Cordierite refractory compositions and method of forming same

Claim 1

A ceramic refractory fired composition having high thermal shock resistance and a low thermal coefficient of expansion consisting essentially of magnesia, alumina, and silica in crystalline form with cordierite as the major phase and mullite as the minor phase and having an amount of Na 2 O and K 2 O which is not in excess of about 0.14% by weight of the composition.

Claim 10

A method of making a refractory ceramic catalyst support having a plurality of parallel fluid passages extending therethrough which comprises forming a mixture, in % by weight, of from about 32.6 to 39.0% talc, from about 24.7 to 29.7% clay, from about 13.1 to 19.5% calcined kyanite, and from about 11.8 to 26.5% alumina, the mixture being such that after firing the composition is substantially on the straight line defined by compositions on the triaxial diagram of the magnesia-alumina-silica system consisting essentially of about the following percent by weight of the indicated constituents: point B -- 35.2% Al 2 O 3 , 51.2% SiO 2 , 13.6% MgO point C and D -- 42.2% Al 2 O 3 , 45.7% SiO 2 , 12.1% MgO point E -- 46.7% Al 2 O 3 , 42.1% SiO 2 , 11.2% MgO, the major crystalline phase being cordierite and the minor crystalline phase being mullite, and the amount of Na 2 O and K 2 O contained in the body being less than about 0.14% by weight, dry mixing the powder constituents for a period sufficient to obtain a uniform blending, adding a uniform solution of an organic binder material in water from which the salts have been removed and wet mixing the materials for an additional period to achieve uniform wetting, the amount of the water being such as to achieve a batch consistency which enables extrusion while enabling the extruded body to stand without sag in the green state, feeding the materials through an extruder to form the desired catalyst support green body, drying said body to remove substantially all the water therein, firing the dry body at a peak temperature of from about 2550° to 2570° F. for a period of from 3 to 4 hours and finishing the fired body to the desired size by removal of the end portions to eliminate any collapsed fluid passage portions.

Claim 11

A method of making a refractory ceramic catalyst support having a plurality of parallel fluid passages extending therethrough which comprises forming a mixture, in % by weight, of from about 32.6 to 39.0% talc, from about 24.7 to 29.7% clay, from about 13.1 to 19.5% calcined kyanite, and from about 11.8 to 26.5% alumina, the mixture being such that after firing the composition is substantially on the straight line defined by compositions on the triaxial diagram of the magnesia-alumina-silica system consisting essentially of about the following percent by weight of the indicated constituents: point B -- 35.2% Al 2 O 3 , 51.2% SiO 2 , 13.6% MgO point C and D -- 42.2% Al 2 O 3 , 45.7% SiO 2 , 12.1% MgO point E -- 46.7% Al 2 O 3 , 42.1% SiO 2 , 11.2% MgO, the major crystalline phase being cordierite and the minor crystalline phase being mullite, and the amount of Na 2 O and K 2 O contained in the body being less than about 0.14% by weight, dry mixing the powder constituents for a period sufficient to obtain a uniform blending, adding a uniform solution of an organic binder material in water from which the salts have been removed and wet mixing the materials for an additional period to achieve uniform wetting, the amount of the water being such as to achieve a batch consistency which enables extrusion while enabling the extruded body to stand without sag in the green state, feeding the materials through an extruder to form the desired catalyst support green body, drying said body to remove substantially all the water therein, firing the dry body at a peak temperature of from about 2550° to 2570° F. for a period of from 3 to 4 hours and finishing the fired body to the desired size by removal of the end portions to eliminate any collapsed fluid passage portions.