# US 8,784,541 B2 · Cordierite-based composite membrane coated on cordierite monolith

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- Number: US 8,784,541 B2
- Document ID: US8784541B2
- Status: Granted
- Kind: B2
- Application number: 13/293,745
- Filed: 2011-11-10
- Published: 2013-05-16
- Granted: 2014-07-22
- Earliest claimed: 2011-11-10
- Assignees: Corning Incorporated
- Applicants: Joel Edward Clinton; Yunfeng Gu
- Inventors: Joel Edward Clinton; Yunfeng Gu
- Web page: https://patentgrep.com/patent/US8784541B2

## CPC

- B01D 71/024: {Oxides}
- B01D 63/066: {with a porous block having membrane coated passages}
- B01D 67/0046: {by slurry techniques, e.g. die or slip-casting}
- B01D 69/02: characterised by their properties
- C04B 35/117: Composites
- C04B 35/195: Alkaline earth aluminosilicates, e.g. cordierite {or anorthite}
- C04B 38/0054: {the pores being microsized or nanosized}
- C04B 41/009: {characterised by the material treated}
- C04B 41/5024: {Silicates (C04B41/5022 takes precedence; silico-fluorides C04B41/5018)}
- C04B 41/85: with inorganic materials
- B01D 2323/12: Specific ratios of components used
- B01D 2325/02834: more than 0.1 and up to 1 µm
- B01D 2325/20: Specific permeability or cut-off range
- C04B 2111/00801: {Membranes; Diaphragms}
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3481: Alkaline earth metal alumino-silicates other than clay, e.g. cordierite, beryl, micas such as margarite, plagioclase feldspars such as anorthite, zeolites such as chabazite
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/602: Making the green bodies or pre-forms by moulding
- C04B 2235/606: Drying
- C04B 2235/6567: Treatment time
- Y10T 428/24149: Honeycomb-like
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Composite-membrane monoliths include a cordierite monolith having a cordierite-ceramic composite membrane bonded to surfaces thereof with a surface median pore size. The cordierite-ceramic composite membrane has membrane surfaces with a membrane median pore size of 0.3 μm or less. The cordierite-ceramic composite membrane may be a composite formed by firing the cordierite monolith subsequent to applying a cordierite-ceramic composite slip to surfaces thereof. The cordierite-ceramic slip may include cordierite particles and ceramic particles. The cordierite particles may have a cordierite median particle size smaller than the surface median pore size. The ceramic particles may have a ceramic median particle size smaller than the cordierite median particle size.

## Claims

### Claim 1

A composite-membrane monolith comprising:
a cordierite monolith having surfaces with a surface median pore size of from about 1 μm to about 15 μm; and
a cordierite-ceramic composite membrane bonded directly to surfaces of the cordierite monolith without any intervening layer between the cordierite monolith and the cordierite-ceramic composite, the cordierite-ceramic composite having membrane surfaces with a membrane median pore size of 0.3 μm or less and with small pores having small-pore sizes from 0.05 μm to 0.1 μm, the membrane median pore size and the small pores providing polymer coatability to the membrane surfaces,
wherein:
the cordierite-ceramic composite membrane is a composite having a thermal coefficient of expansion approximately equal to the thermal coefficient of expansion of the cordierite monolith and is formed from a cordierite-ceramic composite slip comprising:
from 30 wt. % to 90 wt. % cordierite particles having a cordierite median particle size from about 1 μm to about 3 μm and smaller than the surface median pore size; and
from 10 wt. % to 70 wt. % ceramic particles other than cordierite particles, the ceramic particles having a ceramic median particle size from about 0.05 μm to about 0.5 μm and smaller than the cordierite median particle size,
wherein a weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip is from 9:1 to 3:7.

### Claim 2 (depends on 1)

The composite-membrane monolith of claim 1, wherein the ceramic particles are a ceramic material selected from the group consisting of alumina, ceria, silica, zirconia, zeolite, mullite, titania, yttria, tin oxide, silicon carbide, silicon nitride, and mixtures thereof.

### Claim 3 (depends on 1)

The composite-membrane monolith of claim 1, wherein the ceramic particles are alumina particles.

### Claim 4 (depends on 3)

The composite-membrane monolith of claim 3, wherein the ceramic median particle size is from about 0.2 μm to about 0.3 μm.

### Claim 5 (depends on 1)

The composite-membrane monolith of claim 1, wherein the weight ratio of the cordierite particles to the ceramic particles in the mixture is from 9:1 to 3:7.

### Claim 6 (depends on 1)

The composite-membrane monolith of claim 1, wherein the membrane surfaces are crack-free.

### Claim 7

A method for forming a composite-membrane monolith, the method comprising:
applying a cordierite-ceramic composite slip to surfaces of a cordierite monolith, the cordierite-ceramic composite slip comprising from 30 wt. % to 90 wt. % cordierite particles and from 10 wt. % to 70 wt. % ceramic particles other than cordierite particles to form a coated cordierite monolith, the surfaces of the monolith having a surface median pore size of from about 1 μm to about 15 μm, the cordierite particles having a cordierite median particle size from about 1 μm to about 3 μm and smaller than the surface median pore size, the ceramic particles having a ceramic median particle size from about 0.05 μm to about 0.5 μm and smaller than the cordierite median particle size, the weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip being from 9:1 to 3:7; and
firing the coated cordierite monolith to form the composite-membrane monolith, the cordierite-ceramic composite slip forming, during the firing, a cordierite-ceramic composite membrane as a composite having a thermal coefficient of expansion approximately equal to the thermal coefficient of expansion of the cordierite monolith and bonded directly to the surfaces of the cordierite monolith without any intervening layer between the cordierite monolith and the cordierite-ceramic composite, the cordierite-ceramic membrane having membrane surfaces with a membrane median pore size of 0.3 μm or less and with small pores having small-pore sizes from 0.05 μm to 0.1 μm, the membrane median pore size and the small pores providing polymer coatability to the membrane surfaces.

### Claim 8 (depends on 7)

The method of claim 7, wherein the membrane surface is crack-free.

### Claim 9 (depends on 7)

The method of claim 7, wherein the ceramic particles are a ceramic material selected from the group consisting of alumina, ceria, silica, zirconia, zeolite, mullite, titania, yttria, tin oxide, silicon carbide, silicon nitride, and mixtures thereof.

### Claim 10 (depends on 7)

The method of claim 7, wherein the ceramic particles are alumina particles.

### Claim 11 (depends on 7)

The method of claim 7, wherein the firing comprises heating the coated cordierite monolith to a firing temperature of from about 900° C. to about 1300° C.

### Claim 12 (depends on 7)

The method of claim 7, wherein the cordierite-ceramic composite slip further comprises an additional ingredient selected from the group consisting of binders, dispersants, and combinations thereof.

### Claim 13 (depends on 7)

The method of claim 7, further comprising mixing a cordierite slip and a ceramic slip in appropriate proportions to form the cordierite-ceramic composite slip in which the weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip is from 9:1 to 3:7.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
mixing the cordierite particles with a vehicle, a grinding medium, and at least one ingredient selected from the group consisting of binders, dispersants, and antifoaming agents to form a cordierite mixture; and
milling the cordierite mixture until the cordierite particles therein have a median particle size from about 1 μm to about 3 μm and less than the surface median pore size of the cordierite monolith, to form the cordierite slip.

### Claim 15 (depends on 13)

The method of claim 13, further comprising:
mixing the ceramic particles with a vehicle, a binder, and a dispersant to form the ceramic slip.

### Claim 16 (depends on 13)

The method of claim 13, wherein the cordierite slip, the ceramic slip, and the cordierite-ceramic composite slip each have solids contents of from about 5 wt. % to about 30 wt. %, based on the combined weight of the cordierite particles and the ceramic particles present in the respective slip.