Method for producing titanium alloy by liquid metal cathode molten salt electrolytic oxidation of titanium

Abstract

This invention relates to a method for preparing titanium alloys by molten salt electrolysis of titanium oxide using a liquid metal cathode, belonging to the field of molten salt electrolysis technology. The invention employs a liquid metal cathode molten salt electrolysis apparatus. The liquid cathode metal is placed in a cavity at the center of an insulating base. A mixture of TiO2 and fluorine-chloride molten salt is added to the electrolytic cell. A graphite anode is inserted at the top of the fluorine-chloride molten salt mixture in the electrolytic cell. An inert gas is introduced, and the temperature is raised to 700-850°C. The metal in the cavity at the center of the insulating base melts to form a liquid metal alloy cathode, and the fluorine-chloride molten salt melts to form a molten salt melt. The molten salt is electrolyzed at a constant voltage under an inert atmosphere. After electrolysis, the mixture is held at this temperature for 1-5 hours under an inert atmosphere, then cooled to room temperature. The molten salt and cathode are separated to obtain the titanium alloy. The liquid cathode of this invention has a depolarizing effect on TiO2 reduction, which can enhance the electrolysis and in-situ alloying of TiO2, reduce energy consumption, achieve clean production, and improve economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to a method for preparing titanium alloys by molten salt electrolysis of titanium oxide using a liquid metal cathode, belonging to the field of molten salt electrolysis technology. Background Technology

[0002] Titanium alloys possess excellent physicochemical properties, exhibiting advantages such as low density, light weight, high specific strength, good corrosion resistance, and good biocompatibility. Currently, titanium alloy manufacturing is transitioning from a "long-process, high-energy-consumption" method to a "short-process, intelligent, and high-performance" method. Technological innovations, including smelting process reform, field-assisted additive manufacturing, and near-net-shape powder forming, are continuously driving its penetration and application in various fields such as aerospace, medical, and consumer electronics. Titanium and titanium alloy production mainly consists of three parts: titanium dioxide preparation, metallic titanium production, and titanium alloy preparation. In the Kroll process, titanium concentrate with high titanium dioxide content is first selected from the ore through physical beneficiation. This concentrate is then subjected to crushing, sulfuric acid treatment, or chlorination followed by hydrolysis and calcination to obtain titanium dioxide. The concentrate is mixed with a carbonaceous reducing agent (petroleum coke), and chlorine gas is introduced at high temperature (1000°C) to produce gaseous titanium tetrachloride. High-purity liquid titanium tetrachloride is then prepared by distillation or fractionation. Subsequently, titanium tetrachloride is purified by reduction with magnesium to obtain metallic titanium. Finally, an alloy is added and melted with metallic titanium at high temperature to prepare a titanium alloy. In summary, the preparation process of titanium alloys is long, complex, and costly. Its complex and lengthy batch process, extremely high energy consumption, expensive production costs, and significant environmental challenges (especially chlorine treatment and carbon emissions) are its most prominent drawbacks. These disadvantages directly lead to the high price of titanium metal and its products, limiting their wider application.

[0003] In traditional titanium dioxide production processes, the main sources of titanium dioxide are ilmenite or rutile and titanium-containing blast furnace slag. Separating titanium dioxide using the sulfuric acid and chloride processes easily increases production costs and causes environmental pollution. Directly using molten salt electrolysis to prepare titanium alloys from titanium dioxide can significantly shorten the resource utilization and materialization process of titanium-containing slag, while saving costs and reducing environmental pollution risks. Patents 201410724949.6 and 201910335990.7 state that titanium-containing blast furnace slag is difficult to treat using traditional sulfuric acid and chloride processes to produce titanium dioxide. Therefore, a mineral phase reconstruction method is used to make the titanium in the blast furnace slag exist in the form of titanates (CaTiO3, Na2TiO3, etc.). However, titanates have extremely low solubility in chloride molten salts, making precise control of the electrolysis process difficult, hindering continuous and stable operation, and only allowing the electrolysis of metallic titanium. Meanwhile, the forming process for preparing titanium alloys using soluble titanium-containing anodes in patent CN202110645707.8 includes anode casting, SPS sintering, vacuum sintering, and doping casting of waste titanium materials. Although this improves the utilization rate of materials, it increases the length and difficulty of the process.

[0004] The current titanium alloy manufacturing process is transitioning from a "long process with high energy consumption" to a "short process, intelligent manufacturing, and high performance" approach. Therefore, developing more efficient, continuous, low-cost, and environmentally friendly new processes for titanium alloy manufacturing has always been a research hotspot and challenge. Summary of the Invention

[0005] To address the problems of long preparation processes and high energy consumption in current titanium alloy production methods, this invention provides a method for preparing titanium alloys by molten salt electrolysis of titanium dioxide using a liquid metal cathode. This method uses a low-melting-point metal or alloy as the liquid cathode and a fluorine-chlorine mixed molten salt system as the electrolytic molten salt. Titanium alloys are directly produced by molten salt electrolysis of titanium dioxide, achieving efficient dissolution and stable electrolysis of TiO2, maintaining a stable titanium ion concentration in the molten salt. This solves the problems of slow ion diffusion and low current efficiency in existing titanium electrolysis methods, significantly improving electrolysis efficiency and stability. Furthermore, the titanium reduced on the cathode integrates into the cathode alloy, and the liquid alloy interface isolates titanium from impurity gases, effectively preventing titanium oxidation and ensuring product purity. The liquid cathode also has a depolarizing effect on titanium dioxide reduction and simultaneously enhances the electrolysis of titanate (Ti-OF), achieving energy saving and high efficiency.

[0006] A method for preparing titanium alloys by molten salt electrolysis of titanium oxide using a liquid metal cathode employs a molten salt electrolysis apparatus (see...). Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base, an insulating collar, and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolysis cell. The graphite anode is inserted into the electrolysis cell. The specific steps of the method are as follows: (1) The metal of the liquid cathode is placed in the cavity in the center of the insulating base. TiO2 and fluorine-chloride mixed molten salt are added to the electrolytic cell. The graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. The specific method for removing the chemically bound water in the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 120-150℃ at a rate of 10-20℃ / min and kept for 1-3h to remove the physical water in the fluorine-chloride mixed molten salt. Then the temperature is raised to 300-350℃ at a rate of 5-10℃ / min and kept for 36-48h to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas is introduced and the temperature is raised to 700~850℃. The metal in the central cavity of the insulating base melts to form a liquid metal alloy cathode, and the fluorine-chloride mixed molten salt melts to form a molten salt melt. The molten salt is electrolyzed under constant voltage in an inert atmosphere. (3) After electrolysis, the mixture is kept at an inert atmosphere for 1 to 5 hours, cooled to room temperature, and the molten salt and cathode are separated to obtain a titanium alloy.

[0007] Preferably, the insulating base and insulating collar are made of boron nitride, aluminum oxide, magnesium oxide or silicon oxide.

[0008] Preferably, the metal of the liquid cathode is an alloy composed of one or more of copper, tin, zinc, bismuth, and lead.

[0009] Preferably, the fluorine-chloride mixed molten salt is a NaCl-KF mixed molten salt, a KCl-NaF mixed molten salt, a NaCl-K2TiF6 mixed molten salt, a KCl-K2TiF6 mixed molten salt, a NaCl-Na2TiF6 mixed molten salt, or a KCl-Na2TiF6 mixed molten salt.

[0010] Preferably, the mass ratio of TiO2 to the fluorine-chloride mixed molten salt is 4~10:100.

[0011] Preferably, the voltage of the molten salt electrolysis is 1.0~3.5V and the time is 8~12h.

[0012] The principle of this invention for preparing titanium alloys by molten salt electrolysis of titanium dioxide using a liquid metal cathode is as follows: The liquid metal cathode is placed in the hollow center of an insulating base. The base and collar, also made of insulating material, are then placed in a graphite crucible. Titanium dioxide and fluorine-chloride molten salt (mass ratio 3-10:100) are added to the graphite crucible and mixed. Under an argon atmosphere, the molten salt electrolysis furnace is heated to 300-350°C to remove moisture. The furnace is then heated to 700-850°C. Using a graphite head as the anode and the liquid metal as the cathode, electrolysis is performed at a constant voltage of 1.0V-3.5V to achieve titanium ion (Ti) synthesis. 3+ / Ti 4+ In one step, the titanium is directly reduced to metallic titanium and fused with liquid metal to form a titanium alloy. After electrolysis, in order to allow the metallic titanium to continue to precipitate and mix evenly in the liquid alloy, the temperature is maintained for 1-5 hours, cooled to room temperature, and the insulating base containing the liquid metal cathode is removed from the molten salt. The cathode product is then separated to obtain the titanium alloy.

[0013] The beneficial effects of this invention are: (1) This invention uses a low-melting-point metal or alloy as a liquid cathode to directly electrolyze titanium dioxide in molten salt to produce titanium alloys, replacing the long, complex, and costly alloy preparation process of Kroll's production of metallic titanium followed by melting and remelting. This improves production speed and economic efficiency (see...). Figure 3 ); (2) The present invention uses a fluoride-chloride mixed molten salt as the electrolytic molten salt, which takes into account the high solubility of titanium dioxide in fluoride molten salt and the conductivity in chloride molten salt, and directly avoids the separation step of metallic titanium and electrolyte impurities. (3) The titanium reduced by the present invention is incorporated into the cathode alloy. The liquid alloy interface will isolate the titanium from contact with impurity gases, effectively preventing the titanium from being oxidized and ensuring the purity of the product. (4) The liquid cathode of the present invention has a depolarizing effect on the reduction of titanium dioxide and enhances the electrolysis of titanate, thus achieving energy saving and high efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a liquid metal cathode electrolytic cell. Figure 2 This is a schematic diagram of the insulating base structure; Figure 3 This diagram compares the traditional titanium alloy process with the process of this invention. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0016] Example 1: A method for preparing titanium alloys by molten salt electrolysis of titanium oxide using a liquid metal cathode, employing a molten salt electrolysis apparatus (see...). Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (boron nitride), an insulating collar (boron nitride), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolytic cell body. The graphite anode is inserted into the electrolytic cell body. The specific steps of the method are as follows: (1) The liquid cathode metal (zinc and tin, with a zinc to tin mass ratio of 4:1) is placed in the cavity at the center of the insulating base. TiO2 (the amount of TiO2 added is 5% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (NaCl-K2TiF6 mixed molten salt) are added to the electrolytic cell. The graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. The specific method for removing the chemically bound water in the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 120°C at a rate of 10°C / min and held for 1 hour to remove the physical water in the fluorine-chloride mixed molten salt. Then the temperature is raised to 300°C at a rate of 5°C / min and held for 3 hours to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 850°C. The metal (zinc and tin) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid zinc-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 1.5V, the molten salt is electrolyzed at a constant voltage for 6 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 3 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-zinc-tin alloy with a titanium content of 2.19%).

[0017] Example 2: A method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode molten salt apparatus (see...) Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (alumina), an insulating collar (alumina), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolysis cell. The graphite anode is inserted into the electrolysis cell. The specific steps of the method are as follows: (1) The alloy metal block (copper and tin, with a copper to tin mass ratio of 4:1) serving as the liquid cathode is placed in the cavity at the center of the insulating base. TiO2 (the amount of TiO2 added is 10% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (KCl-K2TiF6 mixed molten salt) are added to the electrolytic cell. The graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. The specific method for removing the chemically bound water in the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 150°C at a rate of 15°C / min and held for 2 hours to remove the physical water in the fluorine-chloride mixed molten salt. Then the temperature is raised to 350°C at a rate of 5°C / min and held for 4 hours to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 850°C. The alloy metal (copper and tin) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid copper-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 3.5V, the molten salt is electrolyzed at a constant voltage for 8 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 4 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-copper-tin alloy with a titanium content of 4.99%).

[0018] Example 3: A method for preparing titanium alloys by molten salt electrolysis of titanium oxide using a liquid metal cathode, employing a molten salt electrolysis apparatus (see...). Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (magnesium oxide), an insulating collar (magnesium oxide), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolysis cell. The graphite anode is inserted into the electrolysis cell. The specific steps of the method are as follows: (1) The alloy metal block (copper, zinc and tin, with a mass ratio of copper, zinc and tin of 7:2:11) serving as the liquid cathode is placed in the cavity at the center of the insulating base. TiO2 (the amount of TiO2 added is 8% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (NaCl-Na2TiF6 mixed molten salt) are added to the electrolytic cell. The graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. The specific method for removing the chemically bound water in the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 120°C at a rate of 10°C / min and held for 2 hours to remove the physical water in the fluorine-chloride mixed molten salt. Then the temperature is raised to 350°C at a rate of 10°C / min and held for 4 hours to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 750°C. The alloy metal (copper, zinc and tin) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid copper-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 3.0V, the molten salt is electrolyzed at a constant voltage for 9 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 3 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-copper-zinc-tin alloy with a titanium content of 4.10%).

[0019] Example 4: A method for preparing titanium alloys by molten salt electrolysis of titanium oxide using a liquid metal cathode, employing a molten salt electrolysis apparatus (see...). Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (silicon oxide), an insulating collar (silicon oxide), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolytic cell. The graphite anode is inserted into the electrolytic cell. The specific steps of the method are as follows: (1) An alloy metal block (copper, tin and bismuth, with a molar ratio of copper, tin and bismuth of 0.5:2:1) serving as a liquid cathode is placed in the cavity at the center of an insulating base. TiO2 (the amount of TiO2 added is 4% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (KCl-Na2TiF6 mixed molten salt) are added to the electrolytic cell. A graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. A graphite open container is placed in a molten salt electrolysis furnace to remove chemically bound water from the fluorine-chloride mixed molten salt. The specific method for removing chemically bound water from the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 150°C at a rate of 20°C / min and held for 3 hours to remove physical water from the fluorine-chloride mixed molten salt; then the temperature is raised to 350°C at a rate of 10°C / min and held for 4 hours to remove chemically bound water from the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 700°C. The alloy metal (copper, tin and bismuth) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid copper-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 2.0V, the molten salt is electrolyzed at a constant voltage for 12 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 5 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-copper-tin-bismuth alloy with a titanium content of 0.39%).

[0020] Example 5: A method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode molten salt apparatus (see...) Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (silicon oxide), an insulating collar (silicon oxide), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolytic cell. The graphite anode is inserted into the electrolytic cell. The specific steps of the method are as follows: (1) The alloy metal block (tin and lead in a mass ratio of 4:1) serving as the liquid cathode is placed in the cavity at the center of the insulating base. TiO2 (the amount of TiO2 added is 5% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (NaCl-K2TiF6 mixed molten salt) are added to the electrolytic cell. The graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. The specific method for removing the chemically bound water in the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 150°C at a rate of 20°C / min and held for 3 hours to remove the physical water in the fluorine-chloride mixed molten salt. Then the temperature is raised to 350°C at a rate of 10°C / min and held for 4 hours to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 750°C. The alloy metal (copper, tin and bismuth) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid copper-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 1.5V, the molten salt is electrolyzed at a constant voltage for 8 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 5 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-tin-lead alloy with a titanium content of 1.31%).

[0021] Example 6: A method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode molten salt apparatus (see...) Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (silicon oxide), an insulating collar (silicon oxide), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolytic cell. The graphite anode is inserted into the electrolytic cell. The specific steps of the method are as follows: (1) The alloy metal block (copper, tin and lead in a mass ratio of 20:21:9) used as liquid cathode is placed in the cavity in the center of the insulating base. TiO2 (the amount of TiO2 added is 4% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (NaCl-K2TiF6 mixed molten salt) are added into the electrolytic cell. The graphite anode is inserted into the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. The specific method for removing the chemically bound water in the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 150°C at a rate of 20°C / min and held for 3 hours to remove the physical water in the fluorine-chloride mixed molten salt. Then the temperature is raised to 350°C at a rate of 10°C / min and held for 4 hours to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 850°C. The alloy metal (copper, tin and bismuth) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid copper-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 1.5V, the molten salt is electrolyzed at a constant voltage for 10 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 5 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-copper-tin-lead alloy with a titanium content of 1.52%).

[0022] Example 7: A method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode molten salt apparatus (see...) Figure 1 and 2 The liquid metal cathode molten salt electrolysis device includes a graphite open container, an insulating base (silicon oxide), an insulating collar (silicon oxide), and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove. The outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolytic cell. The graphite anode is inserted into the electrolytic cell. The specific steps of the method are as follows: (1) An alloy metal block (antimony and tin, with a molar ratio of 1:1) serving as a liquid cathode is placed in the cavity at the center of an insulating base. TiO2 (the amount of TiO2 added is 4% of the mass of the fluorine-chloride mixed molten salt) and fluorine-chloride mixed molten salt (KCl-Na2TiF6 mixed molten salt) are added to the electrolytic cell. A graphite anode is inserted into the top of the fluorine-chloride mixed molten salt in the electrolytic cell. A graphite open container is placed in a molten salt electrolysis furnace to remove chemically bound water from the fluorine-chloride mixed molten salt. The specific method for removing chemically bound water from the fluorine-chloride mixed molten salt is as follows: the temperature is raised to 150°C at a rate of 20°C / min and held for 3 hours to remove physical water from the fluorine-chloride mixed molten salt; then the temperature is raised to 350°C at a rate of 10°C / min and held for 4 hours to remove chemically bound water from the fluorine-chloride mixed molten salt. (2) Inert gas (argon) is introduced and heated to 800°C. The alloy metal (copper, tin and bismuth) in the central cavity of the insulating base melts to form a liquid metal alloy cathode (liquid copper-tin alloy). Fluorine-chloride mixed molten salt melts to form molten salt melt. Under an inert atmosphere (argon) and a voltage of 2.8V, the molten salt is electrolyzed at a constant voltage for 12 hours. (3) After electrolysis, the mixture is kept at an inert atmosphere for 5 hours, cooled to room temperature, and the electrolytic molten salt and cathode are separated to obtain a titanium alloy (a titanium-copper-tin-bismuth alloy with a titanium content of 3.85%).

[0023] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode molten salt, characterized in that, A liquid metal cathode molten salt electrolysis device is used, which includes a graphite open container, an insulating base, an insulating collar, and a graphite anode. The insulating base has a cavity in the center and an annular groove on its outer edge. The bottom of the insulating collar is engaged in the annular groove, and the outer wall of the insulating collar is attached to the inner wall of the graphite open container. The insulating collar and the insulating base form an electrolysis cell, and the graphite anode is inserted into the electrolysis cell. The specific steps of the method are as follows: (1) The metal of the liquid cathode is placed in the cavity in the center of the insulating base. TiO2 and fluorine-chloride mixed molten salt are added to the electrolytic cell. The graphite anode is inserted to the top of the fluorine-chloride mixed molten salt in the electrolytic cell. The graphite open container is placed in the molten salt electrolysis furnace to remove the chemically bound water in the fluorine-chloride mixed molten salt. (2) Inert gas is introduced and the temperature is raised to 700~850℃. The metal in the central cavity of the insulating base melts to form a liquid metal alloy cathode, and the fluorine-chloride mixed molten salt melts to form a molten salt melt. The molten salt is electrolyzed under constant voltage in an inert atmosphere. (3) After electrolysis, the mixture is kept at an inert atmosphere for 1 to 5 hours, cooled to room temperature, and the molten salt and cathode are separated to obtain a titanium alloy.

2. The method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode according to claim 1, characterized in that: The insulating base and insulating collar are made of boron nitride, aluminum oxide, magnesium oxide or silicon oxide.

3. The method for preparing titanium alloys by electrolytic oxidation of titanium with liquid metal cathode molten salt according to claim 1, characterized in that: The metal of the liquid cathode is an alloy composed of multiple or more of copper, tin, zinc, bismuth, and lead.

4. The method for preparing titanium alloys by electrolytic oxidation of titanium with molten salt using a liquid metal cathode according to claim 1, characterized in that: Fluorine-chloride mixed molten salts include NaCl-KF mixed molten salt, KCl-NaF mixed molten salt, NaCl-K2TiF6 mixed molten salt, KCl-K2TiF6 mixed molten salt, NaCl-Na2TiF6 mixed molten salt, or KCl-Na2TiF6 mixed molten salt.

5. The method for preparing titanium alloys by electrolytic oxidation of titanium with molten salt using a liquid metal cathode according to claim 1, characterized in that: The mass ratio of TiO2 to fluorine-chloride mixed molten salt is 4~10:

100.

6. The method for preparing titanium alloys by electrolytic oxidation of titanium oxide using a liquid metal cathode according to claim 1, characterized in that: The voltage for molten salt electrolysis is 1.5~3.5V.

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