Pore size control in cordierite ceramic

Claim 1

A porous, fired ceramic product having at least 70 volume percent cordierite crystals and at least 20 percent of open pores larger than 10 microns in diameter and being made by the process of: 1. formulating a batch composition using ceramic raw materials analytically containing Al 2 O 3 , MgO and SiO 2 , at least one being -200 Tyler mesh and selected from the group consisting of: 1 to 17% pyrophillite, 1 to 40% kyanite, 1 to 20% quartz, and 1 to 20% fused silica, each of the ceramic raw materials selected in an effective amount for yielding at least 70 volume percent cordierite in the product upon sintering the batch composition; 2.

Claim 13

A method of inducing coarse porosity in a sintered cordierite product such that at least 20% of open pores are larger than 10 microns in diameter by the old method of formulating a batch of ceramic raw materials analytically containing Al 2 O 3 , SiO 2 and MgO, blending the batch together with forming aids into a plastically formable batch, forming the batch into a green ceramic body, and sintering the green ceramic body to bring about the development of cordierite crystals wherein the improvement comprises formulating the batch using at least one pore size control raw material being -200 Tyler mesh and selected from the group consisting of: 1-17% pyrophillite, 1-40% kyanite, 1-20% quartz, and 1-20% fused silica each of the selected ceramic raw materials and the selected pore control raw materials being employed in an effective amount for together forming a batch which when sintered yields a product with at least 70 percent volume percent cordierite phase.

Claim 14

A method of inducing coarse porosity in a sintered cordierite product such that at least 20% of open pores are larger than 10 microns in diameter by the old method of formulating a batch of ceramic raw materials analytically containing Al 2 O 3 , SiO 2 and MgO, blending the batch together with forming aids into a plastically formable batch, forming the batch into a green ceramic body, and sintering the green ceramic body to bring about the development of cordierite crystals wherein the improvement comprises formulating the batch using at least one pore size control raw material being -200 Tyler mesh and selected from the group consisting of: 1-17% pyrophillite, 1-40% kyanite, 1-20% quartz, and 1-20% fused silica each of the selected ceramic raw materials and the selected pore control raw materials being employed in an effective amount for together forming a batch which when sintered yields a product with at least 70 percent volume percent cordierite phase.