Process for treating carbon black

Abstract

The application discloses a kind of carbon black processing technology, carbon black is sequentially subjected to microwave treatment, laser etching, oxidation treatment, dialysis, freeze-drying treatment, and carbon dots are obtained.The particle size of carbon black particles is reduced by microwave treatment and laser etching; the hydrophilicity of carbon black particles is not good, and the dispersibility of carbon black particles in water is enhanced by oxidation treatment; the carbon black particles after oxidation treatment have more mixed acid and oxidant residues, which are separated and purified by dialysis to remove the residues; then freeze-drying is carried out to obtain carbon dots.The application is especially suitable for carbon black treatment in waste batteries, realizing high-value recovery and utilization of carbon black, and providing a new technical solution for waste battery recycling.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology, specifically relating to the recycling and treatment of carbon black in waste batteries. Background Technology

[0002] The recycling of used batteries is receiving increasing attention. However, current recycling efforts primarily focus on recovering valuable metals from used batteries, such as nickel, cobalt, manganese, and lithium. Research on the recycling of carbon black from used batteries is limited. Patent document CN109065999A discloses a method for recycling used lithium titanate batteries, separating a solution containing positive electrode material powder and a filter residue containing titanium and carbon black. Coke is added to the titanium and carbon black residue, chlorine gas is introduced, and a reaction yields liquid titanium tetrachloride. The remaining solid residue is used as a slurry for preparing positive and negative electrode active material powders. Patent document CN112142029A discloses a method for repairing and regenerating positive electrode materials from used lithium iron phosphate batteries. This method involves obtaining retired lithium iron phosphate powder through refined disassembly and calcining it by controlling the oxygen partial pressure to remove binders and carbon black components from the battery powder. Currently, carbon black recycling is not a primary focus in the field of used battery recycling. Summary of the Invention

[0003] The purpose of this invention is to provide a process for treating carbon black in waste batteries.

[0004] To achieve the above objectives, the present invention provides the following specific technical solutions.

[0005] A process for treating carbon black in waste batteries includes the following steps: The carbon black obtained from dismantling waste batteries is subjected to microwave treatment, laser etching, oxidation treatment, dialysis, and freeze-drying in sequence to obtain carbon dots.

[0006] In a further preferred embodiment, the power of the microwave treatment is 500W~3000W, and the microwave treatment time is 5min~60min.

[0007] In a further preferred embodiment, the laser etching uses an Nd:YAG solid-state laser to etch the microwave-treated powder, with a laser wavelength of 1064 nm, a pulse width of 80~160 ns, a frequency of 10~50 kHz, a power of 10~50 W, and a time of 5~30 mins.

[0008] In a further preferred embodiment, the specific process of the oxidation treatment is as follows: a mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a certain volume ratio, and then an oxidant and laser-etched carbon black are added to the mixed acid solution, and the oxidation treatment is carried out at 50-160℃ for 1-5 hours.

[0009] Furthermore, the oxidant is at least one of potassium permanganate, sodium perchlorate, and potassium persulfate.

[0010] Furthermore, the concentration of the concentrated sulfuric acid is 98 wt%, and the concentration of the concentrated nitric acid is 65 wt%.

[0011] Furthermore, the volume ratio of concentrated sulfuric acid to concentrated nitric acid in the mixed acid solution is 1:5 to 5:1.

[0012] Furthermore, the amount of oxidant added is 1~5g / 100ml of mixed acid solution.

[0013] Furthermore, the amount of laser-etched carbon black added to each 100 mL of mixed acid solution is 0.5~3 g.

[0014] In a further preferred embodiment, the specific process of dialysis is as follows: the material obtained after oxidation treatment is diluted with deionized water, the pH value is adjusted to 7-9, then solid-liquid separation is performed, the solid phase powder is placed in a dialysis bag, distilled water is placed outside the dialysis bag, and the distilled water outside the dialysis bag is replaced every once in a while.

[0015] Furthermore, the dialysis time is 120 min-900 min.

[0016] Furthermore, the distilled water outside the dialysis bag should be changed every 10 to 25 minutes.

[0017] Furthermore, the solid-liquid separation method is centrifugal separation.

[0018] In a further preferred embodiment, the specific process of the freeze-drying treatment is as follows: the powder obtained after dialysis is freeze-dried. The freeze-drying temperature is -15℃ to 50℃, and the time is 300 to 900 minutes.

[0019] The present invention has the following significant advantages: This invention innovatively discovers that carbon black in waste batteries can be processed through microwave treatment, laser etching, oxidation, dialysis, and freeze-drying to obtain carbon dots, thus realizing the high-value recycling and utilization of carbon black.

[0020] This invention provides new technical directions and ideas for the recycling of used batteries.

[0021] The present invention provides a simple and short process for processing carbon black into carbon dots. Attached Figure Description

[0022] Figure 1 The image shows the SEM image of the carbon dots obtained in Example 1.

[0023] Figure 2 This is a SEM image of the carbon dots obtained in Example 2.

[0024] Figure 3 This is a SEM image of the carbon dots obtained in Example 3.

[0025] Figure 4 This is a SEM image of the carbon dots obtained in Example 4. Detailed Implementation

[0026] This invention provides a process for treating carbon black in waste batteries, comprising the following steps: The carbon black obtained from dismantling waste batteries is subjected to microwave treatment, laser etching, oxidation treatment, dialysis, and freeze-drying in sequence to obtain carbon dots.

[0027] Those skilled in the art should understand that, based on the same inventive concept, the above-described processing technology is applicable to the treatment of all carbon black, and not just carbon black in waste batteries.

[0028] Carbon black particles have a relatively large particle size. Microwave treatment and laser etching are used to reduce the particle size. Since carbon black particles themselves have poor hydrophilicity, oxidation treatment is used to enhance their dispersibility in water. The oxidized carbon black particles retain a significant amount of mixed acid and oxidizing agent, which is removed by dialysis to separate and purify the residue. Finally, freeze-drying is used to obtain carbon dots. Compared to other drying methods, freeze-drying can preserve the morphology and specific structure of the carbon dots' surface, thus improving their performance.

[0029] In a specific embodiment of the present invention, the power of the microwave treatment is 500W~3000W, and can be selected from 500W, 1000W, 2000W, 3000W, etc., and the microwave treatment time is 5min~60min, which can be 5min, 10min, 30min, 60min, etc.

[0030] In a specific embodiment of the present invention, the laser etching uses an Nd:YAG solid-state laser to etch the microwave-treated powder. The laser wavelength is 1064nm, the pulse width is 80~160ns, the frequency is 10~50kHz, the power is 10~50W, and the time is 5~30 mins.

[0031] In a specific embodiment of the present invention, the specific process of the oxidation treatment is as follows: a mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a certain volume ratio, an oxidant is added to the mixed acid solution, and then microwave-treated carbon black is added, and the oxidation treatment is carried out at 50-160°C for 1-5 hours.

[0032] In practice, the concentration of concentrated sulfuric acid is 98%, and the concentration of concentrated nitric acid is 65% by mass.

[0033] In practical application, the oxidant is at least one of potassium permanganate, sodium perchlorate, and potassium persulfate; the amount of oxidant added is 1~5g / 100ml.

[0034] In practice, the amount of carbon black added to each 100 mL of mixed acid solution after laser etching is 0.5~3 g.

[0035] In a specific embodiment of the present invention, the dialysis process is as follows: the material obtained after oxidation treatment is diluted with deionized water, the pH value is adjusted to 7-9, then solid-liquid separation is performed, the solid phase powder is placed in a dialysis bag, distilled water is placed outside the dialysis bag, and the distilled water outside the dialysis bag is changed every once in a while.

[0036] In practice, the dialysis time is 120 min-900 min, and can be 120 min, 300 min, 600 min, 900 min, etc.

[0037] In practice, the distilled water outside the dialysis bag should be changed every 10 to 25 minutes. For example, you can choose to change the water every 10 minutes, 15 minutes, 20 minutes, or 25 minutes.

[0038] In practice, the solid-liquid separation method is centrifugal separation.

[0039] In a specific embodiment of the present invention, the freeze-drying process is as follows: the centrifuged powder is freeze-dried. In practice, the freeze-drying temperature is -15℃ to 50℃, and can be -50℃, -40℃, -25℃, -15℃, etc.; the freeze-drying time is 300~900min, and can be 300min, 480min, 720min, 900min, etc.

[0040] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0041] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0042] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0043] Example 1 Discharging used batteries.

[0044] Dismantle used batteries.

[0045] Waste batteries are crushed, sorted, acid-washed, and then filtered to obtain waste carbon black.

[0046] The obtained carbon black was microwaved at 2000W for 30 min and then laser etched (using an Nd:YAG solid-state laser to etch the microwave-treated powder; laser wavelength 1064nm, pulse width 100ns, frequency 25kHz, power 20W, time 10 mins). A mixed acid solution was prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a 3:1 volume ratio. 2g of potassium persulfate and 2g of laser-etched carbon black were added to 100mL of the mixed acid solution, and the mixture was oxidized at 80℃ for 2 h. The resulting turbid solution was diluted with deionized water, and the pH was adjusted to 8 with KOH solution. The solution was centrifuged using a benchtop high-speed refrigerated centrifuge. The centrifuged powder was placed in a dialysis bag filled with distilled water, and the water was changed every 15 min for a total dialysis time of 600 min. The solution was then freeze-dried at -50℃ for 720 min to obtain the final product, carbon dots.

[0047] Test and analyze the final product. Figure 1 This is a carbon dot SEM image.

[0048] Example 2 Discharging used batteries.

[0049] Dismantle used batteries.

[0050] Waste batteries are crushed, sorted, acid-washed, and then filtered to obtain waste carbon black.

[0051] The obtained carbon black was microwaved at 1000W for 60 min and then laser etched (using an Nd:YAG solid-state laser to etch the microwave-treated powder; laser wavelength 1064nm, pulse width 80ns, frequency 10kHz, power 40W, time 20 mins). A mixed acid solution was prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a 1:1 volume ratio. 4g of potassium permanganate and 0.5g of laser-etched carbon black were added to the mixed acid solution, and the mixture was then oxidized at 50℃ for 5 h. The resulting turbid solution was diluted with deionized water, and the pH was adjusted to 7 with KOH solution. The solution was centrifuged using a benchtop high-speed refrigerated centrifuge. The centrifuged powder was placed in a dialysis bag filled with distilled water, and the water was changed every 10 min for a total dialysis time of 300 min. The solution was then freeze-dried at -40℃ for 480 min to obtain the final product, carbon dots.

[0052] Test and analyze the final product. Figure 2 This is a carbon dot SEM image.

[0053] Example 3 Discharging used batteries.

[0054] Dismantle used batteries.

[0055] Waste batteries are crushed, sorted, acid-washed, and then filtered to obtain waste carbon black.

[0056] The obtained carbon black was microwaved at 500W for 10 min and then laser etched (using an Nd:YAG solid-state laser to etch the microwave-treated powder; laser wavelength 1064nm, pulse width 120ns, frequency 50kHz, power 50W, time 5mins). A mixed acid solution was prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a 1:5 volume ratio. 1g of sodium perchlorate and 3g of laser-etched carbon black were added to 100mL of the mixed acid solution, and then oxidized at 100℃ for 4 h. The turbid solution after oxidation was diluted with deionized water, adjusted to KOH solution to pH 9, and centrifuged using a benchtop high-speed refrigerated centrifuge. The centrifuged powder was placed in a dialysis bag filled with distilled water, and the distilled water was changed every 25 min for dialysis for 120 min. The powder was then freeze-dried at -25℃ for 300 min to obtain the final product, carbon dots.

[0057] Test and analyze the final product. Figure 3 This is an SEM image of carbon dots.

[0058] Example 4 Choose commercially available carbon black, for example, carbon black purchased from Crude's premises.

[0059] The obtained carbon black was microwaved at 3000W for 5 min and then laser etched (using an Nd:YAG solid-state laser to etch the microwave-treated powder; laser wavelength 1064nm, pulse width 160ns, frequency 25kHz, power 10W, time 30 mins). A mixed acid solution was prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a 5:1 volume ratio. 5g of potassium persulfate and 1g of laser-etched carbon black were added to 100mL of the mixed acid solution, and then oxidized at 160℃ for 2 h. The turbid solution after oxidation was diluted with deionized water, and the pH was adjusted to 8 with KOH solution. The solution was centrifuged using a benchtop high-speed refrigerated centrifuge. The centrifuged powder was placed in a dialysis bag filled with distilled water, and the water was changed every 20 min for a total dialysis time of 900 min. The solution was then freeze-dried at -15℃ for 900 min to obtain the final product, carbon dots.

[0060] Test and analyze the final product. Figure 4 This is an SEM image of carbon dots.

[0061] from Figures 1-4As can be seen, the final product consists of ultrafine (less than 10nm in size), dispersed, quasi-spherical carbon dots.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for treating carbon black in waste batteries, characterized in that, Includes the following steps: The carbon black obtained from dismantling waste batteries is subjected to microwave treatment, laser etching, oxidation treatment, dialysis, and freeze-drying in sequence to obtain carbon dots; The power of the microwave treatment is 500W~3000W, and the microwave treatment time is 5 min~60 min; The laser etching uses an Nd:YAG solid-state laser to etch the microwave-treated powder. The laser wavelength is 1064nm, the pulse width is 80~160ns, the frequency is 10~50kHz, the power is 10~50W, and the time is 5~30 mins. The specific process of the oxidation treatment is as follows: a mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a certain volume ratio, and then an oxidant and laser-etched carbon black are added to the mixed acid solution. The oxidation treatment is carried out at 50-160℃ for 1-5 hours. The oxidant is at least one of potassium permanganate, sodium perchlorate, and potassium persulfate. The specific process of dialysis is as follows: the material obtained after oxidation treatment is diluted with deionized water, the pH value is adjusted to 7-9, then solid-liquid separation is performed, the solid phase powder is placed in a dialysis bag, distilled water is placed outside the dialysis bag, and the distilled water outside the dialysis bag is changed every once in a while. The specific process of the freeze-drying treatment is as follows: the powder obtained after dialysis is freeze-dried; the freeze-drying temperature is -15℃ to 50℃, and the time is 300~900min.

2. The carbon black processing process as described in claim 1, characterized in that, The amount of oxidant added is 1~5g / 100ml of mixed acid solution.

3. The carbon black processing technology as described in claim 2, characterized in that, The amount of laser-etched carbon black added to each 100 mL of mixed acid solution is 0.5~3 g.

4. The carbon black processing process as described in claim 1, characterized in that, The dialysis time is 120 min-900 min; the distilled water outside the dialysis bag is changed every 10-25 min.

5. The carbon black processing process as described in claim 1, characterized in that, The solid-liquid separation method is centrifugal separation.

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