# US 4,391,918 A · Ceramic foam filter and aqueous slurry for making same

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- Number: US 4,391,918 A
- Document ID: US4391918A
- Status: Granted
- Kind: A
- Application number: 06/350,400
- Filed: 1982-02-19
- Granted: 1983-07-05
- Earliest claimed: 1981-01-22
- Assignees: Swiss Aluminium Ltd.
- Inventors: Jerry W. Brockmeyer
- Web page: https://patentgrep.com/patent/US4391918A

## CPC

- B01D 39/2093: {Ceramic foam}
- C04B 35/10: based on aluminium oxide
- C04B 35/101: Refractories from grain sized mixtures
- C04B 38/0615: {the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles (C04B38/0022 takes precedence)}
- C22B 9/023: {By filtering (filtration of aluminium C22B21/066)}
- C22B 21/066: {Treatment of circulating aluminium, e.g. by filtration (C22B21/068 takes precedence)}
- Y02P 10/20: Recycling
- 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
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention resides in an improved ceramic foam filter particularly useful for filtering molten metal and also an improved aqueous slurry for use in preparing same.

## Claims

### Claim 1

An aqueous slurry for use in preparing a ceramic foam having the following composition: 55 to 70% Al.sub.2 O.sub.3, 2 to 10% micron-sized reactive alumina, 1 to 5% montmorillonite and 1 to 10% ceramic fibers.

### Claim 2 (depends on 1)

A slurry according to claim 1 containing from 2.5 to 25% of an air setting agent which is substantially nonreactive to molten metal.

### Claim 3 (depends on 1)

A slurry according to claim 1 containing from 60 to 65% Al.sub.2 O.sub.3.

### Claim 4 (depends on 1)

A slurry according to claim 1 containing from 2 to 5% micron-sized reactive alumina.

### Claim 5 (depends on 1)

A slurry according to claim 1 containing from 1 to 3% ceramic fibers.

### Claim 6 (depends on 5)

A slurry according to claim 5 wherein said ceramic fibers are alumina-silicate fibers.

### Claim 7 (depends on 2)

A slurry according to claim 2 wherein said air setting agent is aluminum orthophosphate.

### Claim 8 (depends on 7)

A slurry according to claim 7 containing from 15 to 25% aluminum orthophosphate.