Preparation method of vanadium dichloride material

Abstract

The invention discloses a preparation method of a vanadium dichloride material, and belongs to the field of chemical engineering. The method comprises the following steps: a, putting crude metal vanadium powder into an atmosphere furnace, introducing argon for emptying, introducing hydrogen chloride gas, and heating for chlorination reaction; b, after the reaction is completed, cooling to a certain temperature, introducing argon, continuously cooling to room temperature, then taking out a reaction product, and grinding in an argon atmosphere; c, putting the reaction product into the atmosphere furnace, and repeating the operation of the steps a and b to obtain a secondary chlorination product; d, putting the secondary chlorination product into an organic solvent, carrying out ultrasonic dispersion, filtering and separating to obtain a vanadium dichloride-organic solvent solution; and e, distilling the solution under the protection of argon to obtain a supersaturated solution, filtering, and drying in vacuum to obtain the vanadium dichloride material. The method disclosed by the invention is simple in process, convenient in condition control and relatively low in production cost, and a vanadium dichloride product with relatively high purity can be obtained.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and particularly relates to a method for preparing a vanadium dichloride material. Background Art

[0002] Vanadium dichloride can be used as a catalyst and reducing agent in the chemical industry. It is also an intermediate for preparing a variety of medicines, vanadium-containing compounds and synthetic organic compounds. In addition, vanadium dichloride is also an important intermediate compound for preparing high-purity metallic vanadium. The quality of vanadium dichloride has an important influence on the purity of metallic vanadium. At present, the purity specifications of vanadium dichloride products available on the market are mostly around 85%. The preparation of high-purity metallic vanadium urgently requires vanadium dichloride raw materials with higher purity. Therefore, it is of great significance to develop a method for preparing vanadium dichloride with high sample purity and simple process.

[0003] At present, there are two main methods for preparing vanadium dichloride. The first is to reduce vanadium trichloride with hydrogen at 430℃: 2VCl3+H2=2VCl2+2HCl; the other method is to decompose vanadium trichloride in a nitrogen flow at 800℃: 2VCl3=VCl2+VCl4. The above preparation methods either involve the use of hydrogen, which has the risk of explosion and makes process control difficult; or the raw material VCl3 is difficult to obtain and the production cost is high. Summary of the invention

[0004] In view of the problems existing in the existing vanadium dichloride preparation method, the present invention provides a preparation method for vanadium dichloride, which uses crude metal vanadium powder as a raw material, hydrogen chloride as a chlorination medium, and then separates and purifies it through an organic solvent. The method has a simple preparation process, convenient condition control, and can obtain a vanadium dichloride product with higher purity.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing vanadium dichloride material, comprising the following steps:

[0006] a. Place crude vanadium metal powder into an atmosphere furnace, evacuate with argon gas, then introduce hydrogen chloride gas, and heat to carry out chlorination reaction;

[0007] b. After the reaction is completed, cool to a certain temperature, introduce argon and continue to cool to room temperature, then take out the reaction product and grind it under argon atmosphere;

[0008] c. The reaction product obtained in step b is placed in an atmosphere furnace, and steps a and b are repeated to obtain a secondary chlorination product;

[0009] d. placing the secondary chlorination product in an organic solvent, dispersing it ultrasonically, and separating it by filtration to obtain a vanadium dichloride-organic solvent solution;

[0010] e. distilling the solution obtained in step d under argon protection to obtain a supersaturated solution, filtering it, and vacuum drying it to obtain a vanadium dichloride material.

[0011] In the above step a, the purity of the crude vanadium metal powder is ≥96.0%, the impurity contents of C, O and N are not higher than 0.4%, 0.4% and 0.05% respectively, the content of other impurities is not higher than 0.5%, and the powder particle size is ≤50 mesh.

[0012] In the above step a, the atmosphere furnace is a vertical atmosphere furnace; the argon gas is introduced and evacuated for more than 30 minutes.

[0013] In the above step a, the purity of hydrogen chloride is ≥99.9%.

[0014] In the above step a, the chlorination reaction temperature is 830-900° C., and the reaction time is 2-4 h.

[0015] In the above step b, the reaction is cooled to 400-500°C after completion.

[0016] In the above step d, the organic solvent is any one of ethanol and ether.

[0017] In the above step e, the distillation temperature is 78-85°C.

[0018] In the above step e, the vacuum drying temperature is 80-90° C. and the drying time is 4-10 hours.

[0019] In the above steps a, b and e, the purity of the argon gas is ≥99.99%.

[0020] The invention has the following beneficial effects: the invention uses crude metal vanadium powder as a raw material and hydrogen chloride as a chlorination medium; since the chlorinating property of hydrogen chloride is relatively weak, vanadium in the raw material can be converted into vanadium dichloride in a low vanadium valence state, and the chemical reaction formula is as follows: V+2HCl=VCl2+H2; the reaction is a gas-solid reaction with a relatively fast reaction speed; solid vanadium dichloride can be obtained by controlling the reaction temperature, thereby avoiding the problem that the temperature is too high and the vanadium dichloride is difficult to collect after gasification; after primary chlorination, the sample is ground and then secondary chlorinated, thereby improving the chlorination efficiency (experimental results show that the primary chlorination rate (in terms of vanadium dichloride) is about 60%, and the secondary rechlorination rate after grinding reaches about 80%); the vanadium dichloride is dissolved by an organic solvent, thereby achieving the purpose of separating residual metal and vanadium dichloride, and then distillation separation is performed to obtain vanadium dichloride with a relatively high purity (≥99%).

[0021] The invention does not involve the use of explosive hydrogen and difficult-to-prepare vanadium trichloride raw materials, and has simple preparation process, convenient condition control, low production cost, and certain industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the XRD pattern of the vanadium dichloride product obtained in Example 1. DETAILED DESCRIPTION

[0023] The technical solution of the present invention can be specifically implemented in the following manner.

[0024] Take an appropriate amount of crude metallic vanadium powder and put it into an atmosphere furnace, introduce argon gas to exhaust the air; introduce hydrogen chloride gas instead, raise the temperature to 830-900°C, and keep it warm for 2-4 hours; after the insulation is completed, cool it to 400-500°C and introduce argon gas instead, continue to cool it to room temperature, take it out and grind it in an argon atmosphere; repeat the above chlorination steps once; put the obtained sample into an organic solvent, ultrasonically disperse it, filter and separate it to obtain a vanadium dichloride-organic solvent solution; distill the above solution to obtain a supersaturated solution, filter it, and vacuum dry it to obtain a vanadium dichloride product.

[0025] It is further explained that in order to ensure effective contact between the gas and the vanadium powder, the time for introducing argon and venting should be greater than 30 minutes.

[0026] Further explanation: the present invention limits the chlorination reaction temperature to 830-900°C, which is a more suitable chlorination temperature range. Below 830°C, the chlorination efficiency is low, while above 900°C, the volatility of vanadium dichloride is high and the loss is large.

[0027] The technical solution and effects of the present invention are further illustrated below through practical examples.

[0028] Example

[0029] Example 1

[0030] Take an appropriate amount of crude metallic vanadium powder (purity of 98.5%, average particle size of 50 mesh) and put it into a vertical atmosphere furnace, and introduce argon gas to evacuate for 60 minutes; introduce hydrogen chloride gas instead, heat to 850°C, and keep warm for 2 hours; after the insulation is completed, cool to 400°C and introduce argon gas instead, continue to cool to room temperature, take out and grind in argon atmosphere; repeat the above chlorination step once to obtain a sample with a vanadium dichloride content of 79.8% (obtained by analyzing the chloride ion content of the sample); put the obtained sample into ethanol, ultrasonically disperse for 30 minutes, filter, and obtain a vanadium dichloride-ethanol solution; distill the above solution at 80°C under argon protection to obtain a supersaturated solution, filter, and vacuum dry at 85°C for 5 hours to obtain a vanadium dichloride product with a purity of 99.1%.

[0031] The product was analyzed by XRD, and the results were as follows: Figure 1 As shown: the diffraction peak corresponds to the VCl2 standard peak, and there is no obvious impurity phase peak.

[0032] Example 2

[0033] Take an appropriate amount of crude metallic vanadium powder (purity of 98.5%, average particle size of 100 mesh) and put it into an atmosphere furnace, and introduce argon gas to evacuate for 40 minutes; introduce hydrogen chloride gas instead, heat to 830°C, and keep warm for 3 hours; after the insulation is completed, cool to 400°C and introduce argon gas instead, continue to cool to room temperature, take out and grind in an argon atmosphere; repeat the above chlorination steps once, and the sample has a vanadium dichloride content of 81.7%; put the obtained sample into ethanol, ultrasonically disperse for 30 minutes, filter and separate to obtain a vanadium dichloride-ethanol solution; distill the above solution at 80°C under argon protection to obtain a supersaturated solution, filter, and vacuum dry at 85°C for 5 hours to obtain a vanadium dichloride product with a purity of 99.3%.

[0034] Example 3

[0035] Take an appropriate amount of crude metallic vanadium powder (purity of 96.5%, average particle size of 50 mesh) and put it into an atmosphere furnace, and introduce argon gas to evacuate for 40 minutes; introduce hydrogen chloride gas instead, heat to 900°C, and keep warm for 2 hours; after the insulation is completed, cool to 400°C and introduce argon gas instead, continue to cool to room temperature, take out and grind in argon atmosphere; repeat the above chlorination steps once, and the sample vanadium dichloride content is 79.6%; put the obtained sample into ethanol, ultrasonically disperse for 30 minutes, filter and separate to obtain vanadium dichloride-ethanol solution; distill the above solution at 80°C under argon protection to obtain a supersaturated solution, filter, and vacuum dry at 85°C for 5 hours to obtain a vanadium dichloride product with a purity of 99.2%.

Claims

1. A method for preparing a vanadium dichloride material, characterized in that: The steps include: a. Place crude vanadium metal powder into an atmosphere furnace, evacuate with argon gas, then introduce hydrogen chloride gas, and heat to carry out chlorination reaction; b. After the reaction is completed, cool to a certain temperature, introduce argon and continue to cool to room temperature, then take out the reaction product and grind it under argon atmosphere; c. The reaction product obtained in step b is placed in an atmosphere furnace, and steps a and b are repeated to obtain a secondary chlorination product; d. placing the secondary chlorination product in an organic solvent, dispersing it ultrasonically, and separating it by filtration to obtain a vanadium dichloride-organic solvent solution; e. distilling the solution obtained in step d under argon protection to obtain a supersaturated solution, filtering it, and vacuum drying it to obtain a vanadium dichloride material.

2. The method for preparing vanadium dichloride material according to claim 1, characterized in that: In step a, the purity of the crude metallic vanadium powder is ≥96.0%, the impurity contents of C, O and N are not higher than 0.4%, 0.4% and 0.05% respectively, the content of other impurities is not higher than 0.5%, and the powder particle size is ≤50 mesh.

3. The method for preparing vanadium dichloride material according to claim 1, characterized in that: In step a, the atmosphere furnace is a vertical atmosphere furnace; the argon gas is introduced and evacuated for more than 30 minutes.

4. The method for preparing vanadium dichloride material according to claim 1, characterized in that: In step a, the purity of hydrogen chloride is ≥99.9%.

5. The method for preparing vanadium dichloride material according to claim 1, characterized in that: In step a, the chlorination reaction temperature is 830-900° C., and the reaction time is 2-4 hours.

6. The method for preparing the vanadium dichloride material according to claim 1, characterized in that: In step b, the reaction is cooled to 400-500° C. after completion.

7. The method for preparing the vanadium dichloride material according to claim 1, characterized in that: In step d, the organic solvent is any one of ethanol and ether.

8. The method for preparing the vanadium dichloride material according to claim 1, characterized in that: In step e, the distillation temperature is 78-85°C.

9. The method for preparing vanadium dichloride material according to claim 1, characterized in that: In step e, the vacuum drying temperature is 80-90° C. and the drying time is 4-10 hours.

10. The method for preparing the vanadium dichloride material according to claim 1, characterized in that: In steps a, b and e, the purity of the argon gas is ≥99.99%.

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