Preparation method of particle vanadium pentoxide

Abstract

A preparation method of granular vanadium pentoxide comprises the following steps: (1) adding ammonium metavanadate into a mixed solvent, heating, stirring and dissolving to obtain a solution A; (2) adding ammonia water and sodium acetate into the solution A, removing impurities, and carrying out solid-liquid separation to obtain a vanadium-containing purified solution; (3) heating the vanadium-containing purified solution, carrying out gradient vanadium precipitation, and carrying out solid-liquid separation to obtain a vanadium precipitation mother solution and solid-phase ammonium polyvanadate; and (4) calcining the ammonium polyvanadate for deamination to obtain particle vanadium pentoxide. According to the invention, a mixed solvent of water, ethylene glycol and acetone is adopted to prepare vanadium pentoxide with uniform particle size and large particle size; sodium acetate is added in the impurity removal process, the molecular structure of the sodium acetate contains hydrophobic carbon chains, the sodium acetate is alkalescent in an aqueous solution, and granular vanadium pentoxide can be generated through catalysis; product particle size distribution is uniform; the vanadium pentoxide product with the purity larger than or equal to 99.99 wt% and the particle size larger than or equal to 150 micrometers is prepared, the particle size within the range of 180 micrometers to 200 micrometers is larger than or equal to 80%, and particle size distribution is uniform.

Description

Technical Field

[0001] This invention belongs to the field of vanadium chemical metallurgy technology, specifically relating to a method for preparing granular vanadium pentoxide. Background Technology

[0002] The traditional method for producing vanadium pentoxide is the sodium roasting of vanadium slag followed by ammonium salt precipitation, with over 65% of the vanadium product coming from this method. There are two types of ammonium salt precipitation: one involves adjusting the pH of a solution containing pentavalent vanadium to 8.5–9.5, then adding ammonium salt at a V₂O₅ to ammonium salt mass ratio of 1:1.3–1.5 to precipitate ammonium metavanadate; the other involves adjusting the pH of the solution stepwise to 1.5–2.5, adding ammonium salt to precipitate ammonium polyvanadate, and then calcining the resulting ammonium metavanadate or ammonium polyvanadate to obtain vanadium pentoxide. However, the vanadium pentoxide obtained using these processes has a high impurity content, with a vanadium pentoxide grade generally only around 98%, containing impurities such as Fe, Al, K, Na, Ca, Mg, Si, P, S, and As, making it difficult to meet the purity requirements of vanadium pentoxide in various fields.

[0003] In addition to purity requirements, some customers require vanadium pentoxide products with larger particle sizes and specific particle size ranges for their applications. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing vanadium pentoxide particles, which yields vanadium pentoxide with high purity, large particles, and relatively uniform particle size.

[0005] The technical solution adopted by this invention to solve its technical problem is a method for preparing granular vanadium pentoxide, comprising the following steps: (1) Add ammonium metavanadate to the mixed solvent, heat and stir continuously until dissolved to obtain solution A.

[0006] (2) Add ammonia and sodium acetate to solution A obtained in step (1) to adjust the pH of the solution to 7.0-8.0 for impurity removal, solid-liquid separation, and obtain vanadium-containing purified solution; Studies have shown that sodium acetate contains hydrophobic carbon chains in its molecular structure, exhibits weak alkalinity in aqueous solution, and can catalyze the formation of particulate vanadium pentoxide; the product has a uniform particle size distribution. Furthermore, sodium acetate can be removed by water dissolution.

[0007] (3) Heat the vanadium-containing purified liquid obtained in step (2), and then adjust the pH to two stages of gradient precipitation of vanadium, namely 4-6 and 2-3. After the precipitation of vanadium is completed, the solid and liquid are separated to obtain the vanadium-precipitated mother liquor and solid ammonium polyvanadate.

[0008] (4) The ammonium polyvanadate obtained in step (3) is calcined to remove ammonia, and granular vanadium pentoxide is obtained.

[0009] Furthermore, in step (1), the mixed solvent is a mixture of water, ethylene glycol, and acetone.

[0010] Furthermore, in step (1), the volume ratio of water, ethylene glycol, and acetone is 1:0.1–0.2:0.01–0.05. Studies have shown that ethylene glycol and acetone are reactive, and the aforementioned mixing ratio is more conducive to preparing vanadium pentoxide with uniform particle size and large particle size during the reaction process. Moreover, both ethylene glycol and acetone can be removed by water dissolution.

[0011] Furthermore, in step (1), the heating temperature is above 30°C, preferably 50-60°C.

[0012] Furthermore, in step (2), the molar ratio of sodium acetate added to ammonia molecules in ammonia water is 1:2 to 5.

[0013] Furthermore, in step (3), the vanadium-containing purification solution is heated to a temperature of 60–80°C.

[0014] Furthermore, in step (3), the vanadium precipitation time is 5 to 30 minutes when the pH is 4 to 6, and 20 to 60 minutes when the pH is 2 to 3.

[0015] Furthermore, in step (3), the obtained solid ammonium polyvanadate is washed with water to remove water-soluble impurities.

[0016] Furthermore, in step (3), sulfuric acid is used to adjust the pH.

[0017] Furthermore, in step (4), the calcination temperature is 400-500℃ and the time is 1-3 hours.

[0018] Compared with existing technical solutions, the present invention has at least the following beneficial effects: (1) The present invention uses a mixed solvent of water, ethylene glycol and acetone. Ethylene glycol and acetone are active. Under the above mixing ratio, it is more conducive to preparing vanadium pentoxide with uniform particle size and large particle size during the reaction process. (2) In the process of removing impurities, sodium acetate is added. Sodium acetate contains hydrophobic carbon chains in its molecular structure and is weakly alkaline in aqueous solution. It can catalyze the generation of granular vanadium pentoxide. The product has a uniform particle size distribution. (3) The present invention utilizes the vanadium dissolution and gradient precipitation method to prepare vanadium pentoxide products with a purity ≥99.99wt% and a particle size ≥150μm. It can also achieve precise control of the particle size of vanadium pentoxide, so that the particles in the range of 180μm~200μm are ≥80%, and the particle size distribution is uniform, which meets the specific needs of customers. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments. Example 1

[0020] The preparation method of granular vanadium pentoxide in this embodiment includes the following steps: (1) Add ammonium metavanadate to the mixed solvent, heat and stir continuously until dissolved to obtain solution A; In step (1), the mixed solvent is a mixture of water, ethylene glycol, and acetone. The volume ratio of water, ethylene glycol, and acetone is 1:0.1:0.05.

[0021] In step (1), the heating temperature is 50°C.

[0022] (2) Add ammonia and sodium acetate to solution A obtained in step (1) to adjust the pH of the solution to 7.0 for impurity removal, and perform solid-liquid separation to obtain vanadium-containing purified solution; In step (2), the molar ratio of sodium acetate added to ammonia molecules in ammonia water is 1:2.

[0023] (3) Heat the vanadium-containing purified liquid obtained in step (2), and then adjust the pH to 5.0 and 2.0 in two stages to carry out gradient precipitation of vanadium. After the precipitation of vanadium is completed, the solid and liquid are separated to obtain the vanadium precipitation mother liquor and solid ammonium polyvanadate. In step (3), the vanadium-containing purification solution is heated to a temperature of 60°C.

[0024] In step (3), the vanadium precipitation time is 10 minutes at pH 5.0 and 30 minutes at pH 2.0.

[0025] In step (3), the obtained solid ammonium polyvanadate is washed with water to remove water-soluble impurities.

[0026] In step (3), sulfuric acid is used to adjust the pH.

[0027] (4) The ammonium polyvanadate obtained in step (3) is calcined to remove ammonia, and granular vanadium pentoxide is obtained.

[0028] In step (4), the calcination temperature is 400℃ and the time is 2 hours.

[0029] The vanadium pentoxide obtained in this embodiment has a purity of 99.992 wt%, a particle size of ≥150 μm, and ≥80% of the particles are in the range of 180 μm to 200 μm, with a uniform particle size distribution. Example 2

[0030] The preparation method of granular vanadium pentoxide in this embodiment includes the following steps: (1) Add ammonium metavanadate to the mixed solvent, heat and stir continuously until dissolved to obtain solution A; In step (1), the mixed solvent is a mixture of water, ethylene glycol, and acetone. The volume ratio of water, ethylene glycol, and acetone is 1:0.2:0.05.

[0031] In step (1), the heating temperature is 50°C.

[0032] (2) Add ammonia and sodium acetate to solution A obtained in step (1) to adjust the pH of the solution to 8.0 for impurity removal, and perform solid-liquid separation to obtain vanadium-containing purified solution; In step (2), the molar ratio of sodium acetate added to ammonia molecules in ammonia water is 1:5.

[0033] (3) Heat the vanadium-containing purified liquid obtained in step (2), and then adjust the pH to 4.0 and 2.5 in two stages to carry out gradient precipitation of vanadium. After the precipitation of vanadium is completed, the solid and liquid are separated to obtain the vanadium precipitation mother liquor and solid ammonium polyvanadate. In step (3), the vanadium-containing purification solution is heated to 80°C.

[0034] In step (3), the vanadium precipitation time is 5 minutes at pH 4.0 and 40 minutes at pH 2.5.

[0035] In step (3), the obtained solid ammonium polyvanadate is washed with water to remove water-soluble impurities.

[0036] In step (3), sulfuric acid is used to adjust the pH.

[0037] (6) Calcining the ammonium polyvanadate obtained in step (3) to remove ammonia, yielding granular vanadium pentoxide.

[0038] In step (4), the calcination temperature is 500℃ and the time is 1 hour.

[0039] The vanadium pentoxide obtained in this embodiment has a purity of 99.991 wt%, a particle size of ≥150 μm, and ≥80% of the particles are in the range of 180 μm to 200 μm, with a uniform particle size distribution. Example 3

[0040] The preparation method of granular vanadium pentoxide in this embodiment includes the following steps: (1) Add ammonium metavanadate to the mixed solvent, heat and stir continuously until dissolved to obtain solution A; In step (1), the mixed solvent is a mixture of water, ethylene glycol, and acetone. The volume ratio of water, ethylene glycol, and acetone is 1:0.2:0.01.

[0041] In step (1), the heating temperature is 55°C.

[0042] (2) Add ammonia and sodium acetate to solution A obtained in step (1) to adjust the pH of the solution to 8.0 for impurity removal, and perform solid-liquid separation to obtain vanadium-containing purified solution; In step (2), the molar ratio of sodium acetate added to ammonia molecules in ammonia water is 1:3.

[0043] (3) Heat the vanadium-containing purified liquid obtained in step (2), and then adjust the pH to 6.0 and 3.0 in two stages to carry out gradient precipitation of vanadium. After the precipitation of vanadium is completed, the solid and liquid are separated to obtain the vanadium precipitation mother liquor and solid ammonium polyvanadate. In step (3), the vanadium-containing purification solution is heated to a temperature of 70°C.

[0044] In step (3), the vanadium precipitation time is 20 minutes at pH 6.0 and 20 minutes at pH 3.0.

[0045] In step (3), the obtained solid ammonium polyvanadate is washed with water to remove water-soluble impurities.

[0046] In step (3), sulfuric acid is used to adjust the pH.

[0047] (7) The ammonium polyvanadate obtained in step (3) is calcined to remove ammonia, and granular vanadium pentoxide is obtained.

[0048] In step (4), the calcination temperature is 450℃ and the time is 2 hours.

[0049] The vanadium pentoxide obtained in this embodiment has a purity of 99.991 wt%, a particle size of ≥150 μm, and ≥80% of the particles are in the range of 180 μm to 200 μm, with a uniform particle size distribution.

[0050] Comparative Example 1 In this comparative example, ethylene glycol is not added in step (1), and other operations and parameters are the same as in Example 1.

[0051] The vanadium pentoxide obtained in this comparative example had a purity of 99.542 wt% and a particle size ≥20 μm, with ≥10% of particles in the 180 μm to 200 μm range, indicating uneven particle size distribution. This demonstrates that the absence of ethylene glycol affects the purity and particle size of the final vanadium pentoxide product.

[0052] Comparative Example 2 In this comparative example, acetone is not added in step (1), and other operations and parameters are the same as in Example 1.

[0053] The vanadium pentoxide obtained in this comparative example had a purity of 99.413 wt% and a particle size ≥10 μm, with ≥12% of particles in the 180 μm to 200 μm range, indicating uneven particle size distribution. This demonstrates that the absence of acetone affects the purity and particle size of the final vanadium pentoxide product.

[0054] Comparative Example 3 Sodium acetate is not added in step (2) of this comparative example. Other operations and parameters are the same as in Example 1.

[0055] The vanadium pentoxide obtained in this comparative example had a purity of 99.982 wt% and a particle size ≥ 2 μm, with ≥ 2% of particles in the 180 μm to 200 μm range, indicating an uneven particle size distribution. This demonstrates that the absence of sodium acetate affects the purity and particle size of the final vanadium pentoxide product.

Claims

1. A method for preparing granular vanadium pentoxide, characterized in that, Includes the following steps: (1) Add ammonium metavanadate to the mixed solvent, heat and stir continuously until dissolved to obtain solution A; (2) Add ammonia and sodium acetate to solution A obtained in step (1) to adjust the pH of the solution to 7.0-8.0 for impurity removal, solid-liquid separation, and obtain vanadium-containing purified solution; (3) Heat the vanadium-containing purified liquid obtained in step (2), and then adjust the pH to two stages of 4-6 and 2-3 to carry out gradient precipitation of vanadium. After the precipitation of vanadium is completed, the solid and liquid are separated to obtain the vanadium precipitation mother liquor and solid ammonium polyvanadate. (4) The ammonium polyvanadate obtained in step (3) is calcined to remove ammonia, and granular vanadium pentoxide is obtained.

2. The method for preparing granular vanadium pentoxide according to claim 1, characterized in that, In step (1), the mixed solvent is a mixture of water, ethylene glycol and acetone.

3. The method for preparing granular vanadium pentoxide according to claim 2, characterized in that, In step (1), the volume ratio of water, ethylene glycol and acetone is 1:0.1~0.2:0.01~0.

05.

4. The method for preparing particulate vanadium pentoxide according to claim 1 or 2, characterized in that, In step (1), the heating temperature is above 30°C.

5. The method for preparing granular vanadium pentoxide according to claim 4, characterized in that, In step (1), the heating temperature is 50-60℃.

6. The method for preparing particulate vanadium pentoxide according to claim 1 or 2, characterized in that, In step (2), the molar ratio of sodium acetate added to ammonia molecules in ammonia water is 1:2 to 5.

7. The method for preparing particulate vanadium pentoxide according to claim 1 or 2, characterized in that, In step (3), the vanadium-containing purification solution is heated to a temperature of 60–80°C.

8. The method for preparing particulate vanadium pentoxide according to claim 1 or 2, characterized in that, In step (3), the vanadium precipitation time is 5 to 30 minutes when the pH is 4 to 6; and / or, the vanadium precipitation time is 20 to 60 minutes when the pH is 2 to 3.

9. The method for preparing particulate vanadium pentoxide according to claim 1 or 2, characterized in that, In step (3), the obtained solid ammonium polyvanadate is washed with water to remove water-soluble impurities; and / or, in step (3), sulfuric acid is used to adjust the pH.

10. The method for preparing particulate vanadium pentoxide according to claim 1 or 2, characterized in that, In step (4), the calcination temperature is 400-500℃ and the time is 1-3 hours.