TWI644468B - Method for recycling cobalt in waste lithium battery - Google Patents

Abstract

A method for recovering cobalt in a waste lithium battery, comprising the steps of: (A) providing a waste lithium battery positive electrode material powder; (B) adding the lithium battery positive electrode material powder to a first acid liquid, and placing it in a microwave system or a Extracting in an ultrasonic system to form a cobalt-containing solution; (C) adding the cobalt-containing solution to a potassium permanganate solution to remove manganese in the cobalt-containing solution to obtain a de-manganese-containing cobalt solution; (D) Adding the manganese removal cobalt-containing solution to an extractant to extract an organic phase cobalt-containing extract; and (E) adding the cobalt-containing extract to a second acid solution for reverse phase extraction to make cobalt and The organic phase is separated in a cobalt-containing extract, thereby obtaining a water-containing cobalt solution.

Description

Method for recovering cobalt from waste lithium battery

The present invention relates to a method for recovering cobalt from a waste lithium battery, and more particularly to a method for recovering cobalt by extracting a waste lithium battery in a microwave system or an ultrasonic system.

With the advancement of technology, the market for mobile device products and electric vehicles has grown rapidly. Lithium batteries should have the advantages of light weight, high energy density, high operating voltage, and no memory effect. Therefore, they are widely used in notebook computers, communication and consumer electronic products, and have also developed into electric vehicles in recent years. Lithium batteries have also replaced nickel-hydrogen, nickel-cadmium, and lead-acid batteries as the main power source because of their relative environmental protection, stable discharge, and long cycle life. However, they also generate huge amounts of electronic waste. How to recycle and manage lithium batteries Electronic waste is a major issue. The existing traditional immersion dissolution technology utilizes various acid liquids as an immersion liquid, and puts the treated waste lithium battery into the immersion liquid at room temperature or at a specified temperature, and appropriately uses the cobalt to be recovered in the solid phase metal compound. The solvent is dissolved in an ionic state and stored in the impregnation solution. The heating method used in the conventional impregnation is slow, and the reaction time required for the impregnation process is long. It takes a considerable amount of energy to maintain the temperature for a long time.

According to statistics, the global lithium battery industry is growing at a rate of about 12-15% per year. The annual production and usage of secondary lithium batteries are increasing year by year. It is estimated that the output in 2015 will exceed 3 billion. In 2011, the Japan Institute of Technology Systems proposed that the global market demand for secondary lithium batteries will reach 3.9 billion in 2010; it is estimated that the global demand for secondary lithium batteries in 2016 will reach more than 7 billion (excluding electric Car and the Chinese market). This number of lithium batteries allows them to recycle and deal with the business opportunity that comes with it. Benefits can be seen. If it can be properly recycled, it can increase the resource reuse rate in addition to reducing environmental impact. Cobalt is a naturally occurring element found in rocks, soil, water, plants and animals. Cobalt is used in the production of alloys for the manufacture of aircraft engines, magnets, grinding, cutting tools, artificial hip joints and knee joints. Cobalt compounds are also used in stained glass, ceramics and paints, and as a desiccant for porcelain enamels and paints. In recent years, in the case of high oil prices, nuclear power generation has become a power development strategy for various countries, making the price of cobalt also high. Because cobalt is a strategic metal, the global reserves are less than 10 million tons, and the annual output is only about 40,000 tons. The quantity is limited. Therefore, cobalt (Co) is the most critical cost material affecting battery performance, which limits the cost of lithium cobalt batteries.

For example, referring to FIG. 1, the invention patent of the Republic of China Publication No. I535479 discloses a method for recovering valuable metals, wherein step S1 uses a discharge program and a pulverization sorting process to remove the outer casing of the waste secondary lithium battery. A powder of a positive electrode material containing one of cobalt, manganese, nickel, aluminum and lithium is obtained. Step S2 uses an alkali dissolution procedure to precipitate to remove aluminum metal in the powder. In step S3, the powder is impregnated with an acid immersion liquid containing manganese, cobalt, nickel and lithium by using an acid solution containing hydrogen peroxide and sulfuric acid. Step S4 extracts manganese, cobalt, nickel and lithium from the acid immersion liquid by using an extracting agent to respectively form a first oil phase solution containing manganese and a first aqueous phase raffinate containing one of cobalt, nickel and lithium. In step S5, the first aqueous phase raffinate is subjected to solvent extraction to respectively form a second oil phase solution containing cobalt and a second aqueous phase raffinate containing nickel and lithium. Step S6 uses a recovery procedure to recover manganese, cobalt, nickel, and lithium from the stripping solution of the first oil phase solution, the stripping solution of the second oil phase solution, and the second aqueous phase raffinate, respectively, wherein the recovery procedure may include A chemical precipitation reaction or an electrolytic reaction which precipitates metal ions by a redox reaction, and the electrolytic reaction reduces metal ions to metal elements. However, in the above method, after the aluminum foil is first broken, the aluminum is dissolved and removed by using an alkaline solution, so that the operation step is increased to cause a long operation time. And the immersion time is long, resulting in energy consumption and high recycling cost.

However, the above-mentioned conventional method for recovering valuable metals from the waste lithium battery still has the following problems in practical use, for example, after the aluminum foil is crushed, the aluminum is dissolved and removed by using an alkaline solution, so that the operation step is long and the operation time is long. . again The acid immersion time is long, resulting in energy consumption and high recycling costs.

Therefore, it is necessary to provide a method for recovering cobalt from a waste lithium battery to solve the problems of the conventional technology. In particular, the extraction time is long and the cost is high.

The main object of the present invention is to provide a method for recovering cobalt from a waste lithium battery by using a simplified lithium battery recovery process step to provide a rapid dissolution mode, thereby improving the efficiency of precious metal recovery in a lithium battery.

A secondary object of the present invention is to provide a method for recovering cobalt from a waste lithium battery by extracting in a microwave system or an ultrasonic system to reduce the time required for processing the leaching and elution, thereby improving the efficiency of recovering cobalt from the waste lithium battery. .

In order to achieve the above object, the present invention provides a method for recovering cobalt from a waste lithium battery, comprising the steps of: (A) providing a waste lithium battery positive electrode material powder; (B) adding the lithium battery positive electrode material powder to a first acid liquid. And being extracted in a microwave system or an ultrasonic system to form a cobalt-containing solution; (C) adding the cobalt-containing solution to a potassium permanganate solution to remove manganese in the cobalt-containing solution, thereby obtaining a go a manganese-containing cobalt solution; (D) adding the de-manganese-containing cobalt solution to an extractant to extract an organic phase cobalt-containing extract; and (E) adding the cobalt-containing extract to a second acid solution for inversion Extraction is carried out to separate the cobalt and the cobalt-containing extract from the organic phase, thereby obtaining a water-containing cobalt solution.

In an embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the step (A) further comprises a pretreatment step comprising the steps of: (i) providing a waste lithium battery (ii) disassembling the waste lithium battery to take out a positive electrode portion of the waste lithium battery; (iii) immersing the positive electrode portion in a N-methylpyrrolidone solution to detach a positive electrode material and separate the waste lithium battery One of the aluminum foils in the pool; (iv) calcining the positive electrode material in a calciner to remove impurities in the positive electrode material to obtain a calcined positive electrode material; (v) crushing the calcined positive electrode material to obtain The waste lithium battery cathode material powder.

In one embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the N-methylpyrrolidone is immersed at a temperature of 80 ° C to 100 ° C, and the immersion time is 40 to 60 minutes; and the positive electrode material is The calcination temperature of the calciner is The calcination time is from 1 to 3 hours from 500 ° C to 700 ° C.

In an embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, further comprising a step before the step (iii): crushing the positive electrode portion into a powder by a grinder, and The 60-mesh screen was used to screen the positive portion powder to obtain a positive electrode portion powder having a particle size range of less than 60 mesh.

In an embodiment of the invention, the method for recovering cobalt in the waste lithium battery, wherein the first acid solution is sulfuric acid, citric acid or succinic acid.

In an embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the step (B) further comprises adding a reducing agent, the reducing agent is added in a proportion of 1% to 4% by volume. .

In one embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the lithium battery positive electrode material powder is added to the first acid liquid and then placed in the microwave system for extraction at a reaction temperature of 40 ° C to The extraction time is 5 to 40 minutes at 100 ° C, the solid-liquid ratio is 15 g / liter to 30 g / liter, and the molar concentration of the first acid solution is 1 M to 3 M.

In one embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the reaction time of the step (C) is 40 minutes to 60 minutes, and the reaction acid value is 2 to 4.

In one embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the extracting agent in the step (D) is di(2-ethylhexyl)phosphoric acid, and the extraction reaction time is 15 minutes. By 75 minutes, the reaction has a pH of 2 to 6, the ratio of the organic phase to the aqueous phase is 1 to 3, and the molar concentration of the extractant is 0.05 M to 1 M.

In one embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the second acid solution of the step (E) is hydrochloric acid, and the molar concentration of the second acid liquid is 4M to 6M. And the reaction time is from 10 minutes to 60 minutes.

In an embodiment of the present invention, the method for recovering cobalt in the waste lithium battery, wherein the step (E) further comprises a step (F), and an electrolysis process is performed on the aqueous phase cobalt-containing solution to recover cobalt. The electrolysis program is operated under conditions of a current of 0.5 A to 0.9 A, a voltage of 3 V to 5 V, and an electrolysis time of 7 hours to 10 hours.

S1~S6‧‧‧Steps

21~25‧‧‧Steps

31~36‧‧‧Steps

Fig. 1 is a block diagram showing the flow of a method for recovering cobalt from a waste lithium battery of the prior art.

Fig. 2 is a block diagram showing a pretreatment flow of a method for recovering cobalt in a spent lithium battery of the first embodiment of the present invention.

Fig. 3 is a block diagram showing the flow of a method for recovering cobalt in a spent lithium battery according to a first embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; Furthermore, the directional terms mentioned in the present invention, such as upper, lower, top, bottom, front, rear, left, right, inner, outer, side, surrounding, central, horizontal, horizontal, vertical, longitudinal, axial, Radial, uppermost or lowermost, etc., only refer to the direction of the additional schema. Therefore, the directional terminology used is for the purpose of illustration and understanding of the invention.

Referring to Figures 2 and 3, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention mainly comprises the steps of: providing a waste lithium battery positive electrode material powder; adding the lithium battery positive electrode material powder to a first acid And extracting in a microwave system or an ultrasonic system to form a cobalt-containing solution; adding the cobalt-containing solution to a potassium permanganate solution to remove manganese in the cobalt-containing solution to obtain a de-manganese-containing solution a cobalt solution; adding the demineralized cobalt-containing solution to an extractant to extract an organic phase cobalt-containing extract; and adding the cobalt-containing extract to a second acid solution for reverse phase extraction to make cobalt and The organic phase is separated in a cobalt-containing extract, thereby obtaining a water-containing cobalt solution. Thereafter, electrolysis may be performed from the aqueous phase cobalt-containing solution to recover cobalt. Optionally, before the step of providing the waste lithium battery positive electrode material powder, the pretreatment step further comprises the steps of: providing a waste lithium battery; disassembling the waste lithium battery to take out the waste lithium battery a positive electrode portion in the pool; the positive electrode portion is immersed in the N-methylpyrrolidone solution to detach a positive electrode material and separate one of the aluminum foils in the waste lithium battery; and the positive electrode material is calcined in a calciner Removing impurities in the positive electrode material to obtain a calcined positive electrode material; breaking the calcined positive electrode material The powder of the positive electrode material of the waste lithium battery is obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIGS. 2 and 3 in conjunction with the description of the specification.

Referring to FIG. 2, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is firstly to provide a waste lithium battery. In step 21 shown in Fig. 2, the waste lithium battery is formed by a waste lithium battery. Alternatively, the waste lithium battery may be a waste lithium battery of other sources, such as a waste lithium battery for an electric vehicle, a waste lithium battery for an electric bicycle, or a waste lithium battery for any rechargeable electric appliance. In the first embodiment of the present invention, a lithium cobalt oxide or lithium nickel manganese cobalt oxide battery using a recycled waste mobile phone is used. Then, the waste lithium battery may still have some micro-electricity remaining, so the battery must be completely discharged to ensure safety before disassembling the battery. Optionally, in this embodiment, a wet discharge method may be employed, which is immersed in a sodium chloride solution to discharge.

Referring to FIG. 2, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by disassembling the waste lithium battery to take out a positive electrode portion of the waste lithium battery. In step 22 shown in Fig. 2, the plastic and steel of the battery are manually removed. Generally, the waste lithium battery contains a positive electrode, a negative electrode and a separator, and most of the valuable metals are present in the positive electrode material (LiCoO ₂ ) of the lithium battery. It needs to be disassembled first to obtain the positive electrode material.

Referring to FIG. 2, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by immersing the positive electrode portion in a solution of N-methylpyrrolidone to detach a positive electrode material and separate the waste lithium battery. One of the aluminum foil in the pool. In step 23 shown in Fig. 2, the positive electrode portion is immersed in a N-methylpyrrolidone solution to detach a positive electrode material. In order to avoid the subsequent extraction process, the aluminum is additionally treated. After the NMP solution is immersed, one of the aluminum foils of the waste lithium battery is separated and stripped, so that the aluminum foil is taken out before being broken to reduce the complexity of subsequent processing. Preferably, the N-methylpyrrolidone is impregnated at a temperature of from 80 ° C to 100 ° C and the immersion time is from 40 to 60 minutes. Next, optionally, the aluminum foil-removed positive electrode material is subjected to a drying treatment. The drying treatment may be naturally air-dried or oven-dried.

Next, referring to FIG. 2, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by calcining the positive electrode material in a calciner to remove impurities in the positive electrode material. As shown in step 24 shown in Fig. 2, the positive electrode material is calcined in a calciner to remove impurities in the positive electrode material to obtain a calcined positive electrode material. The impurity can be carbon, Polyvinylidene fluoride and binders. Preferably, the calcining temperature of the positive electrode material in the calciner is from 500 ° C to 700 ° C, and the calcination time is from 1 to 3 hours. In the present embodiment, the positive electrode material was placed in a calciner and calcined at 700 ° C for 3 hours.

Next, referring to FIG. 2, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by crushing the calcined positive electrode material to obtain the waste lithium battery positive electrode material powder. As shown in step 25 shown in Fig. 2, the calcined positive electrode material is crushed using a grinder (for example, a ball mill) to reduce the particle size to form the waste lithium battery positive electrode material powder. In the present embodiment, in order to promote the dissolution efficiency, the positive electrode portion is crushed into a powder by an attritor, and the positive electrode portion powder is screened by a 60 mesh screen to obtain a particle size range of less than 60 mesh. A positive partial powder. In this way, both the dissolution efficiency and the waste time can be avoided.

Referring to FIG. 3, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by providing a waste lithium battery positive electrode material powder. As shown in step 31 of Fig. 3, the waste lithium battery positive electrode material powder pretreated by the above steps is weighed to a certain weight to provide the operation of the subsequent steps.

Referring to FIG. 3, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by adding the lithium battery positive electrode material powder to a first acid solution and placing it in a microwave system or an ultrasonic system. Extraction to form a cobalt-containing solution. The lithium battery positive electrode material powder is added to a first acid solution as shown in step 32 shown in FIG. Preferably, the first acid solution is citric acid, succinic acid and sulfuric acid. Preferably, the lithium battery positive electrode material powder further contains a reducing agent (for example, hydrogen peroxide). Preferably, the reducing agent is added in an amount of from 1% to 4% by volume. After the lithium battery positive electrode material powder is added to the first acid solution, it is placed in a microwave system or an ultrasonic system for extraction. Preferably, the reaction temperature of the extraction in the microwave system is 40 ° C to 100 ° C, the extraction time is 5 to 40 minutes, the solid-liquid ratio is 15 g / liter to 30 g / liter, and the molar concentration of the first acid solution It is 1M to 3M. After the extraction, the metal in the lithium battery positive electrode powder is dissolved in the first acid solution to form a cobalt-containing solution. The first acid solution after extraction further contains other metals (for example, manganese or lithium, etc.). Preferably, the extracted first acid solution is subjected to a separation step (for example, filtration or centrifugation, etc.) to remove the solid matter in the extracted first acid solution to obtain a clear liquid.

Next, referring to FIG. 3, the lithium battery of the first embodiment of the present invention is returned. The method of collecting cobalt is followed by adding the cobalt-containing solution to a potassium permanganate solution to remove manganese in the cobalt-containing solution to obtain a de-manganese-containing cobalt solution. As shown in step 33 of Figure 3, the cobalt-containing solution is added to a potassium permanganate solution. Preferably, the potassium permanganate solution has a molar concentration of 0.5M. After the cobalt-containing solution is added to the potassium permanganate solution, manganese ions originally in the cobalt-containing solution are precipitated. The cobalt-containing solution added to the potassium permanganate solution is then subjected to a separation step (for example, filtration or centrifugation, etc.) to remove manganese to obtain a de-manganese-containing cobalt solution. Preferably, the cobalt-containing solution is added to the potassium permanganate solution for a reaction time of 40 minutes to 60 minutes, and the reaction pH is adjusted to 2 to 4.

Referring to FIG. 3, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by adding the demagnetized cobalt-containing solution to an extractant to extract an organic phase cobalt-containing extract. As shown in step 34 of Figure 3, the extractant is di(2-ethylhexyl)phosphoric acid (D2EHPA). During extraction, D2EHPA releases hydrogen ions on the -OH group and exchanges with the extracted cations. As a result, the metal cations enter the organic phase (for ease of writing, the structure is simply expressed by HA), and the chemical reaction formula of the extraction is as follows :Co ²⁺ (aqueous phase) + 2HA (organic phase) = CoA ₂ (organic phase) + 2H ⁺

Preferably, in this embodiment, the reaction time of adding the de-manganese-containing cobalt solution to the extracting agent for extraction is 15 minutes to 75 minutes, the reaction acid-base value is 2 to 6, and the ratio of the organic phase to the aqueous phase is 1 to 3. And the molar concentration of the extractant is 0.05M to 1M.

Referring to FIG. 3, the method for recovering cobalt from the waste lithium battery of the first embodiment of the present invention is followed by: adding the cobalt-containing extract to a second acid solution for reverse phase extraction to make cobalt and the organic phase. The cobalt-containing extract is separated, thereby obtaining a water-containing cobalt solution. As shown in step 35 shown in Figure 3, preferably, the cobalt-containing extract is added to monohydrochloric acid for reverse phase extraction. The metal salt formed by the combination with the metal reacts with the strong acid, the metal salt of D2EHPA is hydrolyzed, D2EHPA exists in the form of free acid, and the metal ion enters the water phase, thereby achieving stripping.

Preferably, the molar concentration of the second acid solution in the embodiment is 4M to 6M, and the reaction time is 10 minutes to 60 minutes.

Referring to FIG. 3, the waste lithium battery of the first embodiment of the present invention recovers cobalt. Finally, the method comprises: electrolyzing the aqueous phase cobalt-containing solution to recover cobalt. As shown in step 36 shown in Fig. 3, the cobalt-containing solution entering the aqueous phase is subjected to an electrolysis procedure to recover cobalt to recover cobalt. Preferably, the electrolysis procedure is operated at a current of from 0.5 A to 0.9 A, a voltage of from 3 V to 5 V, and an electrolysis time of from 7 hours to 10 hours.

By the above steps, the first embodiment of the present invention can be extracted in the microwave system or the ultrasonic system, particularly under the above preferred operating conditions, to increase the extraction efficiency. Since the extraction efficiency is improved in the microwave system or the ultrasonic system, it is advantageous to further shorten the required extraction time. At the same time, the extraction rate can also be increased, thereby reducing the recovery cost of cobalt in the waste lithium battery.

The method for recovering cobalt from the spent lithium battery of the second embodiment of the present invention is similar to the first embodiment of the present invention, and is only compared with the difference in conventional impregnation extraction efficiency under acid extraction using a microwave system or an ultrasonic system. As shown in Table 1 below.

Table 1 shows the dissolution efficiency for cobalt using different methods, wherein Group I is using conventional impregnation (heating only, no microwave or ultrasonic waves) under the condition of using 2 M sulfuric acid with a molar concentration of 2 M. The agent was immersed for 60 minutes under the conditions of a solid-liquid ratio of 20 g/liter and a temperature of 80 °C. Group II was subjected to microwave extraction under the conditions of using a sulfuric acid having a molar concentration of 2 M and adding 2 vol% of a reducing agent, and immersing for 5 minutes under the conditions of a solid-liquid cobalt dissolution efficiency ratio of 25 g/liter and a temperature of 80 °C. Group III was subjected to ultrasonic extraction under the conditions of using a sulfuric acid having a molar concentration of 2 M and adding 2 vol% of a reducing agent, and immersing for 60 minutes at a solid-liquid ratio of 20 g/liter and a temperature of 60 °C. From the cobalt dissolution efficiency, the use of microwave extraction is the best for cobalt dissolution, The extraction time can be greatly shortened, and the solid-liquid ratio at the time of extraction can be raised to 25 g/liter.

Compared to the first embodiment, the second embodiment further shows that microwave extraction is preferred to conventional impregnation and ultrasonic extraction under the above operating conditions. Thereby, not only the extraction time can be shortened, but also the solid-liquid ratio at the time of extraction can be increased, thereby further increasing the extraction efficiency of cobalt.

The present invention has been disclosed in its preferred embodiments, and is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Claims (8)

A method for recovering cobalt in a waste lithium battery, comprising the steps of: (A) providing a waste lithium battery positive electrode material powder; (B) adding the lithium battery positive electrode material powder to a first acid liquid, and placing it in a microwave system or a Extracting in an ultrasonic system to form a cobalt-containing solution; (C) adding the cobalt-containing solution to a potassium permanganate solution to remove manganese in the cobalt-containing solution to obtain a de-manganese-containing cobalt solution; (D) Adding the manganese removal cobalt-containing solution to an extractant to extract an organic phase cobalt-containing extract; and (E) adding the cobalt-containing extract to a second acid solution for reverse phase extraction to make cobalt and The organic phase is separated from the cobalt-containing extract, thereby obtaining a water-containing cobalt solution, wherein the first acid solution is sulfuric acid, citric acid or succinic acid; and the extracting agent of the step (D) is di(2-ethylhexyl) The phosphoric acid, the extraction reaction time is 15 minutes to 75 minutes, the reaction pH value is 2 to 6, the ratio of the organic phase to the aqueous phase is 1 to 3, and the molar concentration of the extractant is 0.05M to 1M; And the second acid solution of the step (E) is hydrochloric acid, and the molar concentration of the second acid solution is 4M to 6M, and the reaction time From 10 minutes to 60 minutes. The method for recovering cobalt in a waste lithium battery according to claim 1, wherein the step (A) further comprises a pretreatment step comprising: (i) providing a waste lithium battery; Ii) disassembling the waste lithium battery to take out a positive electrode portion of the waste lithium battery; (iii) immersing the positive electrode portion in N-methylpyrene In a solution of a rotary ketone, a positive electrode material is detached and one of the aluminum foils of the waste lithium battery is separated; (iv) the positive electrode material is calcined in a calciner to remove impurities in the positive electrode material to obtain a The calcined cathode material is calcined; (v) the calcined cathode material is crushed to obtain the cathode material powder of the waste lithium battery. A method for recovering cobalt in a waste lithium battery according to claim 2, wherein the N-methylpyrrolidone has an immersion temperature of 80 ° C to 100 ° C and an immersion time of 40 to 60 minutes; and the positive electrode material is forged The calcination temperature of the furnace is from 500 ° C to 700 ° C, and the calcination time is from 1 to 3 hours. The method for recovering cobalt in a waste lithium battery according to claim 2, wherein before the step (iii), the method further comprises the step of: crushing the positive electrode portion into a powder by a grinder, and using 60 mesh The sieve was screened for the positive electrode portion powder to obtain a positive electrode portion powder having a particle size range of less than 60 mesh. The method for recovering cobalt in a waste lithium battery according to claim 1, wherein the step (B) further comprises adding a reducing agent in an amount of from 1% to 4% by volume. The method for recovering cobalt in a waste lithium battery according to claim 1, wherein the lithium battery positive electrode material powder is added to the first acid solution and then placed in the microwave system for extraction at a reaction temperature of 40 ° C to 100 ° C. The extraction time is 5 to 40 minutes, the solid-liquid ratio is 15 g/liter to 30 g/liter, and the first acid solution has a molar concentration of 1 M to 3 M. A method for recovering cobalt in a waste lithium battery according to claim 1, wherein the reaction time of the step (C) is from 40 minutes to 60 minutes, and the reaction pH is from 2 to 4. A method for recovering cobalt in a waste lithium battery according to claim 1 of the patent application, The step (E) further comprises a step (F) of performing an electrolysis procedure on the aqueous phase cobalt-containing solution to recover cobalt. The electrolysis procedure is operated at a current of 0.5 A to 0.9 A and a voltage of 3 V to 8 V. And the electrolysis time is from 7 hours to 10 hours.