Apparatus and method for melt refining

Abstract

The invention relates to a system and an apparatus for melt refining, in particular aluminum or aluminum alloy melts, comprising a vessel having an outer shell or shell and a thermally insulated inner liner or wall structure; a removable lid disposed on top of the container for keeping the container sealed during operation; the container is connected with the metal fluid in the metal fluid supply flow groove, the container comprises at least one partition wall which extends upwards from the bottom of the container to the inner height of the container and divides the container into at least a first chamber and a second chamber, the first chamber has an inlet opening for receiving a metal melt from a metal supply launder portion, and the second chamber has an outlet opening in fluid connection with a downstream launder portion provided with a removable activation closure downstream of the outlet opening, the apparatus further includes a removable bypass closure disposed between the inlet opening and the outlet opening to control the flow of the metal melt, and optionally a metal level sensor to monitor the metal level in the launder portion, wherein at least one removable filter medium is arranged in at least the first chamber or in at least the second chamber at a height below a predetermined height level of the partition wall, and at least one means for degassing and refining the melt is arranged in the other of at least the first chamber or at least the second chamber.

Description

Technical Field

[0001] The present invention relates to a device and apparatus for refining a metal melt and a method for refining a metal melt. In particular, the present invention relates to a device and apparatus and a method for degassing, refining and filtering aluminum metal and aluminum alloy melts. Background Art

[0002] It is generally known to remove small inclusions from molten metals (e.g., molten aluminum) by filtering. A typical material used for such filters is porous ceramic, often referred to as CFF (ceramic foam filter). These CF (ceramic foam) filters are not easily wetted by the molten metal, and because these materials have relatively fine pores, considerable difficulty is encountered in initiating the flow of metal through the filter (priming the filter). Therefore, it is generally known to use deep filter boxes to generate sufficient metal head by gravity to force the metal through the filter.

[0003] EP 3 253 897 describes a filtration principle in which negative pressure is applied to activate from the underside of the filter medium as an alternative to the conventional gravity principle.

[0004] EP 1 081 240 describes the purification of metals by degassing the metals with negative pressure. Argon can usually be used as the process gas.

[0005] Although conventional metal refining solutions provide good quality of the metal melt to be subsequently cast, there is a desire for improved metal refining apparatus and equipment which provide a more sustainable solution and at the same time provide excellent in-line refining of the melt to be cast. Summary of the Invention

[0006] The present invention provides a solution that achieves the above-mentioned desires and has further advantages.

[0007] According to a first aspect, the present disclosure relates to a system / apparatus for refining a melt, in particular an aluminum or aluminum alloy melt, the refining system / apparatus comprising: a container having an outer shell or casing and an insulating inner lining or wall structure; a removable cover which is arranged on top of the container to keep the container sealed during operation; and a suction device for generating a negative pressure in the container during operation, the container being fluidly connected to a metal flow in a metal supply launder, the container comprising at least one dividing wall which extends upward from the bottom of the container to a preset height level of the interior height of the container and which divides the container into at least a first chamber and a second chamber, the first chamber having an inlet opening to receive the metal melt from a metal supply launder portion, the second chamber having an outlet opening which is fluidly connected to a downstream launder portion, the downstream launder portion being provided with a removable start-up closure member located downstream of the outlet opening, the apparatus further comprising a removable bypass closure member arranged between the inlet opening and the outlet opening to control the flow of the metal melt, and optionally a metal level sensor which monitors the metal level in the launder portion, wherein

[0008] At least one removable filter medium is arranged in the at least first chamber or the at least second chamber at a height below a predetermined height level of the dividing wall, and at least one device for degassing and refining the melt is arranged in the other of the at least first chamber or the at least second chamber.

[0009] The apparatus may comprise more than one dividing wall dividing the vessel into one or more additional chambers in addition to the first and second chambers, each additional chamber being provided with a removable filter medium or means for degassing and refining the melt.

[0010] In one embodiment, the device for degassing and refining the melt is arranged in the first chamber, and the removable filter medium is arranged in the second chamber.

[0011] In another embodiment, a removable filter medium is arranged in the first chamber and the device for degassing and refining the melt is arranged in the second chamber.

[0012] The device for degassing and refining the melt may include an agitator (such as a mixer or rotor) and a device for supplying process gas and, optionally, particulate material. Preferably, the device for degassing and refining the melt is a degassing rotor mounted at the bottom of the chamber. Preferably, the degassing rotor delivers process gas to the melt for refining.

[0013] The removable filter medium may be a ceramic foam filter. The ceramic foam filter may have a porosity rating of 30 to 50 ppi.

[0014] The apparatus may further comprise a metal level sensor for monitoring the metal level in the launder portion.

[0015] According to a second aspect, the present disclosure relates to a method for refining a metal melt (particularly an aluminum or aluminum alloy melt) by using the system / apparatus for melt refining according to the first aspect, the method comprising the following steps:

[0016] a) closing the removable activation closure member;

[0017] b) providing molten metal in a launder supply system;

[0018] c) generating an underpressure in the vessel by means of a suction device, thereby increasing the level of the metal melt in the at least first chamber and the at least second chamber until a predetermined metal level in the vessel allows the metal melt to flow across the at least one dividing wall;

[0019] d) starting up the equipment for degassing and refining;

[0020] e) closing the removable bypass closure; and

[0021] f) opening the removable activation closure member, thereby allowing the molten metal to flow through the at least first chamber and the at least second chamber to the downstream casting system,

[0022] The order of steps c) and d) is not mandatory and they can be performed simultaneously or partially simultaneously.

[0023] The method may include monitoring the metal level in the launder portion by a metal level sensor.

[0024] The opening of the removable start-up closure may be gradual in order to adjust the melt flow downstream of the refining device towards the casting system, thereby adjusting the residence time of the metal melt in the at least first chamber and the at least second chamber to suit the downstream casting process capabilities.

[0025] The method may include collecting exhaust gases and dust particles in a closed filtration system.

[0026] The method may further comprise the step g) of opening the removable bypass closure at the end of casting and adjusting the negative pressure to evacuate the at least first chamber and the at least second chamber.

[0027] According to a third aspect, the present disclosure relates to an apparatus for refining a metal melt (particularly an aluminum or aluminum alloy melt), the apparatus comprising: a container having an outer shell or housing and an insulating inner lining or wall structure; a removable cover arranged on top of the container to keep the container sealed during operation; and a suction device for generating a negative pressure in the container during operation, the container being configured to be fluidly connected to a metal flow in a metal supply chute, the container comprising at least one dividing wall extending upward from the bottom of the container to a preset height level of the interior height of the container and dividing the container into at least a first chamber and a second chamber, the first chamber having an inlet opening configured to be fluidly connected to a metal supply chute portion, the second chamber having an outlet opening configured to be fluidly connected to a downstream chute portion, wherein at least one removable filter medium is arranged in at least the first chamber or at least the second chamber at a height below the preset height level of the dividing wall, and at least one apparatus for degassing and refining the melt is arranged in the other of the at least first chamber or at least the second chamber.

[0028] The device may comprise more than one dividing wall dividing the vessel into one or more additional chambers in addition to the first and second chambers, each additional chamber being provided with a removable filter medium or means for degassing and refining the melt.

[0029] In one embodiment, the device for degassing and refining the melt is arranged in the first chamber, and the removable filter medium is arranged in the second chamber.

[0030] In another embodiment, a removable filter medium is arranged in the first chamber and the device for degassing and refining the melt is arranged in the second chamber.

[0031] The device for degassing and refining the melt may include an agitator (such as a mixer or rotor) and a device for supplying process gas and, optionally, particulate material. Preferably, the device for degassing and refining the melt is a degassing rotor mounted at the bottom of the chamber. Preferably, the degassing rotor delivers process gas to the melt for refining.

[0032] The removable filter medium may be a ceramic foam filter. The ceramic foam filter may have a porosity rating of 30 to 50 ppi.

[0033] According to a fourth aspect of the present disclosure, the apparatus according to the third aspect is used in-line between a furnace and a casting machine for refining, degassing, and particle removal of aluminum or aluminum alloy melt.

[0034] Surprisingly, by combining degassing, refining, and filtration in a single refining unit and apparatus, a lower molten metal height above the degassing and refining chamber can be achieved compared to conventional degassing and refining equipment, while simultaneously achieving superior, purified molten metal for casting. The lower metal height reduces the performance requirements of the suction device to maintain a sufficient level of negative pressure in the vessel. Furthermore, the volume of metal remaining when draining the refining unit can be reduced. Another advantage of the lower metal height is that the unit can be maintained through a top closure, eliminating the need for side doors for service and maintenance.

[0035] Another important advantage of the refining plant and equipment and method according to the present invention is that the degassing and refining technology and the filtration technology are combined into a single unit, thereby obtaining the purity of the filtered and degassed metal in a single step. Compared to two or more separate processing units, the refining plant and equipment with combined degassing and filtration provide better space utilization (i.e., a significantly reduced footprint), which is advantageous in narrow casting lines. The refining plant with combined filtration, degassing and refining utilizes a common housing (container), refractory lining, negative pressure system, PLC / control system, heating system, dust filter, filter frame and launder system in one unit. By combining filtration, degassing and refining in one unit and utilizing a shared negative pressure system, PLC / control system, heating system, dust filter, filter frame and launder system, the required infrastructure equipment is reduced, which again provides a more sustainable solution compared to traditional technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention is further described below with reference to the accompanying non-limiting drawings, in which:

[0037] Figure 1 Shows a side view of the refinery / equipment before start-up or after emptying.

[0038] Figure 2 A side view of a refining plant / equipment is shown with arrows indicating metal flow during a vessel filling sequence. The dotted horizontal line indicates the target metal level.

[0039] Figure 3 A side view of a refining unit / apparatus is shown with arrows indicating metal flow during steady state operation.

[0040] Figure 4 A top view of a refining unit / plant is shown with arrows indicating metal flow during steady state operation.

[0041] Figure 5 A side view of a refining plant is shown with arrows indicating the flow of metal during a vessel emptying sequence. DETAILED DESCRIPTION

[0042] The present disclosure will now be described with reference to the accompanying drawings, in which preferred exemplary embodiments of the present disclosure are shown. However, the present disclosure may be embodied in other forms, and the present invention should not be construed as limited to the embodiments and illustrative drawings disclosed herein. The disclosed embodiments are provided to fully convey the scope of the present disclosure to those skilled in the art.

[0043] In this disclosure, descriptions of a refinery also apply to corresponding structural elements of a refinery, and vice versa. Therefore, unless otherwise indicated, descriptions of a refinery should be understood as also describing the refinery. Accordingly, unless otherwise indicated, descriptions of a refinery should be understood as also describing the refinery.

[0044] In the present context, the container may also be referred to as a housing, a filter box or simply as a box, which should be understood to have the same meaning unless otherwise stated.

[0045] Throughout this application, the terms "removable start closure" and "removable bypass closure" are understood to refer to closure devices capable of stopping and / or regulating the flow of molten metal in a launder system. A closure can be a barrier or dam that can be raised and lowered to regulate or stop the flow of metal. Therefore, throughout this disclosure, the term "closure" may also be referred to as a "dam," which is intended to refer to the same structural element.

[0046] In such Figure 1 As shown (see also Figure 4 ) in an embodiment of a refining apparatus and device, the refining device includes a container 13, which may have a generally box-shaped configuration having four walls, a bottom (floor) and a top. The container may be provided with an outer shell or shell, which may be made of metal or composite material, and an inner insulating inner lining or wall construction. The inner insulating inner lining or wall construction may be made of heat-resistant insulating and refractory materials (not shown in the drawings). A removable cover 7 is provided on top of the container 13 and is configured to keep the container sealed (airtight) during operation. A suction device 11 (also referred to herein as an ejector) is arranged in the upper portion of the container for generating a negative pressure in the container during startup and operation. A dust filter is arranged on the outside of the container for filtering exhaust gas and any particles discharged with the process gas.

[0047] The vessel 13 shown in the drawings includes a dividing wall 4 extending from the bottom plate to a predetermined height lower than the vessel's interior height. The dividing wall 4 divides the vessel into two chambers: a first chamber A and a second chamber B. The vessel has an inlet opening A' for receiving metal from a metal supply launder 1 into the first chamber A, and the second chamber B is provided with an outlet opening B' for conveying purified metal to a launder 1' downstream of the refining equipment. A degassing and refining device 3 (represented in the drawings by a degassing rotor) is arranged in the first chamber A, and a filter medium 5 is installed in the second chamber B. It should be noted that the filter medium 5 can be placed in the first chamber A, and the degassing and refining device 3 can be placed in the second chamber B.

[0048] In alternative embodiments, the refining apparatus and equipment may comprise more than one dividing wall 4, so that in addition to Figure 1-5 In addition to the two chambers A and B shown in the figure, an additional refining chamber is provided in the container 13. Therefore, the refining device and equipment may include two or more chambers, each of which contains a degassing and refining device, such as a degassing rotor. The refining device and equipment may also include two or more chambers, each of which contains a filter medium 5. In refining devices and equipment that include more than two chambers A and B shown, the additional chambers containing the degassing and refining device 3 or the filter medium 5 may be arranged in parallel or in series. It should be understood that in the parallel arrangement, the additional refining chamber may have an inlet that is in fluid communication with the launder portion. In addition, the additional refining chamber may have an outlet that is in fluid communication with the downstream launder portion. The advantage of having more than two processing chambers in the refining device and equipment is that a larger volume of molten metal can be refined online in the launder system, for example for large-volume casting processes.

[0049] The vessel may be equipped with an opening 10 in the lower portion for removing any dross produced by the refining of the molten metal. Each chamber may have a separate opening 10 for dross removal. The dross removal opening may be arranged on the side of the vessel opposite the inlet opening A' and the outlet opening B' for ease of access, but other locations are also possible, for example at the lower side wall of the vessel.

[0050] The following is a list of reference numerals for the main structural components of the refining equipment and refining devices, see Figure 1-5 :

[0051] A. First chamber

[0052] B. Second chamber

[0053] A' entrance opening

[0054] B' exit opening

[0055] 1. Flow channel part (upstream)

[0056] 1' chute part (downstream)

[0057] 2 Removable bypass closures

[0058] 3 Degassing rotor

[0059] 4 partition walls

[0060] 5 Filter media

[0061] 6 Removable activation closure

[0062] 7 Sealing cover

[0063] 8 Metal level sensors

[0064] 9. Pressing tool

[0065] 10 Dregs channel opening

[0066] 11 Injectors and dust filters

[0067] 12 Refining Unit

[0068] 13 Container

[0069] 14 Predetermined Metal Levels

[0070] An example of operating a refinery and equipment will be described below with reference to the accompanying drawings. This example is not to be construed as limiting the invention.

[0071] Filling Operation

[0072] During filling of the refinery and equipment, the liquid metal is stopped from moving towards the start-up dam ( Figure 2 The removable bypass closure 2 is placed in the open position, allowing the metal melt to flow into the first chamber A and the second chamber B. The metal level sensor 8 monitors the metal level in the launder portion 1 to ensure that the metal covers the inlet opening A' and the outlet opening B'.

[0073] The negative pressure generated inside the container by the ejector 11 and the sealing gasket in the cover 7 is based on the ejector principle. With a vacuum-tight box (container), the metal passes through the inlet opening A' and the outlet opening B' (see Figure 2The level of liquid metal in the container gradually rises, forcing the metal upward through the filter medium 5 from the bottom, continuing to rise until a predetermined metal level 14 is reached within the container 13. By forcing the metal upward through the filter medium, the filter is pre-charged before the molten metal flows through the refining equipment and into a steady state above the dividing wall 4. Compared to pre-charging the filter medium using only gravity to force the molten metal from above, this bottom-up pre-charging requires only a lower height of metal above the filter medium to force the molten metal through the filter. The pre-charging force will vary depending on the coarseness of the filter medium. The hold-down tool 9 prevents the filter medium 5 from floating during the pre-charging phase. Figure 2 The arrows in the figure indicate the direction of metal flow during metal filling and filter priming.

[0074] When a predetermined negative pressure and / or metal level within the vessel is reached, the degassing rotor 3 will begin the degassing and refining process of the liquid metal, generating small bubbles and microbubbles of the supplied process gas. When the metal level reaches the target normal operating level, the removable bypass closure 2 will close, as shown by the dotted line 14, forcing the metal into the first chamber inlet A', rising upwards above the dividing wall 4, through the filter media 5 and out of the second chamber through the outlet B' to the downstream launder portion 1'.

[0075] The starter dam 6 can be opened gradually to regulate the metal flow downstream towards the casting system.The residence time of the metal in the refining device 12 (metal throughput) can be determined or regulated by the downstream casting process capabilities, ie the metal flow rate (tons / hour).

[0076] The metal level (i.e. negative pressure) is calculated based on the following formula:

[0077] dP=-rgh

[0078] in;

[0079] dP → differential pressure between the metal surface inside the container and the metal surface outside the launder

[0080] r → density of liquid metal (such as aluminum)

[0081] g → acceleration due to gravity

[0082] h → height of metal in the vessel compared to the metal level in the launder

[0083] Steady-state operation

[0084] Figure 3 and Figure 4 The arrows in the figure represent the direction of metal flow during steady-state operation of the refining device and apparatus 12. In the example, the inlet chamber A is used for degassing and refining, and the outlet chamber B is used for filtering the liquid aluminum. It will be appreciated that the order can be reversed.

[0085] The launder section 1, connected to a refining unit 12, directs the metal toward a closed bypass dam 2, forcing the liquid metal into an inlet opening A' and into a first chamber A, where a rotating degassing rotor 3 supplies process gas to the melt. Exhaust gases and dust can be collected in a closed filtration system outside the vessel. The dust filtration system is integrated with a suction device 11 (ejector), which maintains negative pressure within the vessel.

[0086] The negative pressure generated by the ejector keeps the metal at an elevated level inside the vessel so that, due to the metal flow direction, the liquid metal is forced to pass over the dividing wall 4 which separates the degassing and refining chamber and the filtration chamber, and further through the filter medium 5 which is held in place by holding means 9.

[0087] The liquid metal leaves the container through the outlet chamber opening B'.

[0088] A metal level sensor 8 monitors the metal level at the launder inlet. An operator panel with an HMI (Human Machine Interface) screen located near the unit allows for manual operation of the dam (closure member), lid, and rotor, as well as monitoring the system during operation. Operating times may vary depending on the casting system downstream of the refinery. During steady-state operation, the metal level sensor 8 and the suction device 11 for maintaining negative pressure are controlled to adjust and optimize the processing time of the molten metal in the refinery to match the capabilities of the downstream casting process.

[0089] Empty

[0090] At the end of the casting process, the bypass closure 2 opens to allow metal to drain from both chambers to the launder and casting system. This automatically empties the refining unit at the end of the operating sequence. Metal discharge is controlled by a metal level sensor 8 and by regulating the negative pressure inside the vessel. Figure 5 The arrows in show the direction of metal flow during the emptying sequence.

[0091] After complete emptying, the empty refining device (vessel) and chamber can be cleaned from the top side (with the lid 7 opened) and / or through the scum channel opening (10).

[0092] The filter medium 5 including the holding tool 9 can be lifted out together, for example by using a crane, and the apparatus can be prepared for the next casting operation.

Claims

1. An apparatus (12) for refining a melt, in particular an aluminum or aluminum alloy melt, comprising: a container (13) having an outer shell or casing and an insulating inner lining or wall structure; A removable cover (7) is provided on top of a container (13) to keep the container sealed during operation; and a suction device (11) for generating a negative pressure in the container during operation, the container (13) being fluidically connected to a metal flow in a metal supply chute (1, 1'), the container (13) comprising at least one dividing wall (4) extending upwardly from the bottom of the container (13) to a predetermined height level of the container interior and dividing the container (13) into at least a first chamber (A) and at least a second chamber (B), the first chamber having a chamber for receiving a metal flow from the metal supply chute (1, 1') An inlet opening (A') for supplying molten metal to the launder section (1), the second chamber having an outlet opening (B') which is fluidically connected to a downstream launder section (1'), the downstream launder section (1') being provided with a removable start-up closure (6) located downstream of the outlet opening (B'), the apparatus (12) further comprising a removable bypass closure (2) arranged between the inlet opening (A') and the outlet opening (B') for controlling the flow of the molten metal, and optionally a metal level sensor (8) for monitoring the metal level in the launder section (1), wherein At least one removable filter medium (5) is arranged in the at least first chamber (A) or the at least second chamber (B) at a preset height level below the dividing wall (4), and at least one device (3) for degassing and refining the melt is arranged in the other of the at least first chamber (A) or the at least second chamber (B).

2. The apparatus (12) for melt refining according to claim 1, comprising more than one dividing wall (4), which, in addition to the first chamber (A) and the second chamber (B), divides the container (13) into one or more additional chambers, each of which is provided with a removable filter medium (5) or a device (3) for degassing and refining the melt.

3. The apparatus (12) for melt refining according to any one of claims 1 to 2, wherein the device (3) for degassing and refining the melt is arranged in the first chamber (A) and the filter medium (5) is arranged in the second chamber (B).

4. The apparatus (12) for melt refining according to any one of claims 1 to 2, wherein the filter medium (5) is arranged in the first chamber (A) and the device (3) for degassing and refining the melt is arranged in the second chamber (B).

5. The apparatus (12) for melt refining according to claim 1 , wherein the device (3) for degassing and refining the melt is a degassing mixer or a degassing rotor, and a supply source for process gas and optionally a device for supplying particulate material.

6. The apparatus (12) for melt refining according to claim 5, wherein the device (3) for degassing and refining the melt is a degassing rotor (3) which supplies process gas to the melt for degassing and refining.

7. The apparatus (12) for melt refining according to any one of claims 1 to 6, wherein the filter medium (5) is a ceramic foam filter having a porosity rating of 30 to 50 ppi.

8. A method for refining a metal melt by using the apparatus (12) for melt refining according to any one of claims 1 to 7, wherein the melt is particularly aluminum or aluminum alloy melt, the method comprising the following steps: a) closing the removable activation closure member (6); b) providing a molten metal in a launder supply system (1); c) generating a negative pressure in the container (13) by means of a suction device (11), thereby increasing the level of the metal melt in the at least first chamber (A) and the at least second chamber (B) until a predetermined metal level (14) in the container (13) allows the metal melt to flow across the at least one dividing wall (4); d) starting the device for degassing and refining (3); e) closing the removable bypass closure (2), and f) opening the removable activation closure (6) thereby allowing the metal melt to flow to the casting system via the at least first chamber (A) and the at least second chamber (B).

9. A method for refining a metal melt according to claim 8, comprising monitoring the metal level in the launder section (1) by means of a metal level sensor (8).

10. The method for refining a metal melt according to claim 8 or 9, comprising gradually opening a removable start-up closure (6) to regulate the flow of metal downstream of the melt refining device (12) towards the casting system, thereby regulating the residence time of the metal melt in at least the first chamber (A) and in at least the second chamber (B) to adapt to the downstream casting process capabilities.

11. A method for refining a metal melt according to any one of claims 8 to 10, comprising collecting the exhaust gases and dust particles in a closed filtration system.

12. An apparatus (12) for refining a metal melt, in particular a melt of aluminum or an aluminum alloy, comprising: a container (13) having an outer shell or casing and an insulating inner lining or wall structure; A removable cover (7) provided on top of a container (13) to keep the container sealed during operation; and a suction device (11) for generating a negative pressure in the container during operation, the container (13) being configured to be fluidically connected to a metal flow in a metal supply launder (1, 1'), the container (13) comprising at least one dividing wall (4) extending upwardly from the bottom of the container to a predetermined height level of the container interior height and dividing the container into at least a first chamber (A) and at least a second chamber (B), the first chamber having an inlet opening (A') ), the inlet opening being configured to be fluidically connected to a metal supply launder portion (1), the second chamber having an outlet opening (B'), the outlet opening being configured to be fluidically connected to a downstream launder portion (1'), wherein at least one removable filter medium (5) is arranged in the at least first chamber (A) or the at least second chamber (B) at a height below a preset height level of a dividing wall (4), and at least one device (3) for degassing and refining the melt is arranged in the other of the at least first chamber (A) or the at least second chamber (B).

13. The device according to claim 12, comprising more than one dividing wall (4), which, in addition to the first chamber (A) and the second chamber (B), also divides the container (13) into one or more additional chambers, each of which is provided with a removable filter medium (5) or a device (3) for degassing and refining the melt.

14. The device according to claim 12 or 13, wherein the device (3) for degassing and refining the melt is a degassing mixer or a degassing rotor, and a supply source for process gas and optionally a device for supplying granular material.

15. The apparatus according to claim 14, wherein the device (3) for degassing and refining the melt is a degassing rotor installed in the bottom of the refining chamber, which supplies process gas to the melt for degassing and refining treatment.

16. Apparatus according to any one of claims 12 to 15, wherein the removable filter medium (5) is a ceramic foam filter having a porosity rating of from 30 to 50 ppi.

17. Use of the apparatus according to any one of claims 12 to 16 for use in-line between a furnace and a casting machine for refining, degassing and particle removal of aluminium or aluminium alloy melts.

Images