NO333626B1 - Induction device and method for treating molten materials - Google Patents

Abstract

A flow acting or stirring apparatus (500) comprises electromagnetic induction apparatus in the form of a generally rectangular box (501) coupled to an inclined end wall (502) of a cradle or port (503) of the apparatus (500), generally having a cross-section of a rectangular , straight triangle. The inclined wall (503) slopes 45 (relative to the vertical wall (504) and the horizontal wall (505) of the cradle or support (503). The way the cradle or gate (503) can be connected to the vertical end wall (600) of the furnace (601) can be seen in Figure 3. The door or cradle (503) may be attached to the wall (600) of the furnace (601) by providing an aperture 602 of appropriate size and using conventional refractory techniques to attach. The electromagnetic induction apparatus (501) is suitably connected to the end wall (503) and acts in use to produce molten metal circulation in the furnace in a vertical plane.

Description

The invention relates to a flow-causing device or stirring device as stated in claim 12, and a method for recycling or refining scrap materials as stated in claim 14.

Scrap metal recycling is increasing and, consequently, considerable efforts have been made to improve the efficiency of recycling processes, including scrap metal smelting.

Furnaces for melting and refining metallic materials, e.g. aluminum or other materials are known. Such furnaces are often used to recycle scrap metal. Various proposals have been made to improve the smelting and refining, e.g. by stirring the molten metal (and possibly alloying additions) and stirring the mixture of molten metal and additions of solid metal materials in the melting in the furnace. Stirring of molten metal helps to increase the efficiency of the melting process by distributing the heat throughout the melt and also speeding up the melting of solid scrap material and/or additives in the melt.

In this context, it is known to provide a stirring device in the form of an electromagnetic induction unit (in the form of a linear motor) which can be placed under the furnace in a horizontal plane near the bottom wall of the furnace under the melt. The magnetic field produced by the induction motor acts through a relatively thick plate at the bottom of the furnace and effectively stirs the molten material slowly in a horizontal plane in an attempt to distribute the heat evenly through the molten mass. It is also known to use mechanical stirring devices in such ovens to produce a similar stirring effect. However, it is believed that such treatment of molten metal has disadvantages, at least in some applications. E.g. when added scrap metal material or alloy additions, e.g. silicone is introduced into the furnace on top of the melt, the stirring effect from the electromagnetic induction motor will not significantly contribute to mixing the new scrap metal material/additions evenly through the melt. Often the scrap material/additive will be quite light (especially a silicone additive) and will simply float on the surface of the melt when stirred in a horizontal plane, rather than e.g. to be drawn down into the molten metal where it can be melted much faster and more efficiently. Again, scrap metal in the form of aluminum drinking cups will simply float to the top of the melt and be oxidized rather than being mixed with the melt bath and efficiently recycled. In the document US 5462572 A, an apparatus is described for inducing a vertical flow of molten metal by means of an electromagnetic induction means. The document US 3709476 A deals with a means for induction stirring of a metal melt. The documents US 4589637 A and US 4397687 A also deal with stirring and flow generation in metal melts.

Stirrers with induction motors are quite slow, operating at 1 Hz. The design limitations of such motors require that a fairly deep magnetic field be sent through the entire height of the molten material in the furnace, so that the horizontal, circular stirring action takes place throughout the entire molten material rather than e.g. only in the lower layer of materials. In order to achieve such a depth of the magnetic field, this must come at the expense of a higher stirring speed. A much lower stirring speed is achieved if the material could be stirred using a magnetic field of reduced depth.

When mechanical stirring devices are used, these will burn out quite quickly and have to be replaced and will not yet be able to be used to work in a way that helps draw down scrap metals, additives that are introduced at the top of the melt.

Again, it is assumed that there will be no problems in the extraction of the molten metal material after it has undergone treatment in the furnace. The usual way of extracting molten metal materials can be dangerous for the operator. A plug may be provided at the bottom of the furnace which can be removed so that the molten metal material can flow through it and thus be extracted from the furnace, or the furnace must be tipped to pour the melt from the furnace. In all cases, it is assumed that the level of the operator involves a risk of damage to the molten metal material, which is not necessary if the extraction of molten material from the furnace is improved.

It is an object of the invention at least to reduce one or more of the previously mentioned disadvantages in connection with the treatment of molten materials and/or to produce an improved stirring apparatus system, stirring arrangement, moving or transfer apparatus, furnace or method.

According to a first aspect of the invention, a flow influence or stirring device is provided which causes a downward and/or upward flow of molten metal material and/or circulation of molten metal material in a vertical plane, e.g. in an oven.

Furthermore, according to the invention, a furnace or a chamber for treating molten metal is provided in combination with at least one flow agent or stirring device as required in the immediately preceding section.

Furthermore, according to the invention, a furnace or a chamber is provided for treating molten metal where at least one flow-causing device or stirring device which, when used, causes a downward and/or upward flow of molten metal material and/or circulation of molten metal material in a vertical plane.

The flow inducing or stirring device can also, in use, produce a horizontal flow of molten metal material and/or circulation of molten metal in a horizontal plane, e.g. between two or more chambers of an oven, e.g. a side oven.

Typically, the flow causing or stirring device will comprise or include an electromagnetic induction device.

Generally, the electromagnetic induction apparatus in use will be arranged at an angle to the horizontal (typically 40° to 70°) to produce an upward and/or downward driving force against the molten metal. The electromagnetic induction apparatus may be placed in a sloping wall of a chamber in a burner which, in use, contains molten metal. When there is no such inclined wall, the induction apparatus can be placed at an angle on a vertical chamber/furnace wall by means of an attached cradle or port in the flow causing or stirring apparatus.

The cradle or gate preferably comprises an opening which, in use, conveys molten metal material (e.g. in a furnace) and enables e.g. addition of alloy, e.g. silicone into the molten metal material and that samples of the metal can be taken in addition to degassing.

In one embodiment of the invention, the flow causing device or the stirring device is arranged to provide a circulating current in the molten mass, the circulation taking place in a vertical plane so that the fixed scraping material/light additives on top of the molten mass can be pushed downwards and lowered under the influence of the molten metal flow produced by the flow causing apparatus or the stirring apparatus. This produces a more efficient heat distribution, which reduces melting and processing time and also that the scrap material is exposed to an oxidizing atmosphere, and consequently minimizes metal loss through oxidation.

Preferably, the power or speed of the flow causing apparatus or the stirring apparatus will be variable to suit different tasks to be performed by the flow causing/stirring apparatus. If e.g. the flow causing/stirring apparatus is used to drive the flow of molten metal in a downward direction, e.g. to produce a circulation in a vertical plane, the speed can be set higher than if the flow causing/stirring apparatus is used to extract metal from a chamber or furnace. If the speed is set too high when extracting metal from the chamber or furnace, the metal may splash out and cause injury.

Preferably, the flow inducing device or stirring device can be set to different values up to 50 Kz (+/-10 Hz).

Preferably, the flow inducing/stirring apparatus is bidirectional to effect flow of molten metal selectively in two opposite directions, at the operator's option.

In one embodiment and when the flow-inducing/agitating device is bi-directional and is used in one direction to produce circulation in a vertical plane for submersion and mixing of light scraping material/light additives into the melt, the flow-inducing/agitating device can be used in the other direction for to reverse the flow circulation and thus extract molten material from a chamber or furnace.

According to the invention, there is further provided a method for treating molten metal or recycling scrap metal, the method comprising effecting an upward and/or downward flow of molten metal and/or circulation of molten metal in a vertical plane, preferably by an electromagnetic induction device.

Furthermore, according to the invention, the use of an electromagnetic induction device is provided to effect a downward/upward flow of the molten metal material in a vertical plane, e.g. in an oven. Furthermore, according to the invention, in a furnace or a chamber containing a molten metal, it is connected to an electromagnetic induction device at an oblique angle to the horizontal to cause a flow of molten metal downwards and/or upwards and/or a circulation in a vertical plane.

Furthermore, according to the invention, there is provided an electromagnetic induction device which is adapted or arranged to effect a rapid current in molten metal

> 1 Hz, e.g. 50 Hz (+/- 15 Hz).

Other advantages and features according to the invention will be apparent from the following description and the drawings. The invention will now be described in more detail in the following with reference to the drawings, where: Figure 1 shows a perspective view of a flow causing, or stirring device for regulating the flow of molten metal materials, attached to a wall such as, for example. can be a furnace wall; Figure 2 shows a vertical section of the flow inducing or stirring apparatus and chamber/furnace wall shown in Figure 1, along the line II-II, as shown in Figure 1; Figure 3 is a vertical view, partially in section, through a furnace, molten metal material and a flow causing/stirring apparatus as shown in Figures 1 and 2; Figure 4 shows a partial cross-sectional view of a second embodiment of a furnace provided with another embodiment of a flow-inducing/stirring apparatus operating in a direction to effect circulation of molten metal material in a vertical plane; Figure 5 shows a view similar to Figure 4, but where the flow causing/stirring apparatus operates in the opposite direction to extract molten metal from the furnace; Figures 6 and 7 show plan and side views of typical circulation flow patterns set up by the flow causing/agitating apparatus of Figure 4; Figure 8 shows a sectional view of a third embodiment of an oven according to the invention; Figure 9 schematically shows the flow of molten metal in the furnace of Figure 8; figure 10 shows a sectional view of another embodiment of an oven according to the invention; figure 11 shows a sectional view of an oven in figure 2, along the line A-A, and figure 12 shows a sectional view of an oven along the line B-B in figure 10.

In Figures 1-3 of the drawings, the flow-causing or stirring apparatus 500 comprises an electromagnetic induction apparatus in the form of a generally rectangular box 501 connected to an inclined end wall 502 of a cradle or gate 503 in the apparatus 500, of a generally right-angled, isosceles triangular cross-section. The inclined wall 502 has an angle of 45° in relation to the vertical wall 504 and horizontal wall 505 of the cradle or carrier 503.

The manner in which the cradle or gate 503 can be connected to the vertical end wall 600 of the furnace 601 will be apparent from figure 3 of the drawings. The gate or cradle 503 may be attached to the wall 600 of the furnace 601 by creating an opening 602 of suitable size and using a refractor technique to attach the gate in the opening.

The electromagnetic induction apparatus 501 is connected to the end wall 502 in a suitable manner and operates through a thin metal carbide plate 506 (see figure 2), the metal plate construction 506 being made of separate plates.

The gate or cradle 503 has an upper, rectangular opening 507 which, in use, leads directly into the upper surface of the molten metal material M in the bottom of the furnace 601 and which extends into the gate or cradle 503, close to the electromagnetic induction apparatus 501, but on an opposite side of the thin plate 506, as can be seen from figure 3.

In use, and as shown in particular in Figure 3 of the drawings, the electromagnetic induction device 501 (which is in practice a linear motor) can be driven to cause a circulating current in the molten metal. This circulating motion, shown by the arrows in Figure 3, is set up by the downward sloping magnetic driving force (shown by arrow A in Figure 3), produced by the flow-inducing/stirring device 501. The magnetic driving force (arrow A) is a strong current directed substantially axially in relation to the electromagnetic induction device 501 and thus at an angle of generally 45°, parallel to the end wall 502 of the cradle or gate 503.

While the end wall 502 in the previous embodiment is set at an angle of 45°, it is possible to select an alternative angle (eg 30° or 60°) to suit the particular application, or use of the electromagnetic induction apparatus.

It is envisaged that the electromagnetic induction device 501 will be a powerful variable speed motor, e.g. up to 50 Hz. Thus, in use, the electromagnetic induction apparatus 501 will be able to stir the molten metal material M at a very rapid flow rate in the vertical plane. The flow circulation set up in the molten material M is advantageous for several reasons. First, metal materials, (eg scrap metal and/or additives) in the furnace on top of the molten material M will almost immediately, or very quickly, be drawn down and immersed in the material, however lightly. Since such materials are quickly lowered into the molten material M, the disadvantages of oxidizing this are avoided in contrast to the known furnace where light materials can remain floating on the molten material.

Secondly, the circulation flow in the molten material M will be much faster than with known stirring techniques which take place in a horizontal plane. Such stirring techniques typically stir the molten material M at about 1 Hz. The induction apparatus 501 is able to stir the molten metal material at a much higher rate since it sets up a downward current at one end of the molten metal material, rather than acting generally from below over the entire height of the molten material, which requires a very deep magnetic field.

In addition, and preferably, alloying additions, e.g. silicone is discharged through the opening 507 through the port 503 into the molten metal material M and quickly dissolves in the solution. Port 503 can be used as a point to introduce flux and good mixing throughout the molten material.

In addition and preferably, the opening 507 in the port 503 can be used to take samples of the molten material and thus avoid the need to open the main door of the furnace to take the sample.

In addition, the flow causing/agitator 500 can be used not only to circulate the molten metal material M in a vertical plane, but also to degas the boiler 601. A gas lance (not shown) can be introduced into the molten metal stream through the opening 507 to provide a good dispersion in the molten metal M around the base of the furnace.

Since the electromagnetic field from the electromagnetic induction apparatus can be selectively varied, the circulation of the molten metal material or the stirring in a vertical plane can be set up at a regulated rate to suit different materials and/or conditions. The molten metal material M can be stirred at a controlled rate of up to about 15T/minute. Preferably, the introduction of high stirring rates results in an increased melting rate and a greatly reduced temperature and reduced alloy stratification. Low running metal levels can be handled.

While the electromagnetic induction apparatus 501, as described, has been arranged to provide or effect a generally downward flow of molten metal material, (as shown by arrow A) thereby introducing a circulation of molten metal material in a vertical plane, it is contemplated that the device 501 can be bidirectional. If necessary, e.g. the device 501 is arranged to move the molten metal material generally upwards in a direction opposite to the arrow A. Such a possibility can e.g. is used to extract molten metal material M from the furnace in a manner as described below.

Figures 4 and 5 show a second embodiment of a flow causing or stirring device 500' which consists of the electromagnetic induction device 501 placed on an existing, or a specially made inclined wall 700 of a furnace 701. In this case there will therefore be no cradle or gate 503 to connect the electromagnetic induction apparatus 501 to the furnace wall at an oblique angle to effect a downward and/or upward flow or circulation in a vertical plane.

As shown in Figure 4, the electromagnetic induction device 501 may be set to move the molten metal material M in a downward direction to cause a circulating movement of the molten material M in a vertical plane throughout the melting process. When it is desired to extract the molten metal material from the furnace, the electromagnetic induction device 501 can be set to drive the molten metal material in an opposite upward direction, as shown in Figure 5, for transfer out of the furnace along the extraction channel 702, in a manner that will can be seen in figures 4 and 5. It is possible that the electromagnetic induction device 501 and the extraction channel 702 can be constructed together as a unit that constitutes the flow inducing or stirring device, the unit being adapted for connection to an existing vertical side wall of a furnace.

Figures 6 and 7 show typical flow patterns that may occur in the molten material M of the electromagnetic induction apparatus 501 operating as shown in Figure 4.

Naturally, it is possible to supply a furnace with more than one electromagnetic induction device 501, e.g. the electromagnetic induction device 501 and the gate 503 connected at one end of the furnace 601, as shown in Figure 3, to stir the molten material in the furnace and a second electromagnetic induction device 501 provided at an opposite end of the furnace to extract the molten material along the channel 702, in particular as shown in Figure 5. When two such electromagnetic induction devices 501 are provided, they can further be arranged to work together.

When the electromagnetic induction apparatus 501 is used to extract molten metal material from the molten mass M through the extraction channel 702, it will normally be operated at a much lower speed so that the material is not splashed or thrown forward uncontrollably from the channel 702, which would naturally be dangerous to an operator. .

It will therefore appear that the electromagnetic induction device 501 can be set up to effect a movement or flow of molten metal material in a vertical plane by arranging this at an angle to the vertical. When the chamber wall or furnace wall is vertical, the flow causing or agitator may require a gate or cradle attached. If the chamber or furnace already has a suitable inclined wall or a specially prepared inclined wall, the electromagnetic induction apparatus can be attached thereto without the gate or cradle.

Thus, the electromagnetic induction device 501 can be mounted to most surfaces and used on round furnaces as well as on side furnaces for circulation and metal immersion. It can also be attached to static or tilting ovens.

Another advantage is the flexibility that the system of transferring or moving molten metal using the electromagnetic induction apparatus according to the invention provides. Since the electromagnetic induction apparatus is sufficiently powerful to pump upwards, there is no need for a static melter at a higher level compared to the holder/furnace or casting device.

Preferably, the flow causing or stirring apparatus enables metal to be transferred from the furnace without tipping or tapping of ingots and it can be used during tipping/casting at controlled flow rates to maintain a consistent alloy composition, which is particularly important when the density of the alloying elements is not the same as the molten metal material (e.g. aluminum).

In general, the flow causing or agitator 500 will lead to increased production, lower energy consumption and loss of molten mass, molten metal transfer, rapid immersion of light/medium heavy scrap material in the molten metal material, alloy and temperature homogeneity during stopping and faster dissolution of alloys. Preferably, no moving parts are required, which provides little maintenance in addition to the effector or stirring apparatus being suitable for installation on static or tilting ovens.

In particular, the flow causing or stirring apparatus can be used in a sidewell furnace (see Figure 10-12). The furnace 100 comprises a main chamber 112 and a side well chamber 113. Electromagnetic induction device 114 (see figure 12) is used to move the molten material close to the induction device 114 below to thereby produce a circulating movement in a vertical plane. However, the downward propelling motion of the molten material will also propel the molten material in a generally horizontal, circulating direction via passage 172 and return passage 170.

Thus, the powerful driving action of the flow-causing agitator 114 can quickly circulate the molten metal material between the main chamber 112 and the side chamber 113 due to the initial downward traction force exerted on the molten material adjacent thereto. Further description of the invention in relation to a side well furnace is described later in this specification.

Figure 8 shows a single chamber furnace 10 of generally known form with a chamber 12 and a known heat source in the form of a burner 16. The chamber 12 has a floor 18 which comprises a front sloping part 20, a horizontal part 22 and a rear sloping part 24. The front inclined part 20 and the horizontal part 22 form a front area 26 and the rear inclined part 24 forms a rear area 28 of the chamber 12. Electromagnetic induction device 14 is placed according to the embodiment of the invention, on the inclined wall part 20.

The chamber 12 is enclosed, e.g. of walls 30 with a liftable door 32 placed in one of the walls 30. The liftable door 32 makes it possible to introduce metal into the chamber 12.

The oven includes extraction device 34 to remove impurities from the chamber. As previously mentioned, the oven itself is of a known type and will thus not be described further in detail.

Supply of a current to the electromagnetic induction device 14 produces a stream of molten metal.

Since the electromagnetic induction device is preferably inclined in relation to the position of the molten material M, the molten metal flow will have both horizontal and vertical components. This is best seen in figure 9, where the arrows D show the current schematically.

In figures 10-12, an alternative embodiment in the form of two chamber furnaces 100 is shown.

Oven 100 is also of a known type and comprises a main chamber 112, a side well chamber 113 and a heat source in the form of double burners 116, the burners being placed to direct heat directly into the main chamber 112.

According to this embodiment of the invention, the oven 100 further comprises electromagnetic induction device 114, placed in an inclined manner, as shown.

The electromagnetic induction device 114 is placed in the side well chamber 113 and the burners are placed in the main chamber 112. This differs from the embodiment in Figure 8, where both the electromagnetic induction device and the burner are placed in the same chamber.

The side well chamber 113 has an internal side wall 185 for the side well, an external side wall 160 for the side well, an end wall 142 which is common in the main chamber and a liftable chamber door 162 for the side well.

The main chamber 112 and the side well chamber 113 are in fluid connection by means of a first passage 170 and a second passage 172 through the inner side walls 144,158 thereof, respectively.

From Figures 10 and 11 it appears that molten metal M essentially covers the chamber floors 118, 148 of the main and side well and is kept in a liquid state by the burners 116. The molten metal in the chambers has a height F between the floors 118, 148 and the surface of the molten metal.

The first passage 170 connects the front area 156 of the main chamber to the front area 126 of the side well chamber and the second passage 172 connects the rear area 128 of the side well chamber to the rear area 154 of the main chamber. The side well chamber is shielded from the heat produced by the burners 116 in the main chamber by the internal side walls 144, 158.

In other embodiments, the side well chamber can be arranged in relation to the main chamber so that the internal side walls do not need to shield the side chamber from the main chamber, e.g. the first 170 and second 172 passage can be longer, to increase the distance between the two chambers and thereby reduce the effect in the side well chamber of the heat produced by the burners in the main chamber.

It will be seen that the induced current in the molten metal produces predictable surface patterns on the molten metal surface and consequently the extraction device can be placed accordingly in the side well chamber to facilitate the effective removal of solid or gaseous contaminants.

As in the embodiment of Figure 8, the supply of a current to the electromagnetic induction device results in a current in the molten metal M.

However, the molten metal flow differs from the embodiment of Figure 8, due to two chamber arrangements being interconnected by passages. The electromagnetic induction device causes a current in the molten metal which in Figure 10 produces a molten metal current as shown by the arrows E.

The molten metal in the main chamber 112 will flow to the side well chamber 113 via the first passage 117 under the influence of the electromagnetic induction device 114 placed in the side well chamber 113. The effect of sucking molten metal from the main chamber to the side well chamber via the first passage will cause molten metal in the side well chamber to be sucked back into the main chamber via the second passage and thus produce a continuous flow of molten metal between the two chambers.

Molten metal produced by melting light and heavy scrap in the side well chamber will be drawn towards the second passage 172 due to the molten metal flow caused by the electromagnetic induction device, and will arrive at the main chamber 112.

It will be seen from Figure 11 that the roof surface 177 in the second passage is below the height H of the molten metal M and that any impurities that are on the surface of the molten metal will not be sucked into the main chamber, and only clean metal can pass through the second passage.

It is important that the height H of the molten metal is regulated to prevent large amounts of contaminants from entering the main chamber 112 from the side well chamber 113. The height can be regulated by introducing more metal into a chamber.

A combination of removing impurities and regulating the height H of the molten metal reduces the possibility of impurities flowing into the main chamber.

It will be apparent that the scope of the invention is not limited by the specific choice of terminology and that a specific expression can be replaced or supplemented by a corresponding or generic expression. E.g. the term "cradle" or "gate" can be replaced by "carrier". Furthermore, it will be clear that the individual features, systems, methods or functions relating to the flow-causing or stirring device, gate or electromagnetic induction device or furnace may be individually patentable. Nouns in the singular can include the plural and vice versa. Alternatively, any range mentioned herein for any parameter or variable shall be taken as a description of any derived sub-range within the range, or of a particular value of a variable, or a parameter arranged in, or at the end of, the range or sub-range.

Furthermore, accordingly, according to the invention, there is provided a furnace comprising a chamber for receiving metal, a heat source for heating the metal to melt it and an electromagnetic induction device for generating current in the molten material with a vertical component.

By arranging the electromagnetic induction device at an angle, the resulting molten metal flow will preferably not be restricted to flow in the horizontal direction, and will lead to a greater distribution of heat through the molten material and consequently a more efficient melting process.

Preferably, the chamber comprises a first area located near the electromagnetic induction device, and light scrap metal introduced in the front area.

Preferably, introduction of light scrap near the electromagnetic device will cause light scrap metal to be drawn downwards and lowered under the influence of the molten metal stream produced by the electromagnetic induction device. This produces a more efficient heat distribution which reduces melting and process time and also prevents the scrap metal from being exposed to an oxidizing atmosphere and consequently minimizes metal loss through oxidation.

Preferably, the single chamber comprises a rear area with an inclined floor and heavy scrap metal is introduced into the rear area.

Preferably, this means that heavy scrap metal can be partly lowered into the rear area, so that the molten metal flow can wash through the heavy scrap metal. The molten metal in contact with the heavy scrap metal increases the temperature in the heavy scrap metal and any irregularities caught in it, e.g. water, will evaporate when the temperature in the scrap metal increases. This reduces the possibility of exposing water trapped in the heavy scrap metal to a limited or direct contact with the molten metal since the rapid evaporation when water comes into contact with the molten metal can be dangerous.

According to another aspect of the invention, there is provided a method of melting metal in a furnace comprising the steps of providing a furnace with a chamber for receiving metal, providing a heat source, providing electromagnetic induction means, introducing metal into the chamber, heating the metal by using the heat source to produce molten metal, supplying a current to the electromagnetic induction device to produce a current in the molten metal with a vertical component.

A potential limitation of furnaces with a chamber is that both the heat source and the resulting impurities from the scrap metal are contained in the same chamber, the presence of impurities reducing the efficiency of the melting process.

Another limitation in furnaces with a single chamber is that the introduction of scrap metal into the same chamber as the heat source can lead to loss of numbers through oxidation.

This can be partly solved by using the above-mentioned solutions, but if the heat source and metal introduction are in the same chamber, the melting process will have a limited level of efficiency.

Thus, according to another aspect of the invention, there is provided a furnace with a first and second chamber for receiving metal, the first chamber comprising a heat source for heating the metal, thereby producing molten metal, the second chamber not having a heat source and electromagnetic induction device is arranged so that it causes molten metal to flow between the first and second chambers.

By using two chambers, the heat source will preferably be isolated from the area where the scrap metal is introduced.

Furthermore, contaminants produced from the scrap metal can be effectively extracted, so that since the heat source is in a separate chamber and consequently the atmosphere becomes cooler.

According to another aspect of the invention, there is provided a method of melting metal in a furnace, comprising the steps of providing a furnace with first and second chambers for receiving metal, providing a heat source, providing electromagnetic induction means, introducing metal into the first chamber, heating the metal with the heat source to produce molten metal in the first chamber, supplying a current to the electromagnetic induction device to produce a current in the molten metal between the first and second chambers.

According to another aspect of the invention, there is provided a method for melting metal in a furnace comprising the steps:

providing a furnace with a chamber for receiving metal,

provide a heat source,

providing an electromagnetic induction device,

provide an area for loading heavy scrap,

melt a quantum of metal in the chamber,

applying power to the electromagnetic induction device to induce current in the molten metal,

direct the flow so that the molten metal contacts but does not submerge the heavy scrap.

Claims (17)

1. Flow inducing apparatus or stirring apparatus (500) adapted for use in recycling or refining scrap material comprising or including electromagnetic induction apparatus (501) adapted to induce upward and/or downward flow of molten metal material (M) and/or circulation of molten metal material ( M) in a vertical plane, and in which the electromagnetic induction apparatus (501) is arranged in use, at an angle to the horizontal to produce an upwardly inclined and/or downwardly inclined driving force on the molten material (M) to drag material introduced on top of the molten metal downwards to be immersed, characterized in that said flow causing device or stirring device (500) is adapted in use, to simultaneously form a horizontal flow of molten metal material from the vertical plane and/or circulation of molten metal in a horizontal plan. 2. Apparatus (500) according to claim 1, wherein the electromagnetic induction apparatus (500) is arranged in use at an angle relative to the horizontal of 30° to 60° +/-5<0> to produce said upward and/or downward driving force on the melting material (M). 3. Apparatus (500) according to claim 2, wherein the electromagnetic induction apparatus (501) is arranged in use at an angle relative to the horizontal of approximately 45°. 4. Apparatus (500) according to one of the preceding claims, wherein the electromagnetic induction apparatus (501) is placed on an inclined wall of a chamber in a furnace (601) which, in use, contains molten metal (M). 5. Apparatus (500) according to one of the preceding claims, where the electromagnetic induction apparatus (501) is placed at an angle on a vertical wall in the chamber/furnace by means of an attached cradle or port (503) in the flow inducing apparatus or stirring apparatus ( 500). 6. Apparatus (500) according to claim 5, wherein the cradle or gate includes an opening (507) which in use leads to molten material (M) and allows materials to be introduced into the molten metal material (M). 7. Apparatus (500) according to claim 5 or 6, where the power, frequency or speed of the electromagnetic apparatus (501) is selectively varied to adapt to different cases carried out with in the flow inducing/stirring apparatus (500). 8. Apparatus (500) according to claim 7, wherein the frequency is preset to different values up to 50 Hz (+/-10 Hz). 9. Apparatus (500) according to one of the preceding claims, wherein the electromagnetic apparatus (500) is bidirectional. 10. Apparatus (500) according to claim 9, wherein the electromagnetic apparatus (500) is adapted for use in a direction to produce circulation in a vertical plane to lower and mix light scrap materials/additives into the melt mass (M), the electromagnetic the means (501) are adapted to be used in another direction to reverse the current circulation and thus extract melt materials (M) from a chamber or furnace (601). 11. Apparatus (500) according to one of the preceding claims, in which the electromagnetic induction means (501) in use act through a thin plate (506). 12. Flow inducing device or stirring device (500) comprising or including selective two-way electromagnetic induction device (501) adapted to induce upward and/or downward flow of molten metal material (M) in tank (601) and/or circulation of molten metal material (M) in a vertical plane, for example a furnace (601) and in which the electromagnetic induction apparatus (501) is arranged in use, at an oblique angle to the horizontal to produce an upward oblique and/or downward oblique driving force on the molten material (M ), characterized in that said flow-causing device or stirring device (500) is adapted to use, and at the same time form a horizontal flow of molten metal material from the vertical plane and/or circulation of molten metal in a horizontal plane, the electromagnetic induction device (501) is adapted for use in one direction to produce circulation in a vertical plane and submerge materials on top of it s the molten metal (M), and adapt in a reversed direction to extract molten material (M) from the tank (601). 13. A furnace or chamber (601) for treating molten metal material (M) in combination with at least one of flow inducing apparatus or stirring apparatus (500) according to one of the preceding claims. 14. Method for recycling or refining scrap materials (M) where the method comprises inducing upward and/or downward flow of molten metal material (M) and/or circulation of molten metal material (M) in a vertical plane, with an electromagnetic induction apparatus (501), characterized by including a horizontal flow of molten metal material and/or circulation of molten metal in a horizontal plane, and including introducing the scrap material into the molten metal (M) and pulling the scrap material downward to become submerged by said upward and/or downward flow of molten metal (M) and/or circulation of molten metal (M) in a vertical plane. 15. Method according to claim 14 including introducing scrap materials through an opening (507) in a cradle or gate (503) of flow inducing agents or stirring agents (500). 16. Method according to one of claims 14 to 15 including operating electromagnetic induction means (501) bidirectionally to suit different tasks. 17. Method according to one of claims 14 to 16 including that electromagnetic induction means operate at up to 50 Hz (+/-10 Hz).