Treatment method of vanadium electrolyte production wastewater

Abstract

The invention relates to the technical field of environmental protection, in particular to a treatment method of vanadium electrolyte production wastewater. The method comprises the following steps: inputting wastewater generated in a vanadium electrolyte production process into a micro-bubble reactor, then carrying out micro-reduction and neutralization precipitation treatment, after the reaction treatment is completed, enabling upper-layer clear liquid containing organic matters in the micro-bubble reactor to flow into a high-potential catalytic oxidation reaction tank, and discharging lower-layer slurry into a membrane concentration tank; carrying out catalytic oxidation treatment on the clear liquid containing the organic matters in a high-potential catalytic oxidation reaction tank to obtain a purified solution; carrying out concentration and filtration treatment on the slurry-containing wastewater through a membrane concentration tank to obtain filtrate and concentrated slurry, and carrying out filter pressing and washing on the concentrated slurry to obtain vanadium-chromium sludge; inputting and mixing the purified solution and the filtrate, and sending the mixture to an evaporation and concentration device for treatment to obtain anhydrous sodium sulfate. The method solves the problem that the vanadium electrolyte production wastewater is difficult to treat or utilize resources, so that zero discharge of the wastewater is realized.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a method for treating wastewater produced by vanadium electrolyte production. Background Art

[0002] The low-cost production of vanadium electrolyte adopts the direct extraction process of vanadium precipitation solution. The solution after vanadium extraction contains about 0.5g / L vanadium, about 2.0g / L chromium, 10-15mg / L oil, 100-200mg / L organic matter and about 18% salt. It becomes wastewater and needs to be discharged for treatment. However, it is difficult to meet the treatment standards, the process occupies a large area and the process is long.

[0003] At present, this type of wastewater is transported by tank trucks to the vanadium precipitation wastewater treatment system for mixed treatment. However, since the wastewater treatment system does not have the function of removing oil and organic matter, it leads to blockage of the wastewater system, low product purity, poor appearance, and difficulty in using sludge. In addition, the wastewater is in the industrial park. With the increasingly stringent national requirements for ecological and environmental protection, as well as the ecological protection of the Yangtze River Basin, local standards are limited to the access conditions of industrial park wastewater. This wastewater must be treated harmlessly and resourcefully. To this end, a method for treating vanadium electrolyte production wastewater is proposed to solve the above problems. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a method for treating vanadium electrolyte production wastewater.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: In a first aspect, in one embodiment provided by the present invention, a method for treating vanadium electrolyte production wastewater is provided, the method comprising the following steps: The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged to the membrane concentration tank; The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high-potential catalytic oxidation reaction tank to obtain a purified solution; The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge; The purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0006] As a further embodiment of the present invention, the micro-reduction and neutralization precipitation treatment comprises: Under aeration, add reducing agent at 0.5% to 1.0% of the total mass of vanadium and chromium, react for 5 to 10 minutes, add alkaline solution to adjust the pH to 7.2 to 7.5, adjust the aeration volume and continue to react for 30 to 45 minutes to make the concentration of vanadium and chromium less than 0.5 mg / L. At the same time, make the organic matter containing extractant and oil suspended in the wastewater float to the surface and let it stand for 1 to 1.5 hours.

[0007] As a further solution of the present invention, the microbubble reactor is a TV-type high-efficiency dissolved gas system.

[0008] As a further embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0009] As a further embodiment of the present invention, a clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprising: The stirring speed of the high-potential catalytic oxidation reaction tank is 300-360 rpm, and the degradation time is 30-45 min.

[0010] As a further solution of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.3-0.5cm, an operating voltage of 2-4V controlled by a voltage-stabilized power supply, and a current density of 5-10mA / cm 2 .

[0011] As a further embodiment of the present invention, the membrane concentration tank comprises a flat membrane filtration concentration tank.

[0012] As a further solution of the present invention, the flat membrane filtration and concentration tank is compressed by a silicon carbide ceramic membrane, with a filtration pore size of 0.5 to 1 um and a filtration pressure of 0.05 to 0.1 MPa.

[0013] As a further solution of the present invention, the plate and frame filter is a fully automatic filter washing machine with a filtration accuracy of 5 to 8 um.

[0014] As a further embodiment of the present invention, the purified solution and the filtrate are input into a mixed evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprising: During the treatment process, the stirring speed is 160-200 rpm and the evaporation temperature is 95-105°C.

[0015] The technical solution provided by the present invention has the following beneficial effects: The method for treating vanadium electrolyte production wastewater provided by the present invention comprises the following steps: micro-reduction of vanadium electrolyte production wastewater, neutralization precipitation, micro-bubble separation of suspended organic matter, catalytic oxidation treatment of organic-containing brine, membrane concentration filtration of muddy wastewater, and evaporation and crystallization of purified wastewater. After the above steps, vanadium and chromium resources are recovered to obtain a high-purity anhydrous sodium sulfate product, thereby solving the problem of difficult treatment or resource utilization of vanadium electrolyte production wastewater and achieving zero discharge of wastewater.

[0016] These and other aspects of the present invention will be more clearly understood in the following description of the embodiments. It should be understood that the above general description and the following detailed description are only exemplary and explanatory and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a specific flow chart of a method for treating vanadium electrolyte production wastewater according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0021] like Figure 1 As shown, the present invention provides a method for treating wastewater produced by vanadium electrolyte, and the method for treating wastewater produced by vanadium electrolyte comprises the following steps: S1. The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged into the membrane concentration tank.

[0022] In the embodiment of the present invention, the micro-reduction and neutralization precipitation treatment includes: Under aeration, add reducing agent at 0.5% to 1.0% of the total mass of vanadium and chromium, react for 5 to 10 minutes, add alkaline solution to adjust the pH to 7.2 to 7.5, adjust the aeration volume and continue to react for 30 to 45 minutes to make the concentration of vanadium and chromium less than 0.5 mg / L. At the same time, make the organic matter containing extractant and oil suspended in the wastewater float to the surface and let it stand for 1 to 1.5 hours.

[0023] In the embodiment of the present invention, the microbubble reactor is a TV type high-efficiency dissolved gas system with a working pressure of 0.15-0.2Mpa and a bubble size of 10-30um. The gas source used in this process is N2 to ensure that the reaction process is reducing to fully remove vanadium and chromium.

[0024] The bubbles generated by the microbubble reactor will bring out the emulsified oil organic matter suspended in the wastewater and entrained in the sediment and float it on the surface of the wastewater, fully separating the organic matter and reducing its impact on subsequent treatment processes and the appearance of the product.

[0025] In the embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0026] In the embodiment of the present invention, the alkaline solution is 40-42% liquid caustic soda, which is produced by chlor-alkali ion membrane electrolysis and has low cost. This concentration reduces the amount of water brought in and ensures the water balance of the system.

[0027] S2. The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution.

[0028] In the embodiment of the present invention, the step S2, catalytically oxidizing the clear liquid containing organic matter in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprises: The stirring speed of the high-potential catalytic oxidation reaction tank is 300-360rpm, and the degradation time is 30-45min. After degradation, the organic matter is completely decomposed, the oil content is less than 0.5mg / L, and the COD is less than 15mg / L. The purified solution is mixed with membrane concentrated brine after precision filtration.

[0029] In the embodiment of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.3-0.5cm, an operating voltage of 2-4V controlled by a voltage-stabilized power supply, and a current density of 5-10mA / cm 2 At the same time, a gas extraction system is provided on the upper part of the high potential catalytic oxidation reaction tank, and the collected gas can be sent to the microbubble reactor as supplementary gas.

[0030] S3. The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge.

[0031] In the embodiment of the present invention, the S3, the muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge, including: The membrane concentration tank comprises a flat membrane filtration concentration tank.

[0032] In the embodiment of the present invention, the flat membrane filtration concentration tank is compressed by a silicon carbide ceramic membrane, the filtration pore size is 0.5-1um, and the filtration pressure is 0.05-0.1Mpa. The flat membrane filtration concentration tank has the advantages of small footprint and high filtration accuracy.

[0033] In the embodiment of the present invention, the concentrated slurry is filtered through a plate and frame filter.

[0034] In the embodiment of the present invention, the plate and frame filter is a fully automatic filter washing machine of Chengdu Changjie Technology Co., Ltd., with a filtration accuracy of 5 to 8 um, made of high-pressure resistant polyvinyl chloride, and the washing is a countercurrent three-stage washing.

[0035] It should be noted that the components of the filtrate are Na + :50~55g / L、SO4 2- :145~150g / L、Cl - <0.5g / L, V≤0.2mg / L, Cr≤0.1mg / L, Ca<0.01g / L, pH6.5~7.0.

[0036] S4, the purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0037] The step S4, inputting the purified solution and the filtrate into a mixed solution and sending them to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprises: During the treatment process, the stirring speed is 160-200 rpm, the evaporation temperature is 95-105° C., the mixture is concentrated to saturation with sodium sulfate, and the temperature is lowered to 85° C. to crystallize out anhydrous sodium sulfate.

[0038] It should be noted that the solid-liquid separation in step S4 obtains anhydrous sodium sulfate with a purity greater than 98.5%, and the condensed water is used as water for washing the vanadium-chromium sludge.

[0039] The present invention performs micro-reduction, neutralization precipitation, micro-bubble separation of suspended organic matter, catalytic oxidation treatment of organic-containing brine, membrane concentration filtration of muddy wastewater, and evaporation and crystallization of purified wastewater. After the above steps, vanadium and chromium resources are recovered to obtain a high-purity anhydrous sodium sulfate product, thereby solving the problem of difficult treatment or resource utilization of vanadium electrolyte production wastewater and achieving zero discharge of wastewater.

[0040] Example 1 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged into the membrane concentration tank.

[0041] In the embodiment of the present invention, the micro-reduction and neutralization precipitation treatment includes: Under aeration, add reducing agent at 0.5% of the total mass of vanadium and chromium, react for 5 minutes, add alkaline solution to adjust the pH to 7.2, adjust the aeration volume and continue to react for 30 minutes to make the vanadium and chromium concentrations less than 0.5 mg / L. At the same time, make the organic matter containing extractant and oil suspended in the wastewater float to the surface and let it stand for 1 hour.

[0042] In the embodiment of the present invention, the microbubble reactor is a TV type high-efficiency dissolved gas system with a working pressure of 0.15 MPa and a bubble size of 10 to 30 um. The gas source used in this process is N2 to ensure that the reaction process is reductive so as to fully remove vanadium and chromium.

[0043] The bubbles generated by the microbubble reactor will bring out the emulsified oil organic matter suspended in the wastewater and entrained in the sediment and float it on the surface of the wastewater, fully separating the organic matter and reducing its impact on subsequent treatment processes and the appearance of the product.

[0044] In the embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0045] In the embodiment of the present invention, the alkaline solution is 40-42% liquid caustic soda, which is produced by chlor-alkali ion membrane electrolysis and has low cost. This concentration reduces the amount of water brought in and ensures the water balance of the system.

[0046] S2. The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution.

[0047] In the embodiment of the present invention, the step S2, catalytically oxidizing the clear liquid containing organic matter in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprises: The stirring speed of the high-potential catalytic oxidation reaction tank is 300 rpm, and the degradation time is 30 minutes. After degradation, the organic matter is completely decomposed, the oil content is less than 0.5 mg / L, and the COD is less than 15 mg / L. The purified solution is finely filtered and then mixed with membrane concentrated brine.

[0048] In the embodiment of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.3cm, an operating voltage of 2-4V controlled by a voltage regulator, and a current density of 5mA / cm 2 At the same time, a gas extraction system is provided on the upper part of the high potential catalytic oxidation reaction tank, and the collected gas can be sent to the microbubble reactor as supplementary gas.

[0049] S3. The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge.

[0050] In the embodiment of the present invention, the S3, the muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge, including: In an embodiment of the present invention, the membrane concentration tank comprises a flat membrane filtration concentration tank.

[0051] In the embodiment of the present invention, the flat membrane filtration concentration tank is pressed by a silicon carbide ceramic membrane, the filtration pore size is 0.5um, and the filtration pressure is 0.05Mpa. The flat membrane filtration concentration tank has the advantages of small footprint and high filtration accuracy.

[0052] In the embodiment of the present invention, the concentrated slurry is filtered through a plate and frame filter.

[0053] In the embodiment of the present invention, the plate and frame filter is a fully automatic filter washing machine of Chengdu Changjie Technology Co., Ltd., with a filtration accuracy of 5 to 8 um, made of high-pressure resistant polyvinyl chloride, and the washing is a countercurrent three-stage washing.

[0054] It should be noted that the components of the filtrate are Na + :50~55g / L、SO4 2- :145~150g / L、Cl - <0.5g / L, V≤0.2mg / L, Cr≤0.1mg / L, Ca<0.01g / L, pH6.5~7.0.

[0055] S4, the purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0056] The step S4, inputting the purified solution and the filtrate into a mixed solution and sending them to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprises: During the treatment, the stirring speed is 160 rpm and the evaporation temperature is 95°C. The solution is concentrated to saturation with sodium sulfate and then cooled to 85°C to crystallize anhydrous sodium sulfate.

[0057] Example 2 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged into the membrane concentration tank.

[0058] In the embodiment of the present invention, the micro-reduction and neutralization precipitation treatment includes: Under aeration, add reducing agent at 1.0% of the total mass of vanadium and chromium, react for 10 minutes, add alkaline solution to adjust the pH to 7.5, adjust the aeration volume and continue to react for 45 minutes to make the concentration of vanadium and chromium less than 0.5 mg / L. At the same time, make the organic matter containing extractant and oil suspended in the wastewater float to the surface and let it stand for 1.5 hours.

[0059] In the embodiment of the present invention, the microbubble reactor is a TV type high-efficiency dissolved gas system with a working pressure of 0.2 MPa and a bubble size of 30 um. The gas source used in this process is N2 to ensure that the reaction process is reductive so as to fully remove vanadium and chromium.

[0060] The bubbles generated by the microbubble reactor will bring out the emulsified oil organic matter suspended in the wastewater and entrained in the sediment and float it on the surface of the wastewater, fully separating the organic matter and reducing its impact on subsequent treatment processes and the appearance of the product.

[0061] In the embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0062] In the embodiment of the present invention, the alkaline solution is 42% liquid caustic soda, which is produced by chlor-alkali ion membrane electrolysis and has low cost. This concentration reduces the amount of water brought in and ensures the water balance of the system.

[0063] S2. The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution.

[0064] In the embodiment of the present invention, the step S2, catalytically oxidizing the clear liquid containing organic matter in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprises: The stirring speed of the high-potential catalytic oxidation reaction tank is 360rpm, and the degradation time is 45min. After degradation, the organic matter is completely decomposed, the oil content is less than 0.5mg / L, and the COD is less than 15mg / L. The purified solution is finely filtered and mixed with membrane concentrated brine.

[0065] In the embodiment of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.5cm, an operating voltage of 4V controlled by a voltage regulator, and a current density of 10mA / cm 2 At the same time, a gas extraction system is provided on the upper part of the high potential catalytic oxidation reaction tank, and the collected gas can be sent to the microbubble reactor as supplementary gas.

[0066] S3. The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge.

[0067] In the embodiment of the present invention, the S3, the muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge, including: In an embodiment of the present invention, the membrane concentration tank comprises a flat membrane filtration concentration tank.

[0068] In the embodiment of the present invention, the flat membrane filtration concentration tank is pressed by a silicon carbide ceramic membrane, the filtration pore size is 1um, and the filtration pressure is 0.1Mpa. The flat membrane filtration concentration tank has the advantages of small footprint and high filtration accuracy.

[0069] In the embodiment of the present invention, the concentrated slurry is filtered through a plate and frame filter.

[0070] In the embodiment of the present invention, the plate and frame filter is a fully automatic filter washing machine of Chengdu Changjie Technology Co., Ltd., with a filtration accuracy of 5 to 8 um, made of high-pressure resistant polyvinyl chloride, and the washing is a countercurrent three-stage washing.

[0071] It should be noted that the components of the filtrate are Na + :50~55g / L、SO4 2- :145~150g / L、Cl - <0.5g / L, V≤0.2mg / L, Cr≤0.1mg / L, Ca<0.01g / L, pH6.5~7.0.

[0072] S4, the purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0073] The step S4, inputting the purified solution and the filtrate into a mixed solution and sending them to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprises: During the treatment, the stirring speed was 200 rpm and the evaporation temperature was 105° C. The mixture was concentrated to saturation with sodium sulfate and then cooled to 85° C. to crystallize anhydrous sodium sulfate.

[0074] Example 3 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged into the membrane concentration tank.

[0075] In the embodiment of the present invention, the micro-reduction and neutralization precipitation treatment includes: Under aeration, a reducing agent was added at 0.6% of the total mass of vanadium and chromium, and the reaction was continued for 6 minutes. An alkaline solution was added to adjust the pH to 7.25, and the aeration volume was adjusted to continue the reaction for 33 minutes to make the concentration of vanadium and chromium less than 0.5 mg / L. At the same time, the organic matter containing the extractant and oil suspended in the wastewater floated to the surface and was allowed to stand for 1.1 hours.

[0076] In the embodiment of the present invention, the microbubble reactor is a TV type high-efficiency dissolved gas system with a working pressure of 0.16Mpa and a bubble size of 15um. The gas source used in this process is N2 to ensure that the reaction process is reductive so as to fully remove vanadium and chromium.

[0077] The bubbles generated by the microbubble reactor will bring out the emulsified oil organic matter suspended in the wastewater and entrained in the sediment and float it on the surface of the wastewater, fully separating the organic matter and reducing its impact on subsequent treatment processes and the appearance of the product.

[0078] In the embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0079] In the embodiment of the present invention, the alkaline solution is 40.5% liquid caustic soda, which is produced by chlor-alkali ion membrane electrolysis and has low cost. This concentration reduces the amount of water brought in and ensures the water balance of the system.

[0080] S2. The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution.

[0081] In the embodiment of the present invention, the step S2, catalytically oxidizing the clear liquid containing organic matter in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprises: The stirring speed of the high-potential catalytic oxidation reaction tank is 310 rpm, and the degradation time is 33 minutes. After degradation, the organic matter is completely decomposed, the oil content is less than 0.5 mg / L, and the COD is less than 15 mg / L. The purified solution is finely filtered and then mixed with membrane concentrated brine.

[0082] In the embodiment of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.35cm, an operating voltage of 2.5V and a current density of 6mA / cm2 controlled by a voltage regulator. 2 At the same time, a gas extraction system is provided on the upper part of the high potential catalytic oxidation reaction tank, and the collected gas can be sent to the microbubble reactor as supplementary gas.

[0083] S3. The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge.

[0084] In the embodiment of the present invention, the S3, the muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge, including: In an embodiment of the present invention, the membrane concentration tank comprises a flat membrane filtration concentration tank.

[0085] In the embodiment of the present invention, the flat membrane filtration concentration tank is pressed by a silicon carbide ceramic membrane, the filtration pore size is 0.6um, and the filtration pressure is 0.06Mpa. The flat membrane filtration concentration tank has the advantages of small footprint and high filtration accuracy.

[0086] In the embodiment of the present invention, the concentrated slurry is filtered through a plate and frame filter.

[0087] In the embodiment of the present invention, the plate and frame filter is a fully automatic filter washing machine of Chengdu Changjie Technology Co., Ltd., with a filtration accuracy of 5 to 8 um, made of high-pressure resistant polyvinyl chloride, and the washing is a countercurrent three-stage washing.

[0088] It should be noted that the components of the filtrate are Na + :50~55g / L、SO4 2- :145~150g / L、Cl - <0.5g / L, V≤0.2mg / L, Cr≤0.1mg / L, Ca<0.01g / L, pH6.5~7.0.

[0089] S4, the purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0090] The step S4, inputting the purified solution and the filtrate into a mixed solution and sending them to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprises: During the treatment, the stirring speed is 170 rpm and the evaporation temperature is 98° C. The solution is concentrated to saturation with sodium sulfate and then cooled to 85° C. to crystallize anhydrous sodium sulfate.

[0091] Example 4 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged into the membrane concentration tank.

[0092] In the embodiment of the present invention, the micro-reduction and neutralization precipitation treatment includes: Under aeration, a reducing agent was added at 0.9% of the total mass of vanadium and chromium, and the reaction was carried out for 9 minutes. An alkaline solution was added to adjust the pH to 7.45, and the aeration volume was adjusted to continue the reaction for 42 minutes to make the vanadium and chromium concentrations less than 0.5 mg / L. At the same time, the organic matter containing the extractant and oil suspended in the wastewater floated to the surface and was allowed to stand for 1.4 hours.

[0093] In the embodiment of the present invention, the microbubble reactor is a TV type high-efficiency dissolved gas system with a working pressure of 0.19 MPa and a bubble size of 25 um. The gas source used in this process is N2 to ensure that the reaction process is reductive so as to fully remove vanadium and chromium.

[0094] The bubbles generated by the microbubble reactor will bring out the emulsified oil organic matter suspended in the wastewater and entrained in the sediment and float it on the surface of the wastewater, fully separating the organic matter and reducing its impact on subsequent treatment processes and the appearance of the product.

[0095] In the embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0096] In the embodiment of the present invention, the alkaline solution is 41.5% liquid caustic soda, which is produced by chlor-alkali ion membrane electrolysis and has low cost. This concentration reduces the amount of water brought in and ensures the water balance of the system.

[0097] S2. The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution.

[0098] In the embodiment of the present invention, the step S2, catalytically oxidizing the clear liquid containing organic matter in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprises: The stirring speed of the high-potential catalytic oxidation reaction tank is 350 rpm, and the degradation time is 42 minutes. After degradation, the organic matter is completely decomposed, the oil content is less than 0.5 mg / L, and the COD is less than 15 mg / L. The purified solution is finely filtered and mixed with membrane concentrated brine.

[0099] In the embodiment of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.45cm, an operating voltage of 3.5V and a current density of 9mA / cm2 controlled by a voltage regulator. 2 At the same time, a gas extraction system is provided on the upper part of the high potential catalytic oxidation reaction tank, and the collected gas can be sent to the microbubble reactor as supplementary gas.

[0100] S3. The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge.

[0101] In the embodiment of the present invention, the S3, the muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge, including: In an embodiment of the present invention, the membrane concentration tank comprises a flat membrane filtration concentration tank.

[0102] In the embodiment of the present invention, the flat membrane filtration concentration tank is pressed by a silicon carbide ceramic membrane, the filtration pore size is 0.9um, and the filtration pressure is 0.09Mpa. The flat membrane filtration concentration tank has the advantages of small footprint and high filtration accuracy.

[0103] In the embodiment of the present invention, the concentrated slurry is filtered through a plate and frame filter.

[0104] In the embodiment of the present invention, the plate and frame filter is a fully automatic filter washing machine of Chengdu Changjie Technology Co., Ltd., with a filtration accuracy of 8um, made of high-pressure resistant polyvinyl chloride, and the washing is a countercurrent three-stage washing.

[0105] It should be noted that the components of the filtrate are Na + :50~55g / L、SO4 2- :145~150g / L、Cl - <0.5g / L, V≤0.2mg / L, Cr≤0.1mg / L, Ca<0.01g / L, pH6.5~7.0.

[0106] S4, the purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0107] The step S4, inputting the purified solution and the filtrate into a mixed solution and sending them to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprises: During the treatment, the stirring speed is 190 rpm and the evaporation temperature is 102°C. The solution is concentrated to saturation with sodium sulfate and then cooled to 85°C to crystallize anhydrous sodium sulfate.

[0108] Example 5 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged into the membrane concentration tank.

[0109] In the embodiment of the present invention, the micro-reduction and neutralization precipitation treatment includes: Under aeration, a reducing agent was added at 0.75% of the total mass of vanadium and chromium, and the reaction was continued for 7 minutes. An alkaline solution was added to adjust the pH to 7.4, and the aeration volume was adjusted to continue the reaction for 28 minutes to make the vanadium and chromium concentrations less than 0.5 mg / L. At the same time, the organic matter containing the extractant and oil suspended in the wastewater floated to the surface and was allowed to stand for 1.2 hours.

[0110] In the embodiment of the present invention, the microbubble reactor is a TV type high-efficiency dissolved gas system with a working pressure of 0.18 MPa and a bubble size of 20 um. The gas source used in this process is N2 to ensure that the reaction process is reductive so as to fully remove vanadium and chromium.

[0111] The bubbles generated by the microbubble reactor will bring out the emulsified oil organic matter suspended in the wastewater and entrained in the sediment and float it on the surface of the wastewater, fully separating the organic matter and reducing its impact on subsequent treatment processes and the appearance of the product.

[0112] In the embodiment of the present invention, the reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

[0113] In the embodiment of the present invention, the alkaline solution is 41% liquid caustic soda, which is produced by chlor-alkali ion membrane electrolysis and has low cost. This concentration reduces the amount of water brought in and ensures the water balance of the system.

[0114] S2. The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution.

[0115] In the embodiment of the present invention, the step S2, catalytically oxidizing the clear liquid containing organic matter in a high potential catalytic oxidation reaction tank to obtain a purified solution, comprises: The stirring speed of the high-potential catalytic oxidation reaction tank is 330 rpm, and the degradation time is 38 minutes. After degradation, the organic matter is completely decomposed, the oil content is less than 0.5 mg / L, and the COD is less than 15 mg / L. The purified solution is finely filtered and then mixed with membrane concentrated brine.

[0116] In the embodiment of the present invention, the high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.4cm, an operating voltage of 3V controlled by a voltage regulator, and a current density of 7mA / cm 2 At the same time, a gas extraction system is provided on the upper part of the high potential catalytic oxidation reaction tank, and the collected gas can be sent to the microbubble reactor as supplementary gas.

[0117] S3. The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge.

[0118] In the embodiment of the present invention, the S3, the muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge, including: In an embodiment of the present invention, the membrane concentration tank comprises a flat membrane filtration concentration tank.

[0119] In the embodiment of the present invention, the flat membrane filtration concentration tank is pressed by a silicon carbide ceramic membrane, the filtration pore size is 0.8um, and the filtration pressure is 0.08Mpa. The flat membrane filtration concentration tank has the advantages of small footprint and high filtration accuracy.

[0120] In the embodiment of the present invention, the concentrated slurry is filtered through a plate and frame filter.

[0121] In the embodiment of the present invention, the plate and frame filter is a fully automatic filter washing machine of Chengdu Changjie Technology Co., Ltd., with a filtration accuracy of 5 to 8 um, made of high-pressure resistant polyvinyl chloride, and the washing is a countercurrent three-stage washing.

[0122] It should be noted that the components of the filtrate are Na + :50~55g / L、SO4 2- :145~150g / L、Cl - <0.5g / L, V≤0.2mg / L, Cr≤0.1mg / L, Ca<0.01g / L, pH6.5~7.0.

[0123] S4, the purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

[0124] The step S4, inputting the purified solution and the filtrate into a mixed solution and sending them to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, comprises: During the treatment, the stirring speed is 180 rpm and the evaporation temperature is 100° C. The mixture is concentrated to saturation with sodium sulfate and then cooled to 85° C. to crystallize out anhydrous sodium sulfate.

[0125] Example 6 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater from vanadium electrolyte production is pumped into a microbubble reactor. Under the action of aeration, sodium metabisulfite reducing agent is added at 1.0% of the total mass of (V+Cr). The reaction is carried out for 10 minutes. 40% liquid caustic soda is added to adjust the pH to 7.3. The aeration is adjusted to microbubbles. After reacting for 45 minutes, aeration is stopped. The solution is allowed to stand for 1.5 hours. The solution is divided into upper, middle and lower layers. The lower part is a concentrated vanadium-chromium slurry, the middle part is a solution for removing organic matter, V and Cr, and the upper part is oily organic wastewater.

[0126] S2, oily organic wastewater was scraped into the high potential catalytic oxidation tank, the power supply was turned on and the voltage was adjusted to a stable 4V, and the degradation was carried out for 45 minutes. The clear liquid was taken to analyze the oil content and COD, and the results showed that the oil content was 0.2mg / L and the COD content was 6mg / L. The degraded brine was then filtered through a 1.0 micron precision filter and sent to the concentrated brine pool.

[0127] S3. Send the remaining wastewater and slurry from the microbubble reactor to the flat membrane filtration concentration tank, start the membrane filtration, and the vanadium-chromium sludge is retained on the membrane surface. The filtrate is sent to the concentrated brine pool through the inner tube. The composition of the obtained filtrate is shown in Table 1. The V content is 0.1 mg / L, Cr<0.1 mg / L, the salt content is concentrated to a certain extent, reaching about 20%, and the pH is weakly acidic, so it can be directly sent to the evaporation concentration device for further concentration.

[0128] Table 1 Brine composition after flat membrane filtration / g / L

[0129] The sludge retained on the membrane surface was filtered through plate and frame, washed, and dried at 105°C. Its composition is shown in Table 2. The Cr content reached about 23%, which can be further purified.

[0130] Table 2 Analysis results of components of vanadium-chromium sludge after drying / %

[0131] S4, pump the brine from the concentration pool into the evaporation concentration device and further concentrate it to saturation at 100℃~105℃ to make Na +The content reaches 120-130 g / L, and is discharged into the DBT crystallizer. 0.2% sodium sulfate seed is added, and the stirring speed is controlled at 180 rpm, gradually reduced to 85 ° C, and kept warm for 2 hours. Finally, high-purity anhydrous sodium sulfate is obtained by centrifugation. After drying, its indicators are shown in Table 3, which meets the anhydrous sodium sulfate product standard Class II superior product.

[0132] Table 3 Index of anhydrous sodium sulfate after drying

[0133] Example 7 A method for treating vanadium electrolyte production wastewater comprises the following steps: S1. The wastewater from vanadium electrolyte production is pumped into a microbubble reactor. Under the action of aeration, sodium metabisulfite reducing agent is added at 0.6% of the total mass of (V+Cr). The reaction is carried out for 10 minutes. 40% liquid caustic soda is added to adjust the pH to 7.5. The aeration is adjusted to microbubbles. After reacting for 30 minutes, aeration is stopped. The solution is allowed to stand for 1.0 hour. The solution is divided into upper, middle and lower layers. The lower part is a concentrated vanadium-chromium slurry, the middle part is a solution for removing organic matter, V and Cr, and the upper part is oily organic wastewater.

[0134] S2, scrape the oily organic wastewater into the high potential catalytic oxidation tank, turn on the power supply and adjust the voltage to a stable 3V, degrade for 45 minutes, The clear liquid was taken to analyze the oil content and COD, and the results showed that the oil content was 0.5 mg / L and the COD content was 12 mg / L. The degraded brine was then filtered through a 1.0 micron precision filter and sent to the concentrated brine pool.

[0135] S3, send the remaining wastewater and slurry of the microbubble reactor to the flat membrane filtration concentration tank, start the membrane filtration, and the vanadium-chromium sludge is The filtrate is retained on the membrane surface and sent to the concentrated brine pool through the inner tube. The composition of the obtained filtrate is shown in Table 4. The V content is 0.6 mg / L, the Cr content is 0.3 mg / L, the salt content is concentrated to a certain extent, reaching about 20%, and the pH is weakly acidic, so it can be directly sent to the evaporation concentration device for further concentration.

[0136] Table 4 Brine composition after flat membrane filtration / g / L

[0137] The sludge retained on the membrane surface was filtered through plate and frame, washed, and dried at 105°C. Its composition is shown in Table 5. The Cr content reached about 23%, which can be further purified.

[0138] Table 5 Analysis results of components of vanadium-chromium sludge after drying / %

[0139] S4, pump the brine from the concentration pool into the evaporation concentration device and further concentrate it to saturation at 100℃~105℃ to make Na + The content reaches 120-130 g / L, and is discharged into the DBT crystallizer. 0.2% sodium sulfate seed is added, and the stirring speed is controlled at 180 rpm, gradually reduced to 85 ° C, and kept warm for 2 hours. Finally, high-purity anhydrous sodium sulfate is obtained by centrifugation. After drying, its indicators are shown in Table 6, which meets the anhydrous sodium sulfate product standard Class II superior product.

[0140] Table 6 Index of anhydrous sodium sulfate after drying

[0141] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for treating vanadium electrolyte production wastewater, characterized in that: The method includes: The wastewater generated in the vanadium electrolyte production process is input into the microbubble reactor, and then subjected to micro-reduction and neutralization precipitation treatment. After the reaction treatment is completed, the upper layer of organic-containing clear liquid in the microbubble reactor flows into the high-potential catalytic oxidation reaction tank, and the lower layer of slurry is discharged to the membrane concentration tank; The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high-potential catalytic oxidation reaction tank to obtain a purified solution; The muddy wastewater is concentrated and filtered through a membrane concentration tank to obtain a filtrate and a concentrated slurry, and the concentrated slurry is filtered and washed to obtain vanadium-chromium sludge; The purified solution and the filtrate are input into a mixed system and sent to an evaporation concentration device for treatment to obtain anhydrous sodium sulfate.

2. The method for treating vanadium electrolyte production wastewater according to claim 1, characterized in that: The micro-reduction and neutralization precipitation treatment comprises: Under aeration, add reducing agent at 0.5% to 1.0% of the total mass of vanadium and chromium, react for 5 to 10 minutes, add alkaline solution to adjust the pH to 7.2 to 7.5, adjust the aeration volume and continue to react for 30 to 45 minutes to make the concentration of vanadium and chromium less than 0.5 mg / L. At the same time, make the organic matter containing extractant and oil suspended in the wastewater float to the surface and let it stand for 1 to 1.5 hours.

3. The method for treating vanadium electrolyte production wastewater according to claim 2, characterized in that: The microbubble reactor is a TV-type high-efficiency dissolved gas system.

4. The method for treating vanadium electrolyte production wastewater according to claim 3, characterized in that: The reducing agent is any combination of sodium pyrosulfite and sodium thiosulfate.

5. The method for treating vanadium electrolyte production wastewater according to claim 1, characterized in that: The clear liquid containing organic matter is subjected to catalytic oxidation treatment in a high potential catalytic oxidation reaction tank to obtain a purified solution, including: The stirring speed of the high-potential catalytic oxidation reaction tank is 300-360 rpm, and the degradation time is 30-45 min.

6. The method for treating vanadium electrolyte production wastewater according to claim 5, characterized in that: The high potential catalytic oxidation reaction tank adopts a boron-doped diamond BDD electrode with a high oxidation potential, an oxidation potential of 2.8V, an electrode spacing of 0.3-0.5cm, an operating voltage of 2-4V controlled by a voltage-stabilized power supply, and a current density of 5-10mA / cm 2 .

7. The method for treating vanadium electrolyte production wastewater according to claim 1, characterized in that: The membrane concentration tank comprises a flat membrane filtration concentration tank.

8. The method for treating vanadium electrolyte production wastewater according to claim 7, characterized in that: The flat membrane filtration and concentration tank is compressed by a silicon carbide ceramic membrane, with a filtration pore size of 0.5 to 1 um and a filtration pressure of 0.05 to 0.1 MPa.

9. The method for treating vanadium electrolyte production wastewater according to claim 8, characterized in that: The plate and frame filter is a fully automatic filter washing machine with a filtration accuracy of 5 to 8 um.

10. The method for treating vanadium electrolyte production wastewater according to claim 1, characterized in that: The purified solution and the filtrate are mixed and sent to an evaporation concentration device for treatment to obtain anhydrous sulfuric acid, including: During the treatment process, the stirring speed is 160-200 rpm and the evaporation temperature is 95-105°C.

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