Low-chlorine-content titanium sponge and its preparation method and device

Abstract

This application discloses a low-chlorine-content sponge titanium and its preparation method and apparatus. The preparation method includes: placing a titanium rod in liquid magnesium, adding titanium tetrachloride, carrying out a reduction reaction, removing the titanium rod, and performing vacuum distillation; the vacuum distillation time is ≥10h / t-Ti, and the condensation temperature during vacuum distillation is ≤350℃; when the cooling water is turned off, the condensation temperature shows a decreasing trend, and the temperature decrease rate is ≥3℃ / h, the distillation endpoint is determined: the vacuum is stopped, and after 10 minutes, the H volatilization pressure rise rate is calculated. When the H volatilization pressure rise rate is ≤0.3Pa / min, the vacuum distillation is stopped; H volatilization pressure rise rate = L2 pressure rise rate - L1 leakage rate. This application reduces the volatilization resistance of Mg / MgCl2 in the pores of sponge titanium by increasing volatilization channels in liquid magnesium; in addition, it proposes to adopt a composite method to determine the endpoint of vacuum distillation, so as to achieve the production of sponge titanium with low chloride impurity content.

Description

Technical Field

[0001] This application relates to the field of sponge titanium production, and more particularly to a low-chlorine-content sponge titanium and its preparation method and apparatus. Background Technology

[0002] Sponge titanium is generally prepared using the magnesiothermal reduction vacuum distillation method. The purpose of vacuum distillation is to separate residual Mg and MgCl2 from titanium in the sponge titanium agglomerate. To obtain sponge titanium products with low chlorine impurity content under the most efficient production conditions, precise control of the vacuum distillation endpoint is necessary. Current methods primarily employ a comprehensive assessment of production data to determine the vacuum distillation endpoint. This involves establishing a correlation between distillation time and chlorine impurities through industrial testing, and controlling the distillation endpoint within the distillation time period corresponding to furnaces with lower chlorine impurity levels. Due to variations in the airtightness of vacuum distillation equipment and the pumping capacity of vacuum units, over-distillation and incomplete distillation often occur, ultimately leading to adverse consequences such as increased chlorine impurity content and increased distillation energy consumption.

[0003] Therefore, developing a preparation method for producing sponge titanium with low chlorine impurity content is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, this application provides a method for preparing sponge titanium with low chlorine content, which achieves the production of sponge titanium with low chlorine impurity content by adding volatilization channels into the titanium agglomerate and using a composite method to determine the endpoint of vacuum distillation.

[0005] This application provides a method for preparing low-chlorine content sponge titanium, comprising:

[0006] The titanium rod was placed in liquid magnesium, titanium tetrachloride was added to carry out the reduction reaction, the titanium rod was removed and vacuum distilled.

[0007] Vacuum distillation time ≥ 10 h / t-Ti, condensation temperature during vacuum distillation ≤ 350℃; when the cooling water is turned off, the condensation temperature shows a decreasing trend, and the temperature decrease rate ≥ 3℃ / h, the distillation endpoint is determined.

[0008] Stop the vacuum, and calculate the H volatilization pressure rise rate after 10 minutes. Stop the vacuum distillation when the H volatilization pressure rise rate is ≤0.3Pa / min.

[0009] L1 leakage rate = (pressure value after 10 minutes of leakage rate test - ultimate vacuum) / 10; L2 pressure rise rate = (pressure value after 10 minutes of vacuum stop - initial pressure value) / 10;

[0010] H evaporation pressure rise rate = L2 pressure rise rate - L1 leakage rate.

[0011] In some specific implementations, the diameter of the titanium rod is 100mm to 300mm, the distance between the titanium rod and the bottom of the liquid magnesium is 0mm to 50mm, and the titanium rod is made of titanium alloy.

[0012] In some specific implementations, when the H volatilization pressure rise rate is >0.3 Pa / min, the vacuum is turned on for vacuum distillation for 4 to 6 hours, and then the vacuum is stopped to calculate the H volatilization pressure rise rate.

[0013] In some specific implementations, the reduction reaction is carried out under the protection of an inert gas, including argon, and the pressure of the reduction reaction is from 3 kPa to 25 kPa.

[0014] In some specific implementations, the vacuum distillation time is 80h to 150h.

[0015] This application also provides a low-chlorine-content sponge titanium, which is prepared according to the preparation method described above.

[0016] In some specific implementations, the chlorine impurity content in the low-chlorine content sponge titanium is 0.01 wt.% to 0.03 wt.%.

[0017] This application also provides an apparatus for preparing low-chlorine-content sponge titanium, comprising:

[0018] A distillation apparatus, the upper end of which is equipped with a vacuum gauge, and a distiller is provided inside the distillation apparatus. The distiller is equipped with a titanium rod and a partition, and the partition is located at the bottom of the distiller.

[0019] The condensing device is connected to the distillation device through a passage. A vacuum gauge is installed at the top of the condensing device, a condenser is installed inside the condensing device, a thermocouple is installed at the top of the condenser, a cooling water inlet is installed at the bottom of the condensing device, and a cooling water outlet is installed in the middle of the condensing device.

[0020] The vacuum unit includes a vacuum valve, a slide valve pump, and an oil booster pump. The vacuum unit is connected to the condensation device through a vacuum tube.

[0021] In some specific implementations, the residual Mg in the distillation apparatus is 1t to 6t, and the residual magnesium chloride in the distillation apparatus is 1t to 2t.

[0022] In some specific implementations, the vacuum unit includes a first vacuum valve, a second vacuum valve, a first slide valve pump, a second slide valve pump, and an oil booster pump connected in series, and the vacuum tube is connected to the first vacuum valve and the second vacuum valve respectively.

[0023] This application addresses the technical challenge of producing sponge titanium with low chlorine impurity content in titanium lumps of 10 tons or more. It proposes a method for preparing sponge titanium with low chlorine content by increasing volatilization channels within the titanium lump to reduce the volatilization resistance of Mg / MgCl2 in the pores of the sponge titanium. In addition, it proposes to adopt a composite method to determine the endpoint of vacuum distillation in order to achieve the production of sponge titanium with low chlorine impurity content. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the apparatus used in the embodiments of this application for preparing low-chlorine content sponge titanium. Detailed Implementation

[0025] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0026] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0027] It should be understood that the order of steps or the sequence of actions is not important as long as this application remains operational. Furthermore, two or more steps or actions may be performed simultaneously.

[0028] The use of any and all instances or exemplary language such as “e.g.” or “include” in this document is intended merely to better illustrate the application and does not constitute a limitation on the scope of the application. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of this application.

[0029] Furthermore, the numerical ranges and parameters used to define this application are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any numerical value inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise explicitly stated, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0030] This application provides a method for preparing low-chlorine content sponge titanium, comprising:

[0031] The titanium rod was placed in liquid magnesium, titanium tetrachloride was added to carry out the reduction reaction, the titanium rod was removed and vacuum distilled.

[0032] Vacuum distillation time ≥ 10 h / t-Ti, condensation temperature during vacuum distillation ≤ 350℃; when the cooling water is turned off, the condensation temperature shows a decreasing trend, and the temperature decrease rate ≥ 3℃ / h, the distillation endpoint is determined.

[0033] Stop the vacuum, and calculate the H volatilization pressure rise rate after 10 minutes. Stop the vacuum distillation when the H volatilization pressure rise rate is ≤0.3Pa / min.

[0034] L1 leakage rate = (pressure value after 10 minutes of leakage rate test - ultimate vacuum) / 10; L2 pressure rise rate = (pressure value after 10 minutes of vacuum stop - initial pressure value) / 10;

[0035] H evaporation pressure rise rate = L2 pressure rise rate - L1 leakage rate. This application first places a titanium rod in liquid magnesium, adds titanium tetrachloride, and carries out a reduction reaction. In some specific implementations, the amount of titanium tetrachloride added is up to a total of 40t. In some specific implementations, the diameter of the titanium rod is 100mm to 300mm, and can be 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 200mm, 220mm, 240mm, 260mm, 280mm, 290mm, or 300mm. The distance between the titanium rod and the bottom of the liquid magnesium is 0mm to 50mm, and can be 0mm, 10mm, 20mm, 30mm, 40mm, or 50mm. The titanium rod is made of titanium alloy. In some specific implementations, the reduction reaction is carried out under an inert gas atmosphere, including argon. The pressure of the reduction reaction is from 3 kPa to 25 kPa, and can be 3 kPa, 4 kPa, 5 kPa, 6 kPa, 8 kPa, 10 kPa, 12 kPa, 15 kPa, 18 kPa, 20 kPa, 22 kPa, 24 kPa, or 25 kPa. At the beginning of the reduction, a titanium alloy steel rod is inserted into the liquid magnesium; after the reduction is complete, it is removed. The channels formed by the titanium rod serve as volatilization channels for Mg / MgCl2 during the vacuum distillation stage. The titanium rod is inserted from the top, and its length is longer than the straight section of the reaction apparatus.

[0036] This application then removes the titanium rod, opens the vacuum valve of the condenser, and performs vacuum distillation. In some specific implementations, the pressure rise rate of the distillation apparatus is tested using the following method: First, all ports of the distillation apparatus are sealed with blind flanges, and then it is pressurized. When the gauge pressure reaches 30kPa~50kPa, the pressure drop rate is ≤0.2kPa / min. Then, the distillation apparatus is evacuated to the ultimate vacuum of 9Pa, and measured for 10 minutes. L1=(P1-P2) / 10, where P1 is the pressure after closing the front valve of the pump for 10 minutes (Pa); P2 is the ultimate vacuum (Pa); and L1 is in Pa / min.

[0037] In some specific implementations, the distillation endpoint is initially determined by the following conditions: distillation time ≥ 10 h / t-Ti, condenser temperature ≤ 350℃; when the cooling water of the condenser is turned off, the temperature of the thermocouple inside the condenser shows a decreasing trend, and the temperature decrease rate ≥ 3℃ / h; then, the distillation endpoint is finally determined by closing the vacuum valve at the condenser's extraction end, and the H volatilization pressure rise rate ≤ 0.3 Pa / min, indicating that the conditions are met for unloading; a second determination is made after 5 hours of distillation. Thereafter, a determination is made every 5 hours. L2 pressure rise rate = (P3 - P4) / 10, where P3 is the pressure 10 minutes after the vacuum pump's front-end valve is closed (Pa); P4 is the pressure at the start of the endpoint determination (Pa).

[0038] In some specific implementations, the vacuum distillation time is 80 h to 150 h. In some specific implementations, the residual Mg in the distillation apparatus is 1 t to 6 t, and the residual magnesium chloride in the distillation apparatus is 1 t to 2 t.

[0039] The method for preparing low-chlorine content sponge titanium is applicable to the production of titanium lumps in an 8-12 ton U-shaped furnace.

[0040] This application also provides a low-chlorine-content sponge titanium, which is prepared according to the preparation method described above.

[0041] In some specific implementations, the chlorine impurity content in the low-chlorine content sponge titanium is 0.01 wt.% to 0.03 wt.%.

[0042] This application also provides an apparatus for preparing low-chlorine-content sponge titanium, comprising:

[0043] A distillation apparatus, the upper end of which is equipped with a vacuum gauge, and a distiller is provided inside the distillation apparatus. The distiller is equipped with a titanium rod and a partition, and the partition is located at the bottom of the distiller.

[0044] The condensing device is connected to the distillation device through a passage. A vacuum gauge is installed at the top of the condensing device, a condenser is installed inside the condensing device, a thermocouple is installed at the top of the condenser, a cooling water inlet is installed at the bottom of the condensing device, and a cooling water outlet is installed in the middle of the condensing device.

[0045] The vacuum unit includes a vacuum valve, a slide valve pump, and an oil booster pump. The vacuum unit is connected to the condensation device through a vacuum tube.

[0046] In some specific implementations, the vacuum unit includes a first vacuum valve, a second vacuum valve, a first slide valve pump, a second slide valve pump, and an oil booster pump connected in series. The vacuum tube is connected to the first vacuum valve and the second vacuum valve, respectively. In some specific implementations, the low-vacuum pump is an H150 or H70 pump, preferably an H150 pump; the high-vacuum pump is an oil booster pump, Z-600 or Z-800, preferably Z-800 for a 10-ton U-shaped furnace. The vacuum pump is used as follows: when the condenser pressure is between atmospheric pressure and 50 Pa, the H150 pump is used for extraction; when the condenser pressure is ≤50 Pa, the high-vacuum unit is started, with the H150 pump used for initial extraction and the oil booster pump used as the secondary working pump. The magnesium chloride tube in the condensation unit is connected to the vacuum unit as a vacuum tube. In some specific implementations, the still is tested for air tightness before use, and the following methods are adopted: seal the still joint, purge the still with argon to 30 kPa, and after 10 minutes the pressure inside the still is ≥28 kPa; connect the still joint to the vacuum pump, and when the ultimate vacuum is below 9 Pa, close the front valve of the pump, and after 10 minutes the pressure of the still is ≤12 Pa.

[0047] The present application is further illustrated below with reference to embodiments. The scope of protection of the present application is not limited to the following embodiments.

[0048] Example 1

[0049] This embodiment provides a low-chlorine-content titanium sponge, and the apparatus for preparing the low-chlorine-content titanium sponge is as follows: Figure 1 As shown,

[0050] A distillation apparatus is provided with a vacuum gauge 101 at the upper end of the distillation apparatus and a distiller 102 inside the distillation apparatus. The distiller is provided with a titanium rod 103 and a partition 115, and the partition 115 is located at the bottom of the distiller 102.

[0051] A condensing device is connected to a distillation device via a passageway. A vacuum gauge 113 is provided at the top of the condensing device. A condenser 112 is provided inside the condensing device. A thermocouple 104 is provided at the top of the condenser 112. A cooling water inlet 111 is provided at the bottom of the condensing device. A cooling water outlet 110 is provided in the middle of the condensing device.

[0052] The vacuum unit includes a vacuum valve 106, a slide valve pump 108, a vacuum valve 107, a slide valve pump 109, and an oil booster pump 114. The vacuum unit is connected to a condensing device via a vacuum pipe 105. The slide valve pump 108 is connected between the vacuum valve 107 and the valve, and the booster pump 114 and the slide valve pump 109 are connected between the vacuum valve 106 and the valve.

[0053] The preparation method of the low-chlorine content sponge titanium includes:

[0054] A positive pressure test was performed on the still. The valve 107 at the front end of the still was closed, and the still 102 was purged with argon to 30 kPa. After 10 minutes, the pressure of the still was 29 kPa.

[0055] For the leak rate test of the distiller, before the vacuum distillation begins, the slide valve pump 108 is started to evacuate the distiller 102. When the vacuum degree of the evacuated distiller 102 is 9 Pa, the front valve 107 is closed. After 10 minutes, the pressure rises to 11 Pa. Then, the L1 leak rate is 0.2 Pa / min.

[0056] Liquid magnesium or magnesium ingots are added to distiller 102. Then, the liquid magnesium in the reactor is heated to 800°C. Titanium rod 103 with a diameter of 150 mm and 50 mm from the bottom is inserted into the reactor. Titanium tetrachloride is then added into the reactor. After the total amount of titanium tetrachloride added reaches 40 tons, the addition of titanium tetrachloride is stopped. Argon gas is introduced into the reactor and the pressure is controlled at 20 kPa. Titanium rod 103 is then extracted from the titanium ingot.

[0057] Connect the passage of the distiller 102 to the passage of the condenser 112, insert the vacuum gauge 101 into the distiller, insert the thermocouple 104 into the condenser 112, and connect the vacuum tube 105 to the vacuum unit.

[0058] Start vacuum pump 108 and vacuum valve 107 to evacuate condenser 112, and open condenser inlet valve 111 at the same time; use low vacuum pump 108 to evacuate 15 hours before distillation.

[0059] When the vacuum gauge at vacuum line 105 displays 20Pa, start vacuum pump 109 and oil booster pump 114, close vacuum valve 107, and open vacuum valve 106.

[0060] Vacuum distillation for 100 hours, condenser temperature 300℃. When the cooling water of the condenser is turned off, the temperature of the thermocouple inside the condenser terminal shows a downward trend, and the temperature drop rate is 5℃ / h; start the distillation endpoint determination.

[0061] Close the vacuum valve 106 at the condenser's extraction end and observe the pressure inside the distiller 102. After 10 minutes, the pressure inside the distiller increases from 5 Pa to 8 Pa. The L2 pressure rise rate of the distiller is 0.3 Pa / min, and the H evaporation pressure rise rate of the distiller is 0.1 Pa / min. Then, the vacuum distillation can be ended.

[0062] If the H volatilization pressure rise rate is greater than 0.3 Pa / min, repeat the previous step to determine the endpoint after 5 hours.

[0063] The chlorine content in the low-chlorine content sponge titanium is 0.02 wt.%.

[0064] Example 2

[0065] A positive pressure test was performed on the still. The valve 107 at the front end of the still was closed, and the still 102 was purged with argon to 35 kPa. After 10 minutes, the pressure of the still was 33 kPa.

[0066] For the leak rate test of the distiller, before the vacuum distillation begins, the slide valve pump 108 is started to evacuate the distiller 102. When the vacuum degree of the evacuated distiller 102 is 8 Pa, the front valve 107 is closed. After 10 minutes, the pressure rises to 9 Pa. Then, the L1 leak rate is 0.1 Pa / min.

[0067] Liquid magnesium or magnesium ingots are added to distiller 102. Then, the liquid magnesium in the reactor is heated to 800°C. Titanium rod 103 with a diameter of 300 mm and 200 mm from the bottom is inserted into the reactor. Titanium tetrachloride is then added to the reactor. After the total amount of titanium tetrachloride added reaches 40 tons, the addition of titanium tetrachloride is stopped. Argon gas is introduced into the reactor and the pressure is controlled at 3~25 kPa. Titanium rod 103 is then extracted from the titanium ingot.

[0068] Connect the passage of the distiller 102 to the passage of the condenser 112, insert the vacuum gauge 101 into the distiller, insert the thermocouple 104 into the condenser 112, and connect the vacuum tube 105 to the vacuum unit.

[0069] Start vacuum pump 108 and vacuum valve 107 to evacuate condenser 112, and open condenser inlet valve 111 at the same time; use low vacuum pump 108 to evacuate 15 hours before distillation.

[0070] When the vacuum gauge at vacuum line 105 displays 20Pa, start vacuum pump 109 and oil booster pump 114, close vacuum valve 107, and open vacuum valve 106.

[0071] Vacuum distillation for 100 hours, condenser temperature 340℃. When the cooling water of the condenser is turned off, the temperature of the thermocouple inside the condenser terminal shows a downward trend, and the temperature drop rate is 3℃ / h; start the distillation endpoint determination.

[0072] Close the vacuum valve 106 at the condenser's extraction end and observe the pressure inside the distiller 102. After 10 minutes, the pressure inside the distiller increases from 10 Pa to 13 Pa. The L2 pressure rise rate of the distiller is 0.3 Pa / min, and the H evaporation pressure rise rate of the distiller is 0.2 Pa / min. Then, the vacuum distillation can be ended.

[0073] If the H volatilization pressure rise rate is greater than 0.3 Pa / min, repeat the previous step to determine the endpoint after 5 hours.

[0074] The chlorine content in the low-chlorine content sponge titanium is 0.03 wt.%.

[0075] Comparative Example 1

[0076] A positive pressure test was performed on the still. The valve 107 at the front end of the still was closed, and the still 102 was purged with argon to 35 kPa. After 10 minutes, the pressure of the still was 34 kPa.

[0077] For the leak rate test of the distiller, before the vacuum distillation begins, the slide valve pump 108 is started to evacuate the distiller 102. When the vacuum degree of the evacuated distiller 102 is 5 Pa, the front valve 107 is closed. After 10 minutes, the pressure rises to 6 Pa. Then, the L1 leak rate is 0.1 Pa / min.

[0078] Liquid magnesium or magnesium ingots are added to distiller 102. Then, the liquid magnesium in the reactor is heated to 800°C. Titanium rod 103 with a diameter of 300 mm and 200 mm from the bottom is inserted into the reactor. Titanium tetrachloride is then added to the reactor. After the total amount of titanium tetrachloride added reaches 40 tons, the addition of titanium tetrachloride is stopped. Argon gas is introduced into the reactor and the pressure is controlled at 3~25 kPa. Titanium rod 103 is then extracted from the titanium ingot.

[0079] Connect the passage of the distiller 102 to the passage of the condenser 112, insert the vacuum gauge 101 into the distiller, insert the thermocouple 104 into the condenser 112, and connect the vacuum tube 105 to the vacuum unit.

[0080] Start vacuum pump 108 and vacuum valve 107 to evacuate condenser 112, and open condenser inlet valve 111 at the same time; use low vacuum pump 108 to evacuate 15 hours before distillation.

[0081] When the vacuum gauge at vacuum line 105 displays 20Pa, start vacuum pump 109 and oil booster pump 114, close vacuum valve 107, and open vacuum valve 106.

[0082] Vacuum distillation for 100 hours, condenser temperature 340℃. When the cooling water of the condenser is turned off, the temperature of the thermocouple inside the condenser terminal shows a downward trend, and the temperature drop rate is 3℃ / h; start the distillation endpoint determination.

[0083] Close the vacuum valve 106 at the condenser's extraction end and observe the pressure inside the distiller 102. After 10 minutes, the pressure inside the distiller increases from 8 Pa to 10 Pa. The L2 pressure rise rate of the distiller is 0.2 Pa / min, and the H evaporation pressure rise rate of the distiller is 0.1 Pa / min. Then, the vacuum distillation can be ended.

[0084] The chlorine content in the low-chlorine content sponge titanium is 0.015 wt.%.

[0085] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and application concept of this application, should be included within the scope of protection of this application.

Claims

1. A method for preparing low-chlorine-content sponge titanium, characterized in that, include: The titanium rod was placed in liquid magnesium, titanium tetrachloride was added to carry out the reduction reaction, the titanium rod was removed and vacuum distilled. Vacuum distillation time ≥ 10 h / t-Ti, condensation temperature during vacuum distillation ≤ 350℃; when the cooling water is turned off, the condensation temperature shows a decreasing trend, and the temperature decrease rate ≥ 3℃ / h, the distillation endpoint is determined. Stop the vacuum, and calculate the H volatilization pressure rise rate after 10 minutes. Stop the vacuum distillation when the H volatilization pressure rise rate is ≤0.3Pa / min. L1 leakage rate = (pressure value after 10 minutes of leakage rate test - ultimate vacuum) / 10; L2 pressure rise rate = (pressure value after 10 minutes of vacuum stop - initial pressure value) / 10; H evaporation pressure rise rate = L2 pressure rise rate - L1 leakage rate; When the H volatilization pressure rise rate is >0.3 Pa / min, vacuum distillation is performed for 4 to 6 hours, then vacuum pumping is stopped, and the H volatilization pressure rise rate is calculated.

2. The preparation method according to claim 1, characterized in that, The diameter of the titanium rod is 100mm to 300mm, the distance between the titanium rod and the bottom of the liquid magnesium is 0mm to 50mm, and the titanium rod is made of titanium alloy.

3. The preparation method according to claim 1, characterized in that, The reduction reaction is carried out under the protection of an inert gas, including argon, and the pressure of the reduction reaction is from 3 kPa to 25 kPa.

4. The preparation method according to claim 1, characterized in that, The vacuum distillation time is 80 to 150 hours.

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