Method and device for removing ammonia in vanadium-containing solution

Abstract

The invention provides a method and a device for removing ammonia in a vanadium-containing solution. The method for removing ammonia in the vanadium-containing solution comprises the following steps: (1) selectively adding water into a reaction kettle, heating the water in the reaction kettle to 60-80 DEG C, stirring and keeping an air draft state until the reaction in the step (3) is finished; (2) adding the vanadium-containing sample and alkali into a reaction kettle according to a preset feeding speed, and controlling the pH value of the solution in the reaction kettle to be 9.5-11.5; and (3) heating the solution in the reaction kettle to 85-110 DEG C, and carrying out a deamination reaction so as to remove ammonia in the vanadium-containing sample. The method provided by the invention can realize efficient and rapid removal of ammonia, and the removal rate of ammonia reaches 99%-100%.

Description

Technical Field

[0001] The invention relates to the field of vanadium solution treatment, and in particular to a method and a device for removing ammonia from a vanadium-containing solution. Background Art

[0002] With the strategic goal of "carbon peak and carbon neutrality", the scale of new energy storage development in my country has continued to grow rapidly. China's abundant vanadium resources and the unique advantages of all-vanadium flow batteries make it a key player in the development of large-scale energy storage. The cost of electrolyte is one of the main costs of all-vanadium flow batteries, and vanadium pentoxide is a key raw material for the preparation of all-vanadium flow battery electrolytes. High-purity vanadium pentoxide can be obtained by chemical purification of crude ammonium metavanadate. In particular, this method usually dissolves crude ammonium metavanadate first. In order to reduce the loss of vanadium, free ammonia in the solution should be removed as much as possible. Traditional ammonia removal methods are not suitable for removing ammonia from vanadium-containing solutions; in the process of chemical purification of ammonium metavanadate, the breakpoint chlorination method can achieve a 90% ammonia removal rate, but the amount of chlorine used is large, and excessive use will produce chlorinated organic matter and chloramines, which is not suitable for large amounts of high-concentration ammonia-containing solutions. Biological ammonia removal has strict requirements on water quality and is not suitable for vanadium-containing solutions. The steam stripping method has high energy consumption and poor ammonia removal effect. The chemical precipitation method is costly and currently only remains in the laboratory stage.

[0003] Therefore, developing a method for removing ammonia from vanadium-containing solutions is of great strategic significance for the large-scale production of high-purity ammonium metavanadate. Summary of the invention

[0004] In order to improve the deficiencies of the prior art, the present invention proposes a method and device for removing ammonia from a vanadium-containing solution; the provided method and device are particularly suitable for removing ammonia from a vanadium-containing sample, and the entire process does not generate impurity pollution. The ammonia content in the solution after the ammonia is finally removed is detected by nanometer reagent spectrophotometry, and the detection result shows that the method and device can play a good role in removing ammonia, and the ammonia removal rate reaches 99% to 100%.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] In a first aspect of the present invention, the present invention provides a method for removing ammonia from a vanadium-containing solution, comprising:

[0007] (1) selectively adding water into the reaction kettle, heating the water in the reaction kettle to 60° C. to 80° C., stirring and maintaining the exhaust state until the reaction of step (3) is completed;

[0008] (2) adding the vanadium-containing sample and alkali into the reactor at a predetermined feeding rate, and controlling the pH of the solution in the reactor to be 9.5 to 11.5;

[0009] (3) The temperature of the solution in the reaction kettle is heated to 85-110 degrees Celsius to perform a deamination reaction so as to remove ammonia in the vanadium-containing sample.

[0010] According to an embodiment of the present invention, the method for removing ammonia from a vanadium-containing sample may further include the following technical features:

[0011] In some embodiments of the present invention, the vanadium-containing sample is in solid form, and the amount of water added in step (1) is such that after the vanadium-containing sample is dissolved in water, the concentration of the vanadium-containing sample is less than 200 g / L.

[0012] In some embodiments of the present invention, the vanadium-containing sample is in liquid form and the concentration of the vanadium-containing sample is less than 200 g / L, then step (1) is omitted, and the ventilation state is maintained after the vanadium-containing sample and the base are added in step (2) until the reaction is completed in step (3).

[0013] In some embodiments of the present invention, a self-priming stirring paddle is used for stirring in step (1), and the speed of the self-priming stirring paddle is 200-600 rpm, preferably 400-550 rpm.

[0014] In some embodiments of the present invention, an exhaust fan is used for the exhaust, and the air volume of the exhaust fan is controlled to be 1.5 to 4 times the volume of ammonia produced theoretically by the vanadium-containing sample.

[0015] In some embodiments of the present invention, the vanadium-containing sample is selected from at least one of ammonium metavanadate, ammonium polyvanadate, and ammonium vanadate.

[0016] In some embodiments of the present invention, the deamination reaction time in step (3) is 40 min to 240 min.

[0017] In some embodiments of the present invention, the predetermined feeding rate is 40 kg / min to 100 kg / min.

[0018] A second aspect of the present invention provides a device for removing ammonia from a vanadium-containing solution, comprising:

[0019] A reaction unit, wherein the reaction unit comprises a reaction kettle, wherein a heating element is provided in the reaction kettle, wherein the reaction kettle is respectively connected with a water supply element, a stirring element and an exhaust element, wherein water is selectively added to the reaction kettle through the water supply element, and the water in the reaction kettle is heated to 60 to 80 degrees Celsius through the heating element, stirred through the stirring element, and exhausted through the exhaust element;

[0020] A feeding unit, the feeding unit is connected to the reaction unit, and the vanadium-containing sample and the alkali are added to the reactor according to a predetermined mass ratio and a predetermined feeding speed through the feeding unit, and the pH of the solution in the reactor is controlled to be 9.5-11.5;

[0021] A gas recovery unit is connected to the reaction unit, and the solution in the reactor is heated to 85-110 degrees Celsius by a heating element in the reaction unit to perform a deamination reaction. The removed ammonia is recovered by the gas recovery unit to remove ammonia in the vanadium-containing solution.

[0022] In some embodiments of the present invention, the stirring element is a self-priming stirring paddle.

[0023] In some embodiments of the present invention, the air suction element is an air suction fan.

[0024] In some embodiments of the present invention, the feeding unit includes an automatic feeding machine.

[0025] In some embodiments of the present invention, the gas recovery unit includes an ammonia absorption liquid tower.

[0026] In some embodiments of the present invention, the device also includes a control unit, which is connected to the reaction unit, the feeding unit and the gas recovery unit respectively, and controls the start and end of the operations in the reaction unit, the feeding unit and the gas recovery unit through computer software, and controls the negative pressure of the reaction unit to be less than -100Pa through the control unit.

[0027] The beneficial effects achieved by the present invention are at least:

[0028] The present invention provides a method for removing ammonia from a vanadium-containing sample. The provided method utilizes the principle of equilibrium shift and promotes the balance of ammonium ions and ammonia in the solution to move toward the direction of generating ammonia by controlling pH and temperature, which is the first level of control for rapid deamination. Air is blown into the solution during stirring to increase the power of free ammonia escaping from the vanadium-containing solution, thereby realizing the second level of control for rapid deamination. The pressure in the reactor is reduced by exhausting air to form a slight negative pressure, which not only provides a pressure difference between the gas and liquid phases, drives the free ammonia to transfer from the liquid phase to the gas phase, but also reduces the ammonia content in the reactor, thereby realizing the third level of control for rapid deamination.

[0029] The provided device uses a self-priming stirring paddle to blow in air to increase the power for the free ammonia in the vanadium-containing solution to escape, and at the same time controls the stirring speed to reduce the particle size near the gas outlet, so that tiny bubbles carrying ammonia float to the liquid surface; uses an exhaust fan to reduce the pressure in the kettle to form a slight negative pressure, which not only provides a pressure difference between the gas and liquid phases to drive the free ammonia to transfer from the liquid phase to the gas phase, but also reduces the ammonia content in the kettle. The ammonia that is finally released is absorbed and utilized by the absorption tower. This is the third level of control for rapid deammoniation.

[0030] The method or device provided by the present invention can achieve an ammonia removal rate of 99% to 100% under the premise of being economical, environmentally friendly and efficient, meet the production requirements of ammonium metavanadate, and has broad application prospects in the field of ammonia removal from vanadium-containing solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of a device for removing ammonia from a vanadium-containing solution provided according to an embodiment of the present invention, wherein reference numeral 100 is a feeding unit, 200 is a reaction unit, and 300 is a gas recovery unit.

[0032] Figure 2 It is a schematic diagram of the structure of a device for removing ammonia from a vanadium-containing sample provided according to an embodiment of the present invention, wherein reference numeral 100 is a feeding unit, 200 is a reaction unit, 300 is a gas recovery unit, and 400 is a control unit.

[0033] Figure 3 This is a schematic diagram of the structure of a device for removing ammonia from a vanadium-containing sample according to an embodiment of the present invention, wherein reference numeral 101 is a feeder, 201 is an electric heating reactor, 202 is a water supply unit, 203 is a self-priming stirring paddle, 204 is an exhaust fan, and 301 is an ammonia absorption liquid tower. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below. 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 invention, but should not be construed as limiting the present invention.

[0035] The present invention provides a method for removing ammonia from a vanadium-containing solution, and the vanadium-containing sample mentioned can be in liquid form or in solid form. If it is a solid vanadium-containing sample, water can be added to the reactor in advance; if it is a liquid vanadium-containing solution, and the concentration of the vanadium-containing solution is not high, less than 200g / L, it is not necessary to add water to the reactor in advance. Of course, if the concentration of the vanadium-containing solution is too high, water can also be added to the reactor in advance as needed. The vanadium-containing samples mentioned in this article include but are not limited to ammonium metavanadate, ammonium polyvanadate, ammonium vanadate, etc.

[0036] Specifically, when the vanadium-containing sample is in solid form, the method for removing ammonia from the vanadium-containing sample provided by the present invention comprises:

[0037] (1) adding water into a reaction kettle, heating the water in the reaction kettle to 60 to 80 degrees Celsius, stirring and maintaining a ventilation state until the reaction of step (3) is completed;

[0038] (2) adding the vanadium-containing sample and the alkali into the reactor according to a predetermined mass ratio and a predetermined feeding rate, and controlling the pH of the solution in the reactor to be 9.5 to 11.5;

[0039] (3) The temperature of the solution in the reactor is heated to 85-95 degrees Celsius to perform a deamination reaction so as to remove ammonia from the vanadium-containing solution.

[0040] During the research process, it was found that the amount of water added should not be too much or too little. Too little will affect the removal effect of ammonia, and too much will also cause low efficiency, resulting in waste. The amount of water added can be controlled so that after the vanadium-containing sample is added, the concentration of the vanadium-containing sample is 90-200 g / L (according to the preferred embodiment, the concentration of the vanadium-containing solution is 150-180 g / L). According to a specific embodiment, in step (1), the amount of water added is 0.35-0.6 times the volume of the reactor.

[0041] The temperature of the added water is 25-70°C, for example, it can be water at room temperature, as long as the temperature is not too high, and is not higher than the temperature of the deamination reaction.

[0042] When stirring, a self-priming stirring paddle can be used. Compared with a common stirring paddle, the self-priming stirring paddle can make tiny bubbles carrying ammonia float to the liquid surface while blowing air, thereby making the removal rate of ammonium ions higher. According to a specific embodiment, the speed of the self-priming stirring paddle is controlled at 200-600rpm, preferably 400-550rpm.

[0043] The exhaust fan is used to extract air, and the exhaust fan is used to reduce the pressure in the kettle to form a slight negative pressure, which not only provides a pressure difference between the gas and liquid phases, drives the free ammonia to transfer from the liquid phase to the gas phase, but also reduces the ammonia content in the kettle. The ammonia that is finally separated is absorbed and utilized by the absorption tower. According to the specific implementation method, the air volume of the exhaust fan is controlled at 1.5 to 4 times the theoretical volume of ammonia produced by the vanadium-containing solution.

[0044] After adding alkali in step (2), the main purpose is to control the pH of the solution in the reactor within a certain range. During the research, it was found that if the pH value is too high, the cost will increase, and if the pH is too low, the deamination effect will be affected. According to a preferred embodiment, the pH of the solution in the reactor in step (2) is controlled to be 10.5-11.5. According to a specific embodiment, the mass ratio of the vanadium-containing sample to the alkali is 1:0.38-0.7, thereby ensuring that the pH value of the solution is 9.5-11.5, preferably 10.5-11.5.

[0045] According to a specific implementation manner, in the step (2), the feeding rate is 40kg / min to 100kg / min.

[0046] According to a preferred embodiment, the temperature of the deamination reaction is controlled at 95°C to 110°C, and the reaction time is 40min to 240min. During the research, it was found that if the temperature of the deamination reaction is too low, the deamination effect becomes poor; if the temperature is too high, the cost is affected.

[0047] The present invention also provides a device for removing ammonia from a vanadium-containing sample, as shown in Figure 1 As shown, including:

[0048] The reaction unit 200 includes a reaction kettle, in which a heating element is provided. The reaction kettle is respectively connected with a water supply element, a stirring element and an exhaust element. Water is selectively added to the reaction kettle through the water supply element, the water in the reaction kettle is heated to 60 to 80 degrees Celsius through the heating element, stirred by the stirring element, and exhausted by the exhaust element;

[0049] A feeding unit 100, wherein the feeding unit 100 is connected to the reaction unit 200, and the vanadium-containing sample and the alkali are added to the reactor according to a predetermined mass ratio and a predetermined feeding speed through the feeding unit, and the pH of the solution in the reactor is controlled to be 9.5-11.5;

[0050] A gas recovery unit 300 is connected to the reaction unit, and uses a heating element in the reaction unit to heat the solution in the reactor to 85-95 degrees Celsius to perform a deammoniation reaction. The removed ammonia is recovered by the gas recovery unit to remove ammonia in the vanadium-containing solution.

[0051] According to a specific embodiment, the stirring element is a self-priming stirring paddle.

[0052] According to a specific embodiment, the air suction element is an exhaust fan.

[0053] According to a specific embodiment, the feeding unit includes an automatic feeding machine.

[0054] According to a specific embodiment, the gas recovery unit includes an ammonia absorption liquid tower.

[0055] According to a specific embodiment, the device is as follows Figure 2 As shown, a control unit 400 is also included, and the control unit is communicated with the reaction unit, the feeding unit and the gas recovery unit respectively, and the opening and closing of the operation in the reaction unit, the feeding unit and the gas recovery unit are controlled by computer software, and the negative pressure of the reaction unit is controlled by the control unit to be not higher than -100Pa. The specific control unit can realize the control of the negative pressure of the reaction unit by a regulating valve, so as to ensure the balance of the gas pressure in the reaction unit. It was found during the research process that the reaction unit has a slight negative pressure, for example, about -100Pa.

[0056] According to a specific embodiment, the provided device for removing ammonia from a vanadium-containing sample can also be used as follows: Figure 3 As shown, 101 is a feeder, 201 is an electric heating reactor, 202 is a water supply unit, 203 is a self-priming stirring paddle, 204 is an exhaust fan, and 301 is an ammonia absorption liquid tower. Adding alkali to the electric heating reactor 201 filled with vanadium solution, ammonia dissolving in water is an exothermic reaction, and a large amount of heat will be generated after the alkali dissolves and a large amount of OH will be provided. - From the perspective of equilibrium shift, increasing temperature and pH will promote the equilibrium in the solution: NH3+H2O→NH 4+ +OH - Move to the left, that is, promote the transfer of free ammonia in the liquid phase to the gas phase. In addition, at the same time, an exhaust port is opened on the upper part of the electric reactor and an exhaust fan that provides negative pressure is equipped to realize the extraction of free ammonia on the liquid surface. The stirring shaft of the electric reactor is made into a hollow structure with pores at the upper and lower ends. Air is inhaled as stirring begins and discharged from the exhaust port of the stirring paddle to form bubbles, which are then broken into many small bubbles by the stirring paddle. The pressure in the liquid phase increases with the continuous inhalation of air and the increase in temperature. This additional pressure also provides a driving force for the escape of ammonia in the solution. Controlling pH, temperature and a certain negative pressure can greatly improve the degree of conversion of ammonium ions to ammonia. The separated ammonia is recycled through the ammonia absorption liquid tower to achieve a clean and efficient deammoniation process.

[0057] The technical scheme of the present invention is described below by specific examples. It should be noted that these examples are only used to facilitate the understanding of those skilled in the art and should not be regarded as limiting the scope of protection of the present invention. The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0058] Example 1

[0059] Example 1 Ammonia in a vanadium-containing sample is removed by the following method, comprising:

[0060] 4 tons of water at 20°C is poured into a 10m 3 The reactor was heated to 60°C, the self-priming stirring blade was turned on, and the stirring rate was controlled to 400 rpm. The exhaust fan was turned on and the air volume was controlled to 500 m 3 / h, start the automatic feeder, add ammonium vanadate and alkali in a mass ratio of 1:0.45 into the reactor at a feeding rate of 50kg / min, and control the pH of the reactor solution to 9.5. Continue to raise the temperature to 90℃, keep the temperature for 60min, and carry out the deamination reaction.

[0061] The ammonium ion concentration in the solution after the reaction was detected to be 0.1 g / L. Compared with the ammonium ion concentration of the ammonium vanadate sample before the treatment after being dissolved in water, the removal rate of ammonium ions by the method provided in Example 1 was 99.7%.

[0062] Example 1a

[0063] In Example 1a, the "self-priming stirring paddle" of Example 1 is replaced with an "ordinary stirring paddle", and other implementation conditions are carried out in the same manner as in Example 1.

[0064] Example 1b

[0065] Example 1b: Change the method of Example 1 to "turn on the exhaust fan and control the air volume to 500m 3 / h" is replaced with "do not turn on the exhaust fan", and other implementation conditions are carried out in the same manner as in Example 1.

[0066] The comparison results of ammonium removal effects are shown in Table 1 below:

[0067] Table 1 Treatment results of different embodiments

[0068] Serial number Ammonium ion concentration in the solution after reaction (g / L) Ammonium ion removal rate (%) Example 1 0.10 99.69 Example 1a 2.53 92.08 Example 1b 4.20 86.86

[0069] Example 2

[0070] Example 2 Ammonia in a vanadium-containing sample is removed by the following method, comprising:

[0071] 4 tons of water at 20°C is poured into a 10m 3 The reactor was heated to 60°C, the self-priming stirring blade was turned on, and the stirring rate was controlled to 400 rpm. The exhaust fan was turned on and the air volume was controlled to 400 m 3 / h, start the automatic feeder, add ammonium vanadate and alkali in a mass ratio of 1:0.55 into the reactor at a feeding rate of 50kg / min, and control the pH of the reactor solution to 10. After the temperature is continuously raised to 90°C, keep the temperature for 90 minutes to carry out the deamination reaction.

[0072] The concentration of ammonium ions in the solution after the reaction was detected to be 0.08 g / L. Compared with the concentration of ammonium ions after the ammonium vanadate sample was dissolved in water before the treatment, the removal rate of ammonium ions by the method provided in Example 2 was 99.75%.

[0073] Example 2a

[0074] Example 2a: The "stirring rate is 400 rpm" in Example 2 is replaced by "stirring rate is 500 rpm", and other implementation conditions are carried out in the same manner as in Example 2.

[0075] Example 2b

[0076] Example 2b: Change the "turn on the exhaust fan, control the air volume to 400m 3 / h" is replaced with "do not turn on the exhaust fan", and other implementation conditions are carried out in the same manner as in Example 2.

[0077] The comparison results of ammonium removal effects are shown in Table 2 below:

[0078] Table 2 Treatment results of different embodiments

[0079] Serial number Ammonium ion concentration in the solution after reaction (g / L) Ammonium ion removal rate (%) Example 2 0.08 99.75 Example 2a 0.05 99.84 Example 2b 3.80 88.11

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific implementation", etc. 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 invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for removing ammonia from a vanadium-containing solution, characterized in that: include: (1) selectively adding water into the reaction kettle, heating the water in the reaction kettle to 60 to 80 degrees Celsius, stirring and maintaining the exhaust state until the reaction of step (3) is completed; (2) adding the vanadium-containing sample and alkali into a reactor at a predetermined feeding rate, and controlling the pH of the solution in the reactor to be 9.5 to 11.5; (3) The temperature of the solution in the reaction kettle is heated to 85-110 degrees Celsius to perform a deamination reaction so as to remove ammonia from the vanadium-containing sample.

2. The method according to claim 1, characterized in that The vanadium-containing sample is in solid form, and the amount of water added in step (1) is such that after the vanadium-containing sample is dissolved in water, the concentration of the vanadium-containing sample is 90 to 200 g / L.

3. The method according to claim 1, characterized in that The vanadium-containing sample is in liquid form. If the concentration of the vanadium-containing sample is less than 200 g / L, step (1) is omitted, and the evacuation state is maintained after the vanadium-containing sample and the base are added in step (2) until the reaction is completed in step (3).

4. The method according to claim 1, characterized in that: In step (1), a self-priming stirring paddle is used for stirring, and the speed of the self-priming stirring paddle is 200-600 rpm, preferably 400-550 rpm.

5. The method according to claim 1, characterized in that The exhaust fan is used for the exhaust, and the air volume of the exhaust fan is controlled to be 1.5 to 4 times the volume of the theoretical ammonia produced by the vanadium-containing sample.

6. The method according to claim 1, characterized in that The vanadium-containing sample is selected from at least one of ammonium metavanadate, ammonium polyvanadate, and ammonium vanadate; Optionally, the deamination reaction time in step (3) is 40 min to 240 min.

7. The method according to claim 1, characterized in that The predetermined feeding speed is 40kg / min to 100kg / min.

8. A device for removing ammonia from a vanadium-containing solution, characterized in that: include: A reaction unit, wherein the reaction unit comprises a reaction kettle, wherein a heating element is provided in the reaction kettle, wherein the reaction kettle is respectively connected with a water supply element, a stirring element and an exhaust element, wherein water is selectively added to the reaction kettle through the water supply element, and the water in the reaction kettle is heated to 60 to 80 degrees Celsius through the heating element, stirred through the stirring element, and exhausted through the exhaust element; A feeding unit, the feeding unit is connected to the reaction unit, and the vanadium-containing sample and the alkali are added to the reactor according to a predetermined mass ratio and a predetermined feeding speed through the feeding unit, and the pH of the solution in the reactor is controlled to be 9.5-11.5; A gas recovery unit is connected to the reaction unit, and the solution in the reactor is heated to 85-110 degrees Celsius by a heating element in the reaction unit to perform a deamination reaction. The removed ammonia is recovered by the gas recovery unit to remove ammonia in the vanadium-containing solution.

9. The device according to claim 8, characterized in that The stirring element is a self-priming stirring paddle; Optionally, the air extraction element is an exhaust fan; Optionally, the feeding unit comprises an automatic feeding machine, Optionally, the gas recovery unit comprises an ammonia absorption tower.

10. The device according to claim 8, characterized in that It also includes a control unit, which is connected to the reaction unit, the feeding unit and the gas recovery unit respectively, and controls the start and end of the operations in the reaction unit, the feeding unit and the gas recovery unit through computer software, and controls the negative pressure of the reaction unit to be no higher than -100Pa through the control unit.

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