GB2313069A - Molten metal filtration apparatus - Google Patents
Molten metal filtration apparatus Download PDFInfo
- Publication number
- GB2313069A GB2313069A GB9610458A GB9610458A GB2313069A GB 2313069 A GB2313069 A GB 2313069A GB 9610458 A GB9610458 A GB 9610458A GB 9610458 A GB9610458 A GB 9610458A GB 2313069 A GB2313069 A GB 2313069A
- Authority
- GB
- United Kingdom
- Prior art keywords
- molten metal
- vessel
- filtration apparatus
- filters
- metal filtration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 37
- 239000002184 metal Substances 0.000 title claims abstract description 37
- 238000001914 filtration Methods 0.000 title claims abstract description 33
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 239000011819 refractory material Substances 0.000 claims abstract description 11
- 239000011810 insulating material Substances 0.000 claims description 6
- 239000004411 aluminium Substances 0.000 abstract description 21
- 229910052782 aluminium Inorganic materials 0.000 abstract description 21
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 21
- 239000002245 particle Substances 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 6
- 239000006260 foam Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 229910000838 Al alloy Inorganic materials 0.000 description 4
- 230000037452 priming Effects 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000005350 fused silica glass Substances 0.000 description 2
- 239000011236 particulate material Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004901 spalling Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/02—Refining by liquating, filtering, centrifuging, distilling, or supersonic wave action including acoustic waves
- C22B9/023—By filtering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/01—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements
- B01D29/03—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements self-supporting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
- B01D29/52—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/76—Handling the filter cake in the filter for purposes other than for regenerating
- B01D29/80—Handling the filter cake in the filter for purposes other than for regenerating for drying
- B01D29/84—Handling the filter cake in the filter for purposes other than for regenerating for drying by gases or by heating
- B01D29/843—Handling the filter cake in the filter for purposes other than for regenerating for drying by gases or by heating by direct contact with a fluid
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
Molten metal filtration apparatus comprises a vessel 1 having an inlet 5 and an outlet 6 for the molten metal, and a lid 7 having heating means 8 therein for heating the interior of the vessel 1. The vessel 1 further has a plurality of filter housings 11, 11', each containing a filter 12, 12' of bonded particulate refractory material in the form of a plate. The plates are held in place by refractory gaskets 13, 13'. The filter housings 11, 11' are located in the vessel 1 in relation to the heating means 8 so that the filters 12, 12' can be preheated from above by the heating means 8. The vessel 1 is formed from various layers of refractory material 3, 4. The heating means 8 may be in the form of a gas fired hot burner or it may be electrical. The lid 7 of the vessel is able to rotate 90{ from its closed position. The molten metal filtration apparatus is used for filtering molten aluminium.
Description
MOLTEN METAL FILTRATION APPARATUS
This invention relates to molten metal filtration apparatus containing a plurality of filters of bonded particulate material and particularly, to molten metal filtration apparatus for filtering molten aluminium and aluminium alloys.
In the aluminium industry it is common practice to filter molten aluminium and molten aluminium alloys prior to casting.
Various types of filter have been used but the most commonly used filters are ceramic foams, which are produced by impregnating polyurethane foam with a slurry containing refractory material and a binder, and then drying and firing the impregnated foam, and filters of bonded particulate material made by mixing together refractory material and a binder, forming the mixture to a desired shape, for example, a plate or a tube, by pressing, and heating the formed shape.
Bonded particulate filters offer a number of advantages over ceramic foams when used as filters for molten aluminium. They are generally of higher strength and since they have lower porosity, have a more tortuous flowpath and do not contain blocked pores, they give a greater filtration efficiency in terms of removal of oxide and other solids from the aluminium.
However, as bonded particulate filters are more dense than ceramic foams they require significantly more preheating in order to achieve complete priming of the filters at the start of filtration and optimum filtration performance. When used in the form of plates in an aluminium cast-house filtration apparatus, it is necessary to preheat the plates to permit molten aluminium to flow through the plates without solidifying. This preheating of the plates is usually done by direct flame impingement on the bottom face of the plates and because the bonded particle filter plates have poor thermal shock resistance, spalling of the filter plates can result.
In order to maximise through-put of molten aluminium, aluminium cast-houses, which filter molten aluminium alloys for wrought alloy production, are now using filtration apparatus containing two or more filter plates. However, the filter plates which are currently used are produced in ceramic foam and because of the problems associated with priming bonded particle filter plates, such filter plates have not been used.
It has now been found that bonded particle filter plates can be successfully used in multi-filter filtration apparatus if the apparatus has means for preheating the filter plates from above and the apparatus has sufficient height above the top of the filter plates to initiate metal flow through the filter plates.
According to the invention there is provided molten metal filtration apparatus comprising a vessel having an inlet and an outlet for the molten metal, a lid having heating means therein for heating the interior of the vessel and the vessel having a plurality of filter housings, each containing a filter of bonded particulate refractory material in the form of a plate, the filter housings being located in the vessel in relation to the heating means so that the filters can be preheated from above by the heating means, and the filter housings being located in the vessel in relation to the inlet and the outlet such that the height of the top of the vessel above the filters is sufficient to initiate molten metal flow through the filters, whereby molten metal passes downwardly through the filters and out of the vessel through the outlet.
Since the inner surface of the vessel must withstand molten metal such as aluminium and should not contaminate the metal, the vessel should either be made from or be lined with a refractory material which meets those requirements. In order to reduce heat loss through the walls of the vessel a lining of refractory heat-insulating material may be installed between the shell of the vessel and the refractory lining.
Similarly, to reduce heat losses the lid may also be lined with a thermally insulating material.
Examples of suitable refractory materials for forming the inner, metal contacting surface of the vessel are fused silica based castable materials having a density of approximately 1.8 g/cm3.
Examples of thermally insulating materials for the walls of the vessel and for the lid are refractory castable materials having a density of below 1.4 g/cm3 and also ceramic fibre containing materials in block, blanket or module form.
In order to permit easy access to the interior of the vessel, for example, to remove used filters and replace them with new filters, the lid is preferably mounted so that it can rotate through 90" from the closed position.
The heating means is preferably a high velocity gas fired hot air burner having means for automatically controlling heat up time and temperature during preheating of the filter plates. However, other means, such as electrical heating, could be used instead. When using controlled heating means installed in the lid of the filtration apparatus, operators do not need to monitor the heating because there is no danger of the filters being damaged by preheating as there is when using direct flame impingement, and the filters can be left to preheat for any desired length of time.
The filter plates may be made from refractory particles of silicon carbide or alumina or any other refractory material which is suitable for use in the metal which is to be filtered. The particles may be ceramically bonded to form plates using binders which produce a bond which is also resistant to the metal to be filtered.
Suitable filter plates are available from Metaullics Systems.
The nomenclature used for indicating the porosity of such filters is the grit or grain size, the nominal average pore diameter decreasing as the grit number increases. The filter plates are produced commercially in a range of porosities of from 6 grit to 24 grit. Filter plates of 16 to 20 grit size are preferred. The filter plates are also commercially available in a range of sizes from approximately 200 mm square to approximately 600 mm square but can be produced in other sizes if desired to suit a particular application.
The filters can be held in place in the housings by means of a refractory gasket.
In order that the filter plates are each heated uniformly to the same degree, the housings holding the filter plates are preferably located on the vessel so that the filter plates are coplanar.
The size of the vessel and the number of housings and filter plates will be dependent on the volume of metal which it is desired to filter. However, a single multi-filter filtration apparatus will not usually contain more than a maximum of four filter plates.
The multi-filter filtration apparatus of the invention, when used to filter molten aluminium or molten aluminium alloys, is more efficient than similar apparatus containing ceramic foam filters and the apparatus of the invention overcomes the priming problems normally associated with bonded particle filter plates.
The invention is illustrated with reference to the accompanying drawings in which :
Figure 1 is a diagrammatic side elevation of molten metal filtration apparatus of the invention for filtering molten aluminium; and
Figure 2 is a top view of the molten metal filtration apparatus of Figure 1 with its lid removed.
Referring to the drawings, an apparatus for filtering molten aluminium consists of a vessel 1 having a steel casing 2, a lining of refractory heat-insulating material 3 and an inner refractory lining 4, formed from a material which will withstand molten aluminium such as a fused silica castable material. The vessel has an inlet trough for the molten aluminium 5, an outlet for the molten aluminium 6 and a lid 7 having a refractory heat-insulating lining. The lid 7 has a high velocity gas fired hot air burner 8 consisting of a gas burner 9 and a fire box 10, positioned so that in use hot air is directed downwardly into the interior of the vessel 1. The vessel also has two filter housings 11, 11' formed in the refractory lining 4 and both the filter housings 11, 11' contain a bonded particle filter plate 12, 12' consisting of ceramically bonded alumina and held in place by a refractory gasket 13, 13'. The filter housings 11, 11' are formed in the vessel 1 so that the filters 12, 12' are coplanar and are located such that the height of the top of the vessel 1 in relation to the filters 12, 12' is sufficient to initiate molten metal flow through the filters 12, 12' when the vessel 1 is filled with molten aluminium.
Before the apparatus is used to filter molten aluminium, the filters 12, 12' are preheated by hot air from the gas fired burner 8 using a predetermined heating cycle so that the lower face of the filters 12, 12' reach a minimum of 700"C to ensure priming of the filters. Molten aluminium is then poured into the vessel 1 through the inlet trough 5 so as to fill the vessel 1, and is filtered downwardly through the filters 12, 12', and the filtered aluminium exits from the vessel 1 through the outlet 6.
Claims (11)
1. Molten metal filtration apparatus comprising a vessel (1) having an inlet (5) and an outlet (6) for the molten metal, a lid (7) having heating means (8) therein for heating the interior of the vessel (1) and the vessel (1) having a plurality of filter housings (11, 11l, each containing a filter (12, 125 of bonded particulate refractory material in the form of a plate, the filter housings (11, 111 being located in the vessel (1) in relation to the heating means (8) so that the filters (12, 12) can be preheated from above by the heating means (8), and the filter housings (11, 11) being located in the vessel (1) in relation to the inlet (5) and the outlet (6) such that the height of the top of the vessel (1) above the filters (12, 121 is sufficient to initiate molten metal flow through the filters (12, 12), whereby molten metal passes downwardly through the filters (12, 12) and out of the vessel (1) through the outlet (6).
2. Molten metal filtration apparatus according to Claim 1 wherein the vessel (1) is made from a refractory material which will withstand molten metal.
3. Molten metal filtration apparatus according to Claim 1 wherein the vessel (1) is lined with a refractory material (4) which will withstand molten metal.
4. Molten metal filtration apparatus according to Claim 3 wherein the vessel (1) has a lining of refractory heat-insulating material (3) between its shell (2) and the refractory lining (4).
5. Molten metal filtration apparatus according to any one of
Claims 1 to 4 wherein the lid (7) is lined with a thermally insulating material.
6. Molten metal filtration apparatus according to any one of
Claims 1 to 5 wherein the lid (7) is mounted so that it can rotate through 90" from its closed position.
7. Molten metal filtration apparatus according to any one of
Claims 1 to 6 wherein the heating means is a high velocity gas fired hot air burner (8).
8. Molten metal filtration apparatus according to any one of
Claims 1 to 6 wherein the heating means is electrical.
9. Molten metal filtration apparatus according to any one of
Claims 1 to 8 wherein the filters (12, 12,) are held in place in the housing (11, 115 by means of a refractory gasket (13, 135.
10. Molten metal filtration apparatus according to any one of
Claims 1 to 9 wherein housings (11, 11,) are located on the vessel (1) so that the filter plates (12, 12,) are coplanar.
11. Molten metal filtration apparatus as claimed in Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9610458A GB2313069A (en) | 1996-05-18 | 1996-05-18 | Molten metal filtration apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9610458A GB2313069A (en) | 1996-05-18 | 1996-05-18 | Molten metal filtration apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9610458D0 GB9610458D0 (en) | 1996-07-24 |
| GB2313069A true GB2313069A (en) | 1997-11-19 |
Family
ID=10793956
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9610458A Withdrawn GB2313069A (en) | 1996-05-18 | 1996-05-18 | Molten metal filtration apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2313069A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999044719A2 (en) * | 1998-03-04 | 1999-09-10 | Les Produits Industriels De Haute Temperature Pyrotek Inc. | Improved molten metal filtration and distribution device and method for manufacturing the same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4067731A (en) * | 1975-07-18 | 1978-01-10 | Southwire Company | Method of treating molten metal |
| GB1521979A (en) * | 1975-04-29 | 1978-08-23 | Alusuisse | Methods and apparatus for filtering metal melts |
| GB2090153A (en) * | 1980-12-27 | 1982-07-07 | Bridgestone Tire Co Ltd | Molten metal filtering device |
| US4964993A (en) * | 1984-10-16 | 1990-10-23 | Stemcor Corporation | Multiple-use molten metal filters |
-
1996
- 1996-05-18 GB GB9610458A patent/GB2313069A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1521979A (en) * | 1975-04-29 | 1978-08-23 | Alusuisse | Methods and apparatus for filtering metal melts |
| US4067731A (en) * | 1975-07-18 | 1978-01-10 | Southwire Company | Method of treating molten metal |
| GB2090153A (en) * | 1980-12-27 | 1982-07-07 | Bridgestone Tire Co Ltd | Molten metal filtering device |
| US4964993A (en) * | 1984-10-16 | 1990-10-23 | Stemcor Corporation | Multiple-use molten metal filters |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999044719A2 (en) * | 1998-03-04 | 1999-09-10 | Les Produits Industriels De Haute Temperature Pyrotek Inc. | Improved molten metal filtration and distribution device and method for manufacturing the same |
| WO1999044719A3 (en) * | 1998-03-04 | 1999-11-11 | Prod Ind De Haute Temperature | Improved molten metal filtration and distribution device and method for manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9610458D0 (en) | 1996-07-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |