FI108852B - Continuous process for removing a pollutant - Google Patents

Description

108852

Continuous method for removal of impurities - Kontinuerligt arbetande förfarande för avlägsnande av et föroreningsämne

The present invention relates to a continuous process for the removal of an impurity solubilized in metal in a substantially gaseous form using a solid state reactant having a high affinity for said impurity gas and a low affinity and solubility in the molten metal having a substantially lower specific gravity than in a method comprising: providing a molten metal for said refining 10 to a treatment vessel; holding said reactant by a tab means below the surface of the metal melt; and removing the refined metal from said treatment vessel.

One relatively widespread raw material casting process for metal wire, particularly copper wire, is the Upcast, Verticast process, which allows the production of non-oxygen (OF) copper wire by solidifying the metal in a cooled die at the top of the melt and pulling the solidified. This "rod" is brought to its final thickness by tensile forming. High quality copper cathodes that are melted in mesh induction furnaces are: * *: 20 protected by charcoal to prevent oxidation. Charcoal has been used in the past »· ·. ·. in the prior art by feeding them to the molten surface, whereby the charcoal as compared to the copper melt floats lightly without sinking on the molten surface. As a result, the reduction -... effect is small and, moreover, the charcoal on the molten surface is glowing and the atmosphere oxygenated ;; I pi burn them, resulting in unnecessarily high carbon consumption and a reduction in * ·· ** 25 Eastern. The requirements for non-oxygenated copper include very low oxygen content, usually only a few ppm, such as less than 5 ppm or less than 0.0005% 02. Also, low oxygen content in the casting process is good because the oxygen in the molten metal also consumes graphite used as the die material. life.

, ...: Even vertical use has been limited by the relative slowness of the casting, that is to say, · · ·, 30 per annum produces about 1000 tons per year. In addition, the space required for molding nozzles on the surface of molten copper and separate melting and casting furnaces to ensure oxidation, with their melt transfer problems between them, has been a limiting factor. A limiting factor:: The cost of the two furnace units has continued to exist.

JP-63-108946 attempts to solve the above-described problems by using a warm-keeping furnace in which the metal to be refined is molten and from which 2,108,852 is molten for further processing. The reducing agent used is charcoal, which is known per se, but in this warm-keeping furnace, the carbon is pressed deeper into the melt, consisting mainly of a sheet of alumina. In this case, the contact area between the carbon and the metal melt is made larger and thus the reduction is somewhat no-5. According to the publication, the furnace is heated by an electric resistor above the metal melt, the coals and the plate used for their immersion. The sheet of insulating material prevents short-circuiting of the electrical resistor through the reducing agent and / or the metal, thereby preventing possible accidents. The arrangement proposed by the publication still has the disadvantage of the rapid combustion of carbon by the atmosphere. It is impossible to save carbon-10 during the process. In order to add carbon, the process must be interrupted, the carbon-weight plate lifted up and pressed down again after the carbon addition, which makes the proposed process slow and cumbersome. In addition, the rate of reduction itself is still to be desired. JP-5-195104 has tested the effect of carbon immersion on oxygen scavenging efficiency in a crucible. The arrangement of this 15 publications has all the same drawbacks as the procedure proposed in the above-mentioned publication and, moreover, it is purely input-type and is practically unsuitable for production operations.

It is an object of the invention to provide a refining process for the rapid and efficient removal of a substantially gaseous contaminant dissolved in a metal in a solid state. This means that the reduction or oxidation provided by the solid reactant should be made effective in proportion. . '; the amount of metal to be refined in the process. Another object of the invention is:. · To provide such a refining process that can be carried out continuously; which means that it is not necessary to interrupt the process, at least not to add the raffin, ...: 25 metal or solid reactant, but where the metal to be refined is ···. and / or the solid reactant may, however, be added in batches, if necessary.

! '.! A third object of the invention is to provide a refining process in which the consumption of a solid reactant for reasons other than reacting with an impurity is minimized. A fourth object of the invention is to provide a refining process which reduces the consumption of solid reactant by preventing or reducing the re-oxidation or the reduction, respectively.

It is a further object of the invention to provide a refining process which, when used, could be considered to have low or reasonable hardware costs.

The disadvantages described above can be eliminated and the objectives defined above can be achieved; ""; The process is carried out by a continuous method according to the invention, characterized by what is defined in the characterizing part of claim 1.

3, 108852

The advantage of the invention over the prior art is that the invention can significantly improve the removal of oxygen from the metal melt, for example, and at the same time reduce the consumption of a reducing agent such as carbon for useless combustion as well as the leaching of oxygen from the air to the metal melt. In addition, the transfer of the metal-5 melt can be reduced because, according to the invention, metal smelting and / or vertical casting into a rod or wire can, if necessary, be made in the same furnace as the above refining without deteriorating the casting quality. However, the process of the invention can be applied while maintaining the above mentioned advantages even if the metal to be refined is melted in a separate furnace 10 and / or the refined metal melt needs to be further processed, for example doped, in a molten state further and separately from said refining. The method of the invention also provides excellent opportunities for process control and control. A further advantage is that there is more space for the casting nozzles than in the prior art solutions, since it is possible and advantageous to use a thinner flat oven than conventional.

The invention will now be described in detail with reference to the accompanying drawings.

Figure 1 generally depicts a metal melt processing vessel for carrying out first embodiments of the method of the invention, in longitudinal vertical section 20, along plane I-I of Figure 2.

FIG. 2 shows a processing vessel of FIG. 1 for carrying out the method of the invention, viewed from above along the plane II-II of FIG.

I · ·

Figure 3 generally depicts a metal melt processing vessel for carrying out other embodiments of the method according to the invention, in a view similar to that of the figure. 25 received.

• · I · l

Figure 4 generally depicts a metal melt processing vessel for implementing third embodiments of the method of the invention, in a similar view to that of Figures 1 and 3.

Figure 5 generally depicts a metal melt treatment vessel for carrying out fourth embodiments of the method of the invention, in a view similar to that of Figures 1, 3 and 4.

* »» »4 108852

Figure 6 generally depicts a metal melt treatment vessel for implementing fifth embodiments of the method of the invention, in a similar view to Figures 1 and 3-5.

Figure 7 generally shows a metal melt treatment vessel for carrying out sixth embodiments of the method of the invention, in a similar view to that of Figures 1 and 3-6.

Figure 8 generally depicts a metal melt treatment vessel for carrying out seventh embodiments of the method of the invention, in a similar view to Figures 1 and 3-7.

Fig. 9 generally illustrates a metal melt treatment vessel for carrying out eighth embodiments of the method of the invention, in a similar view to Figs. 1 and 3-8.

First, the refining apparatus used to apply the invention will be described. The treatment vessel 1 of the refining metal M1 according to the invention is typically an oven containing an inductor 3 and is most preferably intended for vertical casting. M 1 refers to the metal to be refined, M 2 refers to the refined metal and M refers to the molten metal in general. The treatment vessel 1 is in this case a mesh-frequency trough induction furnace having one or more induction trough 13 opening into the melt chamber, from whose ends the metal melt M flows into the induction trough 13 and from which ends a hot metal melt is introduced into the molten space of the treatment vessel. According to the invention, it is advantageous to place the induction trough 13 in the bottom 24 of the treatment vessel 1 so that the flow P from the trough will hit the layer H2 of the reactant 7, such as an oxidizing or reducing agent, to be treated below. The inductors can be either U, ···, channel inductors or W channel inductors. In the case where the furnace is intended to melt metal bodies in solid state, i.e. solid state 8 in direction S2a, as in the embodiments of Figures 1-3 and 6, according to the invention, it is expedient to use an inductor with the greatest * · * · ·· * thawing power a melting inductor, whereas in the case where the furnace is fed into the furnace in the direction S2b, the molten parent metal M1, as in the embodiment of Figure 4; 30, it is expedient to use an inductor to provide a trough, ·. the highest possible velocity for algae flow P, but with a melting power of • \ low or so-called. sekoitusinduktoria. In a situation similar to the latter case, I t | Thus, according to the invention, the inductor can also be completely omitted and the flow of the metal melt to the reactant layer is generated by the metallostatic pressure of the parent metal, as shown in Figures 7. and 8. Obviously, in the case of molten parent metal M1, both of the above methods can be combined, i.e., flow P can be generated by a mixing inductor from the direction S2c as well as a relatively low power. By utilizing the forthcoming refining metal stream, overheating of the Raffi-5 witch melt M may be avoided if the refining molten metal M1 is already at a sufficiently high temperature. The width W1 of the melting space of the processing vessel 1 is larger and preferably considerably greater than the depth H1 of the melt. Such a design allows e.g. feeding complete or uncut copper cathodes 8 or the like with its flap, i.e., substantially horizontal to furnace 1, such as ku-10, 1, 3 and 6, is indicated as motion directions S2a. The furnace may also be fed with pre-melted metal in the direction S2b or S2c, as shown in Figures 4 and 7-8. Thus, a sufficient number of mixing or defrosting inductors 3 are fixed to the bottom or other suitable point of the furnace, in particular to provide the flux P of the metal melt M in the treatment vessel 1, but also to provide melting power, if necessary. a plurality of molten metal inlet channels 23 to provide flows P of the metal melt M in the treatment vessel 1. In this specification, the term "furnace" refers to a melt processing vessel, whether or not it is subjected to a melting power, so that Figures 7 and 8 also show the furnace. In this context, the small depth of the furnace H1 20 is particularly advantageous, since the melt flow P then effectively hits the "reactant" layer from below, as will be described below.

. : The major part of the surface L of the metal melt M is covered by a deck-like raft part 4 which leaves the molten surface substantially free of the feed area A1 through which, for example, copper: *: the dips sink in S2a or the metal melt is fed upstream: ··· at the other end, the necessary casting area A2, for example for casting nozzles 5a for vertical casting in the upward direction SI, or * 4 ·, · · ·. for melt discharge means 5b, for example, for downward flow S3. In the case of pre-molten metal M1 being fed into the furnace, as a stream M 2 in the direction S2c towards the reactant layer 7 from or through the region of the furnace bottom 24 or end wall 25, the feed area A1 may be very small such as: is specifically shown in Fig. 8. The metal to be cast and discharged is in the treatment vessel 1 the refined metal M2. The longitudinal edges of the ferry section connecting. the ends of the platform 4 defining said feed area A1 and the casting area A2 are possible close to the longitudinal side walls 26 of the furnace, but normally with a small clearance 18. The casting nozzles 5a as well as the discharge or pouring opening 5b can be any suitable type, so they are not described in more detail. In the free zones, the surface L of the metal melt M is shielded from the ambient atmosphere by, for example, a layer H2 of graphite powder, graphite flakes 2 or coating salts. The raft 4 may, for example, consist of a steel back plate with an insulating layer and refractory masonry attached, i.e. the raft has at least 5 lower refractory materials. Other types of raft construction can be used. At least some, usually at least three, and possibly all edges of the lower surface of the board 4 are provided with downwardly facing ridges 11, the meaning of which will be discussed later. The height of the ridges 11 from the lower surface 14 of the board 4 is at least equal to any predetermined thickness H2 of the reactant layer.

In the continuous process of the invention, the impurity dissolved in the metal in substantially gaseous form is removed by using a solid state reactant having, firstly, a high affinity for said impurity gas and a minimal affinity and solubility for the molten metal. Such impurity may be at least oxygen, but possibly also hydrogen in some cases. The solid reactant 7 in the solid state may be carbon, for example in the form of charcoal or the like, in the case of a reducing agent. When the impurity gas is hydrogen or another type of gas, the solid reactant should be an oxidant. Second, the specific gravity of the light reactant is substantially lower than the specific gravity of said metal to be refined in the molten state, whereby the reactant is not immersed in the metal melt, but its behavior in the process can be adjusted, as'! explained below. To refine the parent metal M1, it is arranged in a molten M

• either inside or outside the handling container. In addition, the re-; actant 7, which preferably consists of pieces of suitable size, with a tile means::: ·: 25 below the surface of the metal melt and after refining, the refined metal is removed from said treatment vessel in any suitable manner, as already mentioned.

According to one embodiment of the invention, first, currents P of at least the metal melt are generated in said molten metal M by electromagnetic induction produced by the aforementioned inductors 3 and their induction. * 30 with troughs 13. According to another embodiment of the invention, said mouth,, ·. plating metal M at least metal melt flows P in advance molten parent metal

M1 with the inlet flow from the inlet channel 23 or the inlet passages 23 which are obtained: by the aforementioned metallostatic pressure of the parent metal. When the inlet duct 23 is surrounded by a closed wall 30 above the surface L 35 of the metal melt in the furnace 1 at a height H5 and the inlet duct 23 opens through the furnace bottom 24 or end wall 25 into the melt space, it is understood that the inlet duct discharges. The intensity of the flow P can be obtained by designing the height H5 and the cross-sectional area (s) of the inlet (s) to be predetermined and possibly adjustable. If the relatively low flow P is sufficient, it can also be achieved by the overhead flow S2b alone, as indicated by the reference F in the flow 5 P in Figure 4, in which case the inductor 3 must be considered removed from the furnace. These metal melt flows P are allowed to exert on the 7 layers of light reactant 7 below the plate 4. When the distance H1 between the surface L and the bottom of the molten metal melt is suitably small, of course relative to the power of the inductor and / or the velocity of the input stream S2c or S2b, at least relatively strong currents are obtained. light reactant between pieces. This substantially enhances the reaction between the light-reactant 7 layers of H2 and the metal melt M.

| The inductors 3 can be used solely for the above-described mixing of the metal melt and the light reactant, whereby the metal to be refined M1 is melted elsewhere and introduced into the treatment vessel 1, as shown in Figure 4, either continuously or intermittently. Alternatively, and preferably, the metal M1 to be refined is melted in the treatment vessel 1 using these inductors, as shown in Figures 1, 3, 5 and 6, in which case the metal to be refined M1 is added to the furnace in solid or solid state. In the 20 cases where the metal M1 is added to the treatment vessel 1 in solid state, i.e. metal bodies 8, it is preferable to count these as yet unmelted bodies as such. 3 within the furnace 1 that the heated metal melt flow P from the induction chute will hit or target these metal bodies, as shown in Figure 3: 1. In this case, the application of the melt flow P to the light reactant 7 times; · ·· 25 rust H2 slightly or for some time disturbance, but it is not essential because the metal body or bodies 8 melt very quickly and most of the metal melt flow from the inductor to the light reactant layer on the underside of ferry 4. When the metal M1 to be refined is melted by applying a melt flow P from the inductor thereto, it is further obtained ;;; The advantage is that the melt flow P - which is directed to the light reactant layer - carries the molten metal to be refined with the light reactant 7 to H2, whereby the impurity therein reacts with the light reactant and diffuses to the other parts of the treatment vessel only thereafter. Therefore, raffi-! t »'. the process is very fast and the effect of unrefined melting metal is conceptualized. By substantially increasing the concentration of the impurity M of the metal melt in the lye 1, 35 can be substantially eliminated. Further, the reaction between the light reactant 7 and the metal melt can be enhanced by increasing the thickness of the reactant layer H2 below the surface L of the metal melt 10 8 88852 M as described below. The foregoing also applies, mutatis mutandis, to the effects of a melt flow fed through the end or bottom 24 of the treatment vessel.

Further, according to the invention, this treatment vessel 1 itself uses at least 5 relatively tight raft 4, the lower surface 14 of which is held at a predetermined constant or variable and adjustable height ± H 3 relative to the surface of the metal melt. Thus, the lower surface 14 of the board may be below the molten surface L [= -H3] or above the molten surface [= + H3]. This height is less than the thickness H2 of the reactant layer on the molten surface, which results in reactant 7 being contained within the melt. There is no need for the rig to be at optimum height and light reactant depth at all times in the molten metal M. When raft 4 is substantially gas-tight in structure and has ridges 11 extending below molten surface L at all edges, positioning of lower ramp 14 above molten surface however, surface contact with the surrounding atmosphere is prevented. Due to the possible supply channels of the reactant 7, due to the devices providing them of sufficient length and / or the force F of the reactant, at least no significant amounts of the harmful atmosphere surrounding the gas are released. Thus, the board 4 prevents contact of the major part of the surface of the metal melt M with the surrounding atmosphere. The mild reactant then reacts with the impurity gas 20 dissolved in the molten metal and the reaction result, which is typically a gas insoluble in the molten metal, is removed | ^ molten metal so that it is refined to a predetermined impurity gas! i concentration.

* * * ·> ·; V; Still according to the invention, the light reactant 7 can be fed below the board at such a rate that at least part of the thickness of the reactant layer extends below the surface of the metal melt. This feeding of the light reactant is effected by pressing I · *; The outer force F can be advantageously exerted through one of the supply channels 6a or more of the supply channels 6a in the region of the raft 4, which extend from the top of the raft to the surface of the molten metal. 1, 3 and 6.

* · '..: 30 At the upper ends of the supply channels 6a there is provided an apparatus, such as a piston mechanism or «, supply screw, to obtain said force F. As such feeding devices 16a, any suitable mechanism or means which is not so described can be used. Alternatively, the external force F and the path of the light reactant may be exerted by a supply channel 6b arranged below the platform area and extending through the bottom of the processing vessel 1, with a suitable valve arrangement 16b provided thereto. Opening the valve discharges a batch of light reactant into the metal plate, thereby raising it against the lower surface 14 of the plate. The valve assembly may also be of any type suitable for the purpose, and thus not further described. However, this should only apply to metals with a relatively low melting point. Alternatively, the external force F and the light reactant path may be implemented below the edge of the raft 5 by using an automatically or manually actuated arm end clock 16c which is pressed beneath the molten surface, e.g. the light reactant is disposed of, so that it rises against the lower surface 14 of the raft.

By feeding the board 4 and the light reactant 7 by force F, the reactant 10 is forced into the molten, whereby their reaction effect is substantially stronger than in previously known furnaces where light charcoal floats on the molten surface, whereby the carbon is wasted and the ash The light reactant pieces beneath the ferrule section 4 are protected so that ambient air does not come into contact with them, so that, for example, the coals do not burn unnecessarily. As a result, coal consumption and slag formation are substantially reduced compared to prior art, thereby saving both coal acquisition costs and operating costs. The low or higher ridges 11 on the lower surface of the platform portion prevent the charcoal pieces from sliding between the edge of the platform portion 6 or the bottom 11 of the ridge 11 between the ferry portion and the oven walls.

. . The metal to be refined M1 is fed to the metal already in said processing vessel 1; molten in the feed region A1 of the first end of the vessel in either solid direction S2a or ♦ · • '· melt in direction S2b or S2c. Casting of refined molten M2 to a solid state and; upstream S1 through the aforementioned casting nozzles 5a, or downwardly flowing S3 of refined molten M2 25 through nozzle 5b, or horizontally, in a manner not shown in the figures, to the further treatment vessel at the opposite end of the furnace A2. Thus, in the process, the refined molten metal can preferably be cast into a tank or tube in a continuous vertical casting upwards, using one or more of these. ···. a die 5a embedded in a metal melt in a treated treatment vessel. The process is easily made continuous, since the light reactant 7 can be added continuously or intermittently below the plate 4, as described in the preceding paragraph, without having to interrupt the process. As a continuous process, further refining metal and / or light reactant is fed to the processing vessel either periodically or continuously so that at least a small amount of both is always present in the process so that no interruptions occur. Likewise, casting into a tube or rod or draining from the nozzles 5a, 5b can be completely continuous or intermittent.

The rig 4 in the treatment vessel 1 is thus prevented from contacting the major part of the metal-molten surface L with the surrounding atmosphere, as described above. According to yet another aspect of the invention, the treatment vessel further prevents substantial contact of the remainder of the metal melt M surface, i.e. the feed area A1 and the casting area A2, and the surface L of the metal melt 5 with recesses 18 with the surrounding atmosphere by providing a layer of graphite powder or graphite flakes or Graphite is more advantageous because it does not melt but forms a dense layer on the metal melt, which prevents both harmful gases from entering the surrounding atmosphere from the metal salt and reduces heat loss from the furnace 1. Further, the graphite layer 20 can easily push casting nozzles 5a and feed M1 in directions S2a and S2b. Similarly, in any further treatment vessel 29, substantial contact of the metal molten surface with the surrounding atmosphere is prevented by providing a layer of graphite powder or graphite flakes or coating salts 20 on the molten surface.

When the reaction product of the light reactant and the impurity gas in the metal to be refined is gaseous, it is also allowed to exit through the light reactant feed channel (s) 6a, so that no harmful gases are discharged in the opposite direction. In the feed area A1 and the flow area A2, the gaseous reaction products exit without problems through the layer 20 of graphite powder or graphite flakes.

20 Depending on the need, samples of the melt can be taken, analyzed and the inductor 3 made. . power, rate of addition of refined metal M1, removal of refined metal M2; and / or light reactant 7 addition rate decisions, either manually or automatically. According to a further aspect of the invention, the composition of the gasses exiting the dish: light reactant addition channel 6a is analyzed, such as gaseous impurity dissolved in gaseous form and light reactant | the reaction product, for example its concentration and / or quantity in the measuring device 19, and draw from it the above or equivalent conclusions. Alternatively, the above-mentioned off-gases and the said reaction product may be analyzed by measuring ···. by means of device 19 also using a separate pipe directly under the bottom surface of the raft, ···. 30, as shown in dotted lines in Figure 6. The method of the invention

allows predetermined corrections to be made to the process, based on various measurements, to maintain the concentration of said impurity in the metal melt below or within predetermined: limit values. The adjustment can be accomplished by changing the surface L of the metal melt M

, · · · '35, that is, the amount of submerged light reactant 7 and the distance S between the light reactant layer H2 and the induction openings 13 of the inductors 3.

108852 11

The thicker the thickness of the reactant layer H2 under the molten surface, the more effective the reaction and the smaller the distance S between the mouths of the induction chutes and the light reactant, the more effective the reaction. If the thickness of the reactant layer H2 remains approximately constant during the observation period but the raft is downward, the distance S decreases. If initially the raft bottom was above the molten surface [situation + H3], the molten surface in the reactant layer rises, i.e. grow. Both changes work in the same direction, making the process more efficient. This is a relatively quick adjustment. Of course, light reactant 7 can be added by keeping the lower surface 14 of the plate at a constant height, whereby the thickness of the reactant 10 layer H2 increases and is more below the molten surface L. However, this is a slower way of reacting, so the former adjustment of the height of the raft is the actual control variable, which is excellent because the variables work in the same direction, allowing the control to easily converge towards the target value. Obviously, if a reduction in the reaction rate is required, the opposite is true of those described above. Thus, the concentration of said impurity gas in the metal melt is kept below a predetermined limit value or between the desired limit values.

It is advantageous to carry out the process according to the invention when the metal to be refined is M1 electrolytic copper, in particular electrolytically produced copper cathodes, wherein the gaseous impurity is oxygen. In this case, said light reactant 7 is carbon, especially charcoal. The process according to the invention can also be applied when the refining metal M1 is a copper alloy, silver, aluminum. : or magnesium. In particular, when said copper cathodes are used as starting material, they: v. is fed in the direction S2a to the induction furnace in the feed region A1 mainly by its flap, ''. 25, as can be seen in the figures, after which they are allowed to melt in the strong melt flow P from the inductor 3 · · ...

Since the vertical casting process is a continuous operation, the raft portion 4 may be fixedly connected to the edges of the furnace, such as the ridge portion 4 forming the lid 4 'in Figure 9, with the height of the molten surface determined by cathode feed or molten refining. 30 stables feed rate and casting rate, as well as overpressure or '·' under pressure under the deck. However, the elevated ferry section 4 provides more degrees of freedom. For example, the ferrule section may be floating or passively suspended from the brackets at suitable weights or the like at a predetermined depth on the surface of the metal melt M. . : image structure or suitable machine elements known per se for different heights, ·> ·. 35 Depth or Variable Depth Adjustment, with adjusting actuators • between the treatment vessel or surrounding structures and the raft to a predetermined or 12 108852 variable height relative to the surface of the metal melt. The lower surface 14 of the board 4 may be held at the height of the metal melt surface, as in Figures 1 and 4, or below the surface, as in Figure 3, or above the surface, as in Figure 5. The preferred means for adjusting the height Δρ compared to the ambient atmosphere, whereby first, the gaseous reaction product of the impurity in the metal to be refined and the light reactant is removed more efficiently from underneath the raft and secondly, the vacuum draws the gas-tight raft 4 deeper into the metal melt. Thus, the previously described adjustment can be realized with this vacuum. A further advantage of this negative pressure -Δρ is that it also contributes to the removal of other gases such as hydrogen from the molten metal M.

To remove gases from molten material such as aluminum and magnesium, but also copper, a higher vacuum may be used if the plunger in position + H3 is prevented from being partially or partially pressurized by forming the plate 4, for example the previously mentioned lid 4 ' the height + H3 between the ridges 11 at the edges, or the height + H3 between the lower surface 14 of the lid and the molten free surface L in contact with the ambient pressure, respectively. In this case, the molten surface L * defined by the ridges 11 of the bottom surface 14 of the board rises, under reduced pressure 20, to a significantly higher level of the board surrounding the free molten surface L or the original molten surface L in the treatment vessel. : from the molten surface L as shown in Figures 5 and 9. For degassing . ·. : depending on the molten metal, the surface of the molten surface can be raised, for example, by a different amount of 10; / centimeters to easily achieve a negative pressure of -Δρ of about 20 to 30 '25 kPa, which is usually sufficient for degassing. Alternatively, overpressure + Δρ may be provided under the plate 4 or the lid 4 ', [.,' Attached to the treatment vessel 1 by introducing ··· 'from there an additional suitable gas or air, whereby the molten surface L ** of reactant,' * 1, \ ... · In 7 layers, calculates the distance -H4 relative to the original or surrounding salt surface L. When using the cover 4 ', it is not necessary to use on a molten surface: [: 30 graphite powder, graphite flakes or coating.

The amount of vacuum under the platform can also be varied, either vacuum. .: Δ [-Δρ] side or overpressure Δ [+ Δρ] or under vacuum to overpressure Δ [-Δρ * ... · -> + Δρ] and back to Δ [+ Δρ -> -Δρ], generally the change in pressure Δ [ Δρ]. This gear causes the molten flow P within the reactant layer and greatly enhances the process 35.

13 108852

The lower surface area delimited by the ridges 11 of the lower surface 14 of the board 4 can be subdivided by placing additional ridges 11 'at suitable locations on the lower surface, as shown in Figure 5. The resulting pressures -Δρ and -Δρ' can be independently adjusted and altered by gas channels.

With reference to Figures 7 and 8, it should be noted that the inlet channel (s) may extend over the entire width W1 of the furnace, but it is more advantageous to confine them in this direction to form only a portion of the furnace width W1, a plurality of parallel or otherwise tracked widths of the furnace in its feed area A1, just as the outlet channels or nozzles 5a and / or 5b are in the furnace casting area A2.

• »1 i i

Claims (18)

A continuous process for removing a gaseous pollutant substantially dissolved in a metal by means of a solid-state reactant (7) having a high affinity relative to said pollutant gas and a low affinity and solubility in said metal. molten metal (M) as possible and the specific weight of the light reactant is substantially lower than the specific weight of the metal to be refined in molten form, in which process: - melting of said metal (M1) to be refined in a treatment lingual vessels (1); 10. said reactant is held with a disk tool below the surface of the molten metal; and - refined metal (M2) is removed from said treatment vessel, characterized in that the process further comprises the following phases: - in said molten metal, streams (P) are generated in at least the metal melt; 15. as said disk tool, a raft (4,4 ') is used which is poured at a predetermined or at an adjustable height (± H3) relative to the surface of the metal melt (L, L *, L **) in this treatment vessel, which height is less than the thickness (H2) of the reactant layer present on the surface of the melt; - said light reactant (7) is measured under said raft at such a rate that at least part of the thickness of the reactant layer extends below the surface of the metal melt (L, L *, L **); and - the light reactant was allowed to react with pollutant gas which has dissolved in the molten ·. *. the metal and the reaction product emit from the molten metal for refining to a pre-defined haze of pollutant gas. 2. A continuous process according to claim 1, characterized in that in * ': said fluxes (P) in the metal melt in the molten metal in the treatment vessel:' '. are generated by electromagnetic induction and / or metallostatic pressure. 1 · * t Continuous process according to claim 1 or 2, characterized by. the process further comprises the following phases: «· · · 30. refined molten metal is cast into a rod or tube in the form of continuous vertical casting (5a) by means of one or more nozzles, which are lowered from above. : lowered in the metal melt in said treatment vessel; and: - more metal (M1) to be refined measured in said induction furnace. Continuous method according to claim 1 or 2, characterized in that the process further comprises the following phases: refined molten metal was allowed to flow (5b) from said treatment vessel to a vessel for further treatment of metal; in the vessel for further processing, the surface of the metal melt is substantially prevented from coming into contact with the surrounding atmosphere by providing a layer of graphite powder or graphite flakes or salts for blackening (20) on the surface of the melt; and - more metal to be refined is measured into said treatment vessel. Continuous process according to any of claims 3-4, characterized in that in the process further: - addition of metal to be refined and light reactant in the treatment vessel is continued either continuously or for periods; and - the flow of refined metal into the vessel for continued processing or vertical casting of the same continues either continuously or for periods. 6. A continuous process according to any one of claims 1 to 5, characterized in that the method further permits said electromagnetic induction to melt solidified metal to be refined. Continuous process according to any of claims 1-6, characterized in that the process prevents contact in the treatment vessel with said raft (4, 4 ') between the main part of the metal melt surface with the surrounding atmosphere. A continuous process according to claim 1 or 2 or 7, characterized in that in the process the light reactant is pressed by the action of an external; : force (F) into the surface of the metal melt against the metallostatic pressure of the melt either •,: through a channel or channels (6a) in the area of the fleet or alternatively under the fleet! . ] edge (6c) or through a channel or channels (6b) in the bottom of said treatment vessel. 9. Continuous process according to claim 7 or 8, characterized in that: "where the reaction product of the light reactant and the pollutant gas to be refined is gaseous, it is allowed to remove by one in ....: the raft located additional channel (s) (6a) for the light reactant. . Continuous process according to claim 1 or 2 or 9, characterized in that further in the process in phases: ....: - the melt is analyzed, or said gaseous reaction product which is removed through the auxiliary duct for light reactant in the raft, or otherwise: • a pre-definition; and '*' - on the basis of some / some of them, the lowering depth of the light reactant and / or the height of the surface of the melt in the reactant layer is changed so that the content of said contaminant gas in the metal melt remains below a predetermined limit value or between predetermined limit values. 11. A continuous process according to any of claims 3-5, characterized in that the metal to be refined is fed into the metal melt already present in said treatment vessel in the feed area (AI) at the first end of the furnace and the casting or flow of the refined the melt to the vessel for further treatment takes place in the outlet area (A2) at the opposite other end of the oven. Continuous process according to claim 1 or 2 or 6, characterized in that said flows (P) in the metal melt are allowed to align with the layer of light reactant under the raft; and that the currents are arranged to their strength so that they give rise to relative movement in the light reactant pieces and currents of the melt between the light reactant pieces. Continuous process according to claim 1 or 2 or 7 or 12, characterized in that under said raft, a negative pressure (-Δρ) is obtained in relation to the ambient atmospheric pressure. Continuous process according to Claim 1 or 13, characterized in that a variable pressure (Δ [Δρ]) is produced under said raft for effecting flow (P) of the melt in the reactant layer. A continuous process according to claim 1 or 2 or 6 or 12; ; characterized in that said currents (P) in the metal melt are generated by an inductor; ': gutter in the induction furnace; and that the heated metal melt coming from the induction trough was allowed to focus on the still-unmelted metal added in the oven to be refined. Continuous method according to claim 1 or 2 or 7, characterized in that contact is prevented between the surface areas of the metal melt contained in the treatment vessel, which is in the gap between the side edges of the fleet and the sides of the treatment vessel and also at the feeding area and the casting area. and ··· * the surrounding atmosphere by covering said areas with a layer of graphite •: ·: 30 powder or graphite flakes or salts for blackening (20). Continuous process according to any of the preceding claims, characterized in that, as said metal to be refined, electrolyte copper pairs, especially electrolytically produced copper cathodes, are used; and that said light reactant is koi, especially charcoal. Continuous method according to claim 17, characterized in that said copper cathodes are fed into the induction furnace in the feeding area mainly on the side. • · • · 1 I · • t * · * · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · • t · •• Il • ·