Method for removing impurities and treating waste positive electrode material from lithium batteries during recovery process

Abstract

The method for removing and treating impurities in the recovery process of waste lithium battery cathode material includes the steps of: controlling the flow rates of a leaching solution and a first alkaline solution from waste lithium battery cathode material at a first temperature higher than room temperature and at a constant first pH value to precipitate and remove iron ions, aluminum ions, and at least a portion of copper ions, thereby obtaining a first filtrate; controlling the flow rates of the first filtrate, a complexing agent, and a second alkaline solution at a second temperature higher than room temperature and at a constant first pH range to separate a second filtrate containing lithium ions, thereby obtaining a target substance precipitate; dissolving the target substance precipitate to obtain a first solution; and controlling the flow rates of the first solution and a fluorine-containing precipitant at a third temperature higher than room temperature and at a constant fluoride ion concentration to precipitate and remove calcium ions, magnesium ions, and at least a portion of lead ions, thereby obtaining a target solution. This method can obtain a precipitate with large particle size, high crystallinity, and low water content, and can be washed to improve the recovery rate of nickel, cobalt, and manganese from waste lithium battery cathode material.

Description

[Technical field]

[0001] Priority information This invention claims priority to Chinese Application No. 202011347197.8, filed on November 26, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the field of material recovery technology, and in particular to a method for removing and treating impurities in the recovery process of waste positive electrode materials of lithium batteries. [Background technology]

[0003] In the process of recovering discarded positive electrode materials from lithium batteries, the eluted nickel-cobalt-manganese solution often contains various metal impurities (e.g., Fe, Al, Cu, Ca, Mg, Pb, etc.). If the impurities are not removed, the above impurities will affect the quality and performance of the lithium battery positive electrode material synthesized after the recovery of the discarded positive electrode materials from lithium batteries.

[0004] In the prior art, the method for removing metal impurities such as Fe, Al, Ca, and Mg has the problem of difficult filtration and washing of precipitates, so that the precipitates of impurities that cannot be filtered remain in the actual filtrate, and the precipitates of impurities are mixed into the subsequent steps, so that the final impurity content in the ternary precursor product is high. In addition, because it is difficult to filter and wash the precipitates, the requirements for filtration equipment during filtration are high, the demand for washing water increases, and the filtration takes more time. In addition, some gel slag has a high liquid content, which is easy to cause clogging of the filter material, making washing impossible, making the filtering and washing operations more difficult, reducing the recovery rate of nickel-cobalt-manganese metals and increasing the recovery cost.

[0005] In addition, the co-precipitation process of the precursor of the ternary positive electrode material (or referred to as the ternary precursor) is an important process in the manufacture of the positive electrode material of the lithium battery. The performance of the precursor product directly affects the performance of the positive electrode material. The equipment for precursor co-precipitation is expensive and requires precise manufacturing, so the impact of improving the production efficiency of the precursor on the cost of the entire recovery process is particularly important. In the normal co-precipitation process of the ternary precursor, the pH value of the recovery process is precisely controlled by an online pH meter to ensure the quality of the precursor. The inventor's research is to solve the problem that in a solution with a high lithium ion concentration, the online pH meter is prone to cause lithium ion poisoning and affects the stability of the co-precipitation process. In addition, the use of sodium hydroxide as a precipitant greatly improves the production efficiency, reduces the amount of water used in the recovery process, and reduces the volume of the equipment. Due to the above two reasons, the present invention removes lithium ions before the co-precipitation process of the ternary precursor, and precipitates hydroxides of metals such as nickel, cobalt, and manganese, which are easily washed, by controlling the reaction conditions as long as they do not significantly affect the production efficiency of the recovery process. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there is a need to provide a method for removing and treating impurities in the recovery process of waste positive electrode materials of lithium batteries. [Means for solving the problem]

[0007] An embodiment of the present invention provides a method for removing and treating impurities in a process for recovering waste positive electrode materials of lithium batteries. The method includes the steps of (1) controlling the flow rates of the leaching solution and the first alkaline solution of the waste positive electrode materials of lithium batteries in a stable environment of a first temperature higher than room temperature and a constant first pH value to precipitate and remove iron ions, aluminum ions and at least a part of copper ions to obtain a first filtrate, (2) controlling the flow rates of the first filtrate, the complexing agent and the second alkaline solution to remove lithium ions at a second temperature higher than room temperature and a constant first pH range to separate a second filtrate containing lithium ions to obtain a target substance precipitate, (3) dissolving the target substance precipitate to obtain a first solution, and (4) controlling the flow rates of the first solution and the fluorine-containing precipitate to precipitate and remove calcium ions, magnesium ions and at least a part of lead ions at a third temperature higher than room temperature and a constant fluorine ion concentration to obtain a target solution. The impurity removal and treatment method is carried out in a continuously operable overflow reaction tank.

[0008] An embodiment of the present invention provides a method for removing impurities and treating waste positive electrode materials from lithium batteries in a recovery process. The method includes a first reaction Slot Add an appropriate amount of the first bottom liquid into the first reaction vessel. Slot maintaining a reaction temperature in the reaction chamber at a first temperature higher than room temperature; and supplying the leaching solution of the waste positive electrode material of the lithium battery and the first alkaline solution at appropriate flow rates, respectively, to the first reaction chamber. Slot The first reaction is then sucked in. Slot and overflowing the first alkaline solution from the first alkaline solution. During the first time period, the reaction is maintained at a stable first temperature and the flow rate of the first alkaline solution is adjusted to stably carry out the reaction at a first pH value. Thereafter, a first separation step is carried out to obtain a first impurity and a first filtrate.

[0009] In some embodiments, prior to performing the first separation step, the method further comprises: Slot The method further includes aging the overflow mixture from the thermostat while maintaining the aging temperature at the first temperature for a second time.

[0010] In some embodiments, the method further comprises: Slot Add an appropriate amount of the second bottom liquid into the second reaction vessel. Slot maintaining the reaction temperature within the reaction vessel at a second temperature above room temperature, and then Slot introducing a protective gas into the second reaction vessel; and feeding the first filtrate, the complexing agent and the second alkaline solution at appropriate flow rates, respectively, to the second reaction vessel. Slot After inhaling the mixture into the container and reacting for a third hour, Slot and overflowing the second alkaline solution from the second alkaline solution. During the third time, the reaction is maintained at the second temperature and the flow rate of the second alkaline solution is adjusted to stably carry out the reaction in a first pH range. Thereafter, a second separation step is carried out to obtain a target substance precipitate and a second filtrate. The second filtrate contains lithium ions.

[0011] In some embodiments, prior to performing the second separation step, the method further comprises: Slot The method further includes aging the overflow mixture from the thermostat while maintaining the aging temperature at the second temperature for a fourth period of time.

[0012] In some embodiments, the method includes dissolving the target substance precipitate to obtain a first solution, and reacting the target substance with a third solution. Slot maintaining a reaction temperature in the reaction vessel at a third temperature higher than room temperature; and feeding the first solution and the fluorine-containing precipitant to the third reaction vessel at appropriate flow rates, respectively. Slot After inhaling and reacting for 5 hours, Slot and overflowing the fluorine-containing precipitant from the third reaction vessel. Slot The fluorine ion concentration of the reactant in is stabilized within a first concentration range. Then, a third separation step is performed to obtain a second impurity and a target solution.

[0013] In some embodiments, prior to performing the third separation step, the method further comprises: Slotand aging the overflowed mixture for a sixth hour while maintaining the aging temperature at the third temperature, and allowing the aged mixture to stand for a seventh hour.

[0014] In some embodiments, the impurity removal method can continuously treat the leachate of the waste positive electrode material of the lithium battery.

[0015] In some embodiments, before subjecting the leachate of the waste lithium battery cathode material to a precipitation treatment, the method further comprises: adding a leachate including at least a reducing agent, a first acid, and water to the waste lithium battery cathode material to dissolve it until the pH is in a second range, and then performing a fourth separation step to obtain a third impurity and a leachate of the waste lithium battery cathode material, where the leachate includes at least a reducing agent, a first acid, and water.

[0016] In some embodiments, the lithium battery waste positive electrode material comprises one or more of a lithium nickel cobalt manganese oxide battery material, a lithium cobalt oxide battery material, a lithium cobalt manganese oxide battery material, a lithium cobalt alumina battery material, and a lithium manganese oxide battery material.

[0017] In some embodiments, the method further comprises adding a third alkaline solution to the target solution to obtain a precursor precipitate.

[0018] In some embodiments, the first bottom liquid is deionized water or a solution having a pH of the first pH value.

[0019] In some embodiments, the first temperature is anywhere between 50 and 90 degrees Celsius.

[0020] In some embodiments, the first alkaline solution comprises lithium hydroxide.

[0021] In some embodiments, the first pH value is any value between pH 5.5 and 6.7.

[0022] In some embodiments, the first period of time is between 2 and 10 hours.

[0023] In some embodiments, the first impurity comprises one or more of iron hydroxide, aluminum hydroxide, and copper hydroxide.

[0024] In some embodiments, the second period of time is between 0.5 and 2 hours.

[0025] In some embodiments, the second bottoms liquid comprises aqueous ammonia.

[0026] In some embodiments, the second temperature is anywhere between 40 and 70 degrees Celsius.

[0027] In some embodiments, the protective gas comprises nitrogen gas or an inert gas.

[0028] In some embodiments, the complexing agent comprises aqueous ammonia.

[0029] In some embodiments, the second alkaline solution comprises lithium hydroxide.

[0030] In some embodiments, the first pH range is pH=10.5-11.8.

[0031] In some embodiments, the third period of time is between 2 and 10 hours.

[0032] In some embodiments, the fourth period of time is between 0.5 and 2 hours.

[0033] In some embodiments, the step of dissolving the target substance precipitate to obtain a first solution includes the steps of adding a leaching agent into the target substance precipitate and dissolving until the pH is in a third range to obtain a solution containing the target substance, and adding an appropriate amount of a fourth alkaline solution to the solution containing the target substance until the pH is in a fourth range to obtain the first solution.

[0034] In some embodiments, the third range is pH=0-4.

[0035] In some embodiments, the fourth range is pH=4.5 to 6.5.

[0036] In some embodiments, the third temperature is any value between 50 and 90 degrees Celsius.

[0037] In some embodiments, the fluorine-containing precipitating agent comprises a sodium fluoride solution.

[0038] In some embodiments, the first concentration range is a fluoride ion concentration of 0.005 to 0.1 mol / L.

[0039] In some embodiments, the fifth period is between 2 and 10 hours.

[0040] In some embodiments, the second impurity includes one or more of calcium fluoride, magnesium fluoride, and lead fluoride.

[0041] In some embodiments, the sixth period is between 0.5 and 2 hours.

[0042] In some embodiments, the seventh hour period is between 0.5 and 2 hours.

[0043] An embodiment of the present invention provides a method for treating a leachate of a waste positive electrode material of a lithium battery, the leachate of the waste positive electrode material of the lithium battery containing at least calcium ions, magnesium ions or lead ions. Before removing the calcium ions, magnesium ions or lead ions, the method includes: Slot Add an appropriate amount of the second bottom liquid into the second reaction vessel. Slot maintaining the reaction temperature within the reaction vessel at a second temperature above room temperature, and then Slot introducing a protective gas into the second reaction vessel; and feeding the first filtrate, the complexing agent and the second alkaline solution at an appropriate flow rate to the second reaction vessel. Slot After inhaling the mixture into the container and reacting for a third hour, Slotand overflowing the second alkaline solution from the second alkaline solution. During the third time, the reaction is stably maintained at the second temperature and the flow rate of the second alkaline solution is adjusted to stably carry out the reaction in the first pH range. Thereafter, a second separation step is carried out to obtain a target substance precipitate and a second filtrate. The second filtrate contains lithium ions.

[0044] Before removing impurities from the lithium battery waste positive electrode material, the solid-phase lithium battery waste positive electrode material needs to be dissolved to obtain a leachate of the lithium battery waste positive electrode material. Specifically, a leachant is added to the lithium battery waste positive electrode material to dissolve it until the pH is in the second range, and then a fourth separation step is performed to obtain a third impurity and a leachate of the lithium battery waste positive electrode material. In some embodiments, the lithium battery waste positive electrode material may include a lithium nickel cobalt manganese oxide battery material. In some embodiments, the lithium battery waste positive electrode material may include one or more of a lithium cobalt oxide battery material, a lithium cobalt manganese oxide battery material, a lithium cobalt alumina battery material, and a lithium manganese oxide battery material. In some embodiments, the leachant may include at least a reducing agent, a first acid, and water. In some embodiments, the reducing agent may include a hydrogen peroxide solution. In some embodiments, the reducing agent may further include sulfur dioxide gas, hydrazine hydrate (N2H4·H2O), and the like. In some examples, the first acid may include sulfuric acid, hydrochloric acid, nitric acid, permanganic acid, sulfurous acid, hypochlorous acid, and the like.

[0045] In some embodiments, the leaching agent may be used to dissolve the waste positive electrode material of the lithium battery under certain conditions. In some embodiments, the certain conditions may include an initial dissolution temperature, a dissolution pressure, and a dissolution pH. In some embodiments, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 0°C to 80°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 20°C to 76°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 30°C to 73°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 40°C to 70°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 45°C to 67°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 50°C to 65°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 55°C to 63°C. Preferably, the initial dissolution temperature of the waste positive electrode material of the lithium battery may be 57°C to 60°C. In some embodiments, the dissolution pressure of the waste positive electrode material of the lithium battery may be normal pressure, i.e., 101.325 KPa. In some embodiments, the dissolution pressure of the waste positive electrode material of the lithium battery may be other pressure values, but the present invention is not limited thereto. In some embodiments, the pH for dissolving the waste positive electrode material of the lithium battery may be in a second range. Since the waste positive electrode material of the lithium battery contains various metal elements, the dissolution pH of the waste positive electrode material of the lithium battery is more acidic in order to dissolve the waste positive electrode material of the lithium battery sufficiently. For example, the second range may be pH=0-2.5. Preferably, the second range may be pH=0.2-2.3. Preferably, the second range may be pH=0.4-2.2. Preferably, the second range may be pH=0.5-2.0. Preferably, the second range may be pH=0.6-1.8. Preferably, the second range may be pH=0.7-1.6. Preferably, the second range may be pH=0.8 to 1.4. Preferably, the second range may be pH=0.9 to 1.2. More preferably, the dissolution pH may be pH=1.0. In some embodiments, the certain conditions may further include a particle size of the waste positive electrode material of the lithium battery.For example, before dissolving the waste positive electrode material of the lithium battery, the waste positive electrode material of the lithium battery is subjected to a pulverization process, and dissolution is performed after the waste positive electrode material of the lithium battery becomes smaller than a certain particle size. In some embodiments, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.01 to 2 mm. Preferably, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.02 to 1.5 mm. Preferably, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.04 to 1.2 mm. Preferably, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.05 to 0.8 mm. Preferably, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.06 to 0.4 mm. Preferably, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.08 to 0.2 mm. Preferably, the particle size of the waste positive electrode material of the lithium battery after pulverization may include 0.1 mm. In the process of dissolving the waste positive electrode material of lithium batteries, the contact area between the pulverized waste positive electrode material of lithium batteries and the leaching agent is large, so the dissolution rate of the waste positive electrode material of lithium batteries is fast.

[0046] The leachate of the waste positive electrode material of the lithium battery obtained may be treated by further removing impurities. The step of further removing impurities from the leachate of the waste positive electrode material of the lithium battery and treating the same includes a step (1) of precipitating the leachate of the waste positive electrode material of the lithium battery to remove iron ions, aluminum ions and at least a part of copper ions to obtain a first filtrate, a step (2) of precipitating the first filtrate to remove lithium ions to obtain a second filtrate containing lithium ions and a target substance precipitate, and a step (3) of dissolving the target substance precipitate to obtain a first solution, and precipitating the first solution to remove calcium ions, magnesium ions and at least a part of lead ions to obtain a target solution. Furthermore, a third alkaline solution may be added to the target solution to obtain a precursor precipitate of the positive electrode material of the lithium battery.

[0047] The above three impurity removal and treatment processes are all continuously reacted under stable reaction conditions (for example, a constant reaction temperature within the measurement error tolerance (measurement error tolerance of reaction temperature is ±2.5°C)), a constant pH value (measurement error tolerance of pH is ±0.05), a constant pH range (measurement error tolerance of pH range is ±0.05) or a constant fluoride ion concentration range (measurement error tolerance of fluoride ion concentration range is ±0.0005mol / L). Slot Two or more reactants are simultaneously sucked into the reaction chamber. The speed of the sucked-in material is determined by the reaction rate. Slot The volume of the reaction is small, and in addition to the control of the pH meter, fluorine ion meter and constant temperature equipment, the reaction is considered to be carried out under relatively stable conditions, which is different from the usual chemical reaction process in which the pH value gradually changes with the addition of the precipitant until it reaches the pH value at which the reaction is completed. Slot react continuously in the Slot The reaction mixture is continuously overflowing from the reaction mixture, and the subsequent reaction is filled with the reaction mixture (overflow reaction). Slot The above three reaction steps are all carried out under stable reaction conditions, so that a precipitate with high crystallinity and large particle size can be obtained, and filtration and washing can be easily performed. The above impurity removal and treatment step further includes a lithium ion removal step, which achieves the purpose of removing lithium ions and recovering lithium before preparing the lithium battery positive electrode material precursor precipitate, while minimizing the impact on the control of reaction parameters in the subsequent impurity removal step, and allowing the subsequent reactions to be carried out under relatively stable conditions. [Brief description of the drawings]

[0048] The present invention will now be described in detail with reference to examples.

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 8

[0049] In order to more clearly describe the technical solutions of the embodiments of the present invention, the drawings necessary for the description of the embodiments will be briefly described below. Obviously, the drawings described below are only examples or embodiments of the present invention, and those skilled in the art can apply the present application to other similar scenarios based on these drawings without creative efforts. Unless otherwise clear or specified from the language environment, the same symbols in the drawings represent the same structures or operations.

[0050] It should be understood that the terms "system", "apparatus", "unit" and / or "module" used herein are ways to distinguish between various assemblies, elements, parts, portions or assemblies at different levels. As used herein, the terms "impurity removal method", "treatment method", "impurity removal and treatment method", "lithium ion recovery method" or "impurity removal and treatment method in a lithium battery waste positive electrode material recovery process" refer to one or more steps or processes in a lithium battery waste positive electrode material recovery process. However, other terms can be used instead of the above terms if the other terms can achieve the same purpose.

[0051] As used herein and in the claims, unless the context clearly dictates otherwise, terms such as "a," "one," "one kind," and / or "the" do not specifically refer to the singular but may include the plural. In general, the terms "comprise" and "contain" are presented to include only the specifically identified steps and elements, and these steps and elements are not an exclusive list, and the method or apparatus may also include other steps or elements. Numeric ranges used in the present invention simply represent each numerical value included in the range.

[0052] Hereinafter, the process of removing impurities from the leachate of discarded positive electrode material of lithium batteries will be described in detail with reference to FIGS.

[0053] FIG. 1 is a flow chart illustrating an example of a method 100 for removing impurities in a recycling process of waste positive electrode materials of lithium batteries, according to some embodiments of the present invention.

[0054] The impurity removal process in the recovery process of waste positive electrode materials from lithium batteries is a reaction Slot or aging Slot 8 is a diagram showing an impurity removal and treatment method according to some embodiments of the present invention. As shown in FIG. 8, the leaching solution of the waste positive electrode material of the lithium battery and the first alkaline solution are reacted by the feed pump A and the feed pump B, respectively. SlotInhalation into the body and reaction after a certain period of time Slot Aging by exhaust pipe A Slot The reaction mixture is then allowed to overflow and aged. Slot is the first reaction Slot and aging Slot The first aging Slot may be also possible.

[0055] Step 110: First reaction Slot Add an appropriate amount of the first bottom liquid into the first reaction vessel. Slot The reaction temperature within the reactor is maintained at a first temperature above room temperature.

[0056] First reaction Slot The volume of the first reaction may be set by the manufacturing process requirements or the supply of reactants. Slot The volume of the first bottom liquid may be 50 L, 80 L or 100 L. The first bottom liquid is added to the first reaction tank before the reaction material is sucked in. Slot The first bottom liquid is a liquid placed in the container, and a pH meter is immersed so that the electrodes of the pH meter are positioned below the liquid level. In some embodiments, the first bottom liquid may be deionized water or a solution having a first pH value. For example, the solution having the first pH value may be a nickel-cobalt-manganese solution. Also, for example, the solution having the first pH value may be an acid solution (e.g., a sulfuric acid solution). For details regarding the pH being the first pH value, the description of step 120 can be referred to, and therefore a detailed description will be omitted here.

[0057] The first temperature may be higher than room temperature. In some embodiments, the first temperature may be any value between 50 and 90°C. Preferably, the first temperature may be any value between 52 and 88°C. Preferably, the first temperature may be any value between 55 and 86°C. Preferably, the first temperature may be any value between 58 and 83°C. Preferably, the first temperature may be any value between 60 and 80°C. Preferably, the first temperature may be any value between 62 and 78°C. Preferably, the first temperature may be any value between 65 and 76°C. Preferably, the first temperature may be any value between 67 and 73°C. Preferably, the first temperature may be any value between 69 and 71°C. Preferably, the first temperature may be 50°C. Preferably, the first temperature may be 55°C. Preferably, the first temperature may be 60°C. Preferably, the first temperature may be 65°C. Preferably, the first temperature may be 70°C. Preferably, the first temperature may be 75° C. Preferably, the first temperature may be 80° C. Preferably, the first temperature may be 85° C. More preferably, the first temperature may be 90° C. In some embodiments, the first reaction Slot Heat the first reaction Slot The reaction temperature in the first reaction chamber may be maintained at the first temperature. Slot The heating method may be electric heating, steam heating, heat transfer oil circulation heating or far infrared heating, but the present invention is not limited thereto.

[0058] Since the first temperature is higher than room temperature, crystallization occurs easily and large crystal grains are obtained.

[0059] Step 120: The leaching solution of the waste positive electrode material of the lithium battery and the first alkaline solution are respectively subjected to a first reaction at appropriate flow rates. Slot After inhaling and reacting for 1 hour, the first reaction Slot During the first time period, the reaction is maintained at a stable first temperature, and the flow rate of the first alkaline solution is adjusted to maintain the reaction at a stable first pH value.

[0060] The leachate of the waste positive electrode material of the lithium battery can be obtained by dissolving the waste positive electrode material of the lithium battery. For details on obtaining the leachate of the waste positive electrode material of the lithium battery, the above contents can be referred to, and the detailed description thereof will be omitted here. In some embodiments, the leachate of the waste positive electrode material of the lithium battery can be a solution containing lithium ions, nickel ions, cobalt ions, manganese ions, etc. The flow rates of the leachate of the waste positive electrode material of the lithium battery and the first alkaline solution can be set according to the manufacturing process requirements, and the appropriate flow rates are set to react the leachate of the waste positive electrode material of the lithium battery with the first alkaline solution for a first time, and then the first reaction is performed. Slot For example, depending on the scale of production, the first reaction Slot The volume of the first alkaline solution may be 50 L, the flow rate of the leachate of the waste positive electrode material of the lithium battery may be 50 to 250 mL / min, and the flow rate of the first alkaline solution may be controlled so as to stably carry out the reaction at a first pH value. Slot When the lithium battery waste positive electrode material leachate is inhaled into the feed pipe, the first reaction Slot The first reaction Slot When the first alkaline solution is sucked into the first reaction vessel, the feed pipe of the first alkaline solution is connected to the first reaction vessel. Slot As shown in FIG. 8, the leaching solution of the waste positive electrode material of the lithium battery and the first alkaline solution are reacted by the feed pump A and the feed pump B, respectively. Slot (i.e., the first reaction Slot The feed pump A and the feed pump B are Slot In some embodiments, the first reaction Slot is the first reaction Slot The apparatus may include a stirring module for stirring the leaching solution of the waste positive electrode material of the lithium batteries and the first alkaline solution therein.

[0061] In some embodiments, the first alkali may include lithium hydroxide. The lithium hydroxide may have a concentration of 1 to 4 mol / L. Preferably, the lithium hydroxide may have a concentration of 2 mol / L. Preferably, the lithium hydroxide may have a concentration of 3 mol / L. In some embodiments, the first pH value is any value of pH=5.5 to 6.7. Preferably, the first pH value is any value of pH=5.7 to 6.5. Preferably, the first pH value is any value of pH=5.9 to 6.3. Preferably, the first pH value is any value of pH=6.0 to 6.2. Preferably, the first pH value may be pH=5.5. Preferably, the first pH value may be pH=5.8. Preferably, the first pH value may be pH=6.0. Preferably, the first pH value may be pH=6.3. Preferably, the first pH value may be pH=6.5. Preferably, the first pH value may be pH=6.7. In some embodiments, stabilizing the pH of the solution at the first pH value may mean that the pH of the solution is always equal to the first pH value, or may be less than a preset value (e.g., 0.05, 0.10, or 0.15) away from the first pH value. For example, if the preset value is 0.10 and the first pH value is 6.3, then the pH of the solution may be 6.2, 6.25, 6.3, 6.35, 6.4, or may fluctuate within the range of 6.2 to 6.4, all of which may be considered to stabilize the pH of the solution at the first pH value. SlotWhen the first alkaline solution is inhaled within the inhalation time, the pH value of the solution is measured in real time by a pH meter and the inhalation rate of the first alkaline solution is controlled to stabilize the pH of the solution at the first pH value or the measurement error range (for example, if the measurement error tolerance range of pH is ±0.05, the first pH value may be any value between pH=5.45 and 6.75), or the difference from the first pH value is kept within a preset range. For example, if the first pH value is required to be pH=6.3, if the flow rate of the first alkaline solution is 20 ml / min, the pH of the solution is lowered and, at that time, the flow rate of the first alkaline solution needs to be appropriately increased to raise the pH of the solution to 6.3, while, if the flow rate of the first alkaline solution is 30 ml / min, the pH of the solution is raised and the flow rate of the first alkaline solution needs to be appropriately decreased to lower the pH of the solution to 6.3. Note that controlling the intake rate of the first alkaline solution by measuring the pH value of the solution in real time with a pH meter may be controlled by automatically linking the pH meter with a feed pump for the first alkaline solution.

[0062] In some embodiments, the first time period may be 2 to 10 h. Preferably, the first time period may be 2.5 to 8.0 h. Preferably, the first time period may be 3.0 to 7.0 h. Preferably, the first time period may be 3.5 to 7.5 h. Preferably, the first time period may be 4.0 to 7.0 h. Preferably, the first time period may be 4.5 to 6.5 h. Preferably, the first time period may be 5.0 to 6.0 h. Preferably, the first time period may be 5.3 to 5.7 h. Preferably, the first time period may be 3 h. Preferably, the first time period may be 4 h. Preferably, the first time period may be 5 h. Preferably, the first time period may be 6 h. Preferably, the first time period may be 7 h. More preferably, the first time period may be 8 h. First Reaction Slot The volume and location of the spill port (e.g., the spill port is located in the first reaction Slot The reaction materials are then fed to the first reaction Slot After allowing the mixture to react for 2 to 10 hours, the first reaction Slot From the first agingSlot Let it overflow.

[0063] By maintaining the reaction temperature at the first temperature and stabilizing the pH of the solution at the first pH value, the reaction conditions in the reaction step can be stabilized, and the crystal grains and crystal shapes of the precipitates produced can be made uniform. Slot The crystals obtained by this precipitation are large in size, and the precipitate can be easily filtered and washed in the following steps. Slot By continuously drawing in reactive materials into the reactor and causing them to react continuously, it is possible to continuously process waste positive electrode materials from lithium batteries into a leachate, making it easy to remove impurities on an industrial scale.

[0064] Step 130: First reaction Slot The overflow mixture is aged and the aging temperature is maintained at the first temperature and aged for a second period of time.

[0065] This aging process is called the first aging process. Slot In some embodiments, the first aging may be performed within Slot Heat the first aging Slot The aging temperature in the first aging chamber may be maintained at the first temperature. Slot The heating method may include electric heating, steam heating, heat transfer oil circulation heating, or far infrared heating, but is not limited thereto in the present invention. For details regarding the first temperature, the description of step 110 can be referred to, and detailed description here will be omitted. In some embodiments, the second time may be 0.5 to 2 h. Preferably, the second time may be 0.8 to 1.8 h. Preferably, the second time may be 1.0 to 1.6 h. Preferably, the second time may be 1.2 to 1.4 h. Preferably, the second time may be 0.5 h. Preferably, the second time may be 1 h. Preferably, the second time may be 1.5 h. More preferably, the second time may be 2 h.

[0066] Aging the fully reacted mixture for a second period of time promotes grain growth of the precipitate crystals in the reacted mixture and results in a more uniform grain size distribution.

[0067] Step 140: Thereafter, a first separation step is performed to obtain a first impurity and a first filtrate.

[0068] Before carrying out the first separation step, the aged mixture may be cooled to room temperature. This cooling step may be carried out in a first buffer tank, and the aged mixture may be sucked into the first buffer tank and cooled. The cooling method for the aged mixture may be natural cooling, air cooling, or liquid cooling (e.g., cooling with a liquid cooling medium such as water, alcohol, ethylene glycol, isobutyl alcohol, hexane, etc.).

[0069] In some embodiments, the cooled mixture may be subjected to a first separation step to obtain a first impurity and a first filtrate. Specifically, the first separation step may be a solid-liquid separation step. For example, the first separation method may include filtration, gravity settling, centrifugal settling, pressure filtration, etc. Since waste positive electrode materials of different lithium batteries contain different impurity metal elements, the conditions of the impurity removal reaction may be different, and the obtained first impurity and / or first filtrate may be different. In some embodiments, the first impurity may include at least iron hydroxide. In some embodiments, the first impurity may further include iron hydroxide and aluminum hydroxide. In some embodiments, the first impurity may further include copper hydroxide. In some embodiments, the first filtrate may include at least lithium ions and cobalt ions. For example, when the lithium battery positive electrode material, which is a product produced from the waste positive electrode material of the lithium battery (for example, a lithium nickel cobalt manganese oxide battery material), does not contain aluminum element, the leachate of the waste positive electrode material of the lithium battery may contain lithium ions, nickel ions, aluminum ions, iron ions, manganese ions, cobalt ions, etc., and the first pH value may be pH=5.5 to remove impurity metal element ions such as aluminum ions and iron ions. In this case, the first impurities may include aluminum hydroxide, iron hydroxide, etc., and the first filtrate may include lithium ions, nickel ions, manganese ions, cobalt ions, etc.

[0070] In the above method, a first reaction of a leachate of a waste positive electrode material of a lithium battery and a first alkaline solution is performed. Slot By controlling the inlet flow rate, pH value, reaction temperature, reaction time and aging time, the crystal grains can be grown to large crystal grains. In addition, by reacting at a certain pH value, it is possible to obtain coprecipitates of metals such as iron, aluminum, copper and nickel, which makes it easier to carry out the first separation step, reduces the amount of water used for washing in the first separation step and the washing time, and also reduces the consumption of nickel-cobalt-manganese ions in the washing step, thereby improving the recovery rate of nickel-cobalt-manganese.

[0071] Hereinafter, the method for removing iron ions and aluminum ions in the process for recovering waste positive electrode material from lithium batteries will be described in detail with reference to Examples 1 and 2. The reaction conditions, reaction materials, and amounts of reaction materials used in Examples 1 and 2 are merely for explaining the method for removing iron ions and aluminum ions in the process for recovering waste positive electrode material from lithium batteries, and do not limit the scope of protection of the present invention. Example 1 is an example of a method for mass-producing the removal of impurities from the leachate of waste positive electrode material from lithium batteries, and FIG. 2 is an example using the method for removing impurities in FIG. 1. Example 1 is a control group for Example 2. Example 1

[0072] Step 1: 50 L first reaction at room temperature Slot 30L of leachate from discarded positive electrode material of lithium batteries was added to the tank.

[0073] Step 2: The first reaction is performed by controlling the peristaltic pump online with a pH meter. Slot A 2 mol / L lithium hydroxide solution was inhaled into the bloodstream, and when the pH value stabilized at 5.5, the inhalation of the lithium hydroxide solution was stopped and the mixture was allowed to react for 1 hour. A total of 4.2 L of lithium hydroxide solution was consumed during the reaction.

[0074] Step 3: The reacted mixture was filtered through a filter press with 200 mesh filter cloth, and the cake was purged with 0.6 MPa high-pressure air until the filtrate stopped flowing out. In the filtration process, if the internal pressure of the filter press rises quickly, for example, the pressure rises to the upper limit of 0.5 MPa within 2 minutes, filtration needs to be stopped, which indicates the poor filterability of this precipitate. After the pressure drops to 0 MPa, the filtration operation is resumed.

[0075] Step 4: Observe the filtered filtrate, if you find that the filtrate becomes cloudy, it indicates that the precipitate is not completely filtered.

[0076] Step 5: The filtered cake was collected to obtain 267g of wet cake, and after drying, 92.4g of dry cake was obtained.

[0077] Step 6: The leachate, dried cake, and filtrate of the discarded positive electrode material of lithium batteries were subjected to ICP measurement, and the dried cake was subjected to SEM measurement. Example 2

[0078] Step 1: 50 L of the first reaction Slot 10 L of the filtrate from Example 1 was added as the first bottom liquid to the bottom of the flask, so that the electrode of the pH meter was positioned below the liquid level. Slot The reaction temperature was kept constant at 70° C. by applying heat.

[0079] Step 2: The leaching solution of the waste positive electrode material of lithium batteries and 2mol / L lithium hydroxide solution were pumped through the first reaction by a peristaltic pump, respectively. Slot The suction rate of the leaching solution of the waste positive electrode material of the lithium battery was controlled at 200ml / min, and the suction rate of the lithium hydroxide solution was controlled by an online pH meter to adjust the pH of the mixture to 5.5. After reacting for 3 hours, the first reaction Slot The mixture is poured out from the overflow port of the first aging Slot In this process, 36 L of leachate from lithium battery waste positive electrode material and 5.04 L of lithium hydroxide solution were sucked in and reacted.

[0080] Step 3: First aging Slot The mixture was heated to maintain the aging temperature constant at 70°C, and the mixture was subjected to the first aging process. Slot It was aged for 1 hour inside the

[0081] Step 4: The aged mixture was cooled to room temperature in the first buffer tank and then filtered through a filter press, and the cake was washed with 0.6 MPa high-pressure air until the filtrate stopped flowing out. In the filtration process, the pressure of the filter press was always kept lower than 0.2 MPa, which indicates that the filterability of this precipitate is excellent.

[0082] Step 5: Observe the filtered filtrate, if the filtrate is found to be clear, it indicates that the precipitate has been completely filtered. The obtained filtrate was 51.04L.

[0083] Step 6: The filtered cake was collected to obtain 194.4g of wet cake, and after drying, 112g of dry cake was obtained.

[0084] Step 7: The filtrate and the dried cake were subjected to ICP measurement, and the dried cake was subjected to SEM measurement.

[0085] The moisture content of the cakes of Example 1 and Example 2 is calculated.

[0086] Moisture content of the cake in Example 1 W1 = (267g - 92.4g) / 267g = 65.4%

[0087] Moisture content of the cake in Example 2 W2 = (194.4g - 112g) / 194.4g = 42.4%

[0088] According to the calculation results of the moisture content of Example 1 and Example 2, the following was found. The moisture content of the cake of Example 2 was lower than that of Example 1, which indicates that the solid-liquid separation in the filtration process of Example 2 was more complete. Comparing Figures 4A and 4B, the crystal grains of the precipitate in Example 2 were larger than those in Example 1, and at a constant pH of 5.5, some nickel ions co-precipitated with aluminum ions and iron ions, improving the structure of the aluminum hydroxide precipitate and preventing it from becoming colloidal, making it easier to filter.

[0089] From the ICP measurement results of Example 1 and Example 2, the data in Table 1 can be obtained. ICP analysis results JPEG0007606612000001.jpg51170

[0090] According to Table 1, the metal ion removal rates of Example 1 and Example 2 can be further calculated. The removal rates M of aluminum ions, iron ions, and copper ions in Example 1 were calculated as follows: M content in leaching solution x total volume of leaching solution containing reaction participants - M content in filtrate x total volume of filtrate) / (M content in leaching solution x total volume of leaching solution containing reaction participants) x 100%. The removal rate of aluminum ions: Al removal rate = (156 x 30L - 10.8 x 34.2L) / (156 x 30L) x 100% = 92.1%, the removal rate of iron ions: Fe removal rate = (52.6 x 30L - 0.88 x 34.2L) / (52.6 x 30L) x 100% = 98.1%, and the removal rate of copper ions: Cu removal rate = (12.5 x 30L - 8.12 x 34.2L) / (12.5 x 30L) x 100% = 26%.

[0091] The loss rates of nickel ions, cobalt ions, and manganese ions in Example 1 were calculated as follows: M=(weight of dried cake×content of M in dried cake) / (content of M in leaching solution×total volume of leaching solution containing reaction participants)×100%. The loss rate of nickel ions: Ni loss rate=(92.4g×0.42) / (53700×30L / 1000)×100%=2.4%, the loss rate of cobalt ions: Co loss rate=(92.4g×0.074) / (10700×30L / 1000)×100%=2.13%, and the loss rate of cobalt ions: Mn loss rate=(92.4g×0.006) / (8620×30L / 1000)×100%=0.21%.

[0092] In Example 2, the removal rates of aluminum ions, iron ions, and copper ions M=(M content in leaching solution×total volume of leaching solution containing reaction participants-M content in filtrate×total volume of filtrate) / (M content in leaching solution×total volume of leaching solution containing reaction participants)×100%. The removal rate of aluminum ions: Al removal rate=(156×36L-0) / (156×36L)=100%, the removal rate of iron ions: Fe removal rate=(52.6×36L-0.5×51.04L) / (52.6×36L)=98.65%, and the removal rate of copper ions: Cu removal rate=(12.5×36L-6.2×51.04L) / (12.5×36L)=29.7% were calculated.

[0093] The loss rates of nickel ions, cobalt ions, and manganese ions in Example 2 were calculated as follows: M=(weight of dried cake×content of M in dried cake) / (content of M in leaching solution×total volume of eluate containing reaction participants)×100%. The loss rate of nickel ions: Ni loss rate=(112g×0.31) / (53700×36L / 1000g / L)×100%=1.8%, the loss rate of cobalt ions: Co loss rate=(112g×0.028) / (10700×36L / 1000g / L)×100%=0.8%, and the loss rate of manganese ions: Mn loss rate=(112g×0.0042) / (8620×36L / 1000g / L)×100%=0.15%.

[0094] According to the calculation results of the removal rates of aluminum ions, iron ions, and copper ions in Examples 1 and 2, it was found that the removal rates of aluminum ions, iron ions, and copper ions in Example 2 were higher than those in Example 1, and the effect of removing aluminum ions, iron ions, and copper ions from the leachate of the waste positive electrode material of the lithium battery in Example 2 was better. Furthermore, while the slag in Example 1 could hardly be washed, the slag in Example 2 was enriched to a certain extent in the filter press and could be washed at once with a small amount of washing water, recovering some of the aluminum ions, iron ions, and copper ions, and further reducing the loss rate of aluminum ions, iron ions, and copper ions.

[0095] Fig. 4A is an SEM image of the slag of Example 1 of the present invention, and Fig. 4B is an SEM image of the slag of Example 2 of the present invention. Fig. 4A and Fig. 4B show that the crystal grains of the slag of Example 1 are small, formed in a block shape, have a dense texture, and have high compactability, while the crystal grains of the slag of Example 2 are large, formed in a block shape after drying, but have a coarse texture and low compactability. According to the method of Example 2, the precipitate obtained by removing impurities from the leachate of the waste positive electrode material of the lithium battery has larger crystal grains and a lower water content.

[0096] The comparison results between Example 1 and Example 2 are as follows. In Example 1, at room temperature, the solution pH was 5.5, the reaction material was added at once and reacted for 1 hour, and the impurity removal treatment was performed on the leachate of the waste positive electrode material of the lithium battery. On the other hand, in Example 2, the reaction temperature was maintained at 70°C, the pH of the solution was maintained at 5.5, the material was continuously supplied, the reaction material was reacted sufficiently for 3 hours, and the leachate was aged for 1 hour, and the impurity removal treatment was performed on the leachate of the waste positive electrode material of the lithium battery. According to the above comparison results, in Example 2, the solution pH value was kept the same as in Example 1, the reaction temperature was kept constant at a relatively high level, and the reaction rate of the reaction material was controlled to react sufficiently for 3 hours and aged for 1 hour, and the crystal grains of the precipitate generated were large, and the precipitate was easily filtered and washed, which increased the removal rate of Al, Fe, and Mn metals and improved the impurity removal effect.

[0097] In the recovery process of waste positive electrode materials of lithium batteries, the pH of the solution is monitored by a pH meter to control the reaction process in real time, so the pH meter is required to have high sensitivity and it is necessary to avoid the occurrence of poisoning of the electrode of the pH meter. The inventor of the present application has discovered the following. When the lithium ions in the solution in the recovery process of waste positive electrode materials of lithium batteries have a pH>7, they are likely to poison the electrode of the pH meter, making it difficult to monitor the actual pH value of the solution and difficult to control other parameters in the reaction process (e.g., the flow rate of the first alkaline solution), which is disadvantageous in controlling the reaction conditions during the preparation of the ternary precursor (also called precursor precipitation) by coprecipitation. In addition, when the calcium ions, magnesium ions, or lead ions are subsequently removed, precipitation is performed using a fluorine-containing precipitant (e.g., sodium fluoride) (for details, see the explanation of FIG. 3), but lithium fluoride has low solubility and is removed as an impurity together with the calcium ions, magnesium ions, or lead ions, which reduces the recovery rate of lithium ions in the recovery process of waste positive electrode materials of lithium batteries. Therefore, in the technical solution of the present invention, it is necessary to recover lithium ions in the impurity removal process before carrying out the subsequent impurity removal process.

[0098] FIG. 2 is a flow chart illustrating an example of a lithium recovery method 200 in a recovery process of waste positive electrode materials of lithium batteries according to some other embodiments of the present invention.

[0099] The lithium ion recovery process in the recovery process of waste positive electrode materials from lithium batteries is a reaction Slot or aging Slot As shown in FIG. 8, the first filtrate, the complexing agent, and the second alkaline solution are respectively fed to a feed pump A, a feed pump B, and a feed pump C (not shown) to react with each other. Slot Inhalation into the body and reaction after a certain period of time Slot Aging by exhaust pipe A Slot The reaction mixture is then allowed to overflow and aged. Slot is the second reaction Slot and aging Slot The second aging Slot may be also possible.

[0100] Step 210: Second Reaction Slot Add an appropriate amount of the second bottom liquid into the second reaction vessel. Slot maintaining the reaction temperature in the reaction vessel at a second temperature higher than room temperature, and then Slot A protective gas is introduced into the chamber.

[0101] Second reaction Slot The volume of the second reaction may be set by the manufacturing process requirements or the supply of reactants. Slot The volume of the second bottom liquid may be 50 L, 80 L or 100 L. The second bottom liquid is added to the second reaction vessel before the reaction material is sucked in. Slot The second bottom liquid is a liquid that is placed in the bottom of the container, and the pH meter is immersed in the liquid so that the electrodes of the pH meter are below the liquid level. In some embodiments, the second bottom liquid may be aqueous ammonia.

[0102] The second temperature may be higher than room temperature. In some embodiments, the second temperature may be any value between 40 and 70°C. Preferably, the second temperature may be any value between 43 and 68°C. Preferably, the second temperature may be any value between 46 and 66°C. Preferably, the second temperature may be any value between 48 and 64°C. Preferably, the second temperature may be any value between 50 and 62°C. Preferably, the second temperature may be any value between 52 and 60°C. Preferably, the second temperature may be any value between 54 and 58°C. Preferably, the second temperature may be 40°C. Preferably, the second temperature may be 45°C. Preferably, the second temperature may be 50°C. Preferably, the second temperature may be 55°C. Preferably, the second temperature may be 60°C. Preferably, the second temperature may be 65°C. More preferably, the second temperature may be 70°C. In some embodiments, the second reaction Slot Heat the second reaction Slot The reaction temperature within the second reaction chamber may be maintained at a second temperature. Slot The heating method may include, but is not limited to, electric heating, steam heating, heat transfer oil circulation heating, or far infrared heating in the present invention. Since the second temperature is higher than the crystallization temperature of the prior art, crystals that are easy to crystallize and have large crystal grains are obtained.

[0103] In some embodiments, the protective gas may include nitrogen gas or an inert gas (eg, helium, neon gas, or argon gas).

[0104] Step 220: The first filtrate, the complexing agent, and the second alkaline solution are each subjected to a suitable flow rate to carry out a second reaction. Slot After inhaling the substance into the stomach and allowing it to react for 3 hours, the second reaction Slot During the third time period, the reaction is maintained at a stable second temperature, and the flow rate of the second alkaline solution is adjusted to stably carry out the reaction within a first pH range.

[0105] The flow rates of the first filtrate, the complexing agent and the second alkaline solution may be set according to the manufacturing process requirements, and the first filtrate, the complexing agent and the second alkaline solution are reacted for a third time by setting an appropriate flow rate, and then the second reaction is performed. Slot For example, the second reaction Slot The volume of the second alkaline solution is 50 L, the flow rate of the first filtrate is 40-300 mL / min, the flow rate of the complexing agent is set in proportion to the flow rate of the first filtrate (for example, the flow rate of the complexing agent may be 1-50 mL / min), and the flow rate of the second alkaline solution is controlled to stably carry out the reaction within the first pH range or within the measurement error range. In some embodiments, the complexing agent may include ammonia water, oxalic acid, ethylenediaminetetraacetic acid (EDTA), or citric acid. The complexing agent forms a complex with nickel ions, cobalt ions, and manganese ions in the first filtrate, and acts to make the grain size of the crystal grains of the formed precipitate more uniform and facilitate filtration separation.

[0106] In some embodiments, the second alkaline solution is the same as the first alkaline solution. For example, the first alkaline solution is a lithium hydroxide solution and the second alkaline solution is also lithium hydroxide. The first filtrate and the complexing agent are reacted with a second reaction solution. Slot When the first filtrate is introduced into the first reaction vessel, the feed pipe for the first filtrate and the feed pipe for the complexing agent are connected to the first reaction vessel, respectively. Slot In some embodiments, the feed tube for the first filtrate and the feed tube for the complexing agent may be the same or there may be two. Slot The second alkaline solution is introduced into the second reactor through the feed pipe of the second alkaline solution. Slot As shown in FIG. 8, the first filtrate, the complexing agent, and the second alkaline solution are respectively pumped by feed pump A, feed pump B, and feed pump C (not shown). Slot (For example, the second reaction Slot ) and feed tubes A, B and C (not shown) are reactants. Slot In some embodiments, the second reaction Slot is the second reaction SlotThe complexing agent may include a stirring module for stirring the first filtrate, the complexing agent, and the second alkaline solution in the reaction vessel.

[0107] In some embodiments, the first pH range may be pH=10.5-11.8. Preferably, the first pH range may be pH=10.6-11.7. Preferably, the first pH range may be pH=10.7-11.6. Preferably, the first pH range may be pH=10.8-11.5. Preferably, the first pH range may be pH=10.9-11.4. Preferably, the first pH range may be pH=11.0-11.3. More preferably, the first pH range may be pH=11.1-11.2. In some embodiments, stabilizing the pH of the solution in the first pH range may mean that the pH of the solution is always at a value within the first pH range, or may fluctuate within the first pH range. For example, if the first pH range is 10.8 to 11.5, the pH of the solution may be 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, or may vary within the range of 10.8 to 11.5, all of which are considered to stabilize the pH of the solution in the first pH range. Slot When the second alkaline solution is inhaled within a certain time, the pH value of the solution is measured in real time with a pH meter to control the inhalation rate of the second alkaline solution, thereby stabilizing the pH of the solution within the first pH range or the measurement error range (the measurement error tolerance of the pH range is ±0.05, i.e., the first pH range may be pH=10.45-11.85). For example, the first pH range must be pH=10.7-11.6, and if the flow rate of the second alkaline solution is 80 ml / min and the pH of the solution is lowered below 10.7, the flow rate of the second alkaline solution must be appropriately increased to raise the pH of the solution within the range of pH=10.7-11.6, while if the flow rate of the second alkaline solution is 200 ml / min and the pH of the solution exceeds 11.6, the flow rate of the second alkaline solution must be appropriately decreased to lower the pH of the solution within the range of pH=10.7-11.6.

[0108] In some embodiments, the third time may be 2 to 10 h. Preferably, the third time may be 2.5 to 9 h. Preferably, the third time may be 3 to 8 h. Preferably, the third time may be 4.0 to 7.0 h. Preferably, the third time may be 4.5 to 6.5 h. Preferably, the third time may be 5.0 to 6.0 h. Preferably, the third time may be 5.3 to 5.7 h. Preferably, the third time may be 3 h. Preferably, the third time may be 4 h. Preferably, the third time may be 5 h. Preferably, the third time may be 6 h. Preferably, the third time may be 7 h. More preferably, the third time may be 8 h. Second Reaction Slot The volume and location of the spillway (e.g., the spillway is located in the second reaction Slot The reaction material is then transferred to the second reaction Slot After the reaction is complete for 3 to 8 hours, the second reaction Slot From the second aging Slot Let it overflow.

[0109] Second reaction Slot The first filtrate, the complexing agent and the second alkaline solution are continuously drawn into the reactor and reacted continuously, and the mixture is then subjected to the second reaction. Slot The first filtrate is allowed to stagnate for 2 to 10 hours in the reaction tank to allow sufficient reaction and precipitation, thereby enabling continuous treatment of the first filtrate.

[0110] Step 230: Second Reaction Slot The overflow mixture is aged and the aging temperature is maintained at the second temperature and aged for a fourth hour.

[0111] This aging process is called the second aging process. Slot In some embodiments, the second aging may be performed within Slot Heat the second aging Slot The aging temperature in the second aging step may be maintained at the second temperature. SlotThe heating method may include electric heating, steam heating, heat transfer oil circulation heating, or far infrared heating, but is not limited thereto in the present invention. For details regarding the second temperature, the description of step 210 can be referred to, and detailed description here will be omitted. In some embodiments, the fourth time may be 0.5 to 2 h. Preferably, the fourth time may be 0.8 to 1.8 h. Preferably, the fourth time may be 1.0 to 1.6 h. Preferably, the fourth time may be 1.2 to 1.4 h. Preferably, the fourth time may be 0.5 h. Preferably, the fourth time may be 1 h. Preferably, the fourth time may be 1.5 h. More preferably, the fourth time may be 2 h.

[0112] Aging the fully reacted mixture for a fourth hour promotes grain growth of the precipitated crystals in the reacted mixture and results in a more uniform grain size distribution.

[0113] Step 240: Then, a second separation step is performed to obtain a target substance precipitate and a second filtrate, in which lithium ions are contained.

[0114] In some embodiments, the aged mixture may be cooled, and the cooled mixture may be subjected to a second separation step to obtain a target substance precipitate and a second filtrate. Specifically, the second separation step may be a solid-liquid separation step. For example, the second separation method may include filtration, gravity sedimentation, centrifugal sedimentation, pressure filtration, etc. In some embodiments, the target substance precipitate may include one or more precipitates of nickel ions, cobalt ions, and manganese ions. In some embodiments, the second filtrate may include at least lithium ions.

[0115] By the above method, the target substance (one or more of nickel ions, cobalt ions, and manganese ions) is precipitated, and the lithium ions are separated in the form of a solution, thereby achieving the purpose of recovering lithium.

[0116] Hereinafter, the method for recovering lithium ions in the process for recovering waste positive electrode material of a lithium battery will be described in detail with reference to Examples 3 and 4. The reaction conditions, reaction materials, and amounts of reaction materials used in Examples 3 and 4 are merely for explaining the method for recovering lithium ions in the process for recovering waste positive electrode material of a lithium battery, and do not limit the scope of protection of the present invention. Example 3 is an example using the lithium recovery method of FIG. 2. Example 4 is an example of mass-production processing of lithium recovery from the first filtrate. Example 4 is a control group of Example 3. Example 3

[0117] Step 1: 50 L of the second reaction Slot 10 L of deionized water and 300 mL of 23.5% aqueous ammonia were added as a second bottom liquid, the reaction temperature was maintained at 50° C., and nitrogen gas was introduced as a protective gas.

[0118] Step 2: The first filtrate obtained in Example 2 was subjected to a second reaction at a flow rate of 60 mL / min. Slot The second reaction was performed by inhaling 12% ammonia water at a flow rate of 5 mL / min. Slot The flow rate of the 4 mol / L lithium hydroxide solution was controlled in real time by a pH meter, and the pH value of the mixture was adjusted to 10.7-11.2 by controlling the flow rate of the lithium hydroxide solution. After reacting for 5 hours, the mixture was subjected to the second reaction. Slot The second aging process is carried out by overflowing from the overflow port. Slot was allowed to flow into

[0119] Step 3: Second aging Slot The mixture was heated to maintain the aging temperature constant at 50°C, and the mixture was subjected to a second aging process. Slot The mixture was aged at RT for 1 h.

[0120] Step 4: The aged mixture was filtered by a centrifuge and the cake was washed. Note that the amount of water used to wash 100 g of precipitate was 1.12 L.

[0121] Step 5: The filtered cake was collected and the slag was subjected to ICP, XRD and SEM measurements. The lithium content measured by ICP was 0.02%, and the cake was considered clean. Example 4

[0122] Step 1: 50 L second reaction at room temperature Slot 30 L of the first filtrate was added to the flask. The first filtrate was that obtained from Example 2.

[0123] Step 2: The amount of 4 mol / L lithium hydroxide solution to be inhaled was controlled by a pH meter, and the addition was stopped when the pH value reached 10.5. The mixture was allowed to react stably for 1 h.

[0124] Step 3: The reacted mixture was filtered using a centrifuge, and the cake was washed. Note that the amount of water used to wash 100 g of precipitate was 2.32 L.

[0125] Step 4: The filtered cake was collected and the slag was subjected to ICP and XRD measurements. The lithium content measured by ICP was 0.03%, and the cake was considered to be cleaned.

[0126] According to the amount of water used for washing the cake in Example 3 and Example 4, the following was found. When washing 100g of precipitate, the amount of water used in Example 3 is less, which indicates that the crystal grains of the precipitate in Example 3 are larger than those in Example 4. In Example 3, the precipitation crystallization of nickel cobalt manganese is carried out in one constant pH range (for example, 10.7 to 11.2), so that the coprecipitation of nickel cobalt manganese hydroxide can be realized. The pH value at which nickel hydroxide starts to precipitate is 7.2, the pH value at which cobalt hydroxide starts to precipitate is 7.15, the pH value at which manganese hydroxide starts to precipitate is 8.1, and the pH values ​​at which they are completely precipitated are also different, so in Example 4, the nickel cobalt manganese precipitation is precipitated in different pH ranges (lithium hydroxide solution is continuously added until the pH value reaches 10.5), and the coprecipitation of nickel cobalt manganese hydroxide cannot be formed. Therefore, in Example 3, controlling the pH to within the range of 10.7 to 11.2 contributes to the formation of a co-precipitation of nickel-cobalt-manganese hydroxide, and the crystal grains of the precipitate in Example 4 are larger than those in Example 4.

[0127] According to the measurement results of the lithium content of the slag in Example 3 and Example 4, it was found that the lithium content of the cake in Example 3 was lower, and the lithium content of the cake in Example 4 was sufficiently low, but it was deemed possible to wash it. However, the amount of water used to wash 100 g of precipitate in Example 4 was 2.32 L, and the amount of water used to wash 100 g of precipitate in Example 3 was 1.12 L, which is twice the amount of water used in Example 3. Also, the washing time in Example 4 is longer.

[0128] 5 shows the XRD spectrum of the slags of Examples 3 and 4 of the present invention. According to FIG. 5, it can be seen that the slag sample of Example 3 has significant diffraction peaks at 2θ of 20°, 35° and 40°, which are larger than the diffraction peaks at the corresponding positions of Example 4. This indicates that the crystallinity of the nickel cobalt manganese hydroxide of Example 3 after dehydrogenation at 500°C is better than that of Example 4. The crystal grains of the nickel cobalt manganese precipitate obtained after recovering lithium ions by the method of Example 3 are larger, which realizes the coprecipitation of nickel cobalt manganese, and the structure of the precipitate crystal grains is relatively consistent, which contributes to better separation and recovery of lithium ions during filtration.

[0129] Fig. 6 is a SEM image of the slag of the third embodiment of the present invention. The precipitate sample of the fourth embodiment is obviously coagulated after drying, and it is judged that the grains are fine grains and formed into a gel-like substance. The precipitate of the third embodiment is naturally coarse and sandy after drying, and the SEM image shows that its secondary grain structure is good.

[0130] The results of comparing Example 3 and Example 4 are as follows. In Example 3, ammonia water is added as a complexing agent, the reaction temperature is maintained at 50°C, the pH of the solution is maintained at 10.7-11.2, and the reaction is carried out sufficiently for 5 hours, and then aged for 1 hour to recover lithium ions. In Example 4, the solution pH is set to 10.5 at room temperature, and the reaction materials are added at once and reacted for 1 hour to recover lithium ions. In Example 3, a solution pH value similar to that of Example 4 is used, the reaction temperature is relatively high, and ammonia water is added as a complexing agent to form a complex with the target ion, so that dissolution and precipitation are in equilibrium, the feed rate is controlled, the feed time and reaction time are extended, and the aging time is increased, which achieves a synergistic effect, thereby making the crystal grains of the precipitate generated larger, making the crystal grain structure relatively consistent, and making the precipitate easier to filter and wash, thereby improving the recovery rate of lithium ions.

[0131] FIG. 3 is a flow chart illustrating an example of a method 300 for removing impurities in a recycling process of waste positive electrode materials of lithium batteries according to some other embodiments of the present invention.

[0132] The impurity removal process in the recovery process of waste positive electrode materials from lithium batteries is a reaction Slot or aging Slot As shown in FIG. 8, the first solution and the fluorine-containing precipitant are respectively pumped by feed pump A and feed pump B. Slot Inhalation into the body and reaction after a certain period of time Slot Aging by exhaust pipe A Slot The reaction mixture is then allowed to overflow and aged. Slot is the third reaction Slot and aging Slot The third aging Slot may be also possible.

[0133] Step 310: The target substance precipitate is dissolved to obtain a first solution.

[0134] In some embodiments, a leaching agent may be added to the target substance precipitate to dissolve it. Specifically, a leaching agent may be added to the target substance precipitate and dissolved until the pH is in the third range, to obtain a solution containing the target substance. The leaching agent includes at least a reducing agent, a first acid, and water. For more details regarding the leaching agent, the above description can be referred to, and detailed description thereof will be omitted here. In some embodiments, the third range may be pH=0 to 4. Preferably, the third range may be pH=0.5 to 3.5. Preferably, the third range may be pH=1.0 to 3.5. Preferably, the third range may be pH=1.5 to 3.0. Preferably, the third range may be pH=2.0 to 2.5. In some embodiments, the solution containing the target substance may be a solution containing one or more of nickel ions, cobalt ions, and manganese ions.

[0135] In some embodiments, a fourth alkaline solution may be added to the solution containing the target substance to adjust the pH of the solution. Specifically, an appropriate amount of the fourth alkaline solution may be added to the solution containing the target substance until the pH is in a fourth range to obtain the first solution. In some embodiments, the fourth alkaline solution may be a sodium hydroxide solution. The amount of the fourth alkaline solution added is determined by the pH of the solution. When the fourth alkaline solution is added, the addition of the fourth alkaline solution may be controlled so as to stop when the pH of the solution is in the fourth range. In some embodiments, the fourth range may be pH=4.5-6.5. Preferably, the fourth range may be pH=4.8-6.3. Preferably, the fourth range may be pH=5.0-6.0. Preferably, the fourth range may be pH=5.2-5.8. Preferably, the fourth range may be pH=5.4-5.6. The first solution may be a solution containing one or more of nickel ions, cobalt ions, and manganese ions.

[0136] Step 320: Third Reaction Slot The reaction temperature within the reactor was maintained at a third temperature above room temperature.

[0137] Third reaction Slot The volume of the third reaction may be set by the manufacturing process requirements or the supply amount of the reaction material. Slot The volume may be 50L, 80L or 100L.

[0138] The third temperature may be higher than room temperature. In some embodiments, the third temperature may be any value between 50 and 90°C. Preferably, the third temperature may be any value between 52 and 88°C. Preferably, the third temperature may be any value between 55 and 86°C. Preferably, the third temperature may be any value between 58 and 83°C. Preferably, the third temperature may be any value between 60 and 80°C. Preferably, the third temperature may be any value between 62 and 78°C. Preferably, the third temperature may be any value between 65 and 76°C. Preferably, the third temperature may be any value between 67 and 73°C. Preferably, the third temperature may be any value between 69 and 71°C. Preferably, the third temperature may be 50°C. Preferably, the third temperature may be 55°C. Preferably, the third temperature may be 60°C. Preferably, the third temperature may be 65°C. Preferably, the third temperature may be 70°C. Preferably, the third temperature may be 75° C. Preferably, the third temperature may be 80° C. Preferably, the third temperature may be 85° C. More preferably, the third temperature may be 90° C. In some embodiments, the third reaction Slot Heating the third reaction Slot The reaction temperature in the third reaction chamber may be maintained at a third temperature. Slot The heating method of may include, but is not limited to, electric heating, steam heating, heat transfer oil circulation heating, or far infrared heating in the present invention. Since the third temperature is higher than the crystallization temperature of the prior art, crystals that are easy to crystallize and have large crystal grains are obtained.

[0139] Step 330: The first solution and the fluorine-containing precipitant are respectively subjected to a third reaction at appropriate flow rates. Slot After inhaling and reacting for 5 hours, the third reaction Slot During the fifth hour, the reaction is stably maintained at the third temperature, and the flow rate of the fluorine-containing precipitant is adjusted to cause the third reaction to overflow. Slot The fluorine ion concentration of the reactant in is stabilized within a first concentration range.

[0140] Before inhaling the first solution, the third reaction Slot In some embodiments, a suitable amount of a fluorine-containing precipitant may be added as a bottom solution to the reaction mixture during the reaction. Slot The concentration of fluorine ions in may be 0.01 to 0.10 mol / L. Preferably, the concentration of fluorine ions may be 0.012 to 0.09 mol / L. Preferably, the concentration of fluorine ions may be 0.013 to 0.06 mol / L. Preferably, the concentration of fluorine ions may be 0.014 to 0.04 mol / L. Preferably, the concentration of fluorine ions may be 0.015 to 0.02 mol / L.

[0141] The flow rates of the first solution and the fluorine-containing precipitant may be set according to the manufacturing process requirements, and the first solution and the fluorine-containing precipitant are reacted for 5 hours by setting an appropriate flow rate. Slot For example, in some embodiments, the third reaction Slot The flow rate of the first solution is 40-300 mL / min, and the flow rate of the fluorine-containing precipitant is 50 L. Slot The fluorine ion concentration of the reactant in is controlled within a first concentration range or a measurement error range (for example, the measurement error tolerance of the fluorine ion concentration range may be ±0.0005 mol / L, i.e., the fluorine ion concentration range may be 0.0095 to 0.1005 mol / L), and for example, the flow rate of the fluorine-containing precipitant is 5 to 100 mL / min. Slot When the first solution is introduced into the third reaction vessel, the feed pipe of the first solution is connected to the Slot The third reaction Slot When fluorine-containing precipitants are sucked into the reactor, the feed pipe for the fluorine-containing precipitants must be connected to the third reactor. Slot As shown in FIG. 8, the first solution and the fluorine-containing precipitant are respectively pumped into the reaction vessel by feed pump A and feed pump B. Slot (i.e., the third reaction Slot ) and feed tube A and feed tube B are Slot In some embodiments, the third reaction Slot is the third reactionSlot The apparatus may include an agitation module for agitating the first solution and the fluorine-containing precipitant within the apparatus.

[0142] In some embodiments, the first concentration range may be a fluorine ion concentration of 0.005 to 0.1 mol / L. Preferably, the first concentration range may be a fluorine ion concentration of 0.010 to 0.099 mol / L. Preferably, the first concentration range may be a fluorine ion concentration of 0.020 to 0.095 mol / L. Preferably, the first concentration range may be a fluorine ion concentration of 0.030 to 0.090 mol / L. Preferably, the first concentration range may be a fluorine ion concentration of 0.040 to 0.080 mol / L. Preferably, the first concentration range may be a fluorine ion concentration of 0.050 to 0.070 mol / L. More preferably, the first concentration range may be a fluorine ion concentration of 0.055 to 0.060 mol / L. In some embodiments, stabilizing the fluorine ion concentration of the solution in the first concentration range may mean that the fluorine ion concentration of the solution is always at a value within the first concentration range, or may fluctuate within the first concentration range. For example, when the first concentration range is 0.01 to 0.02 mol / L, the fluorine ion concentration of the solution is 0.01 mol / L, 0.011 mol / L, 0.012 mol / L, 0.013 mol / L, 0.014 mol / L, 0.015 mol / L, 0.016 mol / L, 0.017 mol / L, 0.018 mol / L, 0.019 mol / L, or fluctuates within the range of 0.01 to 0.02 mol / L, and the fluorine ion concentration of the solution is considered to be stabilized in the first concentration range. SlotWhen the fluorine-containing precipitant is inhaled, the fluorine ion concentration of the solution is measured in real time by a fluorine ion meter to control the inhalation speed of the fluorine-containing precipitant, thereby maintaining the fluorine ion concentration of the solution within the first concentration range or the measurement error range (for example, the measurement error tolerance of the fluorine ion concentration range is ±0.0005 mol / L, that is, the fluorine ion concentration range may be 0.0095 to 0.1005 mol / L). The inhalation speed of the fluorine-containing precipitant is, that is, the fifth flow rate. For example, when the first concentration range is 0.010 to 0.015 mol / L and the flow rate of the fluorine-containing precipitant is 10 ml / min, if the fluorine ion concentration of the solution is lower than 0.010 mol / L, it is necessary to appropriately increase the flow rate of the fluorine-containing precipitant to increase the fluorine ion concentration of the solution to within the range of 0.010 to 0.015 mol / L; on the other hand, when the flow rate of the fluorine-containing precipitant is 40 ml / min, if the fluorine ion concentration of the solution exceeds 0.015 mol / L, it is necessary to appropriately decrease the flow rate of the fluorine-containing precipitant to decrease the fluorine ion concentration of the solution to within the range of 0.010 to 0.015 mol / L.

[0143] In some embodiments, the fifth hour may be 2 to 10 h. Preferably, the fifth hour may be 2.5 to 8.0 h. Preferably, the fifth hour may be 3.0 to 7.0 h. Preferably, the fifth hour may be 4.5 to 6.5 h. Preferably, the fifth hour may be 5.0 to 6.0 h. Preferably, the fifth hour may be 5.3 to 5.7 h. Preferably, the fifth hour may be 3 h. Preferably, the fifth hour may be 4 h. Preferably, the fifth hour may be 5 h. Preferably, the fifth hour may be 6 h. Preferably, the fifth hour may be 7 h. More preferably, the fifth hour may be 8 h. Third Reaction Slot The volume and location of the spillway (e.g., the spillway is located in the third reaction Slot The reaction materials are then transferred to the third reaction Slot After the reaction is complete for 3 to 8 hours, the third reaction Slot From the first aging Slot Let it overflow.

[0144] Third reaction Slot The first solution and the fluorine-containing precipitant are continuously drawn into the reactor to react continuously, and the above mixture is then subjected to a third reaction. Slot The first solution is allowed to stagnate for 2 to 10 hours within the reaction vessel to allow sufficient reaction and precipitation, thereby enabling continuous treatment of the first solution.

[0145] Step 340: Third Reaction Slot The overflow mixture is aged and the aging temperature is maintained at the third temperature and aged for a sixth hour.

[0146] This aging process is called the third aging process. Slot In some embodiments, the third aging step may be performed within Slot Heat the material for the third aging process. Slot The aging temperature in the third aging step may be maintained at a third temperature. Slot The heating method may include, but is not limited to, electric heating, steam heating, heat transfer oil circulation heating, or far infrared heating in the present invention. For details about the third temperature, refer to the description of step 320, and detailed description will be omitted here.

[0147] In some embodiments, the sixth hour may be 0.5 to 2 hours. Preferably, the sixth hour may be 0.8 to 1.8 hours. Preferably, the sixth hour may be 1.0 to 1.6 hours. Preferably, the sixth hour may be 1.2 to 1.4 hours. Preferably, the sixth hour may be 0.5 hours. Preferably, the sixth hour may be 1 hour. Preferably, the sixth hour may be 1.5 hours. More preferably, the sixth hour may be 2 hours.

[0148] Aging the fully reacted mixture for a sixth hour promotes grain growth of the precipitated crystals in the reacted mixture and makes the grain size distribution more uniform.

[0149] Step 350: After the aged mixture is allowed to stand for a seventh hour, a third separation step is performed to obtain a second impurity and a target solution.

[0150] This standing step is carried out in a second buffer tank, and the aged mixture is sucked into the second buffer tank and allowed to stand. In some embodiments, the seventh time may be 0.5 to 2 h. Preferably, the seventh time may be 0.8 to 1.8 h. Preferably, the seventh time may be 1.0 to 1.6 h. Preferably, the seventh time may be 1.2 to 1.4 h. Preferably, the seventh time may be 0.5 h. Preferably, the seventh time may be 1 h. Preferably, the seventh time may be 1.5 h. More preferably, the seventh time may be 2 h.

[0151] In some embodiments, the mixture after standing may be subjected to a third separation step to obtain a second impurity and a target solution. Specifically, the third separation step may be a solid-liquid separation step. For example, the third separation method may include filtration, gravity sedimentation, centrifugal sedimentation, pressure filtration, etc. In some embodiments, the second impurity may include at least one or more of calcium fluoride, magnesium fluoride, and lead fluoride. In some embodiments, the target solution may be a solution containing one or more of nickel ions, cobalt ions, and manganese ions. In some embodiments, the aged mixture may be subjected to the third separation step directly without standing the aged mixture.

[0152] In some embodiments, the target solution may be further processed to obtain a precursor precipitate. Specifically, a third alkaline solution may be added to the target solution to obtain a precursor precipitate. In some embodiments, the third alkaline solution may be the same as the fourth alkaline solution. For example, the third alkaline solution may be a sodium hydroxide solution. In some embodiments, the precursor precipitate and the lithium hydroxide crystals or lithium carbonate crystals may be further sintered to obtain a lithium battery cathode material.

[0153] In the above method, a third reaction of the first solution and a fluorine-containing precipitant is performed. SlotBy controlling the suction flow rate to the reactor, the reaction temperature, the reaction time, and the aging time, the crystal grains can be grown sufficiently to large crystal grains, making it easier to carry out the third separation step, reducing the amount of water used for washing in the third separation step and the washing time, while reducing the waste of nickel-cobalt-manganese ions in the washing step, and further improving the recovery rate of nickel-cobalt-manganese.

[0154] Hereinafter, the method for removing calcium ions, magnesium ions, and lead ions in the recovery process of lithium battery positive electrode materials will be described in detail with reference to Examples 5 and 6. The reaction conditions, reaction materials, and amounts of reaction materials used in Examples 5 and 6 are merely for explaining the method for removing calcium ions, magnesium ions, and lead ions in the recovery process of waste positive electrode materials of lithium batteries, and do not limit the scope of protection of the present invention. Example 5 is an example using the impurity removal method of FIG. 3. Example 6 is an example of an impurity removal method for mass-producing impurities in target substance precipitation. Example 6 is a control group of Example 5. Example 5

[0155] Step 1: Dissolve sulfuric acid and hydrogen peroxide solution for precipitating the target substance containing nickel, cobalt, and manganese ions, and react with each other while controlling the pH value of the solution to 3.2 to obtain a solution containing the target substance. Add NaOH solution into the solution containing the target substance to adjust the pH value of the mixture to 5.2 to obtain a first solution.

[0156] Step 2: The first solution with a pH value of 5.2 is pumped through a peristaltic pump to 50 L of the third reactor. Slot The flow rate was controlled at 100 mL / min. Slot The reaction temperature in the reactor was controlled at 90°C, and 0.96 mol / L NaF solution was introduced into the reactor at a flow rate of 20 mL / min. Slot The fluorine ion content of the reaction solution was measured every 30 minutes, and the flow rate of the NaF solution was adjusted according to the measured value to control the fluorine ion content to 0.01 mol / L to 0.015 mol / L. After the reaction was sufficiently carried out for 5 hours, the third reaction SlotThe mixture is poured out from the overflow port of the third aging process. Slot A total of 30 L of the first solution was aspirated in this step.

[0157] Step 3: Third aging Slot The mixture was heated to maintain the aging temperature constant at 90°C, and the mixture was subjected to the third aging process. Slot Aging is then carried out for 1 hour in the refrigerator.

[0158] Step 4: Aging the mixture for the third time Slot The supernatant was clear and no floating matter was observed.

[0159] Step 5: The aged mixture was filtered through a filter press and the wet slug was collected and then washed in the lab.

[0160] Step 6: The filtrate was collected and the volume of the resulting filtrate was 41.5 L.

[0161] Step 7: The first solution, the filtrate and the slag were subjected to ICP measurement, and the slag was subjected to SEM measurement. Example 6

[0162] Step 1: Dissolve concentrated sulfuric acid and hydrogen peroxide solution for precipitating the target substance containing nickel, cobalt, and manganese ions, and control the pH value of the solution to 3.2 to react with each other to obtain a solution containing the target substance. Add NaOH solution into the solution containing the target substance to make the pH value of the mixture 5.2 to obtain a first solution.

[0163] Step 2: Add 40 L of the first solution with a pH value of 5.2 to 50 L of the third reaction mixture. Slot Add it all at once to the third reaction Slot The reaction temperature inside was stabilized at 90°C.

[0164] Step 3: 81 g of NaF solid was added and stirred for 1 hour, then the heating was stopped and the mixture was allowed to cool naturally to room temperature.

[0165] Step 4: After leaving it for 24 hours, the supernatant was observed and there was white floating matter on the surface that could not be precipitated.

[0166] Step 5: The aged mixture was filtered through a filter press and the wet slug was collected and then washed in the lab.

[0167] Step 6: The filtrate was collected and the volume of the resulting filtrate was 39.5 L.

[0168] Step 7: The first solution, the filtrate and the slag were subjected to ICP measurement, and the slag was subjected to SEM measurement.

[0169] From the ICP measurement results of Examples 5 and 6, the data in Table 2 can be obtained. ICP analysis results JPEG0007606612000002.jpg27170

[0170] The calcium ion removal rates of Examples 5 and 6 can be further calculated from Table 2.

[0171] Calcium ion removal rate in Example 5: Ca removal rate = (Ca content of first solution x volume of original solution - Ca content of filtrate x volume of filtrate) / (Ca content of original solution x volume of original solution) = (294 x 30 L - 3.38 x 41.5 L) / (294 x 30 L) x 100% = 98.4%

[0172] Calcium ion removal rate in Example 6: Ca removal rate = (Ca content in stock solution x volume of stock solution - Ca content in filtrate x volume of filtrate) / (Ca content in stock solution x volume of stock solution) = (294 x 40 L - 21 x 39.5 L) / (294 x 40 L) = 92.9%

[0173] Calcium in Examples 5 and 6 Yi According to the calculation results of the calcium ion removal rate, the calcium ion removal rate of Example 5 was higher than that of Example 6, and it was found that the calcium ion removal effect of the first solution of Example 5 was better.

[0174] 7A is an SEM image of the slag of the fifth embodiment of the present invention. FIG. 7B is an SEM image of the slag of the sixth embodiment of the present invention. According to FIG. 7A and FIG. 7B, it can be seen that the slag of the fifth embodiment has a clear cubic crystal structure, while the crystal grains of the slag of the sixth embodiment are so fine that the crystal grain structure cannot be identified. Compared with the method of the sixth embodiment, the crystal grains of the precipitate obtained after removing impurities from the first filtrate by the method of the fifth embodiment are larger.

[0175] The comparison results between Example 5 and Example 6 are as follows. In Example 5, the reaction temperature was maintained at 90°C, the fluorine ion content was controlled to 0.01 mol / L to 0.015 mol / L, and the first solution was fully reacted for 5 hours, aged for 1 hour, and left to stand for 1 hour, thereby performing an impurity removal treatment on the first solution. In Example 6, the reaction materials were added at once at 90°C, reacted for 1 hour, and left to stand for 24 hours, thereby performing an impurity removal treatment on the first solution. According to the comparison results, in Example 5, the same reaction temperature as in Example 6 was used, and the feed rate for adding the first solution and the fluorine ion content, the long reaction time, and the aging time were controlled in cooperation, which made the crystal grains of the precipitate generated larger, made the precipitate easier to filter and wash, improved the calcium ion removal rate, and made the impurity removal effect better.

[0176] The impurity removal method and the lithium recovery method shown in Figs. 1 to 3 may be carried out alone or simultaneously. The actual impurity removal process is determined according to the type of impurity. For example, when the impurities contained in the waste positive electrode material of the lithium battery are only one or more of iron ions, aluminum ions, and copper ions, the impurities can be removed from the waste positive electrode material of the lithium battery by carrying out only the impurity removal method shown in Fig. 1. Also, for example, when the impurities contained in the waste positive electrode material of the lithium battery are not only one or more of iron ions, aluminum ions, and copper ions, but also one or more of calcium ions, magnesium ions, and lead ions, the impurities can be removed from the waste positive electrode material of the lithium battery by carrying out the impurity removal method and the lithium recovery method shown in Figs. 1 to 3. Furthermore, for example, when the impurities contained in the waste positive electrode material of the lithium battery are only one or more of calcium ions, magnesium ions, and lead ions, the impurities can be removed from the waste positive electrode material of the lithium battery by carrying out the impurity removal method shown in Figs. 2 and 3.

[0177] The beneficial effects of the embodiments of the present invention include, but are not limited to, the following effects: (1) By carrying out the precipitation reaction at a reaction temperature higher than room temperature and at a certain pH, a precipitate with a large particle size, high crystallinity, and low water content can be obtained, so that the precipitation filtration and washing process can be carried out more efficiently, easily, and quickly, the amount of water used in the washing process can be reduced, and the recovery rate of nickel-cobalt-manganese in the recovery process of waste positive electrode materials of lithium batteries can be improved. (2) By removing lithium ions before preparing the positive electrode material precursor precipitate of lithium batteries, the purpose of lithium recovery can be achieved, and the influence on the control of reaction parameters in the subsequent impurity removal method process can be reduced, and the recovery rate of nickel-cobalt-manganese can be improved. Note that the beneficial effects may vary from embodiment to embodiment, and the beneficial effects that may be obtained from different embodiments may be one or a combination of two or more of the above effects, or other beneficial effects that may be obtained.

[0178] It should be noted that the above examples are only used to explain the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can understand that, without departing from the spirit and scope of the technical solutions, modifications or equivalent replacements of the technical solutions of the present invention are within the scope of the present invention.

Claims

1. A method for removing and treating impurities in a recovery process of waste positive electrode materials of lithium batteries, comprising: A step (1) of maintaining a first reaction tank at a first temperature higher than room temperature, drawing a leachate of a lithium battery waste positive electrode material and a first alkaline solution into the first reaction tank at a predetermined flow rate, and controlling the drawing flow rate of the first alkaline solution to create a stable environment of a first pH value, thereby precipitating and removing iron ions, aluminum ions, and at least a part of copper ions, thereby obtaining a first filtrate; (2) maintaining a second reaction tank at a second temperature higher than room temperature, drawing the first filtrate, the complexing agent and the second alkaline solution into the second reaction tank at respective predetermined flow rates, and controlling the drawing flow rate of the second alkaline solution to achieve a first pH range and remove lithium ions, thereby separating a second filtrate containing lithium ions, and obtaining a target substance precipitate; (3) dissolving the target substance precipitate to obtain a first solution; and (4) controlling a third reaction tank at a third temperature higher than room temperature, drawing the first solution and the fluorine-containing precipitant into the third reaction tank at respective predetermined flow rates, and precipitating and removing calcium ions, magnesium ions and at least a part of lead ions within a predetermined fluorine ion concentration range by controlling the drawing flow rate of the fluorine-containing precipitant to obtain a target solution, The impurity removal and treatment method is carried out in a continuously operable overflow reactor.

2. a step of maintaining the first reaction tank at a first temperature higher than room temperature, drawing a leaching solution of a waste positive electrode material of a lithium battery and a first alkaline solution into the first reaction tank at a predetermined flow rate, and controlling the drawing flow rate of the first alkaline solution to create a stable environment of a first pH value, thereby precipitating and removing iron ions, aluminum ions and at least a part of copper ions, and obtaining a first filtrate, overflowing the first reaction vessel after reacting for a first period of time, and then carrying out a first separation step to obtain a precipitate containing the iron ions, aluminum ions, and at least a portion of the copper ions, and the first filtrate; 2. The method of claim 1, wherein during the first time period, the reaction is maintained at a stable first temperature and the intake flow rate of the first alkaline solution is adjusted to stabilize the reaction at the first pH value.

3. The method described in claim 2, further comprising the step of aging the mixture overflowing from the first reaction tank before performing the first separation step, maintaining the aging temperature at the first temperature and aging for a second time.

4. a step of maintaining the second reaction tank at a second temperature higher than room temperature, drawing the first filtrate, the complexing agent and the second alkaline solution into the second reaction tank at respective predetermined flow rates, and controlling the drawing flow rate of the second alkaline solution to achieve a first pH range and remove lithium ions, and separating the second filtrate containing lithium ions to obtain a target substance precipitate, overflowing the second reaction tank after reacting for a third time, and then carrying out a second separation step to obtain a second filtrate containing the target substance precipitate and the lithium ions; 2. The method of claim 1, wherein during the third period of time, the reaction is maintained at a stable second temperature and the intake flow rate of the second alkaline solution is adjusted to maintain the reaction at a stable first pH range.

5. The method described in claim 4, further comprising the step of aging the mixture overflowing from the second reaction tank before performing the second separation step, maintaining the aging temperature at the second temperature, and aging for a fourth hour.

6. The step of dissolving the target substance precipitate to obtain a first solution includes: adding a leaching agent containing at least a reducing agent, a first acid, and water to the target substance precipitate, dissolving the target substance until the pH falls within a third range, thereby obtaining a solution containing the target substance; 2. The method according to claim 1, further comprising the step of: adding an appropriate amount of a fourth alkaline solution to the solution containing the target substance until the pH is in a fourth range to obtain the first solution.

7. a step of controlling the third reaction tank to a third temperature higher than room temperature, drawing the first solution and the fluorine-containing precipitant into the third reaction tank at respective predetermined flow rates, and precipitating and removing calcium ions, magnesium ions and at least a part of lead ions within a predetermined fluorine ion concentration range by controlling the drawing flow rate of the fluorine-containing precipitant to obtain a target solution, overflowing the third reaction tank after reacting for a fifth time, and then carrying out a third separation step to obtain a precipitate containing the calcium ions, magnesium ions and at least a portion of the lead ions and the target solution; 2. The method of claim 1, wherein during the fifth time period, the reaction is maintained at a stable third temperature and the fluorine ion concentration of the reactant in the third reaction tank is stabilized within a predetermined concentration range by adjusting the intake flow rate of the fluorine-containing precipitant.

8. Before carrying out the third separation step, aging the overflow mixture from the third reactor, maintaining the aging temperature at the third temperature and aging for a sixth time; 8. The method of claim 7, further comprising: allowing the aged mixture to stand for a seventh hour.

9. Before subjecting the leachate of the waste positive electrode material of the lithium battery to a precipitation treatment, The method according to any one of claims 1 to 8, further comprising the steps of: adding a leaching agent, which comprises at least a reducing agent, a first acid and water, to the waste positive electrode material of a lithium battery, dissolving the waste positive electrode material until the pH is in a second range; and then carrying out a fourth separation step to obtain a third impurity and a leachate of the waste positive electrode material of the lithium battery.

10. 9. The method of any one of claims 1 to 8, further comprising the step of adding a third alkaline solution to the target solution to obtain a precursor precipitate.

11. 9. The method according to any one of claims 1 to 8, wherein the first pH value is any value between pH=5.5 and 6.7, or the first pH range is between pH=10.5 and 11.

8.

12. 9. The method according to claim 1, wherein the first temperature is any value between 50 and 90°C, the second temperature is any value between 40 and 70°C, or the third temperature is any value between 50 and 90°C.

13. 9. The method according to any one of claims 1 to 8, wherein the first alkaline solution comprises lithium hydroxide.

14. 9. The method according to any one of claims 1 to 8, wherein the second alkaline solution comprises lithium hydroxide.

15. 7. The method of claim 6, wherein the third range is pH=0-4 or the fourth range is pH=4.5-6.5.

Images