TWI535479B - Valuable metals recovering method - Google Patents

Description

Method of recycling valuable metals

The following description relates to a method for recovering valuable metals, and more particularly to a method for recovering and separating and purifying cobalt, manganese, nickel or lithium from a spent lithium battery using hydrogen peroxide and ultrasonic assist.

The secondary battery can be converted into chemical energy by the charging process, and the secondary battery is popularized in the global market due to the environmentally-friendly concept of the rechargeable function. Commercially, secondary lithium batteries are generally classified into lithium cobalt oxide (lithium oxide, LiCoO ₂ ), lithium nickelate (lithium nickel oxide, LiNiO ₂ ), lithium manganate (lithium manganese oxide, LiMn) depending on the cathode material. ₂ O ₄ ), ternary cobalt lithium nickel manganese oxide (lithium oxide cobalt nickel manganese, LiCoO ₂ /LiNiO ₂ /LiMn ₂ O ₄ ), lithium iron phosphate (lithium iron phosphorus, LiFePO ₄ ).

In general, lithium cobalt oxide batteries are mainly used in handheld device electronic products; lithium nickel acid batteries have not been overcome because of safety, so producers and users are less; and lithium manganate batteries are safe because of their high safety. Currently widely used in hand tools. The evaluation results of the positive electrode material of the secondary lithium battery show that the secondary lithium battery with lithium cobaltate as the positive electrode material accounts for about 40% of the cost of the positive electrode material, but the secondary lithium battery with lithium manganate as the positive electrode material has its positive electrode. The cost of the material is about 20%. The use of lithium manganate as the positive electrode material can lower the price of the secondary lithium battery, and the compatibility of the manganese element with the environment is high. Therefore, the ternary system (LiCoO ₂ /LiNiO ₂ /LiMn ₂ O ₄ ) cathode material increases the capacitance by increasing the nickel element and increases the manganese element to meet safety and low cost requirements. Because the ternary cathode material can reduce the cost, its small size and light weight, with room for development and progress, gradually emerged in the market, becoming the most competitive cathode material in secondary lithium batteries, and began to ship in 2012.

However, when the ternary cathode material lithium battery is discarded after two to five years, it will affect the applicability of the current recycling technology in the future. Secondary lithium batteries contain a variety of metal elements (lithium, cobalt, nickel, manganese, copper, aluminum, etc.), which are mostly valuable materials. If they are used in limited resources, if they are not recycled, the resources will be exhausted. Among them, cobalt metal accounts for only 25ppm in nature, and the reserves are quite rare. When lithium batteries are gradually put into use, the source of raw materials is bound to be limited by the amount of production. Therefore, based on the limited resources and increasing usage, the recycling of battery materials will be an important issue for all countries in the future.

The aspect of the embodiment of the present invention is directed to a method for recovering valuable metals, which can improve the purity of valuable metals such as cobalt, manganese, nickel and lithium from waste lithium batteries.

Based on the above object, the present invention provides a method of recovering valuable metals suitable for use in a waste secondary lithium battery. The method of recovering the valuable metal may include the steps of removing the outer casing of the waste secondary lithium battery by a discharge program and a cutting and stripping procedure, followed by a pulverization sorting process to produce a positive electrode material powder containing cobalt, manganese, nickel, aluminum, and lithium. The aluminum metal in the powder is removed by precipitation using an alkali dissolution procedure. The acid immersion liquid is mixed by using an acid liquid containing sulfuric acid but not containing hydrogen peroxide, and the ratio of the acid liquid to the powder is between 1 g/100 ml and 4 g/100 ml, and the acid liquid and the powder system are placed in the super In the sonic amplifier, the concentration of sulfuric acid in the acid solution is between 3N and 4N, and the temperature at which the acid solution and the powder are mixed is between 45 and 55 degrees Celsius, and the above conditions can make the acid immersion liquid contain 1% or less. Manganese. The acid immersion liquid is extracted with manganese, cobalt nickel and lithium by an extracting agent, and pre-extracted to remove trace metals such as copper and iron. The impurity-containing acid immersion liquid is further subjected to solvent extraction to form a first oil phase solution containing manganese and a first aqueous phase raffinate containing cobalt, nickel and lithium, and then extracting the first aqueous phase raffinate to generate a second oil phase solution containing cobalt and a second aqueous phase raffinate containing nickel and lithium. And recovering the purified manganese, cobalt and nickel by using a recovery program to separately extract 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 And lithium, wherein the recovery procedure can comprise a chemical precipitation reaction or an electrolytic reaction.

Preferably, the chemical precipitation reaction utilizes a redox reaction to precipitate metal ions, and the electrolytic reaction reduces metal ions to metal elements.

Preferably, the redox reaction comprises adjusting the pH of the stripping solution of the first oil phase solution or the stripping solution of the second oil phase solution or the second aqueous phase raffinate to make the cobalt , manganese, nickel or lithium is precipitated, and cobalt, manganese, nickel or lithium is recovered by filtration in the form of a solid salt, and the pH ranges from 2.0 to 11.0.

Preferably, the pH adjusting agent comprises sodium hydroxide, sodium carbonate, sodium sulfide, and ammonium oxalate.

Preferably, the method for recovering valuable metals of the present invention further comprises dissolving a solid salt in an acid solution for electrolytically refining cobalt, manganese or nickel.

Preferably, the extractant comprises D2EHPA or Cyanex272.

Preferably, the ultrasonic amplifier for placing acid and powder has a frequency between 20 kHz and 28 kHz.

Based on the above object, the present invention further provides a method for recovering valuable metals, which is suitable for a positive electrode material of a waste secondary lithium battery. The method for recovering valuable metals may include the following steps: forming a positive electrode material by a discharge process and a pulverization sorting process A powder containing manganese, cobalt, nickel, aluminum and lithium. The alkali metal in the powder is removed by precipitation using an alkali dissolution procedure. Mixing powder containing one of sulfuric acid to impregnate an acid impregnation solution containing manganese, cobalt, nickel and lithium, wherein the ratio of acid to powder is between 1g/100ml and 4g/100ml, and the acid solution And the powder system is placed in an ultrasonic device for mixing and 0.25ml to 2.5ml, 35% hydrogen peroxide is added every hour, the concentration of sulfuric acid in the acid solution is between 3N and 4N, the acid solution The temperature when mixed with the powder is between 45 ° C and 55 ° C. The acid immersion liquid is extracted with manganese, cobalt, nickel and lithium by an extracting agent to form a first oil phase solution containing manganese and a first aqueous phase raffinate containing one of cobalt, nickel and lithium. Extracting cobalt in the first aqueous phase raffinate to divide Do not form a second oil phase solution containing cobalt and a second aqueous phase raffinate containing nickel and lithium. And recovering manganese, cobalt, nickel, and lithium by using 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. Contains a chemical precipitation reaction or an electrolytic reaction.

Preferably, the ultrasonic device may comprise an ultrasonic oscillating groove or an ultrasonic wave.

Preferably, the frequency of the ultrasonic oscillation tank is between 28KHz and 200KHz, and the frequency of the ultrasonic amplifier is between 20KHz and 28KHz.

Preferably, the dissolution reaction formula of hydrogen peroxide is 2LiCoO ₂ +3H ₂ SO ₄ +H ₂ O ₂ =Li ₂ SO ₄ +2CoSO ₄ +O ₂ ↑+4H ₂ O _(l)

S1~S6‧‧‧Steps

The above and other features and advantages of the present invention will become more apparent from the detailed description of the exemplary embodiments thereof

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the steps of a method for recovering valuable metals according to an embodiment of the present invention.

Fig. 2A is a first schematic view showing the concentration of acid-soluble extracted metal according to another embodiment of the present invention.

Figure 2B is a second schematic diagram of the acid-extracted metal concentration in accordance with another embodiment of the present invention.

Figure 2C is a third schematic diagram of the acid-extracted metal concentration in accordance with another embodiment of the present invention.

Figure 3A is a first schematic view of solvent extraction and stripping in accordance with a second embodiment of the present invention.

Figure 3B is a second schematic view of solvent extraction and stripping in accordance with a second embodiment of the present invention.

Figure 3C is a third schematic view of solvent extraction and stripping in accordance with a second embodiment of the present invention.

Figure 4 is a schematic illustration of the extraction rate of various metal ions extracted in accordance with the present invention.

Fig. 5A is a schematic diagram showing the metal concentration obtained in the first stripping according to the present invention and the equivalent concentration of the stripping solution.

Figure 5B is a graphical representation of the concentration of metal obtained and the equivalent concentration of the stripping solution in the second stripping according to the present invention.

The features, the contents and advantages of the present invention, and the advantages thereof, will be understood by the present invention. The present invention will be described in detail with reference to the accompanying drawings, The use of the present invention is not intended to be a limitation of the scope of the present invention, and the scope of the present invention is not limited by the scope and configuration of the accompanying drawings.

The advantages and features of the present invention, as well as the technical methods of the present invention, are described in more detail with reference to the exemplary embodiments and the accompanying drawings, and the present invention may be implemented in various forms and should not be construed as limited thereby. The embodiments of the present invention, and the embodiments of the present invention are intended to provide a more complete and complete and complete disclosure of the scope of the present invention, and The scope of the patent application is defined.

Please refer to FIG. 1, which is a first flow chart showing the steps of recovering valuable metals according to an embodiment of the present invention. As shown in Figure 1, this method of recovering valuable metals is applicable to one waste twice. A lithium battery, the method of recovering a valuable metal may include the following steps. Step S1 uses a discharge process and a pulverization sorting process to remove the outer casing of the waste secondary lithium battery to obtain a positive electrode material powder containing cobalt, manganese, nickel, aluminum and lithium. 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 liquid containing hydrogen peroxide and sulfuric acid, wherein the acid liquid and the powder system are placed in an ultrasonic device. 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.

It is worth mentioning that the ratio of powder to acid is in the range of 1g/100ml~4g/100ml, the immersion time ranges from 0.5 to 3.0 hours, the acid solution contains 3.0~4.0N sulfuric acid, and the acid impregnation temperature is between Celsius. 45 degrees to 55 degrees, and 2.5 ml of 35% hydrogen peroxide at intervals.

Wherein, the dissolution reaction formula of hydrogen peroxide in step S3 is 2LiCoO ₂ +3H ₂ SO ₄ +H ₂ O ₂ =Li ₂ SO ₄ +2CoSO ₄ +O ₂ ↑+4H ₂ O _(l) , and the ultrasonic device It includes an ultrasonic oscillating groove or an ultrasonic amplifier. When the acid and powder are placed in the ultrasonic oscillating tank, 0.25~2.5ml of hydrogen peroxide with a concentration of 35% is added at intervals.

Furthermore, the frequency of the ultrasonic oscillation tank is between 28KHz and 200KHz, and the frequency of the ultrasonic amplifier is between 20KHz and 28KHz.

Before carrying out the recovery of valuable metals from waste secondary lithium batteries, it is necessary to go through a pre-treatment process, which mainly includes a discharge program and a stripping/crushing procedure. The former is to avoid the burning or explosion phenomenon in the subsequent processing, and the discharge must be utilized. Program until the battery is fully discharged. The latter mainly cuts The outer casing of the waste secondary lithium battery is removed by a method such as stripping, and the powder of the positive electrode material is pulverized by sorting or scraping to prevent the positive electrode material powder from containing excessive amounts of impurities and impurities. On the one hand, the stripped outer shell can be first subjected to a sorting process for recovering metal fragments or powders, as well as plastic chips or powders, and on the other hand, a subsequent acid dissolution procedure is performed from the positive material powder, wherein the positive electrode material powder Contains manganese, cobalt, nickel, lithium and a small amount of aluminum, iron, copper, calcium or magnesium.

In detail, the ultrasonic device may include an ultrasonic oscillating groove or an ultrasonic amplifier. Table 1 contains experimental results of the dissolution rate of cobalt, manganese, nickel and lithium in a ternary positive electrode material powder using an ultrasonic amplifier and an ultrasonic oscillating groove, wherein the power of the ultrasonic amplifier is 800 W. The frequency is 20,000 Hz, which is a single point vibration, the amplitude rod is 1/2 吋, the power of the ultrasonic oscillating groove is 200 W, the frequency is 53000 Hz, which is a water bath oscillation. The ratio of cobalt, manganese, nickel and lithium is 2:3. :5:10.

Experiment 0 was set up with 200 ml of a sulfuric acid solution having a concentration of 3.6 N, placed in a 250 ml beaker, and 5 g of a ternary positive electrode material powder was added. After adding 2.5 ml of hydrogen peroxide per hour, the solution was acid-dissolved for 4 hours at a temperature of 55 ° C and a stirring speed of 400 rpm using a magnet mixer. Finally, the dissolution concentration was measured by a flame atomic absorption spectrometer to calculate the dissolution rate.

The settings of Experiment 1 and Experiment 2 are the same as those of Experiment 0. The difference is that Experiment 1 observes that no hydrogen peroxide is added for acid dissolution, and Experiment 2 observes the use of ultrasonic amplifier without hydrogen peroxide. The acid dissolution rate was 50%, and the ultrasonic power was continuously dissolved for 4 hours in a discontinuous operation mode of 5 seconds per 5 seconds of vibration. In experiment 3, the remaining cobalt and manganese in the experiment 2 were contained. Percentage of nickel or lithium powder.

According to Experiment 3, according to the treatment conditions, the acid immersion liquid only dissolves cobalt, nickel and manganese below 1%, that is, the ultrasonic amplifier can hardly dissolve manganese, in other words, the ultrasonic amplifier can be directly used. Acid leaching of cobalt and nickel, the effect of this can be omitted. In the prior art, manganese, cobalt, nickel should be extracted and separated into a manganese solution and a cobalt and nickel solution, and then extracted and separated into a cobalt solution and a nickel solution. Two-stage extraction process. Ultrasonic amplifier is acid soluble to separate manganese, acid immersion liquid only needs extraction The one-stage extraction process, which is separated into a cobalt solution and a nickel solution, can greatly reduce the amount of solvent operation during extraction.

In Experiments 4 to 8, ultrasonic wave oscillating tanks and magnet mixers were used to separate the acid dissolution rate, and 0.25 ml, 0.5 ml, 1.25 ml, and 0.5 ml were added per hour in experiments 5, 6, 7, and 8. The hydrogen peroxide was set at a temperature of 55 degrees Celsius and acid-dissolved for 4 hours. Finally, the dissolution concentration was measured by a flame atomic absorption spectrometer to calculate the dissolution rate.

It can be seen from the experimental results that when the ultrasonic oscillating tank is used to assist in the dissolution of the positive electrode material, only the original 20% hydrogen peroxide can be used to dissolve manganese, cobalt, nickel and lithium, which can greatly reduce the amount of hydrogen peroxide used.

Please refer to FIG. 2A to FIG. 2C , which are a first schematic diagram, a second schematic diagram and a third schematic diagram of an acid-soluble extraction metal concentration according to another embodiment of the present invention. The same experimental method was carried out by immersing 10 g of the positive electrode material in 4.0 N of H ₂ SO ₄ , except that in FIG. 2A, 10 ml of hydrochloric acid was further added and heated to 65° C. (between plus and minus 5 degrees) and stirred for 8 hours. Figure 2B does not add 10ml of hydrochloric acid and heated to 65 degrees C (between plus and minus 5 degrees) and stirred for 8 hours, while adding 2.5ml of hydrogen peroxide (concentration of 35%) in the first hour, the second C chart is not added 10 ml of hydrochloric acid was heated to 50 ° C (between plus and minus 5 degrees) and stirred for 3 hours while 2.5 ml of hydrogen peroxide (concentration 35%) was added every hour.

Fig. 2A represents a method of eluting a valuable metal used in the prior art, Fig. 2B is a combination of hydrogen peroxide and a conventional dissolution method, and Fig. 2C is a step of abandoning the conventional addition of hydrochloric acid for acid dissolution, using a sequential addition of 35%. The concentration of hydrogen peroxide, and the volume ratio of hydrogen peroxide to sulfuric acid is 1:100, at which the concentration of the valuable metal eluted is the highest, and the concentration of the valuable metal eluted by the prior art is the lowest. Therefore, it can be seen that hydrogen peroxide and sulfuric acid greatly contribute to the dissolution of metal in metal oxides, and when the temperature is raised, the dissolution of metal in metal oxides by sulfuric acid can be promoted, and hydrochloric acid can also produce slight synergy with sulfuric acid. effect.

Please refer to FIG. 3A to FIG. 3C , which are a first schematic diagram, a second schematic diagram and a third schematic diagram of solvent extraction and stripping according to a second embodiment of the present invention. The positive electrode material is dissolved in the oxide solid by an acid solution procedure, followed by solvent extraction to separate manganese, cobalt, nickel and lithium. Among them, when separating manganese, D2EHPA can be used for extraction and acid stripping. The experimental conditions are as follows: D2EHPA (P204 in the figure means D2EHPA) and kerosene mixed in a volume ratio of 3:7 as extractant, oil-water ratio (O/A) ), the different pH values of 2.5 to 3.8 were adjusted, and the main metal ion concentration of the raffinate was detected after 30 min oscillation extraction equilibrium. As shown in Figure 3A, manganese is easily captured by D2EHPA extractant relative to cobalt, nickel and lithium, and the higher the pH (so the best pH2.5), the higher the extraction rate of manganese, but accompanied by The extraction rate of cobalt, nickel and lithium will also increase. Therefore, the extraction equilibrium is required to operate at a low extraction rate (zone A), while the high extraction rate is accompanied by a low purity recovery (zone B). To operate at high extraction rates simultaneously and to recover high purity materials, cross-flow extraction, reverse cascade extraction or batch cycle extraction and stripping are required.

Figure 3B shows the high amount of manganese oil phase liquid obtained by extracting D2EHPA with different equivalents. The sulfuric acid of degree 0.1, 0.4, 0.7, 1.0, 1.5, 2.0 N was subjected to back extraction. The oil-water ratio (O/A) of the experiment was 5, and back extraction was continued using different equivalents of sulfuric acid, and the main metal ion concentration of each equivalent stripping solution was separately measured. In the 1.0 N sulfuric acid stripping solution, it is sufficient to strip the high amount of manganese in the D2EHPA extracted oil phase liquid to the aqueous phase for subsequent resource conversion to the metal manganese or manganese salt. The equivalent concentration of the stripping solution should be appropriately selected, the equivalent concentration is too low, and the stripping rate of manganese is low; if the equivalent concentration is too high, the pH value of the D2EHPA extracting agent is too low, and the subsequent cyclic extraction requires a large adjustment of the pH value.

As shown in Fig. 3C, the experimental conditions were as follows: D2EHPA and kerosene were mixed at a volume ratio of 3:7 as an extractant, and the oil-water ratio (O/A) was 1, adjusted to pH 5, and after 30 min of shaking extraction and equilibration, respectively. The main metal ion concentration of the raffinate is detected. After the extractant is back-extracted with 2.0 N sulfuric acid, the original raffinate is extracted again by circulation, and the total extraction and back extraction are performed three times. The extraction ratio of each metal ion was calculated from the difference in concentration of each metal ion before and after the extraction of the solution containing manganese, cobalt, and nickel.

The solution containing manganese, cobalt and nickel in the D2EHPA extractant, after batch batch extraction, the manganese extraction rate of the solution containing manganese, cobalt and nickel, after three cycles of extraction and stripping, from 40.84% to 71.75 % and 89.00%, while the extraction rate of other metals is maintained at a low level of change. Therefore, the three-cycle extraction and stripping can effectively increase the extraction rate of manganese, and maintain the other impurities in the extracted manganese solution at a low level. At this time, the pH of the solution is adjusted by a redox reaction to precipitate manganese and recovered by filtering manganese into a solid salt form.

Cobalt can be recovered by a similar method. HEHEHP and kerosene are mixed in a 2:8 volume ratio as an extractant containing cobalt, nickel and lithium solutions. The oil-water ratio (O/A) is 1, and the pH is adjusted to 5. , after three cycles of extraction and stripping. The 1.5N sulfuric acid stripping solution has an oil to water ratio (O/A) of 1, which is sufficient to strip the high amount of cobalt in the HEHEHP extracted oil phase liquid to the aqueous phase. The water is reversely extracted and the solution is electrolyzed to recover cobalt. The anode is made of insoluble anode, the cathode is made of stainless steel, the effective electrolytic area of the electrode is 36 cm ² , the electrolyte pH is 4.5, the bath temperature is 50 ° C, the current density is 1.5 A/dm ² , and the electrolysis time is 48. In an hour, a purity of 97.7% metallic cobalt can be obtained. Figure 4 shows the difference in concentration of each metal ion before and after each extraction of the cobalt, nickel and lithium solutions, and shows the extraction rate of each metal ion. Fig. 5A and Fig. 5B are schematic diagrams showing the concentration of the metal obtained in the first stripping and the second stripping, respectively, and the equivalent concentration of the stripping solution.

Different from the conventional techniques for acid dissolution using sulfuric acid or hydrochloric acid, the present invention discloses a new acid solution for increasing the dissolution rate of valuable metals such as cobalt, manganese and nickel. After repeated tests, the inventors discovered that secondary lithium batteries are discarded. When the pool recovers the valuable metal, the dissolution rate of the valuable metal can be increased by adding hydrogen peroxide to the sulfuric acid in the acid solution process, which is characterized in that the hydrogen peroxide is mixed with the sulfuric acid solution, and the experimental example is the volume of 35% hydrogen peroxide and sulfuric acid. The ratio is set to 1:100, and combined with electrolysis or chemical precipitation reaction, high-concentration metals such as manganese, cobalt or nickel can be recovered from the waste secondary lithium battery.

The present invention has been particularly shown and described with reference to the exemplary embodiments thereof, and it is understood by those of ordinary skill in the art Various changes in form and detail can be made in the context of the category.

The embodiments described above are merely illustrative of the technical spirit and the features of the present invention, and the objects of the present invention can be understood by those skilled in the art, and the scope of the present invention cannot be limited thereto. That is, the equivalent variations or modifications made by the spirit of the present invention should still be included in the scope of the present invention.

S1~S6‧‧‧Steps

Claims (10)

The invention relates to a method for recovering valuable metals, which is suitable for a positive electrode material of a waste secondary lithium battery. The method for recovering valuable metals comprises: forming a positive manganese material containing manganese, cobalt, nickel by a discharge process and a pulverization sorting process. a powder of aluminum and lithium; mixing the powder with an acid containing sulfuric acid but not containing hydrogen peroxide to impregnate an acid impregnation solution, wherein the ratio of the acid solution to the powder is between 1 g/100 ml and 4 g Between /100ml, the acid solution and the powder system are placed in an ultrasonic amplifier, the concentration of sulfuric acid in the acid solution is between 3N and 4N, and the temperature of the acid solution mixed with the powder is between 45 degrees Celsius. Between 55 degrees, the acid immersion liquid contains less than 1% manganese; the acid immersion liquid is extracted with manganese, cobalt, nickel and lithium by an extracting agent to form a first oil phase solution containing manganese and a first aqueous phase raffinate containing cobalt, nickel and lithium; extracting cobalt in the first aqueous phase raffinate to separately form a second oil phase solution containing cobalt and a second containing nickel and lithium The aqueous phase extracts the remaining liquid; and utilizes a recycling procedure to separate from the first a stripping solution of the phase solution, a stripping solution of the second oil phase solution, and a second aqueous phase raffinate recovering manganese, cobalt, nickel and lithium, wherein the recovery procedure comprises a chemical precipitation reaction or an electrolytic reaction . The method for recovering valuable metals according to claim 1, wherein the chemical precipitation reaction precipitates metal ions by a redox reaction, which reduces metal ions to metal elements. The method for recovering a valuable metal according to claim 2, wherein the redox reaction comprises a stripping solution of the first oil phase solution or a stripping solution of the second oil phase solution or the second The aqueous phase raffinate is subjected to adjustment of one of different pH values to precipitate cobalt, manganese or nickel, and the cobalt, manganese or nickel is recovered by filtration in the form of a solid salt, and the pH range is between 2.0~11.0. The method for recovering valuable metals according to claim 3, further comprising dissolving the solid salt in an electrolyte for electrolytically refining cobalt, manganese or nickel. The method of recovering a valuable metal according to claim 1, wherein the extracting agent comprises D2EHPA or Cyanex272. The method for recovering valuable metals according to claim 1, wherein the frequency of the ultrasonic amplifier is between 20 kHz and 28 kHz. The invention relates to a method for recovering valuable metals, which is suitable for a positive electrode material of a waste secondary lithium battery. The method for recovering valuable metals comprises: forming a positive manganese material containing manganese, cobalt, nickel by a discharge process and a pulverization sorting process. a powder of aluminum and lithium; using an alkali-soluble procedure to precipitate and remove the aluminum metal in the powder; mixing the powder with an acid containing sulfuric acid to impregnate an acid containing manganese, cobalt, nickel and lithium a liquid, wherein the ratio of the acid solution to the powder is between 1 g/100 ml and 4 g/100 ml, and the acid solution and the powder system are placed in an ultrasonic device for mixing and 0.25 ml is added every hour. 2.5ml, a concentration of 35% hydrogen peroxide, the concentration of sulfuric acid in the acid solution is between 3N and 4N, the temperature of the acid solution mixed with the powder is between 45 degrees Celsius and 55 degrees Celsius between; Extracting the acid immersion liquid with manganese, cobalt, nickel and lithium by using an extracting agent to form a first oil phase solution containing manganese and a first aqueous phase raffinate containing cobalt, nickel and lithium; Cobalt in the first aqueous phase raffinate is extracted to separately form a second oil phase solution containing cobalt and a second aqueous phase raffinate containing nickel and lithium; and utilizing a recovery procedure to separately from the first oil a stripping solution of the phase solution, a stripping solution of the second oil phase solution, and a second aqueous phase raffinate recovering manganese, cobalt, nickel and lithium, wherein the recovery procedure comprises a chemical precipitation reaction or an electrolytic reaction . The method for recovering valuable metals according to claim 7, wherein the ultrasonic device comprises an ultrasonic oscillating groove or an ultrasonic amplifier. The method for recovering valuable metals according to claim 8 , wherein the frequency of the ultrasonic oscillation tank is between 28 kHz and 200 kHz, and the frequency of the ultrasonic amplifier is between 20 kHz and 28 kHz. The method for recovering valuable metals according to claim 7, wherein the hydrogen peroxide dissolution reaction formula is 2LiCoO ₂ +3H ₂ SO ₄ +H ₂ O ₂ =Li ₂ SO ₄ +2CoSO ₄ +O ₂ ↑+ 4H ₂ O _(l) .