High surface area ceramic catalysts and the manufacture thereof
A process for making a ceramic catalyst material includes mixing a catalyst precursor material with a mineral particulate to form a mixture; adding a binder, silicon carbide, and a parting agent to the mixture to form unfired spheroids; and heating the unfired spheroids at a temperature effective to oxidize the silicon carbide and the catalyst precursor material to form the ceramic catalyst material. In another embodiment, the process includes the addition of a catalyst metal oxide salt to an aluminosilicate hydrogel aggregate mixture. Once the mixture sets, the set mixture is heated to a temperature to effective to produce a high surface area ceramic catalyst material.
1 . A process for making a porous ceramic catalyst material comprising:
mixing a catalyst precursor material with a mineral particulate to form a mixture;
adding a binder, silicon carbide, and a parting agent to the mixture to form unfired spheroids; and
heating the unfired spheroids at a temperature effective to oxidize the silicon carbide and the catalyst precursor material to form the porous ceramic catalyst material.
2 . The process of claim 1 , wherein the binder is selected from a group consisting of bentonite starch, polyvinyl alcohol, cellulose gum, polyvinyl acetate, sodium lignosulphonate and mixtures thereof.
3 . The process of claim 1 , wherein the parting agent is selected from a group consisting of magnesium oxide, zircon, diaspore high alumina clays, surface metal oxides and mixtures thereof.
4 . The process of claim 1 , wherein the mineral particulate is a silicate.
5 . The process of claim 1 , wherein the mineral particulate is selected from a group consisting of orthoclase, nepheline, hornblende, diopside, titanite, apatite, biotite, kaolinite, analcite, plagioclase, pyroxene, magnetite, quartz, perlite, apatite, biotite, pyrite, vermiculite and mixtures thereof.
6 . The process of claim 1 , wherein the catalyst precursor is a metal oxide salt.
7 . The process of claim 6 , further comprising adding an aqueous solution containing ions selected from a group consisting of hydroxides, chlorides, phosphates, sulfates, ammonium, sodium, lithium, and mixtures thereof.
8 . The process of claim 1 , wherein the catalyst precursor is an oxide of a metal selected from a group consisting of ruthenium, platinum, palladium, osmium, iridium, rhodium, titanium, lead, zirconium, niobium, manganese, tantalum, tungsten, tin, and mixtures thereof.
9 . The process of claim 1 , wherein the catalyst metal is 0.01 to 5.00% by weight of the mixture.
10 . A process for forming a porous ceramic catalyst material, the process comprising:
mixing a binder, aggregates, and a catalyst precursor, wherein the binder comprises an alkali, alumina, and silica;
forming a rigid composite of the mixture; and
heating the rigid composite to a temperature greater than 500° C. to form the porous ceramic catalyst material.
11 . The process of claim 10 , wherein the aggregates comprise zircon, mullite, fused silica, kyanite, alumina, chromite, rutile, ilmenite, sillimanite, forsterite, olivine, talc, refractory clays, beryl, feldspar, perlite, vermiculite, and mixtures thereof.
12 . The process of claim 10 , wherein the binder is greater than 10% by weight of the composite.
13 . The process of claim 10 , alumina and silica are at a mole ratio of 0.7 to 4.20, respectively.
14 . The process of claim 10 , wherein the catalyst precursor is an oxide of a metal.
15 . The process of claim 10 , wherein forming the composite comprises dispersing air into the mixture to form a foamed mixture.
16 . The process of claim 10 , wherein forming the composite comprises dispersing a blowing agent into the mixture, wherein heating the mixture generates gas to form the porous ceramic catalyst material.