A method for producing metallic vanadium

Abstract

The present application relates to the metallurgical field, and in particular to a preparation method of metallic vanadium. The preparation method of the present application uses calcium thermal method to prepare metallic vanadium, and a reduction reaction is carried out between calcium pyrovanadate and metallic calcium with a specific mass ratio, so that the reduction process is stable and controllable. Furthermore, the material is subjected to density screening before pickling, which improves the pickling efficiency and saves a large amount of acid. The process flow is safe, controllable, easy to operate and environmentally friendly. Tests show that the preparation method of the present application can realize stable and controllable reaction without additional coolant adjustment. The V content of the obtained metallic vanadium is greater than or equal to 99.0wt%, Fe is less than or equal to 0.08wt%, Si is less than or equal to 0.05wt%, C is less than or equal to 0.10wt%, N is less than or equal to 0.04wt%, O is less than or equal to 0.30wt%, and the total amount of Al, Ni, Cu, Nb, Mo, Co and Ag impurities is less than or equal to 0.03wt%.

Description

Technical Field

[0001] This invention relates to the field of metallurgy, specifically a method for preparing metallic vanadium. Background Technology

[0002] Vanadium is an important strategic metal resource with characteristics such as high melting point, good processing performance, strong corrosion resistance, and small fast neutron absorption cross section. It has been widely used in aerospace, steel, energy, nuclear power and other fields.

[0003] Currently, the main method for preparing metallic vanadium is the metallothermic reduction method, which involves first producing its pure oxide or chloride, and then reducing it with metals such as calcium, magnesium, and aluminum to obtain metallic vanadium. However, these methods are characterized by violent reactions, and some methods cannot produce metallic vanadium powder. Furthermore, even if metallic vanadium powder is obtained, pickling requires a large amount of acid, resulting in high costs and environmental problems. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing metallic vanadium. The preparation method provided by the present invention has a stable and controllable process, low acid consumption during acid washing, and high purity of the obtained metallic vanadium with low impurity content, especially low oxygen content.

[0005] This invention provides a method for preparing metallic vanadium, comprising the following steps:

[0006] S1) Under a protective gas atmosphere, calcium pyrovanadate with metallic calcium in a mass ratio of (1.46 to 1.59):1 undergoes a reduction reaction.

[0007] S2) Mix the reaction product obtained in step S1) with water and stir. Then, perform density sieving on the solid material obtained from the reaction and then acid washing to obtain metallic vanadium.

[0008] This invention first involves a reduction reaction of calcium pyrovanadate and metallic calcium in a mass ratio of (1.46–1.59):1 under a protective gas atmosphere. Specifically, the calcium pyrovanadate and metallic calcium in a mass ratio of (1.46–1.59):1 are mixed and placed in a protective gas atmosphere, followed by the reduction reaction. The reduction reaction of this invention specifically involves: first heating to a first temperature at a heating rate of 8°C / min–10°C / min, and then heating to the reduction reaction temperature at a heating rate of 4°C / min–6°C / min; the first temperature is less than 600°C. The temperature of the reduction reaction in this invention is 680°C–700°C, and the time of the reduction reaction is 40 min–60 min. In some embodiments of the present invention, calcium pyrovanadate and metallic calcium are mixed in a mass ratio of (1.46–1.59):1 and placed in a protective gas atmosphere. The mixture is first heated to a first temperature at a heating rate of 8–10 °C / min, and then heated to the temperature of the reduction reaction at a heating rate of 4–6 °C / min. The reduction reaction of the present invention is carried out at a pressure of 70–80 kPa.

[0009] To achieve both reduction and oxygen control while ensuring reaction safety, the mass ratio of the calcium pyrovanadate to metallic calcium in the reduction reaction is (1.46–1.59):1. To control the impurity content of metallic vanadium, the purity of the calcium pyrovanadate is ≥99.7%; more specifically, the impurity Fe in the calcium pyrovanadate is ≤0.04%, the impurity Si is ≤0.02%, and the total amount of impurities Ni, Cu, Nb, Mo, Co, Al, and Ag is ≤0.01%. The purity of the metallic calcium is ≥99.0%; more specifically, the total amount of impurities Ni, Cu, Nb, Mo, Co, Al, and Ag in the metallic calcium is ≤0.02%. To ensure uniform mixing and sufficient reaction, the particle size of the calcium pyrovanadate is ≤80 mesh; the particle size of the metallic calcium is 2 mm–4 mm.

[0010] This invention involves the reduction reaction of calcium pyrovanadate with metallic calcium under a protective gas atmosphere, wherein the protective gas is selected from one or more of nitrogen, helium, neon, or argon. Preferably, the purity of the protective gas is 99.99% or higher. In some embodiments of this invention, the protective gas is argon with a purity of 99.99%. This invention controls the pressure during the reduction reaction by controlling the pressure of the protective gas.

[0011] This invention involves reducing calcium pyrovanadate with metallic calcium, reacting the reaction product with water, and then sieving the resulting solid material by density screening followed by acid washing to obtain metallic vanadium. Specifically, the reaction product is reacted with water and stirred until no more bubbles are generated. The resulting material is then filtered and dried to obtain a solid material, which is then sieved by density screening. The vanadium powder obtained by density screening is then acid-washed and finally washed with water to obtain metallic vanadium. More specifically, the metallic vanadium obtained by this invention is vanadium powder.

[0012] The amount of water used in this invention is 1.5 to 2 times the amount of the reaction product. The pickling in this invention uses hydrochloric acid with a mass fraction concentration of 5% to 10%. In the pickling process of this invention, the amount of hydrochloric acid required per gram of metallic vanadium in the material obtained after density sieving is 0.2 mL to 0.4 mL, calculated as 37% hydrochloric acid. The pickling time in this invention is 20 to 30 minutes. The drying temperature in this invention is 60°C to 80°C.

[0013] The density screening described in this invention is specifically a vibrating density screening. In some embodiments of this invention, the density screening is performed using a vibrating density separation screen. This invention performs density screening on the obtained solid material before pickling, which effectively separates vanadium powder and some impurities, mainly calcium oxide, thus significantly reducing the amount of acid required for pickling, making it environmentally friendly.

[0014] This invention provides a method for preparing metallic vanadium. Specifically, the method is a highly efficient, temperature-controlled calcothermal reduction method for preparing metallic vanadium. It employs a calcothermal process, using calcium pyrovanadate instead of vanadium pentoxide to control the reaction heat. A specific mass ratio of calcium pyrovanadate is used to reduce metallic calcium, ensuring a stable and controllable reduction process. Other impurities in the product are removed by water washing, density sieving, and acid washing. Density sieving of the material before acid washing improves acid washing efficiency and saves a significant amount of acid. This method offers advantages such as a safe, controllable, easy-to-operate, and environmentally friendly process. Experiments show that the method described in this invention achieves stable and controllable reaction without the need for external coolant adjustment. The obtained metallic vanadium has the following content: V ≥ 99.0 wt%, Fe ≤ 0.08 wt%, Si ≤ 0.05 wt%, C ≤ 0.10 wt%, N ≤ 0.04 wt%, O ≤ 0.30 wt%, and the total impurities of Al, Ni, Cu, Nb, Mo, Co, and Ag ≤ 0.03 wt%. Detailed Implementation

[0015] This invention discloses a method for preparing metallic vanadium. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The method and application of this invention have been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the method and application described herein without departing from the content, spirit, and scope of this invention to implement and apply the technology of this invention.

[0016] The present invention will be further described below with reference to the embodiments:

[0017] Example 1

[0018] 150g of calcium pyrovanadate (purity 99.8%, with 0.04% Fe, 0.01% Si, and total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.01%, particle size ≤80 mesh) and 102g of metallic calcium (purity 99.2%, with total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.015%, particle size 2-3mm) were mixed evenly under argon purging and then placed into a graphite crucible in a vacuum furnace. The furnace was evacuated to 0.08 Pa and then purged twice with high-purity argon. Then, 99.99% high-purity argon was used as a protective gas, with a pressure of 70 kPa. The furnace temperature was increased to 600℃ at a rate of 8℃ / min, and then increased to 680℃ at a rate of 6℃ / min. The temperature was held for 40 minutes until the furnace reached the desired temperature. After cooling to room temperature, the furnace was dismantled, and the obtained product was placed in a quartz crucible. The quartz crucible was then placed in a cold water bath, and deionized water with a mass of 1.5 times the product mass was added to the quartz crucible. After the reaction stabilized, stirring was started, and stirring was stopped when no more bubbles were generated. The product was filtered, dried, and then the metallic vanadium powder was separated using a vibrating density separator. The obtained metallic vanadium powder was placed in a beaker, and 5% dilute hydrochloric acid was added to the beaker. After stirring for 25 minutes, the vanadium powder was washed clean with deionized water, filtered, and dried at 60°C to obtain metallic vanadium with a V content of 99.1 wt%, Fe content of 0.08 wt%, Si content of 0.04 wt%, C content of 0.09 wt%, N content of 0.04 wt%, O content of 0.25 wt%, and the total amount of impurities Al, Ni, Cu, Nb, Mo, Co, and Ag ≤0.03 wt%.

[0019] Example 2

[0020] 400g of calcium pyrovanadate (purity 99.7%, with 0.02% Fe, 0.02% Si, and total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.02%, particle size ≤120 mesh) and 260g of metallic calcium (purity 99.1%, with total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.018%, particle size 3-4mm) were mixed evenly under argon purging and then placed into a graphite crucible in a vacuum furnace. The furnace was evacuated to 0.09 Pa and then purged three times with high-purity argon. Then, 99.99% high-purity argon was used as a protective gas, with a pressure of 75 kPa. The furnace temperature was increased to 600℃ at a rate of 9℃ / min, and then increased to 690℃ at a rate of 4℃ / min, and held for 50 minutes. After cooling to room temperature, the furnace was dismantled, and the obtained product was placed in a quartz crucible. The quartz crucible was then placed in a cold water bath, and deionized water with a mass of 1.8 times the product mass was added to the quartz crucible. After the reaction stabilized, stirring was started, and stirring was stopped when no more bubbles were generated. The product was filtered, dried, and then the metallic vanadium powder was separated using a vibrating density separator. The obtained metallic vanadium powder was placed in a beaker, and 7% dilute hydrochloric acid was added to the beaker. After stirring for 20 minutes, the vanadium powder was washed clean with deionized water, filtered, and dried at 80°C to obtain metallic vanadium with a V content of 99.2 wt%, Fe of 0.07 wt%, Si of 0.03 wt%, C of 0.08 wt%, N of 0.03 wt%, O of 0.26 wt%, and a total impurity content of Al, Ni, Cu, Nb, Mo, Co, and Ag ≤0.02 wt%.

[0021] Example 3

[0022] 600g of calcium pyrovanadate (purity 99.8%, with 0.03% Fe, 0.01% Si, and total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.02%, particle size ≤80 mesh) and 378g of metallic calcium (purity 99.0%, with total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.012%, particle size 2-3mm) were mixed evenly under argon purging and then placed into a graphite crucible in a vacuum furnace. The furnace was evacuated to 0.07 Pa and then purged twice with high-purity argon. Then, 99.99% high-purity argon was used as a protective gas, with a pressure of 80 kPa. The furnace temperature was increased to 600℃ at a rate of 10℃ / min, and then increased to 700℃ at a rate of 5℃ / min. The temperature was held for 60 minutes. After the temperature drops to room temperature, the furnace is dismantled, and the obtained product is placed in a quartz crucible. The quartz crucible is then placed in a cold water bath, and deionized water with a mass twice that of the product is added to the quartz crucible. Once the reaction stabilizes, stirring is started, and stirring is stopped when no more bubbles are generated. The product is then filtered, dried, and the metallic vanadium powder is separated using a vibrating density separator. The obtained metallic vanadium powder is placed in a beaker, and 10% dilute hydrochloric acid is added to the beaker. After stirring for 30 minutes, the vanadium powder is washed clean with deionized water, filtered, and dried at 70°C to obtain metallic vanadium with a V content of 99.0 wt%, Fe content of 0.02 wt%, Si content of 0.02 wt%, C content of 0.10 wt%, N content of 0.04 wt%, O content of 0.27 wt%, and the total amount of impurities Al, Ni, Cu, Nb, Mo, Co, and Ag ≤0.02 wt%.

[0023] Comparative Example 1

[0024] 178.43g of V₂O₅ (purity 99.91%, containing 0.02% Fe, 0.01% Si, and total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.02%, particle size ≤80 mesh), 210.67g of metallic calcium (purity 99.0%, containing total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.011%, particle size 2–3 mm), and 256.67g of CaCl₂ (purity 99.5%, and its...) were mixed together. The mixture (containing 0.015% Fe, 0.014% Si, and total impurities of Ni, Cu, Nb, Mo, Co, Al, and Ag ≤0.02%, particle size ≤80 mesh) was thoroughly mixed with argon and then placed into a graphite crucible in a vacuum furnace. After evacuating to 0.1 Pa, the furnace was cleaned twice with high-purity argon gas. Then, 99.99% high-purity argon gas was used as a protective gas, with a pressure of 70 kPa. The furnace temperature was increased to 600℃ at a rate of 10℃ / min and held for 60 min. Finally, the furnace temperature was increased by 5... The furnace temperature was raised to 680℃ at a heating rate of ℃ / min and held for 40 minutes. After the furnace temperature cooled to room temperature, the furnace was dismantled, and the obtained product was placed in a quartz crucible. The quartz crucible was then placed in a cold water bath, and deionized water was added to the quartz crucible. After the reaction stabilized, stirring was started, and stirring was stopped when no more bubbles were generated. After filtration, 10% dilute hydrochloric acid was added to a beaker and stirred. The pH value of the solution was monitored using a pH meter until the pH value of the solution stabilized between 2 and 3 (the solution was filtered after filling the quartz crucible and the liquid was poured out). After being placed in the waste liquid tank, acid was added and stirred continuously (850 mL of acid was consumed in the process, based on a commercially available HCl concentration of 37%). The vanadium powder was washed clean with deionized water, filtered, and dried at 60°C to obtain metallic vanadium powder with a V content of 99.0 wt%, Fe of 0.021 wt%, Si of 0.019 wt%, C of 0.09 wt%, N of 0.04 wt%, O of 0.35 wt%, and a total impurity content of Al, Ni, Cu, Nb, Mo, Co, and Ag ≤0.02 wt%.

[0025] To further illustrate the technical advantages of this patent, a comparison was made with the traditional calcothermal method for preparing metallic vanadium powder using high-purity vanadium pentoxide as raw material. The results are shown in Table 1.

[0026] Table 1

[0027]

[0028]

[0029] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing metallic vanadium, characterized by, Includes the following steps: S1) Under a protective gas atmosphere, calcium pyrovanadate with metallic calcium in a mass ratio of (1.46 to 1.59):1 undergoes a reduction reaction. S2) React the reaction product obtained in step S1) with water, then perform density sieving on the resulting solid material, and then acid wash to obtain metallic vanadium.

2. The production method according to claim 1, characterized by, In step S1), the purity of the calcium pyrovanadate is ≥99.7%; The calcium pyrovanadate contains impurities of Fe ≤ 0.04%, Si ≤ 0.02%, and the total amount of impurities Ni, Cu, Nb, Mo, Co, Al, and Ag ≤ 0.01%.

3. The preparation method according to claim 1, characterized in that, In step S1), the purity of the metallic calcium is ≥99.0%; The total amount of impurities Ni, Cu, Nb, Mo, Co, Al, and Ag in the metallic calcium is ≤0.02%.

4. The preparation method according to claim 1, characterized in that, In step S1), the particle size of the calcium pyrovanadate is ≤80 mesh; The particle size of the metallic calcium is 2 mm to 4 mm.

5. The preparation method according to claim 1, characterized in that, In step S1), the temperature of the reduction reaction is 680℃~700℃, and the time of the reduction reaction is 40min~60min.

6. The preparation method according to claim 5, characterized in that, In step S1), the reduction reaction specifically involves: first heating to a first temperature at a heating rate of 8℃ / min to 10℃ / min, and then heating to the temperature of the reduction reaction at a heating rate of 4℃ / min to 6℃ / min; the first temperature is less than 600℃.

7. The preparation method according to claim 1, characterized in that, In step S1), the reduction reaction is carried out at a pressure of 70 kPa to 80 kPa.

8. The preparation method according to claim 1, characterized in that, In step S2), the amount of water used is 1.5 to 2 times that of the reaction product.

9. The preparation method according to claim 1, characterized in that, In step S2), the pickling is carried out using hydrochloric acid with a mass fraction concentration of 5% to 10%; In the pickling process, the amount of hydrochloric acid required per gram of metallic vanadium in the material obtained after density sieving is 0.2 mL to 0.4 mL, calculated as hydrochloric acid with a mass fraction concentration of 37%.

10. The preparation method according to claim 1, characterized in that, In step S2), the pickling time is 20 min to 30 min.

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