METHOD FOR TREATING SCRAPPED POSITIVE ELECTRODE SLURRY, AND APPLICATION

Abstract

A treatment method of scrapped positive electrode slurry, includes the following steps: pretreating the scrapped positive electrode slurry to obtain a slurry solution; performing electrophoresis coagulation and filter pressing on the slurry solution to obtain a liquid phase and a solid phase; and performing gradient roasting on the solid phase to obtain a positive electrode material.

Claims

1. A treatment method of scrapped positive electrode slurry, comprising the following steps: (1) pretreating the scrapped positive electrode slurry to obtain a slurry solution; (2) performing electrophoresis coagulation and filter pressing on the slurry solution to obtain a liquid phase and a solid phase; and (3) performing gradient roasting on the solid phase to obtain a positive electrode material; wherein in the step (1), the pretreating comprises the specific steps: separating out bagged materials from the scrapped positive electrode slurry, and crushing and sorting the bagged materials to obtain the slurry solution; wherein in the step (2), a direct current used in the process of performing electrophoresis coagulation has a current of 50-70 mA and a voltage of 60-65 V, the direct current used in the process of performing electrophoresis coagulation has a current density of 0.2-0.6 A/m.sup.2, and a time of the electrophoresis in the step (2) is 20-60 min; and wherein in the step (3), a specific process of the gradient roasting is roasting the solid phase at three stages, wherein first-stage roasting is performed at 80-100 C. for 20-60 min, second-stage roasting is performed at 200-250 C. for 30-60 min, and third-stage roasting is performed at 350-450 C. for 30-60 min, so as to obtain the positive electrode material, and the treatment method further comprising, after the second-stage roasting, condensing gas obtained by roasting, and recycling NMP.

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

6. The treatment method of claim 1, wherein the step (2) further comprises performing distillation on the liquid phase, and enriching an organic phase to obtain NMP with a purity larger than 70%.

7. The treatment method of claim 6, wherein the distillation is reduced pressure rotary evaporation or rectification.

8-18. (canceled)

Description

DETAILED DESCRIPTION

[0035] Hereinafter, the concept of the present disclosure and the resulting technical effects will be clearly and completely described with reference to embodiments to fully understand the objectives, features and effects of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure and not all embodiments. Based on the embodiments of the present disclosure, other embodiments obtained by those skilled in the art without involving any inventive effort are within the scope of the present disclosure.

Embodiment 1

[0036] A treatment method of scrapped positive electrode slurry of this embodiment included the following steps: [0037] (1) putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0038] (2) placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.2 A/m.sup.2 for 30 min of electrophoresis, and performing suction filtration on the slurry to obtain a liquid phase and a solid phase; [0039] (3) performing reduced pressure rotary evaporation on the liquid phase for 60 min under the conditions of a gauge pressure of 0.02 MPa and a temperature of 60 C. to obtain an organic phase and an aqueous phase; and [0040] (4) placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 20 min at 80 C. to remove moisture, then increasing the temperature to 200 C. to continue roasting for 40 min, recycling NMP through condensation, finally, performing roasting for 60 min at 400 C. to remove a binder PVDF, and taking out a positive electrode material after a system was cooled to normal temperature.

[0041] The organic phase and the aqueous phase which were obtained after rotary evaporation were analyzed by using a brs-nmp type handheld NMP concentration detector. The concentration of NMP in the organic phase was 83%, and the concentration of NMP in the aqueous phase was 6%. The concentration of the NMP recycled through concentration was 87%.

[0042] A solid ignition loss rate of the positive electrode material of this embodiment was 0.29%. An ignition loss rate test method referred to Solid wast-Determination of loss on ignition-Gravimetric method (HJ1024-2019).

Embodiment 2

[0043] A treatment method of scrapped positive electrode slurry of this embodiment included the following steps: [0044] (1) putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0045] (2) placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.5 A/m.sup.2 for 40 min of electrophoresis, and performing suction filtration on the coagulated slurry to obtain a liquid phase and a solid phase; [0046] (3) performing reduced pressure rotary evaporation on the liquid phase for 60 min under the conditions of a gauge pressure of 0.02 MPa and a temperature of 60 C. to obtain an organic phase and an aqueous phase; and [0047] (4) placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 20 min at 80 C. to remove moisture, then increasing the temperature to 200 C. to continue roasting for 40 min, recycling NMP through condensation, finally, performing roasting for 60 min at 400 C. to remove a binder PVDF, and taking out a positive electrode material after a system was cooled to normal temperature.

[0048] The organic phase and the aqueous phase which were obtained after rotary evaporation were analyzed by using a brs-nmp type handheld NMP concentration detector. The concentration of NMP in the organic phase was 83%, and the concentration of NMP in the aqueous phase was 6%. The concentration of the NMP recycled through concentration was 87%.

[0049] A solid ignition loss rate of the positive electrode material of this embodiment was 0.15%. An ignition loss rate test method referred to Solid wast-Determination of loss on ignition-Gravimetric method (HJ1024-2019).

Embodiment 3

[0050] A treatment method of scrapped positive electrode slurry of this embodiment included the following steps: [0051] (1) putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0052] (2) placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.6 A/m.sup.2 for 40 min of electrophoresis, and performing suction filtration on the coagulated slurry to obtain a liquid phase and a solid phase; [0053] (3) performing reduced pressure rotary evaporation on the liquid phase for 60 min under the conditions of a gauge pressure of 0.02 MPa and a temperature of 80 C. to obtain an organic phase and an aqueous phase; and [0054] (4) placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 20 min at 80 C. to remove moisture, then increasing the temperature to 200 C. to continue roasting for 40 min, recycling NMP through condensation, finally, performing roasting for 60 min at 400 C. to remove a binder PVDF, and taking out a positive electrode material after a system was cooled to normal temperature.

[0055] The organic phase and the aqueous phase which were obtained after rotary evaporation were analyzed by using a brs-nmp type handheld NMP concentration detector. The concentration of NMP in the organic phase was 88%, and the concentration of NMP in the aqueous phase was 13%. The concentration of the NMP recycled through concentration was 85%.

[0056] A solid ignition loss rate of the positive electrode material of this embodiment was 0.33%. An ignition loss rate test method referred to Solid wast-Determination of loss on ignition-Gravimetric method (HJ1024-2019).

Embodiment 4

[0057] A treatment method of scrapped positive electrode slurry of this embodiment included the following steps: [0058] (1) putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0059] (2) placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.2 A/m.sup.2 for 60 min of electrophoresis, and performing suction filtration on the coagulated slurry to obtain a liquid phase and a solid phase; [0060] (3) performing reduced pressure rotary evaporation on the liquid phase for 30 min under the conditions of a gauge pressure of 0.01 MPa and a temperature of 80 C. to obtain an organic phase and an aqueous phase; and [0061] (4) placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 20 min at 80 C. to remove moisture, then increasing the temperature to 200 C. to continue roasting for 40 min, recycling NMP through condensation, finally, performing roasting for 60 min at 400 C. to remove a binder PVDF, and taking out a positive electrode material after a system was cooled to normal temperature.

[0062] The organic phase and the aqueous phase which were obtained after rotary evaporation were analyzed by using a brs-nmp type handheld NMP concentration detector. The concentration of NMP in the organic phase was 81%, and the concentration of NMP in the aqueous phase was 7%. The concentration of the NMP recycled through concentration was 89%.

[0063] A solid ignition loss rate of the positive electrode material of this embodiment was 0.42%. An ignition loss rate test method referred to Solid wast-Determination of loss on ignition-Gravimetric method (HJ1024-2019).

Embodiment 5

[0064] A treatment method of scrapped positive electrode slurry of this embodiment included the following steps: [0065] (1) putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0066] (2) placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.2 A/m.sup.2 for 60 min of electrophoresis, and performing suction filtration on the coagulated slurry to obtain a liquid phase and a solid phase; [0067] (3) rectifying the liquid phase to obtain an organic phase and an aqueous phase, wherein pH of the liquid phase is 7.0-10.0, pressure of an evaporation pot is 7.5 kPa, a reflux ratio was 2.5. [0068] (4) placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 30 min at 80 C. to remove moisture, then increasing the temperature to 200 C. to continue roasting for 40 min, recycling NMP through condensation, finally, performing roasting for 60 min at 400 C. to remove a binder PVDF, and taking out a positive electrode material after a system was cooled to normal temperature.

[0069] The organic phase and the aqueous phase which were obtained after rectification were analyzed by using a brs-nmp type handheld NMP concentration detector. The concentration of NMP in the organic phase was 99.5%, and the concentration of NMP in the aqueous phase was 1.2%. The concentration of the NMP recycled through concentration was 88%.

[0070] A solid ignition loss rate of the positive electrode material of this embodiment was 0.33%. An ignition loss rate test method referred to Solid wast-Determination of loss on ignition-Gravimetric method (HJ1024-2019).

Embodiment 6

[0071] A treatment method of scrapped positive electrode slurry of this embodiment included the following steps: [0072] (1) putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0073] (2) placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.2 A/m.sup.2 for 60 min of electrophoresis, and performing suction filtration on the coagulated slurry to obtain a liquid phase and a solid phase; [0074] (3) performing reduced pressure rotary evaporation on the liquid phase for 30 min under the conditions of a gauge pressure of 0.01 MPa and a temperature of 80 C. to obtain an organic phase and an aqueous phase; and [0075] (4) placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 60 min at 100 C. to remove moisture, then increasing the temperature to 220 C. to continue roasting for 30 min, recycling NMP through condensation, finally, performing roasting for 30 min at 400 C. to remove a binder PVDF, and taking out a positive electrode material after a system was cooled to normal temperature.

[0076] The organic phase and the aqueous phase which were obtained after rotary evaporation were analyzed by using a brs-nmp type handheld NMP concentration detector. The concentration of NMP in the organic phase was 85%, and the concentration of NMP in the aqueous phase was 6%. The concentration of the NMP recycled through concentration was 87%.

[0077] A solid ignition loss rate of the positive electrode material of this embodiment was 0.36%, and energy consumption was 0.38 kwh.

Comparative Example 1

[0078] A treatment method of scrapped positive electrode slurry of this Comparative Example included the following steps: [0079] putting the scrapped positive electrode slurry into an iron basket to separate out bagged materials, and crushing and sorting the bagged materials to obtain a slurry solution; [0080] placing the slurry solution obtained after crushing and sorting into an electrophoresis tank, starting a direct current power source, adjusting a current density to 0.2 A/m.sup.2 for 60 min of electrophoresis, and performing suction filtration on the coagulated slurry to obtain a liquid phase and a solid phase; [0081] performing reduced pressure rotary evaporation on the liquid phase for 30 min under the conditions of a gauge pressure of 0.01 MPa and a temperature of 80 C. to obtain an organic phase and an aqueous phase; and [0082] placing the solid phase into a tube furnace equipped with a condensation gas collecting device, performing roasting for 120 min at 400 C. to remove moisture, and taking out a positive electrode material after a system was cooled to normal temperature.

[0083] A solid ignition loss rate of this Comparative Example was 0.36%, and energy consumption was 0.51 kwh. No independent NMP organic phase was produced in the roasting process.

[0084] In conclusion, the present disclosure recycles the scrapped positive electrode slurry by creatively combining the crushing, sorting, electrophoresis and gradient roasting processes. Liquid-solid separation is thorough, and an NMP organic phase can be directly obtained. The economic value is high, and the organic content of the produced positive electrode material is low. The concentration of NMP in either the organic phase recycled through condensation or the organic phase in the rotary evaporation/rectification process is larger than 80%, and an ignition loss rate of the positive electrode material is smaller than 0.5%.

[0085] The embodiments of the present disclosure are described in detail above, the present disclosure is not limited to the embodiments described above and various changes can be made without departing from the scope of the present disclosure within the range of knowledge of those of ordinary skill in the art. Furthermore, the embodiments of the present disclosure and features in the embodiments may be combined with one another if there is no conflict.