Apparatus and method for removing light alkali metals contained in molten aluminum

Abstract

The present invention relates to an apparatus and a method for removing light alkali metals contained in molten aluminum, the apparatus comprising a flux supply unit for light alkali metal removal and a stirring unit. The flux supply unit supplies a flux for light alkali metal removal to the surface of molten aluminum in a state where the light alkali metals contained in the molten aluminum are floating on the surface or in the surface layer of the molten aluminum by utilizing the specific gravity difference between aluminum and the light alkali metals. The stirring unit stirs the surface layer of the molten aluminum and the flux so that the light alkali metals react with the flux.

Description

Device and method for removing alkaline light metals contained in molten aluminum

[0001] The present invention relates to a device and method for removing alkaline light metals such as lithium (Li) and sodium (Na) contained in molten aluminum.

[0002] Many aluminum products used in automobiles, home appliances, and building materials are primarily manufactured using aluminum casting equipment. Aluminum melting furnaces supply molten aluminum to these casting equipment. These furnaces are designed to melt aluminum at high temperatures, allowing for its refinement.

[0003] However, molten aluminum stored in an aluminum melting furnace frequently contains alkaline metals, such as lithium or sodium, as impurities. Manufacturing products using molten aluminum containing these alkaline metals can lead to softening of the aluminum, which reduces the tensile strength of the aluminum and products manufactured from it.

[0004] To solve this problem, in the past, fluoride fluxes such as AlF3 were added to molten aluminum to remove alkaline light metals contained in the molten aluminum. According to these conventional alkaline light metal removal methods, not only was it difficult to smoothly contact and react the alkaline light metals widely distributed in a low concentration in the molten aluminum with the fluoride flux, but the alkaline light metal removal efficiency was low due to the low alkaline light metal removal performance of the fluoride flux itself, and there was a problem that environmental pollution occurred due to the large amount of fluoride flux generated to increase the alkaline light metal removal efficiency, such as fluoride waste dross.

[0005] The problem to be solved by the present invention is to provide an improved device and method for removing alkaline light metals contained in molten aluminum, which are capable of improving the removal efficiency of alkaline light metals such as lithium or sodium contained in molten aluminum, in order to solve the problems of the above-described prior art.

[0006] According to a preferred embodiment of the present invention for solving the above-described problem, a device for removing an alkaline light metal contained in a molten aluminum includes: an alkaline light metal removal flux supply unit that floats the alkaline light metal contained in the molten aluminum using the difference in specific gravity between aluminum and the alkaline light metal and collects it on the surface or surface layer of the molten aluminum, and supplies an alkaline light metal removal flux to the surface of the molten aluminum; and a stirring unit that stirs the surface layer of the molten aluminum and the alkaline light metal removal flux so that the alkaline light metal is removed from the molten aluminum by a reaction between the alkaline light metal and the alkaline light metal removal flux.

[0007] The above alkaline light metal may include at least one of lithium and sodium.

[0008] Preferably, the method further comprises a dross treatment flux supply unit for supplying a dross treatment flux to the dross floating on the surface of the molten aluminum; and a dross recovery unit for recovering black dross formed by treating the dross with the dross treatment flux to make the molten aluminum into a bare state, wherein the alkaline light metal removal flux supply unit supplies the alkaline light metal removal flux after allowing the molten aluminum to stand by in a calm state for a predetermined standard collection time until the alkaline light metal is collected on the surface or surface layer of the molten aluminum due to the specific gravity difference when the molten aluminum is in the bare state.

[0009] Preferably, the flux for dross treatment contains 35 wt% of NaCl, 25 wt% of KCl, 15 wt% of AlF3, 5 wt% of KAlF4, 10 wt% of NaNO3, and 10 wt% of Na2SO4.

[0010] Preferably, the method further includes a flattening unit that flattens the alkaline light metal removal flux distributed on the surface of the aluminum molten metal by the alkaline light metal removal flux supply unit, and the stirring unit stirs the alkaline light metal removal flux and the surface layer of the aluminum molten metal while the alkaline light metal removal flux is flattened.

[0011] Preferably, the stirring unit repeatedly pushes and pulls the alkaline light metal removal flux distributed on the surface of the molten aluminum and the surface layer of the molten aluminum in a horizontal direction forward and backward or repeatedly taps the alkaline light metal removal flux distributed on the surface of the molten aluminum toward the surface layer of the molten aluminum to stir the surface layer of the molten aluminum and the alkaline light metal removal flux.

[0012] Preferably, the flux for removing the alkaline light metal contains 40 to 60 wt% of MgCl2, 40 to 60 wt% of KCl, and 0 to 5 wt% of KAlF4.

[0013] According to another preferred embodiment of the present invention for solving the above-described problem, a method for removing an alkaline light metal contained in a molten aluminum includes: (A) a step of floating the alkaline light metal contained in the molten aluminum using the difference in specific gravity between aluminum and the alkaline light metal to collect it on the surface or surface layer of the molten aluminum; (B) a step of supplying a flux for removing an alkaline light metal to the surface of the molten aluminum; and (C) a step of stirring the surface layer of the molten aluminum and the flux for removing the alkaline light metal to remove the alkaline light metal from the molten aluminum using the flux for removing the alkaline light metal.

[0014] The above alkaline light metal may include at least one of lithium and sodium.

[0015] Preferably, in the step (A), the aluminum molten metal is allowed to stand in a calm state for a predetermined standard collection time until the alkaline light metal floats due to the specific gravity difference and gathers on the surface or superficial layer of the aluminum molten metal.

[0016] Preferably, (D) is performed before step (A) and further includes a step of making the molten aluminum into a bare state.

[0017] Preferably, the step (D) comprises: (D2) a step of supplying a dross treatment flux to the dross floating on the surface of the molten aluminum; and (d2) a step of recovering black dross formed by treating the dross with the dross treatment flux from the surface of the molten aluminum, thereby making the molten aluminum into the bare state.

[0018] Preferably, the flux for dross treatment contains 35 wt% of NaCl, 25 wt% of KCl, 15 wt% of AlF3, 5 wt% of KAlF4, 10 wt% of NaNO3, and 10 wt% of Na2SO4.

[0019] Preferably, the step (B) comprises: (b1) a step of spraying the alkaline light metal removal flux on the surface of the aluminum molten metal; and (b2) a step of flattening the alkaline light metal removal flux sprayed in the step (b1).

[0020] Preferably, in the step (C), the alkaline light metal removal flux distributed on the surface of the molten aluminum and the surface layer of the molten aluminum are repeatedly pushed and pulled in a horizontal direction forward and backward, or the alkaline light metal removal flux distributed on the surface of the molten aluminum are repeatedly struck toward the surface layer of the molten aluminum to mix the surface layer of the molten aluminum and the alkaline light metal removal flux.

[0021] Preferably, the flux for removing the alkaline light metal contains 40 to 60 wt% of MgCl2, 40 to 60 wt% of KCl, and 0 to 5 wt% of KAlF4.

[0022] The present invention relates to a device and method for removing alkaline light metals contained in molten aluminum, and has the following effects.

[0023] First, the present invention utilizes the difference in specific gravity between aluminum and an alkaline light metal to float the alkaline light metal contained in the aluminum molten metal and collect it at a high concentration on the surface or surface of the aluminum molten metal, and then supplies a flux for removing the alkaline light metal to the surface of the aluminum molten metal, thereby improving the contact and reaction efficiency between the alkaline light metal and the flux for removing the alkaline light metal, thereby efficiently removing the alkaline light metal from the aluminum molten metal.

[0024] Second, the present invention performs an alkaline light metal removal operation using an alkaline light metal removal flux while treating and removing dross generated during the aluminum melting process to make the aluminum molten metal into a bare state using a dross treatment flux. Through this, the present invention prevents dross from interfering with the contact and reaction between the alkaline light metal and the alkaline light metal removal flux, thereby more efficiently removing the alkaline light metal from the aluminum molten metal.

[0025] Third, the present invention performs the alkaline light metal removal operation by stirring the alkaline light metal removal flux supplied to the surface of the molten aluminum and the surface layer of the molten aluminum in which the alkaline light metal is collected at a high concentration so as to be evenly mixed with each other, thereby removing the alkaline light metal from the molten aluminum more efficiently.

[0026] Fourth, the present invention removes alkaline light metals contained in molten aluminum using a flux for removing alkaline light metals composed of chloride and a small amount of fluoride, thereby removing alkaline light metals from molten aluminum more efficiently and preventing environmental pollution caused by the use of a large amount of fluoride.

[0027] FIG. 1 is a block diagram illustrating the configuration of a device for removing alkaline light metals contained in molten aluminum according to a preferred embodiment of the present invention.

[0028] FIG. 2 is a drawing showing how the flux for dross treatment is supplied by the flux supply unit for dross treatment of FIG. 1.

[0029] Figure 3 is a drawing showing how black dross is recovered by the dross recovery unit of Figure 1.

[0030] Figure 4 is a drawing showing the appearance of the molten aluminum of Figure 1 in a bare state.

[0031] Figure 5 is a drawing showing the appearance of alkaline light metals contained in molten aluminum gathering on the surface or superficial layer of the molten aluminum.

[0032] Fig. 6 is a drawing showing how a flux for removing alkaline light metals is supplied by the flux supply unit for removing alkaline light metals of Fig. 1.

[0033] FIG. 7 and FIG. 8 are drawings showing the appearance of the flux for removing alkaline light metal being evenly distributed on the surface of the molten aluminum by the flattening unit of FIG. 1.

[0034] FIG. 9 and FIG. 10 are drawings showing the reaction between the alkaline light metal and the alkaline light metal removing flux as the surface layer of the molten aluminum is mixed with the alkaline light metal removing flux by the stirring unit of FIG. 1.

[0035] FIG. 11 is a flowchart for explaining a method for removing alkaline light metals contained in molten aluminum using an alkaline light metal removal device shown in FIG. 1.

[0036] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components will be given the same reference numerals, even if they appear in different drawings. Furthermore, when describing embodiments of the present invention, detailed descriptions of related known structures or functions will be omitted if they are deemed to hinder understanding of the embodiments of the present invention.

[0037] In describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by these terms. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this application.

[0038] FIG. 1 is a block diagram illustrating the configuration of a device for removing alkaline light metals contained in molten aluminum according to a preferred embodiment of the present invention.

[0039] Referring to FIG. 1, a device (1) for removing alkaline light metal contained in an aluminum molten metal according to a preferred embodiment of the present invention may include a flux supply unit (10) for dross treatment, a dross recovery unit (20), a flux supply unit (30) for removing alkaline light metal, a stirring unit (40), etc.

[0040] The device (1) for removing alkaline light metals contained in molten aluminum can be applied to various devices that receive molten aluminum (M), such as an aluminum melting furnace (2) for melting aluminum, an aluminum holding furnace (not shown) for maintaining the temperature of the molten aluminum (M) delivered from the aluminum melting furnace (2), etc. For the convenience of explanation, the present invention will be described below by taking as an example a case where the device (1) for removing alkaline light metals contained in molten aluminum is applied to an aluminum melting furnace (2).

[0041] FIG. 2 is a drawing showing how the flux for dross treatment is supplied by the flux supply unit for dross treatment of FIG. 1.

[0042] First, the flux supply unit (10) for dross treatment is a device that supplies flux (F1) for dross treatment to treat dross (D1) floating on the surface (S) of molten aluminum (M) contained in an aluminum melting furnace (2).

[0043] In general, in the process of melting aluminum in molten aluminum (M), dross (D1) is generated in which aluminum particles, aluminum oxide, non-metallic inclusions, etc. are aggregated. This dross (D1) expands during the generation process to have a lower specific gravity than molten aluminum. Accordingly, as illustrated in FIG. 2, the dross (D1) floats to the surface (S) of the aluminum molten aluminum (M) and then floats along the surface (S) of the aluminum molten aluminum (M). The dross treatment flux supply unit (10) is provided so as to spray or otherwise supply the dross treatment flux (F1) to the dross (D1) floating on the surface (S) of the aluminum molten aluminum (M).

[0044] The composition of the flux (F1) for dross treatment is not particularly limited. For example, the flux (F1) for dross treatment may contain chloride, fluoride, a heating agent, an auxiliary agent, etc.

[0045] Chloride has the function of improving the flowability of molten aluminum coarsely divided by a heating agent, thereby recovering molten aluminum contained in dross (D1) into molten aluminum (M), and the function of alleviating the oxidation reaction within the dross treatment flux (F1) to prevent the reaction from proceeding explosively. The type of compound that can be applied as a chloride to the dross treatment flux (F1) is not particularly limited. For example, the chloride may be any one selected from the group consisting of NaCl, KCl, or a mixture thereof.

[0046] Fluoride has the function of improving the separation ability of molten aluminum and dross (D1) by weakening the attractive force between them, and also functions as an auxiliary heating agent to assist the heating agent. The type of compound that can be applied as a fluoride to the flux (F1) for dross treatment is not particularly limited. For example, the fluoride may be any one selected from the group consisting of AlF3, KAlF4, Na2SiF6, or a mixture thereof.

[0047] The heating agent has the function of providing heat that allows the aluminum particles contained in the dross (D1) to melt smoothly through instantaneous heating. The type of compound that can be applied as a heating agent to the dross processing flux (F1) is not particularly limited. For example, the heating agent may be NaNO3.

[0048] The adjuvant has the function of controlling the violent exothermic reaction of the exothermic agent and maintaining the exothermicity of the exothermic agent. The type of compound that can be used as an adjuvant in the flux (F1) for dross processing is not particularly limited, and the adjuvant may be sulfur oxide, which is a weaker oxidizing agent than the exothermic agent. For example, the adjuvant may be Na2SO4.

[0049] The content ratios of the above-mentioned chlorides, fluorides, heat-generating agents, and auxiliary agents are not particularly limited. For example, the flux (F1) for dross treatment may contain 40 to 60 wt% of chloride, 10 to 30 wt% of fluoride, and 10 to 25 wt% of heat-generating agents and auxiliary agents. More preferably, the flux (F1) for dross treatment may contain 35 wt% of NaCl, 25 wt% of KCl, 15 wt% of AlF3, 5 wt% of KAlF4, 10 wt% of NaNO3, and 10 wt% of Na2SO4.

[0050] When this dross treatment flux (F1) is sprayed on the dross (D1) floating on the surface (S) of the molten aluminum (M), the molten aluminum contained in the dross (D1) is separated from the dross (D1) and recovered as the molten aluminum (M), and the dross (D1) from which the molten aluminum is separated in this way reduces in volume and becomes black dross (black dross; D2).

[0051] As described above, the dross processing flux (F1) is supplied by the dross processing flux supply unit (10) described above, but is not limited thereto. That is, the dross processing flux (F1) may be supplied using a device or method other than the dross processing flux supply unit (10), such as a method of injecting the dross processing flux (F1) into the dross (D 1) using a work vehicle (e.g., a shovel), or injecting a synthetic resin bag (e.g., a PE bag) containing the dross processing flux (F1) into the dross (D 1).

[0052] Fig. 3 is a drawing showing the state in which black dross is recovered by the dross recovery unit of Fig. 1, and Fig. 4 is a drawing showing the state in which the molten aluminum of Fig. 1 is in a bare state.

[0053] Next, the dross recovery unit (20) is a device for recovering black dross (D2) floating on the surface (S) of the aluminum molten metal (M) in a state treated with a dross treatment flux (F1).

[0054] The structure of the dross recovery unit (20) is not particularly limited. For example, as illustrated in FIG. 3, the dross recovery unit (20) may be configured to push or pull black dross (D2) floating on the surface (S) of the molten aluminum (M) and collect it in one area of ​​the aluminum melting furnace (2) or scoop it out from the molten aluminum (M) and discharge it to the outside.

[0055] As illustrated in FIG. 4, this dross recovery unit (20) can recover the aforementioned black dross (D2) and other foreign substances composed of oxides or inclusions from the surface (S) of the molten aluminum (M), thereby making the molten aluminum (M) into a bare state in which the black dross (D2) and other foreign substances are not distributed on the surface (S). According to this bare state, it is possible to prevent the black dross (D2) and other foreign substances from interfering with the contact and reaction between the alkaline light metal contained in the molten aluminum (M) and the alkaline light metal removal flux (F2) supplied from the alkaline light metal removal flux supply unit (30) to be described later. In the present invention, the alkaline light metal to be removed from the molten aluminum may be at least one selected from lithium (Li), sodium (Na), and potassium (K), which are alkaline metals but have a large difference in specific gravity from aluminum, and more specifically, may be at least one selected from lithium (Li) and sodium (Na).

[0056] FIG. 5 is a drawing showing an aspect in which an alkaline light metal removal flux is supplied by the alkaline light metal removal flux supply unit of FIG. 1, FIG. 6 is a drawing showing an aspect in which alkaline light metal contained in the molten aluminum is gathered on the surface or superficial layer of the molten aluminum, and FIGS. 7 and 8 are drawings showing an aspect in which an alkaline light metal removal flux is evenly distributed on the surface of the molten aluminum by the flattening unit of FIG. 1.

[0057] Next, the alkaline light metal removal flux supply unit (30) is a device that supplies an alkaline light metal removal flux (F2) to selectively remove alkaline light metals such as lithium or sodium, which are impurities contained in the aluminum molten metal (M), from the aluminum molten metal (M).

[0058] As shown in Fig. 5, the flux supply unit (30) for removing alkaline light metals is provided so as to spray or otherwise supply the flux (F2) for removing alkaline light metals to the surface (S) of the molten aluminum (M).

[0059] [Table 1]

[0060]

[0061] As shown in Table 1 above, alkaline light metals such as lithium (Li) and sodium (Na) have lower specific gravity than aluminum (Al). Accordingly, as shown in Fig. 6, when the stirring device (not shown) installed in the aluminum melting furnace (2) for stirring the molten aluminum (M) and the driving device capable of flowing the molten aluminum (M) are stopped to allow the molten aluminum (M) to stand by in a calm state where the flow has stopped or only a slight flow exists, lithium or sodium floats due to the difference in specific gravity with aluminum and gradually gathers on the surface (S) of the molten aluminum (M) or a surface layer (Ls) adjacent to the surface (S). Accordingly, the flux supply unit (30) for removing alkaline light metals is driven to supply the flux (F2) for removing alkaline light metals to the surface (S) of the molten aluminum (M) which has been left in a calm state for a predetermined standard collection time until lithium or sodium is gradually collected on the surface (S) or surface layer (Ls) of the molten aluminum (M) due to the specific gravity difference and distributed in a high concentration on the surface (S) or surface layer (Ls) of the molten aluminum (M) when the molten aluminum (M) is in a bare state. The standard collection time is not particularly limited and may be determined according to the concentration of the alkaline light metal contained in the molten aluminum (M), the depth of the molten aluminum (M), etc.

[0062] As described above, when alkaline light metals are concentrated in a high concentration on the surface (S) or surface layer (Ls) of molten aluminum (M), and an alkaline light metal removal flux (F2) is sprayed on the surface (S) of the molten aluminum (M), the alkaline light metal and the alkaline light metal removal flux (F2) can be smoothly brought into contact and reacted, thereby improving the alkaline light metal removal efficiency using the alkaline light metal removal flux (F2).

[0063] As described above, the alkaline light metal removal flux (F2) is supplied by the alkaline light metal removal flux supply unit (30) described above, but is not limited thereto. That is, the alkaline light metal removal flux (F2) may be supplied by using a device or method other than the alkaline light metal removal flux supply unit (30), such as by injecting the alkaline light metal removal flux (F2) onto the surface (S) of the molten aluminum (M) using an external work vehicle (e.g., a shovel), or by injecting a synthetic resin bag (e.g., a PE bag) containing the alkaline light metal removal flux (F2) onto the surface (S) of the molten aluminum (M).

[0064] Meanwhile, if a dead space occurs on the surface (S) of the molten aluminum (M) where the alkaline light metal removal flux (F2) is not distributed, the efficiency of removing alkaline light metals using the alkaline light metal removal flux (F2) may be reduced. To solve this, the alkaline light metal removal device (1) contained in the molten aluminum (M) may further include a flattening unit (50) capable of flattening the alkaline light metal removal flux (F2) sprayed on the surface (S) of the molten aluminum (M) so that the alkaline light metal removal flux (F2) is evenly distributed over the entire area of ​​the surface (S) of the molten aluminum (M).

[0065] The structure of the flattening unit (50) is not particularly limited. For example, as illustrated in Fig. 7, the flattening unit (50) may be configured to flatten the surface (S) of the molten aluminum (M) by pushing or pulling the alkaline light metal removing flux (F2) sprayed on it.

[0066] As illustrated in Fig. 8, the flattening unit (50) can flatten the alkaline light metal removal flux (F2) sprayed on the surface (S) of the molten aluminum (M) and evenly distribute it on the surface (S) of the molten aluminum (M), thereby further improving the efficiency of removing alkaline light metals using the alkaline light metal removal flux (F2).

[0067] The composition of the flux (F2) for removing alkaline light metals is not particularly limited. For example, the flux (F2) for removing alkaline light metals may contain chloride, fluoride, etc.

[0068] Chloride has the function of removing alkaline light metals contained in molten aluminum (M) through its high reactivity with alkaline light metals. The type of compound that can be used as a chloride in the flux (F2) for removing alkaline light metals is not particularly limited, and by utilizing the principle that the reaction proceeds toward a lower halogenation energy (△Go), a compound having a lower halogenation energy than lithium chloride (LiCl) or sodium chloride (NaCl) can be applied as a chloride in the flux (F2) for removing alkaline light metals so as to remove alkaline light metals contained in the molten aluminum (M). For example, the chloride may be any one selected from the group consisting of MgCl2, KCl, or a mixture thereof.

[0069] Fluoride has the function of controlling the reaction rate between chloride and sodium, thereby facilitating a continuous reaction. The type of compound that can be used as a fluoride in a flux (F2) for removing alkaline light metals is not particularly limited. For example, the fluoride may be KAlF4.

[0070] The content ratio of the above-mentioned chloride and fluoride is not particularly limited. For example, the flux (F2) for removing alkaline light metals may contain 95 to 100 wt% of chloride and 0 to 5 wt% of fluoride. More preferably, the flux (F2) for removing alkaline light metals may contain 40 to 60 wt% of MgCl2, 40 to 60 wt% of KCl, and 0 to 5 wt% of KAlF4.

[0071] The supply operation and the flattening operation of the alkaline light metal removal flux (F2) using the aforementioned alkaline light metal removal flux supply unit (30) and the flattening unit (50) are preferably performed in a state where the temperature of the aluminum molten metal (M) is maintained above a predetermined reference temperature by a heating device (not shown) installed in the aluminum melting furnace (2) so that the reaction efficiency of the alkaline light metal and the alkaline light metal removal flux (F2) can be improved. For example, the reference temperature may be 730°C.

[0072] FIG. 9 and FIG. 10 are drawings showing the reaction between the alkaline light metal and the alkaline light metal removing flux as the surface layer of the molten aluminum is mixed with the alkaline light metal removing flux by the stirring unit of FIG. 1.

[0073] Next, the stirring unit (40) is a device that stirs the flux (F2) for removing alkaline light metals and the surface layer (Ls) of the aluminum molten metal (M) so that they are mixed with each other.

[0074] The structure of the stirring unit (40) is not particularly limited. For example, as illustrated in FIG. 9, the stirring unit (40) may be provided so as to repeatedly push and pull the alkaline light metal removing flux (F2) distributed on the surface (S) of the molten aluminum (M) and the surface layer (Ls) of the molten aluminum (M) in the front-back horizontal direction, or to repeatedly tap the alkaline light metal removing flux (F2) distributed on the surface (S) of the molten aluminum (M) toward the surface layer (Ls) of the molten aluminum (M) to stir the alkaline light metal removing flux (F2) and the surface layer (Ls) of the molten aluminum (M).

[0075] The stirring operation using the stirring unit (40) is preferably performed for a time longer than a predetermined standard stirring time while the temperature of the molten aluminum (M) is maintained at a predetermined reference temperature or higher by the heating device so that the surface layer (L s) of the molten aluminum (M) and the flux (F2) for removing alkaline light metals can be evenly mixed with each other. For example, the reference temperature may be 730°C, and the reference stirring time may be 30 minutes.

[0076] As illustrated in Fig. 10, by the stirring operation using the stirring unit (40), sodium (Na) and / or lithium (Li) collected at a high concentration on the surface (S) or surface layer (Ls) of the molten aluminum (M) react with the flux (F2) for removing alkaline light metals to generate sodium chloride (NaCl) and / or lithium chloride (LiCl), through which sodium and / or lithium can be removed from the molten aluminum (M). In addition, sodium chloride or lithium chloride coagulates with the flux (F2) for removing alkaline light metals to form dross (not shown). In this way, the dross formed during the alkaline light metal removal process has a lower specific gravity than aluminum, and thus floats on the surface (S) of the molten aluminum (M). Accordingly, by using the aforementioned dross recovery unit (20) or another device, the dross formed in the alkaline light metal removal process can be recovered from the surface (S) of the aluminum molten metal (M), thereby making the aluminum molten metal (M) into a bare state.

[0077] FIG. 11 is a flowchart for explaining a method for removing alkaline light metals contained in molten aluminum using an alkaline light metal removal device shown in FIG. 1.

[0078] Referring to FIG. 11, a method for removing alkaline light metals contained in molten aluminum (M) using an alkaline light metal removal device (1) may include a step (S10) of making the molten aluminum (M) into a bare state, a step (S20) of floating the alkaline light metals contained in the molten aluminum (M) using the difference in specific gravity between aluminum and the alkaline light metals and collecting them on the surface (S) or surface layer (Ls) of the molten aluminum (M), a step (S30) of supplying a flux (F2) for removing alkaline light metals to the surface (S) of the molten aluminum (M), and a step (S40) of stirring the surface layer (Ls) of the molten aluminum (M) and the flux (F2) for removing alkaline light metals from the molten aluminum (M) using the flux (F2) for removing alkaline light metals.

[0079] First, in step S 10, the dross (D1) generated during the melting process of aluminum is treated using a dross treatment flux (F1) and then recovered to make the aluminum molten metal (M) into a bare state.

[0080] This S 10 step may include a step (S 12) of supplying (e.g., spraying) a dross-processing flux (F1) to the dross (D1) floating on the surface (S) of the aluminum molten metal (M) using a dross-processing flux supply unit (10) to process the dross (D1) using the dross-processing flux (F1), and a step (S 14) of recovering black dross (D2) formed by treating the dross (D1) with the dross-processing flux (F1) using a dross recovery unit (20) to make the aluminum molten metal (M) into a bare state.

[0081] Next, in step S 20, the aluminum molten metal (M) that has become a molten state in step S 10 is allowed to stand in a calm state for a predetermined standard collection time until the alkaline light metal contained in the molten aluminum (M) is floated by the specific gravity difference and is collected on the surface (S) or surface layer (Ls) of the aluminum molten metal (M) and is distributed in a high concentration on the surface (S) or surface layer (Ls) of the aluminum molten metal (M).

[0082] Afterwards, in step S 30, in a state where alkaline light metals are distributed in high concentration on the surface (S) or surface layer (Ls) of the aluminum molten metal (M) in step S 20, a flux (F2) for removing alkaline light metals is sprayed on the surface (S) of the aluminum molten metal (M).

[0083] This S 30 step may include a step (S 32) of spraying an alkaline light metal removal flux (F2) onto the surface (S) of the aluminum molten metal (M) using an alkaline light metal removal flux supply unit (30), and a step (S 34) of flattening the alkaline light metal removal flux (F2) sprayed in step S 32 using a flattening unit (50) to evenly distribute it over the entire area of ​​the surface (S) of the aluminum molten metal (M).

[0084] Next, in step S 40, the alkaline light metal removal flux (F2) sprayed on the surface (S) of the molten aluminum (M) in step S 30 and the surface layer (Ls) of the molten aluminum (M) on which the alkaline light metal is distributed at a high concentration are stirred to mix with each other, thereby removing the alkaline light metal from the molten aluminum (M) using the alkaline light metal removal flux (F2).

[0085] This S 40 step may include a step (S 32) of stirring the surface layer (Ls) of the aluminum molten metal (M) and the alkaline light metal removing flux (F2) by repeatedly pushing and pulling the alkaline light metal removing flux (F2) distributed on the surface (S) of the aluminum molten metal (M) and the surface layer (Ls) of the aluminum molten metal (M) in a horizontal direction back and forth using a stirring unit (40) or by repeatedly striking the alkaline light metal removing flux (F2) distributed on the surface (S) of the aluminum molten metal (M) toward the surface layer (Ls) of the aluminum molten metal (M), and a step (S 34) of recovering the dross generated when the alkaline light metal is removed by the alkaline light metal removing flux (F2) from the aluminum molten metal (M) using a dross recovery unit (20) or another device.

[0086] The above description is merely an illustrative illustration of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

[0087] <Explanation of symbols>

[0088] 1: Device for removing alkaline light metals contained in molten aluminum

[0089] 2: Aluminum melting furnace

[0090] 10: Flux supply unit for dross processing

[0091] 20: Dross Recovery Unit

[0092] 30: Flux supply unit for alkaline light metal removal

[0093] 40: Stirring unit

[0094] 50: Flattening Unit

[0095] M: molten aluminum

[0096] D1: Dross

[0097] F1: Flux for dross treatment

[0098] D2: Black Dross

[0099] F2: Flux for removing alkaline light metals

Claims

1. An alkaline light metal removal flux supply unit that supplies an alkaline light metal removal flux to the surface of the aluminum molten metal while the alkaline light metal contained in the aluminum molten metal is floated using the difference in specific gravity between the aluminum and the alkaline light metal and collected on the surface or superficial layer of the aluminum molten metal; and An alkaline metal removal device contained in an aluminum molten metal, comprising a stirring unit that stirs a surface layer of the aluminum molten metal and the alkaline metal removal flux so that the alkaline metal is removed from the aluminum molten metal by a reaction between the alkaline metal and the alkaline metal removal flux.

2. In paragraph 1, A device for removing alkaline light metals contained in molten aluminum, wherein the alkaline light metals include at least one of lithium and sodium.

3. In paragraph 1, A dross treatment flux supply unit that supplies dross treatment flux to the dross floating on the surface of the molten aluminum; and The above dross further includes a dross recovery unit that recovers black dross formed by treating the above dross with the dross treatment flux, thereby making the aluminum molten metal into a bare state. The above-mentioned alkaline light metal removal flux supply unit is an alkaline light metal removal device contained in an aluminum molten metal, which supplies the alkaline light metal removal flux after the aluminum molten metal is in a calm state for a predetermined standard collection time until the alkaline light metal is collected on the surface or superficial layer of the aluminum molten metal due to the specific gravity difference while the aluminum molten metal is in the bare state.

4. In paragraph 3, The above flux for dross treatment is an alkaline light metal removal device contained in molten aluminum, containing 35 wt% of NaCl, 25 wt% of KCl, 15 wt% of AlF3, 5 wt% of KAlF4, 10 wt% of NaNO3, and 10 wt% of Na2SO4.

5. In paragraph 1, It further includes a flattening unit that flattens the alkaline light metal removal flux distributed on the surface of the aluminum molten metal by the alkaline light metal removal flux supply unit, The above stirring unit is an alkaline metal removal device contained in an aluminum molten metal, which stirs the surface layer of the aluminum molten metal and the alkaline metal removal flux while the alkaline metal removal flux is flattened.

6. In paragraph 1, The above stirring unit is a device for removing alkaline metals contained in an aluminum molten metal, which repeatedly pushes and pulls the alkaline metal removal flux distributed on the surface of the aluminum molten metal and the surface layer of the aluminum molten metal in a horizontal direction forward and backward or repeatedly taps the alkaline metal removal flux distributed on the surface of the aluminum molten metal toward the surface layer of the aluminum molten metal to stir the surface layer of the aluminum molten metal and the alkaline metal removal flux.

7. In paragraph 1, A method for removing alkaline light metals contained in molten aluminum, wherein the above-mentioned alkaline light metal removal flux contains 40 to 60 wt% of MgCl2, 40 to 60 wt% of KCl, and 0 to 5 wt% of KAlF4. 8.(A) A step of collecting alkaline light metals contained in molten aluminum on the surface or superficial layer of the molten aluminum by using the difference in specific gravity between aluminum and alkaline light metals; (B) a step of supplying a flux for removing alkaline light metals to the surface of the molten aluminum; and (C) A method for removing alkaline metals contained in molten aluminum, comprising a step of stirring the surface layer of the molten aluminum and the alkaline metal removal flux, and removing the alkaline metals from the molten aluminum using the alkaline metal removal flux.

9. In paragraph 8, A method for removing alkaline light metals contained in molten aluminum, wherein the alkaline light metals include at least one of lithium and sodium.

10. In paragraph 8, In the above step (A), a method for removing alkaline light metals contained in an aluminum molten metal is provided, wherein the aluminum molten metal is allowed to stand in a calm state for a predetermined standard collection time until the alkaline light metal floats due to the specific gravity difference and gathers on the surface or superficial layer of the aluminum molten metal.

11. In paragraph 8, (D) A method for removing alkaline light metals contained in molten aluminum, which is performed before step (A) and further includes a step of making the molten aluminum into a bare state.

12. In paragraph 11, Step (D) above, (d1) a step of supplying a flux for dross treatment to the dross floating on the surface of the molten aluminum; and (d2) A method for removing alkaline light metals contained in molten aluminum, comprising the step of recovering black dross formed by treating the dross with the dross treatment flux from the surface of the molten aluminum, thereby making the molten aluminum into the bare state.

13. In paragraph 12, The above dross treatment flux is a method for removing alkaline light metals contained in molten aluminum, containing 35 wt% of NaCl, 25 wt% of KCl, 15 wt% of AlF3, 5 wt% of KAlF4, 10 wt% of NaNO3, and 10 wt% of Na2SO4.

14. In paragraph 8, Step (B) above, (b1) a step of spraying the above alkaline light metal removal flux onto the surface of the aluminum molten metal; and (b2) A method for removing alkaline light metals contained in molten aluminum, comprising a step of flattening the alkaline light metal removal flux sprayed in step (b1).

15. In paragraph 8, In the step (C), a method for removing alkaline metals contained in an aluminum molten metal, wherein the alkaline metal removal flux distributed on the surface of the aluminum molten metal and the surface layer of the aluminum molten metal are repeatedly pushed and pulled in a horizontal direction forward and backward, or the alkaline metal removal flux distributed on the surface of the aluminum molten metal is repeatedly struck toward the surface layer of the aluminum molten metal to mix the surface layer of the aluminum molten metal and the alkaline metal removal flux.

16. In paragraph 8, A method for removing alkaline light metals contained in molten aluminum, wherein the above-mentioned alkaline light metal removal flux contains 40 to 60 wt% of MgCl2, 40 to 60 wt% of KCl, and 0 to 5 wt% of KAlF4.

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