Cold-state magnesium pre-adding process method for titanium sponge production

Abstract

The invention discloses a cold-state magnesium pre-adding process method for sponge titanium production in the field of chemical engineering, which comprises the following steps: S1, after cold-state magnesium adding and distillation are finished, cooling a reactor to be less than or equal to 45 DEG C, turning over and dismounting a lump-containing tank, adding a preset amount of solid magnesium ingot layer by layer through a vacuum channel of the reactor containing condensate, meanwhile, continuously filling argon into the reactor; s2, sealing and vacuumizing, installing a feeding pipe, and vacuumizing the reactor to form a negative pressure environment; s3, carrying out reduction low-temperature degassing, heating to a preset temperature, and maintaining the temperature for a preset time; s4, reducing the molten condensate, heating to a preset temperature, and maintaining for a preset time; s5, reduction charging is conducted, specifically, reduction reaction is conducted within the preset temperature range, and sponge titanium is generated; magnesium adding operation is carried out at a low temperature of less than or equal to 45 DEG C, so that the safety is improved, and the production cost is reduced by subsequent low-temperature degassing and reduction of melt condensate; and moreover, the cold magnesium addition under the protection of argon avoids the oxidation of magnesium ingots and residual low-valence titanium in the reactor.

Description

Technical Field

[0001] This invention relates to the chemical industry, and more particularly to a cold pre-magnesium addition process for the production of sponge titanium. Background Technology

[0002] The Kraul process (magnesium thermal reduction-vacuum distillation combined method) is the existing industrial method for producing sponge titanium. Depending on the company's production conditions, it is divided into full-process and semi-process production. Full-process production includes five main stages: high-titanium slag preparation, chlorination to crude titanium tetrachloride, refining to obtain refined titanium tetrachloride, magnesium reduction + distillation, and magnesium chloride electrolysis. Semi-process production only includes the magnesium reduction + distillation stage.

[0003] In the magnesium reduction and distillation process, magnesium, as a reducing agent, needs to be replenished online. Whether it is full-process production (when the electrolyte magnesium production is insufficient) or semi-process production, solid magnesium ingots need to be manually added in a high-temperature environment (above 500℃). Each furnace cycle takes 1-2 hours, which can easily lead to the following problems: First, the high-temperature environment can easily cause burns to operators; second, the manual high-temperature magnesium addition process may introduce impurities, resulting in substandard purity of sponge titanium; third, the magnesium addition cycle is long and energy consumption is high, affecting production capacity. Summary of the Invention

[0004] To overcome these shortcomings, the technical problem to be solved by this invention is: how to improve the quality, safety and energy consumption issues caused by adding magnesium under high temperature conditions.

[0005] The technical solution adopted by this invention to solve its technical problem is: The cold pre-magnesium addition process for the production of sponge titanium includes the following steps: S1: Add magnesium in a cold state. After distillation, cool the reactor to ≤45℃, turn it over and remove the container containing the lumps. Add the preset amount of solid magnesium ingots layer by layer through the vacuum channel of the reactor containing condensate, while continuously charging the reactor with argon gas. S2: Seal and vacuum the reactor, install the feed pipe, and create a negative pressure environment by evacuating the reactor. S3: Reduce low-temperature degassing, and maintain the preset temperature for a preset duration after heating to the preset temperature; S4: Reduce the molten solidified material, heat it to the preset temperature and maintain it for the preset time; S5: Reduction feeding, add... A reduction reaction is carried out within a preset temperature range to produce sponge titanium.

[0006] Furthermore, in step S1, the inner diameter of the reactor vacuum channel containing condensate is ≥150mm.

[0007] Furthermore, in step S1, argon gas is introduced into the reactor to maintain the gas pressure inside the reactor at 1.5 kPa-2.0 kPa.

[0008] Furthermore, in step S2, the vacuum level in the reactor is ≤-80 kPa.

[0009] Furthermore, in step S3, the temperature range is 300℃-500℃.

[0010] Furthermore, the duration of maintenance ranges from 3 to 5 hours.

[0011] Furthermore, in step S4, the temperature range is 750℃-850℃.

[0012] Furthermore, the duration of maintenance ranges from 8 to 10 hours.

[0013] Furthermore, in step S5, the temperature range is 750℃-830℃.

[0014] Furthermore, in step S1, a rainproof cover structure is installed on the reactor, and the rainproof cover structure is provided with a feeding channel that connects to the vacuum channel of the reactor.

[0015] The beneficial effects of this invention are: The magnesium addition operation is carried out at a lower temperature of ≤45℃, which completely avoids the risk of burns and fires caused by traditional high-temperature operations above 500℃, significantly improving the safety factor. Furthermore, the subsequent low-temperature degassing stage and reduction melting solidification stage are to avoid the energy consumption of maintaining high temperature for a long time when melting magnesium alone, thus reducing production costs. Moreover, the cold magnesium addition under argon protection effectively avoids the oxidation of magnesium ingots and residual low-valence titanium in the reactor, resulting in stable impurity content in the sponge titanium product that meets the standards. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the present invention; Detailed Implementation

[0017] The invention will be further described below with reference to the accompanying drawings.

[0018] like Figure 1 As shown, this invention proposes a cold pre-magnesium addition process for the production of sponge titanium, comprising the following steps: S1: Cold magnesium addition. After distillation, the reactor is cooled to ≤45℃, the container containing the lumps is inverted and removed, and a predetermined amount of solid magnesium ingots are added layer by layer through the vacuum channel of the reactor containing condensate, while argon gas is continuously introduced into the reactor. Lowering the reactor temperature ensures that the magnesium addition operation is performed at a lower temperature range, avoiding the burn and fire risks associated with traditional high-temperature operations above 500℃, significantly improving safety. Furthermore, adding magnesium layer by layer through the vacuum channel of the reactor containing condensate ensures a stable and controllable process, improving the accuracy of the addition amount. The inner diameter of the reactor vacuum channel is ≥150mm, ensuring stable passage of magnesium ingots during the addition process and preventing blockages.

[0019] Argon gas is continuously introduced into the reactor during magnesium addition to prevent the combustion of low-valence titanium in the condensate. Argon gas is introduced to maintain the pressure inside the reactor at 0 kPa-3 kPa, preferably 1.5 kPa-2.0 kPa in this embodiment, to ensure the best gas protection effect. 800 kg-3500 kg of magnesium ingots are added layer by layer through a vacuum channel. In the specific implementation process, the amount of magnesium ingots added is larger in the semi-process production process, while in the full-process production activities, the amount of magnesium ingots added is smaller, mainly to make up for the magnesium liquid shortage.

[0020] During the rainy season, the reactor should be equipped with a rainproof cover structure. The rainproof cover structure is equipped with a feeding channel that connects to the vacuum channel of the reactor. Specifically, the reactor cover should be installed first, and then magnesium ingots should be added through the feeding hole of the cover or a water basin to prevent rainwater from contacting the condensate and causing magnesium chloride hydrolysis or combustion.

[0021] S2: Seal and vacuum the reactor, install the feeding pipe, and create a negative pressure environment by evacuating the reactor. After adding magnesium ingots, process and seal the feeding pipe or feeding channel, and then evacuate the reactor to ensure that the vacuum degree in the reactor is ≤-80 kPa, thereby ensuring sufficient vacuum and improving product processing quality.

[0022] S3: Low-temperature degassing and heating to a preset temperature and maintaining it for a preset time; specifically, starting the heating system to slowly raise the internal temperature of the reactor to 300℃-500℃ and maintaining it at this temperature for 3h-5h, so that the moisture and gas adsorbed on the surface of the magnesium ingot are fully removed.

[0023] S4: Reduce the molten solids and heat them to a preset temperature and maintain the temperature for a preset time; specifically, continue heating to 750℃-850℃ and maintain the temperature for 8h-10h, using electrical energy to completely melt the added solid magnesium ingots to form liquid magnesium.

[0024] S5: Reduction feeding, add... A reduction reaction is carried out within a preset temperature range to produce sponge titanium; specifically, titanium tetrachloride (TiCl₂) is added to the reactor at a uniform rate. Meanwhile, the reaction temperature is controlled at 750℃-830℃ to carry out the reduction reaction, producing sponge titanium.

[0025] It should be noted that the magnesium addition operation is carried out at a lower temperature of ≤45℃, which completely avoids the risk of burns and fires caused by traditional high-temperature operations above 500℃, significantly improving the safety factor. Furthermore, the subsequent low-temperature degassing stage and reduction melting solidification stage are to avoid the energy consumption of maintaining high temperature for a long time when melting magnesium alone, thus reducing production costs. Moreover, the cold magnesium addition under argon protection effectively avoids the oxidation of magnesium ingots and residual low-valence titanium in the reactor, resulting in stable impurity content in the sponge titanium product that meets the standards.

[0026] Example 1 A semi-process titanium sponge manufacturer uses a 12-ton reactor (corresponding to bulk tank specifications) and needs to purchase magnesium ingots for production. Traditional high-temperature line magnesium addition is time-consuming and poses significant safety hazards.

[0027] S1: Cold addition of magnesium After a single furnace reduction-distillation operation, the reactor was cooled to 40°C, inverted, and the bulk container was removed. Inspection revealed that the vacuum channel naturally formed during the distillation process had a diameter of 165 mm.

[0028] Argon gas was continuously introduced into the reactor through the feed port to maintain a slightly positive pressure environment (approximately 1.5 kPa) and prevent air from entering. Subsequently, the operator added 2500 kg of solid magnesium ingots (in block form, each block weighing approximately 15 kg) layer by layer through the vacuum channel. The entire magnesium addition process was completed at room temperature and took approximately 12 minutes.

[0029] S2: Sealing and Evacuation Install and tighten the feed pipe, and evacuate the reactor system to a final vacuum level of -85 kPa.

[0030] S3: Low-temperature degassing Start the heating system to slowly raise the internal temperature of the reactor to 350°C and maintain this temperature for 4 hours to fully remove the moisture and gas adsorbed on the surface of the magnesium ingot.

[0031] S4: Molten condensate (molten magnesium) The temperature was raised to 800°C and maintained at this temperature for 9 hours. The added solid magnesium ingot was completely melted using electrical energy to form liquid magnesium.

[0032] S5: Reduction reaction Titanium tetrachloride (TiCl) was added to the reactor at a uniform rate. Meanwhile, the reaction temperature is controlled at 800℃ to carry out the reduction reaction, producing sponge titanium.

[0033] Results: In the plate-process production, the magnesium addition operation is carried out at a normal temperature of 40℃, completely avoiding the risks of burns and fires caused by traditional high-temperature operations above 500℃, significantly improving safety. The magnesium addition time is shortened from the traditional 1-2 hours to 12 minutes, increasing efficiency by approximately 10 times. Because pre-added magnesium ingots are used and melted in subsequent processes, the energy consumption of maintaining high temperatures for extended periods to melt magnesium alone is avoided, resulting in a reduction of approximately 12% in power consumption compared to the traditional method. Cold magnesium addition under argon protection effectively prevents the oxidation of magnesium ingots and residual low-valence titanium in the reactor, ensuring stable impurity content in the sponge titanium product that meets standards.

[0034] Example 2 A complete sponge titanium production enterprise (full-process production) has a magnesium electrolysis process, but the output of liquid magnesium per cycle is insufficient to meet the needs of a large reactor (18 tons), and magnesium ingots need to be added.

[0035] S1: Cold addition of magnesium After the reactor distillation was completed and cooled to ≤40℃, the bulk container was inverted and removed. The diameter of the vacuum channel was measured to be 170mm. Under the protection of continuous argon purging (pressure maintained at approximately 2.0 kPa), 1200kg of magnesium ingots were added to the reactor through the vacuum channel to make up for the current production shortfall of magnesium in the electrolyte.

[0036] S2: Sealing and Evacuation After sealing the reactor, a vacuum was drawn to -82 kPa.

[0037] S3: Low-temperature degassing The temperature is raised to 400℃ and held for 4.5 hours for deep degassing.

[0038] S4: Molten condensate (molten magnesium) Heat to 780°C and hold for 10 hours to ensure that the added magnesium ingots melt completely along with the previously present condensate.

[0039] S5: Reduction reaction join in The reduction reaction is carried out at 820℃.

[0040] Results: This method resolves the structural problem of mismatch between liquid magnesium supply and reduction demand in the entire production process, eliminating the need to extend production cycles by waiting for liquid magnesium to accumulate and improving equipment turnover. The "magnesium replenishment" operation is seamlessly integrated into the cooling phase between fixed reduction-distillation cycles, without occupying additional production line operating time, achieving efficient synergy with existing processes. Operation under argon protection ensures product quality; compared to stopping production to wait or using additional high-temperature furnaces for magnesium replenishment, this method significantly reduces the overall production cost per unit product.

Claims

1. A cold pre-magnesium addition process for the production of sponge titanium, characterized in that, Includes the following steps, S1: Add magnesium in a cold state. After distillation, cool the reactor to ≤45℃, turn it over and remove the container containing the lumps. Add the preset amount of solid magnesium ingots layer by layer into the vacuum channel of the reactor containing condensate, while continuously charging the reactor with argon gas. S2: Seal and vacuum the reactor, install the feed pipe, and create a negative pressure environment by evacuating the reactor. S3: Reduce low-temperature degassing, and maintain the preset temperature for a preset duration after heating to the preset temperature; S4: Reduce the molten solidified material, heat it to the preset temperature and maintain it for the preset time; S5: Reduction feeding, add... A reduction reaction is carried out within a preset temperature range to produce sponge titanium.

2. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S1, the inner diameter of the vacuum channel of the reactor containing condensate is ≥150mm.

3. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S1, argon gas is introduced into the reactor to maintain the gas pressure inside the reactor at 1.5 kPa-2.0 kPa.

4. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S2, the vacuum level in the reactor is ≤-80 kPa.

5. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S3, the temperature range is 300℃-500℃.

6. The cold pre-magnesium addition process for sponge titanium production according to claim 5, characterized in that, The duration of maintenance ranges from 3 to 5 hours.

7. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S4, the temperature range is 750℃-850℃.

8. The cold pre-magnesium addition process for sponge titanium production according to claim 7, characterized in that, The duration of maintenance ranges from 8 to 10 hours.

9. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S5, the temperature range is 750℃-830℃.

10. The cold pre-magnesium addition process for sponge titanium production according to claim 1, characterized in that, In step S1, a rainproof cover structure is installed on the reactor, and the rainproof cover structure is provided with a feeding channel that connects to the vacuum channel of the reactor.

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