Self-circulation continuous electric deoxidation device and process

Abstract

The invention relates to a self-circulation continuous electric deoxidation device and process, and belongs to the technical field of smelting deoxidation. The device comprises an electrolytic tank, a solid-liquid thermal separation tank and a cathode basket, the electrolytic tank is arranged above the solid-liquid thermal separation tank, electrolyte molten salt, an anode material and the cathode basket are arranged in the electrolytic tank, a powdery electric deoxidation cathode material is placed in the cathode basket, the bottom of the cathode basket penetrates out of the tank bottom of the electrolytic tank, and the solid-liquid thermal separation tank is arranged above the cathode basket. An electromagnetic valve is arranged; the electrolytic bath is connected with the solid-liquid thermal separation tank through a circulating fused salt pipeline, and a circulating pump is arranged on the pipeline. According to the self-circulation continuous electric deoxidation device and process, continuous operation of electrochemical deoxidation of high-activity powder is achieved, and therefore the space time yield for limiting high-temperature fused salt electric deoxidation is remarkably increased.

Description

Technical Field

[0001] The invention belongs to the technical field of powder making in powder metallurgy process in the field of non-ferrous metal smelting, and specifically relates to a self-circulating continuous electric deoxidation device and process. 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. The application of titanium-based materials requires that the oxygen content in them is as low as possible. However, deoxidation of titanium and titanium alloys has always been a challenge in the field of titanium research.

[0003] Electrochemical deoxidation is a proven and efficient deoxidation method with the technical advantages of being green and low-cost. However, due to its process characteristics, the electrochemical deoxidation method has difficulties in processing large quantities of materials. Therefore, developing a device and process for preparing low-oxygen titanium powder by continuous electro-deoxidation is an effective means to improve production efficiency. Summary of the invention

[0004] The technical task of the present invention is to address the deficiencies of the above existing technologies. The present invention proposes a self-circulating continuous electro-deoxidation device and process to achieve continuous operation of electrochemical deoxidation of high-activity powders, thereby significantly improving the time-space yield of limiting high-temperature molten salt electro-deoxidation.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a self-circulating continuous electro-deoxidation device, comprising an electrolytic cell, a solid-liquid thermal separation cell, and a cathode basket, wherein an electrolytic cell is arranged above the solid-liquid thermal separation cell, wherein the electrolytic cell contains electrolyte molten salt, and is provided with anode material and a cathode basket, wherein the cathode basket is used to place powdered electro-deoxidation cathode material, wherein the bottom of the cathode basket passes through the bottom of the electrolytic cell, and is provided with a high-temperature solenoid valve; the high-temperature electrolytic cell is connected to the solid-liquid thermal separation cell through a circulating molten salt pipeline, and a circulating pump is provided on the pipeline.

[0006] Furthermore, a filter screen for solid-liquid thermal separation is provided on the inner wall of the solid-liquid thermal separation tank.

[0007] Furthermore, the bottom of the cathode basket is funnel-shaped.

[0008] Furthermore, the electrolytic cell is a closed structure, connected to a gas purification circulation system, and the gas purification circulation system is used to achieve purification and circulation of the gas in the continuous electric deoxidation device.

[0009] Furthermore, the temperature in the electrolytic cell is raised by external resistance heating.

[0010] A self-circulating continuous electro-deoxidation process based on the above device comprises the following steps:

[0011] Step 1: Self-circulating continuous electro-deoxidation

[0012] The electrolyte molten salt is placed in the electrolytic cell. After the reaction temperature reaches above the melting point of the molten salt system for 30 minutes, the raw material to be deoxidized is added to the cathode basket for electrochemical deoxidation. After the electro-deoxidation process is completed, the deoxidation product and the molten salt are thermally separated by a self-circulating continuous electro-deoxidation device.

[0013] Step 2: Electrochemical deoxidation product washing

[0014] The deoxygenated product is washed with deionized water, dilute hydrochloric acid, mixed alcohol and deionized water in sequence, and low-oxygen titanium powder is obtained after filtering and drying.

[0015] Furthermore, the raw material to be deoxidized in step 1 is powder of high-oxygen titanium or high-oxygen titanium alloy, or powder of high-oxygen titanium or high-oxygen titanium alloy waste.

[0016] Furthermore, the electrolyte molten salt is CaCl2 or one or more mixed molten salts of CaCl2-CaO, CaCl2-NaCl, CaCl2-MgCl2, CaCl2-KCl, and CaCl2-NaCl-KCl.

[0017] Furthermore, in the step 1, the self-continuous cycle electro-deoxidation process is: first, the temperature of the device is increased to a state where the electrolyte is completely molten, and then the raw material to be deoxidized is placed in a cathode basket with a high-temperature solenoid valve at the bottom for electrochemical deoxidation. The potential used is 3.5 to 3.8 V, the reaction temperature is 850 to 950° C., and the reaction time is 8 to 24 hours to ensure that low-oxygen titanium powder is obtained; after the electro-deoxidation process is completed, the high-temperature solenoid valve at the bottom of the cathode basket is opened to achieve thermal separation of the deoxidized titanium powder and the molten salt.

[0018] Furthermore, the process also includes: passing the gas generated by the anode (mainly chlorine) into a gas purification circulation system to remove carbon oxides and possible water vapor therein, and then passing it into the electrolytic cell to eliminate a small amount of CaO remaining in the electrolyte, thereby achieving the purification and reuse of the molten salt.

[0019] Furthermore, the process also includes: taking out the deoxidized titanium powder separated by the solid-liquid thermal separation tank and placing it in an isolation chamber for cooling; at the same time, returning the molten salt in the solid-liquid thermal separation tank to the electrolytic cell through a circulation pump; and continuing to add deoxidized raw materials at a constant speed to the upper part of the cathode basket for electro-deoxidation, thereby realizing self-circulating continuous electrochemical deoxidation of the deoxidized raw materials.

[0020] Furthermore, the oxygen content of the low-oxygen titanium powder obtained by the process is less than 0.10wt%.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention proposes a self-circulating continuous electro-deoxidation device and process to realize the continuous operation of electrochemical deoxidation of high-activity powders. The present invention uses a directional circulating reaction gas flow to efficiently utilize chlorine in the electro-deoxidation process to achieve the purification of molten salt and the self-circulation and continuity of the electro-deoxidation process. Titanium powder can be continuously prepared through the self-circulating continuous electro-deoxidation process and device, and the oxygen content is less than 0.1wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of a self-circulating continuous electric deoxidation device;

[0024] Among them: 1-electrolytic cell; 2-solid-liquid thermal separation tank, 3-cathode basket; 4-electrolyte molten salt; 5-anode material; 6-high-temperature solenoid valve; 7-circulating molten salt pipeline; 8-circulating pump; 9-filter; 10-gas purification circulation system. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In the following embodiments, the purity of calcium chloride used is ≥96%, and the power supply used for the electric deoxidation is a high-frequency DC power supply.

[0026] The following examples use a device for preparing low-oxygen titanium powder through continuous electro-deoxidation. Figure 1 .

[0027] Example 1

[0028] A self-circulating continuous electric deoxidation device, such as Figure 1 As shown, it includes an electrolytic cell 1, a solid-liquid thermal separation cell 2, and a cathode basket 3. The electrolytic cell 1 is arranged above the solid-liquid thermal separation cell 2. The electrolytic cell 1 contains an electrolyte molten salt 4, and is provided with an anode material 5 and a cathode basket 3. The cathode basket 3 is used to place powdered electro-deoxidation cathode material. The bottom of the cathode basket passes through the bottom of the electrolytic cell and is provided with a high-temperature solenoid valve 6. The electrolytic cell 1 is connected to the solid-liquid thermal separation cell 2 through a circulating molten salt pipeline 7, and a circulating pump 8 is provided on the pipeline.

[0029] Wherein, a filter screen 9 for solid-liquid thermal separation is provided on the inner wall of the solid-liquid thermal separation tank.

[0030] Wherein, the bottom of the cathode basket is funnel-shaped.

[0031] Wherein, the temperature in the electrolytic cell is raised by external resistance heating.

[0032] The electrolytic cell is a closed structure, connected to a gas purification circulation system 10, and the gas purification circulation system 10 is used to purify and circulate the gas in the continuous electric deoxidation device.

[0033] The gas purification circulation system comprises a gas circulation pump, an argon gas cylinder, a chlorine gas purifier, a dryer and a circulation pipeline; the gas circulation pump, the chlorine gas purifier and the dryer are connected in sequence to form a circulation pipeline, and the two ends of the circulation pipeline are respectively connected to the gas inlet and outlet of the electrolytic cell; the argon gas cylinder is connected to the circulation pipeline, and whether the argon gas enters the circulation pipeline is controlled by the argon gas cylinder switch; before electrolysis, the argon gas cylinder is opened, and argon gas is introduced into the electrolytic cell to achieve an inert atmosphere condition. After the electrolysis starts, the argon gas cylinder switch can be closed and no gas is introduced because gas circulation is required; the chlorine gas purifier is used to remove carbon oxides in the anode gas, and the dryer is used to remove water vapor that may be generated in the electrolytic cell; the gas circulation pump is a vacuum pump for gas circulation, with an inlet and an outlet suction nozzle and an exhaust nozzle, and can continuously form a vacuum or negative pressure at the inlet; a slight positive pressure is formed at the exhaust nozzle; the working medium is mainly gas, and it is a small instrument for gas circulation.

[0034] Example 2

[0035] A self-circulating continuous electro-deoxidation process based on the device described in Example 1 is carried out in the following steps:

[0036] Step 1: Self-circulating continuous electrochemical deoxidation

[0037] 1000 g of dried CaCl2 was placed in the electrolytic cell. After the reaction temperature reached above the melting point of the molten salt system for 30 min, the molten salt system was pre-electrolyzed at a potential of 2.7 V for 2 h using a graphite rod as an anode and a cathode basket as a cathode. x＜1 The powder is continuously placed into the cathode basket at a speed of 0.1 g / min, and a graphite rod is used as the anode for electrochemical deoxidation under a circulating protective gas flow. The protective gas is argon, the argon flow rate is 0.3 L / min, the set potential of the high-frequency DC power supply is 3.6 V, the reaction temperature is 850 ° C, and the reaction time is 8 hours. After the reaction signal generated by the electrochemical device determines that the electro-deoxidation process is completed, the high-temperature solenoid valve of the electrolytic cell is opened to achieve thermal separation of the deoxidized titanium powder and the molten salt, and at the same time, the anode gas (mainly chlorine) treated by the gas purification circulation system is introduced into the electrolytic cell to eliminate a small amount of CaO remaining in the electrolyte, thereby achieving the purification and reuse of the molten salt. The thermally separated deoxidized titanium powder is taken out and placed in an isolation bin for cooling. At the same time, the molten salt in the separation tank is returned to the electrolytic cell through a circulation pump, and continues to be lowered into the cathode basket at a constant speed at the upper part of the silo for electro-deoxidation.

[0038] Step 2: Washing of the electro-deoxidation product

[0039] The deoxygenated product is washed with deionized water, dilute hydrochloric acid, mixed alcohol and deionized water in sequence, filtered and dried to obtain low-oxygen titanium powder, the oxygen content of which is less than 0.1 wt%.

[0040] Example 3

[0041] A self-circulating continuous electro-deoxidation process based on the device described in Example 1 is carried out in the following steps:

[0042] Step 1: Self-circulating continuous electrochemical deoxidation

[0043] 1000g of dried CaCl2-NaCl mixed molten salt was placed in an electrolytic cell. After the reaction temperature reached above the melting point of the molten salt system for 30 minutes, a graphite rod was used as an anode and a cathode basket was used as a cathode. The molten salt system was pre-electrolyzed at a potential of 2.7V for 2h. TC4 alloy powder with an oxygen content of 8.9wt% was continuously placed in the cathode basket at a speed of 0.1g / min. A graphite rod was used as an anode. Electrochemical deoxidation was performed under a circulating protective gas flow. The protective gas was argon. The argon gas flow rate was 0.3L / min. The set potential of the high-frequency DC power supply was 3.5V. The reaction temperature The temperature is 950℃ and the reaction time is 12h. After the reaction signal generated by the electrochemical device determines that the electro-deoxidation process is over, the high-temperature solenoid valve of the electrolytic cell is opened to achieve thermal separation of the deoxidized titanium powder and the molten salt. At the same time, the anode gas (mainly chlorine) treated by the gas purification circulation system is introduced into the electrolytic cell to eliminate the small amount of CaO remaining in the electrolyte and realize the purification and reuse of the molten salt. The thermally separated deoxidized titanium powder is taken out and placed in an isolation bin for cooling. At the same time, the molten salt in the separation tank is returned to the electrolytic cell through a circulation pump and continues to be lowered into the cathode basket at a constant speed at the upper part of the silo for electro-deoxidation.

[0044] Step 2: Washing of the electro-deoxidation product

[0045] The deoxidized product is washed with deionized water, dilute hydrochloric acid, mixed alcohol and deionized water in sequence, filtered and dried to obtain low-oxygen TC4 alloy powder, wherein the oxygen content of the TC4 alloy powder is less than 0.1 wt%.

[0046] Example 4

[0047] A self-circulating continuous electro-deoxidation process based on the device described in Example 1 is carried out in the following steps:

[0048] Step 1: Self-circulating continuous electrochemical deoxidation

[0049] 1000g of dried CaCl2 molten salt is placed in an electrolytic cell. After the reaction temperature reaches above the melting point of the molten salt system for 30 minutes, a graphite rod is used as an anode and a cathode basket is used as a cathode. The molten salt system is pre-electrolyzed at a potential of 2.7V for 2 hours. HDH titanium powder with an oxygen content of 3.5wt% is continuously placed in the cathode basket at a speed of 0.1g / min. A graphite rod is used as an anode. Electrochemical deoxidation is performed under a circulating protective gas flow. The protective gas is argon gas with an argon gas flow rate of 0.3L / min. The set potential of the high-frequency DC power supply is 3.7V, and the reaction temperature is 950℃. , the reaction time is 24h; after judging that the electric deoxidation process is over through the reaction signal generated by the electrochemical device, the high-temperature solenoid valve of the electrolytic cell is opened to realize the thermal separation of the deoxidized titanium powder and the molten salt, and at the same time, the anode gas (mainly chlorine) treated by the gas purification circulation system is introduced into the electrolytic cell to eliminate the small amount of CaO remaining in the electrolyte, so as to realize the purification and reuse of the molten salt; the thermally separated deoxidized titanium powder is taken out and placed in the isolation bin for cooling, and at the same time, the molten salt in the separation tank is returned to the electrolytic cell through the circulation pump, and continues to be lowered into the cathode basket at a constant speed at the upper part of the silo for electric deoxidation.

[0050] Step 2: Washing of the electro-deoxidation product

[0051] The deoxygenated product is washed with deionized water, dilute hydrochloric acid, mixed alcohol and deionized water in sequence, filtered and dried to obtain low-oxygen titanium powder, the oxygen content of which is less than 0.1 wt%.

[0052] The above technical scheme explains the technical idea of ​​the present invention, which cannot be used to limit the protection scope of the present invention. Any changes and modifications made to the above technical scheme based on the technical essence of the present invention without departing from the content of the technical scheme of the present invention shall fall within the protection scope of the technical scheme of the present invention.

Claims

1. A self-circulating continuous electric deoxidation device, characterized in that: It includes an electrolytic cell, a solid-liquid thermal separation cell, and a cathode basket. An electrolytic cell is arranged above the solid-liquid thermal separation cell. The electrolytic cell contains electrolyte molten salt, and is provided with anode materials and a cathode basket. The cathode basket is used to place powdered electro-deoxidation cathode materials. The bottom of the cathode basket passes through the bottom of the electrolytic cell and is provided with a high-temperature solenoid valve. The electrolytic cell is connected to the solid-liquid thermal separation cell through a circulating molten salt pipeline, and a circulating pump is provided on the pipeline.

2. A self-circulating continuous electric deoxidation device according to claim 1, characterized in that: A filter screen for solid-liquid thermal separation is provided on the inner wall of the solid-liquid thermal separation tank.

3. A self-circulating continuous electric deoxidation device according to claim 1, characterized in that: The bottom of the cathode basket is funnel-shaped.

4. A self-circulating continuous electric deoxidation device according to claim 1, characterized in that: The electrolytic cell is a closed structure and is connected to a gas purification circulation system, and the gas purification circulation system is used to realize the purification and circulation of the gas in the continuous electric deoxidation device.

5. The self-circulating continuous electric deoxidation device according to claim 1, characterized in that: The temperature in the electrolytic cell is raised by external resistance heating.

6. A self-circulating continuous electro-deoxidation process according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Self-circulating continuous electro-deoxidation The electrolyte molten salt is placed in the electrolytic cell, and after the reaction temperature reaches above the melting point of the molten salt system for 30 minutes, the raw material to be deoxidized is added to the cathode basket for electrochemical deoxidation; After the electric deoxidation process is completed, the thermal separation of the deoxidation product and the molten salt is achieved through a self-circulating continuous electric deoxidation device; Step 2: Electrochemical deoxidation product washing The deoxygenated product is washed with deionized water, dilute hydrochloric acid, mixed alcohol and deionized water in sequence, and low-oxygen titanium powder is obtained after filtering and drying.

7. A self-circulating continuous electro-deoxidation process according to claim 6, characterized in that: In the step 1, the raw material to be deoxidized is powder of high-oxygen titanium or high-oxygen titanium alloy, or powder of high-oxygen titanium or high-oxygen titanium alloy waste.

8. A self-circulating continuous electro-deoxidation process according to claim 6, characterized in that: In the step 1, the electrolyte is CaCl2 or one or more mixed molten salts of CaCl2-CaO, CaCl2-NaCl, CaCl2-MgCl2, CaCl2-KCl, and CaCl2-NaCl-KCl.

9. A self-circulating continuous electro-deoxidation process according to claim 6, characterized in that: In the step 1, the self-continuous cycle electro-deoxidation process is: first, the temperature of the device is increased to a state where the electrolyte is completely molten, and then the raw material to be deoxidized is placed in a cathode basket with a high-temperature solenoid valve at the bottom for electrochemical deoxidation. The potential used is 3.5 to 3.8 V, the reaction temperature is 850 to 950° C., and the reaction time is 8 to 24 hours. After the electro-deoxidation process is completed, the high-temperature solenoid valve at the bottom of the cathode basket is opened to achieve thermal separation of the deoxidized titanium powder and the molten salt.

10. A self-circulating continuous electro-deoxidation process according to claim 6, characterized in that: The process also includes: passing the gas generated by the anode into a gas purification circulation system to remove carbon oxides and water vapor therein, and then passing it into the electrolytic cell; The process also includes: taking out the deoxidized titanium powder separated by the solid-liquid thermal separation tank and placing it in an isolation chamber for cooling; at the same time, returning the molten salt in the solid-liquid thermal separation tank to the electrolytic cell through a circulation pump; and continuing to add deoxidized raw materials at a constant speed to the upper part of the cathode basket for electro-deoxidation, thereby realizing self-circulating continuous electrochemical deoxidation of the deoxidized raw materials.

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