Method for removing arsenic in vanadium-containing solution

Abstract

The invention belongs to the field of vanadium batteries, and particularly relates to a method for removing arsenic in a vanadium-containing solution. The method comprises the following steps: (1) providing a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5; (2) mixing the vanadium-containing solution with an impurity removing agent, adjusting the pH value of the mixed solution to 6.0-9.0, reacting for 0.5-2.5 hours, and filtering to obtain an impurity-removed solution and impurity-removed slag; (3) the impurity removal liquid is subjected to vanadium precipitation treatment, and vanadate is obtained; and (4) dissolving the impurity-removed slag through a dissolving solution, and recovering the obtained solution to the step (1) for recycling. By applying the method and the device provided by the invention, the arsenic content can be reduced to 0.01-10mg / L or below, meanwhile, the vanadium loss rate can be controlled to be 1-10%, the impurity removal effect is good, and the impurity removal cost is low.

Description

Technical Field

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

[0002] Large-scale and efficient energy storage technology has gradually become a research hotspot in the field of new energy, and safety issues are a key factor in the development of the energy storage industry. Lithium battery and sodium-sulfur battery energy storage power stations frequently have safety problems. Against this background, all-vanadium flow batteries stand out in the large-scale energy storage track with their high safety, long service life, and adjustable power. Vanadium electrolyte, as the active substance of all-vanadium redox flow batteries, is a key component of vanadium batteries and directly affects battery performance. The electrolyte process is long and the composition system is complex. In order to maintain the electrochemical properties of the electrolyte, there are strict requirements for the content of trace elements. Arsenic (As) is toxic to water and human bodies, and also has side effects on the charging and discharging performance of vanadium batteries. Therefore, the arsenic content in vanadium electrolyte is required to be less than 0.5ppm. Commonly used vanadium raw materials, such as ammonium metavanadate, ammonium polyvanadate, vanadium pentoxide, etc., are difficult to remove and the cost of impurities is high when they are purified to prepare battery-grade vanadium raw materials, resulting in high prices and small quantities of battery-grade vanadium raw materials. It is urgent to develop a technical method for arsenic in vanadium-containing solutions.

[0003] At present, arsenic removal technologies at home and abroad can be roughly divided into chemical precipitation arsenic removal, adsorption arsenic removal, ion exchange arsenic removal, electrodialysis arsenic removal, membrane arsenic removal, biological arsenic removal, etc. For example, in CN201910746343, arsenic is removed by chemical precipitation through coagulation reaction between polyferric sulfate and flocculant and arsenic in water. Adsorption methods such as CN201210056801, CN201210122816, and CN201911416111 use adsorbents with large specific surface areas or adsorption groups such as activated carbon and iron-aluminum oxide to selectively remove arsenic in the form of arsenate / arsenite in water. Ion exchange methods such as CN201010242923 use functional resins to achieve the purpose of arsenic removal, and the treatment volume is relatively small. If there are a large number of anions such as sulfate and phosphate in the treated liquid, it will affect the arsenic removal efficiency, and it is not suitable for arsenic removal in the field of vanadium-sulfuric acid system electrolyte. The electrodialysis method passes the arsenic-containing waste liquid through two polar membranes, so that the anions and cations in the waste water move and enrich, so that the arsenic-containing waste water can be purified. The electrodialysis method has high power consumption and high equipment requirements, and is not suitable for large-scale application. Membrane arsenic removal utilizes the dialysis effect of the membrane. This method is relatively simple, but the arsenic removal effect is not good when used alone, and it increases the cost when used in conjunction with other arsenic removal methods. Biological methods such as CN202211222885 use functional proteins secreted or loaded by microorganisms to react with arsenic to achieve the purpose of arsenic removal. The biological method has less pollution, but the cycle is long, the technology is immature, and the process has a narrow scope of application. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for removing arsenic from a vanadium-containing solution, aiming to solve the problems of the existing difficulty in arsenic removal, high arsenic removal cost, large loss of impurity vanadium, low resource utilization, etc. The present invention takes into account the treatment process, economic cost, solution treatment volume, arsenic removal effect, etc., and selects chemical precipitation-filtration to remove arsenic from the vanadium electrolyte, for example, using an impurity remover (such as aluminum salt hydrolysis product surface hydroxyl site adsorbing arsenic to form a co-precipitate, or impurity ions and aluminum salt hydrolysis products forming flocculent aluminum salt precipitation, which is adsorbed by the aluminum salt hydrolysis product) to aggregate arsenic in the form of precipitation, and filtering to remove most of the impurity arsenic in the vanadium-containing solution.

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

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

[0007] (1) providing a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5;

[0008] (2) mixing the vanadium-containing solution and the impurity remover described in step (1), adjusting the pH of the mixed solution to 6.0-9.0, reacting for 0.5-2.5 hours, and filtering to obtain an impurity-removing liquid and impurity-removing residue;

[0009] (3) subjecting the impurity removal solution obtained in step (2) to vanadium precipitation to obtain vanadate;

[0010] (4) The impurity-removed residue obtained in step (2) is dissolved by a dissolving solution, and the obtained solution is recovered to step (1) for recycling.

[0011] The method provided by the present invention can reduce the arsenic content to below 0.01-10 mg / L, and can control the vanadium loss rate to 1-10%. The method provided by the present invention has not only good impurity removal effect, but also low impurity removal cost and strong raw material adaptability.

[0012] According to an embodiment of the present invention, the method for removing arsenic from a vanadium-containing solution may further include the following technical features:

[0013] According to an embodiment of the present invention, step (1) further comprises: if the valence of vanadium in the vanadium-containing solution is lower than 5, performing oxidation pretreatment on the vanadium-containing solution in advance, and the valence of vanadium in the vanadium-containing solution after the oxidation pretreatment is 5.

[0014] According to an embodiment of the present invention, the vanadium-containing solution is selected from at least one of a vanadium extraction leaching solution, a vanadium extraction enrichment solution, and a solid vanadium dissolving solution.

[0015] According to an embodiment of the present invention, the solid vanadium solution is a vanadium-containing solution prepared by dissolving a vanadium-containing raw material in an alkaline solution, and the alkaline solution is selected from at least one of sodium bicarbonate, sodium percarbonate, sodium carbonate, calcium carbonate, ammonium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0016] According to an embodiment of the present invention, step (2) further comprises: heating the vanadium-containing solution described in step (1) to no more than 90 degrees Celsius, mixing it with an impurity remover and polyacrylamide, adjusting the pH of the mixed solution to 6.0-9.0, reacting for 0.5-2.5 hours, and filtering to obtain an impurity removal liquid and impurity removal residue.

[0017] According to an embodiment of the present invention, in the step (2), the impurity remover is selected from at least one of sodium sulfide, sodium phosphate, aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum silicate, aluminum phosphate, aluminum titanate, aluminum sulfide, sodium aluminate, alum, ethyl aluminum phosphate, activated alumina, aluminum nitride, aluminum glycolate, aluminum carbide, aluminum hydroxide, lanthanum aluminum oxide, sodium aluminosilicate, sodium aluminosilicate, vanadium aluminum carbide, and titanium aluminum carbide.

[0018] The dosage of the impurity remover is 1-8w% of the mass of the vanadium-containing solution.

[0019] According to an embodiment of the present invention, in step (2), the acid used to adjust the pH of the solution is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, carbonic acid, oxalic acid, and perchloric acid;

[0020] In the step (2), the base used to adjust the pH of the solution is selected from at least one of sodium hydroxide, calcium hydroxide, ammonia water, and sodium carbonate.

[0021] According to an embodiment of the present invention, the dissolving liquid in step (4) is at least one of pure water, ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium oxalate, ammonium acetate, sodium carbonate, sodium hydroxide, and sodium bicarbonate;

[0022] The concentration of the dissolving solution in step (4) is 0 to 10 w%.

[0023] In a second aspect of the present invention, a device for removing arsenic from a vanadium-containing solution is provided, comprising:

[0024] A raw material supply unit, the raw material supply unit is used to provide a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5;

[0025] An impurity removal unit, the impurity removal unit is connected to the raw material supply unit, and is used to heat the vanadium-containing solution and mix it with an impurity remover, adjust the pH of the mixed solution to 6.0-9.0, react for 0.5-2.5 hours, and filter to obtain an impurity removal liquid and impurity removal residue;

[0026] A precipitation unit, the precipitation unit is connected to the impurity removal unit, and the precipitation unit is used to treat the impurity removal liquid and reverse vanadium precipitation to obtain vanadate;

[0027] A dissolving unit is connected to the impurity removal unit and the raw material supply unit. The dissolving unit performs solution treatment on the impurity removal residue by means of a dissolving liquid, and the obtained solution is recovered to the raw material supply unit for recycling.

[0028] According to an embodiment of the present invention, the raw material supply unit further comprises: if the valence of vanadium in the vanadium-containing solution is lower than 5, the vanadium-containing solution is pre-oxidized and pre-treated, and the valence of vanadium in the vanadium-containing solution after the oxidation pre-treatment is 5.

[0029] According to an embodiment of the present invention, the vanadium-containing solution is selected from at least one of a vanadium extraction leaching solution, a vanadium extraction enrichment solution, and a solid vanadium dissolving solution.

[0030] The solution provided by the present invention has at least the following beneficial effects:

[0031] The present invention can reduce the arsenic content to 0.01-10 ppm through one impurity removal by regulating parameters such as pH, reaction temperature, reaction time, reaction molar ratio and the like of the alkaline vanadium-containing solution, and the removal effect reaches more than 99%, and the impurity removal process is simple and the energy consumption is low.

[0032] The present invention makes full use of the raw material characteristics of the impurity removal slag, adopts a reprocessing method, recovers vanadium and impurity removal agents in the impurity removal slag, and returns them to the process, thereby greatly reducing vanadium loss and impurity removal agent consumption, reducing production costs, and realizing resource utilization.

[0033] The vanadate product prepared by the present invention has a low arsenic content of 0.01-2 mg / Kg, which fully meets the standard requirements for vanadate for electrolysis.

[0034] In the process of removing impurities, the present invention not only removes arsenic, but also removes impurity ions such as titanium, molybdenum, manganese, chromium, silicon, etc. in the solution. The removal rate of these impurity ions reaches 60% to 90%. Therefore, while removing arsenic, other impurity ions in the vanadium-containing solution are also removed, reducing the number of impurity removal steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A method for removing arsenic from a vanadium-containing solution is provided according to an embodiment of the present invention.

[0036] Figure 2 The invention discloses a device for removing arsenic from a vanadium-containing solution according to an embodiment of the invention. DETAILED DESCRIPTION

[0037] 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.

[0038] The present invention provides a method for removing arsenic from a vanadium-containing solution, such as Figure 1 Shown include:

[0039] S10: providing a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5.

[0040] The vanadium-containing solution mentioned herein is a vanadium solution of a certain concentration, including but not limited to vanadium extraction leaching solution, vanadium extraction enrichment solution, solid dissolution preparation of vanadium solution, etc., as long as the valence of vanadium in the vanadium-containing solution is 5. If the valence of vanadium in the vanadium-containing solution is less than 5 (for example, 4), the vanadium-containing solution needs to be pretreated to oxidize it to 5, for example, by adding an oxidant to oxidize the vanadium valence of the solution to 5. According to a specific embodiment, the available oxidants include but are not limited to sodium chlorate, hydrogen peroxide, and perchloric acid.

[0041] The solid vanadium solution mentioned herein is a vanadium solution with a valence of 5, which is prepared by dissolving a vanadium solution with an alkali. Available alkalis include, but are not limited to, sodium bicarbonate, sodium percarbonate, sodium carbonate, calcium carbonate, ammonium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like.

[0042] According to a specific embodiment, the solid vanadium solution is prepared by the following method: adding a solid vanadium-containing raw material to water, adding an alkaline reagent according to a molar ratio of alkaline reagent to solid vanadium-containing raw material of 1:0.4 to 1:3, heating the solution to 60 to 90°C, reacting for 0.5 to 2 hours, so that the solid vanadium-containing raw material is fully alkali-dissolved to obtain a vanadium-containing solution with a valence of 5. The total vanadium concentration is 70 to 120 g / L (in terms of V2O5), and the pH is 9.5 to 11.5.

[0043] S20: Mix the vanadium-containing solution and the impurity remover described in S10, adjust the pH of the mixed solution to 6.0-9.0, react for 0.5-2.5 hours, and filter the mixed solution to obtain an impurity removal liquid and impurity removal residue.

[0044] Available impurity removers include, but are not limited to, one or more of sodium sulfide, sodium phosphate, aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum silicate, aluminum phosphate, aluminum titanate, aluminum sulfide, sodium aluminate, alum, ethyl phosphite, activated alumina, aluminum nitride, aluminum glycolate, aluminum carbide, aluminum hydroxide, lanthanum aluminum oxide, sodium aluminosilicate, sodium aluminosilicate, vanadium aluminum carbide, and titanium aluminum carbide. According to a preferred embodiment, the impurity remover is an aluminum salt.

[0045] When the dosage of the impurity remover is too high, the loss of the vanadium-containing solution will be relatively large, and when the dosage of the impurity remover is too low, the impurity removal effect of the vanadium-containing solution is not ideal. According to a specific embodiment, the dosage of the impurity remover is 1-8w% of the mass of the vanadium-containing solution.

[0046] According to a specific implementation, the vanadium-containing solution may be preheated, for example, heated to no more than 90 degrees Celsius, and then mixed with the impurity remover, and the pH of the mixed solution is adjusted to 6.0-9.0. After reacting for 0.5-2.5 hours, the impurity removal liquid and impurity removal residue are obtained by filtration.

[0047] In addition to adding impurity removers, polyacrylamide can also be added as needed. When the impurity content is relatively high, adding polyacrylamide in addition to impurity removers will have a better effect.

[0048] The pH of the solution can be adjusted by acid or alkali. According to a preferred embodiment, the pH of the solution is adjusted to 6 to 8. By adjusting the pH, the impurity removal effect of the vanadium-containing solution is good, otherwise the arsenic in the vanadium-containing solution cannot be effectively removed. According to a specific embodiment, the acid used to adjust the pH of the solution can be one or more of hydrochloric acid, sulfuric acid, phosphoric acid, carbonic acid, oxalic acid, and perchloric acid. According to a specific embodiment, the alkali used to adjust the pH of the solution can be one or more of sodium hydroxide, calcium hydroxide, ammonia water, and sodium carbonate.

[0049] S30: subjecting the obtained impurity removal liquid to vanadium precipitation treatment to obtain vanadate.

[0050] The vanadium precipitation treatment is performed by adding ammonium salt. According to a specific embodiment, the ammonium salt includes but is not limited to at least one of ammonium sulfate, ammonium carbonate, ammonium oxalate, and ammonium chloride. The arsenic content of the vanadate obtained after the vanadium precipitation treatment is 0.01-2 mg / Kg.

[0051] S40: After the obtained impurity-removing slag is dissolved by a dissolving solution, the obtained recovery solution is returned to S10 for recycling.

[0052] The dissolving liquid used is one or more of pure water, ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium oxalate, ammonium acetate, sodium carbonate, sodium hydroxide, and sodium bicarbonate.

[0053] According to a specific embodiment, the mass concentration of the dissolving solution is 0 to 10 wt %. According to a preferred embodiment, the mass concentration of the dissolving solution is 1 to 10 wt %.

[0054] According to the specific implementation method, the dissolution conditions in step (4) are: solid-liquid ratio of 1:0.5-5, dissolution temperature of room temperature, dissolution time of 0.2-2h. After the dissolution treatment, the vanadium recovery rate of the solution is greater than 95%, and the impurity removal agent recovery is greater than 50%, thereby realizing the secondary utilization of aluminum resources.

[0055] The present invention also provides a device for removing arsenic from a vanadium-containing solution, such as Figure 2 As shown, including:

[0056] A raw material supply unit 100, wherein the raw material supply unit 100 is used to provide a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5;

[0057] The impurity removal unit 200 is connected to the raw material supply unit 100, and is used to heat the vanadium-containing solution to room temperature to 90 degrees Celsius, add an impurity remover, adjust the solution pH to 6.0 to 9.0, react for 0.5 to 2.5 hours, and filter to obtain an impurity removal liquid and impurity removal residue;

[0058] A precipitation unit 300, the precipitation unit 300 is connected to the impurity removal unit 200, and the precipitation unit 300 is used to treat the impurity removal liquid and reverse vanadium precipitation to obtain vanadate;

[0059] The dissolving unit 400 is connected to the impurity removal unit 200 and the raw material supply unit 100. The dissolving unit 400 performs solution treatment on the impurity removal residue by using a dissolving liquid, and the obtained solution is recycled to the raw material supply unit for recycling.

[0060] According to an embodiment of the present invention, the raw material supply unit further comprises: if the valence of vanadium in the vanadium-containing solution is lower than 5, the vanadium-containing solution is pre-oxidized and pre-treated, and the valence of vanadium in the vanadium-containing solution after the oxidation pre-treatment is 5.

[0061] According to an embodiment of the present invention, the vanadium-containing solution is selected from at least one of a vanadium extraction leaching solution, a vanadium extraction enrichment solution, and a solid vanadium dissolving solution.

[0062] 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.

[0063] Example 1

[0064] Example 1 Using 95-98 grade vanadium pentoxide produced in a certain place in Shaanxi as raw material, the arsenic therein is removed by the following method. The basic conditions of the raw materials used are: 95-98 grade vanadium pentoxide produced in a certain place in Shaanxi, and the chemical composition detection of each kilogram of vanadium raw material shows that the arsenic content is 15-30 mg, the silicon content is 500-650 mg, the chromium content is 400-500 mg, and other impurities.

[0065] The specific technical method for removing arsenic includes the following steps:

[0066] (1) Take the above solid vanadium material and dissolve it to prepare a vanadium solution. Take 70g of vanadium pentoxide, add it to 0.5L of pure water, add 30g of sodium carbonate alkaline reagent, heat to 60°C, and react for 2h. Filter and cool to obtain an alkaline vanadium-containing solution with a total vanadium content of 85-90g / L (calculated as vanadium pentoxide) and a solution pH of 9.5-11.5.

[0067] (2) The vanadium-containing solution obtained in step (1) is heated to 50° C., 1.5 g of aluminum sulfate or aluminum sulfate solution is added, and the pH value of the solution is adjusted to 6-7.5 with sulfuric acid or sodium hydroxide. The reaction is carried out for 0.5 h, and the solution is filtered to obtain a decontaminated liquid (i.e., a filtrate) and a decontaminated residue (i.e., a filter residue), wherein the total vanadium content in the filtrate is measured to be 75-80 g / L.

[0068] (3) adding ammonium sulfate to the impurity removal solution obtained in step (2) at an ammonium addition coefficient of 1.5 times (i.e., adding ammonium sulfate in an amount of 1.5 times the total mass of vanadium in the solution), and subjecting the solution to vanadium precipitation to obtain an ammonium metavanadate product.

[0069] (4) The impurity-removed residue obtained in step (2) is washed once with pure water at a ratio of L:S (mass ratio of liquid to solid) = 2:1. The washing filtrate can be returned to step (1) for recycling. The vanadium loss is calculated to be 0.5-5%wt.

[0070] The obtained ammonium metavanadate product was tested to have a main vanadium pentoxide content of more than 99.5%. The ICP test of the ammonium metavanadate solution showed that the arsenic content was less than 10ppm, the aluminum was less than 20ppm, and the silicon was less than 10ppm. The results showed that the impurity content of the ammonium metavanadate obtained after impurity removal and vanadium precipitation met the requirements of battery-grade vanadium materials.

[0071] Example 2

[0072] Example 2: Using ammonium metavanadate produced in a certain place in Shandong as raw material, the arsenic therein is removed by the following method. The basic situation of the raw materials used is: ammonium metavanadate produced in a certain place in Shandong, the arsenic content per kilogram of vanadium raw material is as high as 500-700 mg, the silicon content is 100-300 mg, the sodium content is 500-800 mg, and other impurities. The metavanadate used in this case has less other impurities, but the arsenic content is very high, which is not suitable as a raw material for vanadium electrolyte.

[0073] The specific technical method for removing arsenic includes the following steps:

[0074] (1) Dissolve the solid vanadium material to prepare a vanadium solution. Take 75g of ammonium metavanadate, add it to 0.5L of pure water, add 25g of sodium hydroxide alkaline reagent, heat to 70°C, and react for 1h. Filter and cool to obtain an alkaline vanadium-containing solution with a total vanadium content of 90-105g / L (in terms of vanadium pentoxide) and a solution pH of 9.5-11.5.

[0075] (2) The vanadium-containing solution obtained in step (1) is heated to 65° C., 3 g of aluminum hydroxide or aluminum hydroxide solution is added, and the pH value of the solution is adjusted to 7-8.5 with hydrochloric acid or calcium hydroxide. The reaction is carried out for 1 hour, and the solution is filtered to obtain a decontaminated liquid (i.e., a filtrate) and a decontaminated residue (i.e., a filter residue), wherein the total vanadium content in the filtrate is measured to be 85-100 g / L.

[0076] (3) adding ammonium chloride at a rate of 2.5 times the ammonium addition coefficient to the impurity-removing liquid obtained in step (2), and subjecting the mixture to vanadium precipitation treatment to obtain a vanadate product after impurity removal.

[0077] (4) The impurity-removed residue obtained in step (2) is washed twice with pure water according to L:S=3:1. The washing filtrate can be returned to step (1) for recycling. The vanadium loss is calculated to be 1-6.5%wt.

[0078] The arsenic content of the vanadate product after impurity removal is less than 2mg / Kg. The vanadate product after impurity removal is dissolved, reduced by a reducing agent, extracted by an extractant, and stripped by a stripping agent to obtain a high-concentration tetravalent electrolyte product. After testing, the total vanadium concentration of the electrolyte product is about 180-200g / L. The ICP test shows that the content of arsenic, silicon, aluminum, sodium and other impurity ions in the vanadium material meets the requirements of the electrolyte of the all-vanadium liquid flow battery.

[0079] Example 3

[0080] Example 3 Using ammonium metavanadate produced in a certain place in Shaanxi as raw material, the arsenic therein is removed by the following method. The basic information of the raw materials used is: ammonium metavanadate produced in a certain place in Shaanxi, and the chemical composition detection of each kilogram of vanadium raw material shows that the arsenic content is 200-350 mg, the silicon content is 100-200 mg, the chromium content is 100-200 mg, and other impurities.

[0081] The specific technical method for removing arsenic includes the following steps:

[0082] (1) Take the above solid vanadium material and dissolve it to prepare a vanadium solution. Take 60g of ammonium metavanadate, add it to 0.5L of pure water, add 35g of calcium carbonate alkaline reagent, heat to 80°C, and react for 1.5h. Filter and cool to obtain an alkaline vanadium-containing solution with a total vanadium content of 85-90g / L (calculated as vanadium pentoxide) and a solution pH of 9.5-11.5.

[0083] (2) The vanadium-containing solution obtained in step (1) is heated to 70° C., 3.75 g of sodium aluminosilicate is added, and the pH value of the solution is adjusted to 8-9 with phosphoric acid or aqueous ammonia. The mixture is reacted for 1.5 hours and filtered to obtain a decontaminated liquid (i.e., a filtrate) and a decontaminated residue (i.e., a filter residue). The total vanadium content in the filtrate is measured to be 80-90 g / L.

[0084] (3) adding ammonium oxalate at a 2-fold ammonium addition coefficient to the impurity-removing liquid obtained in step (2) to precipitate vanadium to obtain a vanadate product after impurities are removed.

[0085] (4) The impurity-removed residue obtained in step (2) is washed with pure water three times according to L:S=4:1. The washing filtrate can be returned to step (1) for recycling. The vanadium loss is calculated to be 0.5-7%wt.

[0086] After impurities are removed, the arsenic content of the vanadate product is less than 2mg / Kg, the silicon content is less than 30mg / Kg, and the chromium content is less than 15mg / Kg. The ICP test of arsenic, silicon, aluminum, sodium and other impurity ion contents in the vanadium material meets the requirements of all-vanadium liquid flow battery electrolyte.

[0087] Example 4

[0088] Example 4: Using ammonium polyvanadate produced in a certain place in Sichuan as raw material, arsenic was removed by the following method. The basic information of the raw materials used is: ammonium polyvanadate produced in a certain place in Sichuan, and the chemical composition of each kilogram of vanadium raw material is 50-250 mg of arsenic, 150-350 mg of silicon, 100-300 mg of chromium, 600-850 mg of manganese, and other impurities.

[0089] Specific methods for removing arsenic include:

[0090] (1) Take the above solid vanadium material and dissolve it to prepare a vanadium solution. Take 65g of ammonium polyvanadate, add it to 0.5L of pure water, add 20g of potassium hydroxide alkaline reagent, heat it to 90°C, and react for 1h. Filter and cool to obtain an alkaline vanadium-containing solution with a total vanadium content of 95-110g / L (calculated as vanadium pentoxide) and a solution pH of 9.5-11.5.

[0091] (2) The vanadium-containing solution obtained in step (1) is heated to 85° C., 5.25 g of aluminum sulfide is added, and the pH value of the solution is adjusted to 9-10 with carbonic acid or sodium carbonate. The mixture is reacted for 1 hour and filtered to obtain a decontaminated liquid (i.e., a filtrate) and a decontaminated residue (i.e., a filter residue). The total vanadium content in the filtrate is measured to be 90-110 g / L.

[0092] (3) adding ammonium carbonate at a 2-fold ammonium addition coefficient to the impurity-removing liquid obtained in step (2) to precipitate vanadium to obtain a vanadate product after impurities are removed.

[0093] (4) The impurity-removed residue obtained in step (2) is washed with pure water 4 times according to L:S=4:1. The washing filtrate can be returned to step (1) for recycling. The vanadium loss is calculated to be 0.5-5.5%wt.

[0094] After impurities are removed, the arsenic content of the vanadate product is less than 2 mg / Kg, the silicon content is less than 30 mg / Kg, and the chromium and manganese content is less than 15 mg / Kg, which meets the requirements of battery-grade vanadium materials for all-vanadium liquid flow batteries.

[0095] Example 5

[0096] Example 5: Using the leachate of stone coal vanadium mine in the production line of a vanadium plant in Shaanxi as the raw material of vanadium-containing solution, the arsenic therein is removed by the following method. The basic situation of the raw materials used is: the leachate of stone coal vanadium mine in the production line of a vanadium plant in Shaanxi is the raw material of vanadium-containing solution, wherein the arsenic content is 30-50 mg / L, the nickel content is 200-300 mg / L, the chromium content is 450-600 mg / L, the iron content is 5800-6200 mg / L, and other impurities.

[0097] Specific methods for removing arsenic include:

[0098] (1) Take 0.5L of the vanadium leaching solution extracted from the vanadium ore, add sodium chlorate oxidant to convert the vanadium valence of the solution into pentavalent according to the state of the vanadium ore leaching solution, add 25g of calcium hydroxide alkaline reagent, heat to 90°C, react for 1h, and the solution pH = 9.5-11.5.

[0099] (2) The vanadium-containing solution obtained in step (1) is heated to 90° C., 5.5 g of sodium aluminate is added, and the pH value of the solution is adjusted to 8-9 with oxalic acid or potassium carbonate. The mixture is reacted for 1 hour and filtered to obtain a decontaminated liquid (i.e., a filtrate) and a decontaminated residue (i.e., a filter residue). The total vanadium content in the filtrate is measured to be 90-110 g / L.

[0100] (3) adding ammonium oxalate at a rate of 2.5 times the ammonium addition coefficient to the impurity-removing liquid obtained in step (2), and precipitating vanadium to obtain a vanadate product after impurity removal.

[0101] (4) The impurity-removed residue obtained in step (2) is washed with pure water 4 times according to L:S=3:1. The washing filtrate can be returned to step (1) for recycling. The vanadium loss is calculated to be 1-6%wt.

[0102] After calculation, it is found that the arsenic content in the vanadate product after impurity removal is less than 2 mg / Kg, the nickel content is less than 2 mg / Kg, the chromium content is 15 mg / L, and the iron content is less than 150 mg / Kg, which meets the requirements of battery-grade vanadium materials for all-vanadium liquid flow batteries.

[0103] 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.

[0104] 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 arsenic from a vanadium-containing solution, characterized in that: include: (1) providing a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5; (2) mixing the vanadium-containing solution and the impurity remover described in step (1), adjusting the pH of the mixed solution to 6.0-9.0, reacting for 0.5-2.5 hours, and filtering to obtain an impurity-removing liquid and impurity-removing residue; (3) subjecting the impurity removal solution obtained in step (2) to vanadium precipitation to obtain vanadate; (4) The impurity-removed residue obtained in step (2) is dissolved by a dissolving solution, and the obtained solution is recovered to step (1) for recycling.

2. The method according to claim 1, characterized in that Step (1) further comprises: if the valence of vanadium in the vanadium-containing solution is lower than 5, the vanadium-containing solution is subjected to oxidation pretreatment in advance, and the valence of vanadium in the vanadium-containing solution after the oxidation pretreatment is 5.

3. The method according to claim 1, characterized in that The vanadium-containing solution is selected from at least one of a vanadium extraction leaching solution, a vanadium extraction enrichment solution, and a solid vanadium dissolving solution.

4. The method according to claim 3, characterized in that The solid vanadium solution is a vanadium-containing solution prepared by dissolving a vanadium-containing raw material in an alkaline solution, and the alkaline solution is selected from at least one of sodium bicarbonate, sodium percarbonate, sodium carbonate, calcium carbonate, ammonium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and calcium hydroxide.

5. The method according to claim 1, characterized in that Step (2) further comprises: heating the vanadium-containing solution described in step (1) to a temperature not exceeding 90 degrees Celsius, mixing it with an impurity remover and polyacrylamide, adjusting the pH of the mixed solution to 6.0-9.0, reacting for 0.5-2.5 hours, and filtering to obtain an impurity-removing liquid and impurity-removing residue.

6. The method according to claim 1, characterized in that In the step (2), the impurity remover is selected from at least one of sodium sulfide, sodium phosphate, aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum silicate, aluminum phosphate, aluminum titanate, aluminum sulfide, sodium aluminate, alum, ethyl aluminum phosphate, activated alumina, aluminum nitride, aluminum glycolate, aluminum carbide, aluminum hydroxide, lanthanum aluminum oxide, sodium aluminosilicate, sodium aluminosilicate, vanadium aluminum carbide, and titanium aluminum carbide; The dosage of the impurity remover is 1-8w% of the mass of the vanadium-containing solution.

7. The method according to claim 1, characterized in that In step (4), the dissolving liquid is at least one of pure water, ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium oxalate, ammonium acetate, sodium carbonate, sodium hydroxide, and sodium bicarbonate; The mass concentration of the dissolving solution in step (4) is 0 to 10 wt %.

8. A device for removing arsenic from a vanadium-containing solution, characterized in that: include: A raw material supply unit, the raw material supply unit is used to provide a vanadium-containing solution, wherein the valence state of vanadium in the vanadium-containing solution is 5; An impurity removal unit, the impurity removal unit is connected to the raw material supply unit, and is used to mix the vanadium-containing solution and the impurity removal agent, adjust the pH of the mixed solution to 6.0-9.0, react for 0.5-2.5 hours, and filter to obtain an impurity removal liquid and impurity removal residue; A precipitation unit, the precipitation unit is connected to the impurity removal unit, and the precipitation unit is used to treat the impurity removal liquid and reverse vanadium precipitation to obtain vanadate; A dissolving unit is connected to the impurity removal unit and the raw material supply unit. The dissolving unit performs solution treatment on the impurity removal residue by means of a dissolving liquid, and the obtained solution is recovered to the raw material supply unit for recycling.

9. The device according to claim 8, characterized in that The raw material supply unit further comprises: if the valence of vanadium in the vanadium-containing solution is lower than 5, performing oxidation pretreatment on the vanadium-containing solution in advance, and the valence of vanadium in the vanadium-containing solution after the oxidation pretreatment is 5.

10. The device according to claim 8, characterized in that The vanadium-containing solution is selected from at least one of a vanadium extraction leaching solution, a vanadium extraction enrichment solution, and a solid vanadium dissolving solution.

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