Recovery method of waste vanadium battery electrolyte

Abstract

The invention discloses a recovery method of a waste vanadium battery electrolyte, and relates to the technical field of electrolytes. A recovery method of a waste vanadium battery electrolyte comprises the following steps: electro-deposition: filtering the vanadium battery electrolyte containing impurities to obtain a filtrate, and then carrying out electro-deposition treatment on the filtrate to obtain a first material; valence state regulation: adding an oxidizing agent into the first material and stirring for reaction to obtain a second material; vanadium precipitation: adjusting the pH value of the second material, then adding a vanadium precipitation agent, and stirring for reaction to obtain a third material; and calcining: filtering the third material to obtain filter residues, and calcining the filter residues to obtain a vanadium product. According to the method, various impurities contained in the vanadium battery electrolyte can be effectively removed, recycling of the waste electrolyte is achieved, and secondary pollution of waste can be effectively avoided; the method is simple in process, convenient to operate, mild in condition, wide in adaptability, extremely high in economic benefit and beneficial to large-scale popularization and application.

Description

Technical Field

[0001] The present application relates to the technical field of electrolytes, and in particular to a method for recovering waste vanadium battery electrolytes. Background Art

[0002] All-vanadium flow batteries have gradually become one of the preferred technologies for energy storage systems due to their long life, high safety and large-scale energy storage capacity. However, in the actual operation of vanadium batteries, the electrolyte is easily affected by external factors, such as electrolyte leakage and corrosion, which lead to the introduction of various metal impurities (such as copper, iron, calcium, sodium, etc.). Severe excess of these impurities will significantly affect the electrochemical stability of the battery, making it lose the ability to continue to be used, thereby reducing the performance and service life of the battery.

[0003] Most existing electrolyte recovery technologies rely on a single step or simple chemical precipitation methods. These methods lack systematicity and flexibility, and are difficult to effectively deal with different types and impurity contents of waste vanadium battery electrolytes, resulting in waste of resources, low recovery rates, and even secondary pollution. In addition, since waste vanadium battery electrolytes contain a large amount of high-value vanadium resources, if they are directly discarded, it will not only waste resources, but also have serious negative impacts on the environment. Existing recovery and processing processes are usually costly and complex to operate, making them difficult to promote in large-scale industrial applications. Summary of the invention

[0004] The purpose of the present application is to provide a method for recycling waste vanadium battery electrolyte, which can effectively remove various impurities contained in the vanadium battery electrolyte, realize the recycling of the waste electrolyte, effectively avoid secondary pollution of waste, and realize a green and sustainable production process; the method has a simple process, convenient operation, mild conditions, wide adaptability, extremely high economic benefits, and is conducive to large-scale promotion and application.

[0005] The technical solution of this application is as follows:

[0006] The present application provides a method for recycling waste vanadium battery electrolyte, which comprises the following steps:

[0007] Electrodeposition: filtering the vanadium battery electrolyte containing impurities to remove large particle impurities and suspended matter to obtain a filtrate, and then subjecting the filtrate to an electro-deposition treatment to separate and remove metal impurities to obtain a first material;

[0008] Valence state adjustment: adding an oxidant to the first material and stirring to react to obtain a second material;

[0009] Vanadium precipitation: adjust the pH of the second material, then add the vanadium precipitation agent, and stir the reaction to obtain the third material;

[0010] Calcination: filtering the third material to obtain filter residue, and then calcining the filter residue to obtain a vanadium product.

[0011] Furthermore, in some embodiments of the present application, in the above-mentioned electrodeposition step, a filter membrane with a pore size of 0.1 to 20 μm is used to filter the electrolyte at a temperature of 20 to 60° C., and the filtration rate is 1 to 20 L / h.

[0012] Furthermore, in some embodiments of the present application, in the above-mentioned electrodeposition step, the temperature is 15 to 80° C. and the current density is 10 to 200 mA / cm 2 The filtrate was electrodeposited under the conditions of .

[0013] Furthermore, in some embodiments of the present application, in the above-mentioned electrodeposition step, the electrodeposition duration is 0.5 to 100 hours.

[0014] Furthermore, in some embodiments of the present application, in the above-mentioned valence state adjustment step, the oxidant used is any one or more of oxidants such as potassium permanganate, hydrogen peroxide, ozone, sodium hypochlorite, etc.

[0015] Furthermore, in some embodiments of the present application, in the above-mentioned valence state adjustment step, the concentration of the oxidant used should be greater than 0.05 mol / L, and the reaction temperature should be 20-60°C.

[0016] Furthermore, in some embodiments of the present application, in the above valence state adjustment step, during the stirring reaction, the stirring rate is 100 to 400 rpm, and the reaction time is 1 to 4 hours.

[0017] Furthermore, in some embodiments of the present application, in the above vanadium precipitation step, the pH of the second material is adjusted to 3.0-10.0, and then the vanadium precipitating agent is added.

[0018] Furthermore, in some embodiments of the present application, in the above-mentioned vanadium precipitation step, an acid or a base is added to the second material to adjust the pH; wherein the acid is any one or more of sulfuric acid, hydrochloric acid, nitric acid, acetic acid and the like, and the base is any one or more of sodium hydroxide, potassium hydroxide, ammonia water and the like.

[0019] Furthermore, in some embodiments of the present application, in the above vanadium precipitation step, the pH of the second material is adjusted at 20-50°C.

[0020] Furthermore, in some embodiments of the present application, in the above-mentioned vanadium precipitation step, the vanadium precipitation agent used is any one or more of calcium chloride, aluminum sulfate, calcium phosphate, and aluminum nitrate.

[0021] Furthermore, in some embodiments of the present application, in the above vanadium precipitation step, the amount of vanadium precipitation agent added to the system is 0.01-0.5 mol / L, and the reaction temperature is 20-80°C.

[0022] Furthermore, in some embodiments of the present application, in the above vanadium precipitation step, when stirring the reaction, the stirring rate is 100 to 600 rpm and the reaction time is 1 to 4 hours.

[0023] Furthermore, in some embodiments of the present application, in the above calcination step, a filter membrane with a pore size of 0.1 to 20 μm is used to filter the electrolyte at a temperature of 20 to 60° C., and the filtration rate is 1 to 20 L / h.

[0024] Furthermore, in some embodiments of the present application, in the above calcination step, the calcination is carried out at a temperature of 400 to 800° C. and the calcination time is 1 to 8 hours to obtain a vanadium product.

[0025] Furthermore, in some embodiments of the present application, in the above calcination step, the vanadium product obtained is pure vanadium oxide or other vanadium compounds that can be reused.

[0026] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0027] In view of the above aspects, the embodiments of the present application provide a method for recovering waste vanadium battery electrolyte, which first filters the vanadium battery electrolyte containing multiple impurities to remove large particle impurities and suspended matter contained therein, so as to prevent unexpected situations such as blockage in subsequent steps, and provide relatively pure basic materials for subsequent steps to avoid adverse effects on processing efficiency. The filtrate obtained by filtration is then subjected to electroplating treatment, so that metal impurities such as copper, iron, and zinc contained therein are deposited and separated on the cathode of the electroplating system; during the process, the current density, temperature, and time parameters can be adjusted according to different types of electrolytes to meet the requirements of impurity removal. After the electrodeposition is completed, a first material is obtained, and then the valence state of the first material is adjusted: an oxidant (such as potassium permanganate, hydrogen peroxide, ozone, sodium hypochlorite, etc.) is added to the first material to reduce the low-valent vanadium ions (such as V 2+ 、V 3+ ) is oxidized to high-valent vanadium ions (such as V 4+ 、V 5+) to maintain the chemical stability of the electrolyte to obtain the second material. The pH of the second material is adjusted by adding alkali or acid to achieve the appropriate conditions for the subsequent vanadium precipitation step to ensure the effect of the subsequent vanadium precipitation operation; then the vanadium precipitation step is performed: a vanadium precipitation agent is added to the second material after the pH is adjusted to perform vanadium precipitation treatment, so that the vanadium is precipitated in the form of an insoluble vanadium compound to obtain a third material. Finally, the obtained third material is filtered to separate the solid vanadium compound precipitate generated during the vanadium precipitation process to ensure the complete removal of impurities, and then the filter residue is calcined to decompose or oxidize it to obtain a reusable vanadium product; during the calcination process, the calcination temperature and time can be adjusted according to the specific chemical composition of the vanadium precipitation product and the target product requirements. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0029] It should be noted that relational terms such as "first", "second", "third", etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises..." do not exclude the existence of other identical elements in the process, method, article or device including its elements.

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0031] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0032] Example 1

[0033] The present application provides a method for recycling waste vanadium battery electrolyte, which comprises the following steps:

[0034] Electrodeposition: Use a filter membrane with a pore size of 0.1 to 20 μm to filter the vanadium battery electrolyte containing impurities at a temperature of 20 to 60°C at a filtering speed of 1 to 20 L / h to remove large particles of impurities and suspended matter to obtain a filtrate;

[0035] Then at a temperature of 15-80°C and a current density of 10-200 mA / cm 2 Electrodepositing the filtrate under the conditions of , the duration of the electrodeposition is 0.5 to 100 hours, to obtain a first material;

[0036] Valence state adjustment: adding an oxidant to the first material and stirring to react to obtain a second material;

[0037] The oxidant is any one or more of potassium permanganate, hydrogen peroxide, ozone, sodium hypochlorite and the like, and the concentration of the oxidant is 0.05 to 1 mol / L; during the stirring reaction, the reaction temperature is 20 to 60° C., the stirring rate is 100 to 400 rpm, and the reaction time is 1 to 4 hours;

[0038] Vanadium precipitation: at 20-50°C, use acid or alkali to adjust the pH of the second material to 3.0-10.0; then add the vanadium precipitation agent, stir and react to obtain the third material;

[0039] The acid used is any one or more of sulfuric acid, hydrochloric acid, nitric acid, acetic acid and the like, and the base is any one or more of sodium hydroxide, potassium hydroxide, ammonia and the like; the vanadium precipitator used is any one or more of calcium chloride, aluminum sulfate, calcium phosphate, aluminum nitrate, and the amount of the vanadium precipitator added to the system is 0.01-0.5 mol / L; when stirring the reaction, the reaction temperature is 20-80°C, the stirring rate is 100-600 rpm, and the reaction time is 1-4 hours;

[0040] Calcination: using a filter membrane with a pore size of 0.1 to 20 μm, filtering the third material at a temperature of 20 to 60° C. at a filtering speed of 1 to 20 L / h to obtain a filter residue;

[0041] Then, the filter residue is calcined at a temperature of 400 to 800° C. for 1 to 8 hours to obtain pure vanadium oxide or other vanadium compounds that can be reused.

[0042] Based on the method of this embodiment, the relevant process condition parameters in the above steps can be adjusted according to different electrolyte types and contamination levels to achieve an optimized treatment effect.

[0043] Example 2

[0044] This embodiment is based on Embodiment 1 and is a specific application of the method of Embodiment 1, and includes the following steps:

[0045] Electrodeposition: Use a filter membrane with a pore size of 0.22 μm to filter the vanadium battery electrolyte containing impurities at a temperature of 20°C to remove large particle impurities and suspended matter to obtain a filtrate;

[0046] Then at a temperature of 30°C and a current density of 100 mA / cm 2 Electrodeposition was performed on the filtrate under the conditions of , and the duration of the electrodeposition was 6 hours to obtain a first material;

[0047] Valence adjustment: adding potassium permanganate, an oxidant, at a concentration of 0.3 mol / L to the first material and stirring to react to obtain a second material;

[0048] Wherein, during the stirring reaction, the reaction temperature is 25°C and the reaction time is 1h;

[0049] Vanadium precipitation: at 20-50°C, use acid or alkali to adjust the pH of the second material to 6.0; then add vanadium precipitation agent calcium chloride, stir and react to obtain the third material;

[0050] The amount of vanadium precipitation agent added to the system was 0.1 mol / L; during the stirring reaction, the reaction temperature was 50°C and the reaction time was 3h;

[0051] Calcination: The third material is filtered to obtain filter residue; the filter residue is then calcined at a temperature of 600° C. for 3 hours to obtain a pure vanadium product.

[0052] In this embodiment, the final vanadium recovery rate is 96.5%.

[0053] Example 3

[0054] This embodiment is based on Embodiment 1 and is a specific application of the method of Embodiment 1, and includes the following steps:

[0055] Electrodeposition: Use a filter membrane with a pore size of 0.45 μm to filter the vanadium battery electrolyte containing impurities at a temperature of 20°C to remove large particle impurities and suspended matter, and then filter it again with a 0.22 μm filter membrane to remove residual particle impurities and suspended matter to obtain a filtrate;

[0056] Then at a temperature of 20°C and a current density of 100 mA / cm 2 Electrodeposition was performed on the filtrate under the conditions of , and the duration of the electrodeposition was 6 hours to obtain a first material;

[0057] Valence state adjustment: adding solid oxidant potassium permanganate to the first material and stirring to react to obtain a second material;

[0058] Wherein, during the stirring reaction, the reaction temperature is 25°C and the reaction time is 1h;

[0059] Vanadium precipitation: at 20-50°C, use acid or alkali to adjust the pH of the second material to 5.9; then add vanadium precipitation agent calcium chloride, stir and react to obtain the third material;

[0060] The amount of vanadium precipitation agent added to the system was 0.1 mol / L; during the stirring reaction, the reaction temperature was 50°C and the reaction time was 3h;

[0061] Calcination: The third material is filtered to obtain filter residue; the filter residue is then calcined at a temperature of 540° C. for 3 hours to obtain a pure vanadium product.

[0062] In this embodiment, the final vanadium recovery rate is 96.3%.

[0063] Example 4

[0064] This embodiment is based on Embodiment 1 and is a specific application of the method of Embodiment 1, and includes the following steps:

[0065] Electrodeposition: Use a filter membrane with a pore size of 0.1 μm to filter the vanadium battery electrolyte containing impurities at a temperature of 20°C to remove large particle impurities and suspended matter to obtain a filtrate, and then use a 0.22 μm filter membrane for secondary filtration to remove residual particle impurities and suspended matter to obtain a filtrate;

[0066] Then at a temperature of 28°C and a current density of 100 mA / cm 2 Electrodeposition was performed on the filtrate under the conditions of , and the duration of the electrodeposition was 6 hours to obtain a first material;

[0067] Valence state adjustment: adding solid oxidant sodium hypochlorite to the first material and stirring to react to obtain a second material;

[0068] Wherein, during the stirring reaction, the reaction temperature is 25°C and the reaction time is 1h;

[0069] Vanadium precipitation: at 20-50°C, use acid or alkali to adjust the pH of the second material to 6.1; then add vanadium precipitation agent calcium chloride, stir and react to obtain the third material;

[0070] The amount of vanadium precipitation agent added to the system was 0.1 mol / L; during the stirring reaction, the reaction temperature was 50°C and the reaction time was 3h;

[0071] Calcination: The third material is filtered to obtain filter residue; the filter residue is then calcined at a temperature of 550° C. for 3 hours to obtain a pure vanadium product.

[0072] In this embodiment, the final vanadium recovery rate is 96.1%.

[0073] Example 5

[0074] This embodiment is based on Embodiment 1 and is a specific application of the method of Embodiment 1, and includes the following steps:

[0075] Electrodeposition: After adding a small amount of activated carbon and stirring for 1 hour, use a filter bag with a pore size of 0.45μm to filter the vanadium battery electrolyte containing impurities at a temperature of 20°C to remove large particle impurities and suspended matter. After obtaining the filtrate, use a 0.22μm filter membrane for secondary filtration to remove residual particle impurities and suspended matter to obtain a filtrate;

[0076] Then at a temperature of 20°C and a current density of 100 mA / cm 2 Electrodeposition was performed on the filtrate under the conditions of , and the duration of the electrodeposition was 6 hours to obtain a first material;

[0077] Valence state adjustment: adding hydrogen peroxide accounting for 30% by weight of the oxidant to the first material and stirring to react to obtain the second material;

[0078] Wherein, during the stirring reaction, the reaction temperature is 25°C and the reaction time is 1h;

[0079] Vanadium precipitation: at 20-50°C, use acid or alkali to adjust the pH of the second material to 6.5; then add vanadium precipitation agent aluminum phosphate, stir and react to obtain the third material;

[0080] The amount of vanadium precipitation agent added to the system was 0.1 mol / L; during the stirring reaction, the reaction temperature was 50°C and the reaction time was 3h;

[0081] Calcination: The third material is filtered to obtain filter residue; the filter residue is then calcined at a temperature of 600° C. for 3 hours to obtain a pure vanadium product.

[0082] In this embodiment, the final vanadium recovery rate is 96%.

[0083] Example 6

[0084] This embodiment is based on Embodiment 1 and is a specific application of the method of Embodiment 1, and includes the following steps:

[0085] Electrodeposition: Use a filter membrane with a pore size of 0.45 μm to filter the vanadium battery electrolyte containing impurities at a temperature of 20°C to remove large particle impurities and suspended matter. After obtaining the filtrate, add a small amount of fruit shell activated carbon and stir for 1 hour. Then, use a 0.22 μm filter membrane for secondary filtration to remove residual particle impurities and suspended matter to obtain a filtrate;

[0086] Then at room temperature 28°C, the current density was 100 mA / cm 2Electrodeposition was performed on the filtrate under the conditions of , and the duration of the electrodeposition was 6 hours to obtain a first material;

[0087] Valence state adjustment: adding solid oxidant sodium hypochlorite to the first material and stirring to react to obtain a second material;

[0088] Wherein, during the stirring reaction, the reaction temperature is 25°C and the reaction time is 1h;

[0089] Vanadium precipitation: at 20-50°C, use acid or alkali to adjust the pH of the second material to 6.1; then add vanadium precipitation agent calcium chloride, stir and react to obtain the third material;

[0090] The amount of vanadium precipitation agent added to the system was 0.05 mol / L; during the stirring reaction, the reaction temperature was 50°C and the reaction time was 3 h;

[0091] Calcination: The third material is filtered to obtain filter residue; the filter residue is then calcined at a temperature of 550° C. for 3 hours to obtain a pure vanadium product.

[0092] In this embodiment, the final vanadium recovery rate is 96.6%.

[0093] In summary, the embodiment of the present application provides a method for recycling waste vanadium battery electrolyte, which can systematically remove large particle impurities, metal impurities, particulate matter and low-valent vanadium ions in the electrolyte. Compared with the prior art, the multi-step process adopted in the present application scheme can more comprehensively process waste vanadium battery electrolytes of different types and contamination levels, significantly improving the recovery rate and purity of vanadium.

[0094] In its process steps, metal impurities (such as copper, iron, zinc, etc.) are deposited and separated on the cathode by electrodeposition, and the removal requirements of metal impurities in different types of electrolytes can be adapted by adjusting the current density, temperature and time parameters. This is an important technical point for achieving high-purity vanadium recovery. Compared with the single step or simplified treatment method in the prior art, the electrodeposition process of the present application is more targeted and efficient, and significantly improves the removal effect of metal impurities.

[0095] In addition, the present invention adjusts the valence state of vanadium ions by adding an oxidant to the electrolyte, so that low-valent vanadium ions (such as V 2+ 、V 3+ ) into high-valent vanadium ions (such as V 4+ 、V 5+ ), the setting of this step ensures the chemical stability of the electrolyte and is the key operation to maintain the performance of the vanadium battery; this diversified selection of oxidants and the optimized configuration of their concentrations and reaction conditions enhance the adaptability and stability of the present invention, especially for waste liquids with different degrees of pollution.

[0096] In the present application, the pH of the material is first adjusted during vanadium precipitation to ensure the effectiveness of the subsequent vanadium precipitation operation; the flexibility and adaptability of the vanadium precipitation step of the present application is one of the core advantages of the present invention, and it can be customized according to the specific impurity conditions in the electrolyte and the characteristics of the vanadium compound, which significantly improves the vanadium precipitation efficiency and recovery effect; by adding a vanadium precipitation agent to the electrolyte and controlling the reaction conditions, vanadium can be effectively precipitated in the form of an insoluble vanadium compound.

[0097] Finally, it is decomposed or oxidized by calcination to form pure vanadium oxide (such as V 2 O 5 ) or other vanadium compounds. The calcination temperature and time can be optimized and adjusted according to the specific chemical composition of the vanadium precipitation product and the target product requirements, which is a key step in achieving resource recycling.

[0098] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. A method for recovering waste vanadium battery electrolyte, characterized in that: It includes the following steps: Electrodeposition: filtering the vanadium battery electrolyte containing impurities to remove large particle impurities and suspended matter to obtain a filtrate, and then subjecting the filtrate to an electro-deposition treatment to separate and remove metal impurities to obtain a first material; Valence state adjustment: adding an oxidant to the first material and stirring to react to obtain a second material; Vanadium precipitation: adjust the pH of the second material, then add the vanadium precipitation agent, and stir the reaction to obtain the third material; Calcination: filtering the third material to obtain filter residue, and then calcining the filter residue to obtain a vanadium product.

2. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the electrodeposition step, the temperature is 15-80°C and the current density is 10-200 mA / cm 2 The filtrate was electrodeposited under the conditions of .

3. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the valence state adjustment step, the oxidant used is any one or more of oxidants such as potassium permanganate, hydrogen peroxide, ozone, sodium hypochlorite, etc.

4. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the valence state adjustment step, the concentration of the oxidant used should be equal to or greater than 0.05 mol / L, and the reaction temperature should be 20-60°C.

5. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the vanadium precipitation step, the pH of the second material is adjusted to 3.0-10.0, and then a vanadium precipitating agent is added.

6. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the vanadium precipitation step, the vanadium precipitation agent used is any one or more of calcium chloride, aluminum sulfate, calcium phosphate, and aluminum nitrate.

7. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the vanadium precipitation step, the amount of vanadium precipitation agent added to the system is 0.01-0.5 mol / L, and the reaction temperature is 20-80°C.

8. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the calcination step, calcination is carried out at a temperature of 400 to 800° C. to obtain a vanadium product.

9. The method for recovering waste vanadium battery electrolyte according to claim 1, characterized in that: In the calcination step, the vanadium product obtained is pure vanadium oxide or other vanadium compounds that can be reused.