Method for preparing vanadyl oxalate in batches at room temperature through pre-aging

Abstract

The invention discloses a method for preparing vanadyl oxalate in batches at room temperature through pre-aging, and belongs to the technical field of chemical engineering. The method comprises the following steps: uniformly mixing a vanadium source and oxalic acid according to the molar ratio of V to oxalic acid of (1: 2.5)-(1: 3.5), aging for 3-5 days, flattening the discharged material until the thickness is 1-5cm, spraying 20-40% by mass of water, reacting at room temperature and air-drying for 0.5-3 days, and finally crushing or grinding to obtain a light blue solid vanadyl oxalate product. According to the method, the solid-phase reaction temperature can be reduced to the room temperature by utilizing the aging, interfacial effect and time-temperature equivalence principle of the raw materials, lower-temperature, ultralow-energy-consumption and large-scale preparation of vanadyl oxalate is successfully realized, irritant oxalic acid steam volatilization is avoided, the preparation process is simple in procedure, mild in condition, ultralow in energy consumption and high in expansibility, and the method is suitable for industrial production. The method is suitable for large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical engineering, and in particular relates to a method for preparing vanadyl oxalate in large quantities under room temperature conditions with ultra-low energy consumption. Background Art

[0002] Vanadium is called "the MSG of modern industry" and is an important raw material indispensable for the development of modern industry, national defense and science and technology. Vanadium-based compounds have key uses in many fields such as metallurgy, catalysts, electronics, new energy and new materials. Vanadium oxalate (or vanadium oxalate) is a soluble low-priced organic vanadium compound, a basic chemical raw material, and an intermediate raw material for the preparation of high-performance vanadium products including vanadium dioxide. The common vanadium oxalate on the market is currently sold in the form of aqueous solution, with few solid products and high prices, especially high-purity solid products and liquid products are not easy to obtain. The currently publicly reported vanadium oxalate preparation method generally uses oxalic acid and vanadium pentoxide to react in an aqueous phase to generate a vanadium oxalate aqueous solution, and then filters the solid particles and adds water to adjust the concentration to obtain a vanadium oxalate solution product. Its solid vanadium oxalate product must undergo continuous heating and concentration, cooling and crystallization, separation and drying. However, heating and concentration consumes a lot of energy and takes a long time, and high-concentration vanadium oxalate is easily hydrolyzed, decomposed or carbonized, affecting product quality. The traditional solid phase reaction preparation method requires a higher reaction temperature to overcome the energy barrier required for the reaction. The reaction temperature is generally above 100°C (100-200°C), or stirring is required to ensure the complete reaction. However, higher temperatures can easily lead to the volatilization of oxalic acid or the decomposition and discoloration of vanadium oxalate. As the reaction pellets are reduced and the interface melts, the surface and interface effects can theoretically lead to a reduction in the reaction energy barrier. Therefore, the research and development of a method for preparing vanadium oxalate in large quantities under room temperature conditions with ultra-low energy consumption has become an important issue that needs to be solved urgently. Summary of the invention

[0003] In order to overcome the defects and limitations of the prior art, the purpose of the present invention is to provide a method for preparing vanadium oxalate in large quantities under room temperature conditions and with ultra-low energy consumption. The present invention can reduce the solid-phase reaction temperature to room temperature by utilizing the aging of raw materials, interface effects and the time-temperature equivalence principle, successfully achieving the lower temperature, ultra-low energy consumption and large-scale preparation of vanadium oxalate and avoiding the volatilization of irritating oxalic acid vapor. The preparation process has simple procedures, mild conditions, ultra-low energy consumption, strong scalability, and is suitable for large-scale production. The technology breaks through the general thinking of ordinary technicians, breaks the technical prejudice of traditional chemical preparation, overcomes the shortcomings of existing synthesis or preparation technology, solves long-standing related technical problems, and obtains unexpected results. It can be used for the preparation of a variety of vanadium products including vanadium dioxide, catalysts, and energy storage materials.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] The present invention provides a method for preparing vanadyl oxalate in large quantities under room temperature conditions with ultra-low energy consumption, comprising the following steps:

[0006] (1) mixing a vanadium source and oxalic acid at a molar ratio of vanadium to oxalic acid of 1:2.5 to 1:3.5, and aging at room temperature for 3 to 5 days;

[0007] (2) The material is scraped to a thickness of 1 to 5 cm, sprayed with 20 to 40% water by mass, reacted at room temperature and air-dried for 0.5 to 3 days;

[0008] (3) Crushing or grinding to obtain a light blue solid vanadium oxalate product.

[0009] Based on the above technical solution, further, the vanadium source described in step (1) includes vanadium pentoxide.

[0010] Based on the above technical solution, further, the particle size of the vanadium source described in step (1) is sub-millimeter powder.

[0011] Based on the above technical solution, further, the molar ratio of V in the vanadium source and oxalic acid to oxalic acid in step (1) is 1:2.8 to 1:3.1.

[0012] Based on the above technical solution, further, the room temperature conditions in step (1) and step (2) are 10 to 40°C, preferably 20 to 30°C.

[0013] Based on the above technical solution, further, the water described in step (2) is deionized water.

[0014] Based on the above technical solution, further, the reaction + air drying described in step (2) is carried out in a trough, tank or pool with a lining, the lining is an inert plastic film, ceramic film or composite film, and the material of the trough, tank or pool is cement, plastic, wood, metal or composite material.

[0015] The beneficial effects of the present invention compared with the prior art are as follows:

[0016] The present invention uses aging, that is, various raw materials are mixed uniformly under stirring, and then placed at room temperature for a period of time, so that various molecules slowly interact with each other and combine with each other to achieve the generation of intermediates, and finally form a light gel rather than large-sized grains. In comparison, the light gel is easier to air-dry in a short period of time, thereby achieving energy saving and cost reduction as well as uniform product quality (if no pre-aging is performed, the dark blue product obtained by direct room temperature reaction will be impure in phase, with needle-shaped oxalic acid precipitated, and the grain size and solid density will be larger; on the other hand, the natural air-drying time required will also be longer, requiring more than ten days or even dozens of days); the present invention reduces the solid-phase reaction temperature to room temperature by utilizing the aging of raw materials, interface effect and time-temperature equivalence principle, successfully achieves lower temperature, ultra-low energy consumption, large-scale preparation of vanadium oxalate and avoids the volatilization of irritating oxalic acid vapor, and therefore has important technical value and market prospects in the fields of vanadium chemical industry and vanadium-based new materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention, the drawings related to the embodiments are briefly introduced below.

[0018] Figure 1 This is the XRD spectrum of the solid vanadyl oxalate product prepared in Example 1 of the present invention.

[0019] Figure 2 The following is the XRD spectrum of vanadium pentoxide, a raw material of an embodiment of the present invention.

[0020] Figure 3 The figure is the XRD pattern of oxalic acid, a raw material of the embodiment of the present invention.

[0021] Figure 4 The figure is a comparison of the XRD spectra of the raw material (vanadium pentoxide + oxalic acid mixture) of the embodiment of the present invention before and after aging.

[0022] Figure 5 This is a macroscopic comparison of the block-like solid vanadium oxalate obtained after pre-aging (Example 1) and without pre-aging (Comparative Example 1). DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Obviously, the embodiments described below are only partial embodiments of the present invention. For those skilled in the art, other similar embodiments obtained without creative labor all fall within the protection scope of the present invention.

[0024] The present invention provides a method for preparing vanadyl oxalate in large quantities under room temperature conditions with ultra-low energy consumption, comprising the following steps:

[0025] (1) mixing a vanadium source and oxalic acid at a molar ratio of vanadium to oxalic acid of 1:2.5 to 1:3.5, and aging for 3 to 5 days;

[0026] (2) The material is scraped to a thickness of 1 to 5 cm, sprayed with 20 to 40% water by mass, reacted at room temperature and air-dried for 0.5 to 3 days;

[0027] (3) Crushing or grinding to obtain a light blue solid vanadium oxalate product.

[0028] The chemical principle of preparing vanadyl oxalate in the present invention is that oxalic acid and vanadium pentoxide generate vanadyl oxalate through aging reaction and time-temperature equivalence principle. The reaction formula is as follows:

[0029] H2C2O4·nH2O+V2O5→VOC2O4·xH2O+H2O+CO2↑(room temperature and atmospheric conditions)

[0030] As the reaction proceeds to the right, the gas and water gradually evaporate, and a light blue vanadyl oxalate paste or solid product is obtained.

[0031] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0032] Example 1

[0033] A method for preparing vanadyl oxalate in batches under room temperature conditions and with ultra-low energy consumption comprises the following steps:

[0034] (1) mixing submillimeter powdered vanadium pentoxide and oxalic acid at a molar ratio of vanadium pentoxide to oxalic acid of 1:3, and aging at room temperature for 3 days;

[0035] (2) The material was scraped to a thickness of 4 cm, sprayed with 20% by mass deionized water, reacted at room temperature and air-dried for 2 days;

[0036] (3) Crushing or grinding to obtain a light blue solid vanadium oxalate product with a purity of ≥99.5% and a conversion rate of 100%.

[0037] The XRD spectrum of the solid vanadyl oxalate product prepared in this example is as follows Figure 1 As shown, the XRD spectrum of the raw material vanadium pentoxide in the embodiment is as follows Figure 2 As shown, the XRD pattern of the raw material oxalic acid in the embodiment is as follows Figure 3 As shown, the XRD patterns of the raw material (vanadium pentoxide + oxalic acid mixture) before and after aging are as follows Figure 4 As shown in the figure, by comparison, it can be seen that the vanadium pentoxide and oxalic acid in this example react to prepare vanadium oxalate, and a brown-green intermediate is generated by chemical reaction before and after aging. Moreover, the macroscopic images of the solid vanadium oxalate obtained after pre-aging and without pre-aging are obviously different, as shown in FIG. Figure 5As shown (the left side is pre-aged, and the reaction + natural air drying takes about 3 days in total, and the right side is not pre-aged; the reaction + natural air drying takes about 10 days in total). The product obtained after pre-aging is light blue, light, delicate, easy to powder, and has uniform color; while the product obtained without aging is dark blue, with high density, hard and brittle texture, uneven color, white or transparent oxalic acid crystals precipitated, and the XRD spectrum is different. This is also related to the phenomenon and mechanism of the reaction + air drying process. After pre-aging, the obtained sol is dispersed in a uniform phase, and finally forms a loose and lightweight structure, which is easier to air dry; while without pre-aging, the vanadium oxalate and oxalic acid are finally precipitated and precipitated in the form of larger crystals, which are prone to solid-liquid stratification and phase separation. The reduced evaporation area also causes the air drying process to slow down significantly.

[0038] Comparative Example 1

[0039] A method for preparing vanadyl oxalate comprises the following steps:

[0040] (1) mixing submillimeter powdered vanadium pentoxide and oxalic acid in a molar ratio of vanadium pentoxide to oxalic acid of 1:3, adding 20% ​​by mass of deionized water to obtain wet powder, flattening to a thickness of 4 cm, reacting and air-drying for 10 days;

[0041] (2) Crushing or grinding to obtain a dark blue solid product.

[0042] Example 2

[0043] A method for preparing vanadyl oxalate in batches under room temperature conditions and with ultra-low energy consumption comprises the following steps:

[0044] (1) mixing submillimeter powdered vanadium pentoxide and oxalic acid at a molar ratio of vanadium pentoxide to oxalic acid of 1:3.1, and aging at room temperature for 5 days;

[0045] (2) The material was scraped to a thickness of 3 cm, sprayed with 40% by mass deionized water, reacted at room temperature and air-dried for 2 days;

[0046] (3) Crushing or grinding to obtain a light blue solid vanadium oxalate product.

[0047] Example 3

[0048] A method for preparing vanadyl oxalate in batches under room temperature conditions and with ultra-low energy consumption comprises the following steps:

[0049] (1) mixing submillimeter powdered vanadium pentoxide and oxalic acid at a molar ratio of vanadium pentoxide to oxalic acid of 1:2.8, and aging at room temperature for 4 days;

[0050] (2) The material was scraped to a thickness of 5 cm, sprayed with 30% by mass deionized water, reacted at room temperature and air-dried for 2 days;

[0051] (3) The obtained light blue solid vanadium oxalate product is mixed with a certain amount of deionized water to obtain a vanadium oxalate aqueous solution of a specific concentration (eg, 6%).

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing vanadyl oxalate in large quantities, characterized in that: The steps include: (1) mixing a vanadium source and oxalic acid at a molar ratio of vanadium to oxalic acid of 1:2.5 to 1:3.5, and aging at room temperature for 3 to 5 days; (2) The material is scraped to a thickness of 1 to 5 cm, sprayed with 20 to 40% water by mass, reacted at room temperature and air-dried for 0.5 to 3 days; (3) Crushing or grinding to obtain a light blue solid vanadium oxalate product.

2. The method according to claim 1, characterized in that The vanadium source described in step (1) includes vanadium pentoxide.

3. The method according to claim 1, characterized in that The particle size of the vanadium source described in step (1) is sub-millimeter powder.

4. The method according to claim 1, characterized in that: The molar ratio of V in the vanadium source and oxalic acid to oxalic acid in step (1) is 1:2.8 to 1:3.

1.

5. The method according to claim 1, characterized in that The room temperature conditions in step (1) and step (2) are 10 to 40°C, preferably 20 to 30°C.

6. The method according to claim 1, characterized in that The water described in step (2) is deionized water.

7. The method according to claim 1, characterized in that The reaction + air drying described in step (2) is carried out in a trough, tank or pool with a lining, the lining is an inert plastic film, a ceramic film or a composite film, and the material of the trough, tank or pool is cement, plastic, wood, metal or a composite material.

Images