WO2022000830A1

WO2022000830A1 - Method and device for recycling cobalt metal in lithium-ion battery waste

Info

Publication number: WO2022000830A1
Application number: PCT/CN2020/117684
Authority: WO
Inventors: 王吕阳; 徐婷婷
Original assignee: 深圳技术大学
Priority date: 2020-07-01
Filing date: 2020-09-25
Publication date: 2022-01-06
Also published as: CN111647752A

Abstract

A method and device for recycling a cobalt metal in a lithium-ion battery waste. The recycling method comprises the following steps: step one, mixing a solid waste with an alkali metal solution, fully reacting the mixture, and chelating same to form a cobalt-organic matter intermediate; step two, performing solid-liquid separation on a solution containing the cobalt-organic matter intermediate and a solid mixture; and step three, performing a hydrothermal reaction on the solution containing the cobalt-organic matter intermediate, and crystalizing to form the cobalt hydroxide powder, wherein the solid waste in the step one is a waste containing a cobalt element in a lithium-ion battery; when the solid waste is mixed with the alkali metal solution, grinding and drying pretreatments are carried out; when the solid-liquid separation in the step two is performed, washing and/or alcohol washing is performed on the solid surface. According to the present method, in a closed system, the alkali metal solution is used to react with the solid mixture for extracting the cobalt element. The reaction condition is mild, and no waste is discharged to the external environment. The solvent therein can be recycled. The present method is fast in reaction and low in cost, and is a simple, convenient, and energy-saving method for effectively recycling the cobalt element in the lithium battery.

Description

A kind of cobalt metal recovery method and equipment of lithium ion battery waste

technical field

The invention relates to a method for recovering cobalt metal, in particular to a method and equipment for recovering cobalt in a mixture of electrode materials, binders and conductive carbon materials.

Background technique

At present, lithium ion batteries (LIB) have been widely used in electronic equipment, electric vehicles ( EV) and electrochemical power storage systems. With the upgrading of consumer electronic products and a large number of power batteries entering the end-of-life cycle in the future, the number of used lithium batteries will rise sharply, and the lithium battery recycling outbreak is imminent. Power batteries are about to usher in the first wave of decommissioning. If they are not properly handled, it will cause environmental pollution and waste of resources. Although LIBs are technically considered "green," the electrolyte inside LIBs is flammable and can release toxic gases such as HF if the LIBs burn or are exposed to air or water. In addition, Co and Ni used in LIB are also classified as carcinogenic, mutagenic and toxic to reproduction. Therefore, recycling cathode materials in waste lithium batteries can effectively reduce environmental pollution and pathogenic risks, and improve the recycling efficiency of raw materials. From an economic point of view, LIB recycling is also very important for saving resources and recovering high-cost metals, so the recycling of used LIBs is of great significance. How to reasonably recycle and utilize the valuable elements of waste lithium-ion batteries, improve resource reuse rate, and reduce environmental pollution has become an urgent problem to be solved, which has important environmental and economic significance. Currently, there is no large-scale recycling business in the world because the battery consumption in the past was not sufficient to generate economic benefits for the business. Nonetheless, untreated used batteries are left behind, potentially becoming a serious environmental problem and undermining the gains in promoting the adoption of electric vehicles. The purpose of recycling is to separate the components of waste products into different parts and reintroduce these parts into production. The goal of recycling is to reduce waste and dispose of hazardous substances in an energy-efficient and economical way.

Generally, based on the reaction characteristics, the treatment process of waste LIB can be divided into three categories: physical method, chemical method and biological method. Waste lithium batteries have diverse compositions and huge differences in material properties. In the process of recycling, the batteries need to be pretreated, disassembled and classified, and then use different technologies to recover and purify valuable metals. Physical recycling processes are often used as pretreatment to separate anode materials from other components such as current collectors and binders, thereby reducing impurities and facilitating subsequent recycling. And according to the different physical properties of LIB (including density, solubility, magnetic properties, etc.), the commonly used physical recovery methods include mechanical separation and organic solvent dissolution. There are many methods for leaching valuable metals from the positive electrode material obtained by pretreatment, the most common method is chemical treatment, such as acid leaching, alkali leaching, etc., and then recovering and purifying valuable metal elements. The representative recovery and purification methods mainly include flotation method, precipitation method, solvent extraction method and electrodeposition method. There is also a bioleaching method, such as the recovery of cobalt and lithium from spent lithium-ion batteries by ferrooxidans acidophilus. Although this method provides a new method for the recovery of cobalt element, the leaching rate of ferrooxidans acidophilus to lithium cobaltate is very low, so it is necessary to cultivate strains with higher leaching rate in the future. Compared with other methods, the bioleaching method has the advantages of less acid consumption, low cost, simple operation, and small environmental impact.

The traditional lithium-ion battery recycling technologies include pyrometallurgy, hydrometallurgy and other processes. Without exception, the positive electrode materials are crushed and screened, and then high-temperature incineration, acid leaching, alkali leaching or acid-base combined use are used to dissolve valuable materials. The metals are then purified and recovered by techniques such as precipitation and extraction to recover cobalt, lithium and other elements. Although these process technologies have successfully recovered valuable elements in waste lithium batteries and obtained high-purity products, they also cause a certain waste of resources and energy, and the recovery process is complicated and difficult to scale up. The industrial-scale recovery process of spent LIB is mainly based on pyrometallurgical methods, which are simple to operate but require higher energy consumption and generate secondary pollution.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and equipment for recovering cobalt metal from lithium ion battery waste materials in view of the above-mentioned problems in the prior art.

Purpose of the present invention is achieved through the following technical solutions:

A method for recovering cobalt metal from lithium ion battery waste, comprising the following steps: step 1, mixing solid waste with an alkali metal solution, fully reacting, and chelating to form a cobalt-organic intermediate; The mixture of the solution and the solid is subjected to solid-liquid separation; in step 3, a hydrothermal reaction is performed on the solution containing the cobalt-organic intermediate to crystallize cobalt hydroxide powder; wherein, the solid waste described in step 1 is a lithium ion battery containing The waste of cobalt element is subjected to pretreatment of pulverization and drying when it is mixed with the alkali metal solution; during the solid-liquid separation in step 2, the surface of the solid object is washed with water and/or alcohol.

Preferably, the first step further includes a step of preparing an alkali metal solution, under the protection of an inert gas, completely dissolving the alkali metal in the solvent to obtain an alkali metal solution, wherein the concentration of the alkali metal solution is greater than 10 -5 mol/L, the solvent is an organic solvent or liquid ammonia; the alkali metal is at least one of lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, and barium; alkali The molar ratio of metal to solvent is 1:0.0001-10.

Preferably, the organic solvent is at least one of methylamine, ethylamine, ethylenediamine, propylamine, propylenediamine, butylamine, butanediamine and polyvalent organic amines.

Preferably, the fully reacted solution in the first step is a free electron solution without protons.

Preferably, the solid wastes are electrode materials, binders and conductive carbon materials.

The present invention is a cobalt metal recovery equipment for lithium ion battery waste, comprising a stirring tank, a solid-liquid separation tank and a hydrothermal reaction tank connected by pipelines in sequence; the solid-liquid separation tank includes a separation tank body, and a Centrifugal bucket, the upper part of the centrifugal bucket is connected with the output shaft of the centrifugal motor through the spokes provided, the lower end of the centrifugal bucket is provided with a solid discharge pipe, and the outer circumference of the solid discharge pipe is sealed with the tank body through bearings. Rotational connection; the lower end of the solid discharge pipe is provided with a discharge port that deviates to one side, and a mandrel is penetrated in the center, and an outer conical baffle is arranged above the mandrel, and the outer conical baffle is connected to the solid-liquid When separating, it is in sealing contact with the inner cone surface of the centrifugal bucket to prevent the solids from falling; a discharge cylinder is arranged below the ejector rod. When the discharge cylinder is raised, the outer cone baffle is removed by the ejector rod. The solid material is discharged from the gap between the outer cone baffle and the inner cone surface of the centrifugal bucket to the solid discharge pipe.

Preferably, a cleaning agent input pipe is also provided above the tank to inject water or alcohol for cleaning; the lower end of the centrifugal bucket is provided with a conical baffle for blocking the solution from entering the bearing; the discharge There is a solid recovery box below the mouth.

Preferably, the stirring tank includes a stirring tank body, a stirring motor is arranged above the stirring tank body, a stirring rod is connected to the downward driving of the stirring motor, and a stirring blade is provided at the lower end of the stirring rod; The top of the stirring tank is also provided with an alkali metal input pipe, a solvent input pipe, a first inert gas input pipe, a first vacuuming pipe and a solid material isolation tank; the solid material isolation tank includes an isolation tank, which is located in the isolation tank The discharge valve below the body, and the feed valve, the second inert gas input pipe and the second vacuum pipe are arranged above the isolation tank.

Preferably, the hydrothermal reaction tank includes a hydrothermal tank body, a liquid inlet valve disposed above the hydrothermal tank body, and a crystallization discharge valve disposed below the hydrothermal tank body; the crystallization discharge valve is also connected with a Crystallization recovery tube; the lower side of the crystallisation recovery tube is provided with a filter screen to filter the residual solution after the hydrothermal reaction to the solution recovery box.

Preferably, there are at least two of the hydrothermal reaction tanks, and further includes a frame, a turntable disposed above the frame, and a drive mechanism for driving the turntable, and the hydrothermal reaction tanks are evenly installed on the on the turntable.

The invention also discloses a solid-liquid separation tank, which comprises a separation tank body, a centrifugal barrel arranged in the separation tank body, the upper part of the centrifugal barrel is connected with the output shaft of the centrifugal motor through the spokes provided, and the centrifugal barrel is connected with the output shaft of the centrifugal motor. The lower end of the solid discharge pipe is provided with a solid discharge pipe, and the outer circumference of the solid discharge pipe is sealed and rotated with the tank body through a bearing; The top of the ejector rod is provided with an outer conical baffle, and the outer conical baffle is kept in sealing contact with the inner conical surface of the centrifuge bucket during solid-liquid separation to prevent the solid from falling; There is a discharge cylinder below. When the discharge cylinder rises, the outer conical baffle is raised by the ejector rod, and the solid material flows from the gap between the outer conical baffle and the inner cone of the centrifugal bucket to the solid discharge pipe. discharge.

Further, the top of the tank is also provided with a cleaning agent input pipe to inject water or alcohol for cleaning; the lower end of the centrifugal bucket is provided with a conical baffle for blocking the solution from entering the bearing; the discharge There is a solid recovery box below the mouth.

The invention also discloses a stirring tank, which comprises a stirring tank body, a stirring motor is arranged above the stirring tank body, a stirring rod is connected to the downward driving of the stirring motor, and a stirring blade is arranged at the lower end of the stirring rod The top of the stirring tank is also provided with an alkali metal input pipe, a solvent input pipe, a first inert gas input pipe, a first evacuating pipe and a solid material isolation tank; the solid material isolation tank includes an isolation tank, which is provided with The discharge valve under the isolation tank body, and the feed valve, the second inert gas input pipe and the second vacuum pipe are located above the isolation tank body.

The invention also discloses a hydrothermal reaction tank, which comprises a hydrothermal tank body, a liquid inlet valve disposed above the hydrothermal tank body, and a crystallization discharge valve disposed below the hydrothermal tank body; the crystallization discharge valve A crystal recovery pipe is also connected; a filter screen is arranged on the lower side of the crystal recovery pipe to filter the residual solution after the hydrothermal reaction to a solution recovery box.

Further, there are at least two or more of the hydrothermal reaction tanks, and also includes a frame, a turntable disposed above the frame, and a drive mechanism for driving the turntable, and the hydrothermal reaction tanks are evenly installed on the on the turntable. A turntable hydrothermal reaction equipment is formed.

Compared with the prior art, the beneficial effects of the present invention are: in a closed system, the alkali metal solution is used to react with the solid mixture of the electrode material, the binder and the conductive carbon material to extract the cobalt element, and the reaction conditions are mild and do not It is a simple and energy-saving method to effectively recover cobalt in lithium batteries by discharging waste to the external environment, and the solvent in it can be recycled and reused. The reaction is fast and the cost is low. The recovery equipment of the invention is used to recover the cobalt metal of the lithium ion battery waste material, which can be recovered industrially in large quantities.

Description of drawings

1 is a schematic diagram of steps in a specific embodiment of a cobalt metal recovery method for lithium ion battery waste according to the present invention;

2 is a schematic diagram of the overall structure in a specific embodiment of a cobalt metal recovery device for lithium ion battery waste according to the present invention;

Fig. 3 is a partial enlarged view of the stirring tank of the embodiment of Fig. 2;

Fig. 4 is a partial enlarged view of the solid-liquid separation tank of the embodiment of Fig. 2;

Fig. 5 is a partial enlarged view (turntable structure) of a plurality of hydrothermal reaction tanks of the embodiment of Fig. 2;

Fig. 6 is a partial enlarged view of a single hydrothermal reaction tank in Fig. 5;

FIG. 7 is a partial enlarged view of the turntable in FIG. 5 .

detailed description

The technical solutions of the present invention will be clearly and completely described below through the following embodiments. Obviously, the embodiments to be described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It is to be understood that, when used in this specification and the appended claims, the terms "comprising" and "comprising" indicate the presence of the described features, integers, steps, operations, elements and/or components, but do not exclude one or The presence or addition of a number of other features, integers, steps, operations, elements, components, and/or sets thereof.

It should also be understood that the terms used in the description of the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present invention. As used in the description of the embodiments of the invention and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly dictates otherwise.

As shown in Figure 1, a method for recovering cobalt metal from lithium ion battery waste of the present invention comprises the following steps: step 1, mixing the solid waste with an alkali metal solution, fully reacting, and chelating to form a cobalt-organic intermediate; step 2, Carry out solid-liquid separation on the solution containing the cobalt-organic intermediate and the solid mixture; step 3, perform a hydrothermal reaction on the solution containing the cobalt-organic intermediate to crystallize cobalt hydroxide powder; The solid waste is the waste containing cobalt element in the lithium ion battery, when mixed with the alkali metal solution, the pretreatment of pulverization and drying is carried out; in the solid-liquid separation in step 2, the surface of the solid object is washed with water and/or alcohol. 2. Described step 1, also comprises the preparation step of alkali metal solution, under the protection of inert gas, alkali metal is completely dissolved in solvent, obtains alkali metal solution, wherein, the concentration of described alkali metal solution is greater than 10- 5 mol/L, and the solvent is an organic solvent or liquid ammonia; the alkali metal is at least one of lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, and barium; the alkali metal The molar ratio to the solvent is 1:0.0001-10. The organic solvent is at least one of methylamine, ethylamine, ethylenediamine, propylamine, propylenediamine, butylamine, butanediamine and polyvalent organic amines. The fully reacted solution in the first step is a free electron solution without protons. The solid wastes are electrode materials, binders and conductive carbon materials.

The following are 7 specific embodiments of the recovery method of the present invention.

Example 1

The present embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) in a closed reaction vessel, under the protection of an inert gas, according to the molar ratio of alkali metal: the solvent is 1:0.0001-10, and the alkali metal is completely dissolved in the solvent to obtain an alkali metal solution ^{with a concentration greater than 10-5 mol/liter,} Wherein, the solvent is an organic solvent or liquid ammonia;

2) Under the protection of inert gas, according to weight parts, 1 weight part of battery waste (mainly a mixture of electrode material, binder and conductive carbon material) is dispersed in 0.1-10 weight parts of the alkali metal of step 1) In the solution, fully react to obtain a solid-liquid mixture;

3) Centrifuging the solid-liquid mixture in step 2), washing the solid material with water and/or alcohol, removing the residual alkali metal solution on the surface, and then hydrothermally heating the solution to obtain cobalt hydroxide powder.

In a specific embodiment, the alkali metal in step 1) is at least one of lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, and barium.

In a specific embodiment, the organic solvent in step 1) is at least one of methylamine, ethylamine, ethylenediamine, propylamine, propylenediamine, butylamine, butanediamine and polyvalent organic amine.

In a specific embodiment, the reaction solution in step 2) is a free electron solution in which no protons exist.

It should be noted that when the selected organic solvent is methylamine and/or ethylamine, liquid ammonia, because of its low boiling point, it is gaseous at normal temperature, therefore, the airtight container can be pressurized to make methylamine and/or ethylamine Amine and liquid ammonia are converted into liquid, and then the above-mentioned process steps are carried out. The size of the pressure can be selected by those skilled in the art, which is not limited in the present invention.

For ethylenediamine, propylamine, propylenediamine, butylamine, butanediamine and polyvalent organic amines that are liquid at room temperature, the above reaction can be carried out at room temperature.

It should be noted that, in order to ensure sufficient reaction in step 2) and to completely separate out the cobalt element, it is necessary to ensure that the alkali metal solution for the reaction is more than the solid mixture added.

Lithium cobaltate reacts with alkali metal solution. The reaction mechanism is that the cobalt-O oxygen bond in lithium cobaltate is first attacked by dissolved free electrons to form cobalt and oxygen double vacancies. At the same time, cobalt atoms are rapidly chelated by the solvent to form cobalt-organic compounds Intermediate. The cobalt-organic intermediate undergoes a hydrothermal reaction, and the crystal grows to form beta-phase cobalt hydroxide.

The method provided in this example, namely, in a closed system, utilizes an alkali metal solution to react with the mixture to extract cobalt element, the reaction conditions are mild, and there is no need to consume additional energy such as electric energy, which is an effective method for recovering cobalt.

Embodiment 2, this embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) under the protection of inert gas, according to the molar ratio lithium: ethylenediamine is 1:0.001, and metal lithium is completely dissolved in ethylenediamine to obtain an alkali metal solution ^{with a concentration greater than 10-5 mol/liter;}

2) under the protection of inert gas, according to weight parts, the mixture of 1 weight part of electrode material, binder and conductive carbon material is dispersed in the alkali metal solution of step 1) of 0.1-10 weight parts, fully reacted, A solid-liquid mixture is obtained;

3) Centrifuging the solid-liquid mixture in step 2), washing the solid material with water and alcohol in turn, removing the residue of the alkali metal solution on the surface, and then hydrothermally heating the solution to obtain cobalt hydroxide powder.

It should be noted that, in this specific embodiment, the alcohol used in step 3) alcohol washing is anhydrous ethanol.

The organic solvent ethylenediamine is liquid at normal temperature, so the reaction of the above steps can be carried out in this embodiment at normal temperature.

Embodiment 3, this embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) Under the protection of inert gas, the molar ratio of (sodium and potassium) :( methylamine and ethylamine) is 1: 10, the sodium and potassium metal was completely dissolved in methylamine and ethylamine, to give a concentration of greater than 10 ^{- 5} mol/liter alkali metal solution;

3) Centrifuging the solid-liquid mixture in step 2), washing the solid material alternately with water and alcohol, removing the residue of the alkali metal solution on the surface, and then hydrothermally heating the solution to obtain cobalt hydroxide powder.

It should be noted that, since methylamine and ethylamine are gases at normal temperature, in this embodiment, by pressurizing the airtight container, methylamine and ethylamine are liquefied, and then the alkali metal is dissolved.

Embodiment 4, this embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) Under the protection of inert gas, according to the molar ratio (beryllium, magnesium, barium): (propylamine, propylenediamine, butylamine) is 1:5, the metal beryllium, magnesium, barium are completely dissolved in propylamine, propylenediamine , in butylamine to obtain an alkali metal solution with a concentration greater than 10 ^{-5 mol/L;}

It should be noted that, in a specific implementation, the alcohol used in step 3) alcohol washing is absolute ethanol.

Embodiment 5, this embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) Under the protection of inert gas, according to the molar ratio (rubidium): (butylamine, butanediamine) is 1:0.11, the metal rubidium is completely dissolved in the mixed solution of butylamine and butanediamine, and the concentration is greater than 10 ^-5 mol/liter of alkali metal solution;

22) Under the protection of inert gas, according to weight parts, the mixture of 1 weight part of electrode material, binder and conductive carbon material is dispersed in the alkali metal solution of step 1) of 0.1-10 weight parts, fully reacted, A solid-liquid mixture is obtained;

The organic solvent butylamine and butanediamine are liquids at normal temperature, so the reaction of the above steps can be carried out in this embodiment at normal temperature.

Embodiment 6, this embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) Under the protection of inert gas, according to the molar ratio (beryllium, magnesium): (butanediamine) is 1:0.0001, metal beryllium and magnesium are completely dissolved in butanediamine, and the concentration is greater than ^10-5 mol/ liters of alkali metal solution;

3) The solid-liquid mixture of step 2) is centrifuged, and the solid material is washed with water and alcohol in turn to remove the alkali metal solution residue on the surface, that is, to obtain metal elemental cobalt, and then the solution is hydrothermally obtained to obtain cobalt hydroxide powder. .

The organic solvent butanediamine is liquid at normal temperature, so the reaction of the above steps can be carried out in this embodiment at normal temperature.

Embodiment 7, this embodiment discloses a method for recovering cobalt metal from lithium ion battery waste, and the specific steps are as follows:

1) under the protection of inert gas, according to the molar ratio of sodium: liquid ammonia is 1: 1.5, the metal sodium is completely dissolved in the liquid ammonia to obtain a concentration greater than ^10-5 mol/liter alkali metal solution;

It should be noted that liquid ammonia is a gas at normal temperature, so in this embodiment, the liquid ammonia is liquefied by pressurizing the airtight container, and then the alkali metal is dissolved.

The recovery equipment of the invention includes a stirring tank, a solid-liquid separation tank and a hydrothermal reaction tank.

The stirring tank includes a stirring tank body, a stirring motor is arranged on the upper part, and a stirring rod is connected with the transmission, and the lower end of the stirring rod is provided with a stirring blade. The top of the stirring tank is also provided with an alkali metal input pipe, a solvent input pipe, an inert gas input pipe, an evacuation pipe and a solid material isolation tank. The working process is:

1. The discharge valve of the solid material isolation tank is closed, and the air in the stirring tank is first pumped out, and then filled with inert gas.

2 Put the alkali metal from the alkali metal input pipe, and put the solvent from the solvent input pipe;

3 When the alkali metal and the solvent are fully reacted, put the pretreated solid waste into the solid material isolation tank, close the feed valve, evacuate the isolation tank, and then fill with inert gas, vacuum again, and then fill with inert gas Gas, operate twice.

4 Open the discharge valve, pour the solid waste into the stirring tank, turn on the stirring motor, and stir and mix.

5 After the solid waste and the alkali metal solution are fully reacted, they are pumped into the mixture output valve, and the solid-liquid mixture flows to the solid-liquid separation tank.

6 After the centrifugal action of the solid-liquid separation tank, the solution flows out from the drain pipe to the hydrothermal reaction tank, and the solid is discharged to the solid secondary recovery tank from the solid discharge pipe set at the inner conical bottom of the separation barrel. [The solid-liquid separation tank includes a tank body and a centrifugal bucket located in the tank body. The top of the centrifugal bucket is connected with the output shaft of the centrifugal motor through spokes (more than three), and the lower end of the centrifugal bucket is provided with a solid discharge pipe. The outer periphery of the solid discharge pipe Sealed rotary connection with the tank body through bearings; the lower end of the solid discharge pipe is provided with a discharge port that deviates to one side, and the center is provided with an ejector rod. The upper part of the ejector rod is provided with an outer cone baffle, During solid-liquid separation, it plays the role of blocking the falling of solids, and plays a guiding role when solids are discharged. There is a discharge cylinder under the ejector rod. When the discharge cylinder rises, the outer conical baffle is raised through the ejector rod, and the solid is discharged to the solid from the gap between the outer conical baffle and the inner cone surface of the centrifugal bucket. Tube discharge. The top of the tank is also provided with a cleaning agent input pipe to inject water or alcohol for cleaning. 】

7 After the separation, the solution is carried out in a hydrothermal reaction tank to crystallize cobalt hydroxide powder crystals, and finally, under the action of gravity, the remaining solution can flow to the solution recovery box) to the metal powder recovery box.

Because the structure of the current hydrothermal reaction tank is not common, the hydrothermal reaction kettle used in the laboratory is more commonly used. In industrial production, considering that the time of hydrothermal reaction is longer than that of stirring reaction and solid-liquid separation, and there are temperature and pressure requirements for hydrothermal reaction, the tank body is not suitable for making it too large. Therefore, a turntable structure (or a rotary transfer belt structure) can be further adopted. With this structure, a plurality of hydrothermal reaction tanks can be installed, and the solution after solid-liquid separation is received in turn, and the hydrothermal reaction is carried out in turn, which can greatly improve the production. efficient.

The specific structure is shown in FIGS. 2 to 7 , a cobalt metal recovery device for lithium ion battery waste according to the present invention includes a stirring tank R, a solid-liquid separation tank S, and a hydrothermal reaction tank T connected by pipelines in sequence. The tanks are connected by valves and pipes.

The solid-liquid separation tank S includes a separation tank body 10, a centrifugal bucket 20 arranged in the separation tank body 10, and the upper part of the centrifugal bucket 20 is connected with the output shaft 221 of the centrifugal motor 22 through the spokes 21 provided. There is a solid discharge pipe 29, and the outer circumference of the solid discharge pipe 29 is connected with the separation tank body 10 through a bearing 291 in a sealed rotation; Rod 28, the top of the ejector rod 28 is provided with an outer conical baffle 281, and the outer conical baffle 281 is in sealing contact with the inner conical surface 200 of the centrifugal bucket 20 during solid-liquid separation to prevent the solid from falling; the ejector rod A discharge cylinder 282 is provided below the 28 . After the solid-liquid separation is completed, the discharge cylinder 282 is lifted, and the outer conical baffle 281 is lifted by the ejector rod 28, and the solid material flows from the gap between the outer conical baffle 281 and the inner cone surface 200 of the centrifugal bucket 20 to the outer cone. The solid discharge pipe 29 is discharged. The feed pipe 24 provided above the separation tank 10 is located within the range of the barrel wall of the centrifuge barrel 20, and the mixture flowing down flows directly into the centrifuge barrel.

The top of the tank is also provided with a cleaning agent input pipe (not shown in the figure) to inject water or alcohol for cleaning; the lower end of the centrifugal bucket 20 is provided with a conical baffle 201 for blocking the solution from entering the bearing; the discharge port Below 299, a solids recovery box 292 is provided. The centrifuge barrel 20 is provided with fine holes on the barrel wall and the inner cone surface, which are used to separate the solution from the solid surface to the inner wall of the tank body and flow to the solution discharge pipe 27 during the rotation and centrifugation.

The stirring tank R includes a stirring tank body 30 , a stirring motor 31 is arranged above the stirring tank body 30 , and a stirring rod 32 is connected to the stirring motor 31 for downward transmission. The lower end of the stirring rod 32 is provided with a stirring blade 33 ; There are also an alkali metal input pipe 301 , a solvent input pipe 302 , a first inert gas input pipe 303 , a first evacuating pipe 304 and a solid material isolation tank 40 . The solid material isolation tank 40 includes an isolation tank 41, a discharge valve 42 located below the isolation tank 41, and a feed valve 43 located above the isolation tank 41 (a hopper 430 is also provided above, which is convenient for pouring the lithium-ion battery waste), the second inert gas input pipe 44 and the second evacuated pipe 45. The stirring tank 30 preferably has a conical bottom, which is convenient for stirring, and a blanking valve 49 is provided at the bottom. The agitated mixture flows from the blanking valve 49 to the solid-liquid separation tank S.

The hydrothermal reaction tank T includes a hydrothermal tank body 50, a liquid inlet valve 51 disposed above the hydrothermal tank body 50, and a crystallization discharge valve 52 disposed below the hydrothermal tank body 50; the crystallization discharge valve 52 is also connected with a crystallization valve. Recovery pipe 53 ; a filter screen 530 is arranged on the lower side of the crystallization recovery pipe 53 to filter the residual solution after the hydrothermal reaction to the solution recovery box 54 . The crystallized cobalt hydroxide powder passes through the crystal recovery pipe 53 and is collected into the crystal recovery box 55 .

When multiple hydrothermal reaction tanks are used (the crystallization recovery tank and the solution recovery tank are also increased correspondingly), it also includes a frame 60 , a turntable 70 arranged above the frame 60 , and a drive mechanism 61 for driving the turntable 70 . (motor, reducer and belt, etc.), the hydrothermal reaction tank T is evenly installed on the said turntable 70 through the bracket 59 .

Since the solution discharge pipe 27 needs to be docked with the liquid inlet valve 51 in sequence, in order to reduce the contact with the air, a liquid discharge docking cylinder 25 (as shown in FIG. 4 ) can be added to drive a transition sleeve sleeved on the outer periphery of the solution discharge pipe 27 Elevator tube 251 . When the turntable 70 needs to be rotated, the liquid discharge docking cylinder rises, which drives the transition lift pipe to rise and leave the inlet of the liquid inlet valve. After the turntable has finished turning, stop. The liquid discharge docking cylinder descends, which drives the transition lift pipe to descend, and is inserted into the inlet of the new liquid inlet valve to transport the solution containing the cobalt-organic intermediate.

For the hydrothermal reaction tank, a heating device can be added to the hydrothermal tank body due to the needs of the recovery method, or the turntable and a plurality of hydrothermal reaction tanks can be installed in a larger oven. Because there is a liquid-draining and docking cylinder, all the hydrothermal reaction tanks can be isolated in the oven when the liquid is not docked and drained to complete the hydrothermal reaction at a constant temperature.

The solution in the solution recovery tank 54 can also be processed (eg, steps such as distillation and water removal), and then mixed in the first step again and reused. Reduce raw material costs.

The above-mentioned valves are preferably electronically controlled to facilitate automatic control. When recycling production, you can stay away from these recycling equipment.

The stirring tank, solid-liquid separation tank, and hydrothermal reaction tank in the above-mentioned embodiments can also be used alone. They are described as follows.

The invention also discloses a solid-liquid separation tank, which comprises a separation tank body, a centrifugal barrel arranged in the separation tank body, the upper part of the centrifugal barrel is connected with the output shaft of the centrifugal motor through the spokes provided, and the centrifugal barrel is connected with the output shaft of the centrifugal motor. The lower end of the solid discharge pipe is provided with a solid discharge pipe, and the outer circumference of the solid discharge pipe is sealed and rotated with the tank body through a bearing; The top of the ejector rod is provided with an outer conical baffle, and the outer conical baffle is kept in sealing contact with the inner conical surface of the centrifuge bucket during solid-liquid separation to prevent the solid from falling; There is a discharge cylinder below. When the discharge cylinder rises, the outer conical baffle is raised by the ejector rod, and the solid material flows from the gap between the outer conical baffle and the inner cone of the centrifugal bucket to the solid discharge pipe. discharge. For the specific implementation structure, reference may be made to the above-mentioned embodiments. Such a solid-liquid separation tank can be used where solid-liquid separation is required, and is not limited to the recycling of lithium electronics.

The invention also discloses a stirring tank, which comprises a stirring tank body, a stirring motor is arranged above the stirring tank body, a stirring rod is connected to the downward driving of the stirring motor, and a stirring blade is arranged at the lower end of the stirring rod The top of the stirring tank is also provided with an alkali metal input pipe, a solvent input pipe, a first inert gas input pipe, a first evacuating pipe and a solid material isolation tank; the solid material isolation tank includes an isolation tank, which is provided with The discharge valve under the isolation tank body, and the feed valve, the second inert gas input pipe and the second vacuum pipe are located above the isolation tank body. For the specific implementation structure, reference may be made to the above-mentioned embodiments. Such a stirred tank is suitable for applications where a sealed reaction is required and a protective gas needs to be filled, and it is not limited to the recycling of lithium electronic waste.

The invention also discloses a hydrothermal reaction tank, which comprises a hydrothermal tank body, a liquid inlet valve disposed above the hydrothermal tank body, and a crystallization discharge valve disposed below the hydrothermal tank body; the crystallization discharge valve A crystal recovery pipe is also connected; a filter screen is arranged on the lower side of the crystal recovery pipe to filter the residual solution after the hydrothermal reaction to a solution recovery box. For the specific implementation structure, reference may be made to the above-mentioned embodiments. Such a hydrothermal reaction tank can be used for industrialized mass production of hydrothermal reactions, and is not limited to the recycling of lithium electronics.

In summary, in a closed system, the cobalt element is extracted by reacting an alkali metal solution with a solid mixture of electrode materials, binders and conductive carbon materials. The reaction conditions are mild and the waste is not discharged to the external environment. It can also be recycled and reused, the reaction is fast, the cost is low, and there is no need to consume additional energy such as electric energy, which is a simple and energy-saving method for effectively recovering cobalt elements in lithium batteries. The recovery equipment of the invention is used to recover the cobalt metal of the lithium ion battery waste material, which can be recovered industrially in large quantities.

The above only uses examples to further illustrate the technical content of the present invention, so that readers can understand it more easily, but it does not mean that the embodiments of the present invention are limited to this. Any technical extension or re-creation made according to the present invention is subject to the protection of. The protection scope of the present invention is subject to the claims.

Claims

A method for recovering cobalt metal from lithium ion battery waste is characterized by comprising the following steps:

Step 1, the solid waste is mixed with the alkali metal solution, fully reacted, and chelated to form a cobalt-organic intermediate;

Step 2, carrying out solid-liquid separation on the solution containing the cobalt-organic intermediate and the solid mixture;

Step 3, hydrothermally react the solution containing the cobalt-organic intermediate to crystallize cobalt hydroxide powder;

Wherein, the solid waste described in step 1 is the waste material containing cobalt element in the lithium ion battery. When mixed with the alkali metal solution, the pretreatment of pulverization and drying is carried out; during the solid-liquid separation in step 2, the surface of the solid object is Wash with water and/or alcohol.
A method for recovering cobalt metal from lithium ion battery waste according to claim 1, characterized in that the first step further comprises the step of making an alkali metal solution, under the protection of an inert gas, completely dissolving the alkali metal in In a solvent, an alkali metal solution is obtained, wherein the concentration of the alkali metal solution is greater than 10-5 mol/L, and the solvent is an organic solvent or liquid ammonia; the alkali metal is lithium, sodium, potassium, rubidium, cesium , at least one of francium, beryllium, magnesium, calcium, strontium and barium; the molar ratio of alkali metal to solvent is 1:0.0001-10.
A kind of cobalt metal recovery method of lithium ion battery waste according to claim 2, it is characterized in that described organic solvent is methylamine, ethylamine, ethylenediamine, propylamine, propylenediamine, butylamine, butanediamine and at least one of polyvalent organic amines.
The method for recovering cobalt metal from lithium ion battery waste according to claim 3, wherein the fully reacted solution in the first step is a free electron solution without protons.
The method for recovering cobalt metal from lithium ion battery waste according to any one of claims 1 to 4, wherein the solid waste is electrode material, binder and conductive carbon material.
A cobalt metal recovery equipment for lithium ion battery waste is characterized by comprising a stirring tank, a solid-liquid separation tank and a hydrothermal reaction tank connected by pipelines in sequence; the solid-liquid separation tank includes a separation tank body, which is arranged in the separation tank body The upper part of the centrifugal bucket is connected with the output shaft of the centrifugal motor through the spokes provided, and the lower end of the centrifugal bucket is provided with a solid discharge pipe, and the outer circumference of the solid discharge pipe is sealed with the tank body through a bearing The lower end of the solid discharge pipe is provided with a discharge port that deviates to one side, and the center is provided with an ejector rod. The upper part of the ejector rod is provided with an outer conical baffle. When the liquid is separated, it is in sealing contact with the inner cone surface of the centrifugal bucket to prevent the solid from falling; a discharge cylinder is arranged below the ejector rod. When the discharge cylinder is raised, the outer cone is blocked by the ejector rod. The plate rises, and the solid material is discharged from the gap between the outer cone baffle and the inner cone surface of the centrifugal bucket to the solid discharge pipe.
The cobalt metal recovery equipment for lithium-ion battery waste according to claim 6, wherein a cleaning agent input pipe is further provided above the tank body to inject water or alcohol for cleaning; the centrifugal bucket The lower end is provided with a conical baffle plate for blocking the solution from entering the bearing; a solid recovery box is provided below the outlet.
The cobalt metal recovery equipment for lithium ion battery waste according to claim 7, wherein the stirring tank comprises a stirring tank body, and a stirring motor is arranged above the stirring tank body, and the stirring motor is directed toward the stirring tank. The lower transmission is connected with a stirring rod, and the lower end of the stirring rod is provided with a stirring blade; the top of the stirring tank is also provided with an alkali metal input pipe, a solvent input pipe, a first inert gas input pipe, a first vacuum pipe and a solid Material isolation tank; the solid material isolation tank includes an isolation tank body, a discharge valve located below the isolation tank body, a feed valve, a second inert gas input pipe and a second vacuum pipe located above the isolation tank body .
The cobalt metal recovery equipment for lithium ion battery waste according to claim 8, wherein the hydrothermal reaction tank comprises a hydrothermal tank body, and a liquid inlet valve disposed above the hydrothermal tank body is located in the The crystallization discharge valve under the hydrothermal tank body; the crystallization discharge valve is also connected with a crystallization recovery pipe; the lower side of the crystallization recovery pipe is provided with a filter screen to filter the residual solution after the hydrothermal reaction to the solution recovery tank .
The cobalt metal recovery equipment for lithium-ion battery waste according to claim 9, wherein the hydrothermal reaction tank has at least two or more, and further comprises a rack, a turntable arranged above the rack, and a For the drive mechanism for driving the turntable, the hydrothermal reaction tank is evenly installed on the turntable.