Method for preparing vanadyl sulfate

Abstract

The invention discloses a method for preparing vanadyl sulfate, which comprises the following steps: (1) mixing V2O5, concentrated sulfuric acid and distilled water in a reactor to obtain mixed slurry; (2) adding an organic reducing agent into the reactor, adjusting the reaction temperature, and carrying out an incomplete reduction reaction; (3) adding an inorganic reducing agent into the reactor, and carrying out complete reduction reaction to obtain a vanadyl sulfate solution after complete reaction; and (4) carrying out post-treatment on the vanadyl sulfate solution to obtain vanadyl sulfate crystals. According to the method, the adding sequence and adding amount of the organic reducing agent and the inorganic reducing agent are adjusted, the technical problem that the quality of vanadyl sulfate is reduced due to the fact that organic matter residues are serious when organic matter is adopted as the reducing agent is solved, and the problems that when inorganic matter is adopted as the reducing agent, reaction time is long, reaction is slow, and the like are solved. And the conversion rate is low. The method provided by the invention can be used for preparing vanadyl sulfate with low organic matter content, high purity and wide applicability.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a method for preparing vanadyl sulfate. Background Art

[0002] As a multifunctional chemical substance, vanadyl sulfate has a wide range of applications. In the textile industry, it acts as a mordant to significantly improve the adhesion and color saturation of dyes, making fabric colors more vivid and lasting. In the field of chemical synthesis, vanadyl sulfate demonstrates its unique advantages as a catalytic reducing agent, effectively promoting a variety of redox reactions. In addition, in the ceramic and glass manufacturing industries, it acts as a colorant, adding a rich variety of color options to products, meeting the market's demand for beauty and personalization. In the field of scientific research, vanadyl sulfate has attracted much attention, especially in diabetes research, where it serves as a potential reagent for improving insulin sensitivity, providing new ideas and directions for the treatment of diabetes.

[0003] In the preparation process of vanadium sulfate solution, it is crucial to choose a suitable process method. Although the sulfur dioxide reduction method of the prior art is widely used, it faces challenges such as low conversion rate, great safety hazards and environmental pressure. The limited solubility of sulfur dioxide in a strong acid environment limits the reaction efficiency. At the same time, the storage of a large number of sulfur dioxide cylinders also increases the safety risk of the production site, posing a potential threat to environmental protection. To overcome these shortcomings, the use of organic matter as a reducing agent has become a new exploration direction. This method hopes to achieve an efficient and environmentally friendly preparation process of vanadium sulfate solution by accurately controlling the amount of organic reducing agent added. However, in actual production, it is impossible to accurately control the amount of organic reducing agent added to ensure that the reduction reaction is completely carried out when the organic reducing agent is almost completely consumed and there is less residue. This is because: in the large-scale production process, on the one hand, the raw material composition fluctuates greatly, and on the other hand, the feeding accuracy is low, which makes it difficult to accurately control the amount of reducing agent added, which is not conducive to industrial production. Organic residues will affect the product quality of vanadium sulfate. Vanadyl sulfate can be used in vanadium electrolytes. Excessive organic residues will reduce the electrochemical properties (such as service life) of the electrolyte. In summary, excessive organic reducing agent due to incomplete reaction will cause organic matter to remain, which will eventually affect the quality of the product. If the organic reducing agent is not added enough, the reaction will be incomplete, which will also damage the quality of the finished product.

[0004] Therefore, optimizing the reducing agent addition strategy and ensuring precise control of the reaction process are important ways to improve the efficiency and quality of vanadyl sulfate preparation. However, the existing technology still has a lot of room for improvement in these aspects. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing vanadyl sulfate.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for preparing vanadyl sulfate, which comprises the following steps: (1) V2O5, concentrated sulfuric acid and distilled water are placed in a reactor and mixed to obtain a mixed slurry; (2) adding an organic reducing agent to the reactor and adjusting the reaction temperature to perform an incomplete reduction reaction; (3) adding an inorganic reducing agent to the reactor to carry out a complete reduction reaction, and obtaining a vanadyl sulfate solution after the reaction is complete; (4) Post-treating the vanadyl sulfate solution to obtain vanadyl sulfate crystals.

[0007] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, in step (1), the purity of V2O5 is >98%, the mass fraction of concentrated sulfuric acid is ≥90%, and the molar ratio of V2O5 to concentrated sulfuric acid is 1:(1.0-2.52).

[0008] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, in step (2), the amount of organic reducing agent added is determined according to the consumption of V2O5; in step (3), the amount of inorganic reducing agent added is determined according to the remaining amount of V2O5.

[0009] In an embodiment of the method for preparing vanadium oxysulfate described in the present invention, the consumption of the reactant V2O5 in step (2) is 60%-98%, and when the consumption of V2O5 is 60%-98%, an inorganic reducing agent is added to the reactor in step (3) to carry out a complete reduction reaction.

[0010] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, in step (2), the organic reducing agent is oxalic acid, and the molar ratio of V2O5 to oxalic acid is 1:(0.6-0.98).

[0011] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, in step (2), the reduction temperature is 70°C-100°C, and the reduction time is 2h-8h; in step (3), the reduction temperature is room temperature, and the reduction time is 2h-10h.

[0012] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, in step (3), the inorganic reducing agent is one of sulfur dioxide, sulfurous acid, and vanadium trioxide.

[0013] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, during the reaction process of step (3), the steps of measuring the temperature and pressure inside the reactor and observing the color and mixing state of the reaction products are also included to determine whether the reaction is complete.

[0014] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, in step (4), post-treatment includes the steps of steam heating, concentrating, crystallizing and filtering the vanadyl sulfate solution, and then obtaining filtered vanadyl sulfate crystals, wherein the time of steam heating, concentrating and crystallizing is 1h-6h, the temperature of concentrating and crystallizing is 70°C-90°C, the solid-liquid ratio of the vanadyl sulfate slurry obtained by distillation is 50%-90%, and the filtration is performed through a plate and frame filter.

[0015] In an embodiment of the method for preparing vanadyl sulfate described in the present invention, the filtered vanadyl sulfate crystals are dried to obtain vanadyl sulfate crystals, wherein the drying temperature is 60° C.-95° C. and the drying time is 4 h-12 h.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are: The method of the present invention first introduces an organic substance as a reducing agent into the reaction system to allow the reduction reaction to proceed to between 60% and 98%. The second step is to introduce an inorganic substance as a reducing agent into the reaction system to allow the reduction reaction to proceed thoroughly. Through the above technical scheme of adjusting the order and amount of addition of the organic reducing agent and the inorganic reducing agent, the technical problem of serious organic residue and reduced quality of vanadium sulfate when the organic substance is used as the reducing agent is solved, and the technical problem of long reaction time, slow reaction and low conversion rate when the inorganic substance is used as the reducing agent is solved.

[0017] The method of the present invention can prepare vanadyl sulfate with low residual organic matter content, high purity and wide applicability. The method of the present invention reduces production costs and safety and environmental protection risks. The price and transportation cost of organic acid are low, which is conducive to storage, rapid reaction, and conducive to improving production efficiency. At the same time, it can effectively reduce the storage and purchase amount of inorganic substances, which helps to reduce safety and environmental protection risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0019] Figure 1 The present invention is a schematic flow chart of the method for preparing vanadyl sulfate. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0021] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0022] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0023] like Figure 1 As shown, the present invention provides a method for preparing vanadium oxysulfate, which comprises the following steps: (1) V2O5, concentrated sulfuric acid and distilled water are placed in a reactor and mixed to obtain a mixed slurry.

[0024] (2) Add the organic reducing agent oxalic acid (C2H2O4▪2H2O, analytical grade) into the reactor and adjust the reaction temperature to carry out an incomplete reduction reaction.

[0025] (3) Adding an inorganic reducing agent into the reactor to carry out a complete reduction reaction, and obtaining a vanadyl sulfate solution after the reaction is complete.

[0026] (4) Post-treating the vanadyl sulfate solution to obtain vanadyl sulfate crystals.

[0027] In one embodiment, in step (1), the purity of V2O5 is >98%, the mass fraction of concentrated sulfuric acid is ≥90%, and the molar ratio of V2O5 to concentrated sulfuric acid is 1:(1.0-2.52).

[0028] In one embodiment, in step (2), the amount of oxalic acid added is determined according to the consumption of V2O5, and the molar ratio of V2O5 to oxalic acid is 1:(0.6-0.98); in step (3), the amount of inorganic reducing agent added is determined according to the remaining amount of V2O5.

[0029] In one embodiment, the consumption of the reactant V2O5 in step (2) is 60%-98%, and when the consumption of V2O5 is 60%-98%, an inorganic reducing agent is added to the reactor in step (3) to perform a complete reduction reaction.

[0030] It should be understood by those skilled in the art that the reduction rate of vanadium pentoxide can be determined by detecting the concentration of tetravalent vanadium in the solution. For example, when vanadium pentoxide is completely reacted, the concentration of tetravalent vanadium is 2 mol / L (the theoretical reaction product can be calculated based on the amount of vanadium pentoxide added and the liquid volume), so the concentration of tetravalent vanadium in the solution will be lower than 2 mol / L when the reaction is not complete. Therefore, by measuring the concentration of tetravalent vanadium in the solution, the consumption of V2O5 can be calculated, and then it can also be determined whether the reaction is complete.

[0031] In one embodiment, in step (2), the reduction temperature is 70°C-100°C, and the reduction time is 2h-8h; in step (3), the reduction temperature is room temperature, and the reduction time is 2h-10h.

[0032] In one embodiment, in step (3), the inorganic reducing agent is one of sulfur dioxide, sulfurous acid, and vanadium trioxide.

[0033] In one embodiment, the reaction process of step (3) also includes the steps of measuring the temperature and pressure inside the reactor and observing the color and mixing state of the reaction products to comprehensively determine whether the reaction is complete.

[0034] Since the reaction for preparing vanadyl sulfate is an exothermic reaction, the temperature in the reactor, such as the reactor, rises first during the reaction, then stabilizes, and after the reaction is complete, the temperature begins to decrease. At the same time, the pressure in the reactor changes during the reaction. For example, when sulfur dioxide is used as a reducing agent, the solubility of sulfur dioxide gas in the liquid decreases after the reaction is complete, and it is in the form of gas in the reactor. When the pressure in the reactor begins to rise, it indicates that the reaction is complete. Therefore, a temperature measuring device and a pressure measuring device can be set on the reactor. By measuring the temperature and pressure inside the reactor, and then observing the temperature change and pressure change in the reactor, it is possible to effectively determine whether the reaction is complete.

[0035] In addition, the color and mixing state of the reaction product will change before and after the reaction is complete, and the color will change from a yellow-blue mixture to blue, and from a solid-liquid mixed slurry to a pure liquid, thereby judging whether the reaction is complete. It should be understood by those skilled in the art that the presence of excess sulfurous acid will not affect the quality of the final product, and the presence of excess vanadium trioxide can be removed by filtering, which will also not affect the quality of the final product.

[0036] In one embodiment, in step (4), post-treatment includes the steps of steam heating, concentrating, crystallizing and filtering the vanadyl sulfate solution, and then obtaining filtered vanadyl sulfate crystals, wherein the steam heating, concentrating and crystallizing time is 1h-6h, the concentrating and crystallizing temperature is 70°C-90°C, the solid-liquid ratio of the vanadyl sulfate slurry obtained by distillation is 50%-90%, and the slurry is filtered through a plate and frame filter.

[0037] In one embodiment, the filtered vanadyl sulfate crystals are dried to obtain vanadyl sulfate crystals, wherein the drying temperature is 60° C.-95° C., and the drying time is 4 h-12 h.

[0038] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0039] Example 1 (1) 300 kg of vanadium pentoxide with a purity of 99.6%, 161 kg of concentrated sulfuric acid with a mass fraction of 98%, and distilled water were placed in a reactor and mixed to obtain a mixed slurry.

[0040] (2) Add 180 kg of oxalic acid into the reactor to carry out an incomplete reduction reaction, wherein the consumption of vanadium pentoxide is 85%. The reduction temperature is 70°C and the reduction time is 5 hours.

[0041] (3) An excess amount of sulfur dioxide gas is introduced into the reactor for reduction reaction. The reduction temperature is room temperature and the reduction time is 6 hours. The temperature in the reactor rises first, then stabilizes. After the reaction is complete, the temperature begins to decrease. The pressure in the reactor begins to rise, indicating that the reaction is complete, and finally a vanadyl sulfate solution is obtained.

[0042] (4) The vanadyl sulfate solution was steam-heated and concentrated and crystallized at 80°C for 1 hour to obtain a vanadyl sulfate solid-liquid mixture with a solid-liquid ratio of 50%, which was filtered through a plate and frame filter press and then dried at 60°C for 12 hours to obtain vanadyl sulfate.

[0043] The reduction rate of vanadium pentoxide is 97%, and the mass fraction of residual oxalic acid in the obtained product is 0.05%.

[0044] Example 2 (1) 300 kg of vanadium pentoxide with a purity of 99.7%, 180 kg of concentrated sulfuric acid with a mass fraction of 98%, and distilled water are placed in a reactor and mixed to obtain a mixed slurry.

[0045] (2) Add 125 kg of oxalic acid solution into the reactor to carry out an incomplete reduction reaction, wherein the consumption of vanadium pentoxide is 60%. The reduction temperature is 80°C and the reduction time is 2 h.

[0046] (3) Add sufficient sulfurous acid to the reactor for reduction reaction until the solution turns dark blue and there is no suspended solid. The reduction temperature is room temperature and the reduction time is 10 h to obtain a vanadyl sulfate solution.

[0047] (4) The vanadyl sulfate solution was steam-heated and concentrated and crystallized at 90°C for 6 hours to obtain a vanadyl sulfate solid-liquid mixture with a solid-liquid ratio of 86%, which was filtered through a plate and frame filter press and then dried at 80°C for 8 hours to obtain vanadyl sulfate.

[0048] The reduction rate of vanadium pentoxide was 96%, and the mass fraction of residual oxalic acid in the obtained product was 0.01%.

[0049] Example 3 (1) 300 kg of vanadium pentoxide with a purity of 99.7%, 408 kg of concentrated sulfuric acid with a mass fraction of 98%, and distilled water were placed in a reactor and mixed to obtain a mixed slurry.

[0050] (2) Add 203 kg of oxalic acid into the reactor to carry out an incomplete reduction reaction. The consumption of vanadium pentoxide is 98%. The reduction temperature is 100 °C and the reduction time is 8 hours.

[0051] (3) Add 30 kg of vanadium trioxide (purity: 99.6%) into the reactor for reduction reaction at room temperature for 2 h to obtain a vanadium sulfate solution.

[0052] (4) The vanadyl sulfate solution is steam-heated, concentrated and crystallized at 70°C for 6 hours to obtain a vanadyl sulfate solid-liquid mixture with a solid-liquid ratio of 90%, which is filtered through a plate and frame filter press and then dried at 70°C for 6 hours to obtain vanadyl sulfate.

[0053] The reduction rate of vanadium pentoxide is 95%, and the mass fraction of residual oxalic acid in the obtained product is 0.03%.

[0054] Comparative Example 1 (using a single organic reducing agent) (1) 300 kg of vanadium pentoxide with a purity of 99.7%, 180 kg of concentrated sulfuric acid with a mass fraction of 98%, and distilled water are placed in a reactor and mixed to obtain a mixed slurry.

[0055] (2) Add 208 kg of oxalic acid solution into the reactor for reduction reaction. The reduction temperature is 90°C and the reduction time is 9 hours. After the reaction is complete, the solution is dark blue with no suspended solids.

[0056] (3) The vanadyl sulfate solution was steam-heated and concentrated and crystallized at 90°C for 6 hours to obtain a vanadyl sulfate solid-liquid mixture with a solid-liquid ratio of 86%, which was filtered through a plate and frame filter press and then dried at 80°C for 8 hours to obtain vanadyl sulfate.

[0057] The reduction rate of vanadium pentoxide was 98%, and the mass fraction of residual oxalic acid in the obtained product was 3.5%.

[0058] Comparative Example 2 (using a single inorganic reducing agent) (1) 300 kg of vanadium pentoxide with a purity of 99.7%, 180 kg of concentrated sulfuric acid with a mass fraction of 98%, and distilled water are placed in a reactor and mixed to obtain a mixed slurry.

[0059] (2) A sufficient amount of sulfur dioxide gas is introduced into the reactor to carry out a reduction reaction. The reduction temperature is room temperature and the reduction time is 24 hours. After the reaction is complete, the solution is dark blue with no suspended solids.

[0060] (3) The vanadyl sulfate solution was steam-heated and concentrated and crystallized at 90°C for 6 hours to obtain a vanadyl sulfate solid-liquid mixture with a solid-liquid ratio of 86%, which was filtered through a plate and frame filter press and then dried at 80°C for 8 hours to obtain vanadyl sulfate.

[0061] The reduction rate of vanadium pentoxide is 76%. Compared with the case where a mixed reducing agent is used for reduction in Examples 1-3, the reduction time of Comparative Example 2 is 24 hours, which is 13 hours, 12 hours, and 14 hours longer than the reduction time in Examples 1-3, respectively.

[0062] It should be particularly pointed out that the various components or steps in the above-mentioned embodiments can be cross-linked, replaced, added, or deleted with each other. Therefore, the combinations formed by these reasonable arrangements and combinations should also fall within the scope of protection of the present invention, and the scope of protection of the present invention should not be limited to the embodiments.

[0063] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for preparing vanadyl sulfate, characterized in that: The method comprises the following steps: (1) V2O5, concentrated sulfuric acid and distilled water are placed in a reactor and mixed to obtain a mixed slurry; (2) adding an organic reducing agent to the reactor and adjusting the reaction temperature to perform an incomplete reduction reaction; (3) adding an inorganic reducing agent to the reactor to carry out a complete reduction reaction, and obtaining a vanadyl sulfate solution after the reaction is complete; (4) Post-treating the vanadyl sulfate solution to obtain vanadyl sulfate crystals.

2. The method for preparing vanadyl sulfate according to claim 1, characterized in that: In step (1), the purity of V2O5 is >98%, the mass fraction of concentrated sulfuric acid is ≥90%, and the molar ratio of V2O5 to concentrated sulfuric acid is 1:(1.0-2.52).

3. The method for preparing vanadyl sulfate according to claim 1, characterized in that: In step (2), the amount of organic reducing agent to be added is determined according to the amount of V2O5 consumed; in step (3), the amount of inorganic reducing agent to be added is determined according to the amount of V2O5 remaining.

4. The method for preparing vanadyl sulfate according to claim 3, characterized in that: The consumption of the reactant V2O5 in step (2) is 60%-98%, and when the consumption of V2O5 is 60%-98%, an inorganic reducing agent is added to the reactor in step (3) to perform a complete reduction reaction.

5. The method for preparing vanadyl sulfate according to claim 1, characterized in that: In step (2), the organic reducing agent is oxalic acid, and the molar ratio of V2O5 to oxalic acid is 1:(0.6-0.98).

6. The method for preparing vanadyl sulfate according to claim 1, characterized in that: In step (2), the reduction temperature is 70°C-100°C, and the reduction time is 2h-8h; in step (3), the reduction temperature is room temperature, and the reduction time is 2h-10h.

7. The method for preparing vanadyl sulfate according to claim 1, characterized in that: In step (3), the inorganic reducing agent is one of sulfur dioxide, sulfurous acid, and vanadium trioxide.

8. The method according to claim 1, characterized in that The reaction process of step (3) also includes the steps of measuring the temperature and pressure inside the reactor and observing the color and mixing state of the reaction products to determine whether the reaction is complete.

9. The method for preparing vanadyl sulfate according to claim 1, characterized in that: In step (4), post-treatment includes the steps of steam heating, concentrating, crystallizing and filtering the vanadyl sulfate solution, and then obtaining filtered vanadyl sulfate crystals, wherein the steam heating, concentrating and crystallizing time is 1h-6h, the concentrating and crystallizing temperature is 70°C-90°C, the solid-liquid ratio of the vanadyl sulfate slurry obtained by distillation is 50%-90%, and the slurry is filtered through a plate and frame filter.

10. The method for preparing vanadyl sulfate according to claim 8, characterized in that: The filtered vanadyl sulfate crystals are dried to obtain vanadyl sulfate crystals, wherein the drying temperature is 60° C.-95° C., and the drying time is 4 h-12 h.

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