Method of making wall-flow monolith filter

• Main Authors: STEN A. WALLIN, FREDRICK W. VANCE
• Format: Patent
• Language: English
• Published: 05.11.2002
• Edition: 7
• Subjects: ARTIFICIAL STONE; BLASTING; CEMENTS; CERAMICS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; LIGHTING; LIME, MAGNESIA; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; REFRACTORIES; SEPARATION; SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS, SLAG, OR MIXTURESCONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER; SLAG; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; TREATMENT OF NATURAL STONE; WEAPONS; WORKING CEMENT, CLAY, OR STONE

A ceramic honeycomb wall-flow filter is prepared by plugging channels in a ceramic honeycomb comprised of clay by a method comprising the following. First, a mixture comprised of a dispersing liquid and ceramic powder is formed. Second, the mixture is inserted into at least one channel of a green ceramic honeycomb that is comprised of a clay to form a plugged green ceramic honeycomb wherein the dispersing liquid essentially fails to swell the clay. Alternatively, the mixture is inserted into a calcined ceramic honeycomb to form a plugged calcined ceramic honeycomb. Finally, the plugged green or calcined ceramic honeycomb is heated to a temperature sufficient to sinter the plugged green ceramic honeycomb to form a porous sintered plugged ceramic honeycomb. The method is particularly useful for simultaneously making the plugs and discriminating layers in the channels. The outlet plugs on have the same composition as the discriminating layer and preferably have a different composition from the inlet plugs.