A method for preparing vanadium pentoxide with ammonium metavanadate

Abstract

A method for preparing vanadium pentoxide by using ammonium metavanadate, comprising the following steps: (1) preparation of an oxidant loaded with ozone and chloromethyl polystyrene resin of graphene oxide; (2) heating and dissolving crude ammonium metavanadate in water, adjusting the pH value to 8-9 by using a sodium hydroxide solution after dissolving, filtering to obtain a sodium metavanadate solution; (3) heating the sodium metavanadate solution to 60-80 DEG C, adding the oxidant loaded with ozone and chloromethyl polystyrene resin of graphene oxide, stirring for more than 20 minutes, filtering to obtain a filtrate; (4) adding ammonium metavanadate crystals to the obtained filtrate for recrystallization, obtaining ammonium metavanadate precipitate, and performing solid-liquid separation and drying to obtain ammonium metavanadate crystals; (5) calcining the ammonium metavanadate crystals to obtain vanadium pentoxide. The purity of the obtained vanadium pentoxide is greater than or equal to 99.99%, and the sum of the content of tetravalent vanadium and trivalent vanadium is less than or equal to 0.003%.

Description

Technical Field

[0001] This invention relates to the field of high-priced vanadium production technology, and in particular to a method for preparing vanadium pentoxide using ammonium metavanadate. Background Technology

[0002] Ammonium metavanadate, with the molecular formula NH4VO3, is a white or slightly yellowish crystalline powder with a relative density of 2.326 and a molecular weight of 116.98. It is slightly soluble in cold water, hot ethanol, and diethyl ether, and soluble in hot water and dilute ammonium hydroxide. When burned in air, it transforms into vanadium pentoxide.

[0003] Ammonium metavanadate is an intermediate product in vanadium refining, mainly used to produce vanadium pentoxide (powder or flakes), which is then further used to produce metallic vanadium, ferrovanadium alloys, or other vanadium-based alloys. It can also be used as a chemical reagent, catalyst, drying agent, and mordant. In the ceramics industry, it is widely used as a glaze.

[0004] Vanadium is an important strategic reserve metal with a wide range of applications. It can be added to metals such as steel to enhance their performance, and it can also be used as a battery material in the preparation of high-density energy storage materials such as vanadium batteries. It is an indispensable raw material in aerospace, energy engineering, biomedicine, and metal processing. Metallic vanadium is mainly obtained through the reduction of vanadium compounds such as vanadium pentoxide. In recent years, with technological advancements, the industrial production of some downstream high-end vanadium technology products has placed higher demands on the quality of vanadium compounds, especially vanadium pentoxide. Particularly with the development of vanadium batteries and vanadium energy storage equipment, the domestic supply of high-purity vanadium pentoxide is far from meeting market demand, relying mainly on imports. Therefore, the production of high-purity vanadium pentoxide in my country has broad prospects, and the development of high-purity vanadium pentoxide production technology has significant application value and social significance.

[0005] Besides some common impurity metal ions, vanadium pentoxide also contains high levels of low-valent vanadium, such as tetravalent and trivalent vanadium. Currently, there are very few domestic manufacturers producing high-purity vanadium pentoxide, and their technology lags far behind that of foreign companies, resulting in inconsistent product quality. There are two main production processes for high-purity vanadium pentoxide: the first is deep purification of the vanadium-containing solution, and the second is calcination. However, both existing technologies suffer from high levels of low-valent vanadium, such as tetravalent and trivalent vanadium, in the final product, thus necessitating improvements to the calcination process. Summary of the Invention

[0006] 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 using ammonium metavanadate, resulting in vanadium pentoxide with high purity.

[0007] The technical solution adopted by this invention to solve its technical problem is a method for preparing vanadium pentoxide using ammonium metavanadate, comprising the following steps:

[0008] (a) Preparation of oxidizing agents:

[0009] (1) Add graphene oxide to chloromethyl polystyrene resin, and use ultrasonic dispersion and magnetic stirring for 20-150 min (preferably 30-60 min) to make it fully dispersed and uniform, so as to obtain a mixture;

[0010] Furthermore, in step (1), the mass ratio of graphene oxide to chloromethyl polystyrene resin is 1-5:1.

[0011] Furthermore, in step (1), the frequency of ultrasonic dispersion is 1.6 to 1.8 kHz.

[0012] Adjust the pH of the mixture obtained in step (1) to 8-9;

[0013] Furthermore, in step (2), the pH value is adjusted using an alkali, preferably sodium hydroxide or ammonia.

[0014] (3) Transfer the mixture whose pH value has been adjusted in step (2) to a high-pressure container, introduce ozone gas into the mixture, and keep it at a pressure of 500-800 kPa for 10-36 hours to obtain an oxidant, wherein the oxidant is a chloromethyl polystyrene resin loaded with ozone and graphene oxide.

[0015] (ii) Dissolve crude ammonium metavanadate in water by heating. After dissolving, adjust the pH value to 8-9 with sodium hydroxide solution, filter, and obtain sodium metavanadate solution.

[0016] In step (ii), some soluble impurities or impurities soluble in alkaline sodium hydroxide solution are removed to improve the purity of sodium metavanadate solution.

[0017] (iii) Heat the sodium metavanadate solution obtained in step (ii) to 60-80℃, add the chloromethyl polystyrene resin with ozone and graphene oxide loaded with oxidant prepared in step (i), stir and react for more than 20 minutes (preferably 30-60 minutes), filter, and take the filtrate.

[0018] Furthermore, in step (iii), the amount of oxidant added is sufficient to allow the low-valent vanadium, such as trivalent and tetravalent vanadium, in the sodium metavanadate solution to fully react and generate pentavalent vanadium. Specifically, generally, the amount of oxidant added is equivalent to 0.1-10% (preferably 1-5%) of the weight of the crude ammonium metavanadate in step (ii).

[0019] Studies have shown that ozone and graphene oxide can oxidize low-valent vanadium in sodium metavanadate solution to high-valent vanadium, improving the yield and recovery rate of vanadium and increasing the purity of vanadium pentoxide. Excessively high temperatures cause ozone to evaporate too quickly, hindering its oxidation of low-valent vanadium; conversely, excessively low temperatures result in a slow oxidation rate by both ozone and graphene oxide, also impeding complete oxidation of vanadium.

[0020] (iv) Add ammonium metavanadate crystals to the filtrate obtained in step (iii) for recrystallization to obtain ammonium metavanadate precipitate. Separate the solid and liquid and dry it to obtain ammonium metavanadate crystals.

[0021] (v) Calcining the ammonium metavanadate crystals obtained in step (iv) yields vanadium pentoxide.

[0022] Studies have shown that graphene oxide and ozone, after loading treatment, exhibit excellent oxidation performance. The combination of graphene oxide and ozone can rapidly oxidize low-valent vanadium, such as trivalent or tetravalent vanadium, in ammonium metavanadate solution to pentavalent vanadium, improving reaction activity and forming a stable structure to obtain the target product, thus increasing the purity of the final product, vanadium pentoxide. Chloromethyl polystyrene resin can be removed during recrystallization, and the gas generated after the ozone reaction is easily separated; graphene oxide can be separated by filtration. Without the loading of ozone and graphene oxide, it exhibits oxidative inertness and cannot fully exert its oxidation performance. This may be because ozone is easily decomposed and volatilized, while graphene oxide remains unactivated, resulting in relatively stable performance. This invention, using a loading method, not only solves the problem of easy ozone decomposition and volatilization but also addresses the issue of graphene oxide failing to react under certain conditions due to inactivation.

[0023] The vanadium pentoxide produced by this invention has high purity and few impurities, which fully meets the production requirements of some high-end products.

[0024] The purity of vanadium pentoxide obtained by this invention is ≥99.99%, wherein the sum of the contents of tetravalent vanadium and trivalent vanadium is ≤0.003%. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments. Example 1

[0026] The method for preparing vanadium pentoxide using ammonium metavanadate in this embodiment includes the following steps:

[0027] (a) Preparation of oxidizing agents:

[0028] (1) Add graphene oxide to chloromethyl polystyrene resin, and use ultrasonic dispersion and magnetic stirring for 30 min to make it fully dispersed and uniform, so as to obtain a mixture;

[0029] Furthermore, in step (1), the mass ratio of graphene oxide to chloromethyl polystyrene resin is 1:1.

[0030] Furthermore, in step (1), the frequency of ultrasonic dispersion is 1.6 to 1.8 kHz.

[0031] Adjust the pH of the mixture obtained in step (1) to 8;

[0032] Furthermore, in step (2), the pH value is adjusted using sodium hydroxide.

[0033] (3) The mixture whose pH value was adjusted in step (2) was transferred to a high-pressure container, ozone gas was introduced into the mixture, and it was kept at a pressure of 500 kPa for 36 hours to obtain an oxidant, wherein the oxidant is a chloromethyl polystyrene resin loaded with ozone and graphene oxide.

[0034] (ii) Dissolve crude ammonium metavanadate in water by heating. After dissolving, adjust the pH value to 8 with sodium hydroxide solution, filter, and obtain sodium metavanadate solution.

[0035] In step (ii), some soluble impurities or impurities soluble in alkaline sodium hydroxide solution are removed to improve the purity of sodium metavanadate solution.

[0036] (iii) Heat the sodium metavanadate solution obtained in step (ii) to 60°C, add the chloromethyl polystyrene resin loaded with ozone and graphene oxide prepared in step (i), stir and react for 30 minutes, filter, and take the filtrate.

[0037] Furthermore, in step (iii), the amount of oxidant added is sufficient to allow the low-valent vanadium, such as trivalent and tetravalent vanadium, in the sodium metavanadate solution to fully react and generate pentavalent vanadium. In this embodiment, the amount of oxidant added is equivalent to 1.0% of the weight of the crude ammonium metavanadate in step (ii).

[0038] Studies have shown that ozone and graphene oxide can oxidize low-valent vanadium in sodium metavanadate solution to high-valent vanadium, improving the yield and recovery rate of vanadium and increasing the purity of vanadium pentoxide. Excessively high temperatures cause ozone to evaporate too quickly, hindering its oxidation of low-valent vanadium; conversely, excessively low temperatures result in a slow oxidation rate by both ozone and graphene oxide, also impeding complete oxidation of vanadium.

[0039] (iv) Add ammonium metavanadate crystals to the filtrate obtained in step (iii) for recrystallization to obtain ammonium metavanadate precipitate. Separate the solid and liquid and dry it to obtain ammonium metavanadate crystals.

[0040] (v) Calcining the ammonium metavanadate crystals obtained in step (iv) yields vanadium pentoxide.

[0041] Studies have shown that graphene oxide and ozone, after loading treatment, exhibit excellent oxidation performance. The combination of graphene oxide and ozone can rapidly oxidize low-valent vanadium, such as trivalent or tetravalent vanadium, in ammonium metavanadate solution to pentavalent vanadium, improving reaction activity and forming a stable structure to obtain the target product, thus increasing the purity of the final product, vanadium pentoxide. Chloromethyl polystyrene resin can be removed during recrystallization, and the gas generated after the ozone reaction is easily separated; graphene oxide can be separated by filtration. Without the loading of ozone and graphene oxide, it exhibits oxidative inertness and cannot fully exert its oxidation performance. This may be because ozone is easily decomposed and volatilized, while graphene oxide remains unactivated, resulting in relatively stable performance. This invention, using a loading method, not only solves the problem of easy ozone decomposition and volatilization but also addresses the issue of graphene oxide failing to react under certain conditions due to inactivation.

[0042] The vanadium pentoxide produced by this invention has high purity and few impurities, which fully meets the production requirements of some high-end products.

[0043] The purity of vanadium pentoxide obtained by this invention is 99.990%, wherein the sum of the contents of tetravalent vanadium and trivalent vanadium is 0.002%. Example 2

[0044] The method for preparing vanadium pentoxide using ammonium metavanadate in this embodiment includes the following steps:

[0045] (a) Preparation of oxidizing agents:

[0046] (1) Add graphene oxide to chloromethyl polystyrene resin, and use ultrasonic dispersion and magnetic stirring for 60 min (preferably 30-60 min) to make it fully dispersed and uniform, so as to obtain a mixture;

[0047] Furthermore, in step (1), the mass ratio of graphene oxide to chloromethyl polystyrene resin is 5:1.

[0048] Furthermore, in step (1), the frequency of ultrasonic dispersion is 1.6 to 1.8 kHz.

[0049] Adjust the pH of the mixture obtained in step (1) to 9;

[0050] Furthermore, in step (2), the pH value is adjusted using alkaline ammonia water.

[0051] (3) The mixture whose pH value was adjusted in step (2) is transferred to a high-pressure container, ozone gas is introduced into the mixture, and it is kept at 800 kPa pressure for 10 h to obtain an oxidant, wherein the oxidant is a chloromethyl polystyrene resin loaded with ozone and graphene oxide.

[0052] (ii) Dissolve crude ammonium metavanadate in water by heating. After dissolving, adjust the pH value to 8 with sodium hydroxide solution, filter, and obtain sodium metavanadate solution.

[0053] In step (ii), some soluble impurities or impurities soluble in alkaline sodium hydroxide solution are removed to improve the purity of sodium metavanadate solution.

[0054] (iii) Heat the sodium metavanadate solution obtained in step (ii) to 80°C, add the chloromethyl polystyrene resin loaded with ozone and graphene oxide prepared in step (i), stir and react for 20 minutes, filter, and take the filtrate.

[0055] Furthermore, in step (iii), the amount of oxidant added is sufficient to allow the low-valent vanadium, such as trivalent and tetravalent vanadium, in the sodium metavanadate solution to fully react and generate pentavalent vanadium. In this embodiment, the amount of oxidant added is equivalent to 0.5% of the weight of the crude ammonium metavanadate in step (ii).

[0056] Studies have shown that ozone and graphene oxide can oxidize low-valent vanadium in sodium metavanadate solution to high-valent vanadium, improving the yield and recovery rate of vanadium and increasing the purity of vanadium pentoxide. Excessively high temperatures cause ozone to evaporate too quickly, hindering its oxidation of low-valent vanadium; conversely, excessively low temperatures result in a slow oxidation rate by both ozone and graphene oxide, also impeding complete oxidation of vanadium.

[0057] (iv) Add ammonium metavanadate crystals to the filtrate obtained in step (iii) for recrystallization to obtain ammonium metavanadate precipitate. Separate the solid and liquid and dry it to obtain ammonium metavanadate crystals.

[0058] (v) Calcining the ammonium metavanadate crystals obtained in step (iv) yields vanadium pentoxide.

[0059] Studies have shown that graphene oxide and ozone, after loading treatment, exhibit excellent oxidation performance. The combination of graphene oxide and ozone can rapidly oxidize low-valent vanadium, such as trivalent or tetravalent vanadium, in ammonium metavanadate solution to pentavalent vanadium, improving reaction activity and forming a stable structure to obtain the target product, thus increasing the purity of the final product, vanadium pentoxide. Chloromethyl polystyrene resin can be removed during recrystallization, and the gas generated after the ozone reaction is easily separated; graphene oxide can be separated by filtration. Without the loading of ozone and graphene oxide, it exhibits oxidative inertness and cannot fully exert its oxidation performance. This may be because ozone is easily decomposed and volatilized, while graphene oxide remains unactivated, resulting in relatively stable performance. This invention, using a loading method, not only solves the problem of easy ozone decomposition and volatilization but also addresses the issue of graphene oxide failing to react under certain conditions due to inactivation.

[0060] The vanadium pentoxide produced by this invention has high purity and few impurities, which fully meets the production requirements of some high-end products.

[0061] The purity of vanadium pentoxide obtained by this invention is 99.991%, wherein the sum of the contents of tetravalent vanadium and trivalent vanadium is 0.003%. Example 3

[0062] The method for preparing vanadium pentoxide using ammonium metavanadate in this embodiment includes the following steps:

[0063] (a) Preparation of oxidizing agents:

[0064] (1) Add graphene oxide to chloromethyl polystyrene resin, and use ultrasonic dispersion and magnetic stirring for 20 min to make it fully dispersed and uniform, so as to obtain a mixture;

[0065] Furthermore, in step (1), the mass ratio of graphene oxide to chloromethyl polystyrene resin is 2:1.

[0066] Furthermore, in step (1), the frequency of ultrasonic dispersion is 1.6 to 1.8 kHz.

[0067] Adjust the pH of the mixture obtained in step (1) to 9;

[0068] Furthermore, in step (2), the pH value is adjusted using sodium hydroxide.

[0069] (3) The mixture whose pH value was adjusted in step (2) was transferred to a high-pressure container, ozone gas was introduced into the mixture, and it was kept at a pressure of 600 kPa for 25 h to obtain an oxidant, wherein the oxidant is a chloromethyl polystyrene resin loaded with ozone and graphene oxide.

[0070] (ii) Dissolve crude ammonium metavanadate in water by heating. After dissolving, adjust the pH value to 8 with sodium hydroxide solution, filter, and obtain sodium metavanadate solution.

[0071] In step (ii), some soluble impurities or impurities soluble in alkaline sodium hydroxide solution are removed to improve the purity of sodium metavanadate solution.

[0072] (iii) Heat the sodium metavanadate solution obtained in step (ii) to 70°C, add the chloromethyl polystyrene resin loaded with ozone and graphene oxide prepared in step (i), stir and react for 60 minutes, filter, and take the filtrate.

[0073] Furthermore, in step (iii), the amount of oxidant added is sufficient to allow the low-valent vanadium, such as trivalent and tetravalent vanadium, in the sodium metavanadate solution to fully react and generate pentavalent vanadium. In this embodiment, the amount of oxidant added is equivalent to 0.2% of the weight of the crude ammonium metavanadate in step (ii).

[0074] Studies have shown that ozone and graphene oxide can oxidize low-valent vanadium in sodium metavanadate solution to high-valent vanadium, improving the yield and recovery rate of vanadium and increasing the purity of vanadium pentoxide. Excessively high temperatures cause ozone to evaporate too quickly, hindering its oxidation of low-valent vanadium; conversely, excessively low temperatures result in a slow oxidation rate by both ozone and graphene oxide, also impeding complete oxidation of vanadium.

[0075] (iv) Add ammonium metavanadate crystals to the filtrate obtained in step (iii) for recrystallization to obtain ammonium metavanadate precipitate. Separate the solid and liquid and dry it to obtain ammonium metavanadate crystals.

[0076] (v) Calcining the ammonium metavanadate crystals obtained in step (iv) yields vanadium pentoxide.

[0077] Studies have shown that graphene oxide and ozone, after loading treatment, exhibit excellent oxidation performance. The combination of graphene oxide and ozone can rapidly oxidize low-valent vanadium, such as trivalent or tetravalent vanadium, in ammonium metavanadate solution to pentavalent vanadium, improving reaction activity and forming a stable structure to obtain the target product, thus increasing the purity of the final product, vanadium pentoxide. Chloromethyl polystyrene resin can be removed during recrystallization, and the gas generated after the ozone reaction is easily separated; graphene oxide can be separated by filtration. Without the loading of ozone and graphene oxide, it exhibits oxidative inertness and cannot fully exert its oxidation performance. This may be because ozone is easily decomposed and volatilized, while graphene oxide remains unactivated, resulting in relatively stable performance. This invention, using a loading method, not only solves the problem of easy ozone decomposition and volatilization but also addresses the issue of graphene oxide failing to react under certain conditions due to inactivation.

[0078] The vanadium pentoxide produced by this invention has high purity and few impurities, which fully meets the production requirements of some high-end products.

[0079] The purity of vanadium pentoxide obtained by this invention is 99.990%, wherein the sum of the contents of tetravalent vanadium and trivalent vanadium is 0.002%.

[0080] Comparative Example 1

[0081] Except for step (i), in which the oxidant is prepared by a simple mixture of graphene oxide, chloromethyl polystyrene resin, and ozone instead of a loaded method, the other operations and parameters in this comparative example are the same as in Example 1.

[0082] The purity of vanadium pentoxide obtained in this comparative example is 98.20%, with a combined content of tetravalent and trivalent vanadium of 0.5%. It is evident that without using a supported method to prepare the oxidant, the content of tetravalent and trivalent vanadium remains high, failing to achieve the intended purpose of the invention.

[0083] Comparative Example 2

[0084] Except for step (3) where ozone gas is not introduced, the operation and parameters of this comparative example are the same as those of Example 1.

[0085] The purity of vanadium pentoxide obtained in this comparative example is 98.80%, with a combined content of tetravalent and trivalent vanadium of 0.4%. It is evident that without introducing ozone to prepare the oxidant, simply using supported graphene oxide cannot achieve the intended purpose of the invention.

[0086] Comparative Example 3

[0087] Except for step (iii) where no oxidant is added to the chloromethyl polystyrene resin loaded with ozone and graphene oxide, and only ozone is introduced, the other operations and parameters of this comparative example are the same as those of Example 1.

[0088] The purity of vanadium pentoxide obtained in this comparative example is 98.30%, with a combined content of tetravalent and trivalent vanadium of 0.5%. It is evident that simply introducing ozone has limited effect on the oxidation of low-valent vanadium and fails to achieve the objective of this invention.

Claims

1. A method for preparing vanadium pentoxide using ammonium metavanadate, characterized in that, Includes the following steps: (a) Preparation of oxidizing agents: (1) Add graphene oxide to chloromethyl polystyrene resin, and use ultrasonic dispersion and magnetic stirring for 20-150 min to make it fully dispersed and uniform, so as to obtain a mixture; (2) Adjust the pH of the mixture obtained in step (1) to 8-9; (3) Transfer the mixture whose pH value has been adjusted in step (2) to a high-pressure container, introduce ozone gas into the mixture, and keep it at a pressure of 500-800 kPa for 10-36 hours to obtain an oxidant, wherein the oxidant is a chloromethyl polystyrene resin loaded with ozone and graphene oxide. (ii) Dissolve crude ammonium metavanadate in water by heating. After dissolving, adjust the pH value to 8-9 with sodium hydroxide solution, filter, and obtain sodium metavanadate solution. (iii) Heat the sodium metavanadate solution obtained in step (ii) to 60-80℃, add the chloromethyl polystyrene resin loaded with ozone and graphene oxide prepared in step (i), stir and react for more than 20 minutes, filter, and take the filtrate. In step (iii), the amount of oxidant added is sufficient to allow the trivalent and tetravalent vanadium in the sodium metavanadate solution to fully react and generate pentavalent vanadium; the amount of oxidant added is equivalent to 0.1-10% of the weight of the crude ammonium metavanadate in step (ii). (iv) Add ammonium metavanadate crystals to the filtrate obtained in step (iii) for recrystallization to obtain ammonium metavanadate precipitate. Separate the solid and liquid and dry it to obtain ammonium metavanadate crystals. (v) Calcining the ammonium metavanadate crystals obtained in step (iv) yields vanadium pentoxide.

2. The method for preparing vanadium pentoxide using ammonium metavanadate according to claim 1, characterized in that, In step (1), the ultrasonic dispersion and magnetic stirring time is 30-60 minutes.

3. The method for preparing vanadium pentoxide from ammonium metavanadate according to claim 1 or 2, characterized in that, In step (1), the mass ratio of graphene oxide to chloromethyl polystyrene resin is 1-5:

1.

4. The method for preparing vanadium pentoxide from ammonium metavanadate according to claim 1 or 2, characterized in that, In step (1), the frequency of ultrasonic dispersion is 1.6 to 1.8 kHz.

5. The method for preparing vanadium pentoxide from ammonium metavanadate according to claim 1 or 2, characterized in that, In step (2), the pH is adjusted using sodium hydroxide or ammonia.

6. The method for preparing vanadium pentoxide from ammonium metavanadate according to claim 1 or 2, characterized in that, In step (3), stir the reaction for 30-60 minutes.

7. The method for preparing vanadium pentoxide from ammonium metavanadate according to claim 1 or 2, characterized in that, In step (iii), the amount of oxidant added is 1-5% of the weight of crude ammonium metavanadate in step (ii).