KR101997348B1 - Method and apparatus for refining metal - Google Patents

Abstract

The present invention relates to a metal refining method and apparatus, comprising the steps of: preparing a molten metal containing an impurity element and a molten metal containing slag floating on the molten metal; Contacting the cathode with the molten metal and contacting the anode with the slag to define a refining zone between the cathode and the anode; Moving the impurity element in the refining zone at an interface between the molten metal and the slag; Applying a first electric power between the anode and the cathode to ionize the impurity element moved to the interface; And removing the ionized impurity element by moving the impurity element ionized by the second power applied between the anode and the cathode to the anode through the slag.

Description

[0001] METHOD AND APPARATUS FOR REFINING METAL [0002]

TECHNICAL FIELD The present invention relates to a metal smelting technique, and more particularly, to a metal smelting method and apparatus.

The alloy element dissolved in the molten metal during the melt reduction or refining process reacts with the impurity element such as dissolved oxygen (O), sulfur (S), carbon (C), nitrogen (N) and phosphorus (P) inclusion may be generated, which may cause problems of degrading the quality of the metal alloy through growth and segregation during the solidification process of the molten metal. Removal of the nonmetallic inclusions generated in the melting and reducing and refining processes of such metals can generally be accomplished through slag refining.

However, the slag refining method is accompanied by stirring to increase the mass transfer. In addition to the mixing of the slag with the molten metal by the stirring, the increase in the manufacturing cost due to the energy loss due to the temperature lowering of the molten metal ≪ / RTI > In addition, a certain level of dissolved oxygen exists in the molten steel subjected to the slag refining process, and in particular, dissolved oxygen tends to accumulate in the wall portion of the crucible in contact with the molten metal, and nonmetallic inclusions formed along the wall are subjected to conventional slag refining There is a limitation that it can not be removed by the method. In addition, in the conventional slag refining method, it may be difficult to uniformly control the concentration of the impurity element that produces the nonmetallic inclusions in the molten metal, and the number of refractable elements to various impurity elements may be limited.

Therefore, in order to solve the above-mentioned problems, various methods such as an electrochemical refining technique are emerging, but a method for fundamentally solving the problems until now is not suggested.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to overcome the limitations of conventional static chemical slag refining techniques by removing impurity elements that produce nonmetallic inclusions in molten metal, And to provide a metal refining method capable of adjusting the concentration.

Another object of the present invention is to provide a metal refining apparatus having the above-described advantages.

According to an embodiment of the present invention, there is provided a method of manufacturing a molten metal, comprising the steps of: preparing a molten metal containing an impurity element and a molten metal containing slag floating on the molten metal; Contacting the cathode with the molten metal and contacting the anode with the slag to define a refining zone between the cathode and the anode; Moving the impurity element in the refining zone at an interface between the molten metal and the slag; Applying a first electric power between the anode and the cathode to ionize the impurity element moved to the interface; And removing the ionized impurity element by moving the impurity element ionized by the second power applied between the anode and the cathode to the anode through the slag. The ionizing may be performed through the first electrochemical reaction in which the impurity element is reduced by electrons emitted from the cathode by the first power. The step of removing the ionized impurity element may be performed by the second electric power through a second electrochemical reaction between the anode and the ionized impurity element. Wherein the impurity element is oxygen, the anode comprises carbon, and the second electrochemical reaction comprises: forming carbon monoxide or carbon dioxide gas by reaction of the anion of the oxygen with the carbon; And discharging the carbon monoxide gas.

In an embodiment of the present invention, before applying the first power or the second power between the anode and the cathode, achieving chemical equilibrium between the molten metal and the slag may be further included. The chemical equilibrium may comprise the step of bringing the concentration of impurities in the molten metal to chemical equilibrium. The power may be AC power or DC power.

In the embodiment of the present invention, the slag can be used as an electrolyte having an ionic conductivity with respect to the impurity element. The slag contains at least one of SiO ₂ , CaO, MgO, CaF ₂ , Al ₂ O ₃ , FeO, Na ₂ O, MnO and TiO ₂ and has the ionic conductivity at a temperature of 1,000 ° C. or higher. The impurity element may include carbon (C), nitrogen (N), sulfur (S), oxygen (O), phosphorous (P) or combinations thereof. The movement of the impurity element at the interface between the molten metal and the slag may be performed by diffusion, convection, stirring, or a combination thereof.

According to another embodiment of the present invention, there is provided an electrolytic cell comprising: an electrolytic bath containing a molten metal containing an impurity element and a molten metal containing slag floating on the molten metal; A cathode in contact with the molten metal contained in the electrolytic bath; An anode in contact with the slag received in the electrolytic bath; And a power module for applying power between the cathode and the anode, wherein a refining area is defined between the cathode and the anode, and wherein the impurity element in the refining area is an interface between the molten metal and the slag The impurity element moved to the interface is ionized through the electric power applied between the cathode and the anode by the power module and the ionized impurity element is moved to the anode through the slag A metal refining apparatus to be removed can be provided. During the application of electric power between the anode and the cathode, ionization is performed through a first electrochemical reaction in which the impurity element is reduced by electrons emitted from the cathode. The ionized impurity element is removed through a second electrochemical reaction between the anode and the ionized impurity element. Wherein the impurity element is oxygen, the anode comprises carbon, and the second electrochemical reaction includes forming a carbon monoxide gas by reaction of the anion of the oxygen with the carbon, and discharging the carbon monoxide gas A gas discharge unit may be further included. Chemical equilibrium can be achieved between the molten metal and the slag before power is applied between the anode and the cathode. The molten metal acts as the cathode, and the anode can be in contact with the slag in the form of an electrode. The concentration of the impurity element in the molten metal can be adjusted according to the intensity of electric power applied between the anode and the cathode.

According to the embodiment of the present invention, by using the electrochemical reaction using the molten slag having the ion permeability for the impurity element as the electrolyte, various impurity elements which generate the nonmetallic inclusions in the molten metal can be removed, The concentration of the target impurity element in the molten metal can be constantly controlled through the application of the electric energy and the electromagnetic field.

In addition, by removing impurities in the molten metal through electrical energy that is easy to control, high chemical cleanliness of the metal product can be increased and process stability can be improved.

1A and 1B are views showing a metal refining apparatus according to an embodiment of the present invention.
2A to 2E are views for explaining a metal refining method according to an embodiment of the present invention.
3A to 3E are views for explaining a metal refining method according to another embodiment of the present invention.
FIG. 4A is a graph showing changes in concentration of sulfur in molten metal with time according to an embodiment of the present invention, and FIG. 4B is a graph showing changes in concentration of oxygen in molten metal with time according to an embodiment of the present invention.
5 is a graph showing changes in concentration of impurities in molten metal according to an applied voltage according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, The present invention is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

Like numbers refer to like elements in the drawings. Also, as used herein, the term "and / or" includes any and all combinations of any of the listed items.

The terms used herein are used to illustrate the embodiments and are not intended to limit the scope of the invention. Also, although described in the singular, unless the context clearly indicates a singular form, the singular forms may include plural forms. Also, the terms "comprise" and / or "comprising" used herein should be interpreted as referring to the presence of stated shapes, numbers, steps, operations, elements, elements and / And does not exclude the presence or addition of other features, numbers, operations, elements, elements, and / or groups.

Reference herein to a layer formed "on" a substrate or other layer refers to a layer formed directly on top of the substrate or other layer, or may be formed on intermediate or intermediate layers formed on the substrate or other layer Layer. ≪ / RTI > It will also be appreciated by those skilled in the art that structures or shapes that are "adjacent" to other features may have portions that overlap or are disposed below the adjacent features.

As used herein, the terms "below," "above," "upper," "lower," "horizontal," or " May be used to describe the relationship of one constituent member, layer or regions with other constituent members, layers or regions, as shown in the Figures. It is to be understood that these terms encompass not only the directions indicated in the Figures but also the other directions of the devices.

In the following, embodiments of the present invention will be described with reference to cross-sectional views schematically illustrating ideal embodiments (and intermediate structures) of the present invention. In these figures, for example, the size and shape of the members may be exaggerated for convenience and clarity of explanation, and in actual implementation, variations of the illustrated shape may be expected. Accordingly, embodiments of the present invention should not be construed as limited to any particular shape of the regions shown herein. In addition, reference numerals of members in the drawings refer to the same members throughout the drawings.

1A and 1B are views showing a metal refining apparatus according to an embodiment of the present invention.

1A and 1B, the metal refining apparatus 10 includes a molten metal (LM) containing an impurity element and a molten metal (MM) containing slag MS suspended on the molten metal (LM) A cathode E2 in contact with the molten metal LM contained in the electrolyzer EE and an anode E1 and a cathode E2 in contact with molten slag MS contained in the electrolyzer EE, And a power module (PM) for applying power between the anode (E1) and the anode (E1).

In the embodiment of the present invention, a refining region is defined between the cathode E2 and the anode E1, and the impurity element can be moved to the interface between the molten metal LM and the slag MS in the refining region . The impurity element moved to the interface is ionized through the power applied between the cathode E2 and the anode E1 by the power module PM and the ionized impurity element through the slag MS Can be moved to the anode E1 and removed. Ionization can be performed through the first electrochemical reaction in which the impurity element is reduced by the electrons EC emitted from the cathode E2 while power is applied between the anode E1 and the cathode E2, The ionized impurity element can be removed through a second electrochemical reaction between the anode (E1) and the ionized impurity element.

In one embodiment, the molten metal LM acts as the cathode E2 and the anode El can be in contact with the slag MS in the form of an electrode. When the anode E1 is configured in the form of an electrode rod, a portion of the end of the electrode rod used as at least one anode can be infiltrated into the slag MS.

Also, the concentration of the impurity element in the molten metal (LM) can be adjusted depending on the intensity of electric power applied between the anode (E1) and the cathode (E2). For example, as shown in FIG. 5, as the electric power applied between the anode E1 and the cathode E2 increases, the ionization components of the impurity element increase and the concentration of the impurity element decreases. On the other hand, As the intensity of the electric power applied between the cathodes E2 becomes smaller, the ionization components of the impurity element become smaller and the concentration of the impurity element becomes higher.

In the present invention, the lead wire connecting the cathode E2 and the power module PM uses a conductor which is stable at a high temperature not lower than the melting temperature of the metal to be refined and the slag MS used as the electrolyte is melted And may include a composition having stable ion conductivity as a state.

Further, in the present invention, the polarization direction of the anode can be determined in consideration of the refining mechanism of the impurity element in the molten metal (LM). For example, in the case of an electrochemical reaction in which sulfur (S) in molten metal (LM) is removed, sulfur is removed through a reduction reaction that becomes a sulfur ion by receiving two electrons, The cathode may be determined, and the opposite electrode may be determined as the anode. Alternatively, since the impurity element is removed through an oxidation reaction that provides two electrons to become a cation, it is determined as an anode in the case of an electrode contacting with the molten metal (LM), and the opposite electrode can be determined as a cathode.

For example, when the impurity element is oxygen and the anode (E1) contains a carbon component, a carbon monoxide gas may be formed by the reaction of the carbon with the anion of the oxygen by an electrochemical reaction.

In one embodiment, the electrolyzer EE is a part of the interior of the crucible CC or the electrolyzer EE is disposed inside the crucible CC so that the outer wall of the electrolyzer EE is in contact with the outer wall of the crucible CC . The crucible (CC) may be composed of a carbon component, but the present invention is not limited thereto. Further, the crucible CC may have thermal conductivity so that the heat from the heating element HE, which will be described later, is transferred to the electrolytic bath EE. The heating element HE may include a Kanthal Heating Element, but the present invention is not limited thereto and various heating elements may be used.

In the embodiment of the present invention, the refractory auxiliary material RS supporting the electrolytic bath EE and the stainless steel (stainless steel) pipe covering the upper part of the crucible CC are arranged so that the electrolytic bath EE is located at the central portion inside the crucible CC. Cap) (SC) may be further included. The stainless gap SC is connected to the cooling water inlet WI and the cooling water outlet WO and can also be connected to the gas inlet GI and the gas outlet GO.

In one example of the present invention, carbon monoxide (CO) gas is introduced into the electrolytic bath (EE) through the gas inlet (GI) before electrical energy is applied so that chemical equilibrium is achieved between molten slag (MS) ). ≪ / RTI > Further, the gas (for example, carbon monoxide or carbon dioxide gas) formed through the electrochemical reaction between the ionized impurity element and the anode can be discharged to the outside through the gas discharge portion GO.

Referring again to FIG. 1B, an electrolytic bath EE may be configured to generate an electrochemical reaction, and then an electric energy and an electromagnetic field may be applied to the electrolytic bath EE by connecting the electrolytic bath to an external power module PM. The applied electrical and electromagnetic fields can induce an electrochemical refining reaction of the impurity element at the interface between the molten metal (LM) and the slag (MS) to achieve local electrochemical equilibrium.

Therefore, the concentration of the impurity element in the molten metal LM can be controlled by the electric energy and the electromagnetic field applied through the power module PM. In addition to the conventional slag refining reaction, by using the electrochemical energy and the electromagnetic field as a new reaction driving force , It is easy to control during the process, and it is possible to reduce the use of additives (for example, CaO, deoxidizing agent, etc.) conventionally required for the chemical refining reaction. Further, the present invention can remove the impurity element in slag form in molten metal (LM) through an electrochemical local equilibrium technique. In addition, the electrochemical refining method using slag can be applied to various impurity elements having ion conductivity of slag (MS), and it is possible to apply the electric energy and the electromagnetic field using an external power source to the concentration of the impurity element in the molten metal Can be constantly controlled. According to the metal refining technique using the electrochemical local equilibrium technique of the present invention, by removing the impurity element in the molten metal through electrical energy, the chemical cleanliness of the metal product can be increased and the process stability can be improved.

2A to 2E are views for explaining a metal refining method according to an embodiment of the present invention.

Referring to FIG. 2A, a molten metal LM containing impurity elements IM1, IM2, IM3 and IM4 and a molten slag MS floating on the molten metal LM are placed in an electrolytic cell EE of a steel process. The molten metal (MM) containing the molten metal can be produced. In one embodiment of the present invention, an electrochemical reaction for removing the impurity elements IM1, IM2, IM3, and IM4 in the electrolytic bath EE or for controlling the concentrations of the impurity elements IM1, IM2, IM3, and IM4 The cathode E2 may be brought into contact with the molten metal LM and the anode E1 may be brought into contact with the slag MS and an electrochemical reaction may occur between the cathode E2 and the anode E1 A refining region SR can be defined.

In one embodiment, the anode E1 may be contacted on at least a portion or the entire surface of the slag MS and, similarly, the cathode E2 may be contacted on at least a portion or the entire surface of the molten metal LM . In another embodiment, molten metal (LM) itself can be used or act as cathode E2. Alternatively, the slag MS itself may be used or operated as the anode El.

In the embodiment of the present invention, the impurity elements IM1, IM2, IM3 and IM4 in the refining region SR can be moved to the interface IF1 between the molten metal LM and the slag MS through mass transfer have.

Slag (MS) is used as an electrolyte having ion conductivity with respect to the impurity element (IM1, IM2, IM3, IM4 ), SiO 2, CaO, MgO, CaF 2, Al 2 O 3, FeO, Na 2 O, MnO, TiO ₂ may include at least one or more of the However, the slag MS is not limited thereto. For example, the slag MS can be used as long as it can be used as an electrolyte having an ionic conductivity with respect to an impurity element. In addition, the slag MS can have a higher ionic conductivity at a temperature higher than 1,000 DEG C above the low temperature.

The impurity elements IM1, IM2, IM3 and IM4 may be carbon, nitrogen, sulfur, oxygen, phosphorus, silicon, manganese, And the mass transfer may include diffusion, convection by heat transfer, agitation, or a combination thereof. However, in the embodiment of the present invention, the types and the number of the impurity elements IM1, IM2, IM3, IM4 and the kind of the substance movement are not limited thereto.

가 슬래그 내에서 안정한 이온상으로 존재하기 때문에, 다른 불순물 원소들과 다르게 산화 반응을 통해서 제거될 수 있다. 이때, 인가 전압은 다른 불순물 원소(S, O, N, C)의 인가 전압과 반대 방향으로 제공될 수 있다. 예컨대, 인(P)의 경우, E1은 캐소드가 되고, E2는 애노드가 될 수 있다. In the present invention, one kind of impurity element IM1, IM2, IM3, IM4 may be contained in the molten metal LM or various kinds of impurity elements IM1, IM2, IM3, IM4 may be contained in the molten metal LM have. The type of the anode E1 can also be determined depending on the kind of the impurity element in the anode E1. For example, in order to remove oxygen or control the concentration, the anode E1 contains a carbon component, and in order to remove or control the concentration of nitrogen (N), the anode E1 reacts with nitrogen, (E1) comprises a component capable of reacting with sulfur to produce a sulfur dioxide gas, and the carbon (C) is reacted with sulfur In order to remove or control the concentration, the anode (E1) may contain a component capable of reacting with carbon to produce carbon dioxide gas. In the case of phosphorus (P)

Is present in the stable ionic phase in the slag, it can be removed through an oxidation reaction differently from other impurity elements. At this time, the applied voltage may be provided in the opposite direction to the applied voltage of the other impurity element (S, O, N, C). For example, in phosphorus (P), E1 may be the cathode and E2 may be the anode.

Referring to FIG. 2B, the first power PS1 is applied between the anode E1 and the cathode E2, and the impurity elements IM1, IM2, IM3, and IM4 moved to the interface IF1 may be ionized . Here, the ionized impurity element is defined as IM1 ⁺ , IM2 ⁺ , IM3 ⁺ , and IM4 ⁺ . The ionization may be performed through a first electrochemical reaction (CR1) in which impurity elements IM1, IM2, IM3 and IM4 are reduced by electrons EC emitted from the cathode E2. The first electrochemical reaction (CR1) may be defined by the following formula (1).

Formula 1

The impurity elements IM1 +, IM2 +, IM3 +, and IM4 + ionized by the second power PS2 applied between the anode E1 and the cathode E2 are connected to the impurity elements IM1, IM2, IM3, IM4) to the anode (E1) through the slag (MS) used as an electrolyte having ionic conductivity. At this time, the ionized impurity elements IM1 ⁺ , IM2 ⁺ , IM3 ⁺ and IM4 ⁺ are present at the interface IF2 between the slag MS and the anode E1.

Referring to Figure 2d, the ionized impurity element ^{(IM1 +, IM2 +, IM3} +, IM4 +), a second power (PS2), an anode (E1) and the ionized impurity element (IM1 ⁺ by to remove, IM2 ⁺ , IM3 ⁺ , IM4 ⁺ ) can be performed. For example, the impurity element is oxygen (O) and, when the anode (E1) comprise a carbon element (C), the second electrochemical reaction (CR2) is, to the anion of the oxygen of the general formula 2 (O ^2-) and carbon Carbon monoxide (CO) or carbon dioxide (CO2) gas can be formed by the reaction of step (C).

(2)

In one embodiment, when the impurity element is sulfur (S) and the anode (E1) comprises a carbon element (C), the second electrochemical reaction (CR2) It can be formed into a sulfur gas without reacting with the carbon electrode.

(3)

In one embodiment, when the impurity element is nitrogen (N) and the anode (E1) comprises a carbon element (C), the second electrochemical reaction (CR2) comprises an anion of nitrogen (N3-) And nitrogen gas without reacting with the carbon electrode.

Formula 4

In another embodiment, when the impurity element is phosphorus (P) or carbon (C), the impurity element can be removed by an oxidation reaction between the anode and the ion phase of the impurity element (P, C). Preferably, in the present invention, the free oxygen ions O ^2- is based on formula (2) a second electrochemical reaction (CR2) to produce a CO gas react with the carbon electrode can take place predominantly other than the second electrochemical reaction (CR2) have.

In one embodiment, the first power PS1 and the second power PS2 may be AC power or DC power. The first power PS1 and the second power PS2 are the same power and the first power PS1 is a power applied at a first time preceding the second time and the second power PS2 is a power applied to the second Lt; / RTI > may be the power applied over time. In another embodiment, the first power PS1 and the second power PS2 are powers having different magnitudes, the first power PS1 is a power applied at a first time preceding the second time, (PS2) may be the power applied at the second time. For example, the first power PS1 may be higher or lower than the second power PS2. Or the first power PS1 may be DC power and the second power PS2 may be AC power. Conversely, the first power PS1 may be AC power and the second power PS2 may be DC power. However, the present invention is not limited thereto, and the first power (PS1) and the second power (PS2) may be selected in consideration of the speed of the first electrochemical reaction (CR1) and the speed of the second electrochemical reaction The second power PS2 can be determined.

2E, gases of the impurity element produced by the second electrochemical reaction (CR2) are discharged through the gas outlet GO, whereby the impurity element in the molten metal LM is removed or the molten metal LM ) Can be controlled.

The impurity elements IM1 ⁺ , IM2 ⁺ , IM3 ⁺ , IM4 ⁺ ionized by the second electric power PS2 applied between the anode E1 and the cathode E2 are supplied to the interface E1 via the slag MS Can be moved to and removed from the interface IF2 between the slag MS and the anode E1.

In one embodiment of the present invention, before the first power PS1 or the second power PS2 is applied between the anode E1 and the cathode E2, chemical equilibrium between the molten metal LM and the slag MS Can be achieved. Here, the chemical equilibrium means that the concentrations of the impurity elements IM1, IM2, IM3 and IM4 in the molten metal LM reach chemical equilibrium.

3A to 3E are views for explaining a metal refining method according to another embodiment of the present invention.

The five steps of FIGS. 3A to 3E are the same as the five steps of FIG. 2A to FIG. 2E described above, and the description of the five steps of FIG. 2A to FIG.

3A to 3E, the anode E1 is in the form of a rod, and at least a part of the rod is infiltrated into the slag MS to cause an electrochemical reaction, whereas in FIGS. 2A to 2E, the anode E1 is slag MS) so that an electrochemical reaction takes place.

As described above, the impurity elements IM1, IM2, IM3 and IM4 in the molten metal LM through the slag MS can be removed through five steps. The first step is to move the impurity elements IM1, IM2, IM3 and IM4 in the molten metal LM to the interface between the molten metal LM and the slag MS through mass transfer. Here, the moving speed can be determined by stirring the molten metal (LM). The second step is the first electrochemical reaction that occurs at the interface between the molten metal (LM) and the slag (MS). In the third step, ionized impurity elements (IM1 ⁺ , IM2 ⁺ , IM3 ⁺ , IM4 ⁺ ) move according to the ion conductivity of the slag (MS). The fourth step is a second electrochemical reaction step occurring at the interface between the slag MS and the anode E1 (e.g. graphite electrode). At this time, the generated electrons move through the electrochemical circuit. The last five steps are reactions in which the adsorbed gaseous gas produced through the second electrochemical reaction is desorbed and removed. The impurity elements IM1, IM2, IM3 and IM4 in the molten metal LM can be removed by an electrochemical local equilibrium method through these five steps. In the invention, the electrochemical local equilibrium technique is a local equilibrium generated at the interface between the molten metal and the slag. As the electric power is applied instead of the chemical equilibrium formed at the interface between the conventional molten metal and the slag, the physical properties of the slag are changed But it means a technique of improving the refining ability through the phenomenon that the impurities are further moved by the electrochemical equilibrium at the interface.

Experimental Example

Prior to the application of electric energy, carbon monoxide (CO) gas is supplied constantly at a rate of 300 mL / min into the electrolytic cell at about 1500 ° C. before electrical energy is applied so that chemical equilibrium is achieved between molten slag (MS) and molten metal (LM) . This allows the concentration of impurities in the molten metal (LM) to reach chemical equilibrium by maintaining the oxygen partial pressure constant at the interface between the molten slag (MS) and the molten metal (LM) through the equilibrium reaction of the following formula (X).

Equation 1

Where k is the equilibrium constant and T is the absolute temperature of the molten metal.

Slag containing silicon oxide (SiO2), calcium oxide (CaO) and aluminum oxide (Al2O3) was used as the slag having the same ion conductivity with respect to the impurities. The slag containing sulfur (S) and Oxygen (O) was used, and DC voltage was used as electric energy.

FIG. 4A is a graph showing changes in concentration of sulfur in molten metal with time according to an embodiment of the present invention, and FIG. 4B is a graph showing changes in concentration of oxygen in molten metal with time according to an embodiment of the present invention.

Referring to FIG. 4A, the sulfur concentration in the molten metal after reaching the initial chemical equilibrium was approximately 636 ppm, and the sulfur concentration continuously decreased from the point of application of 1 V of electric energy, reaching approximately 292 ppm after 18 hours.

Referring to FIG. 4B, the oxygen concentration in the molten metal after reaching the initial chemical equilibrium was approximately 71.3 ppm, and the concentration of oxygen continuously decreased from the point of application of 1 V of electric energy, reaching approximately 15.3 ppm after 14 hours .

It is known that the local equilibrium of slag and molten metal interface through electrochemical reaction reaches relatively fast time, but the reason for the long time like the test result of FIG. 4A is that the above- This is probably due to the first and third steps. Thus, impurities can be removed more quickly if physical stirring is carried out in the first or third stage.

5 is a graph showing changes in concentration of impurities in molten metal according to an applied voltage according to an embodiment of the present invention.

Referring to FIG. 5, when 1 V of electric energy is applied, the concentrations of sulfur and oxygen are about 292 ppm and about 71.3 ppm, respectively, and the concentrations of sulfur and oxygen are about 205 ppm and about 49 ppm, respectively, . As the applied electric energy increases, the ionization becomes more active and the concentration of the impurities (for example, sulfur or oxygen) in the molten metal decreases. That is, it can be confirmed that the concentration of the impurity element in the molten metal can be controlled according to the magnitude of the applied electric power.

 The present invention includes a refining technique using an electrochemical local equilibrium technique in order to maximize the workability and alloy design capability of a high strength material through control of the impurity element component (eg, C, N, S, O, P) do. The electrochemical local equilibrium technique of the present invention uses electric energy as compared with the conventional slag refining method, so that it is easier to control during the process than the conventional method, and the process is stable, and additionally the contamination of molten metal can be reduced, Can be improved. Further, by using molten slag having ion permeability to an impurity element as an electrolyte, it is possible to remove various impurity elements or to control the concentration of impurities.

According to the present invention, impurity elements in molten metal can be controlled by applying electric energy and an electromagnetic field. In addition to the conventional slag refining reaction, by using the electrochemical energy and the electromagnetic field as a new reaction driving force, It is possible to reduce the use of additives (CaO, deoxidant, etc.)

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be clear to those who have knowledge.

10: Metal refining device
LM: Molten metal
MS: slag
MM: molten metal
EE: electrolytic bath
E2: cathode,
E1: anode
PM: Power module

Claims (18)

Preparing a molten metal containing an impurity element in the electrolytic bath and a molten metal containing slag floating on the molten metal;
A first electrode of the cathode and the anode is brought into contact with the molten metal contained in the electrolytic bath, and a refining region is defined on the interface between the slag and the molten metal, and the molten metal outside the refining region, Spacing one electrode apart;
Contacting the cathode and the second electrode of the other one of the anodes with the slag received in the electrolytic bath;
Applying a first electric power between the first electrode and the second electrode to ionize the impurity element moved to the interface; And
And moving the impurity element ionized by the second power applied between the first electrode and the second electrode to the second electrode through the slag to remove the ionized impurity element. The method according to claim 1,
The ionizing step comprises:
Wherein the impurity element is reduced by electrons emitted from the cathode among the first electrode and the second electrode by the first electric power through a first electrochemical reaction. The method according to claim 1,
The step of removing the ionized impurity element includes:
And performing the second electrochemical reaction between the second electrode and the ionized impurity element by the second electric power. The method of claim 3,
Wherein the impurity element is oxygen, and the anode of the first electrode and the second electrode includes carbon,
The second electrochemical reaction may include: forming carbon monoxide or carbon dioxide gas by reaction of the carbon with the anion of the oxygen; And
And discharging the carbon monoxide gas. The method of claim 1, wherein
Further comprising the step of achieving chemical equilibrium between the molten metal and the slag before applying the first power or the second power between the first electrode and the second electrode. The method of claim 5, wherein
Wherein the chemical equilibrium includes the step of reaching a chemical equilibrium concentration of impurities in the molten metal. The method of claim 1, wherein
Wherein the power is AC power or DC power. The method according to claim 1,
Wherein the slag is used as an electrolyte having an ionic conductivity with respect to the impurity element. 9. The method of claim 8,
Wherein the slag contains at least one of SiO ₂ , CaO, MgO, CaF ₂ , Al ₂ O ₃ , FeO, Na ₂ O, MnO and TiO ₂ and has the ionic conductivity at a temperature of 1,000 ° C. or higher. The method of claim 1, wherein
Wherein the impurity element comprises carbon (C), nitrogen (N), sulfur (S), oxygen (O), phosphorus (P) or a combination thereof. The method of claim 1, wherein
Wherein the movement of the impurity element at the interface between the molten metal and the slag is performed by diffusion, convection, stirring, or a combination thereof. An electrolytic bath containing a molten metal containing an impurity element and a molten metal containing slag floating on the molten metal;
A first electrode, which is in contact with the molten metal accommodated in the electrolytic bath and has a refining region defined on an interface between the slag and the molten metal and spaced apart from the molten metal outside the refining region, ;
A second electrode in the other of the cathode and the anode that is in contact with the slag received in the electrolytic bath; And
And a power module for applying power between the first electrode and the second electrode,
The impurity element moved to the interface is ionized through the electric power applied between the first electrode and the second electrode by the power module, and the ionized impurity element is transferred to the second electrode through the slag A metal refining apparatus which is moved and removed. 13. The method of claim 12,
Wherein during the application of the electric power between the first electrode and the second electrode, ionization is performed through a first electrochemical reaction in which the impurity element is reduced by electrons emitted from the cathode among the first electrode and the second electrode Is performed. 13. The method of claim 12,
Wherein the ionized impurity element is removed through a second electrochemical reaction between the second electrode and the ionized impurity element. 14. The method of claim 13,
Wherein the impurity element is oxygen, and the anode of the first electrode and the second electrode includes carbon,
Wherein the second electrochemical reaction comprises forming a carbon monoxide gas by reaction of the carbon with an anion of the oxygen,
And a gas discharging portion for discharging the carbon monoxide gas. The method of claim 12, wherein
Wherein chemical equilibrium is achieved between the molten metal and the slag before power is applied between the first electrode and the second electrode. 13. The method of claim 12,
The molten metal serving as the first electrode,
And the second electrode is in contact with the slag in the form of an electrode. 13. The method of claim 12,
Wherein a concentration of the impurity element in the molten metal is adjusted according to an intensity of electric power applied between the first electrode and the second electrode.

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