# US 9,518,307 B2 · Method for the production of a refractory filter

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- Number: US 9,518,307 B2
- Document ID: US9518307B2
- Status: Granted
- Kind: B2
- Application number: 14/283,672
- Filed: 2014-05-21
- Published: 2014-09-25
- Granted: 2016-12-13
- Earliest claimed: 2014-05-21
- Assignees: Foseco International Limited
- Applicants: Foseco International Limited
- Inventors: Friedhelm Demey; Renate Jahre; Hans Riethmann; Mario Arruda; Antonio Cassara; Raphael Neto; Fabio De Oliveira; Sueli Pereira; Kazuhiro Nakano
- Web page: https://patentgrep.com/patent/US9518307B2

## CPC

- C22B 9/023: {By filtering (filtration of aluminium C22B21/066)}
- B01D 39/2093: {Ceramic foam}
- C04B 35/524: obtained from polymer precursors, e.g. glass-like carbon material
- C04B 35/565: based on silicon carbide
- C04B 35/6263: {characterised by their solids loadings, i.e. the percentage of solids}
- C04B 38/0022: {obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors}
- 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)}
- B01D 2239/10: Filtering material manufacturing
- C04B 2111/00793: {as filters or diaphragms}
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/3826: Silicon carbides
- Y02P 10/20: Recycling
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method for the production of closed edge filters suitable for filtering molten metal and filters made by such a method. The method comprises: providing a reticulated foam substrate having at least one first surface for forming a side face of the filter and two opposed second surfaces for forming the through-flow faces of the filter; applying a liquid comprising an organic coating component to the first surface; solidifying the organic coating component to form a filter precursor having a volatilizable coating on the first surface; impregnating the filter precursor with a slurry comprising particles of a refractory material, a binder and a liquid carrier; and drying and firing the impregnated filter precursor to form the filter having a closed edge.

## Claims

### Claim 1

A refractory foam filter comprising a three-dimensional network of strands of refractory material and having at least one side face and two opposed through-flow faces, the at least one side face having a unitary closed edge, wherein the closed edge comprises cavities enclosed within the edge and the filter is capable of withstanding temperatures above 500° C., and wherein substantially all of the cavities enclosed within the edge are located along a line which is substantially parallel to the edge of the filter.

### Claim 2 (depends on 1)

The filter according to claim 1, wherein the unitary closed edge has a thickness of less than 1 mm.

### Claim 3 (depends on 1)

The filter according to claim 1, in which the cavities are significantly longer in a direction parallel to the side face than they are wide in a direction perpendicular to the side face.

### Claim 4 (depends on 1)

The filter of claim 1, in which the unitary closed edge has a thickness of less than 0.5 mm.

### Claim 5 (depends on 1)

The filter of claim 1, wherein the ratio of the thickness of the unitary closed edge to the thickness of the strands is from 0.5 to 2.