Solid-liquid full-utilization short-process vanadium battery electrolyte production process

Abstract

The invention provides a solid-liquid full-utilization short-process vanadium battery electrolyte production process, which comprises the following steps: mixing high-purity vanadium, sulfuric acid and a cosolvent in an activation reaction tank, activating at high temperature, and cooling; enabling the mixed solution subjected to high-temperature activation to enter a jacketed cooling tank, cooling, enabling the cooled mixed solution to enter a dissolution reaction tank, injecting desalted water into the dissolution reaction tank, dissolving the desalted water, the V < 5 + > mixed solution and a secondary dissolution solution from a filter residue dissolution tank, and filtering to obtain a pentavalent vanadium electrolyte; the vanadium electrolyte is added to the cathode side of the diaphragm electrolytic tank, a sulfuric acid solution is added to the anode side of the diaphragm electrolytic tank, electrolytic reduction is carried out under the constant current condition, the electrolyte subjected to secondary valence adjustment is a finished electrolyte, and the finished electrolyte enters a filling procedure for finished product filling; first filter residues generated by the filter and second filter residues generated by the sludge dewatering machine are subjected to reduction dissolution in the filter residue dissolution tank through trivalent vanadium electrolyte refluxed by the liquid outlet tank, and secondary dissolution liquid obtained after dissolution enters the dissolution reaction tank, so that closed circulation with full solid-liquid utilization is formed.

Description

Technical Field

[0001] The invention relates to the technical field of all-vanadium liquid flow electrolyte, and in particular to a short-process vanadium battery electrolyte production process with full solid-liquid utilization. Background Art

[0002] The all-vanadium liquid flow battery energy storage system is mainly composed of electrolyte, battery stack, battery management system and auxiliary system. It is widely used in off-grid and grid-connected energy storage systems due to its high safety, slow energy decay and recyclable electrolyte. The electrolyte accounts for about half of the production cost of the entire system. Therefore, how to maximize the utilization rate of vanadium is the difficulty of the current vanadium electrolyte industry.

[0003] At present, electrolyte production mainly uses ammonium metavanadate, vanadium pentoxide and vanadyl sulfate as raw materials, and obtains the required target electrolyte through chemical reduction, electrolytic reduction, physical dissolution and other methods. Vanadyl sulfate produces vanadium electrolyte without vanadium-containing filter residue, but its high price hinders its industrial production. Ammonium metavanadate is essentially a hydrate of vanadium pentoxide. The vanadium-containing filter residue produced by both in the electrolyte production process will increase the production cost of vanadium electrolyte. Therefore, the full solid and liquid utilization of vanadium raw materials is a powerful way to reduce the cost and increase the efficiency of vanadium electrolyte.

[0004] CN118073620A discloses a method for producing electrolyte for all-vanadium liquid flow battery, wherein vanadium pentoxide is added to acid solution to dissolve, and a reducing agent is added to promote dissolution to generate vanadium turbid liquid, and then the vanadium turbid liquid is filtered and separated, and a reducing agent and pure water are added to perform reduction reaction to generate raw material liquid; after the raw material liquid is cooled and filtered, it is respectively sent to the positive electrode and negative electrode of the reduction stack, the total valence state of vanadium in the raw material liquid on the positive electrode side increases to generate an anode plate, and the total valence state of vanadium in the raw material liquid on the negative electrode side decreases to generate an electrolyte. This patent can directly obtain positive electrode liquid and negative electrode liquid, but it is highly dependent on the reducing agent, and the high current when reducing the raw material liquid in the reduction stack will reduce the life of the exchange membrane.

[0005] CN117673423A discloses a method for preparing an electrolyte for an all-vanadium liquid flow battery, wherein an additive and deionized water are added to a vanadium compound and stirred evenly, and then concentrated sulfuric acid is used for sufficient stirring to obtain a mixture of the vanadium compound, deionized water and sulfuric acid, and the mixture is placed in a furnace with an atmosphere to obtain a vanadium roasting product, and the vanadium roasting product is ground, and a sulfuric acid solution is added to the ground vanadium roasting product to obtain an all-vanadium liquid flow battery electrolyte. The patented process is simple and does not have an electrolysis device, but the introduction of a reducing gas for reduction under high temperature conditions of 100 to 400°C will increase production energy consumption, and the reduction product is difficult to control, and is not suitable for large-scale production.

[0006] CN114447386A discloses a method for preparing an electrolyte for an all-vanadium liquid flow battery, wherein a mixture of solid vanadium pentoxide powder and thioacetamide is mixed with concentrated sulfuric acid to form a uniformly dispersed solid solution at 90-120°C, which is used as a negative electrode electrolyte, and a 3.5-valent vanadium ion sulfuric acid solution is obtained at the negative electrode of the electrolytic cell, which is the electrolyte for an all-vanadium liquid flow battery. The patent is simple to operate, but thioacetamide as a reducing agent will produce sulfur dioxide at high temperatures, which requires a special gas purification system, increasing the equipment cost.

[0007] In the prior art, in the process of preparing pentavalent vanadium solution using vanadium pentoxide and ammonium metavanadate as raw materials, the treatment of vanadium-containing filter residue 1 is usually refluxed to the raw material tank, or collected and roasted into vanadium pentoxide. The above method involves the problem of the dissolution speed and difficulty of vanadium-containing filter residue 1 in the pentavalent vanadium electrolyte system. It is not easy to dissolve completely, and the dissolution conditions are harsh, requiring a higher temperature to promote dissolution, or auxiliary solvents to dissolve. At present, most technologies in the process of reducing pentavalent vanadium to tetravalent vanadium use reduction methods such as oxalic acid, glycerol, hydrogen peroxide, formic acid, thiourea, thioacetamide, dodecyl sulfonic acid, and sulfur dioxide, hydrogen sulfide, hydrogen-argon mixed gas under high temperature conditions. Whether it is a liquid reducing agent or a gas reducing agent, it will bring problems of high cost, harmful gas treatment and impurity removal after the introduction of additional impurities.

[0008] There are two main types of electrolytic reduction in the prior art. One is electrolytic reduction in an electrolytic cell, that is, using a 5-valent vanadium solution as the cathode plate and sulfuric acid as the anode plate, and electrolytic reduction to a 3.5-valent finished liquid; the other is to pass the 5-valent vanadium solution into a reduction stack to obtain a positive electrode liquid and a negative electrode liquid respectively. Electrolytic cell reduction involves two electron transfers, and the required electrolysis time is long. If the reduction time needs to be reduced, the current density needs to be increased accordingly. The technical requirements of the stack itself are relatively high, and high current will accelerate the consumption of electrode materials and ion exchange membranes. Summary of the invention

[0009] In order to overcome the problems in the prior art of complex procedures, many impurities in the later stage, and inability to continuously electrolyze, the present invention provides a short-process vanadium battery electrolyte production process with full solid-liquid utilization.

[0010] The technical solution adopted by the present invention is: a short-process vanadium battery electrolyte production process with full solid-liquid utilization, and its innovation lies in: the production process comprises the following steps: S1: Mix high-purity vanadium, sulfuric acid and co-solvent in an activation reaction tank, activate at high temperature and then cool; S2: The mixed liquid after high temperature activation enters the jacketed cooling tank, and after cooling, enters the dissolution reaction tank. At this time, the valence state of vanadium is mainly pentavalent, that is, V 5+ sulfuric acid mixture; S3: inject desalted water into the dissolution reaction tank, dissolve with the V5+ mixed solution and the secondary dissolved solution from the residue dissolution tank, and the electrolyte mainly composed of trivalent electrolyte in the liquid outlet tank flows back to the residue dissolution tank for mixing; forming a mixed solution mainly composed of tetravalent electrolyte, i.e., the secondary dissolved solution; the dissolved tetravalent crude dissolved solution enters the filter; S4: The crude solution in S3 is separated into residue and water in a filter to obtain filtrate 1 and filter residue 1. The filtrate 1 enters a filtrate tank, and the filter residue 1 enters a filter residue dissolution tank; S5: The filtrate tank includes filtrate 1, filtrate 2 from the sludge dewatering machine, and supplemented concentrated sulfuric acid, which are mixed evenly and then enter the primary price adjustment tank; the effluent from the filtrate tank flows into the primary price adjustment tank, and the trivalent electrolyte after electrolytic reduction partially flows back from the effluent tank to the primary price adjustment tank; S6: After the first price adjustment is completed, the part of the electrolyte with a valence of 4 as the main electrolyte in the price adjustment tank system enters the cathode chamber and is supplemented with inert gas to be electrolytically reduced to a valence of 3 as the main electrolyte, i.e., V3+; the other part is electrolytically reduced to an average valence state of vanadium of V3.5+ and then directly enters the secondary price adjustment tank; S7: The trivalent electrolyte in the liquid outlet tank is partially refluxed to the primary price adjustment tank through the pump, and partially refluxed to the residue dissolving tank; the pipeline from the primary price adjustment tank to the secondary price adjustment tank mainly plays the role of electrolyte valence supplement; the additives are supplemented to ensure the high stability of the finished electrolyte; the electrolyte after the secondary price adjustment is the finished electrolyte, which can enter the filling process for finished product filling; the slag in the primary price adjustment tank and the liquid outlet tank enters the sludge dewatering machine, the filtrate 2 after dehydration enters the filtrate tank, and the residue 2 enters the residue dissolving tank; S8: The filter residue 1 produced by the filter and the filter residue 2 produced by the sludge dewatering machine are reduced and dissolved in the filter residue dissolution tank through the trivalent vanadium electrolyte refluxed from the liquid outlet tank. The secondary dissolved liquid after dissolution enters the dissolution reaction tank, forming a closed cycle with full utilization of solid and liquid.

[0011] On this basis, the high-purity vanadium and sulfuric acid in S1 are respectively transported into the activation reaction tank through a powder conveyor and an acid-resistant pump. The purity of the high-purity vanadium is ≥99.5%, the sulfuric acid is 98% industrial-grade acid, the molar ratio of high-purity vanadium to sulfuric acid is between 1:1 and 1:5, the heat source includes steam heating, thermal oil heating, and heat pump heating. The heating activation temperature ranges from 40 to 180°C, the time is 1 to 4 hours, and stirring is provided in the activation reaction tank. The stirring speed is 60 to 180 rpm, and the co-solvent is a sulfur-containing compound.

[0012] On this basis, the jacketed cooling tank in S2 contains the liquid to be cooled, the jacket contains the refrigerant, including one of cooling water, liquid nitrogen, and liquid ammonia, the cooling temperature is 25-30°C, and the cooling tank is equipped with stirring, and the stirring speed is 45-135rpm.

[0013] On this basis, the desalted water quality in S3 requires conductivity ≤ 0.2us / cm, SiO2 ≤ 20ug / L, the volume ratio of the desalted water and the mixed liquid entering the dissolution reaction tank is 2.5:1~5:1, the dissolution reaction tank is provided with stirring, the stirring speed is 120~240rpm, and the reaction time of the dissolution reaction tank is 30~60min. On this basis, the filter is a centrifugal dehydrator, a plate and frame dehydrator, or a screw stack dehydrator; when a centrifugal dehydrator is used, the centrifugal speed is 800-2000rpm; when a plate and frame dehydrator is used, the filtration pressure is 0.6-4.5MPa; when a screw stack dehydrator is used, the frequency of the driving device controlling the screw shaft is 25-50Hz; the moisture content of the filtered residue is 30-70%, and it is sent to the residue dissolution tank through a shaftless screw conveyor or a belt conveyor. On this basis, the filtrate 1 is mainly composed of pentavalent vanadium, i.e. V 5+ ; The filtrate 2 is mainly composed of 3.5-valent and 3-valent, that is, V 3 + and V 3.5+ ; Supplement sulfuric acid to ensure that the sulfate ion concentration in the effluent of the filtrate tank is 4-6M; the filtrate tank is equipped with a stirrer with a stirring speed of 60-180rpm and a residence time of 1-2h; the reflux ratio of the trivalent electrolyte is about 30-60%, the primary price adjustment tank is equipped with a stirrer with a stirring speed of 60-180rpm and a residence time of about 1-2h; the bottom of the primary price adjustment tank is cone-shaped, and a slag discharge device is provided at the bottom of the cone. The slag discharge to the sludge dewatering machine is controlled by a pneumatic or electric regulating valve. The single slag discharge time is 5-15min, and the slag is discharged every 2-4h.

[0014] On this basis, the cathode and anode electrode combinations in the S6 include one of Pt / Pb, Ti mesh / Pb, RuIrTi mesh / RuIrTi mesh, Ti mesh / RuIrTi mesh and graphite carbon / RuIrTi mesh; the current density range of a single group is 50-200 mA / cm 2 The cell voltage range is 3-10V, the sulfuric acid concentration range of the anode plate is 2-6M, and the electrolysis time is 3-8h; the cathode chamber is equipped with stirring, and the stirring speed range is 100-600rpm.

[0015] On this basis, the liquid outlet tank in the S7 is not equipped with stirring, the bottom of the tank is in the shape of a cone bucket, and a slag discharge device is provided at the bottom of the cone bucket. The slag discharge to the sludge dewatering machine is controlled by a pneumatic or electric regulating valve. The single slag discharge time is 5 to 15 minutes, and the slag is discharged once every 8 to 12 hours; the reflux ratio of the reflux liquid to the primary price adjustment tank is about 30 to 60%, and the reflux ratio of the electrolyte refluxed to the filter residue dissolution tank is about 20 to 30%, and the remaining part enters the secondary price adjustment tank; the ingredients of the additive include one or more of phosphoric acid, citric acid, acetic acid, ethylenediaminetetraacetic acid, dodecylbenzenesulfonic acid, and lauric acid prepared in different proportions.

[0016] On this basis, the sludge dewatering machine in S7 is a centrifugal dewatering machine, a plate and frame dewatering machine, or a screw stack dewatering machine.

[0017] On this basis, the filter residue dissolving tank in S8 is provided with stirring, the stirring speed is 60-180 rpm, the filter residue dissolving time is 1-4h, and after dissolution, it is transported to the dissolution reaction tank through an acid-resistant and wear-resistant pump.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention aims at the high energy consumption and harsh reaction conditions of the recycling process of the filter residue produced in the process of producing electrolyte using vanadium pentoxide as raw material. By refluxing low-price vanadium electrolyte, the dissolution rate of the vanadium-containing filter residue at room temperature is accelerated, thereby solving the problem of high energy consumption and achieving the goal of fully utilizing the raw materials and vanadium slag of high-purity vanadium, and effectively reducing the cost of activation, dissolution and full utilization of the electrolyte for producing vanadium from high-purity vanadium.

[0019] (2) In view of the current situation that when pentavalent vanadium is reduced to tetravalent vanadium under reducing agent conditions, the introduction of the reducing agent affects the subsequent electrolyte performance. The present invention uses a low-valent vanadium electrolyte as a reducing agent to reduce the pentavalent vanadium, thereby improving the solubility and avoiding the introduction of new substances.

[0020] (3) The present invention is different from the traditional "two-stage electrolysis + price adjustment", that is, the first-stage electrolysis electrolyzes the valence state of vanadium from 5 to 4, and the second-stage electrolysis electrolyzes the 4-valent electrolyte to 3 / 3.5. The present invention only electrolyzes the 4-valent electrolyte to 3 / 3.5. Because the theoretical electron transfer number is less than or equal to 1, the energy consumption required for electrolysis and the investment cost of the electrolysis device are reduced compared with the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the process flow of the present invention.

[0022] Among them, 10 is the anode plate; 20 is the cathode plate; 30 is the ion exchange membrane. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The present invention discloses a short-process vanadium battery electrolyte production process with full solid-liquid utilization, referring to Figure 1 As shown: The production process includes the following steps: S1: Mix high-purity vanadium, sulfuric acid and co-solvent in an activation reaction tank, activate at high temperature and then cool; S2: The mixed liquid after high temperature activation enters the jacketed cooling tank, and after cooling, enters the dissolution reaction tank. At this time, the valence state of vanadium is mainly pentavalent, that is, V 5+ sulfuric acid mixture; S3: inject desalted water into the dissolution reaction tank, dissolve with the V5+ mixed solution and the secondary dissolved solution from the residue dissolution tank, and the electrolyte mainly composed of trivalent electrolyte in the liquid outlet tank flows back to the residue dissolution tank for mixing; forming a mixed solution mainly composed of tetravalent electrolyte, i.e., the secondary dissolved solution; the dissolved tetravalent crude dissolved solution enters the filter; S4: The crude solution in S3 is separated into residue and water in a filter to obtain filtrate 1 and filter residue 1. The filtrate 1 enters a filtrate tank, and the filter residue 1 enters a filter residue dissolution tank; S5: The filtrate tank includes filtrate 1, filtrate 2 from the sludge dewatering machine, and supplemented concentrated sulfuric acid, which are mixed evenly and then enter the primary price adjustment tank; the effluent from the filtrate tank flows into the primary price adjustment tank, and the trivalent electrolyte after electrolytic reduction partially flows back from the effluent tank to the primary price adjustment tank; S6: After the first price adjustment is completed, the part of the electrolyte with a valence of 4 as the main electrolyte in the price adjustment tank system enters the cathode chamber and is supplemented with inert gas to be electrolytically reduced to a valence of 3 as the main electrolyte, i.e., V3+; the other part is electrolytically reduced to an average valence state of vanadium of V3.5+ and then directly enters the secondary price adjustment tank; S7: The trivalent electrolyte in the liquid outlet tank is partially refluxed to the primary price adjustment tank through the pump, and partially refluxed to the residue dissolving tank; the pipeline from the primary price adjustment tank to the secondary price adjustment tank mainly plays the role of electrolyte valence supplement; the additives are supplemented to ensure the high stability of the finished electrolyte; the electrolyte after the secondary price adjustment is the finished electrolyte, which can enter the filling process for finished product filling; the slag in the primary price adjustment tank and the liquid outlet tank enters the sludge dewatering machine, the filtrate 2 after dehydration enters the filtrate tank, and the residue 2 enters the residue dissolving tank; S8: The filter residue 1 produced by the filter and the filter residue 2 produced by the sludge dewatering machine are reduced and dissolved in the filter residue dissolution tank through the trivalent vanadium electrolyte refluxed from the liquid outlet tank. The secondary dissolved liquid after dissolution enters the dissolution reaction tank, forming a closed cycle with full utilization of solid and liquid.

[0025] Among them, high-purity vanadium and sulfuric acid in S1 are respectively transported into the activation reaction tank through a powder conveyor and an acid-resistant pump. The purity of high-purity vanadium is ≥99.5%, and the sulfuric acid is 98% industrial-grade acid. The molar ratio of high-purity vanadium to sulfuric acid is between 1:1 and 1:5. The heat source includes one of steam heating, thermal oil heating, and heat pump heating. The heating activation temperature ranges from 40 to 180°C, and the time is 1 to 4 hours. Stirring is provided in the activation reaction tank, and the stirring speed is 60 to 180rpm. The co-solvent is a sulfur-containing compound.

[0026] Among them, the jacketed cooling tank in S2 contains the liquid to be cooled, the jacket contains the refrigerant, including one of cooling water, liquid nitrogen, and liquid ammonia, the cooling temperature is 25-30°C, and the cooling tank is equipped with stirring, and the stirring speed is 45-135rpm.

[0027] Among them, the water quality requirements of desalted water in S3 are conductivity ≤ 0.2us / cm, SiO2 ≤ 20ug / L, the volume ratio of desalted water and the mixed liquid entering the dissolution reaction tank is 2.5:1~5:1, the dissolution reaction tank is equipped with stirring, the stirring speed is 120~240rpm, and the reaction time of the dissolution reaction tank is 30~60min. Among them, the filter is a centrifugal dehydrator, a plate and frame dehydrator, or a spiral dehydrator; when a centrifugal dehydrator is used, the centrifugal speed is 800-2000rpm; when a plate and frame dehydrator is used, the filtration pressure is 0.6-4.5MPa; when a spiral dehydrator is used, the frequency of the driving device for controlling the screw shaft is 25-50Hz; the moisture content of the filtered residue is 30-70%, and it is sent to the residue dissolution tank through a shaftless screw conveyor or a belt conveyor. Among them, the filtrate 1 is mainly composed of tetravalent vanadium, that is, V 4+ ; The filtrate 2 is mainly composed of 3.5-valent and 3-valent, that is, V 3+ and V 3.5+ ; Supplement sulfuric acid to ensure that the sulfate ion concentration in the effluent of the filtrate tank is 4-6M; the filtrate tank is equipped with a stirrer with a stirring speed of 60-180rpm and a residence time of 1-2h; the reflux ratio of the trivalent electrolyte is about 30-60%, the primary price adjustment tank is equipped with a stirrer with a stirring speed of 60-180rpm and a residence time of about 1-2h; the bottom of the primary price adjustment tank is cone-shaped, and a slag discharge device is provided at the bottom of the cone. The slag discharge to the sludge dewatering machine is controlled by a pneumatic or electric regulating valve. The single slag discharge time is 5-15min, and the slag is discharged every 2-4h.

[0028] Among them, the cathode and anode electrode combinations in S6 include one of Pt / Pb, Ti mesh / Pb, RuIrTi mesh / RuIrTi mesh, Ti mesh / RuIrTi mesh and graphite carbon / RuIrTi mesh; the current density range of a single group is 50-200 mA / cm2, the cell voltage range is 3-10 V, the sulfuric acid concentration range on the anode side is 2-6 M, and the electrolysis time is 3-8 h; stirring is provided on the cathode side, and the stirring speed range is 100-600 rpm.

[0029] Among them, the liquid outlet tank in S7 is not equipped with stirring, the tank bottom is in the shape of a cone bucket, and a slag discharge device is provided at the bottom of the cone bucket. The slag discharge to the sludge dewatering machine is controlled by a pneumatic or electric regulating valve. The single slag discharge time is 5 to 15 minutes, and the slag is discharged once every 8 to 12 hours; the reflux ratio of the reflux liquid to the primary price adjustment tank is about 30 to 60%, and the reflux ratio of the electrolyte refluxed to the filter residue dissolution tank is about 20 to 30%, and the remaining part enters the secondary price adjustment tank; the ingredients of the additive include one or more of phosphoric acid, citric acid, acetic acid, ethylenediaminetetraacetic acid, dodecylbenzenesulfonic acid, and lauric acid prepared in different proportions.

[0030] Among them, the sludge dewatering machine in S7 is a centrifugal dewatering machine, a plate-frame dewatering machine or a screw stack dewatering machine. When a centrifugal dewatering machine is used, its centrifugal speed is 800-2000rpm; when a plate-frame dewatering machine is used, its filtration pressure is 0.6-4.5MPa; when a screw stack dewatering machine is used, the frequency of the driving device controlling the screw shaft is 25-50Hz; Among them, the filter residue dissolution tank in S8 is equipped with stirring, the stirring speed is 60-180 rpm, the filter residue dissolution time is 1-4 hours, and after dissolution, it is transported to the dissolution reaction tank through an acid-resistant and wear-resistant pump.

[0031] The process of the present invention can effectively realize the full utilization of vanadium by refluxing low-valent electrolyte to dissolve the filter residue at room temperature and pressure. In addition, this process does not require the use of other reducing agents, no harmful gases are generated, and no subsequent impurity removal is required, thereby ensuring the high purity of the vanadium electrolyte. In addition, the equipment of the electrolysis part of this process is simple and easy to operate, and can achieve continuous electrolysis without stopping to take liquid. The electrolysis part of this process only needs to complete the reduction from 4 valence to 3 valence / 3.5 valence, and does not need to be reduced from 5 valence to 3 valence or 3.5 valence, which reduces the energy consumption of electrolysis; the additive part in the electrolyte is completely independent, can be autonomously regulated, and can be flexibly prepared, and there is no need to modify the production line at a later stage.

[0032] Embodiment 1: S1: Weigh 45.5 g of analytically pure vanadium pentoxide and mix with 53.25 mL of 98% concentrated sulfuric acid and a co-solvent, activate at 170°C for 3 h after ultrasonic dissolution, and obtain a mixed slurry after cooling; S2: A certain amount of desalted water is mixed with the mixed solution in S1, stirred for 1h to fully dissolve the vanadium sulfate salt, filtered to obtain a filtrate with a pentavalent vanadium concentration of 1.16mol / L, and the filter residues are sent to the filter residue dissolution tank one by one with a wet weight of 61.5g. The activated vanadium sulfate salt cannot be completely dissolved, and there is a large amount of residue; S3: The filter residue 1 in the filter residue dissolution tank is dissolved in a certain amount of vanadium electrolyte mainly composed of trivalent vanadium and with a total vanadium concentration of 1.77 mol / L, and stirred at room temperature for 1 hour. There is slight heat release during the reduction process. The wet weight of the filtered filter residue 1 is 10.69 g. The total vanadium concentration of the obtained secondary dissolution liquid is 2.83 mol / L and is transferred to the filter residue dissolution tank. The filter residue 1 remaining in the filtrate S2 is fully utilized, and the utilization rate is 82.6%; S4: The concentration of 4-valent vanadium ions obtained by mixing the reflux filtrate of S3 in the primary price adjustment tank with the pentavalent vanadium electrolyte in S2 is 1.41 mol / L, the concentration of pentavalent vanadium ions is 0.55 mol / L, and the concentration of sulfate is 4.4 mol / L. The high concentration of 4-valent vanadium is diluted to control the total vanadium concentration at 1.96 mol / L. S5: Take 200 mL of vanadium electrolyte in S4 and add it to the cathode side of the electrolytic cell. Add an equal volume of 3.3 mol / L sulfuric acid solution to the anode side. The cathode is a titanium mesh electrode and the anode is a ruthenium-iridium-titanium mesh electrode. Perform electrolytic reduction under constant current conditions with a current density of 60 mA / cm 2 , voltage range 2~3V, electrolysis time is 420min; S6: After the electrolysis is completed, the concentration of trivalent vanadium ions is measured to be 0.97 mol / L, the concentration of tetravalent vanadium ions is 0.88 mol / L, and the concentration of sulfate is 4.4 mol / L, and the electrolyte is transferred to a liquid outlet tank; S7: Additives are added in an amount of 1 wt% potassium phosphate, 4 wt% urea, and 5 vol% glycerol, respectively, into a secondary price adjustment tank to obtain a finished electrolyte.

[0033] The present invention aims at the high energy consumption and harsh reaction conditions of the filter residue produced in the process of producing electrolyte using vanadium pentoxide as raw material, and accelerates the dissolution rate of vanadium-containing filter residue at room temperature by refluxing low-valent vanadium electrolyte, thereby solving the high energy consumption problem and achieving the goal of fully utilizing the raw materials and vanadium slag of high-purity vanadium, and effectively reducing the cost of activation, dissolution and full utilization of vanadium electrolyte for high-purity vanadium production. The present invention aims at the situation that when pentavalent vanadium is reduced to tetravalent vanadium under the condition of reducing agent, the subsequent electrolyte performance is affected by the introduction of reducing agent, and the pentavalent vanadium is reduced by using low-valent vanadium electrolyte as reducing agent, which improves the solubility and avoids the introduction of new substances. The present invention is different from the traditional "two-stage electrolysis + price adjustment", that is, the first-stage electrolysis electrolyzes the valence state of vanadium from 5 to 4, and the second-stage electrolysis reduces the 4-valent electrolyte to 3 / 3.5. The present invention only electrolyzes the 4-valent electrolyte to reduce the valence to 3 / 3.5. Because the theoretical electron transfer number is less than or equal to 1, the energy consumption required for electrolysis and the investment cost of the electrolysis device are reduced compared with the prior art.

[0034] The above description shows and describes the preferred embodiments of the present invention. As mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A short-process vanadium battery electrolyte production process with full solid-liquid utilization, characterized by: The production process comprises the following steps: S1: Mix high-purity vanadium, sulfuric acid and co-solvent in an activation reaction tank, activate at high temperature and then cool; S2: The mixed liquid after high temperature activation enters the jacketed cooling tank, and after cooling, enters the dissolution reaction tank. At this time, the valence state of vanadium is mainly pentavalent, that is, V 5+ sulfuric acid mixture; S3: Inject desalted water into the dissolution reaction tank and mix with V 5+ The mixed liquid and the secondary dissolving liquid from the filter residue dissolving tank are dissolved, and the electrolyte mainly composed of trivalent electrolyte in the liquid outlet tank flows back to the filter residue dissolving tank for mixing; a mixed liquid mainly composed of tetravalent electrolyte is formed, i.e., the secondary dissolving liquid; the dissolved tetravalent crude dissolving liquid enters the filter; S4: The crude solution in S3 is separated into residue and water in a filter to obtain filtrate 1 and filter residue 1. The filtrate 1 enters a filtrate tank, and the filter residue 1 enters a filter residue dissolution tank; S5: The filtrate tank includes filtrate 1, filtrate 2 from the sludge dewatering machine, and supplemented concentrated sulfuric acid, which are mixed evenly and then enter the primary price adjustment tank; the effluent from the filtrate tank flows into the primary price adjustment tank, and the trivalent electrolyte after electrolytic reduction partially flows back from the effluent tank to the primary price adjustment tank; S6: After the first price adjustment is completed, the part of the electrolyte with a valence of 4 as the main electrolyte in the price adjustment tank system enters the cathode chamber and is supplemented with inert gas to be electrolytically reduced to a valence of 3 as the main electrolyte, i.e., V3+; the other part is electrolytically reduced to an average valence state of vanadium of V3.5+ and then directly enters the secondary price adjustment tank; S7: The trivalent electrolyte in the liquid outlet tank is partially refluxed to the primary price adjustment tank through the pump, and partially refluxed to the residue dissolving tank; the pipeline from the primary price adjustment tank to the secondary price adjustment tank mainly plays the role of electrolyte valence supplement; the additives are supplemented to ensure the high stability of the finished electrolyte; the electrolyte after the secondary price adjustment is the finished electrolyte, which can enter the filling process for finished product filling; the slag in the primary price adjustment tank and the liquid outlet tank enters the sludge dewatering machine, the filtrate 2 after dehydration enters the filtrate tank, and the residue 2 enters the residue dissolving tank; S8: The filter residue 1 produced by the filter and the filter residue 2 produced by the sludge dewatering machine are reduced and dissolved in the filter residue dissolution tank through the trivalent vanadium electrolyte refluxed from the liquid outlet tank. The secondary dissolved liquid after dissolution enters the dissolution reaction tank, forming a closed cycle with full utilization of solid and liquid.

2. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 1 is characterized in that: The high-purity vanadium and sulfuric acid in S1 are respectively conveyed into the activation reaction tank by a powder conveyor and an acid-resistant pump. The purity of the high-purity vanadium is ≥99.5%, the sulfuric acid is 98% industrial-grade acid, the molar ratio of high-purity vanadium to sulfuric acid is between 1:1 and 1:5, the heat source comprises one of steam heating, thermal oil heating, and heat pump heating, the heating activation temperature range is 40 to 180°C, the time is 1 to 4 h, the activation reaction tank is provided with stirring, the stirring speed is 60 to 180 rpm, and the co-solvent is a sulfur-containing compound.

3. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 1 is characterized in that: The jacketed cooling tank in S2 contains liquid to be cooled, and the jacket contains refrigerant, including one of cooling water, liquid nitrogen, and liquid ammonia. The cooling temperature is 25-30°C, and stirring is provided in the cooling tank, and the stirring speed is 45-135 rpm.

4. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 3 is characterized in that: The desalted water quality in the S3 requires conductivity ≤ 0.2us / cm, SiO2 ≤ 20ug / L, the volume ratio of the desalted water and the mixed liquid entering the dissolution reaction tank is 2.5:1-5:1, the dissolution reaction tank is provided with stirring, the stirring speed is 120-240rpm, and the reaction time of the dissolution reaction tank is 30-60min.

5. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 4 is characterized in that: The filter is a centrifugal dehydrator, a plate and frame dehydrator or a screw stack dehydrator; when a centrifugal dehydrator is used, the centrifugal speed is 800-2000rpm; when a plate and frame dehydrator is used, the filtration pressure is 0.6-4.5MPa; when a screw stack dehydrator is used, the frequency of the driving device for controlling the screw shaft is 25-50Hz; the moisture content of the filtered residue is 30-70%, and it is sent to the residue dissolution tank through a shaftless screw conveyor or a belt conveyor.

6. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 5 is characterized in that: The filtrate 1 is mainly composed of tetravalent vanadium, i.e., V 4+ ; The filtrate 2 is mainly composed of 3.5-valent and 3-valent, that is, V 3+ and V 3.5+ ; Supplement sulfuric acid to ensure that the sulfate ion concentration in the effluent of the filtrate tank is 4-6M; the filtrate tank is equipped with a stirrer with a stirring speed of 60-180rpm and a residence time of 1-2 h; the reflux ratio of the trivalent electrolyte is about 30-60%, the primary price adjustment tank is equipped with a stirrer with a stirring speed of 60-180rpm and a residence time of about 1-2 h; the bottom of the primary price adjustment tank is cone-shaped, and a slag discharge device is provided at the bottom of the cone, which is controlled by a pneumatic or electric regulating valve to discharge the sludge to the sludge dewatering machine. The single slag discharge time is 5-15min, and the slag is discharged every 2-4 hours.

7. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 6 is characterized in that: The cathode and anode electrode combination in S6 comprises one of Pt / Pb, Ti mesh / Pb, RuIrTi mesh / RuIrTi mesh, Ti mesh / RuIrTi mesh or graphite carbon / RuIrTi mesh; the current density range of a single group is 50-200 mA / cm 2 The cell voltage range is 3-10V, the sulfuric acid concentration range of the anode plate is 2-6M, and the electrolysis time is 3-8h; the cathode chamber is equipped with stirring, and the stirring speed range is 100-600rpm.

8. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 7 is characterized in that: The liquid outlet tank in the S7 is not equipped with stirring, and the bottom of the tank is in the shape of a cone bucket. A slag discharge device is provided at the bottom of the cone bucket. The slag discharge to the sludge dewatering machine is controlled by a pneumatic or electric regulating valve. The single slag discharge time is 5 to 15 minutes, and the slag is discharged once every 8 to 12 hours; the reflux ratio of the reflux liquid to the primary price adjustment tank is about 30 to 60%, and the reflux ratio of the electrolyte refluxed to the filter residue dissolution tank is about 20 to 30%, and the remaining part enters the secondary price adjustment tank; the ingredients of the additive include one or more of phosphoric acid, citric acid, acetic acid, ethylenediaminetetraacetic acid, dodecylbenzenesulfonic acid, and lauric acid prepared in different proportions.

9. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 8 is characterized in that: The sludge dewatering machine in S7 is a centrifugal dewatering machine, a plate and frame dewatering machine, or a screw dewatering machine.

10. The short-process vanadium battery electrolyte production process with full solid-liquid utilization according to claim 8 is characterized in that: The filter residue dissolving tank in S8 is provided with a stirring device, the stirring speed is 60-180 rpm, the filter residue dissolving time is 1-4 hours, and after dissolution, it is transported to the dissolution reaction tank through an acid-resistant and wear-resistant pump.

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