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AssigneeDegussa AG
InventorsDietrich Arntz, Gunter Prescher, Werner Burkhardt, Johannes Heilos, Reinhard Manner
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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. The applied coating is densified by continuing the mechanical and fluidizing mixing motion, the material is then dried in a continuing gas stream and heat-treated, if appropriate after decomposition of an added pore-former.
A process for preparing abrasion-resistant coated particulate catalysts formed of an inert particulate support which has a rough surface and a particle size range of 0.5 to 6 mm and a coating of catalytically active material enclosing said inert support and anchored to said support, said process comprising
Dependencies are inferred from the claim text.