KR101978141B1 - Appratus for producing aluminum-scandium alloy and method using the same - Google Patents

Abstract

The present invention relates to an apparatus for manufacturing an aluminum-scandium alloy, which comprises: an electrolytic bath in which an electrolyte is stored for electrolysis, and a through hole is formed at one side of a floor surface; an anode provided to be immersed in the electrolytic bath, and provided to be spaced from a side surface of the electrolytic bath; a cathode having aluminum arranged on the floor surface of the electrolytic bath; and a stopper member opening and closing the through hole. According to the present invention, in a method for manufacturing an aluminum-scandium alloy by using an electrolytic method, semi-continuous or continuous production can be possible to improve productivity, and further, production costs are reduced to extend a scandium market.

Description

[0001] APPARATUS FOR PRODUCING ALUMINUM-SCANDIUM ALLOY AND METHOD USING THE SAME [0002]

The present invention relates to an apparatus and a method for manufacturing an aluminum-scandium alloy.

Rare earths are an essential resource used in various fields such as magnets, phosphors, catalysts, and abrasives. China accounts for most of the world's exports. In 2010, China and Japan collided with SENKAKU, which restricted China's export of rare earths In 2011, the price of some rare earths surged more than five times.

Japan imports rare earths as a first processed product and then processes it as raw material for the high-tech products and exports it to Korea. In Korea, the technology development for the separation of high-value-added rare earths, Is required.

Scandium (Sc, Scandium) No. 21 classified as a pseudo rare earth element is an alloy element added to a small amount of aluminum (Al, Aluminum) alloy. When a small amount of scandium is added to an aluminum alloy, the mechanical properties, Corrosion resistance and elongation of the steel sheet.

Such scandium metal reduction techniques are disclosed in patents such as EP0238185, JP2600282, and JP5094031, all based on the metallothermic reduction method. On the other hand, Professor Okabe's team at Tokyo University recently presented a process for manufacturing scandium-containing aluminum alloys through electrolysis (http://www.okabe.iis.utokyo.ac.jp/core-to-core/rmw/RMW3 /slide/RMW3_20_Harata_T.pdf).

In the case of the electrolysis method, the target metal to be reduced in the cathode is obtained by the electrochemical reaction of the cathode and the anode in the molten salt state, and the carbon dioxide or chlorine gas is generated in the anode. The main characteristics of the electrolysis process proposed by Prof. Okabe are scandium oxide (Sc2O3, Scandia) as the raw material, eutectic salt of CaCl ₂ -Sc ₂ O ₃ as the electrolyte, and 900 The electrolysis process proceeds at the process temperature.

The content of scandium in the aluminum-scandium alloy prepared by the above-described conventional technique is about 2 wt%, and it is used as a master alloy to prepare a desired amount of aluminum-scandium alloy by mixing a certain amount with aluminum.

However, in the molten salt electrolysis process, there is a limitation in using the structural material because the process is performed at a high temperature (800 to 1,100 ° C.), and since a fluoride-based mixed salt having high erosion resistance to refractory and metal components is used, There is a problem in that the mother alloy is produced in the form of the alloy.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an apparatus and method for manufacturing and recovering aluminum-scandium alloy in semi continuous or continuous manner.

According to an aspect of the present invention, there is provided an electrolytic cell comprising: an electrolytic cell storing an electrolyte for electrolysis and having a through hole formed on at least one side of a bottom surface thereof; A cathode provided so as to be immersed in the electrolytic bath, the anode being provided apart from the side of the electrolytic bath; An anode including aluminum disposed on a bottom surface of the electrolytic cell; And a stopper member for opening and closing the through-hole.

And a control device for moving the stopper member up and down.

The stopper member may be made of at least one selected from the group consisting of titanium, platinum and tantalum.

And a reservoir formed on the outer side of the through hole and through which the molten alloy discharged from the through hole is recovered.

The reservoir may further comprise a measuring member for measuring the weight of the molten alloy.

The electrolyte may be a fluoride, a chloride, or a mixture thereof.

The fluoride may be selected from the group consisting of sodium hexafluoroaluminate (Na ₃ AlF ₆ ), potassium hexafluoroaluminate (K ₃ AlF ₆ ), aluminum fluoride (AlF ₃ ), calcium fluoride (CaF ₂ ), sodium fluoride ), Potassium fluorofluoride (KF), potassium bromofluoride (KBrF ₄ ), potassium fluoride (KHF ₂ ), calcium hexafluorophosphate (KPF ₆ ), potassium hexafluorosilicate (K ₂ SiF ₆ ) , Lithium hexafluoroaluminate (Li ₃ AlF ₆ ), ammonium hexafluoroaluminate ((NH ₄ ) ₃ AlF ₆ ), and potassium fluorophosphate (KPO ₂ F ₂ ).

The chloride may be at least one selected from lithium chloride (LiCl), potassium chloride (KCl), chromium chloride (CrCl ₂ ), calcium chloride (CaCl ₂ ) and bromine chloride (BrCl).

The anode may be at least one selected from carbon, iron and nickel.

According to another aspect of the present invention, there is provided a method of manufacturing an electrolytic cell, comprising the steps of: injecting electrolytes, aluminum oxide and scandium oxide into an electrolytic cell including a through hole at least on one side of a bottom surface and including a stopper member for opening and closing the through hole; An obtaining step of obtaining an aluminum-scandium alloy by applying an electric current to the electrolytic cell and performing electrolysis; A recovery step of cutting off the current and moving the stopper member to recover the aluminum-scandium alloy through the through hole to the storage tank; And a sealing step of sealing the through hole by moving the stopper member.

The aluminum-scandium alloy recovered in the recovering step may be 75 to 85 wt% of the weight of aluminum initially charged.

After the step of sealing the through-hole, aluminum oxide and scandium oxide may be further added to the electrolytic bath, and the aluminum-scandium alloy including the obtaining step, the recovering step and the sealing step may be repeated twice or more.

The aluminum oxide may be firstly charged and then the scandium oxide may be introduced.

The further added aluminum oxide may be 93 to 98% by weight of the recovered aluminum-scandium alloy.

The further added scandium oxide may be 2 to 7 wt% of the recovered aluminum-scandium alloy.

According to the present invention, in the method of producing an aluminum-scandium alloy by using an electrolysis method, quasi-continuous or continuous production is enabled, productivity is improved, and scandium market is expected to expand through reduction of production cost.

Fig. 1 schematically shows an electrolytic apparatus used in the production of a conventional aluminum-scandium alloy.
2 is a top view (a) and a front view (b) of an aluminum-scandium alloy manufacturing apparatus according to an embodiment of the present invention.
3 schematically shows a stopper member and a control device according to an embodiment of the present invention.
FIGS. 4 and 5 schematically illustrate a method for manufacturing an aluminum-scandium alloy according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to various embodiments. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to an apparatus and a method for manufacturing an aluminum-scandium alloy.

Fig. 1 schematically shows an electrolytic apparatus conventionally used for producing an aluminum-scandium alloy. 1, the electrolytic apparatus includes an electrolytic bath main body filled with an electrolyte including a molten salt, a cathode partially or entirely disposed in the electrolytic bath body, and a cathode including aluminum disposed on the bottom of the electrolytic bath body consist of.

Since the molten salt electrolytic process described above is performed at a high temperature (800 to 1,100 ° C.), there is a limitation in using the structural material, and since a fluoride-based mixed salt having high erosion resistance to refractory and metal components is used, batch type), which is disadvantageous in terms of productivity and cost.

The present inventors have completed the present invention by focusing on an apparatus and a method for producing an aluminum-scandium alloy by a semi-continuous or continuous production method using an electrolysis method in order to solve the above problems. 2 is a schematic view of an apparatus for manufacturing an aluminum-scandium alloy according to an embodiment of the present invention. FIG. 2 (a) is a top view and FIG. 2 (b) is a front view. .

According to an aspect of the present invention, there is provided an electrolytic cell comprising: an electrolytic cell storing an electrolyte for electrolysis and having a through hole formed on at least one side of a bottom surface thereof; A cathode provided so as to be immersed in the electrolytic bath, the anode being provided apart from the side of the electrolytic bath; An anode including aluminum disposed on a bottom surface of the electrolytic cell; And a stopper member for opening and closing the through-hole.

The electrolytic bath of the present invention may be formed of a conductive material, and an accommodation space in which an electrolyte is stored may be formed. The material of the electrolytic bath is not particularly limited, but may be made of stainless steel, tungsten, or the like. Also, the shape of the electrolytic bath may be various shapes such as a circle, a square, and the like.

An electrolytic solution for electrolysis is stored in the electrolytic bath. The electrolyte is not particularly limited as long as it is an electrolyte used in an electrolytic bath in which an aluminum-scandium alloy is electrolytically deposited. For example, it may be a fluoride, a chloride or a mixture thereof.

The fluoride may be selected from the group consisting of sodium hexafluoroaluminate (Na ₃ AlF ₆ ), potassium hexafluoroaluminate (K ₃ AlF ₆ ), aluminum fluoride (AlF ₃ ), calcium fluoride (CaF ₂ ), sodium fluoride ), Potassium fluorofluoride (KF), potassium bromofluoride (KBrF ₄ ), potassium fluoride (KHF ₂ ), calcium hexafluorophosphate (KPF ₆ ), potassium hexafluorosilicate (K ₂ SiF ₆ ) , Lithium hexafluoroaluminate (Li ₃ AlF ₆ ), ammonium hexafluoroaluminate ((NH ₄ ) ₃ AlF ₆ ), and potassium fluorophosphate (KPO ₂ F ₂ ). On the other hand, the chloride may be at least one selected from lithium chloride (LiCl), potassium chloride (KCl), chromium chloride (CrCl ₂ ), calcium chloride (CaCl ₂ ) and bromine chloride

On the other hand, the electrolytic process in which the aluminum-scandium alloy is electrolytically deposited proceeds at an elevated temperature of 700 or more, so that the electrolyte and aluminum contained in the electrolytic bath are in a molten state. Therefore, aluminum included in the cathode of the present invention may be in a liquid state.

Some or all of the anode included in the aluminum-scandium alloy manufacturing apparatus according to the present invention may be disposed in the electrolytic bath body, and further, a part thereof may be impregnated in the electrolyte. The positive electrode is not particularly limited as long as it is an inert electrode that does not dissolve in the molten salt. For example, the positive electrode may include at least one selected from among carbon (C), iron (Fe), and nickel (Ni) Is more preferable. When the carbon electrode is used as the anode, the shape and the number of the electrode are not particularly limited.

An apparatus for manufacturing an aluminum-scandium alloy according to an aspect of the present invention includes a through hole formed at one side of a bottom surface of an electrolytic bath, and the through hole is opened and closed by a stopper member.

FIG. 3 schematically shows a stopper member according to an embodiment of the present invention, and may include a head portion inserted into a through hole formed in an electrolytic bath and a body portion connected to the head portion. The size of the head portion can be freely selected within a range that does not cause interference with the electrolytic reaction region in the electrolytic cell, but is preferably a structure in which the head portion is completely inserted into the through hole and closely contacted. As described later, when complete adhesion is not achieved, molten aluminum and molten salt existing in the electrolytic bath may leak to the outside.

On the other hand, although the head part and the body part can be joined by a method such as welding, there is a problem that the joint part is weak and may be broken.

Further, the present invention may further comprise a control device for moving the stopper member up and down, and the control device is connected to the upper portion of the body portion of the stopper member and, if necessary, serves to move the stopper member up and down .

On the other hand, the stopper member is preferably made of a material having a high melting point, a high electrical resistance, and a high reactivity with a fluoride-based mixed molten salt at a high temperature (800 to 1,100 ° C). Accordingly, platinum, tantalum, titanium, or the like can be used, and titanium is more preferably used.

If a carbon steel or stainless steel plate is used, elements such as Fe, Ni, and Cr participate in the electrolysis reaction and act as impurities. When a material having low electrical resistance is used, When the member is connected, the stopper member is also charged to the negative electrode to lower the current efficiency used for electrolysis, which is not preferable.

Meanwhile, the apparatus for manufacturing an aluminum-scandium alloy according to an embodiment of the present invention may further include a reservoir formed on the outer side of the through-hole and through which the molten alloy discharged from the through-hole is recovered. More specifically, the through hole is opened after the electrolysis process, so that the molten aluminum-scandium alloy flows out into the reservoir.

The reservoir may further include a measuring member for measuring the weight of the molten alloy. The weight of the alloy in the measuring member can be measured to determine the amount of aluminum or scandium alloy to be added, as described later.

FIGS. 4 and 5 schematically illustrate a method for manufacturing an aluminum-scandium alloy according to an embodiment of the present invention. Hereinafter, with reference to FIGS. 4 and 5, a method of manufacturing an aluminum-scandium alloy using the above-described aluminum-scandium alloy manufacturing apparatus will be described in detail.

According to another aspect of the present invention, there is provided a method of manufacturing an electrolytic cell, comprising the steps of: injecting electrolytes, aluminum oxide and scandium oxide into an electrolytic cell having a through hole formed on at least one side of a bottom surface thereof and including a stopper member for opening and closing the through hole; An obtaining step of obtaining an aluminum-scandium alloy by applying an electric current to the electrolytic cell and performing electrolysis; A recovery step of cutting off the current and moving the stopper member to recover the aluminum-scandium alloy through the through hole to the storage tank; And a sealing step of sealing the through hole by moving the stopper member.

In one embodiment of the present invention, the electrolysis process may be a Hall-Heroult process, which is a conventional aluminum electrolysis process. For example, the hole-etch process is a process in which a molten salt is used as an electrolyte, a carbon material is used as an anode, and an aluminum liquid is used as a cathode. In such a hole-etch process, aluminum is dissolved in the salt of the molten salt, aluminum is obtained at the cathode due to the introduction of a strong direct current and the electrochemical reaction at the anode and cathode at a high temperature.

Further, the present invention can be supplied to an electrolytic cell of an electrolysis process using a molten salt containing a fluoride, a chloride or a mixture thereof as an electrolyte. By using this as an electrolyte, the solubility of scandium oxide introduced into the electrolytic bath as a reaction raw material can be increased to increase the productivity of the aluminum-scandium alloy.

After the electrolyte is injected into the electrolytic cell, aluminum oxide and scandium oxide, which are the raw materials of the reaction, are charged, and an electrolysis process is performed by applying an electric current to the electrolytic bath, an aluminum-scandium alloy can be obtained from the cathode.

The electrolysis process is preferably performed in a temperature range of 900 to 1300 DEG C, and if the process temperature is less than 900 DEG C, the salt is not dissolved and it is difficult to perform the electrolysis process. If the process temperature is higher than 1300 DEG C, It is uneconomical because of the increased energy cost.

The electrolysis process should be performed in a process voltage range in which aluminum oxide and scandium oxide are decomposed. The applied voltage range is preferably 0 to 3.0 V, more preferably 2.0 to 2.5 V. Therefore, when the applied voltage is less than 2.0 V, scandium does not substantially reduce. When the applied voltage exceeds 3.0 V, impurities other than aluminum and scandium are reduced together in the electrolytic bath, so that it is difficult to obtain a pure aluminum-scandium alloy.

Through the above process, the aluminum-scandium alloy is obtained and the current is cut off. Then, when the stopper member is slowly moved upward through the control device, the molten aluminum-scandium alloy flows through the through hole in the bottom surface of the electrolytic bath to the reservoir located outside the electrolytic bath and is recovered.

At this time, since the storage tank for storing the aluminum-scandium alloy in the molten state is provided with the measuring member capable of measuring the weight, for example, the balance, the amount of the aluminum-scandium alloy to be recovered can be adjusted. When the desired amount of aluminum-scandium alloy is recovered, the stopper member is moved back down through the control device to be sealed by being brought into close contact with the through-hole. As described above, it is preferable to appropriately adjust the stopper movement speed in order to recover or discharge the aluminum-scandium alloy in a molten state by a desired weight in operating the stopper member up and down, and the shape of the recovered aluminum-scandium alloy is obtained Various shapes can be obtained by making the mold according to the shape of the alloy to be shaped.

Meanwhile, it is preferable that the amount of the aluminum-scandium alloy recovered in the recovery step is 75 to 85 wt% of the weight of aluminum oxide initially added. If it exceeds 85% of the weight of the initially charged aluminum oxide, it may be disadvantageous to increase the processing time because a part of the molten salt flows together and the molten salt needs to be replenished. If it is less than 75%, the aluminum- It is possible to cause a problem of lowering the productivity

The present invention is characterized in that after the step of sealing the through-hole, the aluminum-scandium oxide is further added to the electrolytic bath and the aluminum-scandium alloy is formed by repeating the above-mentioned step of obtaining, The scandium alloy can be produced continuously or continuously.

More specifically, since the initially charged aluminum oxide and scandium oxide are consumed in producing the alloy, aluminum oxide corresponding to 93 to 98% by weight of the recovered alloy and scandium oxide corresponding to 2 to 7% by weight of the recovered alloy weight Is fed through the upper part of the electrolytic bath

In this case, it is more preferable to inject scandium oxide after the aluminum oxide is firstly introduced and completely melted, so that the molten salt and the molten aluminum are separated by the difference in specific gravity, so that they can be separated more quickly.

The aluminum-scandium alloy can be produced continuously or continuously by repeating the series of the above-described aluminum-scandium alloy manufacturing process several times or more.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples are intended to further illustrate the present invention and are not intended to limit the present invention.

Example

The aluminum-scandium alloy manufacturing process was performed twice in succession using a titanium stopper member as an apparatus for manufacturing an aluminum-scandium alloy according to an embodiment of the present invention. The compositional analysis results of the recovered aluminum-scandium alloy are shown in Table 1 below.

Unit (wt%) Li Na Al Ca Fe Sc Primary aluminum-scandium alloy 0.097 0.73 Honey. 0.037 0.088 2.38 Secondary aluminum-scandium alloy 0.049 0.54 Honey. 0.026 0.077 5.63

Comparative Example 1

An aluminum-scandium alloy was prepared in the same manner as in the above example, except that a stainless steel 304L steel stopper was used as a stopper member and an aluminum-scandium alloy was once produced. The compositional analysis results of the recovered aluminum-scandium alloy are shown in Table 2 below.

Unit (wt%) Li Na Al Ca Fe Ni Sc  Aluminum-scandium alloy 0.031 0.068 Honey. 0.020 1.8 0.12 2.5

Comparative Example 2

An aluminum-scandium alloy was prepared in the same manner as in the above example, except that a stainless steel 316L steel stopper was used as the stopper member and the aluminum-scandium alloy was once produced. The analysis results of the components in the recovered aluminum-scandium alloy are shown in Table 3 below.

Unit (wt%) Li Na Al Ca Fe Ni Sc  Aluminum-scandium alloy 0.009 0.011 Honey. 0.005 2.2 0.13 3.7

Referring to Table 1, according to the embodiment of the present invention, the scandium content is 2 wt% or more, and the aluminum alloy is recovered, and the content of Fe and other components is low. On the other hand, as shown in Tables 2 and 3, in the case of Comparative Examples 1 and 2, Fe, Ni and the like, which are major components of stainless steel, are high and can be confirmed to act as impurities.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

100: electrolytic bath
120: anode
140: cathode
160: Stopper member
180: electrolyte
200: by-product gas
220: Control device
240: Storage tank
260: Measurement member
280: Through hole

Claims (15)

An electrolytic cell storing an electrolyte for electrolysis and having a through hole formed on at least one side of a bottom surface thereof;
A cathode provided so as to be immersed in the electrolytic bath, the anode being provided apart from the side of the electrolytic bath;
An anode including aluminum disposed on a bottom surface of the electrolytic cell; And
And a stopper member for opening and closing the through hole,
Wherein the stopper member is made of at least one selected from the group consisting of titanium, platinum and tantalum.
The method according to claim 1,
Further comprising a control device for moving the stopper member up and down.
delete The method according to claim 1,
Further comprising a reservoir formed on the outside of the through-hole and through which the molten alloy discharged from the through-hole is recovered.
5. The method of claim 4,
Wherein the reservoir further comprises a measuring member for measuring the weight of the alloy in the molten state.
The method according to claim 1,
Wherein the electrolyte is a fluoride, a chloride, or a mixture thereof.
The method according to claim 6,
The fluoride may be selected from the group consisting of sodium hexafluoroaluminate (Na ₃ AlF ₆ ), potassium hexafluoroaluminate (K ₃ AlF ₆ ), aluminum fluoride (AlF ₃ ), calcium fluoride (CaF ₂ ), sodium fluoride ), Potassium fluorofluoride (KF), potassium bromofluoride (KBrF ₄ ), potassium fluoride (KHF ₂ ), calcium hexafluorophosphate (KPF ₆ ), potassium hexafluorosilicate (K ₂ SiF ₆ ) Characterized in that it is at least one selected from lithium hexafluoroaluminate (Li ₃ AlF ₆ ), ammonium hexafluoroaluminate ((NH ₄ ) ₃ AlF ₆ ) and potassium fluorophosphate (KPO ₂ F ₂ ) Scandium alloy manufacturing equipment.
The method according to claim 6,
Wherein the chloride is at least one selected from the group consisting of lithium chloride (LiCl), potassium chloride (KCl), chromium chloride (CrCl ₂ ), calcium chloride (CaCl ₂ ) and bromine chloride (BrCl).
The method according to claim 1,
Wherein the anode comprises at least one selected from carbon, iron and nickel.
Introducing an electrolyte, aluminum oxide, and scandium oxide into an electrolytic cell including a through-hole formed on at least one side of a bottom surface and including a stopper member for opening and closing the through-hole;
An obtaining step of obtaining an aluminum-scandium alloy by applying an electric current to the electrolytic cell and performing electrolysis;
A recovery step of cutting off the current and moving the stopper member to recover the aluminum-scandium alloy through the through hole to the storage tank; And
And a sealing step of sealing the through hole by moving the stopper member,
Wherein the stopper member is made of at least one selected from the group consisting of titanium, platinum and tantalum.
11. The method of claim 10,
Wherein the aluminum-scandium alloy recovered in the recovering step is 75 to 85 wt% of the weight of the initially charged aluminum oxide.
11. The method of claim 10,
Wherein the step of sealing the through hole further comprises the step of further adding aluminum oxide and scandium oxide to the electrolytic bath and repeating the aluminum-scandium alloy production comprising the obtaining step, the recovering step and the sealing step at least twice. A method of manufacturing a scandium alloy.
13. The method of claim 12,
Wherein the aluminum oxide is firstly introduced and then scandium oxide is introduced.
The method of claim 12, wherein
Wherein the further added aluminum oxide is from 93 to 98% by weight of the recovered aluminum-scandium alloy.
13. The method of claim 12,
Wherein the additional scandium oxide is 2 to 7 wt% of the recovered aluminum-scandium alloy.

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