An electrochemically coupled membrane distillation device, and a waste lithium battery wet recovery distillation system using the membrane distillation device and a method of using the same

Abstract

The present invention relates to the technical field of waste lithium battery recycling, specifically an electrochemically coupled membrane distillation device, and a waste lithium battery wet recovery distillation system and a method of use using the membrane distillation device, comprising a reaction mechanism, a conductive mechanism, a cover mechanism and an aeration mechanism; the reaction mechanism comprises a raw material reaction plate, an anode reaction plate and a permeation plate; the electrochemically coupled membrane distillation device disclosed in the present invention can perform in-situ electrochemical reactions on the surface of a conductive distillation membrane, thereby increasing the concentration rate of the solution and creating an alkaline environment; in-situ heating of the raw material liquid and utilization of industrial waste heat are achieved by introducing high-temperature CO2 gas into the raw material reaction plate; the alkaline environment of the solution absorbs and captures the CO2 gas and produces high-quality Li2CO3 solid; that is, the electrochemically coupled membrane distillation device disclosed in the present invention can not only produce high-quality Li2CO3 solid, but also absorb and capture industrial waste gas and waste heat.

Description

Technical Field

[0001] The present invention relates to the technical field of waste lithium battery recycling, and in particular to an electrochemically coupled membrane distillation device, and a waste lithium battery wet recovery distillation system and a method of using the membrane distillation device. Background Art

[0002] Global climate change has intensified over the past few decades, making it imperative to find efficient and environmentally friendly ways to produce energy and reduce CO2 emissions.

[0003] Lithium batteries are widely used in electric vehicles and energy storage systems, and play an important role in the field of renewable energy.

[0004] However, the total amount of lithium mineral resources is limited, and the production of lithium batteries still results in significant carbon emissions (for example, a large amount of CO2 will be produced during the calcination of Li2CO3 and FePO4).

[0005] In summary, the development of efficient recycling technology for waste lithium batteries and CO2 capture technology during the lithium battery production process will become the focus of future research and development.

[0006] During the acid release process of the positive electrode materials recovered from retired batteries, a large amount of medium and low concentration LiCl solution is often obtained, from which Li2CO3 needs to be recovered by concentration, pH adjustment, addition of Na2CO3, etc.

[0007] For example, patent: 201580049244.1 - Method for recycling positive electrode materials of lithium-ion batteries.

[0008] However, the energy consumption and chemical reagent usage in the above process do not meet the current environmental protection goals.

[0009] Therefore, in order to improve or solve the above problems, it is necessary to optimize the design of existing waste battery lithium ion recovery methods, processes or equipment. Summary of the Invention

[0010] The purpose of the present invention is to provide an electrochemically coupled membrane distillation device that can reduce industrial carbon emissions and recover lithium ions from waste batteries.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is:

[0012] An electrochemical coupled membrane distillation device comprises a reaction mechanism, a conductive mechanism, a cover mechanism and an aeration mechanism;

[0013] The reaction mechanism includes a raw material reaction plate, an anode reaction plate and a permeation plate;

[0014] The raw material reaction plate is provided with a raw material liquid channel;

[0015] The anode reaction plate is provided with an anode water flow channel;

[0016] The permeate plate is provided with a permeate side channel;

[0017] The cover plate mechanism includes an anode side cover plate and a permeate side cover plate;

[0018] The anode side cover plate, anode reaction plate, raw material reaction plate, permeate plate and permeate side cover plate are arranged in sequence;

[0019] The conductive mechanism includes a conductive distillation membrane and an electrode plate;

[0020] The conductive distillation membrane is arranged in the area between the permeation plate and the raw material reaction plate; the electrode plate is arranged in the area between the anode side cover plate and the anode reaction plate;

[0021] An anion exchange membrane is provided between the anode reaction plate and the raw material reaction plate;

[0022] The aeration mechanism includes an aeration plate arranged in the raw material liquid channel, and the aeration plate is connected to an air supply component.

[0023] The air supply component includes an air supply pipeline connected to the aeration plate, and high-temperature industrial flue gas containing CO2 is supplied into the air supply pipeline.

[0024] The high-temperature industrial flue gas is the high-temperature industrial flue gas generated during the preparation of LFP by calcining Li2CO3.

[0025] The aeration plate is made of foamed titanium; the high-temperature industrial flue gas is high-temperature CO2 gas with a temperature of 90-200°C, and the flow rate of the high-temperature industrial flue gas is set in proportion to the area of ​​the conductive distillation membrane.

[0026] A distillation system, comprising an electrochemically coupled membrane distillation device; the electrochemically coupled membrane distillation device is connected to a material system and a power supply mechanism;

[0027] The material system includes a raw material supply mechanism, an anolyte supply mechanism, a chlorine treatment mechanism and a water recovery mechanism;

[0028] The raw material supply mechanism, the anolyte supply mechanism, the chlorine treatment mechanism and the water recovery mechanism are respectively connected to the electrochemical coupling membrane distillation device through pipeline mechanisms.

[0029] The power supply mechanism includes a programmable power supply, which is connected to a conductive mechanism in an electrochemically coupled membrane distillation device; the positive electrode of the programmable power supply is connected to an electrode plate, and the negative electrode of the programmable power supply is connected to a conductive distillation membrane.

[0030] The raw material supply mechanism includes a raw material liquid water pump and a raw material liquid pool; the raw material liquid water pump is connected to the raw material liquid pool; the raw material liquid water pump and the raw material liquid pool are connected to the raw material reaction plate in the electrochemical coupled membrane distillation device through a pipeline mechanism;

[0031] The anolyte supply mechanism includes an anode pool and an anolyte water pump, wherein the anode pool is connected to the anolyte water pump; the anolyte water pump and the anode pool are respectively connected to the anode reaction plate in the electrochemical coupled membrane distillation device through a pipeline mechanism;

[0032] The chlorine treatment mechanism includes a chlorine absorption tank; the chlorine absorption tank is connected to the anode reaction plate through a pipeline mechanism;

[0033] The water recovery mechanism comprises a water pool; the water pool is connected to the permeation plate through a pipeline mechanism.

[0034] The raw material liquid water pump is connected in series with the raw material liquid pool; a solid-liquid separator is provided between the raw material liquid water pump and the raw material liquid pool.

[0035] The anode cell contains a saturated LiCl solution.

[0036] A method for using the distillation system, comprising the following steps:

[0037] Step 1: Assemble the entire distillation system and ensure that each mechanism can be used normally;

[0038] Step 2: After step 1 is completed, the raw material liquid to be processed is supplied to the raw material reaction plate through the raw material supply mechanism; the saturated LiCl solution is supplied to the anode reaction plate through the anode liquid supply mechanism; the power supply mechanism is turned on and supplies power to the conductive mechanism; the aeration mechanism continuously supplies air to the raw material reaction plate;

[0039] Step 3: Continue with step 2 to process the raw material liquid until the set requirements are met.

[0040] The advantages of the present invention are:

[0041] The invention discloses an electrochemical coupled membrane distillation device, a distillation system having the distillation device and a use method thereof.

[0042] The electrochemically coupled membrane distillation device disclosed in the present invention can carry out in-situ electrochemical reactions on the surface of the conductive distillation membrane, thereby improving the concentration rate of the solution and creating an alkaline environment. By introducing high-temperature CO2 gas into the raw material reaction plate, in-situ heating of the raw material liquid and utilization of industrial waste heat are achieved. The alkaline environment of the solution absorbs and captures the CO2 gas and produces high-quality Li2CO3 solid. In other words, the electrochemically coupled membrane distillation device disclosed in the present invention can not only produce high-quality Li2CO3 solid, but also absorb and capture industrial waste gas and waste heat.

[0043] The distillation system disclosed in the present invention can realize the treatment of raw material liquid in a cycle. In addition, the present invention utilizes high-temperature flue gas rich in CO2 to heat the raw material liquid of the membrane distillation system, and with the help of the electrochemical reaction on the surface of the conductive membrane material, absorbs CO2 without adding additional chemical reagents, concentrates the LiCl raw material liquid, and produces battery-grade Li2CO3; it simultaneously realizes the utilization of industrial waste heat, the capture of CO2, and the recovery of lithium resources in wastewater, and solves the problem that the membrane flux of the membrane distillation system decreases with the increase of the concentration multiple. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The following is a brief description of the contents and symbols in the drawings of the present invention:

[0045] Figure 1 System structure diagram of the distillation system of the present invention;

[0046] Figure 2 This is a diagram of the assembly method of the electrochemical coupled membrane distillation device;

[0047] Figure 3 It is a cross-sectional view of an electrochemically coupled membrane distillation device;

[0048] The marks in the above figure are:

[0049] Among them, 01-electrochemical coupled membrane distillation device, 02-aeration mechanism, 03-raw liquid tank, 04-solid-liquid separator, 05-raw liquid water pump, 06-anode tank, 07-anode liquid water pump, 08-chlorine absorption tank, 09-condenser, 10-water liquid tank, 11-vacuum pump, 12-programmable power supply.

[0050] 01-1-Raw material reaction plate, 01-2-Conductive distillation membrane, 01-3-Permeation plate, 01-4-Permeation side cover plate, 01-5-Anion exchange membrane, 01-6-Anode reaction plate, 01-7-Electrode, 01-8-Anode side cover plate, 01-9-Anode side water pipe, 01-10-Raw material liquid water pipe, 01-11-Gas supply pipe, 01-12-Permeation side pipe, 01-61, Anode water flow channel, 01-13, Raw material liquid channel, 01-31, Permeation side channel. DETAILED DESCRIPTION

[0051] The specific implementation of the present invention will be further explained in detail below by describing the best embodiment with reference to the accompanying drawings.

[0052] An electrochemically coupled membrane distillation device 01 includes a reaction mechanism, a conductive mechanism, a cover mechanism and an aeration mechanism 02; the electrochemically coupled membrane distillation device 01 disclosed in the present invention can perform in-situ electrochemical reactions on the surface of the conductive distillation membrane 01-2, thereby improving the concentration rate of the solution and creating an alkaline environment. By introducing high-temperature CO2 gas into the raw material reaction plate 01-1, in-situ heating of the raw material liquid and utilization of industrial waste heat are achieved. The alkaline environment of the solution absorbs and captures the CO2 gas and produces high-quality Li2CO3 solid; that is, the electrochemically coupled membrane distillation device 01 disclosed in the present invention can not only produce high-quality Li2CO3 solid; it can also absorb and capture industrial waste gas and waste heat.

[0053] The electrochemically coupled membrane distillation device 01 disclosed in the present invention can capture CO2 gas through electrochemical reaction, and can also separate Li ions in the LiCl solution formed after acid release and extraction of the positive electrode material of the lithium ion battery; thereby forming Li2CO3 precipitation.

[0054] Specifically, the reaction mechanism disclosed in the present invention includes a raw material reaction plate 01-1, an anode reaction plate 01-6 and a permeation plate 01-3; in the present invention, the raw material reaction plate 01-1 is used for the raw material liquid and CO2 gas to enter and the subsequent reaction between the two; and the anode reaction plate 01-6 is used for the anode water to flow in, which is convenient for the subsequent Cl - Under the action of the electric field, it migrates across the anion exchange membrane 01-5 to the anode water flow channel 01-61; finally, Cl2 is formed in the anode reaction plate 01-6, and then the Cl in the LiCl raw material solution is reduced. - It is removed and recovered in the form of Cl2; in addition, the setting of the permeation plate 01-3 of the present invention is mainly to facilitate the evaporation and discharge of water during the distillation process, thereby avoiding a significant increase in the ion concentration of the raw material liquid in actual production, and at the same time, the membrane flux of the membrane material can also be maintained at a high state.

[0055] In addition, in the present invention, the raw material reaction plate 01-1 is provided with a raw material liquid channel 01-13; the anode reaction plate 01-6 is provided with an anode water flow channel 01-61; the permeation plate 01-3 is provided with a permeation side channel 01-31; the present invention uses the raw material liquid channel 01-13, the raw material liquid channel 01-13 is an internal cavity structure of the raw material reaction plate 01-1, mainly to provide an internal reaction space, to facilitate the collection and reaction of the raw material liquid and the high-temperature industrial flue gas rich in CO2 in the raw material reaction plate 01-1; and the anode reaction plate 01-6 is provided with an anode water flow channel 01-6 1. The anode water flow channel 01-61 forms a cavity structure inside the anode reaction plate 01-6, which facilitates the flow of the anode water flow channel 01-61 and the subsequent generation and discharge of Cl2; similarly, the permeate side channel 01-31 is also a plate inner cavity structure, which is mainly used for the discharge of water vapor, accelerating the concentration of the solution and the discharge of water vapor. In addition, in the actual production process; because the evaporation of water during the electrolysis reaction and membrane distillation process does not cause a significant increase in the ion concentration of the raw material liquid, the membrane material flux can therefore be maintained at a high state to avoid the accumulation of water vapor in the distillation device and the impact.

[0056] In addition, the cover plate mechanism in the present invention includes an anode side cover plate 01-8 and a permeate side cover plate 01-4; the anode side cover plate 01-8, anode reaction plate 01-6, raw material reaction plate 01-1, permeate plate 01-3 and permeate side cover plate 01-4 are distributed in sequence; the present invention facilitates the overall assembly and fixation of the distillation apparatus through the arrangement of the anode side cover plate 01-8 and the permeate side cover plate 01-4. During actual assembly, the anode side cover plate 01-8 and the permeate side cover plate 01-4 are at the outermost side of the distillation apparatus, and the above-mentioned anode side cover plate 01-8, anode reaction plate 01-6, raw material reaction plate 01-1, permeate plate 01-3 and permeate side cover plate 01-4 are connected by bolts. Of course, other connection methods can be selected as needed in actual use.

[0057] At the same time, the conductive mechanism described in the present invention includes a conductive distillation membrane 01-2 and an electrode plate 01-7; in the present invention, through the above design, the basic purpose is to realize the connection between the distillation device and the power supply mechanism, to facilitate the power-on operation during subsequent use, and then to realize the electrolysis operation of the solution. At the same time, the conductive mechanism disclosed in the present invention has a conductive distillation mold on one side. In addition to the basic conductive function, the conductive distillation membrane 01-2 is also used for the subsequent distillation and evaporation of water.

[0058] In actual arrangement, the conductive distillation membrane 01-2 is required to be arranged between the permeation plate 01-3 and the raw material reaction plate 01-1; the electrode plate 01-7 is arranged between the anode side cover plate 01-8 and the anode reaction plate 01-6; through such an arrangement, both the anode water and the raw material liquid can be electrolyzed; at the same time, an anion exchange membrane 01-5 is provided between the anode reaction plate 01-6 and the raw material reaction plate 01-1; the anion exchange membrane 01-5 is used here; the Cl in the raw material liquid can be electrolyzed. - transfer, because under the action of electrochemical reaction, Cl - Converted into Cl2 and enters the chlorine absorption tank 08 to be recovered, and the Cl in the solution in the anode water flow channel 01-61 - The concentration of Cl decreases - The concentration decreases, and under the action of the electric field, the Cl in the raw liquid channel 01-13 - Passing through the anion exchange membrane 01-5 to replenish the anode water flow channel 01-61.

[0059] At the same time, the aeration mechanism 02 in the present invention includes an aeration plate arranged in the raw material liquid channel 01-13, and the aeration plate is connected to a gas supply component; the aeration mechanism 02 disclosed in the present invention is mainly used to supply gas to the raw material reaction plate 01-1, and the supplied gas is high-temperature carbon dioxide gas. One function of the high-temperature carbon dioxide gas is to heat the raw material liquid, and the other function is to supply carbonate ions to facilitate the subsequent combination with lithium ions to form Li2CO3 precipitation.

[0060] In summary, through the setting of the above-mentioned distillation device, the collection and separation of lithium ions in the raw material liquid can be achieved, and at the same time, the high-temperature waste gas generated by industrial production can be reused. It can not only reduce the impact of industrial waste gas on the air, but also utilize the waste heat of industrial waste gas to achieve secondary utilization of waste heat; in other words, the distillation device disclosed in the present invention not only helps to improve the efficiency of the lithium battery recycling process, but also greatly reduces CO2 emissions in the lithium battery production process, and contributes to the global response to climate change.

[0061] Furthermore, the air supply component in the present invention includes an air supply pipe 01-11 connected to the aeration plate. The air supply component is mainly configured to supply air to the aeration plate. In actual design, the air supply component includes an air supply pipe 01-11 connected to the aeration plate. The air supply pipe 01-11 can be directly connected to the industrial waste gas exhaust pipe, or can be connected to the industrial waste gas exhaust pipe through an air supply pump or other air supply equipment; the main purpose is to supply the required gas to the aeration plate; in addition, in specific implementation, it is required that high-temperature industrial flue gas containing CO2 is supplied in the air supply pipe 01-11; the high-temperature industrial flue gas containing CO2 here refers to high-temperature industrial flue gas rich in CO2; because the distillation device disclosed in the present invention not only utilizes the waste heat of the exhaust gas, but also mainly avoids the discharge of CO2 in the exhaust gas, and at the same time uses CO2 to form carbonate ions, which is convenient for subsequent combination with lithium ions to form Li2CO3 precipitation.

[0062] Furthermore, the high-temperature industrial flue gas described in the present invention is the high-temperature industrial flue gas generated during the preparation of LFP by calcining Li2CO3; here, the secondary utilization of the waste heat of the exhaust gas during the production of lithium batteries can be achieved, while avoiding the large amount of carbon dioxide generated from being discharged to cause the greenhouse effect; in other words, the present invention can significantly reduce the carbon emissions in the lithium battery production process through the above-mentioned utilization of the high-temperature industrial flue gas generated during the preparation of LFP by calcining Li2CO3, which can not only reduce the subsequent waste gas treatment costs, but also help to improve the efficiency of the lithium battery recycling process; and can also contribute to the global response to climate change; it has excellent social promotion significance.

[0063] Of course, in actual production, it is best to ensure the carbon dioxide content in high-temperature industrial flue gas and reduce the presence of gas as much as possible, so it can be used in conjunction with actual gas treatment equipment to make the treated waste gas richer in carbon dioxide and reduce or avoid other gases.

[0064] Furthermore, in the present invention, the aeration plate is made of foamed titanium; the high-temperature industrial flue gas is high-temperature CO2 gas with a temperature of 90-200 ° C, and the flow rate of the high-temperature industrial flue gas is set in proportion to the area of ​​the conductive distillation membrane 01-2; in the present invention, microporous structure materials such as foamed titanium are used to achieve micron-level bubble generation and uniform distribution, and the bubble size range is 20-100 μm. The industrial flue gas introduced therein is high-temperature CO2 gas with a temperature of 90-200 ° C, and the flow rate is related to the area of ​​the conductive distillation membrane 01-2 and is set to 0.1-5 m 3 二氧化碳 / (m 2 膜材料·min); adopting the above design ratio can avoid excessive or insufficient supply of high-temperature CO2 gas in the raw material reaction plate 01-1; thereby avoiding the accumulation of too many ions in the raw material liquid; and also avoid the presence of too few carbonate ions that affect the separation of lithium ions.

[0065] A distillation system includes an electrochemically coupled membrane distillation device 01; the electrochemically coupled membrane distillation device 01 is connected to a material system and a power supply mechanism. In addition, the distillation system disclosed in the present invention can circulate and process the raw liquid. In addition, the present invention utilizes high-temperature flue gas rich in CO2 to heat the raw liquid of the membrane distillation system, and uses the electrochemical reaction on the surface of the conductive membrane material to absorb CO2 without adding additional chemical reagents, concentrate the LiCl raw liquid, and produce battery-grade Li2CO3. The system simultaneously realizes the utilization of industrial waste heat, the capture of CO2, and the recovery of lithium resources in wastewater, and solves the problem that the membrane flux of the membrane distillation system decreases with the increase of the concentration factor.

[0066] Specifically, the material system described in the present invention includes a raw material supply mechanism, an anode liquid supply mechanism, a chlorine treatment mechanism and a water recovery mechanism; in the present invention, the raw material supply mechanism is mainly used to supply the raw material liquid, so that the raw material liquid continues to flow in the raw material reaction plate 01-1; at the same time, the anode liquid supply mechanism is mainly used to supply the anode water, so that the anode liquid continues to flow and supply in the anode reaction plate 01-6; the chlorine treatment mechanism is mainly used to collect the chlorine discharged from the anode plate to avoid the overflow of chlorine, and the water recovery mechanism is mainly used to collect the water vapor discharged from the permeation plate 01-3 to avoid its overflow.

[0067] At the same time, in the present invention, the raw material supply mechanism, the anolyte supply mechanism, the chlorine treatment mechanism and the water recovery mechanism are respectively connected to the electrochemically coupled membrane distillation device 01 through a pipeline mechanism; the setting of the pipeline mechanism here facilitates the connection between each mechanism and the electrochemically coupled membrane distillation device 01. The pipeline mechanism is mainly a pipeline structure, and a valve body can be set on the pipeline structure. The valve body can be a solenoid valve or other control valve body structure. The valve body mainly controls the on and off of the pipeline mechanism. At the same time, the length and size of the above-mentioned pipeline mechanism are selected according to needs; the setting of the pipeline mechanism facilitates the dispersed arrangement of each mechanism, and facilitates multiple distillation devices to share a set of the above-mentioned material system in actual production.

[0068] Furthermore, the power supply mechanism in the present invention includes a programmable power supply 12, which is connected to the conductive mechanism in the electrochemical coupled membrane distillation device 01; the positive electrode of the programmable power supply 12 is connected to the electrode plate 01-7, and the negative electrode of the programmable power supply 12 is connected to the conductive distillation membrane 01-2; the present invention uses a programmable power supply 12; its output voltage can be intelligently controlled between 1.2-30 V according to parameters such as system current density, solution conductivity, and solution pH, thereby ensuring a good concentration rate, Li2CO3 yield, and H2 purity; and has excellent practical use effects.

[0069] Furthermore, in the present invention, the raw material supply mechanism includes a raw material liquid water pump 05 and a raw material liquid pool 03; the raw material liquid water pump 05 is connected to the raw material liquid pool 03; the raw material liquid water pump 05 and the raw material liquid pool 03 are connected to the raw material reaction plate 01-1 in the electrochemical coupled membrane distillation device 01 through a pipeline mechanism; through the above design, it is convenient for the raw material liquid water pump 05 to pump the raw material liquid in the raw material liquid pool 03 during subsequent use, so that the raw material liquid enters or discharges the raw material reaction plate 01-1.

[0070] Similarly; the anolyte supply mechanism includes an anode pool 06 and an anode liquid water pump 07, and the anode pool 06 is connected to the anode liquid water pump 07; the anode liquid water pump 07 and the anode pool 06 are respectively connected to the anode reaction plate 01-6 in the electrochemical coupled membrane distillation device 01 through a pipeline mechanism; the present invention is convenient for subsequent use through the above design, and the anode liquid water pump 07 controls the anode liquid in the anode pool 06, which facilitates the entry or discharge of the anode liquid in the anode reaction plate 01-6.

[0071] The chlorine treatment mechanism includes a chlorine absorption tank 08; the chlorine absorption tank 08 is connected to the anode reaction plate 01-6 through a pipeline mechanism; the chlorine absorption tank 08 is mainly used to store dichloromethane or sodium hydroxide, which facilitates the subsequent absorption and recovery of chlorine.

[0072] The water recovery mechanism in the present invention comprises a water pool 10; the water pool 10 is connected to the permeation plate 01-3 through a pipeline mechanism; the water pool 10 is used to recover water vapor, and in order to ensure the recovery effect, a condenser 09 is arranged in front of the water pool 10.

[0073] Furthermore, in the present invention, the raw liquid water pump 05 is connected in series with the raw liquid pool 03; a solid-liquid separator 04 is provided between the raw liquid water pump 05 and the raw liquid pool 03; the present invention can separate Li2CO3 precipitation through the setting of the solid-liquid separator 04; the liquid continues to enter the raw liquid pool 03 for the next electrochemical distillation treatment operation.

[0074] Furthermore, in the present invention, the anode tank 06 contains a saturated LiCl solution; this solution can prevent the Cl2 generated by the electrode plate 01-7 from re-dissolving in the solution, thereby facilitating the recovery of Cl2 and protecting the anion exchange membrane 01-5.

[0075] A method for using the distillation system, comprising the following steps:

[0076] Step 1: Assemble the entire distillation system and ensure that each mechanism can be used normally;

[0077] Step 2: After step 1 is completed, the raw material liquid to be processed is supplied to the raw material reaction plate 01-1 through the raw material supply mechanism; the saturated LiCl solution is supplied to the anode reaction plate 01-6 through the anode liquid supply mechanism; the power supply mechanism is turned on and supplies power to the conductive mechanism; the aeration mechanism 02 continuously supplies air to the raw material reaction plate 01-1;

[0078] Step 3: Continue with step 2 to process the raw material liquid until the set requirements are met.

[0079] Through the disclosure of the above-mentioned method of use, the present invention can realize multiple repeated treatments of the raw material liquid by continuously running step 2, thereby ensuring sufficient separation of lithium ions in the raw material liquid.

[0080] specific:

[0081] During the acid release process of the positive electrode materials recovered from retired batteries, a large amount of medium and low concentration LiCl solution is often obtained, from which Li2CO3 needs to be recovered by concentration, pH adjustment, addition of Na2CO3, etc.

[0082] The energy consumption and chemical reagent usage required for normal processing of this process do not meet current environmental protection goals.

[0083] The present invention uses membrane distillation technology as a basis and discloses a novel separation device and separation method, which has the advantages of high concentration ratio, utilization of low-grade energy, simple device structure, and low incidence of membrane pollution and scaling.

[0084] At the same time, the present invention installs a conductive distillation membrane 01-2 and couples the electrochemical reaction in situ; it can overcome the problems of the membrane distillation system being unable to achieve chemical component conversion and flux reduction after high-fold concentration, and by utilizing industrial flue gas (such as high-temperature CO2 generated by calcination in the production process of lithium batteries) for in-situ heating, it improves energy utilization efficiency while achieving CO2 capture.

[0085] Therefore, this device not only helps to improve the efficiency of the lithium battery recycling process, but also greatly reduces CO2 emissions during the lithium battery production process, contributing to the global fight against climate change.

[0086] In the present invention, in response to the problems existing in the prior art, a high-quality conductive distillation membrane 01-2 is prepared, and an electrochemically coupled membrane distillation device 01 and an operating mode for simultaneously achieving lithium carbonate production and carbon dioxide capture are designed.

[0087] The in-situ electrochemical reaction on the surface of the conductive distillation membrane 01-2 increases the concentration rate of the solution and creates an alkaline environment. By introducing high-temperature CO2 gas into the membrane distillation device, in-situ heating of the raw liquid and utilization of industrial waste heat are achieved. At the same time, the alkaline environment of the solution absorbs and captures the CO2 gas, producing high-quality Li2CO3 solid.

[0088] The specific technical solutions are:

[0089] An electrochemically coupled membrane distillation device 01 and a distillation system.

[0090] The distillation device mainly includes a reaction mechanism, a conductive mechanism, a cover mechanism and an aeration mechanism 02; the reaction mechanism includes a raw material reaction plate 01-1, an anode reaction plate 01-6 and a permeation plate 01-3; the raw material reaction plate 01-1 is provided with a raw material liquid channel 01-13; the anode reaction plate 01-6 is provided with an anode water flow channel 01-61; the permeation plate 01-3 is provided with a permeation side channel 01-31; the cover mechanism includes an anode side cover plate 01-8 and a permeation side cover plate 01-4; the anode side cover plate 01-8, the anode reaction plate 01-6, the raw material reaction plate 01-1, The permeation plate 01-3 and the permeation side cover plate 01-4 are distributed in sequence; the conductive mechanism includes a conductive distillation membrane 01-2 and an electrode plate 01-7; the conductive distillation membrane 01-2 is arranged in the area between the permeation plate 01-3 and the raw material reaction plate 01-1; the electrode plate 01-7 is arranged in the area between the anode side cover plate 01-8 and the anode reaction plate 01-6; an anion exchange membrane 01-5 is provided between the anode reaction plate 01-6 and the raw material reaction plate 01-1; the aeration mechanism 02 includes an aeration plate arranged in the raw liquid channel 01-13, and the aeration plate is connected to an air supply component.

[0091] specific;

[0092] The distillation system includes an electrochemical coupled membrane distillation device 01, an aeration mechanism 02, a raw liquid tank 03, a solid-liquid separator 04, a raw liquid water pump 05, an anode tank 06, an anode liquid water pump 07, a chlorine absorption tank 08, a condenser 09, a water liquid tank 10, a vacuum pump 11, and a programmable power supply 12.

[0093] Among them, Figure 2 and Figure 3As shown, the electrochemical coupled membrane distillation device 01 includes a raw liquid channel 01-13, a conductive distillation membrane 01-2, a vacuum permeation side channel 01-31, a permeation side cover plate 01-4, an anion exchange membrane 01-5, an anode water flow channel 01-61, an electrode plate 01-7, and an anode side cover plate 01-8.

[0094] The pipeline mechanism connected to the anode reaction plate 01-6 of the present invention mainly includes the anode side water pipe 01-9, which is used for the supply of anode liquid; the pipeline mechanism connected to the raw material reaction plate 01-1 mainly includes the raw liquid water pipe 01-10, which is mainly used for the supply of raw liquid to the raw material reaction plate; the gas supply pipeline 01-11 is mainly used for the supply of high-temperature industrial gas in the raw material reaction plate; the pipeline mechanism connected to the permeation plate 01-3 includes the permeation side pipeline 01-12.

[0095] The preparation method of the conductive distillation membrane 01-2 is as follows: a conductive coating is loaded on the surface of the hydrophobic PTFE membrane by vacuum-driven self-assembly to obtain the conductive distillation membrane 01-2.

[0096] Specifically, the PTFE hydrophobic membrane is moistened with ethanol, and then an aqueous solution containing graphene, silver nanowires, metal organic framework particles and polyvinyl alcohol crosslinker is filtered at a negative pressure of 0.1-0.4 Bar, so that the components in the water are retained on the surface of the membrane material and self-assembled into a conductive layer with a thickness of 50-200 nm.

[0097] The electrode plate 01-7 is selected from titanium electrode plate 01-7, ruthenium-iridium electrode plate 01-7 or platinum electrode plate 01-7.

[0098] Aeration mechanism 02 uses microporous structural materials such as titanium foam to achieve micron-level bubble generation and uniform distribution, with bubble size ranging from 20-100 μm. The industrial flue gas introduced into it is high-temperature CO2 gas with a temperature of 90-200 ℃. The flow rate is related to the area of ​​conductive distillation membrane 01-2 and is set to 0.1-5 m 3 二氧化碳 / (m 2 膜材料 ·min).

[0099] The raw liquid pool 03 contains a low-concentration LiCl solution, which is the product of acid release and extraction of lithium-ion battery positive electrode materials, with a concentration range of 20-400 mmol / L.

[0100] The anode tank 06 contains a saturated LiCl solution, which can prevent the Cl2 generated by the electrode plate 01-7 from re-dissolving in the solution, thereby facilitating the recovery of Cl2 and protecting the anion exchange membrane 01-5.

[0101] The chlorine absorption tank 08 is filled with dichloromethane or sodium hydroxide to absorb and recover Cl2.

[0102] The positive electrode of the programmable power supply 12 is connected to the electrode plate 01-7 in the electrochemically coupled membrane distillation device 01, and the negative electrode is connected to the conductive distillation membrane 01-2 in the electrochemically coupled membrane distillation device 01. Its output voltage can be intelligently controlled between 1.2-30 V according to parameters such as system current density, solution conductivity, and solution pH, thereby ensuring a good concentration rate, Li2CO3 yield, and H2 purity.

[0103] This device includes three channels of mass transfer reactions, and the three reactions are carried out simultaneously, as follows:

[0104] Anode channel reaction R1: The saturated LiCl solution in the anode cell 06 flows into the anode water flow channel 01-61 of the electrochemical coupled membrane distillation device 01 under the action of the anode liquid pump 07. Under the action of the electrochemical reaction, Cl - Converted into Cl2 and enters the chlorine absorption tank 08 to be recovered, and the Cl in the solution in the anode water flow channel 01-61 - The concentration decreases, and under the action of the electric field, the Cl in the raw liquid channel 01-13 - It passes through the anion exchange membrane 01-5 and is replenished to the anode water flow channel 01-61 to maintain the saturation of LiCl, and finally the solution flows back to the anode tank 06.

[0105] Raw liquid channel 01-13 reaction R2: The low- to medium-concentration LiCl solution in the raw liquid pool 03 flows into the raw liquid channel 01-13 of the electrochemically coupled membrane distillation device 01 under the action of the raw liquid water pump 05, and forms a LiOH solution under the action of the electrochemical reaction; the solution is heated by the high-temperature CO2, and the liquid water therein evaporates into water vapor, which enters the vacuum permeation side channel 01-31 under the action of negative pressure; at the same time, LiOH reacts with CO2 to form Li2CO3 precipitate, which flows out of the electrochemically coupled membrane distillation device 01 with the water flow, enters the solid-liquid separator 04 and is recovered, and the remaining solution returns to the raw liquid pool 03.

[0106] Reaction R3 of the permeation side channel 01-31: Under the action of the vacuum pump 11, the water vapor evaporated from the raw liquid channel 01-13, the unreacted CO2 and the H2 generated by the electrochemical reaction on the surface of the conductive distillation membrane 01-2 all pass through the conductive distillation membrane 01-2 into the vacuum permeation side channel 01-31 and are recovered.

[0107] In principle, the distillation system of the present invention undergoes both electrochemical reaction and membrane distillation reaction during operation; specifically, the following:

[0108] Electrochemical reaction part: Driven by the electrochemical reaction and electric field, Cl2 is generated on the surface of the electrode plate 01-7 and the Cl2 in the anode water flow channel 01-61 is reduced. -Concentration, Cl in raw liquid channel 01-13 - Under the action of the electric field, H2 is generated on the surface of the conductive distillation membrane 01-2, and OH is generated on the surface of the membrane material. - , forming an alkaline environment. At the same time, the electrolysis reaction consumes the liquid water in the raw material solution, and also accelerates the concentration of the solution to a certain extent.

[0109] Membrane distillation reaction part: The membrane distillation reaction uses temperature difference as the driving force, in which the higher water temperature in the raw liquid channel 01-13 comes from the combined effect of heat release from electrolysis of water and heating of industrial flue gas; through the aeration mechanism 02, the high-temperature industrial flue gas rich in CO2 (such as CO2 generated during the preparation of LFP by calcining Li2CO3) can in-situ heat the solution in the water flow channel; at the same time, as the solution concentrates, CO2 can dissolve in the liquid in an alkaline environment and react with Li + Combined to form Li2CO3 precipitation, and the separation of Li2CO3 is achieved through solid-liquid separator 04; In addition, Cl in LiCl raw material solution - Removed and recovered in the form of Cl2, Li + It is separated in the form of Li2CO3. Therefore, the electrolysis reaction of water and the evaporation of water during membrane distillation will not cause a significant increase in the ion concentration of the raw liquid, and the membrane flux of the membrane material can therefore be maintained at a high state.

[0110] This device includes three channels of mass transfer reactions, and the three reactions are carried out simultaneously. The specific implementation method is as follows:

[0111] Anode channel reaction R1: The saturated LiCl solution in the anode cell 06 flows into the anode water flow channel 01-61 of the electrochemical coupled membrane distillation device 01 under the action of the anode liquid pump 07. Under the action of the electrochemical reaction, Cl - Converted into Cl2 and enters the chlorine absorption tank 08 to be recovered, and the Cl in the solution in the anode water flow channel 01-61 - The concentration decreases, and under the action of the electric field, the Cl in the raw liquid channel 01-13 - It passes through the anion exchange membrane 01-5 and is replenished to the anode water flow channel 01-61 to maintain the saturation of LiCl, and the solution finally flows back to the anode tank 06.

[0112] Raw liquid channel 01-13 reaction R2: The low- to medium-concentration LiCl solution in the raw liquid pool 03 flows into the raw liquid channel 01-13 of the electrochemically coupled membrane distillation device 01 under the action of the raw liquid water pump 05, and forms a LiOH solution under the action of the electrochemical reaction; the solution is heated by the high-temperature CO2, and the liquid water therein evaporates into water vapor, which enters the vacuum permeation side channel 01-31 under the action of negative pressure; at the same time, LiOH reacts with CO2 to form Li2CO3 precipitate, which flows out of the electrochemically coupled membrane distillation device 01 with the water flow, enters the solid-liquid separator 04 and is recovered, and the remaining solution returns to the raw liquid pool 03.

[0113] Reaction R3 of the permeation side channel 01-31: Under the action of the vacuum pump 11, the water vapor evaporated from the raw liquid channel 01-13, the unreacted CO2 and the H2 generated by the electrochemical reaction on the surface of the conductive distillation membrane 01-2 all pass through the conductive distillation membrane 01-2 into the vacuum permeation side channel 01-31 and are recovered.

[0114] The present invention discloses an electrochemically coupled membrane distillation device 01 and a distillation system; the distillation system disclosed in the present invention can simultaneously achieve lithium carbonate production and carbon dioxide capture.

[0115] The present invention utilizes high-temperature flue gas rich in CO2 to heat the raw liquid of the membrane distillation system, and with the help of the electrochemical reaction on the surface of the conductive membrane material, absorbs CO2 without adding additional chemical reagents, concentrates the LiCl raw liquid, and produces battery-grade Li2CO3.

[0116] At the same time, this technology simultaneously realizes the utilization of industrial waste heat, the capture of CO2, the recovery of lithium resources in wastewater, and solves the problem that the membrane flux of the membrane distillation system decreases with the increase of concentration multiples; it has excellent use effect.

[0117] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the scope of protection of the present invention.

Claims

1. An electrochemically coupled membrane distillation device, characterized in that: It includes a reaction mechanism, a conductive mechanism, a cover mechanism and an aeration mechanism; The reaction mechanism includes a raw material reaction plate, an anode reaction plate and a permeation plate; The raw material reaction plate is provided with a raw material liquid channel; The anode reaction plate is provided with an anode water flow channel; The permeate plate is provided with a permeate side channel; The cover plate mechanism includes an anode side cover plate and a permeate side cover plate; The anode side cover plate, anode reaction plate, raw material reaction plate, permeate plate and permeate side cover plate are arranged in sequence; The conductive mechanism includes a conductive distillation membrane and an electrode plate; The conductive distillation membrane is arranged in the area between the permeation plate and the raw material reaction plate; the electrode plate is arranged in the area between the anode side cover plate and the anode reaction plate; An anion exchange membrane is provided between the anode reaction plate and the raw material reaction plate; The aeration mechanism includes an aeration plate arranged in the raw liquid channel, and the aeration plate is connected to an air supply component; The electrode plate is connected to the positive electrode of the power supply, and the conductive distillation membrane is connected to the negative electrode of the power supply.

2. The electrochemically coupled membrane distillation device according to claim 1, characterized in that: The air supply component includes an air supply pipeline connected to the aeration plate, and high-temperature industrial flue gas containing CO2 is supplied into the air supply pipeline.

3. The electrochemically coupled membrane distillation device according to claim 2, characterized in that: The high-temperature industrial flue gas is the high-temperature industrial flue gas generated during the preparation of LFP by calcining Li2CO3.

4. The electrochemically coupled membrane distillation device according to claim 2, characterized in that: The aeration plate is made of foamed titanium; the high-temperature industrial flue gas is high-temperature CO2 gas with a temperature of 90-200°C, and the flow rate of the high-temperature industrial flue gas is set in proportion to the area of ​​the conductive distillation membrane.

5. A wet recovery distillation system for waste lithium batteries, characterized in that: Comprises an electrochemically coupled membrane distillation apparatus according to any one of claims 1-4; the electrochemically coupled membrane distillation apparatus is connected to a material system and a power supply mechanism; The material system includes a raw material supply mechanism, an anolyte supply mechanism, a chlorine treatment mechanism and a water recovery mechanism; The raw material supply mechanism, the anolyte supply mechanism, the chlorine treatment mechanism and the water recovery mechanism are respectively connected to the electrochemical coupling membrane distillation device through pipeline mechanisms.

6. A waste lithium battery wet recovery distillation system according to claim 5, characterized in that: The power supply mechanism includes a programmable power supply, which is connected to a conductive mechanism in an electrochemically coupled membrane distillation device; the positive electrode of the programmable power supply is connected to an electrode plate, and the negative electrode of the programmable power supply is connected to a conductive distillation membrane.

7. A waste lithium battery wet recovery distillation system according to claim 5, characterized in that: The raw material supply mechanism includes a raw material liquid water pump and a raw material liquid pool; the raw material liquid water pump is connected to the raw material liquid pool; the raw material liquid water pump and the raw material liquid pool are connected to the raw material reaction plate in the electrochemical coupled membrane distillation device through a pipeline mechanism; The anolyte supply mechanism includes an anode pool and an anolyte water pump, wherein the anode pool is connected to the anolyte water pump; the anolyte water pump and the anode pool are respectively connected to the anode reaction plate in the electrochemical coupled membrane distillation device through a pipeline mechanism; The chlorine treatment mechanism includes a chlorine absorption tank; the chlorine absorption tank is connected to the anode reaction plate through a pipeline mechanism; The water recovery mechanism comprises a water pool; the water pool is connected to the permeation plate through a pipeline mechanism.

8. A waste lithium battery wet recovery distillation system according to claim 7, characterized in that: The raw material liquid water pump is connected in series with the raw material liquid pool; a solid-liquid separator is provided between the raw material liquid water pump and the raw material liquid pool.

9. A waste lithium battery wet recovery distillation system according to claim 7, characterized in that: The anode cell contains a saturated LiCl solution.

10. A method for using the distillation system according to any one of claims 5 to 9, characterized in that: The method of use comprises the following steps: Step 1: Assemble the entire waste lithium battery wet recovery distillation system and ensure that each mechanism can be used normally; Step 2: After step 1 is completed, the raw material liquid to be processed is supplied to the raw material reaction plate through the raw material supply mechanism; the saturated LiCl solution is supplied to the anode reaction plate through the anode liquid supply mechanism; the power supply mechanism is turned on and supplies power to the conductive mechanism; the aeration component continuously supplies air to the raw material reaction plate; Step 3: Continue with step 2 to process the raw material liquid; Until the set requirements are met.

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