Keramische Mehrschichtenfilter und Verfahren zu deren Herstellung

DE 19857591 A UPAB: 20000801 NOVELTY - A ceramic laminated filter has a support layer and at least one layer of finer ceramic particles. The surface of all particles is (partly) wetted by a material which wets the surface well, has (almost) the same coefficient of thermal expansion as the particles, causes no or little change in their size, morphology and composition/crystal structure and bonds them, with only slight or partial reduction in the amount and size of pores. DETAILED DESCRIPTION - The ceramic laminated filter has two or more layers of the same or different ceramic materials with different particle sizes in the individual layers. One is a support layer and at least one is a layer of ceramic material with smaller particle size. The surface of all the ceramic particles is (partly) wetted by a material(s) which wets the surface well and has (almost) the same coefficient of thermal expansion as the particles, causes no or little change in the particle size, morphology and composition/crystal structure of the powder, bonds the particles at points and/or the surface and causes only a slight or partial but no more than about 50% reduction in the amount and size of the pores between the particles. An INDEPENDENT CLAIM is also included for the production of the filter comprising making at least two ceramic slips from at least two ceramic powders of the same or different composition but different particle size, with the addition of conventional molding and sintering aids. The ceramic particles are wetted with a wetting material that wets the particles well on heating, added in powder form, in such amounts that there is little reduction in the amount and size of pores. The slips are made into layer(s) and dried and another layer of finer particles is applied after (partial) drying. The superimposed layers are heated to form bonds from the wetting material at points and/or areas between the ceramic particles. USE - The filter is used e.g. for separating oil-in-water emulsions, clarifying beer, purifying and separating gases and separating liquid-solid mixtures. ADVANTAGE - Despite having individual layers of different particle size, all layers of the filter can be sintered simultaneously, making production more cost-effective