Device and method for preparing aluminum-rare earth alloy by floating irregular cathode molten salt electrolysis

Abstract

The application provides a device for preparing aluminum-rare earth alloy by molten salt electrolysis, comprising an electrolytic tank body, an insulating material inner wall arranged on the inner wall of the electrolytic tank body, no insulating material inner wall arranged on the inner wall of the lower part of the electrolytic tank body, a cathode and an anode arranged in the electrolytic tank, and a groove arranged at the bottom of the cathode. The device and method for preparing aluminum-rare earth alloy by molten salt electrolysis of the floating special-shaped cathode can avoid the precipitation of oxides, realize the continuous addition of aluminum liquid, control the content of rare earth in the aluminum-rare earth alloy in a wide range, and obtain aluminum-rare earth alloy with stable content of rare earth.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic preparation of aluminum-rare earth alloys, and relates to a molten salt electrolytic preparation device for aluminum-rare earth alloys and a method for continuous preparation of aluminum-rare earth alloys by molten salt electrolysis. In particular, it relates to a device and method for preparing aluminum-rare earth alloys by molten salt electrolysis with a floating irregular cathode. Background Technology

[0002] The addition of rare earth elements to aluminum can significantly improve the properties of aluminum alloys, making aluminum-rare earth alloys widely used. Currently, aluminum-rare earth alloys can be prepared using methods such as doping, thermal reduction, and molten salt electrolysis. Among these, molten salt electrolysis is highly efficient and easily automated, and has attracted considerable attention in recent years. Molten salt electrolysis mainly includes: aluminum-rare earth co-deposition method and method of preparing aluminum-rare earth alloys by electrolyzing rare earth oxides with liquid aluminum cathode. Some corresponding research schemes have also been disclosed in the industry. Among them, aluminum-rare earth co-deposition method, such as CN02153736.4, CN03153785.5, CN03146327.4, CN200410002122.0, CN200810223984.4, CN201510458938.2, CN201710773524.8, CN202111321800.X, CN201710773531.8 and CN01138655.X, etc., to prepare aluminum-rare earth alloys. Methods for preparing aluminum-rare earth alloys by electrolysis of liquid aluminum cathodes, such as CN200620149620.2, CN201210236998.6 and CN201521067036.8, etc.

[0003] However, both methods use either liquid aluminum-rare earth alloy or liquid metallic aluminum as the cathode, with the cathode located at the bottom of the electrolytic cell. In this bottom-cathode electrolysis method, the dissolution rate of the oxide raw materials during feeding is limited, causing some oxides to sink directly to the bottom and not contact the electrolyte, thus hindering dissolution and impacting the electrolysis process. Generally, stirring is needed to accelerate the dissolution of the sediment at the bottom, but this also accelerates secondary metal loss and reduces current efficiency. Furthermore, aluminum-rare earth alloys prepared by the bottom-cathode electrolysis method are difficult to produce with stable rare earth content, requiring subsequent blending. Moreover, for the liquid aluminum cathode method, continuous addition of liquid metallic aluminum will dilute the already formed aluminum-rare earth alloy, further increasing the difficulty of obtaining aluminum-rare earth alloys with stable rare earth content.

[0004] Therefore, finding a more suitable way to solve the above-mentioned problems of the current molten salt electrolysis method, and also to achieve the continuous preparation of aluminum-rare earth alloys, has become one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide an apparatus for the molten salt electrolysis preparation of aluminum-rare earth alloys and a method for the continuous preparation of aluminum-rare earth alloys using molten salt electrolysis, particularly an apparatus for the molten salt electrolysis preparation of aluminum-rare earth alloys using a floating irregular cathode. The apparatus and method for the molten salt electrolysis preparation of aluminum-rare earth alloys provided by the present invention can avoid oxide precipitation, achieve continuous addition of aluminum liquid, and allow the rare earth content in the aluminum-rare earth alloy to be controlled within a wide range, while simultaneously obtaining aluminum-rare earth alloys with stable rare earth content.

[0006] This invention provides an apparatus for the molten salt electrolytic preparation of aluminum-rare earth alloys, including an electrolytic cell body;

[0007] The inner wall of the insulating material installed on the inner wall of the electrolytic cell;

[0008] The inner wall of the lower part of the electrolytic cell body is not provided with an insulating material inner wall.

[0009] The cathode and anode are installed inside the electrolytic cell;

[0010] The bottom of the cathode is provided with a groove.

[0011] Preferably, the electrolytic cell contains a molten electrolyte;

[0012] The cathode in the electrolytic cell may be a single cathode or multiple cathodes;

[0013] Liquid aluminum is disposed inside the electrolytic cell.

[0014] The molten electrolyte is a molten electrolyte with a density greater than that of liquid aluminum.

[0015] The electrolytic cell is equipped with an insulating material barrier plate.

[0016] Preferably, when the cathode in the electrolytic cell is a single cathode, the single cathode is immersed in liquid aluminum.

[0017] An insulating material barrier plate is provided between the cathode and the anode;

[0018] The two transverse ends of the insulating material barrier plate are fixed to the inner wall of the insulating material, and there is a gap between the bottom surface of the insulating material barrier plate and the bottom of the electrolytic cell.

[0019] The single cathode, the inner wall of the insulating material, the insulating material barrier plate, and the liquid aluminum metal form the cathode region;

[0020] Inside the electrolytic cell, the cathode region is below the molten electrolyte.

[0021] The bottom of the insulating material barrier plate is lower than the liquid level of the molten electrolyte.

[0022] Preferably, when there are multiple cathodes in the electrolytic cell, the multiple cathodes are immersed in liquid aluminum.

[0023] In the plurality of cathodes, each cathode is surrounded by an insulating material barrier plate;

[0024] In the plurality of cathodes, each cathode, an insulating material barrier plate, and liquid aluminum form a plurality of cathode regions;

[0025] There is a gap between the bottom surface of the insulating material barrier plate and the bottom of the electrolytic cell body;

[0026] Inside the electrolytic cell, the cathode region is below the molten electrolyte.

[0027] The bottom of the insulating material barrier plate is below the liquid surface of the molten electrolyte and is located in the molten electrolyte.

[0028] Preferably, the anode, molten electrolyte, insulating material barrier plate, and molten electrolyte form the anode region;

[0029] The molten electrolyte includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides;

[0030] The molten electrolyte contains barium fluoride;

[0031] The mass content of barium fluoride is greater than 15% of the total mass of the molten electrolyte;

[0032] The bottom of the inner wall of the insulating material is below the liquid surface of the molten electrolyte and is located in the molten electrolyte;

[0033] The insulating material includes an insulating composite material in which the outer layer is graphite and the inner layer is one or more of aluminum oxide, boron nitride, silicon carbide, silicon nitride, and silicon carbide / silicon nitride.

[0034] Preferably, the groove is a non-through groove;

[0035] The depth of the groove at the bottom of the cathode is not higher than the surface of the liquid aluminum metal;

[0036] The molten electrolyte is a liquid aluminum-rare earth alloy.

[0037] The preparation apparatus also includes a liquid aluminum-rare earth alloy outlet;

[0038] The liquid aluminum-rare earth alloy outlet is located at the bottom of the electrolytic cell.

[0039] This invention also provides a method for continuously preparing aluminum-rare earth alloys using molten salt electrolysis, comprising the following steps:

[0040] 1) First, molten electrolyte is placed in the bottom layer of the electrolytic cell of the molten salt electrolysis preparation device. Then, based on the molten electrolyte in the bottom layer, liquid aluminum is placed in the cathode area of ​​the electrolytic cell, and molten electrolyte is added to the anode area.

[0041] The density of the molten electrolyte is greater than that of liquid aluminum.

[0042] 2) Turn on the molten salt electrolysis preparation device, add liquid aluminum metal to the cathode area of ​​the electrolytic cell, and put rare earth oxides into the anode area of ​​the electrolytic cell for electrolysis to continuously prepare aluminum-rare earth alloys.

[0043] Preferably, the molten electrolyte comprises alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides;

[0044] The molten electrolyte contains barium fluoride;

[0045] The mass content of barium fluoride is greater than 15% of the total mass of the molten electrolyte;

[0046] The liquid aluminum is added to the electrolytic cell by slowly adding it along the cell wall.

[0047] Preferably, the method for continuous preparation of aluminum-rare earth alloys is a method for continuous preparation of aluminum-rare earth alloys with controllable composition.

[0048] The content of rare earth elements in the aluminum-rare earth alloy is controlled by adjusting the density of the molten electrolyte.

[0049] The change in the density of the molten electrolyte is achieved by adjusting the content of barium fluoride in the molten electrolyte;

[0050] The content of rare earth elements in the aluminum-rare earth alloy can be adjusted between 1% and 50%.

[0051] Preferably, the electrolysis temperature is 900~1100℃;

[0052] The rare earth elements include one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium;

[0053] During the electrolysis process, an aluminum-rare earth alloy layer is formed at the bottom of the electrolytic cell. Then, raw materials are continuously added and aluminum-rare earth alloy is continuously released to achieve continuous preparation.

[0054] The molten salt electrolysis preparation device is a floating irregular cathode molten salt electrolysis preparation device.

[0055] This invention provides an apparatus for the molten salt electrolysis preparation of aluminum-rare earth alloys, comprising an electrolytic cell body; an inner wall of insulating material disposed on the inner wall of the electrolytic cell body; an inner wall without insulating material disposed on the lower part of the inner wall of the electrolytic cell body; a cathode and an anode disposed within the electrolytic cell; and a groove provided at the bottom of the cathode. Compared with the prior art, the molten salt electrolysis preparation apparatus for aluminum-rare earth alloys provided by this invention is an apparatus for the molten salt electrolysis preparation of aluminum-rare earth alloys using a floating irregular cathode. Due to the use of a floating cathode, the added oxide raw materials can be in full and prolonged contact with the electrolyte, effectively avoiding the phenomenon in existing methods where oxides sink to the cathode and require stirring to dissolve. It can achieve continuous addition of liquid aluminum and continuous release of liquid aluminum-rare earth alloy products, resulting in a more balanced heat during the electrolysis process, stable cell temperature, and smooth operation of the electrolytic cell. It can also control the rare earth content in the alloy. By controlling the density of the molten electrolyte, the rare earth content in the aluminum-rare earth alloy can be easily controlled to meet the production requirements of aluminum-rare earth alloys for different applications. By increasing or decreasing the density of the molten salt, the rare earth content in the aluminum-rare earth alloy can be controlled within a wide range. Moreover, the use of a multi-electrode system helps to scale up the equipment while sharing the current density of the electrodes, and also helps to reduce the production cost of the inner wall of the insulating material.

[0056] The apparatus and method for preparing aluminum-rare earth alloys by molten salt electrolysis of floating irregular cathodes provided by the present invention can avoid the precipitation of oxides, realize the continuous addition of aluminum liquid, and control the rare earth content in the aluminum-rare earth alloy within a wide range, while obtaining aluminum-rare earth alloys with stable rare earth content. Attached Figure Description

[0057] Figure 1 The floating irregular cathode molten salt electrolytic cell apparatus for preparing aluminum-rare earth alloys provided in Examples 1-4 of this invention;

[0058] Figure 2 This is the floating irregular cathode molten salt electrolytic cell device for preparing aluminum-rare earth alloys provided in Embodiment 5 of the present invention. Detailed Implementation

[0059] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention and not for limiting the claims of the present invention.

[0060] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0061] The purity of all raw materials used in this invention is not particularly limited. However, it is preferable to use materials of analytical grade or those of aluminum-rare earth alloy produced by molten salt electrolysis, which have conventional purity levels.

[0062] All raw materials of this invention are conventional in the field, and each brand name and abbreviation is clear and distinct in its relevant application. Those skilled in the art can purchase them from the market or prepare them by conventional methods based on the brand name, abbreviation and corresponding application.

[0063] All processes and equipment in this invention are abbreviated as conventional abbreviations in the field. Each abbreviation is clear and unambiguous within its relevant application area, and those skilled in the art can understand its conventional process steps and equipment structure based on the abbreviation.

[0064] This invention provides an apparatus for the molten salt electrolytic preparation of aluminum-rare earth alloys, including an electrolytic cell body;

[0065] The inner wall of the insulating material installed on the inner wall of the electrolytic cell;

[0066] The inner wall of the lower part of the electrolytic cell body is not provided with an insulating material inner wall.

[0067] The cathode and anode are installed inside the electrolytic cell;

[0068] The bottom of the cathode is provided with a groove.

[0069] In this invention, the electrolytic cell preferably contains a molten electrolyte.

[0070] In this invention, the cathode in the electrolytic cell preferably includes a single cathode or multiple cathodes.

[0071] In this invention, liquid aluminum is preferably disposed in the electrolytic cell.

[0072] In this invention, the molten electrolyte is preferably a molten electrolyte with a density greater than that of liquid aluminum.

[0073] In this invention, the electrolytic cell is preferably provided with an insulating material barrier plate.

[0074] In this invention, when the cathode in the electrolytic cell is preferably a single cathode, the single cathode is immersed in liquid aluminum.

[0075] In this invention, an insulating material barrier plate is preferably provided between the cathode and the anode.

[0076] In this invention, the two transverse ends of the insulating material barrier plate are fixed to the inner wall of the insulating material. Preferably, there is a gap between the bottom surface (longitudinal bottom surface) of the insulating material barrier plate and the bottom of the electrolytic cell, that is, the two do not contact each other and are set at a certain distance. Specifically, the bottom surface refers to the longitudinal bottom surface, preferably the longitudinal bottom surface corresponding to the longitudinal plane of the barrier plate.

[0077] In this invention, the single cathode, the inner wall of the insulating material, the insulating material barrier plate, and the liquid aluminum metal preferably form the cathode region.

[0078] In this invention, the electrolyte is preferably molten electrolyte below the cathode region within the electrolytic cell.

[0079] In this invention, the liquid surface preferably refers to the upper liquid surface of the material layer (molten electrolyte, liquid aluminum, aluminum-rare earth alloy) formed in the vertical direction.

[0080] In this invention, the bottom end (longitudinal bottom end) of the insulating material barrier plate is preferably lower than the liquid surface of the molten electrolyte.

[0081] In this invention, when there are multiple cathodes in the electrolytic cell, it is preferable that the multiple cathodes are immersed in liquid aluminum.

[0082] In this invention, each of the plurality of cathodes is preferably surrounded by an insulating material barrier plate.

[0083] In this invention, each of the plurality of cathodes, the insulating material barrier plate, and the liquid aluminum preferably form a plurality of cathode regions.

[0084] In this invention, the bottom surface (longitudinal bottom surface) of the insulating material barrier plate is preferably spaced apart from the bottom of the electrolytic cell. That is, the two do not contact each other and are kept at a certain distance.

[0085] In this invention, the electrolyte is preferably molten electrolyte below the cathode region within the electrolytic cell.

[0086] In this invention, the insulating material comprises an outer layer preferably graphite, and an inner layer that is an insulating composite material of one or more of alumina, boron nitride, silicon carbide, silicon nitride, and silicon carbide / silicon nitride, more preferably graphite, with the inner layer being alumina, boron nitride, silicon carbide, silicon nitride, or silicon carbide / silicon nitride.

[0087] In this invention, the material of the insulating material barrier plate can be the same as or different from the material of the inner wall of the insulating material. The material of the insulating material barrier plate should be an insulating material.

[0088] In this invention, the bottom end of the insulating material barrier plate is preferably below the liquid surface of the molten electrolyte layer and located within the molten electrolyte layer.

[0089] In this invention, the anode, molten electrolyte, insulating material barrier plate, and molten electrolyte preferably form the anode region.

[0090] In this invention, the molten electrolyte preferably includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides.

[0091] In this invention, the molten electrolyte preferably contains barium fluoride.

[0092] In this invention, the mass content of barium fluoride is preferably greater than 15% of the total mass of the molten electrolyte, more preferably greater than 16%, and even more preferably greater than 17%.

[0093] In this invention, the bottom end (longitudinal bottom end) of the inner wall of the insulating material is preferably lower than the liquid surface of the molten electrolyte and located in the molten electrolyte.

[0094] In this invention, the groove is preferably a non-through groove. Specifically, the groove is a non-through groove, with neither end being through.

[0095] In this invention, the depth of the groove at the bottom of the cathode is preferably not higher than the surface of the liquid aluminum.

[0096] In this invention, the molten electrolyte is preferably a liquid aluminum-rare earth alloy.

[0097] In this invention, when the preparation device continuously prepares liquid aluminum-rare earth alloy, the bottom layer of the preparation device is liquid aluminum-rare earth alloy, that is, a liquid aluminum-rare earth alloy layer is formed.

[0098] In this invention, the preparation apparatus preferably includes a liquid aluminum-rare earth alloy outlet.

[0099] In this invention, the liquid aluminum-rare earth alloy outlet is preferably located at the bottom of the electrolytic cell.

[0100] This invention provides a method for the continuous preparation of aluminum-rare earth alloys using molten salt electrolysis, comprising the following steps:

[0101] 1) First, molten electrolyte is placed in the bottom layer of the electrolytic cell of the molten salt electrolysis preparation device. Then, based on the molten electrolyte in the bottom layer, liquid aluminum is placed in the cathode area of ​​the electrolytic cell, and molten electrolyte is added to the anode area.

[0102] The density of the molten electrolyte is greater than that of liquid aluminum.

[0103] 2) Turn on the molten salt electrolysis preparation device, add liquid aluminum metal to the cathode area of ​​the electrolytic cell, and put rare earth oxides into the anode area of ​​the electrolytic cell for electrolysis to continuously prepare aluminum-rare earth alloys.

[0104] In this invention, molten electrolyte is first placed in the bottom layer of the electrolytic cell of the molten salt electrolysis preparation device. Then, based on the molten electrolyte in the bottom layer, liquid aluminum is placed in the cathode area of ​​the electrolytic cell, and molten electrolyte is added to the anode area.

[0105] The density of the molten electrolyte is greater than that of liquid aluminum.

[0106] In this invention, the molten electrolyte preferably includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides.

[0107] In this invention, the molten electrolyte preferably contains barium fluoride.

[0108] In this invention, the mass content of barium fluoride is preferably greater than 15% of the total mass of the molten electrolyte, more preferably greater than 14% of the total mass of the molten electrolyte, and even more preferably greater than 13% of the total mass of the molten electrolyte.

[0109] In this invention, the preferred method for adding the liquid aluminum metal to the electrolytic cell is to add it slowly along the cell wall.

[0110] In this invention, the method for continuous preparation of aluminum-rare earth alloys is preferably a method for continuous preparation of aluminum-rare earth alloys with controllable composition.

[0111] In this invention, the content of rare earth elements in the aluminum-rare earth alloy is preferably controlled by adjusting the density of the molten electrolyte.

[0112] In this invention, the change in the density of the molten electrolyte is preferably achieved by adjusting the content of barium fluoride in the molten electrolyte.

[0113] In this invention, the content of rare earth elements in the aluminum-rare earth alloy is preferably controlled between 1% and 50%, more preferably between 5% and 40%, and even more preferably between 15% and 30%.

[0114] Finally, the molten salt electrolysis preparation device is turned on, liquid aluminum is added to the cathode area of ​​the electrolytic cell, and rare earth oxides are placed in the anode area of ​​the electrolytic cell for electrolysis to continuously prepare aluminum-rare earth alloys.

[0115] In this invention, the electrolysis temperature is preferably 900~1100℃, more preferably 940~1060℃, and even more preferably 980~1020℃.

[0116] In this invention, the rare earth elements preferably include one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium, and more preferably lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, or yttrium.

[0117] In this invention, during the electrolysis process, preferably an aluminum-rare earth alloy layer is formed at the bottom of the electrolytic cell, and then raw materials are continuously added and aluminum-rare earth alloy is continuously released to achieve continuous preparation.

[0118] In this invention, the molten salt electrolysis preparation device is specifically a floating irregular cathode molten salt electrolysis preparation device.

[0119] This invention aims to complete and refine the overall technical solution, better ensure the continuous preparation of aluminum-rare earth alloys via molten electrolysis, further improve the preparation stability and compositional stability of aluminum-rare earth alloys, and enhance the controllable range of rare earth content in aluminum-rare earth alloys. The preferred continuous preparation apparatus and method for aluminum-rare earth alloys with controllable composition include the following:

[0120] See Figure 1 , Figure 1 This refers to the floating irregular cathode molten salt electrolytic cell apparatus for preparing aluminum-rare earth alloys provided in Examples 1-4 of this invention. Wherein: the left figure is the main view, and the right figure is the top view; 1-insulating composite tube, 2-electrolytic cell body, 3-molten electrolyte, 4-valve, 5-liquid alloy outlet, 6-liquid aluminum metal, 7-irregular cathode, 8-graphite anode, 9-aluminum-rare earth alloy.

[0121] See Figure 2 , Figure 2 This is the floating irregularly shaped cathode molten salt electrolytic cell apparatus for preparing aluminum-rare earth alloys provided in Embodiment 5 of the present invention. Wherein: 1-insulating composite tube, 2-electrolytic cell body, 7-irregularly shaped cathode, 8-graphite anode.

[0122] The technical solution of this invention is implemented according to the following steps:

[0123] Electrolysis apparatus: mainly includes electrolytic cell body[2], insulating composite tube[1], graphite anode[8], cathode[7], liquid alloy outlet[5], and valve[4].

[0124] The method is as follows: the content of barium fluoride in the molten electrolyte is greater than 15% of the total weight of the molten salt, the density of the molten electrolyte is greater than the density of the liquid aluminum, the liquid aluminum [6] floats above the molten electrolyte, and the liquid aluminum [6] is surrounded by an insulating composite tube [1]. The cathode [7] is inserted into the liquid aluminum [6] as a cathode current collector. The cathode [7], the liquid aluminum [6], and the insulating composite tube [1] together form the cathode region. The bottom of the cathode [7] has a groove to prevent the liquid aluminum-rare earth alloy from mixing with the newly added aluminum liquid. Below the liquid aluminum [6] is a molten electrolyte [3] composed of alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides, in which the content of barium fluoride is greater than 15% of the total weight of the molten salt. During the electrolysis process, the anode [8] is connected to the positive terminal of the DC power supply, and the cathode [7] is connected to the negative terminal of the power supply. Rare earth oxides (which must be added in the anode region) are used as raw materials, and the electrolysis temperature is 900-1100℃. Liquid aluminum is slowly added to the cathode region. As the electrolysis proceeds, rare earth metals are deposited at the interface between the liquid aluminum [6] and the molten electrolyte [3] and form an alloy with the aluminum. When the density of the alloy is greater than the density of the molten electrolyte [3], the formed aluminum-rare earth alloy [9] drips to the bottom of the electrolytic cell and is continuously discharged through the liquid alloy outlet [5]. The rare earth content in the aluminum-rare earth alloy is controlled by adjusting the amount of barium fluoride in the electrolyte to change the density of the molten electrolyte.

[0125] Specifically, the bottom surface of the liquid aluminum metal [6] is not lower than the bottom surface of the insulating composite tube [1] surrounding the liquid aluminum metal [6].

[0126] Specifically, the density of the molten electrolyte is changed by adjusting the amount of barium fluoride in the electrolyte, thereby adjusting the rare earth content in the aluminum-rare earth alloy.

[0127] Specifically, the electrolyte densities are 2.3-2.6 g / cm³. 3 2.6-3.0 g / cm³ 3 3.0-3.3 g / cm³ 3 At that time, the mass content of rare earth in aluminum-rare earth alloys was 1%-10%, 10%-30%, and 30%-50%, respectively.

[0128] Specifically, the depth of the groove at the bottom of the cathode [7] is not higher than the upper surface of the liquid aluminum [6].

[0129] Specifically, the outer layer of the insulating composite tube [1] is graphite, and the inner layer is one of aluminum oxide, boron nitride, silicon carbide, silicon nitride, or silicon carbide combined with silicon nitride.

[0130] Specifically, the liquid alloy can be continuously discharged through a liquid alloy outlet [5], continuously extracted by vacuum siphon, or intermittently poured out after being collected in a container.

[0131] Specifically, in an electrolytic cell, the melt in the electrolytic cell is divided into one or more regions by one or more insulating composite tubes [1] to form one or more cathodes and / or one or more anodes for simultaneous electrolysis.

[0132] Specifically, the rare earth elements in the prepared alloy are one or more of the following: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

[0133] Specifically, the rare earth element content in the prepared aluminum-rare earth alloy can be controlled between 1% and 50%.

[0134] The present invention provides an apparatus and method for preparing aluminum-rare earth alloys by molten salt electrolysis with a floating, irregularly shaped cathode. The present invention employs a floating cathode, allowing the added oxide raw materials to maintain sufficient and prolonged contact with the electrolyte, effectively avoiding the phenomenon in existing methods where oxides sink to the cathode and require stirring to dissolve. It enables continuous addition of liquid aluminum and continuous release of liquid aluminum-rare earth alloy products, resulting in a more balanced heat distribution during electrolysis, stable cell temperature, and smooth operation of the electrolytic cell. Furthermore, it allows for the control of the rare earth content in the alloy. By controlling the density of the molten electrolyte, the rare earth content in the aluminum-rare earth alloy can be easily controlled, meeting the production requirements of aluminum-rare earth alloys for different applications. By increasing or decreasing the density of the molten salt, the rare earth content in the aluminum-rare earth alloy can be controlled within a wide range. Moreover, the use of a multi-electrode system facilitates equipment scaling while distributing the current density of the electrodes, and helps reduce the cost of forming the inner wall of the insulating material.

[0135] The apparatus and method for preparing aluminum-rare earth alloys by molten salt electrolysis of floating irregular cathodes provided by the present invention can avoid the precipitation of oxides, realize the continuous addition of aluminum liquid, and control the rare earth content in the aluminum-rare earth alloy within a wide range, while obtaining aluminum-rare earth alloys with stable rare earth content.

[0136] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a molten salt electrolysis preparation apparatus for aluminum-rare earth alloys and a method for continuously preparing aluminum-rare earth alloys using molten salt electrolysis. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. They are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0137] Example 1

[0138] (1) Adopt Figure 1 The device in the middle.

[0139] (2) The density of the molten electrolyte is greater than that of the liquid aluminum. The liquid aluminum [6] floats above the molten electrolyte and is surrounded by the insulating composite tube [1]. The cathode [7] is inserted into the liquid aluminum [6] as the cathode current collector. The cathode [7], the liquid aluminum [6], and the insulating composite tube [1] together form the cathode area. The bottom of the cathode [7] has a groove to prevent the liquid aluminum-rare earth alloy from mixing with the newly added aluminum liquid. The depth of the groove is the same as the upper surface of the aluminum liquid. Below the liquid aluminum [6] is the molten electrolyte [3] composed of 5%LiF-30%NaF-45%AlF3-20%BaF2. During the electrolysis process, the anode [8] is connected to the positive terminal of the DC power supply, and the cathode [7] is connected to the negative terminal of the power supply. Rare earth oxides are used as raw materials, and the electrolysis temperature is 900℃. Liquid aluminum is slowly added to the cathode area. As the electrolysis proceeds, rare earth metals are deposited at the interface between the liquid aluminum [6] and the molten electrolyte [3], and form an alloy with the aluminum. When the rare earth content in the alloy reaches 6%, the density of the alloy is 2.40-2.45 g / cm³. 3 =Equal to the density of the molten electrolyte [3] (2.4 g / cm³) 3 When the aluminum-rare earth alloy containing 6% rare earth[9] is formed, it drips to the bottom of the electrolytic cell and is continuously discharged through the liquid alloy outlet[5].

[0140] Example 2

[0141] The process is essentially the same as in Example 1, except that the molten salt system is 20% LiF-60% REF3-20% BaF2, the electrolysis temperature is 950℃, and the alloy density is 2.70-2.9 g / cm³ when the rare earth content reaches 20%. 3 =Equal to the density of the molten electrolyte [3] (2.7 g / cm³) 3 When the aluminum-rare earth alloy containing 20% ​​rare earth[9] is formed, it drips to the bottom of the electrolytic cell and is extracted by vacuum siphon.

[0142] Example 3

[0143] The process is essentially the same as in Example 1, except that the molten salt system is 10%LiF-75%REF3-15%BaF2, the electrolysis temperature is 1050℃, and the alloy density is 2.60-2.85 g / cm³ when the rare earth content in the alloy reaches 15-25%. 3 =Equal to the density of the molten electrolyte [3] (2.6 g / cm³) 3 When the aluminum-rare earth alloy containing 15-25% rare earth[9] is formed, it drips into the molybdenum crucible at the bottom of the electrolytic cell, and the molybdenum crucible ingot is taken out after a certain period of time.

[0144] Example 4

[0145] The process is essentially the same as in Example 1, except that the molten salt system is 25% LiF-25% REF3-50% BaF2, the electrolysis temperature is 1100℃, and the alloy density is 3.0-3.3 g / cm³ when the rare earth content reaches 40-50%. 3 =Equal to the density of the molten electrolyte [3] (3.0 g / cm³) 3 When the aluminum-rare earth alloy containing 40-50% rare earth[9] is formed, it drips into the tungsten crucible at the bottom of the electrolytic cell, and the molybdenum crucible ingot is taken out after a certain period of time.

[0146] Example 5

[0147] It is basically the same as Example 1, except that: it adopts Figure 2 The device in the example, i.e., the cathode current density is 1 / 2 of the cathode current density in Example 1, reduces the production cost of the insulating composite tube [1] surrounding the cathode [7] to 1 / 2, and can also obtain an aluminum-rare earth alloy containing 6% rare earth.

[0148] Comparative Example 6

[0149] Instead of continuously adding molten aluminum, the aluminum-rare earth alloy produced is extracted after electrolysis for a certain period of time and then injected back into the molten aluminum. Due to the large molten metal temperature, the furnace temperature fluctuates greatly during operation, with a maximum fluctuation of 200°C, which is extremely detrimental to the stable operation of the electrolytic cell.

[0150] Comparative Example 7

[0151] By continuously adding molten aluminum in a conventional electrolytic cell (where the liquid cathode is at the bottom), the added molten aluminum dilutes the prepared aluminum-rare earth alloy, resulting in a rare earth content in the discharged aluminum-rare earth alloy product that is lower than the target value.

[0152] Comparative Example 8

[0153] For electrolytic cells with floating cathodes, if irregularly shaped cathodes (i.e., without cathode recesses) are not used, the molten aluminum will dilute the prepared aluminum-rare earth alloy, causing the density of the liquid metal in the cathode area to always be less than the density of the molten electrolyte, and thus it cannot drip to the bottom of the electrolytic cell. This results in an increase in the amount of liquid metal in the cathode area, an excessively high liquid level, and the need to stop the continuous addition of molten aluminum.

[0154] The foregoing provides a detailed description of the apparatus and method for preparing aluminum-rare earth alloys by molten salt electrolysis of a floating irregularly shaped cathode, as provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any apparatus or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the textual description of the claims, or if they include equivalent structural elements that are not substantially different from the textual description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A molten salt electrolytic preparation apparatus for aluminum-rare earth alloys, characterized in that, Including the electrolytic cell body; The inner wall of the insulating material installed on the inner wall of the electrolytic cell; The inner wall of the lower part of the electrolytic cell body is not provided with an insulating material inner wall. The cathode and anode are installed inside the electrolytic cell; The bottom of the cathode is provided with a groove; The electrolytic cell is filled with molten electrolyte. Liquid aluminum is disposed inside the electrolytic cell. The molten electrolyte is a molten electrolyte with a density greater than that of liquid aluminum. An insulating material barrier plate is provided between the cathode and the anode; The two transverse ends of the insulating material barrier plate are fixed to the inner wall of the insulating material, and there is a gap between the bottom surface of the insulating material barrier plate and the bottom of the electrolytic cell. Inside the electrolytic cell, the cathode region is below the molten electrolyte. The bottom of the insulating material barrier plate is lower than the liquid level of the molten electrolyte; The depth of the groove at the bottom of the cathode is not higher than the surface of the liquid aluminum metal; The molten electrolyte is a liquid aluminum-rare earth alloy.

2. The molten salt electrolysis preparation apparatus according to claim 1, characterized in that, The cathode in the electrolytic cell may be a single cathode or multiple cathodes.

3. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, When the cathode in the electrolytic cell is a single cathode, the single cathode is immersed in liquid aluminum. The single cathode, the inner wall of the insulating material, the insulating material barrier plate, and the liquid aluminum metal form the cathode region.

4. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, When there are multiple cathodes in the electrolytic cell, the multiple cathodes are immersed in liquid aluminum metal; In the plurality of cathodes, each cathode is surrounded by an insulating material barrier plate; In the plurality of cathodes, each cathode, an insulating material barrier plate, and liquid aluminum form a plurality of cathode regions; There is a gap between the bottom surface of the insulating material barrier plate and the bottom of the electrolytic cell body; Inside the electrolytic cell, the cathode region is below the molten electrolyte. The bottom of the insulating material barrier plate is below the liquid surface of the molten electrolyte and is located in the molten electrolyte.

5. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, The anode, molten electrolyte, insulating material barrier plate, and molten electrolyte form the anode region; The molten electrolyte includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides; The molten electrolyte contains barium fluoride; The mass content of barium fluoride is greater than 15% of the total mass of the molten electrolyte; The bottom of the inner wall of the insulating material is below the liquid surface of the molten electrolyte and is located in the molten electrolyte; The insulating material includes an insulating composite material in which the outer layer is graphite and the inner layer is one or more of aluminum oxide, boron nitride, silicon carbide, silicon nitride, and silicon carbide / silicon nitride.

6. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, The groove is a non-through groove; The preparation apparatus also includes a liquid aluminum-rare earth alloy outlet; The liquid aluminum-rare earth alloy outlet is located at the bottom of the electrolytic cell.

7. A method for continuously preparing aluminum-rare earth alloys using the molten salt electrolysis preparation apparatus as described in any one of claims 1 to 6, characterized in that, Includes the following steps: 1) First, molten electrolyte is placed in the bottom layer of the electrolytic cell of the molten salt electrolysis preparation device. Then, based on the molten electrolyte in the bottom layer, liquid aluminum is placed in the cathode area of ​​the electrolytic cell, and molten electrolyte is added to the anode area. The density of the molten electrolyte is greater than that of liquid aluminum. 2) Turn on the molten salt electrolysis preparation device, add liquid aluminum metal to the cathode area of ​​the electrolytic cell, and put rare earth oxides into the anode area of ​​the electrolytic cell for electrolysis to continuously prepare aluminum-rare earth alloys.

8. The method according to claim 7, characterized in that, The molten electrolyte includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides; The molten electrolyte contains barium fluoride; The mass content of barium fluoride is greater than 15% of the total mass of the molten electrolyte; The liquid aluminum is added to the electrolytic cell by slowly adding it along the cell wall.

9. The method according to claim 8, characterized in that, The method for continuous preparation of aluminum-rare earth alloys is specifically a method for continuous preparation of aluminum-rare earth alloys with controllable composition. The content of rare earth elements in the aluminum-rare earth alloy is controlled by adjusting the density of the molten electrolyte. The change in the density of the molten electrolyte is achieved by adjusting the content of barium fluoride in the molten electrolyte; The content of rare earth elements in the aluminum-rare earth alloy can be adjusted between 1% and 50%.

10. The method according to claim 7, characterized in that, The electrolysis temperature is 900~1100℃; The rare earth elements include one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium; During the electrolysis process, an aluminum-rare earth alloy layer is formed at the bottom of the electrolytic cell. Then, raw materials are continuously added and aluminum-rare earth alloy is continuously released to achieve continuous preparation. The molten salt electrolysis preparation device is a floating irregular cathode molten salt electrolysis preparation device.

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