Patent ID: 6048490
Filing Date: 2000-04-11
Classification: B01J,C04B

Abstract:
A method of producing a cordierite body, the method comprising:a) providing cordierite-forming raw materials selected from the group consisting of talc, calcined talc, MgO-forming component, magnesium aluminate spinel, SiO.sub.2 -forming component, Al.sub.2 O.sub.3 -forming component, kaolin, calcined kaolin, mullite, and combinations thereof, chosen such that the quantity R is less than about 10.156, wherein R is defined as0.140 (wt. % mullite powder)+0.433 (wt. % SiO.sub.2 powder)+0.0781 (wt. % alpha Al.sub.2 O.sub.3 powder)(mean particle size of alpha Al.sub.2 O.sub.3 powder)+0.0872 (wt. % Al(OH).sub.3 powder)(mean particle size of Al(OH).sub.3 powder)+0.00334 (wt. % SiO.sub.2 powder)(wt. % magnesium aluminate spinel powder)+2.330 log.sub.10 (1+(wt. % MgO-forming component)(wt. % calcined kaolin))-0.244 (wt. % MgO-forming component)-0.167 (wt. % dispersible high surface area Al.sub.2 O.sub.3 -forming component)+1.1305 (heating time measured in hours at maximum temperature,wherein the MgO-forming component is selected from the group consisting of MgO, Mg(OH).sub.2, MgCO.sub.3, and combinations thereof,the SiO.sub.2 -forming component is selected from the group consisting of quartz, fused silica, colloidal silica powder, colloidal silica sol, silicon organometallic compounds, and combinations thereof;the Al.sub.2 O.sub.3 -forming component is selected from the group consisting of alpha-alumina, Al(OH).sub.3, dispersible high surface area Al.sub.2 O.sub.3 forming source, and combinations thereof,the SiO.sub.2 powder is selected from the group consisting of quartz, fused silica, and combinations thereof,wt. % is based on the total weight of the raw materials,and the particle size is measured in micrometers;b) intimately blending the raw materials with an effective amount of vehicle and forming aids to impart plastic formability and green strength to the raw materials and form a plastic mixture therefrom;c) forming said raw materials into a green body;d) drying the green body; ande) heating said green body from room temperature up to a maximum temperature of about 1360.degree. C. to 1435.degree. C. at an average heating rate of at least about 315.degree. C. per hour and holding at said maximum temperature for about 0.05 to 4.4 hours, wherein the total heating time from room temperature to the end of the hold at the maximum temperature is less than about 4.5 hours, to produce a body that is predominately cordierite, having a mean coefficient of thermal expansion from about 25.degree. C. to 800.degree. C. of less than about 15.times.10.sup.-7 .degree.C..sup.-1 in at least one direction.