Preparation method of high-purity vanadyl oxalate and product thereof

Abstract

The invention provides a preparation method of high-purity vanadyl oxalate and a product thereof. According to the preparation method of the high-purity vanadyl oxalate provided by the invention, the high-purity vanadyl oxalate is prepared in one step by adopting a mechanochemical method. The preparation method specifically comprises the step of grinding vanadium pentoxide and oxalic acid at a high rotating speed, such as 500-5000 r / min. Therefore, the preparation method provided by the invention is rapid in process, simple in procedure, mild in condition and strong in expansibility, not only can obtain the high-purity vanadyl oxalate solid product, but also can obtain the high-purity vanadyl oxalate solution product through simple mixing of the subsequent high-purity vanadyl oxalate solid product and water, and is suitable for large-scale production. Compared with the prior art in which oxalic acid and vanadium pentoxide are used for water-phase reaction, the method has the advantage that complicated post-treatment steps such as filtration, concentration, crystallization and drying are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical products, and specifically relates to a preparation method of high-purity vanadyl oxalate and a product thereof. Background Art

[0002] Vanadium is known as the "MSG of modern industry" and is an important raw material that is indispensable for the development of modern industry, national defense and science and technology. At present, vanadium-based compounds have key uses in many fields such as metallurgy, catalysts, electronics, new energy and new materials. Among them, vanadium oxalate (or vanadium oxalate) as a soluble low-priced organic vanadium compound is not only a basic chemical raw material, but also an intermediate raw material for the preparation of high-performance vanadium products including vanadium dioxide.

[0003] At present, the common vanadium oxalate on the market is sold in the form of aqueous solution, and there are few solid products and the price is high, especially high-purity solid products and solution products are not easy to obtain. In recent years, the publicly reported preparation method of vanadium oxalate generally uses oxalic acid and vanadium pentoxide to react in liquid phase to generate vanadium oxalate aqueous solution, and then filters the solid particles and adds water to adjust the concentration to obtain the vanadium oxalate solution product. For solid vanadium oxalate products, subsequent heating and concentration, cooling and crystallization, separation and drying processes must be carried out. However, the heating and concentration process has high energy consumption and takes a long time, and high-concentration vanadium oxalate is easily hydrolyzed, decomposed or carbonized, which can easily affect the product quality.

[0004] Therefore, developing a simple, efficient and mild method for preparing high-purity vanadium oxalate and its aqueous solution product is still a difficult problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a preparation method of high-purity vanadyl oxalate and its product. The preparation method has rapid process, simple procedure, mild conditions, strong scalability, and is suitable for large-scale production.

[0006] To achieve this object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for preparing high-purity vanadyl oxalate, comprising the following steps: Vanadium pentoxide and oxalic acid are ground at 500-5000 r / min, and high-purity vanadyl oxalate is obtained after the two react. High-speed grinding overcomes the energy barrier of solid-phase reaction and promotes the reaction.

[0007] Preferably, the grinding rate is 1000-3000 r / min.

[0008] Preferably, the mass ratio of vanadium pentoxide to oxalic acid is 1:1.8 to 1:2.5.

[0009] More preferably, the mass ratio of the vanadium pentoxide to oxalic acid is 1:1.9 to 1:2.2.

[0010] Preferably, the purity of the vanadium pentoxide is ≥99.5%.

[0011] Preferably, the grinding time is 1 to 6 h.

[0012] More preferably, the grinding time is 2 to 4 h.

[0013] Preferably, a drying step is further included after the grinding.

[0014] Preferably, the drying temperature is 60-100° C. and the drying time is 1-24 h.

[0015] Preferably, after obtaining the high-purity vanadyl oxalate, the high-purity vanadyl oxalate is mixed with water to obtain a high-purity vanadyl oxalate aqueous solution.

[0016] Preferably, the mass concentration of the high-purity vanadium oxalate aqueous solution is 5-30%.

[0017] In a second aspect, the present invention also provides a high-purity vanadyl oxalate prepared according to the above preparation method, wherein the purity of the high-purity vanadyl oxalate is above 99.5%.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The preparation method of high-purity vanadyl oxalate provided by the present invention adopts a mechanochemical method to prepare high-purity vanadyl oxalate in one step, specifically, grinding vanadium pentoxide and oxalic acid at a high speed such as 500-5000 r / min.

[0019] It can be seen that the preparation method provided by the present invention has a rapid process, simple procedures, mild conditions, and strong scalability. It can not only obtain a high-purity vanadyl oxalate solid product (with a purity of more than 99.5%), but also obtain a high-purity vanadyl oxalate solution product by simply mixing the high-purity vanadyl oxalate solid product with water, and is suitable for large-scale production. Compared with the prior art using oxalic acid and vanadium pentoxide for aqueous phase reaction, it avoids complicated post-processing steps such as filtration, concentration, crystallization and drying.

[0020] In summary, this preparation method breaks through the general thinking of ordinary technicians in the field, breaks the technical prejudice of traditional preparation of vanadium oxalate products, overcomes the shortcomings of existing synthesis or preparation of vanadium oxalate products, solves long-standing related technical problems, and achieves unexpected results. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the XRD spectrum of the high-purity vanadyl oxalate product prepared in Example 1. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In view of the problem that in the prior art, oxalic acid and vanadium pentoxide are reacted in water phase to obtain a vanadyl oxalate aqueous solution, which needs to undergo complicated post-treatment to obtain a solid product, the present invention provides a method for preparing high-purity vanadyl oxalate, comprising the following steps: Vanadium pentoxide and oxalic acid are ground at 500-5000 r / min, and high-purity vanadium oxalate is obtained after the two react.

[0024] In the present invention, the vanadium pentoxide is high-purity vanadium pentoxide. Specifically, the purity of the vanadium pentoxide is ≥99.5%.

[0025] The present invention has no particular limitation on the sources of the vanadium pentoxide and oxalic acid, which are generally commercially available products.

[0026] The present invention grinds vanadium pentoxide and oxalic acid at a high speed, preferably 500-5000 r / min, more preferably 1000-3000 r / min, and further preferably 1500-2000 r / min, so that the two overcome the energy barrier to undergo a redox reaction, thereby obtaining high-purity vanadium oxalate. In the present invention, the grinding is preferably performed in a high-speed grinder. The grinding time is generally 1-6 h, preferably 2-4 h.

[0027] In the present invention, during the grinding process, the mass ratio of vanadium pentoxide to oxalic acid is 1:1.8 to 1:2.5, preferably 1:1.9 to 1:2.2.

[0028] Generally, after grinding, the obtained high-purity vanadyl oxalate is in a paste state. Therefore, in some embodiments of the present invention, the grinding is followed by a drying step; the drying temperature is 60-100°C, preferably 70-90°C; the drying time is 1-24 h, preferably 5-20 h. After the drying, a powdery high-purity vanadyl oxalate solid product can be obtained.

[0029] After testing, the purity of the high-purity vanadyl oxalate solid product is above 99.5%.

[0030] In summary, the chemical principle of the above reaction is that oxalic acid and vanadium pentoxide react through mechanochemical reaction to generate vanadium oxalate. The reaction formula is as follows: H2C2O4·n H2O+V2O5→VOC2O4 x H2O+H2O+CO2↑ In the present invention, during the high-speed grinding process, as the reaction energy barrier is overcome under severe grinding or shearing conditions, the reaction between the two can proceed to the right, and the gas CO2 and / or water volatilizes with the reaction, thereby obtaining a high-purity vanadium oxalate paste or powder solid product.

[0031] In other embodiments of the present invention, after obtaining the high-purity vanadyl oxalate in paste or powder form, the high-purity vanadyl oxalate is preferably mixed with water to obtain a high-purity vanadyl oxalate aqueous solution product.

[0032] In the present invention, the water is preferably deionized water (RO grade), and the amount of the water can be adjusted as needed. Generally, the mass concentration of the high-purity vanadyl oxalate aqueous solution is 5-30%.

[0033] In order to further illustrate the present invention, the following examples are used to provide a detailed description. The purity of the high-purity vanadium pentoxide used in the following examples of the present invention is ≥99.5%.

[0034] Example 1 This embodiment provides a method for preparing high-purity vanadyl oxalate, using high-purity vanadium pentoxide and analytically pure oxalic acid as raw materials to prepare a high-purity vanadyl oxalate product by a mechanochemical method.

[0035] The specific steps include: (1) Take 100 g of high-purity vanadium pentoxide and 200 g of oxalic acid and add them into a high-speed grinder; (2) The grinding rate was adjusted to 2000 r / min and the open grinding time was 2 h; (3) Drying the powdered solid obtained in the above step (60°C, 20 h) to obtain a blue vanadium oxalate product.

[0036] XRD test was performed on the obtained blue vanadium oxalate product, and the results were as follows: Figure 1 As shown. Figure 1 It can be seen that the obtained vanadium oxalate has the same crystal form and spectrum as the product obtained by concentrated crystallization in the literature (Steel Vanadium Titanium, 2016, 37(3):56-59), but the process is simpler.

[0037] Example 2 This embodiment provides a method for preparing high-purity vanadyl oxalate, using high-purity vanadium pentoxide and analytically pure oxalic acid as raw materials to prepare a high-purity vanadyl oxalate product by a mechanochemical method.

[0038] The specific steps include: (1) Take 100 g of high-purity vanadium pentoxide and 210 g of oxalic acid and add them into a high-speed grinder; (2) The grinding rate was adjusted to 500 r / min and the open grinding time was 5 h; (3) Drying the powdered solid obtained in the above step (70°C, 15 h) to obtain a blue vanadium oxalate product.

[0039] Example 3 This embodiment provides a method for preparing high-purity vanadyl oxalate, using high-purity vanadium pentoxide and analytically pure oxalic acid as raw materials to prepare a high-purity vanadyl oxalate product by a mechanochemical method.

[0040] The specific steps include: (1) Take 100 g of high-purity vanadium pentoxide and 190 g of oxalic acid and add them into a high-speed grinder; (2) The grinding rate was adjusted to 4500 r / min and the open grinding time was 0.5 h; (3) Drying the powdered solid obtained in the above step (90°C, 10 h) to obtain a blue vanadium oxalate product.

[0041] Example 4 This embodiment provides a method for preparing high-purity vanadyl oxalate, using high-purity vanadium pentoxide and analytically pure oxalic acid as raw materials to prepare a high-purity vanadyl oxalate product by a mechanochemical method.

[0042] The specific steps include: (1) Take 1000 g of high-purity vanadium pentoxide and 1950 g of oxalic acid and add them into a high-speed grinder; (2) The grinding rate was adjusted to 1000 r / min and the grinding time was 4 h; (3) The vanadium oxalate obtained in the above step was added with 8 L of deionized water (RO grade) to obtain a blue vanadium oxalate aqueous solution product with a specific concentration. The obtained blue vanadium oxalate aqueous solution product was analyzed, and the results are shown in Table 1 below: Table 1 Solution vanadium content (wt%) Product pH Density(g / cc) 6.0 1.1 1.15 The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing high-purity vanadyl oxalate, characterized in that: The following steps are involved: Vanadium pentoxide and oxalic acid are ground at 500-5000 r / min, and high-purity vanadium oxalate is obtained after the two react.

2. The preparation method according to claim 1, characterized in that: The grinding speed is 1000-3000 r / min.

3. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of vanadium pentoxide to oxalic acid is 1:1.8 to 1:2.5; The purity of the vanadium pentoxide is ≥99.5%.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the vanadium pentoxide to oxalic acid is 1:1.9 to 1:2.

2.

5. The preparation method according to any one of claims 1 to 4, characterized in that The grinding time is 1 to 6 h.

6. The preparation method according to claim 5, characterized in that: The grinding time is 2 to 4 h.

7. The preparation method according to any one of claims 1 to 6, characterized in that The grinding step also includes a drying step; The drying temperature is 60-100° C. and the drying time is 1-24 h.

8. The preparation method according to any one of claims 1 to 7, characterized in that After obtaining the high-purity vanadyl oxalate, the high-purity vanadyl oxalate is mixed with water to obtain a high-purity vanadyl oxalate aqueous solution.

9. The preparation method according to claim 8, characterized in that: The mass concentration of the high-purity vanadyl oxalate aqueous solution is 5-30%.

10. The purity of the high-purity vanadyl oxalate prepared by the preparation method according to any one of claims 1 to 9 is above 99.5%.

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