METHOD OF TARGETED RECYCLING OF WASTE BATTERIES

Abstract

The invention provides a targeted recycling method for waste battery, which comprises the following steps: the positive electrode strip of the waste battery is broken to obtain the broken product; In a carbon monoxide atmosphere, the broken product is pyrolyzed to obtain the pyrolysis product, and then the pyrolysis product is magnetically separated to obtain the magnetic separation product to achieve valuable metal recovery; The pyrolysis gas of the pyrolysis is passed into an alkaline solution to obtain a Li-rich solution and realize Li recovery. The method induces the directional transfer of solid oxygen in the waste cathode material through pyrolysis to form a coexistence environment of Co and Al.sub.2O.sub.3, effectively inhibits the high temperature alloying, and at the same time, the high temperature complex reaction of CO and the newborn Co particle is used to induce the targeted aggregation of cobalt nanoparticles against the concentration gradient of CO to form millimeter-sized particles, so as to realize magnetic separation and recovery. At the same time, the method of the invention can realize industrial application.

Claims

1. A method of target recycling of waste batteries, characterized in that said method comprises the following steps: (1) crushing the positive electrode strip of the waste battery to obtain a crushing product; (2) pyrolyzing the crushing product described in step (1) under a CO atmosphere to obtain a pyrolysis product, and then magnetically separating the pyrolysis product to obtain a magnetic separation product to realize valuable metal recovery; (3) Passing the pyrolysis gas of the pyrolysis described in step (2) into an alkaline solution to obtain a Li-rich solution, realizing Li recovery.

2. The method according to claim 1, characterized in that in the CO atmosphere referred to in step (2), the gas pressure of the CO is 10-800 Pa, preferably 100-500 Pa; Preferably, said CO atmosphere of step (2) is a low-vacuum CO atmosphere, said low-vacuum CO atmosphere being formed by passing CO at 10-800 Pa under vacuum conditions; Preferably, the source of CO gas in said CO atmosphere of step (2) comprises pyrolysis gas of biomass.

3. The method according to claim 1, characterized in that the reducing agent for pyrolysis said in step (2) comprises a collector fluid of said positive electrode strip; Preferably, said collector is Al foil; Preferably, said complexing agent for pyrolysis of step (2) comprises CO.

4. The method according to claim 1, characterized in that said pyrolysis of step (2) comprises a primary warming up to a first temperature, followed by a secondary warming up to a second temperature, and finally a cooling down.

5. The method according to claim 4, characterized in that said first temperature is 400-600 C. and the holding time at the first temperature is 20-40 min; Preferably, the rate of heating of said primary temperature is 15-25 C./min.

6. The method according to claim 4, characterized in that said second temperature is 700-900 C. and the holding time at the second temperature is 50-70 min; Preferably, said rate of increase in temperature of said second temperature is 5-15 C./min; Preferably, said cooling down to 20-35 C.

7. The method according to claim 1, characterized in that said magnetic separation product of step (2) comprises magnetically selected Co powder and non-magnetically selected LiAlO.sub.2; Preferably, said alkaline solution of step (3) comprises a Ca(OH).sub.2 solution; Preferably, the concentration of Li in said Li-rich solution of step (3) is 5-10 g/L.

8. The method according to claim 1, characterized in that the waste battery described in step (1) is first physically short-circuited and discharged, then immersed in a salt solution and discharged, and finally dried and disassembled to obtain the positive electrode strip; Preferably, the manner of crushing described in step (1) comprises shear crushing.

9. The method according to claim 1, characterized in that the waste battery described in step (1) comprises a waste lithium cobaltate batteries.

10. The method according to claim 1, characterized in that said method comprises the following steps: (1) physically short-circuiting and discharging the waste battery, then discharging it by immersing it in a salt solution, and finally drying and disassembling it to obtain a positive electrode strip, and shearing and crushing said positive electrode strip to obtain a crushing product; (2) under vacuum conditions, pass in CO of 10-800 Pa to form a low vacuum CO atmosphere, under said low vacuum CO atmosphere, the crushing product described in step (1) is heated up once to 400-600 C. at a heating rate of 15-25 C./min, held at a temperature of 20-40 min, and then heated up twice at a heating rate of 5-15 C./min to 700-900 C., hold the temperature for 50-70 min and then reduce the temperature to 20-35 C., complete the pyrolysis, and obtain the pyrolysis product; (3) magnetically selecting the pyrolysis product described in step (2) to obtain magnetically selected Co powder and non-magnetically selected LiAlO.sub.2; (4) Passing the pyrolysis gas of the pyrolysis described in step (2) into a Ca(OH).sub.2 solution to obtain a Li-rich solution with a Li concentration of 5-10 g/L.

Description

DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0046] FIG. 1 shows a flow chart of the method described in Example 1 of the present invention;

[0047] FIG. 2 shows a scanning electron micrograph of the movement of Co metal nanoparticles during the pyrolysis process described in Example 1 of the present invention;

[0048] FIG. 3 shows an optical effect diagram of the positive electrode strip before pyrolysis as described in Example 1 of the present invention;

[0049] FIG. 4 shows an optical effect diagram of the targeted aggregation of Co metal nanoparticles after the pyrolysis described in Example 1 of the present invention.

SPECIFIC EMBODIMENTS

[0050] The technical embodiments of the present invention are further described below by way of specific embodiments. It should be clear to those skilled in the art that the described embodiments are merely to aid in the understanding of the present invention and should not be regarded as a specific limitation of the present invention.

Embodiment 1

[0051] This embodiment provides a method of targeting recycling of used batteries, a flow chart of said method is shown in FIG. 1, comprising the following steps: [0052] (1) In order to ensure the safety of the experimental process, the waste Li batteries are safely discharged, specifically 100 blocks of about 2.5 kg of waste Li Coate mobile phone Li batteries are first discharged by a physical short circuit for 12 hours, and then immersed in a 5% NaCl salt solution to be fully discharged for 48 hours, and then left to air dry in a fume cupboard for 48 hours; [0053] (2) The discharged lump waste Li batteries were disassembled manually in a fume hood, and 100 waste positive electrode strips were removed; [0054] (3) The discharged waste Li battery cathode strips were sheared and crushed to obtain 1600 g of crushed product; [0055] (4) under vacuum conditions, pass 200 Pa of CO to form a low vacuum CO atmosphere, in the pyrolysis furnace under said low vacuum CO atmosphere, the crushing product described in step (3) is heated up to 500 C. once at a heating rate of 20 C./min, after holding for 30 min, and then heated up to 800 C. twice at a heating rate of 10 C./min, after holding for 60 min spontaneous combustion cooling to 25 C., completing the low vacuum pyrolysis of CO, and obtaining a pyrolysis product; [0056] (5) magnetically selecting the pyrolysis product described in step (4) to obtain magnetically selected Co powder and non-magnetically selected LiAlO.sub.2; [0057] (6) Passing the pyrolysis gas of the pyrolysis described in step (4) into a 1 mol/L calcium hydroxide solution to obtain a Li-rich solution, said Li-rich solution being a LiOH-rich solution;

[0058] The scanning electron microscope diagram of the movement of the Co metal nanoparticles during the pyrolysis process described in the present invention is shown in FIG. 2, the optical effect diagram of the anode strip before said pyrolysis is shown in FIG. 3, and the optical effect diagram of the targeted aggregation of the Co metal nanoparticles after the pyrolysis is shown in FIG. 4.

[0059] The present invention has carried out a number of parallel experiments on Example 1 as follows: [0060] (1) Laboratory targeted pyrolysis experiment Group A: the recovery rate of Co in the Co powder product was 96.8%, the purity of the Co powder was 98.4%, the product purity of the LiAlO.sub.2 product was 95.5%, and the concentration of Li in the Li-rich solution was 6.3 g/L; [0061] (2) Laboratory targeted pyrolysis experiment Group B: the recovery rate of Co in Co powder products was 97.5%, the purity of Co powder was 99.0%, the product purity of LiAlO.sub.2 products was 95.6%, and the concentration of Li in Li-rich solution was 5.8 g/L; [0062] (3) Laboratory targeted pyrolysis experiment Group C: the recovery rate of Co in Co powder products was 98.3%, the purity of Co powder was 97.2%, the product purity of LiAlO.sub.2 products was 94.1%, and the concentration of Li in Li-rich solution was 7.1 g/L; [0063] (4) Laboratory targeted pyrolysis experiment Group D: the recovery rate of Co in Co powder products is 94.8%, the purity of Co powder is 98.8%, the product purity of LiAlO.sub.2 products is 97.5%, and the concentration of Li in Li-rich solution is 8.3 g/L; [0064] (5) Industrialized targeted pyrolysis pilot experiment Group A: the recovery rate of Co in Co powder products is 92.4%, the purity of Co powder is 94.7%, the product purity of LiAlO.sub.2 products is 93.7%, and the concentration of Li in Li-rich solution is 5.5 g/L; [0065] (6) Industrialized targeted pyrolysis pilot experiment Group A: the recovery rate of Co in Co powder products was 91.9%, the purity of Co powder was 95.2%, the product purity of AlLiO2 products was 96.5%, and the concentration of Li in Li-rich solution was 3.9 g/L; [0066] (7) Industrialized targeted pyrolysis pilot experiment Group A: the recovery rate of Co in Co powder products was 94.8%, the purity of Co powder was 95.8%, the product purity of LiAlO.sub.2 products was 92.7%, and the concentration of Li in Li-rich solution was 7.1 g/L; [0067] (8) Industrialized targeted pyrolysis pilot experiment Group A: the recovery rate of Co in the Co powder product was 93.3%, the purity of Co powder was 96.7%, the product purity of LiAlO.sub.2 product was 95.5%, and the concentration of Li in the Li-rich solution was 5.5 g/L.

[0068] The above results show that the method described in the present invention has excellent recovery effect, and the stability of the recovery effect is high, and it is also capable of industrial application.

Example 2

[0069] This embodiment provides a method of targeting recovery of waste batteries, said method comprising the following steps: [0070] (1) In order to ensure the safety of the experimental process, 100 blocks of about 2.5 kg of waste Li Coate mobile phone Li batteries are first discharged by a physical short circuit for 12 hours, and then immersed in a 5% NaCl salt solution to be fully discharged for 48 hours, and then air-dried in a fume hood for 48 hours; [0071] (2) The discharged lump waste Li batteries were disassembled manually in a fume hood, and 100 waste positive electrode strips were removed; [0072] (3) The discharged waste Li battery cathode strips were sheared and crushed to obtain 1600 g of crushed product; [0073] (4) under vacuum conditions, pass 200 Pa of CO to form a low vacuum CO atmosphere, in the pyrolysis furnace under said low vacuum CO atmosphere, the crushing product described in step (3) is heated up to 400 C. at a heating rate of 15 C./min once, held for 40 min, and then heated up to 900 C. at a heating rate of 15 C./min for a second time, and then held for 50 min spontaneous combustion cooling to 35 C., completing the pyrolysis, and obtaining the pyrolysis product; [0074] (5) magnetically selecting the pyrolysis product described in step (4) to obtain magnetically selected Co powder and non-magnetically selected LiAlO.sub.2; [0075] (6) passing the pyrolysis gas of the pyrolysis described in step (4) into a 1 mol/L calcium hydroxide solution to obtain a Li-rich solution, said Li-rich solution being a Li hydroxide-rich solution.

Embodiment 3

[0076] This embodiment provides a method of targeting recycling of waste batteries, said method comprising the following steps: [0077] (1) In order to ensure the safety of the experimental process, 100 blocks of about 2.5 kg of waste Li Coate mobile phone Li batteries are first discharged by physical short circuit for 12 hours, and then immersed in a 5% NaCl salt solution to be fully discharged for 48 hours, and then air-dried in a fume hood for 48 hours; [0078] (2) The discharged lump waste Li batteries were disassembled manually in a fume hood, and 100 waste positive electrode strips were removed; [0079] (3) The discharged waste Li battery cathode strips were sheared and crushed to obtain 1600 g of crushed product; [0080] (4) under vacuum conditions, pass 200 Pa of CO to form a low vacuum CO atmosphere, in the pyrolysis furnace under said low vacuum CO atmosphere, the crushing product described in step (3) is heated up to 600 C. once at a heating rate of 25 C./min, held for 20 min, then heated up to 700 C. for the second time at a heating rate of 5 C./min, and then held for 70 min spontaneous combustion cooling to 20 C., completing the pyrolysis, and obtaining the pyrolysis product; [0081] (5) magnetically selecting the pyrolysis product described in step (4) to obtain magnetically selected Co powder and non-magnetically selected LiAlO.sub.2; [0082] (6) Passing the pyrolysis gas of the pyrolysis described in step (4) into a 1 mol/L calcium hydroxide solution to obtain a Li-rich solution, said Li-rich solution being a LiOH-rich solution.

Embodiment 4

[0083] This embodiment provides a method of targeted recycling of used batteries, said method being the same as embodiment 1 except that step (4) is passed into 10 Pa of CO.

Embodiment 5

[0084] The present embodiment provides a method of targeted recycling of used batteries, said method being the same as embodiment 1 except that step (4) is passed into 100 Pa of CO.

Embodiment 6

[0085] The present embodiment provides a method of targeted recycling of used batteries, said method being the same as embodiment 1 except that step (4) passes through 500 Pa of CO.

Embodiment 7

[0086] The present embodiment provides a method of targeted recycling of used batteries, said method being the same as embodiment 1 except that step (4) passes through 800 Pa of CO.

Embodiment 8

[0087] The present embodiment provides a method of targeted recycling of used batteries, said method being the same as Example 1 except that step (4) passes through 1000 Pa of CO.

Comparative Example 1

[0088] The present contrasting proportion provides a method of targeted recycling of used batteries, said method being the same as Example 1 except that step (4) is passed into 200 Pa of carbon dioxide.

Comparative Ratio 2

[0089] The present contrasting ratio provides a method of targeted recycling of waste batteries, said method is the same as Example 1 except that step (4) is passed into 200 Pa of nitrogen.

[0090] The recovery efficiency of Co in the Co powder product obtained from the above embodiments and the relative proportion, the purity of the Co powder, the purity of the LiAlO.sub.2, and the concentration of Li in the Li-rich solution are shown in the following table:

TABLE-US-00001 TABLE 1 Recovery of Purity of Co Purity of Concentration of Li in Li- Co (%) powder (%) LiAlO.sub.2 (%) rich solution (g/L) Example 1 96.33 98.52 95.84 9.87 Example 2 95.78 95.21 94.75 8.85 Example 3 95.24 94.79 93.58 8.56 Example 4 93.05 96.89 93.23 8.45 Example 5 94.86 97.14 94.87 9.54 Example 6 94.88 97.84 95.45 9.41 Example 7 93.28 96.77 93.28 8.05 Example 8 88.75 75.84 78.92 3.28 Contrast ratio 1 75.88 69.94 75.42 4.21 Contrast ratio 2 64.43 53.81 56.87 3.75

[0091] As can be seen from Table 1:

[0092] As can be seen from Example 1 with counterparts 1-2, the CO atmosphere of the present invention is capable of effectively recovering metal Co powder and LiAlO.sub.2, which, combined with FIGS. 2-4, can demonstrate that the pyrolysis of the present invention is capable of inducing the Co nanoparticles to form millimeter-sized particles by targeting aggregation against the CO concentration gradient; as can be seen in Example 1 with Examples 4-8, the gas pressure of CO in the low-vacuum CO atmosphere of the present invention affects the effect of the pyrolysis and thus affect the recovery effect.

[0093] In summary, the present invention provides a method of targeting recovery of waste batteries, said method induces the solid oxygen in the waste cathode material to transfer directionally through pyrolysis to form a Co and Al.sub.2O.sub.3 coexistence environment, which effectively inhibits high temperature alloying, and at the same time, utilizes the high temperature complexation reaction between CO and nascent cobalt induce cobalt nanoparticles to target aggregation to form millimeter-sized large particles in reverse of the CO concentration gradient, thereby realizing magnetic separation and recovery.

[0094] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and technicians in the technical field should understand that any changes or substitutions that can be readily thought of by technicians in the technical field within the technical scope of the disclosure of the present invention fall within the scope of protection and disclosure of the present invention.