Recycling method of titanium alloy waste

Abstract

The invention belongs to the technical field of metal waste recycling, and particularly relates to a titanium alloy waste recycling method which comprises the following steps: preparing TiH2 powder into porous TiH2 particles; the titanium alloy waste is pretreated; uniformly mixing the pretreated waste material powder with the porous TiH2 particles and the TiH2 powder in an inert atmosphere to obtain a mixture; under the hydrogen atmosphere, heat treatment is conducted on the mixed material, so that TiH2 powder in the mixed powder is decomposed to generate hydrogen, under the action of the porous TiH2 particles, the generated hydrogen and a mixed powder base material are subjected to a reduction reaction, then heating continues to be conducted, heat treatment is conducted, so that the porous TiH2 particles are further decomposed, after the reaction is finished, a system is vacuumized, and an intermediate product is obtained; and the intermediate product is subjected to vacuum consumable electric arc melting, and a cast ingot is obtained. According to the method, nitrogen and oxygen elements in the titanium alloy waste can be effectively removed, and recycling of the titanium alloy waste is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycling of metal waste, and particularly relates to a method for recycling titanium alloy waste. Background Art

[0002] Titanium alloys have advantages such as light weight, high strength, good corrosion resistance, and good biocompatibility, and have broad application prospects in the fields of aviation, medical treatment, ocean, etc. However, the titanium element in titanium alloys is derived from titanium ore, and its resources are limited. During the processing of titanium alloys, the utilization rate of titanium is low, resulting in the generation of a large amount of titanium alloy waste. Given that titanium ore is a non-renewable resource, if continuously developed, there will be a risk of resource shortage. If a large amount of generated titanium alloy waste can be recycled, it will be beneficial to alleviate the problem of resource tension and can reduce the production cost of enterprises. Therefore, it is very meaningful to study the technology for recycling titanium alloy waste.

[0003] During the processing, the titanium element is extremely easy to react with oxygen and nitrogen elements to generate impurity oxides and nitrides. Therefore, removing oxygen and nitrogen elements from these titanium alloy wastes is the key. At present, the method for removing oxygen and nitrogen elements from titanium waste is to reduce them by hydrogen, reducing the oxides and nitrides in the titanium alloy to titanium and releasing oxygen and nitrogen, but the removal effect is not good yet. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a method for recycling titanium alloy waste, which can effectively remove nitrogen and oxygen elements from titanium alloy waste and realize the recycling of titanium alloy waste.

[0005] The present invention is specifically realized through the following technical solutions.

[0006] The present invention provides a method for recycling titanium alloy waste, including the following steps: Put TiH₂ powder into absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution to prepare a TiH₂ particle precursor; under an inert gas atmosphere, first perform a first heat treatment on the TiH₂ particle precursor to densify it, and then perform a second heat treatment to decompose part of the TiH₂ to generate hydrogen, obtaining porous TiH₂ particles.

[0007] Crush the titanium alloy waste under an inert atmosphere, and then wash it to obtain pretreated waste powder; under an inert atmosphere, uniformly mix the pretreated waste powder with the porous TiH₂ particles and TiH₂ powder to obtain a mixture.

[0008] Under a hydrogen atmosphere, the third heat treatment is performed on the mixture, causing the TiH₂ powder inside the mixed powder to decompose and generate hydrogen. Under the action of the porous TiH₂ particles, the generated hydrogen reacts with the substrate of the mixed powder through a reduction reaction. Subsequently, the temperature is further increased for the fourth heat treatment to cause further decomposition of the porous TiH₂ particles. After the reaction is completed, the system is evacuated to obtain an intermediate product.

[0009] The intermediate product is subjected to vacuum consumable arc melting to obtain an ingot.

[0010] Preferably, the parameters for spray drying are as follows: the inlet temperature is 200°C to 250°C, the outlet temperature is 80°C to 120°C, and the atomization pressure is 0.2 MPa to 0.5 MPa. It should be noted that the temperature during spray drying needs to be controlled and should not be too high to cause the decomposition of TiH₂.

[0011] Preferably, first, the temperature is increased at a heating rate of 3°C / min to 5°C / min to 300°C to 380°C, and held for 1 h to 2 h for the first heat treatment; then the temperature is further increased to 450°C to 500°C for the second heat treatment and held for 10 min to 20 min. The temperature of the first heat treatment is lower than the decomposition temperature of TiH₂, which densifies the TiH₂ particles while preventing the decomposition of TiH₂. The temperature of the second heat treatment is slightly higher than the decomposition temperature of TiH₂, causing partial decomposition of TiH₂ to generate hydrogen that overflows to create pores in the material. However, the degree of decomposition needs to be controlled to prevent the complete decomposition of TiH₂.

[0012] Preferably, in the mixed powder, the mass fraction of the porous TiH₂ particles is 5% to 8%, the mass fraction of the TiH₂ powder is 4% to 7%, and the balance is the pre-treated waste powder, totaling 100%.

[0013] Preferably, first, the temperature is increased at a heating rate of 3°C / min to 5°C / min to 500°C to 510°C for the third heat treatment, the hydrogen pressure is at atmospheric pressure, and the third heat treatment time is 1 h to 2 h. During the third heat treatment, the temperature is higher than the decomposition temperature of TiH₂, causing the TiH₂ powder in the mixed powder to decompose and generate hydrogen. To prevent the hydrogen inside the mixed powder from overflowing, resulting in insufficient contact between the inside of the material and hydrogen and ineffective removal of impurities inside the material, the present invention adds porous TiH₂ particles to the mixed powder. On the one hand, the porous structure can adsorb hydrogen, prevent the overflow of hydrogen, and enable hydrogen to react with the inside of the matrix material. On the other hand, the porous material is dispersed in the matrix material, and the porous structure acts as a gas flow pipeline, enabling gas to flow in the porous pipeline and making hydrogen evenly dispersed in the material to ensure the full occurrence of the reaction.

[0014] Preferably, the temperature of the fourth heat treatment is 550°C to 560°C, and the heat preservation time is 0.5 h to 1 h. After the third heat treatment, the TiH2 powder is completely decomposed, and a reduction and impurity removal reaction is carried out on the material. The function of the fourth heat treatment is to further increase the temperature, so that the porous TiH2 particles are further decomposed to generate hydrogen, and the material is further purified. It is a supplement to the third heat treatment process. Since the porous TiH2 particles have been densified, the temperature is further increased to ensure that the TiH2 inside the mixed material is completely decomposed. Through the above impurity removal reaction, it can be fully ensured that the impurity elements in the material are released from the matrix. Compared with the traditional use of high-pressure hydrogen reduction, the present invention only needs to be under a hydrogen atmosphere and at normal pressure, without the need to press hydrogen into the material under high pressure, improving the safety of the reaction. And the present invention adopts a method of reacting inside the material, which can ensure full reaction inside the material, thereby improving the impurity removal effect.

[0015] Preferably, the titanium alloy waste is sponge titanium containing oxides and / or nitrides. At this time, during vacuum consumable arc melting, after evacuating, melting is carried out, the vacuum degree < 10 -2 Pa, the arcing voltage is 20 V to 23 V, the arcing current is 1 kA to 4 kA, the melting voltage is 30 V to 35 V, the melting current is 4 kA to 4.5 kA, and the cooling time is 1 h to 1.5 h.

[0016] Preferably, it further includes: before carrying out vacuum consumable arc melting, first press the intermediate product, Mo powder and Ta powder into an electrode, and then carry out vacuum consumable arc melting. The addition amount of Mo powder is 1% to 2% of the mass of the intermediate product, and the addition amount of Ta powder is 1% to 2% of the mass of the intermediate product. The synergistic effect of adding Mo and Ta can further prevent the material from being oxidized and play a protective role. Specifically, Ta can form a solid solution with titanium, reducing the solid solubility of oxygen. The addition of Mo element can destroy the TiO2 oxide film and reduce the oxygen diffusion channel. The above two elements reduce the invasion damage of oxygen to the material from two aspects. On the one hand, they form a solid solution with titanium, reducing the binding contact between titanium and impurity elements such as oxygen. On the other hand, even if a TiO2 oxide film is generated, the oxide film can be destroyed to prevent the further expansion of the oxide film.

[0017] Preferably, the parameters for vacuum consumable arc melting after adding Mo and Ta are: after evacuating, first carry out the first melting, the vacuum degree < 10 -2Pa, the arc starting voltage is 25V - 28V, the arc starting current is 1kA - 4kA, the smelting voltage is 32V - 35V, the smelting current is 5kA - 6kA, the cooling time is 1h - 1.5h, the first smelting product is prepared. Then, the first smelting product is used as the electrode for the second smelting, the smelting current is 8kA - 10kA, the cooling time is 1h - 1.5h, and an ingot is obtained. Then, heat treatment is carried out at 900°C - 1000°C for 1h - 2h, and then it is cooled. First, smelting is carried out at a lower current to ensure that all elements are fully dissolved. Then, the smelting current is increased to refine the grains and make the structure uniform. Finally, annealing treatment is carried out to make the interior of the material a single β-phase, improving the strength and oxidation resistance of the material.

[0018] Preferably, the cleaning is carried out using a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 5% - 8%, and the mass percentage of nitric acid is 15% - 20%.

[0019] Compared with the prior art, the present invention has the following beneficial effects: Through the strategy of "deep reaction + channel opening + deep removal", the present invention effectively removes nitrogen and oxygen impurity elements in the waste material. Specifically: In the present invention, TiH2 powder is first prepared into porous TiH2 particles. Then, the titanium alloy waste material is mixed with the porous TiH2 particles and TiH2 powder to prepare a mixture. The mixture is subjected to a reduction reaction in a high-temperature and hydrogen environment. This reduction reaction is carried out step by step. First, the temperature is raised to decompose the TiH2 powder in the mixture to generate hydrogen. The generated hydrogen is adsorbed by the porous structure in the porous TiH2 particles, which can prevent it from diffusing out of the material interior and not reacting with the interior of the mixture. In addition, the porous structure is dispersed in the mixture, building a uniform channel in the material, which is beneficial to the circulation of gas inside, improving the uniformity of hydrogen dispersion inside the matrix material, facilitating the full reaction of the internal material with hydrogen, and improving the impurity removal effect. After the reaction of this process ends, the temperature is further raised to further decompose the porous TiH2 particles and further carry out a reduction and impurity removal reaction on the interior of the material. Through the above process, the impurity elements in the waste material can be effectively removed. Then, the system is evacuated to separate the impurity elements from the system, realizing the deep removal of impurity elements.

[0020] In the traditional hydrogenation scheme, hydrogen needs to enter the titanium alloy waste material under pressurized conditions, and there is a problem that hydrogen is not easily diffused, affecting the degree of the reduction reaction. The hydrogenation reduction scheme in this application can ensure that the hydrogenation reduction reaction can be carried out under low-pressure conditions, improving the safety of the process implementation.

[0021] In order to further improve the oxidation resistance of the material after impurity removal, Mo and Ta are also added to the above-mentioned material in the present invention. These two elements further prevent the material from being oxidized through synergy and play a protective role. Specifically, Ta can form a solid solution with titanium, reducing the solid solubility of oxygen. The addition of Mo element can destroy the TiO2 oxide film and reduce the oxygen diffusion channel. The above two elements reduce the invasion damage of oxygen to the material from two aspects. On the one hand, they form a solid solution with titanium, reducing the binding contact between titanium and impurity elements such as oxygen. On the other hand, even if the TiO2 oxide film is generated, it can damage the oxide film and prevent the further expansion of the oxide film. And vacuum consumable arc melting is used to realize the alloying of elements, and annealing treatment further improves the strength and oxidation resistance of the material.

[0022] The present invention recycles the waste materials contaminated by oxygen and nitrogen elements during the production process of titanium alloys, removes the impurity elements in the waste materials, and the obtained materials can be used as raw materials for products such as titanium materials and titanium alloys, realizing the recycling of waste materials, helping to alleviate the problem of shortage of titanium resources, and also being beneficial to reducing the procurement cost of titanium raw materials. Brief Description of the Drawings

[0023] Figure 1 It is a physical photo of the sponge titanium waste material to be processed in Example 1.

[0024] Figure 2 It is the XRD pattern of pure sponge titanium.

[0025] Figure 3 It is the XRD pattern of the titanium ingot prepared in Example 1.

[0026] Figure 4 It is the XRD pattern of the titanium ingot prepared in Example 1 after being placed in the air.

[0027] Figure 5 It is Figures 2 to 4 The XRD comparison chart in Detailed Embodiments

[0028] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings, but the embodiments cited are not intended to limit the present invention. In the following embodiments, the experimental methods and detection methods are all conventional methods unless otherwise specified; the reagents and materials can be obtained in the market unless otherwise specified.

[0029] During the processing of titanium alloys, a large amount of waste materials will be generated, such as sponge titanium waste. Since this sponge titanium is contaminated by oxygen and nitrogen during the processing, it cannot be used continuously. In traditional methods, oxides and other impurities in the waste materials can be reduced by hydrogen. Generally, the waste materials are placed in a high-pressure environment into which hydrogen is introduced. Since hydrogen is outside the material and needs to penetrate into the material interior to ensure that the internal material impurities are reduced and removed, this method is not only unsafe in terms of the high-pressure environment but also unable to ensure the efficient removal of material impurities, especially the problem of removing internal material impurities. To solve this problem, the present invention provides a method for recycling titanium alloy waste materials. Different from the traditional method in which hydrogen penetrates from the outside of the material into the interior for impurity removal reactions, the present invention adopts the opposite strategy, generating hydrogen in situ inside the material matrix, and by arranging a porous structure inside the material to adsorb the internal hydrogen, and the porous structure also provides a channel for the flow of hydrogen inside the material, contributing to the uniformity of the hydrogen distribution inside the material, thereby ensuring sufficient contact and reaction between the internal material and hydrogen and improving the overall impurity removal effect of the material. Specifically, it includes the following steps:

[0030] Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution to prepare a TiH2 particle precursor; under an inert gas atmosphere, first perform a first heat treatment on the TiH2 particle precursor to densify it, and then perform a second heat treatment to decompose part of the TiH2 to generate hydrogen, obtaining porous TiH2 particles.

[0031] It should be noted that the parameters for spray drying are: the inlet temperature is 200°C to 250°C, the outlet temperature is 80°C to 120°C, and the atomization pressure is 0.2 MPa to 0.5 MPa. The temperature needs to be controlled during spray drying and should not be too high to cause the decomposition of TiH2. First, heat up at a heating rate of 3°C / min to 5°C / min to 300°C to 380°C, hold for 1 h to 2 h for the first heat treatment; then continue to heat up to 450°C to 500°C for the second heat treatment, and hold for 10 min to 20 min. The temperature of the first heat treatment should be lower than the decomposition temperature of TiH2 to densify the TiH2 particles while preventing the decomposition of TiH2. The temperature of the second heat treatment is slightly higher than the decomposition temperature of TiH2 to cause part of the TiH2 to decompose and generate hydrogen to overflow and form pores in the material. However, the decomposition degree needs to be controlled to prevent the complete decomposition of TiH2. The particle size of the prepared porous TiH2 particles is 80 μm to 100 μm.

[0032] Step 2: Crush the titanium alloy waste material under an inert atmosphere, and then perform cleaning to obtain a pretreated waste powder; under an inert atmosphere, uniformly mix the pretreated waste powder with the porous TiH2 particles and TiH2 powder to obtain a mixture.

[0033] It should be noted that in the mixed powder, the particle size of the pretreated waste powder is 50 μm to 100 μm, and the particle size of the TiH2 powder is 5 μm to 10 μm. The size of the TiH2 powder is smaller than that of the porous TiH2 particles and the pretreated waste powder, and the hydrogen generated by decomposition can flow in the mixture and be adsorbed by the porous structure, ensuring the full occurrence of the reaction. The sizes of the porous TiH2 particles and the pretreated waste powder are similar, which can ensure the existence of porous channels in the mixture and contribute to the flow of hydrogen. In addition, too large a particle size is not conducive to the full occurrence of the reduction reaction and easily leads to the problem of residual impurity elements. Based on the above considerations, the size control of the mixture is carried out as described above. The cleaning is carried out using a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 5% to 8% and the mass percentage of nitric acid is 15% to 20%. It is used to remove the oxide layer on the material surface. It should also be noted that the iron element and carbon element contents in the waste need to be controlled, and the specific requirements are Fe < 3 wt% and C < 0.1 wt% to avoid the formation of high-melting-point carbides and interfere with subsequent processing. In the mixed powder, the mass fraction of the porous TiH2 particles is 5% to 8%, the mass fraction of the TiH2 powder is 4% to 7%, and the balance is the pretreated waste powder, totaling 100%.

[0034] Step 3: Under a hydrogen atmosphere, the mixture is subjected to a third heat treatment to cause the TiH2 powder inside the mixed powder to decompose and generate hydrogen. Under the action of the porous TiH2 particles, the generated hydrogen reacts with the base material of the mixed powder to carry out a reduction reaction. Then, the temperature is continuously raised for a fourth heat treatment to cause the porous TiH2 particles to further decompose. After the reaction ends, the system is evacuated to obtain an intermediate product.

[0035] It should be noted that the temperature is first raised to 500°C - 510°C at a heating rate of 3°C / min - 5°C / min for the third heat treatment. The hydrogen pressure is at atmospheric pressure, and the time for the third heat treatment is 1h - 2h. During the third heat treatment, the temperature is higher than the decomposition temperature of TiH₂, causing the TiH₂ powder in the mixed powder to decompose and generate hydrogen. To prevent the hydrogen inside the mixed powder from overflowing, resulting in the inability of the material interior to come into full contact with hydrogen and the ineffective removal of impurities inside the material, the present invention adds porous TiH₂ particles to the mixed powder. On the one hand, the porous structure can adsorb hydrogen, preventing hydrogen from overflowing and enabling hydrogen to react with the interior of the matrix material. On the other hand, the porous material is dispersed in the matrix material, and the porous structure acts as a gas flow pipeline, allowing gas to flow in the porous pipeline and enabling hydrogen to be evenly dispersed in the material, ensuring the full occurrence of the reaction. Then, the temperature is continued to be raised to 550°C - 560°C for the fourth heat treatment, and the holding time is 0.5h - 1h. After the third heat treatment, the TiH₂ powder is completely decomposed, and a reduction and impurity removal reaction is carried out on the material. The role of the fourth heat treatment is to further increase the temperature, causing the porous TiH₂ particles to further decompose and generate hydrogen, and further removing impurities from the material, which is a supplement to the third heat treatment process. Through the above impurity removal reaction, it can be fully ensured that the impurity elements in the material are released from the matrix. Compared with the traditional method of using high-pressure hydrogen reduction, the present invention only requires an atmospheric pressure in a hydrogen atmosphere and does not need to press hydrogen into the material interior under high pressure, improving the safety of the reaction. Moreover, the present invention uses a method of reacting inside the material, which can ensure full reaction inside the material and thus improve the impurity removal effect. The present invention can not only ensure the full occurrence of the hydrogenation reaction of the mixture but also does not need to use excessive and high-pressure hydrogen, improving the safety of the reaction.

[0036] Step 4: Subject the intermediate product to vacuum consumable arc melting to obtain an ingot.

[0037] The titanium alloy waste is sponge titanium containing oxides and / or nitrides. At this time, during vacuum consumable arc melting, after evacuation, melting is carried out, and the vacuum degree < 10 -2 Pa, the arcing voltage is 20V - 23V, the arcing current is 1kA - 4kA, the melting voltage is 30V - 35V, the melting current is 4kA - 4.5kA, and the cooling time is 1h - 1.5h.

[0038] Alternatively, before vacuum consumable arc melting, the intermediate product is first pressed into an electrode together with Mo powder and Ta powder, and then vacuum consumable arc melting is carried out. The addition amount of Mo powder is 1% - 2% of the mass of the intermediate product, and the addition amount of Ta powder is 1% - 2% of the mass of the intermediate product. The synergistic effect of adding Mo and Ta can further prevent the material from being oxidized and play a protective role. Specifically, Ta can form a solid solution with titanium, reducing the solid solubility of oxygen. The addition of Mo element can destroy the TiO2 oxide film and reduce the oxygen diffusion channel. The above two elements reduce the oxygen intrusion damage to the material from two aspects. On the one hand, they form a solid solution with titanium, reducing the bonding contact between titanium and impurity elements such as oxygen. On the other hand, even if the TiO2 oxide film is generated, it can damage the oxide film and prevent the further expansion of the oxide film. The parameters for vacuum consumable arc melting after adding Mo and Ta are as follows: After vacuum pumping, the first melting is carried out first, the vacuum degree < 10 -2 Pa, the arcing voltage is 25V - 28V, the arcing current is 1kA - 4kA, the melting voltage is 32V - 35V, the melting current is 5kA - 6kA, the cooling time is 1h - 1.5h, and the first melting product is prepared. Then, the first melting product is used as an electrode for the second melting, the melting current is 8kA - 10kA, the cooling time is 1h - 1.5h, and an ingot is obtained. Then, heat treatment is carried out at 900°C - 1000°C for 1h - 2h, and then cooled. First, melting is carried out at a lower current to ensure the full dissolution of each element, then the melting current is increased to refine the grains and make the structure uniform. Finally, annealing treatment is carried out to make the internal structure of the material a single β phase, improving the strength and oxidation resistance of the material.

[0039] Through the above "deep reaction + channel opening + deep removal" strategy, the present invention effectively removes nitrogen and oxygen impurity elements in the waste material. The following is a specific description of the content of the present invention through the following examples and comparative examples.

[0040] Example 1 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution, with an inlet temperature of 230°C, an outlet temperature of 100°C, and an atomization pressure of 0.3MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4°C / min to 330°C, hold for 1.5h for the first heat treatment, and then continue to heat to 470°C and hold for 15min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85μm - 100μm.

[0041] Step 2: Prepare the cleaning solution, which is a mixed aqueous solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, waste powder with a particle size of 70 μm - 100 μm after pretreatment is obtained. Mix the pretreated waste powder evenly with porous TiH2 particles and TiH2 powder (5 μm - 10 μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 6%, the mass fraction of the TiH2 powder is 5%, and the mass fraction of the pretreated waste powder is 89%.

[0042] Step 3: Under a hydrogen atmosphere and at normal pressure, first heat the mixture at a heating rate of 4 °C / min to 500 °C, hold for 1.5 h for the third heat treatment, then continue to heat to 550 °C for the fourth heat treatment, with a holding time of 0.5 h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0043] Step 4: Carry out vacuum consumable arc melting on the intermediate product. During vacuum consumable arc melting, after evacuation, perform one melting. The vacuum degree is < 10 -2 Pa, the arcing voltage is 20 V, the arcing current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and the cooling time is 1 h to obtain a titanium ingot.

[0044] Comparative Example 1 A method for recycling titanium alloy waste without adding TiH2 powder, comprising the following steps: Step 1: Place the TiH2 powder in absolute ethanol and stir evenly to prepare a mixed solution; spray-dry the mixed solution with an inlet temperature of 230 °C, an outlet temperature of 100 °C, and an atomization pressure of 0.3 MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4 °C / min to 330 °C, hold for 1.5 h for the first heat treatment, then continue to heat to 470 °C, hold for 15 min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85 μm - 100 μm.

[0045] Step 2: Prepare the cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, waste powder with a particle size of 70 μm - 100 μm after pretreatment is obtained. Mix the pretreated waste powder evenly with the porous TiH2 particles to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 11%, and the mass fraction of the pretreated waste powder is 89%.

[0046] Step 3: Under a hydrogen atmosphere and at atmospheric pressure, the mixture is first heated to 500 °C at a heating rate of 4 °C / min, held for 1.5 h for the third heat treatment, then continuously heated to 550 °C for the fourth heat treatment, with a holding time of 0.5 h. After the reaction ends, the system is evacuated to obtain an intermediate product.

[0047] Step 4: The intermediate product is subjected to vacuum consumable arc melting. During vacuum consumable arc melting, after evacuation, one melting is carried out. The vacuum degree is < 10 -2 Pa, the arcing voltage is 20 V, the arcing current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and a titanium ingot is obtained after a cooling time of 1 h.

[0048] Comparative Example 2 A method for recycling titanium alloy waste without adding porous TiH2 particles, comprising the following steps: Step 1: Prepare a cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. The sponge titanium waste is crushed under an argon atmosphere and then placed in the cleaning solution for cleaning. After cleaning with deionized water, a pretreated waste powder with a particle size of 70 μm - 100 μm is obtained. The pretreated waste powder is mixed evenly with TiH2 powder (5 μm - 10 μm) to obtain a mixture. In the mixture, the mass fraction of TiH2 powder is 11%, and the mass fraction of the pretreated waste powder is 89%.

[0049] Step 2: Under a hydrogen atmosphere and at atmospheric pressure, the mixture is first heated to 500 °C at a heating rate of 4 °C / min, held for 1.5 h for the third heat treatment, then continuously heated to 550 °C for the fourth heat treatment, with a holding time of 0.5 h. After the reaction ends, the system is evacuated to obtain an intermediate product.

[0050] Step 3: The intermediate product is subjected to vacuum consumable arc melting. During vacuum consumable arc melting, after evacuation, one melting is carried out. The vacuum degree is < 10 -2 Pa, the arcing voltage is 20 V, the arcing current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and a titanium ingot is obtained after a cooling time of 1 h.

[0051] Comparative Example 3 Step 1: Prepare the cleaning solution. The cleaning solution is a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 6% and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, waste powder with a particle size of 70 μm to 100 μm after pretreatment is obtained. Mix the pretreated waste powder evenly with TiH2 powder (5 μm to 10 μm) to obtain a mixture. In the mixture, the mass fraction of TiH2 powder is 11%, and the mass fraction of the pretreated waste powder is 89%.

[0052] Step 2: Press the mixture into an electrode and conduct vacuum consumable arc melting. During vacuum consumable arc melting, after evacuating, conduct one-time melting. The vacuum degree < 10 -2 Pa, the starting arc voltage is 20 V, the starting arc current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and after a cooling time of 1 h, a titanium ingot is obtained.

[0053] Comparative Example 4 A method for recycling titanium alloy waste, directly reducing the pretreated waste powder under high pressure, including the following steps: Step 1: Prepare the cleaning solution. The cleaning solution is a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 6% and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, pretreated waste powder with a particle size of 70 μm to 100 μm is obtained.

[0054] Step 2: Under a hydrogen atmosphere and at 10 atmospheres, first heat the pretreated waste powder at a heating rate of 4 °C / min to 500 °C, hold for 2 h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0055] Step 3: Conduct vacuum consumable arc melting on the intermediate product. During vacuum consumable arc melting, after evacuating, conduct one-time melting. The vacuum degree < 10 -2 Pa, the starting arc voltage is 20 V, the starting arc current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and after a cooling time of 1 h, a titanium ingot is obtained.

[0056] Comparative Example 5 Untreated titanium sponge waste.

[0057] Use a nitrogen and oxygen content analyzer to detect the oxygen content and nitrogen content in the samples prepared in Example 1, Comparative Examples 1 to 5. The results are shown in Table 1.

[0058] Table 1 Oxygen content and nitrogen content in the samples prepared in Example 1, Comparative Examples 1 to 5 As can be seen from the data in Table 1, in the titanium sponge waste not treated by the present invention in Comparative Example 5, it contains relatively high oxygen and nitrogen elements, while in the sample after treatment in Example 1, the oxygen content and nitrogen content are significantly reduced. This shows that the method of the present invention has excellent removal effect. In Comparative Example 1, TiH2 powder is not used, and compared with Comparative Example 5, the oxygen content and nitrogen content decrease significantly, but the effect is lower than that of Example 1. This is because when only porous TiH2 particles are added without adding TiH2 powder, during the subsequent heat treatment, the hydrogen released inside the material is slower and less in content, which affects the internal reaction of the material. In Comparative Example 2, porous TiH2 particles are not added. Although hydrogen can be generated inside the material, due to the absence of porous channels and adsorption effect, the hydrogen distribution inside the material is uneven, which also affects the reaction effect. In Comparative Example 3, the mixed material is directly subjected to vacuum consumable arc melting. Since the reaction degree cannot be guaranteed, although the impurity element content can be reduced to a certain extent, the effect is poor. Comparative Example 4 is to directly heat-treat the mixed material under high pressure. Since the internal materials cannot fully react, its effect is also lower than that of Example 1.

[0059] Figure 1 It is a photo of the titanium sponge waste to be treated in Example 1, Figure 2 It is the XRD pattern of pure titanium sponge, Figure 3 It is the XRD pattern of the titanium ingot prepared in Example 1, Figure 4 It is the XRD pattern of the titanium ingot prepared in Example 1 after being placed in air, Figure 5 It is Figures 2 to 4 The XRD comparison chart. It can be seen that the ingot prepared in Example 1 is similar to pure titanium sponge, indicating that the ingot prepared in Example 1 has good quality and can be used as a raw material.

[0060] Example 2 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution, with an inlet temperature of 230 °C, an outlet temperature of 100 °C, and an atomization pressure of 0.3 MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4 °C / min to 330 °C, hold for 1.5 h for the first heat treatment, and then continue to heat to 470 °C and hold for 15 min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85 μm to 100 μm.

[0061] Step 2: Prepare the cleaning solution. The cleaning solution is a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 6% and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, waste powder with a particle size of 50 μm - 100 μm after pretreatment is obtained. Mix the pretreated waste powder evenly with porous TiH2 particles and TiH2 powder (5 μm - 10 μm) to obtain a mixture. In the mixture, the mass fraction of porous TiH2 particles is 8%, the mass fraction of TiH2 powder is 4%, and the mass fraction of the pretreated waste powder is 88%.

[0062] Step 3: Under a hydrogen atmosphere and at normal pressure, first heat the mixture at a heating rate of 4 °C / min to 500 °C, keep it warm for 1.5 h for the third heat treatment, then continue to heat it to 550 °C for the fourth heat treatment, and keep it warm for 0.5 h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0063] Step 4: Perform vacuum consumable arc melting on the intermediate product. During vacuum consumable arc melting, after evacuation, conduct one melting. The vacuum degree is < 10 -2 Pa, the starting arc voltage is 20 V, the starting arc current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and the cooling time is 1 h to obtain a titanium ingot.

[0064] Example 3 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place the TiH2 powder in absolute ethanol and stir evenly to prepare a mixed solution; spray-dry the mixed solution, with an inlet temperature of 230 °C, an outlet temperature of 100 °C, and an atomization pressure of 0.3 MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4 °C / min to 330 °C, keep it warm for 1.5 h for the first heat treatment, then continue to heat it to 470 °C, and keep it warm for 15 min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85 μm - 100 μm.

[0065] Step 2: Prepare the cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, waste powder with a particle size of 50 μm to 100 μm after pretreatment is obtained. Mix the pretreated waste powder evenly with porous TiH2 particles and TiH2 powder (5 μm to 10 μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 5%, the mass fraction of the TiH2 powder is 7%, and the mass fraction of the pretreated waste powder is 88%.

[0066] Step 3: Under a hydrogen atmosphere and at normal pressure, first heat the mixture at a heating rate of 4 °C / min to 500 °C, hold for 1.5 h for the third heat treatment, then continue to heat to 550 °C for the fourth heat treatment, and hold for 0.5 h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0067] Step 4: Carry out vacuum consumable arc melting on the intermediate product. During vacuum consumable arc melting, after evacuation, carry out one melting. The vacuum degree is <10 -2 Pa, the starting arc voltage is 20 V, the starting arc current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and the cooling time is 1 h to obtain a titanium ingot.

[0068] Example 4 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place the TiH2 powder in absolute ethanol and stir evenly to prepare a mixed solution; spray-dry the mixed solution with an inlet temperature of 250 °C, an outlet temperature of 120 °C, and an atomization pressure of 0.2 MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 5 °C / min to 300 °C, hold for 1 h for the first heat treatment, then continue to heat to 500 °C, and hold for 10 min for the second heat treatment to obtain porous TiH2 particles with a particle size of 80 μm to 100 μm.

[0069] Step 2: Prepare the cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. Crush the titanium sponge waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, waste powder with a particle size of 50 μm to 100 μm after pretreatment is obtained. Mix the pretreated waste powder evenly with porous TiH2 particles and TiH2 powder (5 μm to 10 μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 7%, the mass fraction of the TiH2 powder is 7%, and the mass fraction of the pretreated waste powder is 86%.

[0070] Step 3: Under a hydrogen atmosphere and at normal pressure, the mixture is first heated to 500 °C at a heating rate of 4 °C / min, held for 1.5 h for the third heat treatment, then continuously heated to 550 °C for the fourth heat treatment, with a holding time of 0.5 h. After the reaction ends, the system is evacuated to obtain an intermediate product.

[0071] Step 4: The intermediate product is subjected to vacuum consumable arc melting. During vacuum consumable arc melting, after evacuation, one melting is carried out. The vacuum degree is < 10 -2 Pa, the starting arc voltage is 20 V, the starting arc current is 3 kA, the melting voltage is 32 V, the melting current is 4 kA, and a titanium ingot is obtained after a cooling time of 1 h.

[0072] Example 5 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution, with an inlet temperature of 200 °C, an outlet temperature of 80 °C, and an atomization pressure of 0.2 MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, the TiH2 particle precursor is first heated to 300 °C at a heating rate of 3 °C / min, held for 2 h for the first heat treatment, then continuously heated to 450 °C, and held for 20 min for the second heat treatment to obtain porous TiH2 particles with a particle size of 90 μm - 100 μm.

[0073] Step 2: Prepare a cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 6% and the mass percentage of nitric acid is 15%. Crush the sponge titanium waste under an argon atmosphere, then place it in the cleaning solution for cleaning. After cleaning with deionized water, a pretreated waste powder with a particle size of 50 μm - 100 μm is obtained. Mix the pretreated waste powder evenly with the porous TiH2 particles and TiH2 powder (5 μm - 10 μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 5%, the mass fraction of the TiH2 powder is 4%, and the mass fraction of the pretreated waste powder is 91%.

[0074] Step 3: Under a hydrogen atmosphere and at normal pressure, the mixture is first heated to 500 °C at a heating rate of 4 °C / min, held for 1.5 h for the third heat treatment, then continuously heated to 550 °C for the fourth heat treatment, with a holding time of 0.5 h. After the reaction ends, the system is evacuated to obtain an intermediate product.

[0075] Step 4: The intermediate product is subjected to vacuum consumable arc melting. During vacuum consumable arc melting, after evacuation, one melting is carried out. The vacuum degree is < 10 -2Pa, the arc starting voltage is 20V, the arc starting current is 3kA, the melting voltage is 32V, the melting current is 4kA, and a titanium ingot is obtained after a cooling time of 1h.

[0076] Using the same method, the oxygen content and nitrogen content in the samples prepared in Examples 2 to 5 were detected, as shown in Table 2 specifically.

[0077] Table 2 Oxygen content and nitrogen content in the samples prepared in Examples 2 to 5 As can be seen from Table 2, the oxygen content and nitrogen content in the samples prepared in Examples 2 to 5 also decreased significantly. This shows that the present invention effectively removes nitrogen and oxygen impurity elements in the waste by the strategy of "deep reaction + channel opening + deep removal".

[0078] Example 6 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution, with an inlet temperature of 230°C, an outlet temperature of 100°C, and an atomization pressure of 0.3MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4°C / min to 33°C for 1.5h for the first heat treatment, and then continue to heat to 470°C and keep it for 15min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85μm - 100μm.

[0079] Step 2: Prepare a cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 6% and the mass percentage of nitric acid is 15%. Crush the sponge titanium waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, a pretreated waste powder with a particle size of 70μm - 100μm is obtained. Mix the pretreated waste powder evenly with the porous TiH2 particles and TiH2 powder (5μm - 10μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 6%, the mass fraction of the TiH2 powder is 5%, and the mass fraction of the pretreated waste powder is 89%. <00 / samples prepared in Examples 2 to 5 were detected, as shown in Table 2 specifically.

[0077] Table 2 Oxygen content and nitrogen content in the samples prepared in Examples 2 to 5 As can be seen from Table 2, the oxygen content and nitrogen content in the samples prepared in Examples 2 to 5 also decreased significantly. This shows that the present invention effectively removes nitrogen and oxygen impurity elements in the waste by the strategy of "deep reaction + channel opening + deep removal".

[0078] Example 6 A method for recycling titanium alloy waste, comprising the following steps: Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; spray-dry the mixed solution, with an inlet temperature of 230°C, an outlet temperature of 100°C, and an atomization pressure of 0.3MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4°C / min to 330°C for 1.5h for the first heat treatment, and then continue to heat to 470°C and keep it for 15min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85μm - 100μm.

[0079] Step 2: Prepare a cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid, where the mass percentage of hydrofluoric acid is 6% and the mass percentage of nitric acid is 15%. Crush the sponge titanium waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, a pretreated waste powder with a particle size of 70μm - 100μm is obtained. Mix the pretreated waste powder evenly with the porous TiH2 particles and TiH2 powder (5μm - 10μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 6%, the mass fraction of the TiH2 powder is 5%, and the mass fraction of the pretreated waste powder is 89%.

[0080] Step 3: Under a hydrogen atmosphere and at normal pressure, first heat the mixture at a heating rate of 4°C / min to 500°C, keep it for 1.5h for the third heat treatment, and then continue to heat to 550°C for the fourth heat treatment, with a holding time of 0.5h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0081] Step 4: Press the intermediate product together with Mo powder and Ta powder into an electrode. The addition amount of Mo powder is 2% of the mass of the intermediate product, and the addition amount of Ta powder is 1% of the mass of the intermediate product. Then, carry out vacuum consumable arc melting. After evacuating, carry out the first melting first. The vacuum degree < 10 -2 Pa, the arc starting voltage is 26V, the arc starting current is 3kA, the melting voltage is 32V, the melting current is 5kA, the cooling time is 1h, prepare the first melting product. Then, use the first melting product as the electrode for the second melting. The melting current is 9kA, the cooling time is 1h, obtain an ingot. Then, carry out heat treatment at 900°C, keep warm for 1h, and then cool to obtain a titanium alloy.

[0082] Comparative Example 6 A method for recycling titanium alloy waste. Compared with Example 6, Mo is not added, and it includes the following steps: Step 1: Place TiH2 powder in absolute ethanol, stir evenly to prepare a mixed solution; carry out spray drying on the mixed solution, with an inlet temperature of 230°C, an outlet temperature of 100°C, and an atomization pressure of 0.3MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4°C / min to 330°C, keep warm for 1.5h for the first heat treatment, and then continue to heat to 470°C and keep warm for 15min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85μm - 100μm.

[0083] Step 2: Prepare a cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. Crush the sponge titanium waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, obtain a pretreated waste powder with a particle size of 70μm - 100μm. Mix the pretreated waste powder evenly with the porous TiH2 particles and TiH2 powder (particle size 5μm - 10μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 6%, the mass fraction of the TiH2 powder is 5%, and the mass fraction of the pretreated waste powder is 89%.

[0084] Step 3: Under a hydrogen atmosphere and at normal pressure, first heat the mixture at a heating rate of 4°C / min to 500°C, keep warm for 1.5h for the third heat treatment, and then continue to heat to 550°C for the fourth heat treatment. The holding time is 0.5h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0085] Step 4: Press the intermediate product together with Ta powder into an electrode. The addition amount of Ta powder is 3% of the mass of the intermediate product. Then, carry out vacuum consumable arc melting. After evacuating, carry out the first melting first. The vacuum degree < 10 -2Pa, the arc starting voltage is 26 V, the arc starting current is 3 kA, the smelting voltage is 32 V, the smelting current is 5 kA, the cooling time is 1 h, the first smelting product is prepared. Then, the first smelting product is used as the electrode for the second smelting, the smelting current is 9 kA, the cooling time is 1 h, and an ingot is obtained. Then, heat treatment is carried out at 900 °C for 1 h, and after cooling, a titanium alloy is obtained.

[0086] Comparative Example 7 A method for recycling titanium alloy waste. Compared with Example 6, Ta is not added, and it includes the following steps: Step 1: Put TiH2 powder into absolute ethanol and stir evenly to prepare a mixed solution; spray-dry the mixed solution, with the inlet temperature being 230 °C, the outlet temperature being 100 °C, and the atomization pressure being 0.3 MPa to prepare a TiH2 particle precursor. Under an argon gas atmosphere, first heat the TiH2 particle precursor at a heating rate of 4 °C / min to 330 °C, hold for 1.5 h for the first heat treatment, and then continue to heat to 470 °C and hold for 15 min for the second heat treatment to obtain porous TiH2 particles with a particle size of 85 μm - 100 μm.

[0087] Step 2: Prepare a cleaning solution, which is a mixed solution of hydrofluoric acid and nitric acid. The mass percentage of hydrofluoric acid is 6%, and the mass percentage of nitric acid is 15%. Crush the sponge titanium waste under an argon atmosphere, and then place it in the cleaning solution for cleaning. After cleaning with deionized water, a pretreated waste powder with a particle size of 70 μm - 100 μm is obtained. Mix the pretreated waste powder evenly with the porous TiH2 particles and TiH2 powder (5 μm - 10 μm) to obtain a mixture. In the mixture, the mass fraction of the porous TiH2 particles is 6%, the mass fraction of the TiH2 powder is 5%, and the mass fraction of the pretreated waste powder is 89%.

[0088] Step 3: Under a hydrogen atmosphere and at normal pressure, first heat the mixture at a heating rate of 4 °C / min to 500 °C, hold for 1.5 h for the third heat treatment, and then continue to heat to 550 °C for the fourth heat treatment, with the holding time being 0.5 h. After the reaction ends, evacuate the system to obtain an intermediate product.

[0089] Step 4: Press the intermediate product and Mo powder into an electrode. The addition amount of Mo powder is 3% of the mass of the intermediate product. Then, carry out vacuum consumable arc melting. After evacuation, first carry out the first melting, and the vacuum degree < 10 -2The starting arc voltage is 26 V, the starting arc current is 3 kA, the melting voltage is 32 V, the melting current is 5 kA, the cooling time is 1 h, and the first melting product is prepared. Then, the first melting product is used as the electrode for the second melting, the melting current is 9 kA, the cooling time is 1 h, and an ingot is obtained. Then, heat treatment is carried out at 900 °C for 1 h, and then cooled to obtain a titanium alloy.

[0090] Examples 1, 6, Comparative Example 6, and Comparative Example 7 were placed in air for 7 days, and the oxygen content in each group of samples was detected again, as shown in Table 3 specifically.

[0091] Table 3 Oxygen content data of Examples 1, 6, Comparative Example 6, and Comparative Example 7 after being placed in air for 7 days As can be seen from Table 3, after the sample after impurity removal in Example 1 was placed in air, it was oxidized again. After adding Mo and Ta elements in Example 6, the antioxidant performance of the material could be effectively improved. Only one element was added in Comparative Example 6 and Comparative Example 7. Although the antioxidant performance was improved compared with Example 1, compared with Example 6, when the total content of the added elements was the same, only adding one of the elements would reduce the antioxidant performance. This shows that only when these two elements exist simultaneously can a high antioxidant effect be achieved. This is because these two elements play roles from two aspects. Ta can form a solid solution with titanium, reducing the solid solubility of oxygen. The addition of Mo element can destroy the TiO2 oxide film and reduce the oxygen diffusion channel. The above two elements reduce the oxygen intrusion damage to the material from two aspects. On the one hand, they form a solid solution with titanium, reducing the binding contact between titanium and impurity elements such as oxygen. On the other hand, even if the TiO2 oxide film is generated, it can be destroyed to prevent the further expansion of the oxide film. These two aspects work together synergistically to improve the antioxidant effect.

[0092] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, these changes and modifications are also intended to be included.

Claims

1. A method for recycling titanium alloy waste, characterized in that, It includes the following steps: Put TiH2 powder into absolute ethanol and stir evenly to prepare a mixed solution; spray-dry the mixed solution to prepare a TiH2 particle precursor; under an inert gas atmosphere, first perform a first heat treatment on the TiH2 particle precursor to densify it, and then perform a second heat treatment to decompose part of the TiH2 to generate hydrogen, obtaining porous TiH2 particles; Crush and clean the titanium alloy waste under an inert atmosphere to obtain pretreated waste powder; under an inert atmosphere, mix the pretreated waste powder with the porous TiH2 particles and TiH2 powder evenly to obtain a mixed material; Under a hydrogen atmosphere, perform a third heat treatment on the mixed material to decompose the TiH2 powder inside the mixed powder to generate hydrogen. Under the action of the porous TiH2 particles, the generated hydrogen reacts with the substrate of the mixed powder. Then continue to raise the temperature for a fourth heat treatment to further decompose the porous TiH2 particles. After the reaction is completed, evacuate the system to obtain an intermediate product; Perform vacuum consumable electrode melting on the intermediate product to obtain an ingot.

2. The recycling method of titanium alloy waste according to claim 1, characterized in that, The parameters of spray drying are: the inlet temperature is 200°C - 250°C, the outlet temperature is 80°C - 120°C, and the atomization pressure is 0.2 MPa - 0.5 MPa.

3. The recycling method of titanium alloy waste according to claim 1, characterized in that, First, raise the temperature at a heating rate of 3°C / min - 5°C / min to 300°C - 380°C, hold for 1 h - 2 h for the first heat treatment; then continue to raise the temperature to 450°C - 500°C for the second heat treatment and hold for 10 min - 20 min.

4. The recycling method of titanium alloy waste according to claim 1, characterized in that In the mixed material, the mass fraction of the porous TiH2 particles is 5% - 8%, the mass fraction of the TiH2 powder is 4% - 7%, and the balance is the pretreated waste powder, totaling 100%.

5. The recycling method of titanium alloy waste according to claim 1, characterized in that, First, raise the temperature at a heating rate of 3°C / min - 5°C / min to 500°C - 510°C for the third heat treatment, the hydrogen pressure is normal pressure, and the third heat treatment time is 1 h - 2 h.

6. The recycling method of titanium alloy waste according to claim 1, characterized in that, The temperature of the fourth heat treatment is 550°C - 560°C, and the holding time is 0.5 h - 1 h.

7. The method for recycling titanium alloy waste according to claim 1, characterized in that The titanium alloy waste is titanium sponge containing oxides and / or nitrides.

8. The recycling method of titanium alloy waste according to claim 7, characterized in that, During vacuum consumable arc melting, after evacuation, melting is carried out with a vacuum degree < 10 -2 Pa, the striking voltage is 20V - 23V, the striking current is 1kA - 4kA, the melting voltage is 30V - 35V, the melting current is 4kA - 4.5kA, and the cooling time is 1h - 1.5h.

9. The recycling method of titanium alloy waste according to claim 1, characterized in that, It also includes: Before performing vacuum consumable electrode melting, first press the intermediate product, Mo powder and Ta powder into an electrode, and then perform vacuum consumable electrode melting. The addition amount of Mo powder is 1% - 2% of the mass of the intermediate product, and the addition amount of Ta powder is 1% - 2% of the mass of the intermediate product.

10. The method for recycling titanium alloy waste according to claim 9, characterized in that, The parameters for vacuum consumable arc melting after adding Mo and Ta are as follows: After evacuating the air, the first melting is carried out first. The vacuum degree is < 10 -2 Pa, the starting arc voltage is 25V - 28V, the starting arc current is 1kA - 4kA, the melting voltage is 32V - 35V, the melting current is 5kA - 6kA, the cooling time is 1h - 1.5h, and the product of the first melting is prepared. Then, using the product of the first melting as the electrode, the second melting is carried out. The melting current is 8kA - 10kA, the cooling time is 1h - 1.5h, and an ingot is obtained. Then, heat treatment is carried out at 900°C - 1000°C, and the holding time is 1h - 2h. Then, it is cooled.

Images