Method for preparing lanthanum-samarium alloy from molten salt electrolysis lanthanum-samarium slag

Abstract

The present application belongs to the technical field of chemical substance extraction, and particularly relates to a method for preparing lanthanum-samarium alloy from molten salt electrolysis lanthanum-samarium slag, which comprises: selecting a graphite electrolytic cell, taking inert metal tungsten as a cathode, taking graphite as an anode, taking LaF3-SmF3-LiF as a molten salt electrolyte system, adding completely oxidized lanthanum-samarium slag into the electrolyte system, and co-depositing lanthanum-samarium alloy at the cathode. The method for preparing lanthanum-samarium alloy from molten salt electrolysis lanthanum-samarium slag has simple whole production process, low requirement for equipment, large lanthanum-samarium slag treatment capacity, continuous and stable production, only produces carbon dioxide, carbon monoxide and a small amount of fluorine-containing gas in the electrolysis process, has small environmental pollution, simultaneously reduces the production cost of metallic samarium, and improves the economic benefit of enterprises.

Description

Technical Field

[0001] This specification relates to the field of chemical substance extraction technology, and more particularly to a method for preparing lanthanum-samarium alloys by molten salt electrolysis of lanthanum-samarium slag. Background Technology

[0002] Samarium metal possesses excellent magnetic properties, hydrogen storage capacity, and luminescence properties, and is widely used in rare earth permanent magnet materials, hydrogen storage materials, luminescent materials, and laser materials.

[0003] The thermal reduction of samarium oxide by lanthanum is the main method for preparing metallic samarium. However, this reduction process generates a large amount of lanthanum-samarium slag, leading to its accumulation over long-term production. The fully oxidized lanthanum-samarium slag is primarily a mixture of lanthanum oxide and samarium oxide, accounting for approximately 99.88%, with alumina at approximately 0.06%, iron oxide at approximately 0.6%, and silicon oxide at approximately 0.05%.

[0004] The molten salt electrolysis method for preparing mixed rare earth metals and single rare earth metals and their alloys is a mature and reliable process with high output, continuous production capability, low impurity content, and stable quality.

[0005] Samarium is a variable-valence element. In molten salt electrolysis, metallic samarium cannot be deposited alone and needs to be combined with other metals to form samarium alloys by means of an active cathode or induced co-deposition. The literature (An Maozhong, et al. Study on electrodeposition of Sm-Co alloy [J]. Journal of Natural Science of Heilongjiang University, 2010, 27(3)) reported that Sm-Co alloy films were successfully prepared by electrodeposition in the ionic liquid 1-butyl-3-methylimidazolium fluoroborate ([BMIM]BF4) system. The alloy coating was dense, uniform, finely crystallized, and well adhered to the substrate. The literature (Li Jiaxin, et al. Electrodeposition and magnetic properties of Sm_xFe17 alloy film in urea molten salt [J]. Rare Metal Materials and Processes, 2008, 37(12)) reported that Sm_xFe17 alloy film was studied in low-temperature melt using cyclic voltammetry. 3+ The cathodic electrochemical behavior was studied, and SmFe2, SmFe3, and Sm2Fe were obtained on a Cu substrate through induced co-deposition. 17The mixed alloy phase. The literature (Chen Lang, et al. Study on the electrochemical behavior of Sm on different cathodes and the mechanism of alloy preparation in molten salt system [D]. Harbin Engineering University, 2013) reported that the electrochemical mechanism of samarium ions in LiCl-KCl molten salt system was studied, and Ni5Sm and Ni2Sm alloys were prepared in LiCl-KCl-SmCl3 (10wt.%) molten salt system on solid Ni electrode by constant potential method and constant current method, respectively. The literature (Liu Yuhui, et al. Preparation and performance study of Sm-based functional compounds by molten salt electrolysis [D]. Harbin Engineering University, 2018) reported that SmCu6, SmCu5, and SmCu alloys with dendritic crystal structures were prepared by constant potential electrolysis at -1.90V, -2.10V, and -230V on a Mo electrode in a LiCl-KCl-CuCl2 (2.0% wt.%)-SmCl3 (2.0% wt.%) molten salt system at 973K temperature. The literature (Xue Yun, et al. Direct electrochemical reduction of Sm2O3 and formation of Al-Sm alloy in LiCl-KCl-AlCl3 molten salt [J]. Journal of Inorganic Chemistry, 2013, 29(9)) reported that the electrochemical behavior of Sm2O3 in LiCl-KCl-AlCl3 molten salt system was studied. Mo was used as the cathode and Al-Sm alloy was obtained by electrolysis from LiCl-KCl-AlCl3-Sm2O3 molten salt using a constant current method.

[0006] In summary, this application proposes a method for preparing lanthanum-samarium alloys by molten salt electrolysis of lanthanum-samarium slag to solve the aforementioned problems. Summary of the Invention

[0007] The present invention aims to solve the problems mentioned in the background art. The purpose of one or more embodiments of this specification is to provide a method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag, which has small packaging size, high consistency, and can limit the field of view of chip acoustic waves.

[0008] Based on the above objectives, one or more embodiments of this specification provide a method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag, comprising: selecting a graphite electrolytic cell, using inert metal tungsten as the cathode and graphite as the anode, using LaF3-SmF3-LiF as the molten salt electrolyte system, adding fully oxidized lanthanum-samarium slag to the electrolyte system, and co-depositing lanthanum-samarium alloy at the cathode.

[0009] Preferably, the electrolysis temperature of this method is 980℃-1020℃.

[0010] Preferably, the distance between the anode and the cathode in this method is 8 cm.

[0011] Preferably, the cathode current density in this method is 6.68–7.66 A / cm². 2 .

[0012] Preferably, the anolyte current density in this method is 1.47–1.69 A / cm². 2 .

[0013] Preferably, the pressure inside the graphite electrolytic cell in this method is 8-8.6V.

[0014] Preferably, the mass percentage composition of the LaF3-SmF3-LiF molten salt electrolyte system in this method is as follows:

[0015] LaF, 332.7-35.6%;

[0016] SmF, 334.1-38.8%; and

[0017] LiF, 27.6-30.5%.

[0018] Preferably, the fully oxidized lanthanum-samarium slag in this method consists of 90%-91.4% lanthanum oxide and 7.8%-9% samarium oxide.

[0019] Preferably, the La-Sm alloy finally prepared by this method contains 92.6-94.4% lanthanum and 5.5-7.3% samarium.

[0020] Based on the above description, the present invention has the following beneficial effects:

[0021] The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag proposed in this invention has a simple overall production process, low equipment requirements, large lanthanum-samarium slag processing capacity, and can be continuously and stably produced. During the electrolysis process, only carbon dioxide, carbon monoxide and a small amount of fluorine-containing gas are generated, resulting in minimal environmental pollution.

[0022] The preparation of lanthanum-samarium alloys from lanthanum-samarium slag via molten salt electrolysis is a novel method for treating lanthanum-samarium slag, not reported in domestic or international literature or patents. Large quantities of lanthanum-samarium slag are generated after the reduction of metallic samarium. By electrolyzing this lanthanum-samarium slag using molten salt electrolysis to prepare lanthanum-samarium alloys, the resulting alloys can be reused as a reducing agent in the production of metallic samarium. This allows for the reuse of lanthanum and the recovery of samarium, fully utilizing the value of the lanthanum-samarium slag, achieving a closed-loop metallic samarium production process, solving the problem of storing and disposing of large quantities of lanthanum-samarium slag generated during metallic samarium production, reducing the production cost of metallic samarium, and improving the economic benefits for enterprises. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments.

[0024] According to an embodiment of the present invention, a method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag includes: selecting a graphite electrolytic cell, using inert metal tungsten as the cathode and graphite as the anode, using LaF3-SmF3-LiF as the molten salt electrolyte system, adding fully oxidized lanthanum-samarium slag to the electrolyte system, and co-depositing lanthanum-samarium alloy at the cathode.

[0025] As an improvement to the above scheme, the electrolysis temperature of this method is 980℃-1020℃.

[0026] As an improvement to the above scheme, the distance between the anode and the cathode in this method is 8 cm.

[0027] As an improvement to the above scheme, the cathode current density in this method is 6.68–7.66 A / cm². 2 .

[0028] As an improvement to the above scheme, the anode current density in this method is 1.47–1.69 A / cm². 2 .

[0029] As an improvement to the above scheme, the pressure inside the graphite electrolytic cell in this method is 8-8.6V.

[0030] As an improvement to the above scheme, the mass percentage composition of the LaF3-SmF3-LiF molten salt electrolyte system in this method is as follows:

[0031] LaF, 332.7-35.6%;

[0032] SmF, 334.1-38.8%; and

[0033] LiF, 27.6-30.5%.

[0034] Preferably, the fully oxidized lanthanum-samarium slag in this method consists of 90%-91.4% lanthanum oxide and 7.8%-9% samarium oxide.

[0035] As an improved version of the above scheme, the La-Sm alloy finally prepared by this method contains 92.6-94.4% lanthanum and 5.5-7.3% samarium.

[0036] Example 1

[0037] Using LaF3-SmF3-LiF as the molten salt electrolyte system, with LaF3, SmF3, and LiF mass percentages of 34%, 36.6%, and 29.4%, respectively, a measured amount of fully oxidized lanthanum-samarium slag was added to the electrolyte system. Inert tungsten was used as the cathode, graphite as the anode, and the electrolysis temperature was 990℃ with an electrode spacing of 8 cm and a cathode current density of 7.1 A / cm². 2 Anode current density 1.55 A / cm2 With a cell voltage of 8.3–8.6V, after 1.5 hours of electrolysis, a lanthanum-samarium alloy was co-deposited at the cathode, with lanthanum and samarium contents of 92.54% and 7.32%, respectively.

[0038] Example 2

[0039] Using LaF3-SmF3-LiF as the molten salt electrolyte system, with LaF3, SmF3, and LiF mass percentages of 34%, 36.6%, and 29.4%, respectively, a measured amount of fully oxidized lanthanum-samarium slag was added to the electrolyte system. Inert tungsten was used as the cathode, graphite as the anode, and the electrolysis temperature was 1010℃ with an electrode spacing of 8 cm and a cathode current density of 7.5 A / cm². 2 Anode current density 1.64 A / cm 2 With a cell voltage of 8.2–8.5V, after 1.5 hours of electrolysis, a lanthanum-samarium alloy was co-deposited at the cathode, with lanthanum and samarium contents of 93.06% and 6.7%, respectively.

[0040] Example 3

[0041] Using LaF3-SmF3-LiF as the molten salt electrolyte system, with LaF3, SmF3, and LiF mass percentages of 33.2%, 38.8%, and 28%, respectively, a quantitative amount of fully oxidized lanthanum-samarium slag was added to the electrolyte system. Inert tungsten was used as the cathode, graphite as the anode, and the electrolysis temperature was 1000℃ with an electrode spacing of 8 cm and a cathode current density of 7.1 A / cm². 2 Anode current density 1.55 A / cm 2 With a cell voltage of 8.3–8.6V, after 1.5 hours of electrolysis, a lanthanum-samarium alloy was co-deposited at the cathode, with lanthanum and samarium contents of 93.36% and 6.44%, respectively.

[0042] One or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the scope of protection of this disclosure.

Claims

1. A method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag, characterized in that, include: A graphite electrolytic cell was selected, with inert tungsten as the cathode and graphite as the anode. The LaF3-SmF3-LiF molten salt electrolyte system was used. Fully oxidized lanthanum samarium slag was added to the electrolyte system, and lanthanum samarium alloy was co-deposited at the cathode. The mass percentage composition of the LaF3-SmF3-LiF molten salt electrolyte system is as follows: LaF, 33.7-35.6%; SmF, 33.1-38.8%; and LiF, 27.6-30.5%.

2. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, The electrolysis temperature of this method is 980℃-1220℃.

3. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, In this method, the distance between the anode and the cathode is 8-20 cm.

4. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, In this method, the cathode current density ranges from 4.68 to 10.66 A / cm². 2 .

5. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, In this method, the anodic current density ranges from 0.47 to 3.69 A / cm². 2 .

6. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, In this method, the pressure inside the graphite electrolytic cell is 8-1.6V.

7. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, In this method, the fully oxidized lanthanum-samarium slag consists of 70%-95.4% lanthanum oxide and 4.8%-30% samarium oxide.

8. The method for preparing lanthanum-samarium alloy by molten salt electrolysis of lanthanum-samarium slag according to claim 1, characterized in that, The La-Sm alloys finally prepared by this method contain 72-96.4% lanthanum and 3.5-27% samarium.