Method for preparing VOSO4 electrolyte through gas enhanced reduction and reverse extraction

Abstract

The invention provides a method for preparing VOSO4 electrolyte through gas enhanced reduction and reverse extraction, which comprises the following steps: adding an extraction inhibitor into an acidic vanadium-containing solution, stirring and reacting to obtain a vanadium-containing solution, the extraction inhibitor being phosphoric acid and / or a phosphoric acid compound; adjusting the pH value of the solution to 0.5-3.0 by using sulfuric acid, mixing with an organic phase, extracting, and separating liquid to obtain a vanadium-loaded organic phase; washing the vanadium-loaded organic phase with dilute sulfuric acid; a stripping agent and the vanadium-loaded organic phase are mixed for stripping, meanwhile, gas is introduced for strengthening the stripping process, and a no-load organic phase and a vanadium electrolyte are obtained; and the vanadium strip liquor is subjected to galvanic pile electrolysis adjustment, and the vanadium electrolyte with the valence state meeting the standard is obtained. The invention provides a novel process for directly preparing the vanadyl sulfate electrolyte through gas reinforced reduction, and the novel process has the advantages of being simple in process, easy to operate, low in cost and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to a vanadium electrolyte energy storage technology for all-vanadium liquid flow batteries, in particular to a method for preparing VOSO by gas-enhanced reduction stripping. 4 Electrolyte method. Background Art

[0002] All-vanadium liquid flow batteries, with their high energy conversion efficiency, long service life, adjustable capacity, safety and environmental friendliness, can effectively solve the intermittent and instability problems of renewable energy, improve the stability and reliability of the power system, and become the preferred technology for large-scale energy storage such as wind power, solar power and electricity peak shaving. In addition, all-vanadium liquid flow batteries have broad application prospects in emergency power supply, municipal transportation, military power storage, communication base stations and other fields.

[0003] Compared with other chemical batteries, the Vanadium Redox Flow Battery (VanadiumRFB) is a redox flow battery based on the reversible conversion of vanadium ions between different oxidation states. 2+ (II) and V 3+ (III), V 4+ (IV) and V 5+ (V), etc. The battery uses the reversible change of vanadium ions between different oxidation states to store and release energy. In addition, the positive and negative active materials of the all-vanadium liquid flow battery are stored in two different tanks respectively. During the charging and discharging process, an external infusion pump is used to push the electrolyte through the positive and negative electrodes respectively, realizing the separation of charging (energy storage) and discharging (electrical energy release). This allows the energy density and power density of the battery to be independently optimized and controlled and has good scalability. The most core component is the vanadyl sulfate electrolyte. Therefore, the discharge performance, discharge efficiency and energy efficiency of the all-vanadium liquid flow battery system depend on the composition and performance of the vanadium electrolyte. Up to now, there are three main methods for preparing the electrolyte of the all-vanadium liquid flow battery: physical dissolution method, chemical reduction method and extraction electrolysis method.

[0004] The physical dissolution method is to prepare high-purity ammonium metavanadate from vanadium-containing raw materials, and then use a rotary kiln to reduce and roast the ammonium metavanadate into V 2 O 4 and V 2 O 3 Finally, V 2 O 4 and V 2 O 3The vanadium energy storage medium is obtained by dissolving it in sulfuric acid solution and adjusting it later. The advantages of this method are mature technology and high stability of the prepared product, but the process is long and cumbersome, and the production process produces a large amount of ammonia nitrogen wastewater, high energy consumption and high cost. The chemical reduction method uses low-valent sulfur, oxalic acid or organic carboxylic acid, alcohol and other chemical substances as reducing agents to prepare V containing vanadium raw materials under high temperature conditions. 2 O 5 Or the high-valent vanadium in vanadate is reduced to trivalent or tetravalent to prepare vanadium energy storage medium. Because this method introduces organic matter, the final vanadium electrolyte prepared has poor stability, is prone to crystallization and precipitation, and has a narrow temperature applicability.

[0005] The extraction electrolysis method generally uses pentavalent vanadium purified liquid as raw material. Due to different extractants, the process flow is also different. The process flow of using phosphate cation extractants represented by P507 and P204 is pentavalent vanadium qualified liquid, using sulfuric acid to adjust the solution pH to 2.0-3.0, then adding a reducing agent to reduce it to tetravalent, then extracting and enriching, and sulfuric acid stripping to obtain vanadium oxysulfate solution, and then adjusting by electrolysis to prepare vanadium electrolyte. This process has the problem of large amount of reducing agent, low utilization rate, and the raffinate wastewater generated in the extraction process cannot be recycled. The process flow of using organic amine anion extractants represented by N235 and N1923 is pentavalent vanadium qualified liquid, using sulfuric acid to adjust the solution pH to 1.0-2.0, then extracting and enriching, sodium carbonate stripping to obtain sodium vanadate solution, adding ammonia water or ammonium sulfate to prepare ammonium metavanadate solid, and then preparing vanadium oxysulfate solution through solid roasting, reduction, and dissolution, and then adjusting by electrolysis to prepare vanadium electrolyte. Although the extraction wastewater can be recycled in this process, ammonia nitrogen wastewater will be produced, and there are disadvantages such as solid-liquid phase change, large amount of acid and alkali, complicated operation, long process flow and high cost. Summary of the invention

[0006] The purpose of the present invention is to propose a method for preparing VOSO by gas-enhanced reduction stripping in view of the above problems. 4 The method provides a new process for directly preparing vanadium sulfate electrolyte by gas-enhanced reduction, which can not only solve the problem that the organic amine extractant in the existing process cannot be used for high-concentration acid stripping to prepare VOSO 4 It not only solves the problem of pollution, but also has the advantages of simple process, easy operation, low cost and green environmental protection.

[0007] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a gas-enhanced reduction stripping method for preparing VOSO4 The method of preparing an electrolyte comprises the following steps:

[0009] Step 1: adding an extraction inhibitor to an acidic vanadium-containing solution, stirring and reacting to obtain a vanadium-containing solution, wherein the extraction inhibitor is phosphoric acid and / or a phosphoric acid compound;

[0010] Step 2: Extraction, using sulfuric acid to adjust the pH of the vanadium-containing solution to 0.5-3.0, mixing with the organic phase for extraction and then separating to obtain a vanadium-loaded organic phase;

[0011] Step 3: washing, using dilute sulfuric acid to wash the vanadium-loaded organic phase to elute metal impurities such as Na, K, Ca, and Mn that are easily entrained;

[0012] Step 4: stripping, mixing a stripping agent with the vanadium-loaded organic phase for stripping, while introducing gas to strengthen the stripping process, to obtain an empty organic phase and a vanadium stripping solution;

[0013] Step 5: Adjustment: After the vanadium stripping solution is obtained, the valence state is adjusted by stack electrolysis (the valence state of vanadium is adjusted to 3.5 by stack electrolysis) to obtain a vanadium electrolyte with a valence state that meets the standard.

[0014] Furthermore, the acidic vanadium-containing solution in step 1 is obtained by acid leaching the tailings of vanadium-titanium magnetite ironmaking or stone coal ore, and the vanadium slag after calcification roasting by sulfuric acid. Before adding the extraction inhibitor, the acidic vanadium-containing solution in step 1 is subjected to impurity removal. The impurity removal includes but is not limited to oxidizing manganese from divalent to trivalent by adding a strong oxidant (such as potassium permanganate), and the trivalent manganese ions undergo a disproportionation reaction to become MnO 2 The precipitate was removed by filtration.

[0015] Furthermore, the pH value of the acidic vanadium-containing solution in step 1 is 1.0 to 3.0, and the pH value is preferably 2.0 to 3.0.

[0016] Furthermore, the vanadium concentration (in V) in the acidic vanadium-containing solution in step 1 is 2 O 5 The total amount is 5g / L~55g / L.

[0017] Furthermore, the iron concentration in the acidic vanadium-containing solution in step 1 is 0.05 g / L to 0.5 g / L.

[0018] Furthermore, the aluminum concentration in the acidic vanadium-containing solution in step 1 is 0.1 g / L to 3 g / L.

[0019] Furthermore, the chromium concentration in the acidic vanadium-containing solution in step 1 is 0.1 g / L to 1 g / L.

[0020] Furthermore, the silicon concentration in the acidic vanadium-containing solution in step 1 is 0.1 g to 2 g / L.

[0021] Furthermore, the manganese concentration in the acidic vanadium-containing solution in step 1 is 0.1 g to 3 g / L.

[0022] Furthermore, the zinc concentration in the acidic vanadium-containing solution in step 1 is 0.1 g / L to 2 g / L.

[0023] Furthermore, the titanium concentration in the acidic vanadium-containing solution in step 1 is 0.05 g / L to 0.5 g / L.

[0024] Furthermore, in step 1, the extraction inhibitor is one or more of phosphoric acid, trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, diammonium hydrogen phosphate and ammonium dihydrogen phosphate, and the extraction inhibitor can release phosphate ions. The extraction inhibitor is preferably phosphoric acid, because when phosphoric acid is used as the extraction inhibitor, impurities such as sodium and ammonium are not introduced into the solution.

[0025] The extraction inhibitor of the present invention has two functions: first, it can inhibit the co-extraction process of three metal impurities, iron, chromium and titanium, during the extraction process; second, it can improve the stability of the vanadium-containing solution when the pH value is less than or equal to 2.0.

[0026] Furthermore, the amount of the extraction inhibitor added is 0.02 mol / L to 0.05 mol / L (acidic vanadium-containing solution) in terms of phosphorus molar amount.

[0027] Furthermore, the stirring speed in step 1 is 200 rpm to 500 rpm.

[0028] Furthermore, the stirring reaction (extraction inhibitor reaction) time of step 1 is 0.5h to 2.0h, and then standing for 4h to 20h. The reaction is carried out at room temperature without the need for an external heat source.

[0029] a. When the reaction time of the extraction inhibitor is 4h to 6h, the subsequent extraction process will 3+ The co-extraction inhibition effect of

[0030] b. When the reaction time of the extraction inhibitor is 4h to 16h, the subsequent extraction process will 3+ The co-extraction inhibition effect of

[0031] c. When the reaction time of the extraction inhibitor is 6h to 10h, the subsequent extraction process will 4+ The co-extraction inhibition was the best.

[0032] Furthermore, the extracted organic phase in step 2 includes an organic extractant, a cosolvent and an organic diluent, wherein the volume percentage of the organic extractant is 1% to 15%, the volume percentage of the cosolvent is 5% to 10%, and the volume percentage of the organic diluent is 75% to 94%. The organic extractant is an organic amine extractant, including but not limited to trioctylamine (N235); the cosolvent is a multi-chain alcohol, which is one of tributyl phosphate (TBP), n-octanol and sec-octanol; and the organic diluent is sulfonated kerosene.

[0033] Furthermore, the volume ratio of the extracted organic phase to the vanadium-containing solution in step 2 is O:A=0.2-5:1.

[0034] Furthermore, in step 2, the extraction stirring speed is 500 rpm to 800 rpm, the stirring temperature is 20° C. to 60° C., and the stirring time is 3 to 15 min.

[0035] Furthermore, in step 2, sulfuric acid is used to adjust the pH of the solution to 0.5 to 3.0, preferably 1.0 to 2.0, and the sulfuric acid concentration is 94% to 98% concentrated sulfuric acid.

[0036] Furthermore, the concentration of dilute sulfuric acid in step 3 is 0.05 mol / L to 0.1 mol / L, and the washing conditions are: mixing the vanadium-loaded organic phase with dilute sulfuric acid in a volume ratio of O / A=10 to 20:1, the number of countercurrent washing stages is 1 to 4, the washing temperature is 20°C to 50°C, and the single-stage washing time is 3min to 10min.

[0037] Further, the stripping agent in step 4 is V 3+ Concentration 0.8mol / L~1.2mol / L, SO 4 2- Aqueous solution or SO with a concentration of 3.8 mol / L to 4.5 mol / L 4 2- The concentration of SO is 3.5mol / L to 4.2mol / L and the concentration of sulfurous acid is 0.2mol / L to 0.6mol / L. 4 2- The aqueous solution with a concentration of 3.5mol / L to 4.2mol / L and a sulfurous acid concentration of 0.2mol / L to 0.6mol / L is made of SO 2 It is prepared by passing the gas into a sulfuric acid solution.

[0038] Furthermore, in step 4, when the stripping agent is mixed with the vanadium-loaded organic phase for stripping, SO can also be introduced into the stripping agent. 2 Gas, SO 2 The gas can act as a reducing agent, and together with the hydrogen ions, it reduces pentavalent vanadium to tetravalent vanadium, and converts sulfur dioxide into sulfate.

[0039] Furthermore, the volume ratio of the stripping agent in step 4 to the vanadium-loaded organic phase is O / A=1 to 10:1.

[0040] Furthermore, the stripping stage number in step 4 is 2 to 6, the stripping temperature is 20° C. to 60° C., and the single-stage stripping time is 5 min to 20 min.

[0041] Furthermore, the gas introduced in step 4 is one or more of carbon dioxide, oxygen, nitrogen, air and argon.

[0042] Furthermore, in step 4, the gas is dispersed by a gas disperser or a gas dispersion disk, and the gas flow rate is 100-500 mL / min·L (oil-water mixture), that is, the gas flow rate per 1L liquid volume (organic phase volume plus water phase volume) is 100-500 mL / min.

[0043] Furthermore, the vanadium concentration (in V) in the vanadium electrolyte in step 5 is 2 O 5 The total amount is 145g / L-155g / L.

[0044] Furthermore, the iron concentration in the vanadium electrolyte in step 5 is ≤0.035 g / L.

[0045] Furthermore, the aluminum concentration in the vanadium electrolyte in step 5 is ≤0.035 g / L.

[0046] Furthermore, the chromium concentration in the vanadium electrolyte in step 5 is ≤0.005 g / L.

[0047] Furthermore, the silicon concentration in the vanadium electrolyte in step 5 is ≤0.010 g / L.

[0048] Furthermore, the manganese concentration in the vanadium electrolyte in step 5 is ≤0.005 g / L.

[0049] Furthermore, the zinc concentration in the vanadium electrolyte in step 5 is ≤0.005 g / L.

[0050] Furthermore, the titanium concentration in the vanadium electrolyte in step 5 is ≤0.010 g / L.

[0051] Preparation of VOSO by gas-enhanced reduction stripping 4 The electrolyte method has the following advantages compared with the prior art:

[0052] 1) The present invention can enhance the interfacial reaction by introducing gas during stripping, so that the reduction reaction can occur smoothly, convert pentavalent vanadium into tetravalent vanadium, and transfer vanadium from the organic phase to the aqueous phase. The defect that amine anion extractants can only be stripped with alkali is solved; the problem that the organic phase is abnormally separated and the organic phase cannot be regenerated during the stripping process of amine anion extractants using high concentration acids (sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, etc.) is solved.

[0053] 2) The present invention uses an organic amine extractant N235 to extract V 5+ The process technology of extracting vanadium from vanadium purification solution by extractant and gas reduction stripping directly prepares vanadyl sulfate electrolyte. Its raw material cost is much lower than that of APV, AMV or high purity V 2 O 5 The vanadium electrolyte is prepared by using the raw material, which significantly reduces the cost of preparing the electrolyte from the acidic vanadium-containing leaching solution and reduces the total cost by more than about 20%.

[0054] 3) Compared with traditional VOSO 4 The preparation process has the advantages of easy operation, short process, extremely low organic phase loss in the whole process, and the organic phase after stripping can be directly used for the next extraction, the raffinate is directly stripped and leached in the pH adjustment stage, and there is no wastewater discharge, etc. It is easy to be applied on a large scale in large-scale production such as extraction machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Preparation of VOSO by gas-enhanced reduction stripping 4 Process flow diagram of the electrolyte method. DETAILED DESCRIPTION

[0056] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0057] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0058] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0059] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0060] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0061] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0062] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0063] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0064] Unless otherwise specified, % in the present invention refers to mass percentage.

[0065] Embodiment 1:

[0066] This embodiment discloses a method for preparing VOSO by gas-enhanced reduction stripping 4 The method comprises the following steps: using a vanadium purified solution as a vanadium extraction stock solution, wherein V 2 O 5 The concentration (equivalent concentration) is 52.14 g / L, and the pH value of the solution is between 2.5 and 3.0. The composition of the vanadium purification solution is shown in Table 1:

[0067] Table 1 Example 1 Vanadium purification liquid composition

[0068] project <![CDATA[V 2 O 5 (g / L)]]> Fe(g / L) Al(g / L) Cr(g / L) Si(g / L) Mn(g / L) Zn(g / L) Ti(g / L) concentration 52.14 0.045 0.206 0.017 0.832 0.345 0.278 0.018

[0069] Use 1 mol / L dilute sulfuric acid to acidify an equal volume of N235 to obtain acidified N235. Prepare 200 mL of acidified N235 extractant with a composition of 5% N235 + 90% No. 260 solvent oil + 5% sec-octanol according to the volume ratio. 3+ 60 mL of an aqueous solution with a concentration of 0.98 mol / L and a sulfate concentration of 4.22 mol / L is used as a stripping agent.

[0070] The gas-enhanced reduction stripping method for preparing VOSO in this embodiment 4 Electrolyte methods, such as Figure 1 As shown, the specific steps include:

[0071] Step 1: Add 0.006 mol phosphoric acid to 200 mL of vanadium purification solution, stir for 5 minutes, let stand for 6 hours, and then use concentrated sulfuric acid to adjust the pH value of the vanadium purification solution to 1.47 to obtain a vanadium pre-extraction solution.

[0072] Step 2: Mix the prepared acidified N235 extractant with the vanadium pre-extraction solution, at a phase ratio of O / A = 200:200 = 1:1, stir in a 50°C water bath at a stirring speed of 800 rpm for 5 minutes to extract vanadium, and separate the phases to obtain a vanadium-loaded organic phase and a raffinate.

[0073] Step 3: The organic phase loaded with vanadium was washed three times in countercurrent with 0.1 mol / L dilute sulfuric acid with a phase ratio of O / A = 20:1. The washing water bath temperature was 50° C., the stirring speed was 400 rpm, and the single-stage washing time was 5 min.

[0074] Step 4: Using the above stripping solution, compared with O / A = 10:1, CO 2 The vanadium was stripped in three stages at a gas velocity of 100 mL / min, the stripping temperature was 60 °C, the stirring speed was 600 rpm, and the single-stage stripping time was 20 min. After phase separation, V 2 O 5 The concentration is 268.64 g / L vanadium stripping solution and regenerated organic phase.

[0075] After testing: the vanadium recovery rate is 98.75%, the iron content in the stripping liquid product is 0.019g / L, the aluminum content is 0.005g / L, the chromium concentration is 0.004g / L, the manganese content is 0.006g / L, the zinc content is 0.001g / L, and the titanium content is 0.009g / L.

[0076] Step 5: After passing through the resin and activated carbon tower, the vanadium stripping solution is electrolyzed to obtain a vanadium electrolyte with a valence (3.5) that meets the specifications.

[0077] Embodiment 2:

[0078] This embodiment discloses a method for preparing VOSO by gas-enhanced reduction stripping 4 The method comprises the following steps: using a vanadium purified solution as a vanadium extraction stock solution, wherein V 2 O 5 The concentration (equivalent concentration) is 23.85 g / L, and the pH value of the solution is between 2.5 and 3.0. The composition of the vanadium purification solution is shown in Table 2:

[0079] Table 2 Example 2 Vanadium purification liquid composition

[0080] project <![CDATA[V 2 O 5 (g / L)]]> Fe(g / L) Al(g / L) Cr(g / L) Si(g / L) Mn(g / L) Zn(g / L) Ti(g / L) concentration 23.85 0.029 0.263 0.011 0.671 0.311 0.260 0.005

[0081] Use 1 mol / L dilute sulfuric acid to acidify an equal volume of N235 to obtain acidified N235. Prepare 200 mL of acidified N235 extractant with a composition of 5% N235 + 90% No. 260 solvent oil + 5% sec-octanol according to the volume ratio. 3+ 60 mL of an aqueous solution with a concentration of 1.0 mol / L and a sulfate concentration of 4.32 mol / L was used as a stripping reagent.

[0082] The gas-enhanced reduction stripping method for preparing VOSO in this embodiment 4 The method of the electrolyte comprises the following steps:

[0083] Step 1: Add 0.006 mol phosphoric acid to 200 mL of vanadium purification solution, stir for 5 minutes, let stand for 6 hours, and then use concentrated sulfuric acid to adjust the pH value of the vanadium purification solution to 1.48 to obtain a vanadium pre-extraction solution.

[0084] Step 2: Mix the prepared acidified N235 extractant with the vanadium pre-extraction solution, at a phase ratio of O / A = 200:200 = 1:1, stir in a 50°C water bath at a stirring speed of 800 rpm for 5 minutes to extract vanadium, and separate the phases to obtain a vanadium-loaded organic phase and a raffinate.

[0085] Step 3: The organic phase loaded with vanadium was washed three times in countercurrent with 0.1 mol / L dilute sulfuric acid with a phase ratio of O / A = 20:1. The washing water bath temperature was 50° C., the stirring speed was 400 rpm, and the single-stage washing time was 5 min.

[0086] Step 4: Using the above stripping solution, compared with O / A = 10:1, CO 2 The vanadium was stripped in three stages at a gas velocity of 100 mL / min, the stripping temperature was 60 °C, the stirring speed was 600 rpm, and the single-stage stripping time was 20 min. After phase separation, V 2 O 5 The concentration is 206.75g / L vanadium stripping solution and regenerated organic phase.

[0087] After testing: the vanadium recovery rate is 98.39%, the iron content in the stripping liquid product is 0.021g / L, the aluminum content is 0.006g / L, the chromium concentration is 0.002g / L, the manganese content is 0.006g / L, the zinc content is 0.0007g / L, and the titanium content is 0.004g / L.

[0088] Step 5: After passing through the resin and activated carbon tower, the vanadium stripping solution is electrolyzed to obtain a vanadium electrolyte with a valence (3.5) that meets the specifications.

[0089] Embodiment 3:

[0090] This embodiment discloses a method for preparing VOSO by gas-enhanced reduction stripping 4 The method comprises the following steps: using a vanadium purified solution as a vanadium extraction stock solution, wherein V 2 O 5 The concentration (equivalent concentration) is 23.85 g / L, and the solution pH is between 2.5 and 3.0. The composition of the vanadium purification solution is shown in Table 3:

[0091] Table 3 Example 3 Vanadium purification liquid composition

[0092] project <![CDATA[V 2 O 5 (g / L)]]> Fe(g / L) Al(g / L) Cr(g / L) Si(g / L) Mn(g / L) Zn(g / L) Ti(g / L) concentration 20.63 0.021 0.144 0.018 0.159 0.595 0.018 0.014

[0093] Use 1 mol / L dilute sulfuric acid to acidify an equal volume of N235 to obtain acidified N235. Prepare 200 mL of acidified N235 extractant with a composition of 5% N235 + 90% No. 260 solvent oil + 5% sec-octanol according to the volume ratio. 3+ 60 mL of an aqueous solution with a concentration of 1.18 mol / L and a sulfate concentration of 4.51 mol / L was used as a stripping reagent.

[0094] The gas-enhanced reduction stripping method for preparing VOSO in this embodiment 4 The method of the electrolyte comprises the following steps:

[0095] Step 1: Add 0.006 mol phosphoric acid to 200 mL of vanadium purification solution, stir for 5 minutes, let stand for 6 hours, and then use concentrated sulfuric acid to adjust the pH value of the vanadium purification solution to 2.08 to obtain a vanadium pre-extraction solution.

[0096] Step 2: Mix the prepared acidified N235 extractant with the vanadium pre-extraction solution, at a phase ratio of O / A = 200:200 = 1:1, stir in a 50°C water bath at a stirring speed of 800 rpm for 5 minutes to extract vanadium, and separate the phases to obtain a vanadium-loaded organic phase and a raffinate.

[0097] Step 3: using a phase ratio of O / A = 20:1, 0.08 mol / L dilute sulfuric acid to perform three-stage countercurrent washing of the vanadium-loaded organic phase, the washing water bath temperature is 40° C., the stirring speed is 400 rpm, and the single-stage washing time is 5 min.

[0098] Step 4: Using the above stripping solution, the ratio O / A=8:1, the air gas velocity is 100mL / min, the stripping temperature is 60°C, the stirring speed is 800rpm, the single-stage stripping time is 20min, and V is obtained after phase separation. 2 O 5 The concentration is 238.72 g / L vanadium stripping solution and regenerated organic phase.

[0099] After testing: the vanadium recovery rate is 98.15%, the iron content in the stripping liquid product is 0.011g / L, the aluminum content is 0.006g / L, the chromium concentration is 0.005g / L, the manganese content is 0.004g / L, the zinc content is 0.0004g / L, and the titanium content is 0.008g / L.

[0100] Step 5: After passing through the resin and activated carbon tower, the vanadium stripping solution is electrolyzed to obtain a vanadium electrolyte with a valence (3.5) that meets the specifications.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping, characterized in that: The following steps are involved: Step 1: adding an extraction inhibitor to an acidic vanadium-containing solution, stirring and reacting to obtain a vanadium-containing solution, wherein the extraction inhibitor is phosphoric acid and / or a phosphoric acid compound; Step 2: Extraction, using sulfuric acid to adjust the solution pH to 0.5-3.0, and then mixing with the extracted organic phase for extraction and separation to obtain a vanadium-loaded organic phase; Step 3: washing, using dilute sulfuric acid to wash the vanadium-loaded organic phase; Step 4: stripping, mixing a stripping agent with the vanadium-loaded organic phase for stripping, while introducing gas to strengthen the stripping process, to obtain an empty organic phase and a vanadium stripping solution; Step 5: Adjustment: After the vanadium stripping solution is obtained, the valence state is adjusted by stack electrolysis to obtain a vanadium electrolyte with a valence state that meets the standard.

2. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The pH value of the acidic vanadium-containing solution in step 1 is 1.0 to 3.

0.

3. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The acidic vanadium-containing solution has a vanadium concentration of 5 to 55 g / L, and / or an iron concentration of 0.05 g / L to 0.5 g / L, and / or an aluminum concentration of 0.1 g / L to 3 g / L, and / or a chromium concentration of 0.1 g / L to 1 g / L, a silicon concentration of 0.1 g to 2 g / L, and / or a manganese concentration of 0.1 g to 3 g / L, and / or a zinc concentration of 0.1 g / L to 2 g / L, and / or a titanium concentration of 0.05 g / L to 0.5 g / L.

4. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The extraction inhibitor in step 1 is one or more of phosphoric acid, trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, diammonium hydrogen phosphate and ammonium dihydrogen phosphate.

5. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1 or 4, characterized in that: The amount of the extraction inhibitor added is 0.02 mol / L to 0.05 mol / L in terms of phosphorus molar amount.

6. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The extracted organic phase in step 2 comprises an organic extractant, a cosolvent and an organic diluent, wherein the organic extractant is an organic amine extractant; the cosolvent is a multi-chain alcohol; and the organic diluent is sulfonated kerosene; And / or, the volume ratio of the extracted organic phase to the vanadium-containing solution is O:A=0.2-5:

1.

7. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The concentration of the dilute sulfuric acid in step 3 is 0.05 mol / L to 0.1 mol / L.

8. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The stripping agent in step 4 is V 3+ Concentration 0.8~1.2mol / L, SO4 2- Aqueous solution or SO4 with a concentration of 3.8 to 4.5 mol / L 2- An aqueous solution with a concentration of 3.5-4.2 mol / L and a sulfurous acid concentration of 0.2-0.6 mol / L; And / or, the volume ratio of the stripping agent to the vanadium-loaded organic phase is O / A=1-10:

1.

9. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1, characterized in that: The gas introduced in step 4 is one or more of carbon dioxide, oxygen, nitrogen, air and argon.

10. The method for preparing VOSO4 electrolyte by gas-enhanced reduction stripping according to claim 1 or 9, characterized in that: In step 4, the gas inlet flow rate is 100 mL / min·L to 500 mL / min·L.

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