Method for preparing ultralow-oxygen TC4 powder through primary reduction-electrochemical deoxidation

Abstract

The invention provides a method for preparing ultralow-oxygen TC4 powder through primary reduction-electrochemical deoxidation, and belongs to the technical field of ultralow-oxygen TC4 powder preparation. The preparation method comprises the following steps: (1) taking titanium dioxide powder, aluminum powder, vanadium pentoxide powder and magnesium powder as raw materials, and uniformly mixing according to a certain proportion to obtain mixed powder; (2) adding the mixed powder into a self-propagating reaction furnace, initiating a self-propagating reaction, and cooling the reaction material to obtain a self-propagating reaction product; (3) placing the self-propagating reaction product in a reaction kettle, leaching the intermediate product by using hydrochloric acid as a leaching solution to obtain a filtrate and a leaching product, removing the filtrate, and washing and vacuum-drying the leaching product to obtain primarily reduced TC4 powder; and (4) the TC4 powder obtained through primary reduction serves as a cathode, a graphite rod serves as an anode, electrochemical deoxidation and washing are conducted in CaCl2-based molten salt, a cathode product is obtained, and the TC4 powder with the ultralow oxygen content is obtained after vacuum drying. The method is low in raw material cost, and the oxygen content of the obtained TC4 powder is lower than 0.10 wt%.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-low oxygen TC4 powder preparation, and specifically relates to a method for preparing ultra-low oxygen TC4 powder through primary reduction-electrochemical deoxidation. Background Art

[0002] Titanium-based materials are widely used in aerospace, automotive, biomedical and marine fields due to their superior properties, such as light weight, high mechanical strength, corrosion resistance and good stability.

[0003] TC4 (Ti-6Al-4V) powder is usually made of TC4 alloy as the basic raw material and needs to be prepared through steps such as sponge titanium, aluminum and vanadium smelting and casting, plastic processing, machining, hydrogenation and dehydrogenation or gas atomization, resulting in its high price.

[0004] The patent with application number CN202310913983.7 discloses a homogeneous TC4 titanium alloy preparation device and method, which belongs to the field of titanium alloy additive manufacturing technology. The specific process is as follows: First, the delivery of three metal powders of Ti, Al and Al-50V is accurately controlled by a high-precision intelligent powder feeder to achieve the composition control of TC4 titanium alloy; then, a powder mixing device with a complex internal flow channel structure is used to stably and quickly achieve the mixing of the above three powders, providing a multi-material metal mixed powder with uniform mixing and easy-to-adjust composition for the TC4 titanium alloy additive manufacturing process; finally, an ultra-high-speed annular powder feeding nozzle structure is used as the spraying device for the above mixed powder, providing a powder flow with stable flow state and high convergence for the additive manufacturing process of TC4 titanium alloy; the method described in the present invention realizes the uniform preparation of TC4 titanium alloy and the rapid prototyping of extremely complex structures, avoiding the defects of the numerous processes of traditional complex structure TC4 titanium alloy additive manufacturing.

[0005] The patent with application number CN202310256272.7 provides a TC4 titanium alloy powder for additive manufacturing. In terms of mass percentage, the TC4 titanium alloy powder for additive manufacturing includes: Al 5.50-6.75%, V 3.5-4.5%, Fe≤0.30%, C≤0.08%, O≤0.18%, N≤0.05% and H≤0.015%. The preparation method includes: mixing spheroidized titanium dioxide, vanadium pentoxide, aluminum, slag-making agent and exothermic agent, putting them into a mold for compaction, and then vacuum roasting, cooling, induction melting and refining, and gas atomization powder making in sequence to obtain the TC4 titanium alloy powder for additive manufacturing. The present invention adopts induction melting gas atomization powder spraying technology to directly prepare TC4 titanium alloy powder. Compared with the preparation of TC4 titanium alloy powder using TC4 wire or rod as raw material, while shortening the production cycle, it also greatly reduces the production cost, which is conducive to expanding its application field.

[0006] The patent with application number CN202210473884.7 discloses a process for preparing TC4 alloy powder by calcium thermal self-propagating reaction, and the process steps are as follows: 1) Mix the dried nano titanium dioxide powder, aluminum powder, vanadium pentoxide and calcium powder in proportion to obtain a mixed material; add the mixed material to a self-propagating reactor to initiate a self-propagating reaction, and after the reaction material is cooled, obtain a reduced product TC4 alloy powder and a mixture of calcium oxide; place the reduced product TC4 alloy powder and the mixture of calcium oxide in a closed reactor, and leach the crude product with dilute hydrochloric acid as the leaching liquid, and obtain a filtrate and a leached product after filtering; wash the leached product and vacuum dry it to obtain the product TC4 alloy powder. The present invention obtains a TC4 alloy powder product with high purity, high sphericity, good fluidity, uniform particle size distribution and low oxygen content through self-propagating high temperature reaction and acid leaching reaction. Although the patent uses self-propagation to prepare TC4 powder, the oxygen content of the TC4 powder obtained by direct self-propagating reaction is higher than 0.1wt%, which cannot meet the requirements of the oxygen content of TC4 powder in the fields of aerospace and the like.

[0007] In view of the problems of high price and high oxygen content of existing TC4 powder, the present invention prepares primary reduced TC4 powder by self-propagating rapid reduction, and obtains TC4 powder with ultra-low oxygen content by electrochemical deoxidation. The process is simple and the production cost is significantly reduced. Summary of the invention

[0008] The technical task of the present invention is to provide a method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation to solve the problem of high cost in the preparation of TC4 powder in the prior art, and obtain ultra-low oxygen content titanium powder by self-propagating high temperature synthesis and electrochemical deoxidation. The method has low raw material cost, simple operation, low requirements on process conditions and equipment, and has the potential for continuous industrial production. The titanium powder prepared by the method has the advantages of high purity and low non-metallic impurity content.

[0009] A method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation comprises the following steps:

[0010] Step 1: Mix the ingredients

[0011] The titanium dioxide powder, aluminum powder, vanadium pentoxide powder and magnesium powder are dried and mixed evenly to obtain a mixed powder;

[0012] Step 2: Self-propagating preparation of primary reduced TC4 powder

[0013] After the mixed powder is pressed into a block blank, it is added into a self-propagating reaction furnace to initiate a self-propagating reaction, and after the reaction material is cooled, a self-propagating reaction product is obtained;

[0014] Step 3: Pickling primary reduction TC4 powder

[0015] The self-propagating reaction product is placed in a reaction kettle, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product to obtain a filtrate and a leaching product, the filtrate is removed, and the leaching product is washed and vacuum-dried to obtain primary reduced TC4 powder;

[0016] Step 4: Primary reduction TC4 powder electrochemical deoxidation

[0017] The primary reduced TC4 powder after pickling is placed in a cathode basket as a cathode, and a graphite rod is used as an anode for electrochemical deoxidation in a CaCl2-based molten salt;

[0018] Step 5: Washing the electrochemical deoxidation product

[0019] The cathode product in step 4 is washed and vacuum dried to obtain TC4 powder with ultra-low oxygen content.

[0020] Furthermore, in the step 1, in the mixed powder, the total amount of magnesium is calculated according to a molar ratio of magnesium to vanadium pentoxide of 2.5:1 and a molar ratio of magnesium to titanium dioxide of 1 to 1.5:1, and then added; the masses of vanadium pentoxide and titanium dioxide are added according to the contents of vanadium and titanium in the TC4 component, and the mass of aluminum is added according to an excess of 10% of the aluminum content in the TC4 component.

[0021] Furthermore, the self-propagating reaction time in step 2 is 5 to 90 seconds.

[0022] Furthermore, in the step 3, the leaching temperature is 20-60° C., the leaching time is 30-180 min, and the concentration of hydrochloric acid is 1-3 mol / L.

[0023] Furthermore, in step 3, oxygen is introduced during the leaching process to inhibit the leaching product from adsorbing hydrogen, and the oxygen flow rate is greater than 0.1 L / min.

[0024] Furthermore, in the step 4, the TC4 powder is placed in a cathode basket made of a pure titanium mesh of 100 to 200 meshes as a cathode, the electro-deoxidation process is protected by argon at a flow rate of 0.1 to 1 L / min, the applied voltage is 3.3 to 3.8 V, the reaction temperature is 850 to 1050° C., and the deoxidation time is 8 to 12 h.

[0025] Furthermore, in the step 4, the primary reduced TC4 powder is directly placed loosely in the cathode basket for electrochemical deoxidation without being pressed into blocks, and the electrolyte is CaCl2 molten salt.

[0026] Furthermore, in step 4, the oxygen content of the obtained TC4 powder with ultra-low oxygen content is less than 0.1 wt%.

[0027] Furthermore, in step 5, the cathode product is washed in the order of deionized water, hydrochloric acid, alcohol, and deionized water; the alcohol is one or more of methanol, ethanol, and propanol.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention proposes a new idea of ​​preparing ultra-low oxygen TC4 powder by synergistically combining primary reduction and electrochemical deoxidation, that is, firstly reducing the TC4 powder by a self-propagating rapid reaction, then electrochemically deoxidizing the powder, and removing oxygen from the primary reduced TC4 powder in situ by using the reducing agent produced by electrolyte electrolysis during the electro-deoxidation process, and finally purifying the deoxidation product by acid washing to obtain high-purity TC4 powder.

[0030] The present invention adopts a short-process self-propagating method to prepare primary reduced TC4 powder, and the reduction reaction can occur without the need for an additional heat source to maintain, and there is no intermediate process. The primary reduced TC4 powder is deoxidized by using a reducing agent obtained by electrolyte electrolysis, which not only further reduces the cost, but also is conducive to obtaining ultra-low oxygen content TC4 powder due to its process's elimination characteristics of deoxidation products. The method of preparing ultra-low oxygen titanium powder by coupling the self-propagating metallurgy concept and the electrochemical deoxidation technology in series is in line with the national economic development strategy of reducing raw material costs and saving energy, and its industrialization benefits and social benefits are very considerable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a process flow chart of the method for preparing TC4 powder with ultra-low oxygen content by primary reduction-electrochemical deoxidation. DETAILED DESCRIPTION

[0032] The present invention is further described in detail in conjunction with the examples. The titanium dioxide, vanadium pentoxide, aluminum powder, magnesium powder, calcium chloride and hydrochloric acid used in the following examples are all industrial grade products, wherein the magnesium powder has a particle size of ≤0.5 mm and the calcium chloride has a purity of ≥96%.

[0033] The self-propagating reaction time in the following examples is 5 to 90 seconds. The process flow chart of the method for preparing ultra-low oxygen content TC4 powder by primary reduction-electrochemical deoxidation used in the following examples is shown in Figure 1 .

[0034] Example 1

[0035] A method for preparing ultra-low oxygen content titanium powder by primary reduction-electrochemical deoxidation is carried out according to the following steps:

[0036] Step 1: Mix the ingredients

[0037] Titanium dioxide powder and vanadium pentoxide powder are placed in an oven and dried at 100° C. for 24 hours to obtain dried titanium dioxide powder and vanadium pentoxide powder; the dried titanium dioxide powder and vanadium pentoxide powder are mixed with aluminum powder and magnesium powder, wherein: the mass of vanadium pentoxide and titanium dioxide is added according to the content of vanadium and titanium in the TC4 component, the mass of magnesium powder is calculated according to the molar ratio of Mg:TiO2=1.5:1 and Mg:V2O5=2.5:1, and the mass of aluminum powder is added in an excess of 10% of the theoretical content of aluminum in the ideal product TC4 powder to obtain a mixed material;

[0038] Step 2: Self-propagating preparation of primary reduced TC4 powder

[0039] The mixed material is pressed at 10 MPa to obtain a block billet, the block billet of the mixed material is added into a self-propagating reactor, a self-propagating reaction is initiated by local ignition, and a self-propagating reaction product is obtained after the reaction material is cooled.

[0040] Step 3: Pickling primary reduction TC4 powder

[0041] The self-propagating reaction product is placed in a closed reactor, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product. The leaching temperature is 25° C., and the leaching time is 120 min. A filtrate and a leached product are obtained. The filtrate is removed, and the leached product is washed and vacuum-dried to obtain primary reduced TC4 powder with a median particle size of 18 μm. The molar concentration of hydrochloric acid is 1 mol / L, and the amount of dilute hydrochloric acid added to the self-propagating reaction product is a ratio of 10% excess hydrochloric acid required by the reaction theory, and the oxygen flow rate during the pickling process is 0.15 L / min.

[0042] Step 4: Primary reduction TC4 powder electrochemical deoxidation

[0043] The TC4 powder was loosely packed and placed in a pure titanium mesh of 100-200 mesh as the cathode, and a high-purity graphite rod was used as the anode, and electrochemical deoxidation was carried out in CaCl2 molten salt. During the electro-deoxidation reaction, the anode and cathode and the electrolyte were placed in a closed resistance furnace. The electro-deoxidation process was protected by argon at a flow rate of 0.5L / min, the applied voltage was 3.3V, the reaction temperature was 850℃, the reaction time was 5h, and after the reaction was completed, the cathode product cooled to room temperature was taken out of the resistance furnace.

[0044] Step 5: Washing the electrochemical deoxidation product

[0045] The cathode product after electrochemical deoxidation is placed in a closed reactor, and the cathode product in the above step 3 is washed in the order of deionized water, hydrochloric acid (1 mol / L), methanol-ethanol-propanol, and deionized water. After vacuum drying, high-quality TC4 powder with ultra-low oxygen content is obtained, wherein the oxygen content in the TC4 powder is less than 0.1wt%, and the median particle size is 29μm.

[0046] Example 2

[0047] A method for preparing ultra-low oxygen content titanium powder by primary reduction-electrochemical deoxidation is carried out according to the following steps:

[0048] Step 1: Mix the ingredients

[0049] Titanium dioxide powder and vanadium pentoxide powder are placed in an oven and dried at 150° C. for 24 hours to obtain dried titanium dioxide powder and vanadium pentoxide powder; the dried titanium dioxide powder and vanadium pentoxide powder are mixed with aluminum powder and magnesium powder, wherein: the mass of vanadium pentoxide and titanium dioxide is converted according to the content of vanadium and titanium in the TC4 component and then added; the mass of magnesium powder is calculated according to the molar ratio of Mg:TiO2=1.2:1 and Mg:V2O5=2.5:1 and then added; the mass of aluminum powder is added in an excess of 10% according to the theoretical content of aluminum in the ideal product TC4 powder to obtain a mixed material;

[0050] Step 2: Self-propagating preparation of primary reduced TC4 powder

[0051] The mixed material is pressed at 10 MPa to obtain a block billet, the block billet of the mixed material is added into a self-propagating reactor, a self-propagating reaction is initiated by local ignition, and a self-propagating reaction product is obtained after the reaction material is cooled.

[0052] Step 3: Pickling primary reduction TC4 powder

[0053] The self-propagating reaction product is placed in a closed reactor, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product. The leaching temperature is 25° C., and the leaching time is 120 min. A filtrate and a leached product are obtained. The filtrate is removed, and the leached product is washed and vacuum-dried to obtain primary reduced TC4 powder with a median particle size of 21 μm. The molar concentration of hydrochloric acid is 1 mol / L, and the amount of dilute hydrochloric acid added to the self-propagating reaction product is a ratio of 10% excess hydrochloric acid required by the reaction theory, and the oxygen flow rate during the pickling process is 0.15 L / min.

[0054] Step 4: Primary reduction TC4 powder electrochemical deoxidation

[0055] The TC4 powder was loosely packed and placed in a pure titanium mesh of 100-200 mesh as the cathode, and a high-purity graphite rod was used as the anode, and electrochemical deoxidation was carried out in CaCl2 molten salt. During the electro-deoxidation reaction, the cathode and the electrolyte were placed in a closed resistance furnace. The electro-deoxidation process was protected by argon at a flow rate of 0.5L / min, the applied voltage was 3.3V, the reaction temperature was 1000℃, and the reaction time was 12h. After the reaction was completed, the cathode product cooled to room temperature was taken out of the resistance furnace.

[0056] Step 5: Washing the electrochemical deoxidation product

[0057] The cathode product after electrochemical deoxidation is placed in a closed reactor, and the cathode product in the above step 3 is washed in the order of deionized water, hydrochloric acid (1 mol / L), methanol-ethanol-propanol, and deionized water. After vacuum drying, high-quality TC4 powder with ultra-low oxygen content is obtained, wherein the oxygen content in the TC4 powder is less than 0.1wt%, and the median particle size is 29μm.

[0058] Example 3

[0059] A method for preparing ultra-low oxygen content titanium powder by primary reduction-electrochemical deoxidation is carried out according to the following steps:

[0060] Step 1: Mix the ingredients

[0061] Titanium dioxide powder and vanadium pentoxide powder are placed in an oven and dried at 150° C. for 24 hours to obtain dried titanium dioxide powder and vanadium pentoxide powder; the dried titanium dioxide powder and vanadium pentoxide powder are mixed with aluminum powder and magnesium powder, wherein: the mass of vanadium pentoxide and titanium dioxide is added according to the content of vanadium and titanium in the TC4 component, the mass of magnesium powder is calculated according to the molar ratio of Mg:TiO2=1.5:1 and Mg:V2O5=2.5:1 and then added, and the mass of aluminum powder is added in excess of 10% of the theoretical content of aluminum in the ideal product TC4 powder to obtain a mixed material;

[0062] Step 2: Self-propagating preparation of primary reduced TC4 powder

[0063] The mixed material is pressed at 10 MPa to obtain a block billet, the block billet of the mixed material is added into a self-propagating reactor, a self-propagating reaction is initiated by local ignition, and a self-propagating reaction product is obtained after the reaction material is cooled.

[0064] Step 3: Pickling primary reduction TC4 powder

[0065] The self-propagating reaction product is placed in a closed reactor, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product. The leaching temperature is 25° C., and the leaching time is 120 min. A filtrate and a leached product are obtained. The filtrate is removed, and the leached product is washed and vacuum-dried to obtain primary reduced TC4 powder with a median particle size of 18 μm. The molar concentration of hydrochloric acid is 1 mol / L, and the amount of dilute hydrochloric acid added to the self-propagating reaction product is a ratio of 10% excess hydrochloric acid required by the reaction theory, and the oxygen flow rate during the pickling process is 0.15 L / min.

[0066] Step 4: Primary reduction TC4 powder electrochemical deoxidation

[0067] The TC4 powder was loosely packed and placed in a pure titanium mesh of 100-200 mesh as the cathode, and a high-purity graphite rod was used as the anode, and electrochemical deoxidation was carried out in CaCl2 molten salt. During the electro-deoxidation reaction, the anode and cathode and the electrolyte were placed in a closed resistance furnace. The electro-deoxidation process was protected by argon at a flow rate of 0.2L / min, the applied voltage was 3.3V, the reaction temperature was 1050℃, and the reaction time was 12h. After the reaction was completed, the cathode product cooled to room temperature was taken out of the resistance furnace.

[0068] Step 5: Washing the electrochemical deoxidation product

[0069] The cathode product after electrochemical deoxidation is placed in a closed reactor, and the cathode product in the above step 3 is washed in the order of deionized water, hydrochloric acid (1 mol / L), methanol-ethanol, and deionized water. After vacuum drying, high-quality TC4 powder with ultra-low oxygen content is obtained, wherein the oxygen content in the TC4 powder is less than 0.1wt%, and the median particle size is 29μm.

[0070] Example 4

[0071] A method for preparing ultra-low oxygen content titanium powder by primary reduction-electrochemical deoxidation is carried out according to the following steps:

[0072] Step 1: Mix the ingredients

[0073] Titanium dioxide powder and vanadium pentoxide powder are placed in an oven and dried at 150° C. for 24 hours to obtain dried titanium dioxide powder and vanadium pentoxide powder; the dried titanium dioxide powder and vanadium pentoxide powder are mixed with aluminum powder and magnesium powder, wherein: the mass of vanadium pentoxide and titanium dioxide is converted according to the content of vanadium and titanium in the TC4 component and then added; the mass of magnesium powder is calculated according to the molar ratio of Mg:TiO2=1.2:1 and Mg:V2O5=2.5:1 and then added; the mass of aluminum powder is added in an excess of 10% according to the theoretical content of aluminum in the ideal product TC4 powder to obtain a mixed material;

[0074] Step 2: Self-propagating preparation of primary reduced TC4 powder

[0075] The mixed material is pressed at 10 MPa to obtain a block billet, the block billet of the mixed material is added into a self-propagating reactor, and a self-propagating reaction is initiated by local ignition. After the reaction material is cooled, a self-propagating reaction product is obtained.

[0076] Step 3: Pickling primary reduction TC4 powder

[0077] The self-propagating reaction product is placed in a closed reactor, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product. The leaching temperature is 25° C., and the leaching time is 120 min. A filtrate and a leached product are obtained. The filtrate is removed, and the leached product is washed and vacuum-dried to obtain primary reduced TC4 powder with a median particle size of 21 μm. The molar concentration of hydrochloric acid is 1 mol / L, and the amount of dilute hydrochloric acid added to the self-propagating reaction product is a ratio of 10% excess hydrochloric acid required by the reaction theory, and the oxygen flow rate during the pickling process is 0.15 L / min.

[0078] Step 4: Primary reduction TC4 powder electrochemical deoxidation

[0079] The TC4 powder was loosely packed and placed in a pure titanium mesh of 100-200 mesh as the cathode, and a high-purity graphite rod was used as the anode, and electrochemical deoxidation was carried out in CaCl2 molten salt. During the electro-deoxidation reaction, the anode and cathode and the electrolyte were placed in a closed resistance furnace. The electro-deoxidation process was protected by argon at a flow rate of 0.1L / min, the applied voltage was 3.5V, the reaction temperature was 950℃, the reaction time was 12h, and after the reaction was completed, the cathode product cooled to room temperature was taken out of the resistance furnace.

[0080] Step 5: Washing the electrochemical deoxidation product

[0081] The cathode product after electrochemical deoxidation is placed in a closed reactor, and the cathode product in the above step 3 is washed in the order of deionized water, hydrochloric acid (1 mol / L), methanol-ethanol, and deionized water. After vacuum drying, high-quality TC4 powder with ultra-low oxygen content is obtained, wherein the oxygen content in the TC4 powder is less than 0.1wt%, and the median particle size is 29μm.

[0082] Example 5

[0083] A method for preparing ultra-low oxygen content titanium powder by primary reduction-electrochemical deoxidation is carried out according to the following steps:

[0084] Step 1: Mix the ingredients

[0085] Titanium dioxide powder and vanadium pentoxide powder are placed in an oven and dried at 150° C. for 24 hours to obtain dried titanium dioxide powder and vanadium pentoxide powder; the dried titanium dioxide powder and vanadium pentoxide powder are mixed with aluminum powder and magnesium powder, wherein: the mass of vanadium pentoxide and titanium dioxide is converted according to the content of vanadium and titanium in the TC4 component and then added; the mass of magnesium powder is calculated according to the molar ratio of Mg:TiO2=1.2:1 and Mg:V2O5=2.5:1 and then added; the mass of aluminum powder is added in an excess of 10% according to the theoretical content of aluminum in the ideal product TC4 powder to obtain a mixed material;

[0086] Step 2: Self-propagating preparation of primary reduced TC4 powder

[0087] The mixed material is pressed at 10 MPa to obtain a block billet, the block billet of the mixed material is added into a self-propagating reactor, and a self-propagating reaction is initiated by local ignition. After the reaction material is cooled, a self-propagating reaction product is obtained.

[0088] Step 3: Pickling primary reduction TC4 powder

[0089] The self-propagating reaction product is placed in a closed reactor, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product. The leaching temperature is 25° C., and the leaching time is 120 min. A filtrate and a leached product are obtained. The filtrate is removed, and the leached product is washed and vacuum-dried to obtain primary reduced TC4 powder with a median particle size of 21 μm. The molar concentration of hydrochloric acid is 1 mol / L, and the amount of dilute hydrochloric acid added to the self-propagating reaction product is a ratio of 10% excess hydrochloric acid required by the reaction theory, and the oxygen flow rate during the pickling process is 0.15 L / min.

[0090] Step 4: Primary reduction TC4 powder electrochemical deoxidation

[0091] The TC4 powder was loosely packed and placed in a pure titanium mesh of 100-200 mesh as the cathode, and a high-purity graphite rod was used as the anode, and electrochemical deoxidation was carried out in CaCl2 molten salt. During the electro-deoxidation reaction, the anode and cathode and the electrolyte were placed in a closed resistance furnace. The electro-deoxidation process was protected by argon at a flow rate of 0.2L / min, the applied voltage was 3.3V, the reaction temperature was 950℃, the reaction time was 8h, and after the reaction was completed, the cathode product cooled to room temperature was taken out of the resistance furnace.

[0092] Step 5: Washing the electrochemical deoxidation product

[0093] The cathode product after electrochemical deoxidation is placed in a closed reactor, and the cathode product in the above step 3 is washed in the order of deionized water, hydrochloric acid (1 mol / L), methanol-ethanol-propanol, and deionized water. After vacuum drying, high-quality TC4 powder with ultra-low oxygen content is obtained, wherein the oxygen content in the TC4 powder is less than 0.1wt%, and the median particle size is 29μm.

[0094] Although the present invention is disclosed in the form of embodiments, the embodiments are not intended to limit the present invention. Any person skilled in the art can make corresponding adjustments and modifications to the technical scheme of the present invention by using the methods in the embodiments without departing from the spirit of the present invention. Therefore, simple modifications, equivalent changes and modifications made to the above-mentioned embodiments according to the technical essence of the present invention, including simple replacement of metal oxide precursors, replacement of the molten salt system used, replacement of the primary reduction method of reducing metal oxides to their corresponding low-valent oxides, etc., do not deviate from the content of the technical scheme of the present invention in essence, and all belong to the protection scope of the technical scheme of the present invention.

Claims

1. A method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation, characterized in that: The following steps are involved: Step 1: Mix the ingredients The titanium dioxide powder, aluminum powder, vanadium pentoxide powder and magnesium powder are dried and mixed evenly to obtain a mixed powder; Step 2: Self-propagating preparation of primary reduced TC4 powder After the mixed powder is pressed into a block blank, it is added into a self-propagating reaction furnace to initiate a self-propagating reaction, and after the reaction material is cooled, a self-propagating reaction product is obtained; Step 3: Pickling primary reduction TC4 powder The self-propagating reaction product is placed in a reaction kettle, and hydrochloric acid is used as a leaching liquid to leach the self-propagating reaction product to obtain a filtrate and a leaching product, the filtrate is removed, and the leaching product is washed and vacuum-dried to obtain primary reduced TC4 powder; Step 4: Primary reduction TC4 powder electrochemical deoxidation The primary reduced TC4 powder after pickling is placed in a cathode basket as a cathode, and a graphite rod is used as an anode for electrochemical deoxidation in a CaCl2-based molten salt; Step 5: Washing the electrochemical deoxidation product The cathode product in step 4 is washed and vacuum dried to obtain TC4 powder with ultra-low oxygen content.

2. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In the step 1, in the mixed powder, the total amount of magnesium is calculated according to the molar ratio of magnesium to vanadium pentoxide of 2.5:1 and the molar ratio of magnesium to titanium dioxide of 1-1.5:1, and then added; the mass of vanadium pentoxide and titanium dioxide is added according to the content of vanadium and titanium in the TC4 component, and the mass of aluminum is added according to the content of aluminum in the TC4 component in excess of 10%.

3. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: The self-propagating reaction time in step 2 is 5 to 90 seconds.

4. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In the step 3, the leaching temperature is 20-60° C., the leaching time is 30-180 min, and the concentration of hydrochloric acid is 1-3 mol / L.

5. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In the step 3, oxygen is introduced during the leaching process to inhibit the adsorption of hydrogen by the leaching product, and the oxygen flow rate is greater than 0.1 L / min.

6. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In the step 4, the TC4 powder is placed in a cathode basket made of a pure titanium mesh of 100 to 200 meshes as a cathode, and the electro-deoxidation process is protected by argon at a flow rate of 0.1 to 1 L / min, the applied voltage is 3.3 to 3.8 V, the reaction temperature is 850 to 1050° C., and the deoxidation time is 8 to 12 h.

7. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In the step 4, the primary reduced TC4 powder is directly placed in a cathode basket for electrochemical deoxidation without being pressed into blocks, and the electrolyte is CaCl2 molten salt.

8. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In step 4, the oxygen content of the obtained TC4 powder with ultra-low oxygen content is less than 0.1 wt%.

9. The method for preparing ultra-low oxygen TC4 powder by primary reduction-electrochemical deoxidation according to claim 1, characterized in that: In the step 5, the cathode product is washed in the order of deionized water, hydrochloric acid, alcohol, and deionized water; the alcohol is one or more of methanol, ethanol, and propanol.

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