Preferably, the outer surface of the tube can have a mean roughness of 1.0 to 1.5 .mu.m. Also, the coating material can contain from 15 to 30 vol-% pores and the tube material can contain from 5 to 10 vol-% pores.

Abstract: An apparatus and a method are disclosed for the removal and the recovery of washcoat remaining in the channels of freshly coated monolithic or honeycombed catalytic carriers. The carrier is inserted into a chamber from above and tightly fitted therein at least with the lowest part of the carrier therein. The chamber is fitted with a collection area and a runoff located thereunder. The runoff leads via a shutoff valve into a separation vessel under a vacuum. The opening and closing of the shutoff valve causes air to be aspirated through the carrier channels, which are open at the top or are gradually opened by means of a slotted slide. This action causes the washcoat remnants to be transferred into the separation vessel, where they can be collected in the sump and are then pumped off. The apparatus can be used in systems for manufacturing catalysts for cleaning exhaust gases.

Abstract: A free-flowing granular bitumen product containing from 0.5 to 6% by weight of a powdery coating and separating agent such as synthetic silica or carbon black is prepared by atomizing hot, liquid bitumen in a spray mixer while simultaneously introducing the powdery coating and separating agent by means of the cold air flow into the spray mixer.

Abstract: Pyrogenically prepared silicic acid is compressed by a rotary filter equipped with a pressing band.

Abstract: There is obtained an increase in the throughput in the known BMA furnace or a BMA furnace chamber without changing the construction and dimensions already present by changing the lower part of the cooling head into a short tubular heat exchanger while maintaining the necessary temperature profile for the process by arranging the ceramic tubes in the furnace chamber in closer or less close fashion and/or by using ceramic tubes having different inner and outer geometries and/or structure.

Abstract: There are prepared zeolite molded articles which also contain alkali silicate and/or alkaline earth silicate and mineral fibers and/or carbon fibers in addition to the zeolite.

Abstract: A method for compacting and/or filling of pulverulent materials into rigid or flexible containers in the course of which the pulverulent material is filled into the container with the help of a pipe in relative motion to the container, and separated from the gas, for example air, transported along with the help of a separation device which surrounds the pipe and is fitted to the container cross section. The pulverulent material is retained in the container with the help of the separation device, while the gas escapes through the gas permeable separation device.

Abstract: There are prepared zeolite molded articles which also contain alkali silicate and/or alkaline earth silicate and mineral fibers and/or carbon fibers in addition to the zeolite.

Abstract: A powdery substance, such as for example pyrogenically prepared silicon dioxide, is subjected to predensification through the utilization of centrifugal force in a centrifuge. Subsequently, the centrifuge receptacles are closed with a free flying piston. Through utilization of the centrifugal force, there is achieved through the use of the free flying piston an additional pressure which is exerted on the predetermined powdery substance.

Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.

Abstract: There is obtained an increase in the throughput in the known BMA furnace or a BMA furnace chamber without changing the construction and dimensions already present by changing the lower part of the cooling head into a short tubular heat exchanger while maintaining the necessary temperature profile for the process by arranging the ceramic tubes in the furnace chamber in closer or less close fashion and/or by using ceramic tubes having different inner and outer geometries and/or structure.

Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.

Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.

Abstract: The previously carried out internal coating of contact tubes not only required very much manual labor and was very time consuming, but it was also unsatisfactory in regard to adhesion of the contact liquid to the surface and homogenity of the catalyst. By the simultaneous action of heat on the liquid interface in the tubes during the lowering of the liquid level as well as by a specially suited apparatus for this purpose which operates according to the principle of communicating tubes there is provided the possibility of a good adhesion to the surface as well as the formation of a homogeneous layer at very little operating expense.

Abstract: The previously carried out internal coating of contact tubes not only required very much manual labor and was very time consuming, but it was also unsatisfactory in regard to adhesion of the contact liquid to the surface and homogenity of the catalyst. By the simultaneous action of heat on the liquid interface in the tubes during the lowering of the liquid level as well as by a specially suited apparatus for this purpose which operates according to the principle of communicating tubes there is provided the possibility of a good adhesion to the surface as well as the formation of a homogeneous layer at very little operating expense.