Method and system for continuously producing electrolyte from ammonium metavanadate

Abstract

The present disclosure provides a method and system for continuously producing an electrolyte from ammonium metavanadate. The method provided by the present disclosure comprises: (1) reducing an ammonium metavanadate material at predetermined pressure and a predetermined temperature, and controlling the circulation amount of a gas generated by reduction and the feeding speed of the material to obtain a product containing vanadium oxide, wherein the predetermined pressure is 0.02-0.12 MPa, and the predetermined temperature is 400-650°C; and (2) when the temperature of the product containing vanadium oxide is reduced to a predetermined threshold, feeding acid and water, controlling the feeding speed of the acid and the water, and performing continuous production to obtain the electrolyte in a target valence state, wherein the electrolyte in the target valence state is a 3-4 valent vanadium electrolyte. Ammonium metavanadate is reduced, and vanadium oxides in different valence states are obtained by controlling the circulation amount of the gas generated by reduction and the feeding speed of ammonium metavanadate. Moreover, the acid and the water are fed, and continuous production is performed to obtain the vanadium electrolyte in the target valence state.

Description

A method and system for continuously producing electrolyte using ammonium metavanadate

[0001] This application claims priority to Chinese patent application No. 202311744874.3 filed in China on December 19, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the technical field of vanadium product preparation, and in particular to a method and system for continuously producing electrolyte using ammonium metavanadate. Background Art

[0003] Electrolyte is an important component of all-vanadium flow batteries and plays a decisive role in the overall performance of vanadium batteries. Currently, the main preparation methods of vanadium redox flow electrolytes include physical dissolution, reduction, electrolysis, and chemical-electrolysis. Among them, the reduction method is often used to prepare 3.5-valent vanadium electrolyte. Chinese patent application CN116995285A discloses a short-process method for preparing 3.5-valent vanadium oxysulfate electrolyte, comprising the following steps: (1) ammonium metavanadate and / or ammonium polyvanadate are reduced and calcined with a reducing gas to obtain vanadium oxide; (2) mixed sulfuric acid solution and vanadium oxide are subjected to a dissolution reaction and vanadium adjustment to obtain 3.5-valent vanadium oxysulfate electrolyte. This method avoids the long process of obtaining high-purity vanadium pentoxide after calcining ammonium vanadate and then preparing 3.5-valent vanadium oxysulfate electrolyte by chemical reduction-electrochemical reduction, simplifies the process, reduces production costs, and optimizes the production process of 3.5-valent vanadium oxysulfate electrolyte.

[0004] The reduction process for preparing 3.5-valent vanadium electrolyte requires the addition of a reducing agent, such as hydrogen. However, the utilization rate of this reducing agent is low, typically around 30%, resulting in significant material consumption. Furthermore, the water produced during the reduction process causes the reducing material to become severely lumpy, making subsequent dissolution difficult and energy-intensive. Furthermore, the high-temperature reduction process for the vanadium raw material lasts for a long time, and the heat from the cooling process is difficult to effectively utilize.

[0005] The method for preparing 3-4 valent vanadium electrolyte needs further improvement. Summary of the Invention

[0006] The present disclosure aims to solve, at least to a certain extent, one of the technical problems in the related art. It is difficult to achieve a valence of less than 4, especially 3.5, by reducing ammonium metavanadate. The present disclosure provides a method and system for the continuous production of electrolyte using ammonium metavanadate. The method provided by the present disclosure improves the utilization rate of ammonium in the reduction process by controlling the pressure and temperature and the gas emptying rate during the reduction process, thereby ensuring that the reduction reaches the required valence state. By controlling the cooling temperature of the reducing raw materials, the efficiency and energy efficiency of the dissolution process are ensured. By utilizing the waste heat from material cooling, energy losses are reduced.

[0007] Specifically, the present disclosure provides the following technical solutions:

[0008] In a first aspect of the present disclosure, a method for continuously producing an electrolyte using ammonium metavanadate is provided, comprising:

[0009] (1) reducing an ammonium metavanadate material at a predetermined pressure and a predetermined temperature, and obtaining a vanadium oxide-containing product by controlling the circulation rate of the gas generated by the reduction and the feed rate of the material, wherein the predetermined pressure is 0.02 to 0.12 MPa and the predetermined temperature is 400 to 650 degrees Celsius;

[0010] (2) When the temperature of the vanadium oxide-containing product drops to a predetermined threshold, acid and water are added, and by controlling the flow acceleration of the acid and water, the target valence electrolyte is continuously produced, wherein the target valence electrolyte is a 3-4 valence vanadium electrolyte.

[0011] The method provided by the present disclosure enables the ammonium metavanadate material to be reduced by controlling suitable pressure and temperature, and the utilization rate of ammonium in the reduction process is improved by controlling the circulation amount of the gas produced by the reduction and the feeding rate of ammonium metavanadate, and vanadium oxides of different valences are obtained. At the same time, acid and water are added, and the flow acceleration of the acid and water is controlled to the temperature of the vanadium oxide, and the vanadium electrolyte of the target valence state is obtained by continuous production, for example, any desired 3-4 valence vanadium electrolyte can be obtained, such as 3 valence, 3.1 valence, 3.2 valence, 3.3 valence, 3.4 valence, 3.5 valence, 3.6 valence, 3.7 valence, 3.8 valence, 3.9 valence, and 4 valence vanadium electrolytes.

[0012] According to an embodiment of the present disclosure, the above-mentioned method for continuously producing electrolyte from ammonium metavanadate may further include the following technical features:

[0013] In some embodiments of the present disclosure, the reduction time in step (1) is 1.5 to 4 hours.

[0014] In some embodiments of the present disclosure, the gas generated by the reduction in step (1) includes nitrogen, hydrogen and / or ammonia, and the circulation amount of nitrogen, hydrogen and / or ammonia is controlled by the inlet valve and the outlet valve.

[0015] In some embodiments of the present disclosure, the reduction in step (1) is performed in a reduction furnace, and the stacking ratio of the material in the reduction furnace is 12-18%.

[0016] In some embodiments of the present disclosure, the acid in step (2) is sulfuric acid. In some embodiments of the present disclosure, the flow acceleration of the acid is based on the flow rate per 1L of water, corresponding to the flow addition of 300g to 800g of acid per minute; the flow acceleration of the water is based on the flow rate per 1g of material, corresponding to the flow addition of 2 to 5mL of water per minute. By controlling the speed of adding acid and water, it is possible to ensure that the heat preservation reaction is achieved. This can achieve the dissolution process without heating, solve the problem of high energy consumption, and reduce energy consumption.

[0017] In some embodiments of the present disclosure, the predetermined threshold in step (2) is 60-110 degrees Celsius, and the temperature of the vanadium oxide-containing product is controlled to drop to the predetermined threshold by an external cooling water pipe. For example, the predetermined threshold may be 60-100 degrees Celsius.

[0018] In some embodiments of the present disclosure, water flowing through the external cooling water pipeline is added to step (2) as supplementary water.

[0019] A second aspect of the present disclosure provides a system for continuously producing an electrolyte using ammonium metavanadate, comprising:

[0020] A reduction unit, wherein the reduction unit uses an ammonium metavanadate material to reduce a product containing vanadium oxide in a reduction furnace at a predetermined pressure and a predetermined temperature to obtain a product containing vanadium oxide. The reduction furnace is equipped with an inlet valve and an outlet valve, and the inlet valve and the outlet valve are used to regulate the circulation volume of the gas generated by the reduction. The reduction furnace is equipped with a feed port and a discharge port, the feed port controls the feed rate of the material, and the discharge port controls the outflow of the product. The predetermined pressure is 0.02-0.12 MPa, and the predetermined temperature is 400-650 degrees Celsius.

[0021] An acid addition unit is used to add acid and water when the vanadium oxide-containing product drops to a predetermined threshold value, and by controlling the flow acceleration of the acid and water, continuously produce an electrolyte with a target valence state in a reaction tank, wherein the electrolyte with a target valence state is a 3-4 valence vanadium electrolyte; the acid addition unit is connected to the discharge port of the reduction furnace, and the reaction tank is connected to the acid feed port and the water feed port.

[0022] In some embodiments of the present disclosure, the gas generated by the reduction includes nitrogen, hydrogen and / or ammonia, and the circulation amount of nitrogen, hydrogen and / or ammonia is controlled by an inlet valve and an outlet valve.

[0023] In some embodiments of the present disclosure, the flow acceleration of the acid feed port is based on the flow rate per 1L of water, corresponding to the flow rate of 300g to 800g of acid per minute;

[0024] The flow acceleration of the water feed port is calculated as 2-5 mL of water per minute for every 1 g of material.

[0025] In some embodiments of the present disclosure, the reduction furnace is externally connected to a cooling water pipe, which controls the temperature of the vanadium oxide-containing product to drop to a predetermined threshold, and the cooling water pipe is connected to the water feed port.

[0026] The beneficial effects achieved by this disclosure are:

[0027] (1) The method provided by the present disclosure improves the utilization rate of ammonium during the reduction process by controlling the pressure, temperature, and gas exhaust rate during the reduction process, thereby ensuring that the reduction reaches the desired valence state.

[0028] (2) By controlling the cooling temperature of the reducing materials, for example, adding acid and water at 60-110 degrees Celsius, the energy consumption is very low, ensuring the efficiency of the dissolution process and energy efficiency.

[0029] (3) By utilizing the waste heat from material cooling, energy loss is reduced; and by continuously adding and removing materials, the materials will not become compacted, which will not cause the problem of difficulty in dissolving the subsequent reduction products. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a flow chart of a method for continuously producing an electrolyte using ammonium metavanadate according to an embodiment of the present disclosure.

[0031] Figure 2 is a structural schematic diagram of a system for continuous production of electrolyte by ammonium metavanadate provided by an embodiment of the present disclosure, wherein reference numeral 100 is a reduction furnace, 101 is an air inlet valve, 102 is an air outlet valve, 103 is a feed port, and 104 is a discharge port; 200 is a reaction tank, 201 is an acid feed port, and 202 is a water feed port. DETAILED DESCRIPTION

[0032] Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0033] The present disclosure provides a method for continuously producing an electrolyte using ammonium metavanadate, as shown in FIG1 , comprising: S100: reducing an ammonium metavanadate material at a predetermined pressure and a predetermined temperature, and S200: continuously producing an electrolyte having a target valence state using a product containing vanadium oxide, acid, and water.

[0034] The method for continuously producing an electrolyte from ammonium metavanadate provided in the present disclosure includes:

[0035] (1) reducing ammonium metavanadate at a predetermined pressure and a predetermined temperature, and obtaining a vanadium oxide-containing product by controlling the circulation rate of the gas generated by the reduction and the feed rate of the material, wherein the predetermined pressure is 0.02 to 0.12 MPa and the predetermined temperature is 400 to 650 degrees Celsius;

[0036] (2) When the temperature of the vanadium oxide-containing product drops to a predetermined threshold, acid and water are added to the stream, and by controlling the flow acceleration of the acid and water, the target valence electrolyte is continuously produced, wherein the target valence electrolyte is a 3-4 valence vanadium electrolyte.

[0037] When the temperature of the vanadium oxide product drops to a predetermined threshold, acid and water are added simultaneously. Acid releases a significant amount of heat when it meets water. Controlling the rate of acid addition can control the heat output, thereby helping to maintain the temperature of the reaction. During research, it was discovered that using an acid solution rather than a stream of acid and water does not maintain the required reaction temperature. Furthermore, the vanadium oxide product cannot be added until its temperature drops to the predetermined threshold. This results in significant heat loss, poor heat utilization, and prolonged reaction time.

[0038] The predetermined pressure mentioned above is preferably 0.05-0.12 MPa, and can be about 0.05 MPa, 0.06 MPa, 0.07 MPa, 0.08 MPa, 0.09 MPa, 0.10 MPa, 0.11 MPa, or 0.12 MPa according to specific embodiments. By controlling the predetermined pressure to be 0.05-0.12 MPa, it is possible to ensure that the prepared vanadium oxide is granular, increase the specific surface area, and facilitate the dissolution of the vanadium oxide when acid and water are added in the later stage, thereby reducing the dissolution temperature and energy consumption. For example, vanadium oxide usually needs to be above 120 degrees Celsius to dissolve. By controlling the pressure, it is possible to dissolve vanadium oxide at around 60-100 degrees Celsius, thereby significantly reducing energy consumption.

[0039] The predetermined temperature mentioned above can be about 400 degrees Celsius, 450 degrees Celsius, 500 degrees Celsius, 550 degrees Celsius, 600 degrees Celsius, or 650 degrees Celsius, depending on the embodiment. According to a specific embodiment, the reduction time in step (1) is 1.5 to 4 hours. The reduction time is about 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours.

[0040] According to a specific embodiment, the gas generated by the reduction in step (1) includes nitrogen, hydrogen and ammonia, and the flow rate of nitrogen, hydrogen and / or ammonia is controlled by an inlet valve and an outlet valve.

[0041] According to a specific embodiment, the reduction in step (1) is carried out in a reduction furnace, and the stacking ratio of the material in the reduction furnace is 12-18%. The stacking ratio of the material in the reduction furnace refers to the ratio of the volume of the stacked material to the volume of the reduction furnace.

[0042] According to a specific embodiment, the acid in step (2) is sulfuric acid.

[0043] According to a specific embodiment, the flow acceleration of the acid in step (2) is calculated based on the flow addition amount per 1L of water, corresponding to the flow addition of 300g~800g of acid per minute (which can be expressed as 300g / L / min~800g / L / min); according to a preferred embodiment, the flow acceleration of the acid is calculated based on the flow addition amount per 1L of water, corresponding to the flow addition of 500g~800g of acid per minute.

[0044] According to a specific embodiment, the flow acceleration of the water is calculated based on 1g of material, corresponding to the addition of 2-5mL of water per minute (which can be expressed as 2-5ml / g / min).

[0045] According to a specific embodiment, the predetermined threshold mentioned in step (2) is 60 to 110 degrees Celsius, preferably 60 to 100 degrees Celsius, and more preferably 80 to 90 degrees Celsius. The temperature of the vanadium oxide-containing product can be controlled to drop to the predetermined threshold by an external cooling water pipe. For example, it can be about 60 degrees Celsius, about 65 degrees Celsius, about 70 degrees Celsius, about 75 degrees Celsius, about 80 degrees Celsius, about 85 degrees Celsius, about 90 degrees Celsius, about 95 degrees Celsius, about 100 degrees Celsius, about 105 degrees Celsius, or about 110 degrees Celsius. When the predetermined threshold reaches below 110 degrees Celsius, energy consumption can be reduced.

[0046] Referring to Figure 2 , the present disclosure also provides a system for continuous production of electrolyte using ammonium metavanadate. In Figure 2 , 100 represents a reduction furnace, 101 represents an air inlet valve, 102 represents an air outlet valve, 103 represents a feed port, and 104 represents a discharge port. 200 represents a reaction tank, 201 represents an acid feed port, and 202 represents a water feed port.

[0047] The system for continuously producing electrolyte from ammonium metavanadate provided by the present disclosure includes:

[0048] A reduction unit, wherein the reduction unit uses an ammonium metavanadate material to reduce a product containing vanadium oxide in a reduction furnace at a predetermined pressure and a predetermined temperature to obtain a product containing vanadium oxide. The reduction furnace is equipped with an inlet valve and an outlet valve, and the inlet valve and the outlet valve are used to regulate the circulation volume of the gas generated by the reduction. The reduction furnace is equipped with a feed port and a discharge port, the feed port controls the feed rate of the material, and the discharge port controls the outflow of the product. The predetermined pressure is 0.02-0.12 MPa, and the predetermined temperature is 400-650 degrees Celsius.

[0049] An acid addition unit is used to add acid and water when the vanadium oxide-containing product drops to a predetermined threshold value, and by controlling the flow acceleration of the acid and water, continuously produce an electrolyte with a target valence state in a reaction tank, wherein the electrolyte with a target valence state is a 3-4 valence vanadium electrolyte; the acid addition unit is connected to the discharge port of the reduction furnace, and the reaction tank is connected to the acid feed port and the water feed port.

[0050] According to a specific embodiment, the gas generated by the reduction includes nitrogen, hydrogen and / or ammonia, and the circulation amount of nitrogen, hydrogen and / or ammonia is controlled by an inlet valve and an outlet valve.

[0051] According to a specific embodiment, the flow acceleration of the acid feed port is based on the flow rate per 1L of water, corresponding to the flow rate of 300g~800g of acid per minute;

[0052] The flow acceleration of the water feed port is calculated as 2-5 mL of water per minute for every 1 g of material.

[0053] According to a specific embodiment, the reduction furnace is externally connected to a cooling water pipeline, the cooling water pipeline controls the temperature of the vanadium oxide-containing product to drop to a predetermined threshold, and the cooling water pipeline is connected to the water feed port.

[0054] The technical solutions of the present disclosure are described below through specific embodiments. It should be noted that these embodiments are only used to facilitate understanding by those skilled in the art and should not be regarded as limiting the scope of protection of the present disclosure. Example

[0055] Example 1 provides a method for continuously producing vanadium electrolyte using ammonium metavanadate, comprising:

[0056] Ammonium metavanadate is passed through the reduction reactor at a rate of 10 kg / h. The pressure in the furnace is controlled to 0.05 MPa by the air inlet valve and the air outlet valve, and the temperature in the furnace is controlled to 500 degrees Celsius. The reaction is carried out for 3 hours. The material enters the water cooling section and is cooled to 100 degrees Celsius to obtain 3.7-valent vanadium oxide. The vanadium oxide is fed into the reaction tank through a spiral feeder. At the same time, the water flow rate is 2.75 ml.g ‑1 .min ‑1 , sulfuric acid (98%) flow rate is 500g.L ‑1 .min ‑1 Water and sulfuric acid are put into a continuous reaction tank for reaction. The solution after the reaction passes through a thickener, and the supernatant is filtered through a precision filter to obtain a 3.7-valent 3.0mol / L crude vanadium electrolyte. The dense slurry is returned to the reaction tank, and the 3.0mol / L crude electrolyte is modulated to obtain a 1.74mol / L qualified 3.7-valent vanadium electrolyte. Example

[0057] Example 2 provides a method for continuously producing vanadium electrolyte using ammonium metavanadate, comprising:

[0058] Ammonium metavanadate is passed through the reduction reactor at a rate of 12 kg / h. The pressure in the furnace is controlled to 0.1 MPa by the air inlet valve and the air outlet valve, and the temperature in the furnace is controlled to 600 degrees Celsius. The reaction is carried out for 3 hours. The material enters the water cooling section and is cooled to 80 degrees Celsius to obtain 3.1-valent vanadium oxide. The vanadium oxide is fed into the reaction tank through a spiral feeder. At the same time, the water flow rate is 3.5 ml.g ‑1 .min ‑1 , sulfuric acid (98%) flow rate is 800g.L ‑1 .min ‑1 Water and sulfuric acid are put into a continuous reaction tank for reaction. The solution after the reaction passes through a thickener, and the supernatant is filtered through a precision filter to obtain a 3.1-valent 3.0mol / L crude vanadium electrolyte. The dense slurry is returned to the reaction tank, and the 3.0mol / L crude electrolyte is modulated to obtain a 1.8mol / L qualified 3.1-valent vanadium electrolyte.

[0059] In the description of this specification, reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure.

[0060] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A method for continuously producing electrolyte from ammonium metavanadate, characterized in that: include: (1) reducing the ammonium metavanadate material at a predetermined pressure and a predetermined temperature, and obtaining a vanadium oxide-containing product by controlling the gas circulation rate generated by the reduction and the material feed rate, wherein the predetermined pressure is 0.02 to 0.12 MPa, and the predetermined temperature is 400 to 650 degrees Celsius; (2) When the temperature of the vanadium oxide-containing product drops to a predetermined threshold, acid and water are added in a stream, and by controlling the flow acceleration of the acid and water, an electrolyte with a target valence state is continuously produced, wherein the electrolyte with a target valence state is a 3-4 valence vanadium electrolyte.

2. The method according to claim 1, characterized in that The reduction time in step (1) is 1.5 to 4 hours.

3. The method according to claim 1, characterized in that The gas generated by the reduction in step (1) includes nitrogen, hydrogen and / or ammonia, and the circulation amount of nitrogen, hydrogen and / or ammonia is controlled by an inlet valve and an outlet valve.

4. The method according to claim 1, characterized in that: The reduction in step (1) is carried out in a reduction furnace, and the stacking ratio of the material in the reduction furnace is 12-18%.

5. The method according to claim 1, characterized in that The flow acceleration of the acid in step (2) is based on the flow rate per 1L of water, corresponding to 300g~800g of acid per minute; The water flow acceleration is calculated based on 1g of material, corresponding to 2-5mL of water per minute.

6. The method according to claim 1, characterized in that The predetermined threshold in step (2) is 60-110 degrees Celsius, and the temperature of the vanadium oxide-containing product is controlled to drop to the predetermined threshold by an external cooling water pipeline; Optionally, water flowing through the external cooling water pipeline is added into step (2) as supplementary water.

7. A system for continuously producing electrolyte from ammonium metavanadate, characterized in that: include: A reduction unit, wherein the reduction unit uses ammonium metavanadate material to perform reduction in a reduction furnace at a predetermined pressure and a predetermined temperature to obtain a product containing vanadium oxide, the reduction furnace is equipped with an inlet valve and an outlet valve, the inlet valve and the outlet valve are used to regulate the circulation amount of the gas generated by the reduction, the reduction furnace is equipped with a feed port and a discharge port, the feed port controls the feed speed of the material, and the discharge port controls the outflow of the product; the predetermined pressure is 0.02-0.12 MPa, and the predetermined temperature is 400-650 degrees Celsius; An acid adding unit is used to add acid and water when the product containing vanadium oxide drops to a predetermined threshold value, and to continuously produce an electrolyte with a target valence state in a reaction tank by controlling the flow acceleration of the acid and water, wherein the electrolyte with a target valence state is a 3-4 valence vanadium electrolyte; the acid adding unit is connected to the discharge port of the reduction furnace, and the reaction tank is connected to the acid feed port and the water feed port.

8. The system according to claim 7, characterized in that The gas generated by the reduction includes nitrogen, hydrogen and / or ammonia, and the circulation amount of nitrogen, hydrogen and / or ammonia is controlled by an inlet valve and an outlet valve.

9. The system according to claim 7, characterized in that The flow acceleration of the acid feed port is based on the flow rate per 1L of water, corresponding to 300g~800g of acid per minute; The flow acceleration of the water feed port is calculated as 2-5 mL of water per minute for every 1 g of material.

10. The system according to claim 7, characterized in that The reduction furnace is externally connected to a cooling water pipeline, and the cooling water pipeline controls the temperature of the product containing vanadium oxide to drop to a predetermined threshold value. The cooling water pipeline is connected to the water feed port.

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