A method for extracting fullerenes from acetylene black conductive agent waste coke

Abstract

The present application relates to a method for extracting fullerene from acetylene black conductive agent waste coke. The method for extracting fullerene from acetylene black conductive agent waste coke comprises the following steps: heat treating the acetylene black conductive agent waste coke to obtain pretreated acetylene black conductive agent waste coke; under ultrasonic conditions, using an imidazole ionic liquid as an extractant to perform ultrasonic extraction treatment on the pretreated acetylene black conductive agent waste coke, separating, and obtaining an ionic liquid extract liquid rich in fullerene and a solid residue; performing gradient cooling crystallization treatment on the ionic liquid extract liquid rich in fullerene to obtain C 70 fullerene and C 60 fullerene. The present application realizes the recycling and utilization of acetylene black conductive agent waste coke, solves the problems of safety hazards and environmental pollution existing in the prior art of extracting fullerene, and solves the problems of complicated separation and purification steps, high energy consumption and long production cycle existing in the prior art of extracting fullerene.

Description

Technical Field

[0001] This invention relates to the field of nano-carbon material separation and purification technology, specifically to a method for extracting fullerenes from waste char of acetylene black conductive agent. Background Technology

[0002] Fullerene (C 60 C 70 As an important member of the carbon nanomaterial family, fullerenes (such as styrene, styrene, etc.) exhibit broad application prospects in semiconductors, biomedicine, energy storage, and catalysis due to their unique cage-like conjugated structure and excellent electron acceptor properties, antioxidant properties, and biocompatibility. However, the high cost of preparing high-purity fullerenes remains one of the main bottlenecks restricting their large-scale commercial application.

[0003] Currently, the industrial production of fullerenes mainly relies on extraction from soot produced by graphite arc discharge or hydrocarbon combustion methods, which requires complex solvent extraction and multi-stage chromatographic separation and purification. However, commonly used solvents (such as toluene, xylene, and other aromatic hydrocarbons) are not only highly toxic and volatile, posing safety hazards and environmental pollution risks, but also require long-term heating and reflux extraction, resulting in cumbersome subsequent separation and purification steps, high energy consumption, and long production cycles.

[0004] Acetylene black conductive agent is a commonly used conductive additive in lithium-ion batteries. It is a carbon black product obtained by thermally decomposing acetylene gas at high temperatures (approximately 1800℃). It possesses high purity, high conductivity, and a good chain-like particle structure, effectively improving the electronic conductivity of electrode materials. Waste coke is a byproduct generated during the production of acetylene black conductive agent, produced after the thermal decomposition of acetylene in a pyrolysis furnace. Specifically, it is generated during the decoking process after pyrolysis and is a residue that needs to be cleaned up during production. However, research shows that its microstructure often contains a certain proportion of fullerene-like cage-like carbon structures. If the waste coke of acetylene black conductive agent can be treated as an "urban mine" for high-value recycling and utilization, and the fullerene components can be effectively extracted, it can not only achieve the harmless disposal of industrial solid waste but also provide an alternative raw material source for the large-scale production of fullerenes, aligning with the strategic needs of circular economy and sustainable resource development. However, the release of fullerenes from the waste coke of acetylene black conductive agent is limited by its highly dense aggregated structure and strong interaction with amorphous carbon, making efficient separation difficult with traditional solvent extraction methods.

[0005] Therefore, developing a green, efficient, and low-cost method for extracting fullerenes from acetylene black conductive agent waste coke is of great significance for promoting the sustainable development of the fullerene industry and the recycling of industrial carbon resources. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for extracting fullerenes from acetylene black conductive agent waste coke, so as to realize the resource recycling of acetylene black conductive agent waste coke, and to solve the problems of safety hazards and environmental pollution that exist in existing fullerene extraction methods. It can also solve the problems of cumbersome separation and purification steps, high energy consumption and long production cycle in existing fullerene extraction methods.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Heat treatment of acetylene black conductive agent waste coke to obtain pretreated acetylene black conductive agent waste coke; S2. Under ultrasonic conditions, imidazole ionic liquids were used as extractants to perform ultrasonic extraction on pretreated acetylene black conductive agent waste coke, and the resulting ionic liquid extract rich in fullerenes and solid residue were obtained. S3. The ionic liquid extract rich in fullerenes is subjected to a stepped cooling crystallization process to obtain C. 70 Fullerenes and C 60 Fullerenes.

[0008] Based on the aforementioned technical methods, the waste coke of acetylene black conductive agent is first thermally treated. Utilizing the difference in thermal stability between fullerene and amorphous carbon (TRIZ separation principle), impurities are partially vaporized, increasing the fullerene content to 2-3%. Secondly, an imidazole-based ionic liquid with a fullerene solubility of 8-12 mg / mL (three times that of toluene) is used as the extractant. Simultaneously, an ultrasonic field is applied to generate cavitation, and microjets impact and break down carbon black aggregates, improving the mass transfer coefficient. This not only significantly increases the fullerene solubility but also effectively shortens the extraction time. Finally, the temperature-dependent solubility characteristics of fullerene in the ionic liquid enable efficient extraction. This invention employs a synergistic enhancement technology of ionic liquid and ultrasonic cavitation combined with a gradient temperature-controlled staged extraction strategy, achieving a total fullerene product extraction rate >80% and extracting C with a purity >98%. 70 Fullerenes, C with a purity >99% 60 Fullerenes are obtained, and energy consumption is reduced, significantly lowering processing costs. This invention introduces ionic liquids (new substances) and ultrasonic fields (new fields) based on matter-field analysis. Through resource analysis and utilizing temperature gradients, self-organized separation is achieved, successfully realizing the resource recovery and utilization of acetylene black conductive agent waste coke.

[0009] This method utilizes imidazole-based ionic liquids, which possess high affinity for fullerenes (solubility three times that of toluene) and are highly stable, as a green extractant, fundamentally avoiding the environmental and health hazards associated with traditional organic solvents. It effectively solves the safety risks and environmental pollution problems inherent in existing fullerene extraction methods. By introducing an ultrasonic cavitation field, the microjets and shock waves generated by the cavitation effect strongly disrupt the aggregated structure of carbon particles in the acetylene black conductive agent, greatly enhancing the mass transfer process and shortening the extraction time. Simultaneously, based on the temperature-dependent differences in the solubility of fullerene homologues in ionic liquids, a self-organized separation strategy of "high-temperature dissolution-gradient cooling crystallization" was designed, achieving C1 crystallization without the need for complex chromatographic equipment. 70 Fullerenes and C 60 Highly efficient fractionation and purification of fullerenes and oligomers. The extremely low vapor pressure of the final ionic liquid allows for efficient recovery and recycling via simple vacuum distillation, significantly reducing solvent consumption and waste emissions. This effectively solves the problems of cumbersome separation and purification steps, high energy consumption, and long production cycles in existing fullerene extraction methods.

[0010] Preferably, the heat treatment temperature is 400~500℃ and the time is 30~50min.

[0011] Preferably, the heat treatment is carried out in an inert atmosphere.

[0012] Preferably, the heat treatment is performed by programmed heating, and the heating rate of the programmed heating is 10~15℃ / min.

[0013] Preferably, step S1 specifically includes: uniformly spreading the acetylene black conductive agent waste coke in a reaction boat, placing the reaction boat in a tubular furnace, then introducing inert gas and heating to a preset temperature, maintaining the temperature for a preset time to achieve heat treatment of the acetylene black conductive agent waste coke, causing partial vaporization of impurities. After the temperature treatment is completed, heating is stopped, and the furnace is allowed to cool naturally while continuously purging nitrogen. The reaction boat is then removed, yielding the pretreated acetylene black conductive agent waste coke, which is then transferred to a dry, sealed container for storage and later use.

[0014] Preferably, the furnace body is allowed to cool naturally to 25~80°C.

[0015] Preferably, the inert gas is nitrogen.

[0016] Preferably, the preset temperature is 400~500℃ and the preset time is 30~50min.

[0017] Preferably, during the isothermal period, the inert gas flow rate is adjusted to 100-200 mL / min to maintain an inert atmosphere and carry away gaseous pyrolysis products.

[0018] Preferably, the imidazole ionic liquid is selected from 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]).

[0019] Preferably, the solid-liquid ratio of the acetylene black conductive agent waste coke to the imidazole ionic liquid is 1g:8~10mL.

[0020] Preferably, the frequency of the ultrasound is 40~50kHz.

[0021] Preferably, the power of the ultrasound is 300~500W.

[0022] Preferably, the ultrasound is in pulse mode, with the ultrasound on-time being 5-7 seconds and the ultrasound off-time being 2 seconds within each pulse cycle.

[0023] Preferably, the temperature of the ultrasonic extraction process is 30~40℃.

[0024] Preferably, the ultrasonic extraction process takes 10-20 minutes.

[0025] Preferably, step S2 includes: using an imidazole ionic liquid [BMIM][PF6] as the extractant, simultaneously applying an ultrasonic field to generate a cavitation effect, and using microjets to impact and break down carbon black aggregates, resulting in an ionic liquid extract rich in fullerenes and residual solid residue after extraction.

[0026] Preferably, step S2 includes: using an imidazole ionic liquid [BMIM][PF6] as the extractant and adding it together with the pretreated acetylene black conductive agent into a 3L jacketed glass reactor, equipped with a mechanical stirrer, a thermometer sleeve, and a reflux condenser (to prevent trace amounts of ionic liquid from evaporating), while simultaneously applying an ultrasonic field to generate cavitation effect, and micro-jet impact to break down carbon black agglomerates, resulting in an ionic liquid extract rich in fullerenes and residual solid residue after extraction.

[0027] Preferably, during the ultrasonic extraction process, the mechanical stirring speed is 200~300 rpm.

[0028] Preferably, the ultrasound is performed using a probe-type ultrasonic processor in pulse mode. The micro-jet impact breaks down the carbon black agglomerates, and the extraction yields an ionic liquid extract rich in fullerenes and residual solid residue.

[0029] Preferably, after ultrasonic extraction, the reaction mixture is subjected to vacuum filtration using a Buchner funnel and a 0.45 μm polytetrafluoroethylene (PTFE) filter membrane to separate the fullerene-rich ionic liquid extract from the residual solid residue. The solid residue is washed with a small amount of ionic liquid, and the resulting washings are combined with the fullerene-rich ionic liquid extract.

[0030] Preferably, the solid residue is washed 1 to 2 times.

[0031] Preferably, step S3 includes: heating the fullerene-rich ionic liquid extract to a first preset temperature, and then cooling it to a second preset temperature to selectively crystallize and precipitate C. 70 Fullerenes were then cooled further to a third preset temperature to selectively crystallize and precipitate C. 60 Fullerenes, yielding C 70 Fullerenes and C 60 Fullerenes.

[0032] Preferably, the first preset temperature is 55~60℃, the second preset temperature is 35~45℃, and the third preset temperature is 20~30℃.

[0033] Preferably, the first preset temperature is 60°C, the second preset temperature is 40°C, and the third preset temperature is 25°C.

[0034] Preferably, the heating method for raising the temperature to the first preset temperature is programmed heating, the heating rate for raising the temperature to the first preset temperature is 2~3℃ / min, and the temperature is kept constant for 30~40min after raising the temperature to the first preset temperature.

[0035] Preferably, the cooling method for cooling to the second preset temperature is programmed cooling, the cooling rate for cooling to the second preset temperature is 0.5~0.7℃ / min, and the temperature is kept constant for 100~120min after cooling to the second preset temperature; Preferably, the cooling method for continuing to cool down to the third preset temperature is programmed cooling, the cooling rate for continuing to cool down to the third preset temperature is 0.2~0.4℃ / min, and the temperature is kept constant for 180~200min after continuing to cool down to the third preset temperature.

[0036] Preferably, C is added during the cooling process to the second preset temperature. 70 Fullerene seed crystals, added to the C 70 The temperature for fullerene seeding is 48~52℃, and the C 70 The amount of fullerene seed crystals added is equal to the amount of fullerene (including C464) added. 70 Fullerenes and C 60 (0.1-0.2% of the theoretical mass of fullerene).

[0037] By adding a trace amount of high-purity C during the first stage of cooling crystallization (i.e., when supersaturation begins to build but spontaneous nucleation has not yet occurred). 70 Fullerene seed crystals guide the crystallization process to promote directional crystal growth, resulting in larger, more uniform crystals and improved product purity.

[0038] Preferably, C is added during the process of continuing to cool down to the third preset temperature. 60 Fullerene seed crystals, added to the C 60 The seeding temperature for fullerenes is 30~32℃, and the C 60 The amount of fullerene seed crystals added is equal to the amount of fullerene (including C464) added. 70 Fullerenes and C 60 (0.1-0.2% of the theoretical mass of fullerene).

[0039] By adding trace amounts of high-purity C during the second-stage cooling crystallization process 60 Fullerene seed crystals guide the crystallization process to promote directional crystal growth, resulting in larger, more uniform crystals and improved product purity.

[0040] Preferably, step S3 further includes: using n-hexane at a temperature of 40°C to treat the crystallized C 70 Fullerene was washed 2-3 times to obtain C 70 Fullerene crystals and washing solution.

[0041] Preferably, step S3 further includes: using n-hexane at a temperature of 40°C to treat the crystallized C 60 Fullerene was washed 2-3 times to obtain C 60 Fullerene crystals and washing solution.

[0042] Preferably, S3 includes: an initial heating stage, a first cooling crystallization stage, and a second cooling crystallization stage; In the initial heating stage, the extract is transferred to a crystallization vessel equipped with a jacket, precise temperature control, and a stirrer. Gentle stirring is initiated, and the temperature is raised to 60°C and maintained at this temperature to ensure that all the tiny crystal nuclei formed at the extraction temperature are completely dissolved, creating a clear starting point for controlled crystallization. In the first cooling crystallization stage, the entire process is stirred, and the temperature is reduced from 60°C to 40°C. This temperature is then maintained, and C is selectively precipitated. 70 After the fullerene crystals have been heated to the desired temperature, stop stirring and let stand for 5-8 minutes; then discharge the upper mother liquor (containing most of C) through the bottom discharge valve. 60 Fullerenes and oligomers were carefully transferred to another container for temporary storage. The remaining slurry (mainly C) 70 The fullerene crystals and a small amount of mother liquor were filtered. C 70 Fullerene crystals were washed with n-hexane at 40°C, with the washing solution volume approximately twice the crystal volume each time. 70 Fullerene crystals are washed 2-3 times, and the C after washing 70 Fullerene crystals were transferred to a vacuum drying oven; In the second cooling crystallization stage, the mother liquor separated in the first stage is reheated to 40°C and held at that temperature for 10 minutes with stirring throughout the process. Then, the temperature is lowered from 40°C to 25°C and held for 180-200 minutes. After the holding period, the mixture is filtered, and the crystals are washed 2-3 times with n-hexane. The resulting product is C10. 60 Fullerene crystals are collected from the remaining mother liquor for the recovery of ionic liquids.

[0043] Preferably, the stirring speed during the initial heating stage is 50-60 rpm, the stirring speed during the first cooling crystallization stage is 80-100 rpm, and the stirring speed during the second cooling crystallization stage is 100-120 rpm.

[0044] Preferably, step S3 further includes: collecting the remaining liquid after crystallization and performing vacuum heating distillation on the remaining liquid to recover the imidazole ionic liquid and achieve recycling.

[0045] Preferably, step S3 further includes: collecting the residual liquid after crystallization and the washing liquid and mixing them to obtain a mixed liquid; then using a rotary evaporator at a temperature of 50°C and atmospheric pressure to evaporate most of the n-hexane to obtain a rotary evaporation residue; then adding the rotary evaporation residue to a vacuum distillation flask, turning on the vacuum system, controlling the vacuum system pressure to 5~10 kPa, and heating to 100~120°C for vacuum distillation for 120~180 min, the residue remaining at the bottom of the distillation flask is the recovered imidazole ionic liquid [BMIM][PF6]; the recovered imidazole ionic liquid [BMIM][PF6] is taken out, cooled to room temperature, and can be recycled.

[0046] Preferably, the composition of the acetylene black conductive agent waste coke, by mass percentage, includes: iron (Fe) 1.2 ppm, nickel (Ni) 0.03 ppm, chromium (Cr) 0.2 ppm, manganese (Mn) 0.01 ppm, phosphorus (P) 0.7 ppm, yttrium (Y) 0.7 ppm, ash 0.01%, and the remainder being carbon; the carbon contains fullerene (C 60 +C 70 The mass percentage of ) is 1.83%; Preferably, the C in the acetylene black conductive agent waste coke 70 Fullerenes and C 60 The total extraction rate of fullerenes is greater than 90%; Preferably, the obtained C 70 The purity of fullerenes is greater than 98%; Preferably, the obtained C 60 The purity of fullerene is greater than 99%.

[0047] The method for extracting fullerenes from acetylene black conductive agent waste coke of the present invention includes a pretreatment stage, an extraction stage, a fractionation and separation stage, and a solvent recovery stage.

[0048] The pretreatment stage involves heat-treating the acetylene black conductive agent waste coke for 30 minutes under a nitrogen atmosphere and at a temperature of 400-500℃. Utilizing the difference in thermal stability between fullerenes and amorphous carbon (TRIZ separation principle), some impurities are vaporized, increasing the fullerene content from <1% to 2-3%. 60 Fullerenes and C 70 Fullerenes have relatively high thermal decomposition temperatures, especially under an inert atmosphere (nitrogen), where their molecular skeleton remains relatively stable. Amorphous carbon belongs to the transition state of carbon, with an internal structure similar to the layered structure of graphite, but arranged in an extremely disordered and irregular manner, containing a large number of sp^2 and sp^3 hybrid carbon atoms. This amorphous structure makes some of its internal carbon-hydrogen bonds or oligomer chains (such as diacetylene C4H2 and triacetylene C6H2) more prone to cracking or vaporization at high temperatures. By controlling the temperature, the negatively impacting parts of the system (impurities, residual oligomers) can be extracted from the whole, leaving a pure fullerene skeleton. Simultaneously, during the high-temperature treatment of acetylene black conductive agent waste char, the cracking or structural loosening of some amorphous carbon further exposes the fullerene molecules, making them more easily captured by subsequent extractants.

[0049] Extraction stage: Imidazole-based ionic liquid [BMIM][PF6] (melting point 10℃) was used as the extractant, which has a solubility of 8~12 mg / mL for fullerenes (3 times that of toluene). Simultaneously, a 40kHz / 300W ultrasonic field was applied to generate cavitation, and the microjets impacted and broke down carbon black aggregates, increasing the mass transfer coefficient by 5~8 times and shortening the extraction time to 15 minutes. Ionic liquids are non-volatile, non-flammable, and easily recyclable, making them a good alternative to traditional organic solvents.

[0050] The technical principle of using imidazole ionic liquid [BMIM][PF6] (melting point 10℃) as an extractant is as follows: First, the cation of the imidazole ionic liquid [BMIM]... + It possesses a large-area aromatic conjugated ring structure, which enables it to interact with fullerenes (C464- ... 60 / C 70 The π-electron clouds of the fullerenes form effective π-π interactions. This non-covalent interaction significantly reduces the lattice energy of the fullerenes in the solvent, disrupting the strong π-π stacking between fullerenes, thereby significantly improving their solubility. Secondly, [BMIM][PF6] is a hydrophobic ionic liquid, and its anion PF6... -This enhances the overall nonpolar characteristics. As a typical hydrophobic molecule, fullerenes have a good "affinity" with this hydrophobic solvent environment, which is beneficial for the uniform dispersion of their molecular structure in the solvent.

[0051] Under ultrasonic power of 40 kHz / 300W, a large number of microbubbles are generated in the solvent system. These bubbles release high-pressure shock waves and high-speed microjets upon instantaneous collapse (cavitation). The impact energy of these microjets is sufficient to break down the aggregate structure on and within the carbon black surface, dispersing the originally tightly bound carbon black particles into smaller monomers or small aggregates. Simultaneously, the destruction of the carbon black aggregates significantly increases the exposed specific surface area. This "physical tearing" effect exposes the previously obscured fullerene molecules to the solvent interface, greatly enhancing the contact opportunities between fullerenes and ionic liquids.

[0052] By combining the chemical dissolution properties of ionic liquids with the physical disruption effect of ultrasonic fields, a dual enhancement mechanism of "chemical dissolution + physical disruption" is formed. The high solubility and hydrophobicity of ionic liquids, along with the efficient interfacial impact from ultrasonic cavitation, significantly increase the rate of fullerene molecule transfer from the solid to the liquid phase (i.e., the mass transfer coefficient). Through this synergistic mechanism, the entire extraction process is greatly accelerated, reducing the extraction time to only 15 minutes. This not only improves production efficiency but also significantly reduces energy consumption.

[0053] Fractional separation stage: Utilizing the temperature-dependent solubility characteristics of fullerenes in ionic liquids, C is sequentially precipitated through a cooling crystallization process of 60℃→40℃→25℃. 70 Fullerene (purity >98%), C 60 Fullerenes (purity >99%) are used to achieve component separation.

[0054] In the ionic liquid [BMIM][PF6], the solubility of fullerenes exhibits a typical temperature-inverse behavior, meaning that solubility decreases as temperature decreases. As the temperature drops from 60°C to 25°C, the molecular kinetic energy of fullerenes decreases, the solvation effect of the solvent on the fullerene molecules weakens, leading to a dominance of van der Waals forces between fullerene molecules, and consequently, crystal precipitation. Furthermore, [BMIM][PF6] possesses strong polarity and high viscosity, and its hydrophobic alkyl chain (C8H...)... 17 The hydrophobic structure of the fullerene is matched, providing a high solubility benchmark, making temperature control the only means of regulation.

[0055] C precipitates at 60℃→40℃ 70 Fullerenes: At high temperatures (60°C), C in solution 70 Fullerenes have the highest solubility, C 60 Fullerenes are approaching their critical solubility. At this point, the temperature is lowered to 40°C, and C...70 The decrease in fullerene solubility promotes C 70 Fullerenes crystallize rapidly and precipitate, while C 60 Fullerenes remain in a dissolved state due to their relatively low solubility, preventing mixed crystallization.

[0056] C precipitates at 40℃→25℃ 60 Fullerenes: As the temperature continues to drop to 25°C, C 70 The solubility of fullerenes is already far below the equilibrium value at this temperature, C 70 After the fullerene crystals are separated, the remaining solution is mainly C. 60 Fullerenes. The temperature conditions at this point are just right for C. 60 Fullerenes precipitate from a saturated solution using C 60 The characteristic of further reduced solubility of fullerenes makes C 60 Fullerene crystals precipitate out with high crystallinity and a purity exceeding 99%.

[0057] Solvent recovery stage: The ionic liquid can be recovered and recycled by vacuum distillation at 120℃ / 5kPa for 2 hours. The extractant [BMIM][PF6] has a low vapor pressure and cannot be recovered by atmospheric distillation, but it has good thermal stability. By vacuum distillation, trace amounts of residual water, washing solvent (n-hexane), and possible pyrolysis light components can be completely removed under mild conditions far below its decomposition temperature (>400℃), restoring its pure state.

[0058] The beneficial effects of this invention are: This invention discloses a method for extracting fullerenes from acetylene black conductive agent waste coke. First, the acetylene black conductive agent waste coke is heat-treated. Utilizing the difference in thermal stability between fullerenes and amorphous carbon (TRIZ separation principle), impurities are partially vaporized, increasing the fullerene content to 2-3%. Second, an imidazole-based ionic liquid with a fullerene solubility of 8-12 mg / mL (three times that of toluene) is used as the extractant. Simultaneously, an ultrasonic field is applied to generate cavitation, and microjets impact and break down carbon black aggregates, increasing the mass transfer coefficient. This not only significantly improves the fullerene solubility but also effectively shortens the extraction time. Finally, the temperature-dependent solubility characteristics of fullerenes in the ionic liquid are utilized to achieve efficient extraction. This invention employs a synergistic enhancement technology of ionic liquid and ultrasonic cavitation combined with a gradient temperature-controlled staged extraction strategy, achieving a total fullerene product extraction rate >80% and extracting C with a purity >98%. 70 Fullerenes, C with a purity >99% 60Fullerenes are extracted, and energy consumption and processing costs are significantly reduced. This invention introduces ionic liquids (new substances) and ultrasonic fields (new fields) based on matter-field analysis. Through resource analysis and utilizing temperature gradients, self-organized separation is achieved, successfully realizing the resource recovery and utilization of acetylene black conductive agent waste coke. This method has significant application value in the field of nano-carbon material separation and purification technology. Attached Figure Description

[0059] Figure 1 C obtained in Example 1 60 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 2 C obtained in Example 1 70 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 3 C obtained in Example 2 60 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 4 C obtained in Example 2 70 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 5 C obtained in Example 3 60 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 6 C obtained in Example 3 70 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 7 C prepared in Comparative Example 1 60 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 8 C prepared in Comparative Example 1 70 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 9 C prepared in Comparative Example 2 60 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 10 C prepared in Comparative Example 2 70 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 11 C prepared in Comparative Example 3 60 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 12The C prepared in Comparative Example 4 70 The chromatogram of the filtrate obtained from the fullerene crystals was obtained by HPLC analysis. Figure 13 C 60 Standard curve of fullerenes; Figure 14 C 70 Standard curve of fullerenes; Figure 15 The standard curve for [BMIM][PF6]; Figure 16 The chromatogram of the supernatant obtained from the fullerene crystals prepared in Example 1 was obtained by IC analysis. Figure 17 The chromatogram of the supernatant obtained from the fullerene crystals prepared in Example 2 is obtained by IC analysis. Figure 18 The chromatogram of the supernatant obtained from the fullerene crystals prepared in Example 3 was obtained by IC analysis. Figure 19 The chromatogram of the supernatant obtained from the fullerene crystals prepared in Comparative Example 1 is obtained by IC analysis. Figure 20 The chromatogram is obtained by IC analysis of the supernatant corresponding to the fullerene crystals prepared in Comparative Example 2. Detailed Implementation

[0060] The following description, with reference to preferred embodiments, illustrates the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are merely illustrative of the present invention and not intended to limit the scope of protection of the present invention.

[0061] Where specific techniques or conditions are not specified in the detailed embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0062] In the following examples and comparative examples, the composition of the acetylene black conductive agent waste coke used, by mass percentage, included: iron (Fe) 1.2 ppm, nickel (Ni) 0.03 ppm, chromium (Cr) 0.2 ppm, manganese (Mn) 0.01 ppm, phosphorus (P) 0.7 ppm, yttrium (Y) 0.7 ppm, ash 0.01%, with the remainder being carbon; the carbon contained fullerene (C 60 +C 70The mass percentage of ) is 1.83%.

[0063] Example 1 A method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Weigh 100g of acetylene black conductive agent waste coke and spread it evenly in a porcelain crucible-type reaction boat. Place the reaction boat in a tube furnace and program the temperature to 400℃ in a nitrogen atmosphere at a heating rate of 10℃ / min. Then, maintain the temperature for 30min in an inert atmosphere with a nitrogen flow rate of 100mL / min to allow some of the impurities to vaporize. After the temperature is maintained, stop heating and allow the mixture to cool naturally to 50℃ while continuously purging with nitrogen. Remove the reaction boat to obtain the pretreated acetylene black conductive agent waste coke. S2. The pretreated acetylene black conductive agent waste char obtained in S1 and 850 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid were added to a 3 L jacketed glass reactor. The mechanical stirring speed was turned on at 200 rpm. A probe-type ultrasonic processor was used, with the ultrasonic frequency set to 40 kHz and the ultrasonic power set to 300 W. The ultrasonic on-time was 5 s and the ultrasonic off-time was 2 s in each pulse cycle. The ultrasonic extraction was carried out at 30 °C for 10 min. After extraction, the reaction mixture was filtered under reduced pressure using a Buchner funnel and a 0.45 μm polytetrafluoroethylene (PTFE) filter membrane to separate the fullerene-rich ionic liquid extract and the residual solid residue. The solid residue was washed once with a small amount of ionic liquid, and the washing liquid was combined with the fullerene-rich ionic liquid extract. S3. Transfer the fullerene-rich ionic liquid extract obtained in S2 to a crystallization vessel, start gentle stirring, and sequentially precipitate C through an initial heating stage (60°C), a first cooling crystallization stage, and a second cooling crystallization stage. 70 Fullerenes and C 60 Fullerenes; Specifically, it includes: S31. Initial heating stage: Turn on the stirrer and set the stirring speed to 55 rpm. Use a heating rate of 2℃ / min to program the temperature to 60℃ and keep it at 60℃ for 30 min. S32, First cooling crystallization stage: Adjust the stirring speed of the stirrer to 80 rpm, and perform programmed cooling at a cooling rate of 0.5℃ / min. When the temperature drops to 48℃, add 2μg C. 70Fullerene seed crystals were prepared, and then the temperature was further reduced to 40°C and maintained at 40°C for 100 minutes. After the holding time was completed, stirring was stopped, and the mixture was allowed to stand for 5 minutes. The upper mother liquor was carefully transferred to another container for temporary storage through the bottom discharge valve to obtain the first-stage mother liquor. The remaining slurry was filtered to obtain crystals and the remaining liquid from the first stage. The crystals were washed twice with n-hexane at 40°C to obtain washed C64. 70 Fullerene crystals and the first-stage washing solution, C after washing 70 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 70 Fullerene crystals; S33, Second Cooling Crystallization Stage: Transfer the first-stage mother liquor obtained from the first-stage filtration back to the crystallization vessel, heat to 40℃ and hold for 10 min, turn on the stirrer at 100 rpm, and perform programmed cooling at a cooling rate of 0.2℃ / min. When the temperature drops to 30℃, add 2 μg of C. 60 Fullerene seed crystals were prepared, and then the temperature was further reduced to 25°C and maintained at 25°C for 180 min. After the holding time, the crystals and the remaining liquid from the second stage were obtained by filtration. The crystals were washed twice with n-hexane at room temperature to obtain the washed C40. 60 Fullerene crystals and the second-stage washing solution, C after washing 60 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 60 Fullerene crystals; S4. The first-stage residual liquid and the first-stage washing liquid obtained in S32, and the second-stage residual liquid and the second-stage washing liquid obtained in S33 are mixed to obtain a mixture. Then, the mixture is rotary evaporated at 50°C and atmospheric pressure to remove most of the n-hexane, and the rotary evaporated residual liquid is obtained. The rotary evaporated residual liquid is transferred to a vacuum distillation flask, and vacuum distillation is carried out for 140 min under the conditions of controlling the vacuum system pressure to 6 kPa and heating temperature to 100°C. The distillation residue is the recovered imidazole ionic liquid [BMIM][PF6]. The recovered imidazole ionic liquid [BMIM][PF6] is taken out, cooled to room temperature, and then recycled.

[0064] Example 2 A method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Weigh 100g of acetylene black conductive agent waste coke and spread it evenly in a porcelain crucible-type reaction boat. Place the reaction boat in a tube furnace and program the temperature to 450℃ in a nitrogen atmosphere at a heating rate of 12℃ / min. Then, maintain the temperature for 40min in an inert atmosphere with a nitrogen flow rate of 150mL / min to allow some of the impurities to vaporize. After the temperature is maintained, stop heating and allow the mixture to cool naturally to 40℃ while continuously purging with nitrogen. Remove the reaction boat to obtain the pretreated acetylene black conductive agent waste coke. S2. The pretreated acetylene black conductive agent waste char obtained in S1 was added together with 900 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid into a 3 L jacketed glass reactor. The mechanical stirring speed was turned on at 250 rpm. A probe-type ultrasonic processor was used, with the ultrasonic frequency set to 45 kHz and the ultrasonic power set to 400 W. The ultrasonic on-time was 6 s and the ultrasonic off-time was 2 s in each pulse cycle. The ultrasonic extraction was carried out at 35 °C for 15 min. After extraction, the reaction mixture was filtered under reduced pressure using a Buchner funnel and a 0.45 μm polytetrafluoroethylene (PTFE) filter membrane to separate the fullerene-rich ionic liquid extract and the residual solid residue. The solid residue was washed once with a small amount of ionic liquid, and the washing liquid was combined with the fullerene-rich ionic liquid extract. S3. Transfer the fullerene-rich ionic liquid extract obtained in S2 to a crystallization vessel, start gentle stirring, and sequentially precipitate C through an initial heating stage (60°C), a first cooling crystallization stage, and a second cooling crystallization stage. 70 Fullerenes and C 60 Fullerenes; Specifically, it includes: S31. Initial heating stage: Turn on the stirrer and set the stirring speed to 55 rpm. Use a heating rate of 2℃ / min to program the temperature up to 60℃ and keep it at 60℃ for 35 min. S32, First cooling crystallization stage: Adjust the stirring speed of the stirrer to 90 rpm, and perform programmed cooling at a cooling rate of 0.6℃ / min. When the temperature drops to 50℃, add 2μg C. 70 Fullerene seed crystals were prepared, and then the temperature was further reduced to 40°C and maintained at 40°C for 110 minutes. After the holding time was completed, stirring was stopped, and the mixture was allowed to stand for 6 minutes. The upper mother liquor was carefully transferred to another container for temporary storage through the bottom discharge valve to obtain the first-stage mother liquor. The remaining slurry was filtered to obtain crystals and the remaining liquid from the first stage. The crystals were washed twice with n-hexane at 40°C to obtain washed C64. 70 Fullerene crystals and the first-stage washing solution, C after washing 70 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C70 Fullerene crystals; S33, Second Cooling Crystallization Stage: Transfer the first-stage mother liquor obtained from the first-stage filtration back to the crystallization vessel, heat to 40℃ and hold for 10 min, turn on the stirrer at 110 rpm, and perform programmed cooling at a cooling rate of 0.3℃ / min. When the temperature drops to 30℃, add 2 μg of C. 60 Fullerene seed crystals were prepared, and then the temperature was further reduced to 25°C and maintained at 25°C for 190 min. After the holding time, the crystals and the remaining liquid from the second stage were obtained by filtration. The crystals were washed twice with n-hexane at room temperature to obtain the washed C40. 60 Fullerene crystals and the second-stage washing solution, C after washing 60 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 60 Fullerene crystals; S4. The first-stage residual liquid and the first-stage washing liquid obtained in S32, and the second-stage residual liquid and the second-stage washing liquid obtained in S33 are mixed to obtain a mixture. Then, the mixture is rotary evaporated at 50°C and atmospheric pressure to remove most of the n-hexane, and the rotary evaporated residual liquid is obtained. The rotary evaporated residual liquid is transferred to a vacuum distillation flask, and vacuum distillation is carried out for 160 min under the conditions of controlling the vacuum system pressure to 8 kPa and heating temperature to 110°C. The distillation residue is the recovered imidazole ionic liquid [BMIM][PF6]. The recovered imidazole ionic liquid [BMIM][PF6] is taken out, cooled to room temperature, and then recycled.

[0065] Example 3 A method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Weigh 100g of acetylene black conductive agent waste coke and spread it evenly in a porcelain crucible-type reaction boat. Place the reaction boat in a tube furnace and program the temperature to 450℃ in a nitrogen atmosphere at a heating rate of 15℃ / min. Then, maintain the temperature for 50min in an inert atmosphere with a nitrogen flow rate of 200mL / min to allow some of the impurities to vaporize. After the temperature is maintained, stop heating and allow the mixture to cool naturally to 40℃ while continuously purging with nitrogen. Remove the reaction boat to obtain the pretreated acetylene black conductive agent waste coke. S2. The pretreated acetylene black conductive agent waste char obtained in S1 was added together with 950 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid into a 3 L jacketed glass reactor. The mechanical stirring speed was turned on at 300 rpm. A probe-type ultrasonic processor was used, with the ultrasonic frequency set to 50 kHz and the ultrasonic power set to 500 W. The ultrasonic on-time was 7 s and the ultrasonic off-time was 2 s in each pulse cycle. The ultrasonic extraction was carried out at 40 °C for 20 min. After the extraction was completed, the reaction mixture was filtered under reduced pressure using a Buchner funnel and a 0.45 μm polytetrafluoroethylene (PTFE) filter membrane to separate the fullerene-rich ionic liquid extract and the residual solid residue. The solid residue was washed twice with a small amount of ionic liquid, and the washing liquid was combined with the fullerene-rich ionic liquid extract. S3. Transfer the fullerene-rich ionic liquid extract obtained in S2 to a crystallization vessel, start gentle stirring, and sequentially precipitate C through an initial heating stage (60°C), a first cooling crystallization stage, and a second cooling crystallization stage. 70 Fullerenes and C 60 Fullerenes; Specifically, it includes: S31. Initial heating stage: Turn on the stirrer and set the stirring speed to 55 rpm. Use a heating rate of 3℃ / min to program the temperature up to 60℃ and keep it at 60℃ for 40 min. S32, First cooling crystallization stage: Adjust the stirring speed of the stirrer to 100 rpm, and perform programmed cooling at a cooling rate of 0.7℃ / min. When the temperature drops to 52℃, add 3.5μg C. 70 Fullerene seed crystals were prepared, and then the temperature was further reduced to 40°C and maintained at 40°C for 120 minutes. After the holding time was completed, stirring was stopped, and the mixture was allowed to stand for 8 minutes. The upper mother liquor was carefully transferred to another container for temporary storage through the bottom discharge valve to obtain the first-stage mother liquor. The remaining slurry was filtered to obtain crystals and the remaining liquid from the first stage. The crystals were washed twice with n-hexane at 40°C to obtain washed C64. 70 Fullerene crystals and the first-stage washing solution, C after washing 70 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 70 Fullerene crystals; S33, Second Cooling Crystallization Stage: The mother liquor obtained from the first stage filtration is transferred back to the crystallization vessel, heated to 40℃ and held for 10 min. The stirrer is turned on at a speed of 120 rpm, and the temperature is programmed to decrease at a rate of 0.4℃ / min. When the temperature drops to 32℃, 3.5 μg of C is added. 60Fullerene seed crystals were prepared, and then the temperature was further reduced to 25°C and maintained at 25°C for 200 min. After the holding time, the crystals and the remaining liquid from the second stage were obtained by filtration. The crystals were washed three times with n-hexane to obtain the washed C40. 60 Fullerene crystals and the second-stage washing solution, C after washing 60 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 60 Fullerene crystals; S4. The first-stage residual liquid and the first-stage washing liquid obtained in S32, and the second-stage residual liquid and the second-stage washing liquid obtained in S33 are mixed to obtain a mixture. Then, the mixture is rotary evaporated at 50°C and atmospheric pressure to remove most of the n-hexane, and the rotary evaporated residual liquid is obtained. The rotary evaporated residual liquid is transferred to a vacuum distillation flask, and vacuum distillation is carried out for 180 min under the conditions of controlling the vacuum system pressure at 10 kPa and heating temperature at 120°C. The distillation residue is the recovered imidazole ionic liquid [BMIM][PF6]. The recovered imidazole ionic liquid [BMIM][PF6] is taken out, cooled to room temperature, and then recycled.

[0066] Comparative Example 1 A method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Weigh 100 g of acetylene black conductive agent waste coke and 950 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid and add them together to a 3 L jacketed glass reactor. Turn on the mechanical stirring speed of 300 rpm, use a probe-type ultrasonic processor, set the ultrasonic frequency to 50 kHz, the ultrasonic power to 500 W, and use a pulse mode with an ultrasonic on time of 7 s and an ultrasonic off time of 2 s in each pulse cycle. Stir and ultrasonically extract for 20 min at a temperature of 40 °C. After extraction, filter the reaction mixture under reduced pressure using a Buchner funnel and a 0.45 μm polytetrafluoroethylene (PTFE) filter membrane to separate the fullerene-rich ionic liquid extract and the remaining solid residue. Wash the solid residue twice with a small amount of ionic liquid, and combine the washing liquid with the fullerene-containing ionic liquid extract. S2. Transfer the ionic liquid extract containing fullerene obtained in S1 to a crystallization vessel, start gentle stirring, and sequentially precipitate C through an initial heating stage (60℃), a first cooling crystallization stage, and a second cooling crystallization stage. 70 Fullerenes and C 60 Fullerenes; Specifically, it includes: S21. Initial heating stage: Turn on the stirrer and set the stirring speed to 55 rpm. Use a heating rate of 3℃ / min to program the temperature up to 60℃ and keep it at 60℃ for 40 min. S22, First cooling crystallization stage: Adjust the stirring speed of the stirrer to 100 rpm, and perform programmed cooling at a cooling rate of 0.7℃ / min. When the temperature drops to 52℃, add 3.5μg C. 70 Fullerene seed crystals were prepared, and then the temperature was further reduced to 40°C and maintained at 40°C for 120 minutes. After the holding time was completed, stirring was stopped, and the mixture was allowed to stand for 8 minutes. The upper mother liquor was carefully transferred to another container for temporary storage through the bottom discharge valve to obtain the first-stage mother liquor. The remaining slurry was filtered to obtain crystals and the remaining liquid from the first stage. The crystals were washed twice with n-hexane at 40°C to obtain washed C64. 70 Fullerene crystals and the first-stage washing solution, C after washing 70 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 70 Fullerene crystals; S23, Second Cooling Crystallization Stage: The mother liquor obtained from the first stage filtration is transferred back to the crystallization vessel, heated to 40℃ and held for 10 min. The stirrer is turned on at a speed of 120 rpm, and the temperature is programmed to decrease at a rate of 0.4℃ / min. When the temperature drops to 32℃, 3.5 μg of C is added. 60 Fullerene seed crystals were prepared, and then the temperature was further reduced to 25°C and maintained at 25°C for 200 min. After the holding time, the crystals and the remaining liquid from the second stage were obtained by filtration. The crystals were washed three times with n-hexane to obtain the washed C40. 60 Fullerene crystals and the second-stage washing solution, C after washing 60 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 60 Fullerene crystals; S3. The first-stage residual liquid and the first-stage washing liquid obtained in S22, and the second-stage residual liquid and the second-stage washing liquid obtained in S23 are mixed to obtain a mixture. Then, the mixture is rotary evaporated at 50°C and atmospheric pressure to remove most of the n-hexane, and the rotary evaporated residual liquid is obtained. The rotary evaporated residual liquid is transferred to a vacuum distillation flask, and vacuum distillation is carried out for 180 min under the conditions of controlling the vacuum system pressure at 10 kPa and heating temperature at 120°C. The distillation residue is the recovered imidazole ionic liquid [BMIM][PF6]. The recovered imidazole ionic liquid [BMIM][PF6] is taken out, cooled to room temperature, and then recycled.

[0067] Comparative Example 2 A method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Weigh 100g of acetylene black conductive agent waste coke and spread it evenly in a porcelain crucible-type reaction boat. Place the reaction boat in a tube furnace and program the temperature to 500℃ in a nitrogen atmosphere at a heating rate of 15℃ / min. Then, maintain the temperature for 50min in an inert atmosphere with a nitrogen flow rate of 200mL / min to allow some of the impurities to vaporize. After the temperature is maintained, stop heating and allow the mixture to cool naturally to 40℃ while continuously purging with nitrogen. Remove the reaction boat to obtain the pretreated acetylene black conductive agent waste coke. S2. The pretreated acetylene black conductive agent waste char obtained in S1 was added together with 950 mL of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid into a 3 L jacketed glass reactor. The mechanical stirring was turned on at 300 rpm and the mixture was stirred and extracted at 40 °C for 20 min. After extraction, the reaction mixture was filtered under reduced pressure using a Buchner funnel and a 0.45 μm polytetrafluoroethylene (PTFE) filter membrane to separate the ionic liquid extract containing fullerene and the remaining solid residue. The solid residue was washed twice with a small amount of ionic liquid, and the washing liquid was combined with the ionic liquid extract containing fullerene. S3. Transfer the ionic liquid extract containing fullerene obtained in S2 to a crystallization vessel, start gentle stirring, and sequentially precipitate C through an initial heating stage (60℃), a first cooling crystallization stage, and a second cooling crystallization stage. 70 Fullerenes and C 60 Fullerenes; Specifically, it includes: S31. Initial heating stage: Turn on the stirrer and set the stirring speed to 55 rpm. Use a heating rate of 3℃ / min to program the temperature up to 60℃ and keep it at 60℃ for 40 min. S32. First Cooling Crystallization Stage: Adjust the stirring speed of the stirrer to 100 rpm, and cool down to 40℃ at a cooling rate of 0.7℃ / min, maintaining a constant temperature of 40℃ for 120 minutes. After the holding period, stop stirring, let stand for 8 minutes, and carefully transfer the upper mother liquor to another container for temporary storage through the bottom discharge valve to obtain the first stage mother liquor. Filter the remaining slurry to obtain crystals and the remaining liquid from the first stage. Wash the crystals twice with n-hexane at 40℃ to obtain the washed C... 70 Fullerene crystals and the first-stage washing solution, C after washing 70 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 70 Fullerene crystals; S33. Second Cooling Crystallization Stage: The mother liquor obtained from the first stage filtration is transferred back to the crystallization vessel, heated to 40℃ and held for 10 min. The stirrer is turned on at a speed of 120 rpm, and the temperature is programmed to decrease to 25℃ at a cooling rate of 0.4℃ / min, and held at 25℃ for 200 min. After the holding period, the crystals and the remaining liquid from the second stage are obtained by filtration. The crystals are washed three times with n-hexane to obtain the washed C... 60 Fullerene crystals and the second-stage washing solution, C after washing 60 Fullerene crystals were transferred to a vacuum drying oven for vacuum drying to obtain C 60 Fullerene crystals; S4. The first-stage residual liquid and the first-stage washing liquid obtained in S32, and the second-stage residual liquid and the second-stage washing liquid obtained in S33 are mixed to obtain a mixture. Then, the mixture is rotary evaporated at 50°C and atmospheric pressure to remove most of the n-hexane, and the rotary evaporated residual liquid is obtained. The rotary evaporated residual liquid is transferred to a vacuum distillation flask, and vacuum distillation is carried out for 180 min under the conditions of controlling the vacuum system pressure at 10 kPa and heating temperature at 120°C. The distillation residue is the recovered imidazole ionic liquid [BMIM][PF6]. The recovered imidazole ionic liquid [BMIM][PF6] is taken out, cooled to room temperature, and then recycled.

[0068] Comparative Example 3 A conventional method for extracting fullerenes from acetylene black conductive agent waste coke includes the following steps: S1. Weigh 100g of acetylene black conductive agent waste coke and 1200ml of toluene solution and place them in a Soxhlet extractor. Reflux for 8 hours to dissolve fullerenes using the boiling reflux circulation of toluene. After extraction, centrifuge at 800rpm for 10min to remove insoluble coke residue and metal residues. Collect the clear toluene extract. S2. Transfer the toluene extract to a rotary evaporator and evaporate most of the toluene at 50°C and normal pressure; a light purple residue is obtained, which is a mixture of crude fullerenes (mainly containing C). 60 Fullerenes and C 70 Fullerenes); S3. Dissolve the crude fullerene mixture again in 50 mL of toluene solution to obtain a crude fullerene mixture. Then, pour the crude fullerene mixture into a column packed with activated carbon / silica gel. Separation is achieved by utilizing the differences in adsorption capacity of different fullerene molecules. The first eluting component is purple and is C. 60 Fullerenes; the second effluent component was reddish-brown and was C. 70 Fullerenes.

[0069] Detection and Analysis 1) C 60 Fullerenes and C 70 Determination of fullerene extraction yield The specific operating steps are as follows: (1) Sample preparation: Accurately weigh 100g of pretreated acetylene black conductive agent waste char (W1). At the same time, accurately measure the dried C obtained after one complete extraction-separation process. 60 Fullerene crystals and C 70 The total mass (W2) of the fullerene crystals, i.e., the C actually extracted from the acetylene black conductive agent in the examples and comparative examples. 60 Fullerene crystals and C 70 Total mass of fullerene crystals (W2).

[0070] (2) Content benchmark determination: It is necessary to know the accurate content of fullerene in W1. A benchmark is established by Soxhlet extraction-gravimetric method: Another batch of pretreated acetylene black conductive agent waste char from the same batch is subjected to Soxhlet extraction for 48 hours with sufficient toluene. The extract is evaporated by rotary evaporation and vacuum dried to constant weight. The mass of the obtained solid is the total mass of extractable fullerene in the pretreated acetylene black conductive agent waste char (W_ref). This value is used as the denominator benchmark for calculating the extraction rate.

[0071] (3) Extraction rate calculation formula (I): Extraction rate = (W2 / W_ref) × 100% (I) In formula (Ⅰ), W2 represents dried C 60 Fullerene crystals and C 70 The total mass of fullerene crystals, in g; W_ref represents the total mass of fullerenes that can be extracted from the pretreated acetylene black conductive agent waste coke, in g.

[0072] In Examples 1 to 3 and Comparative Examples 1 to 3, C 60 Fullerenes and C 70 The results of the fullerene extraction yield determination are shown in Table 1.

[0073] Table 1 shows C 60 Fullerenes and C 70 Calculation results of fullerene extraction yield As can be seen from the comparative analysis in Table 1, in Examples 1 to 3, fullerenes were extracted from acetylene black conductive agent waste coke using the synergistic effect of ionic liquid and ultrasonic cavitation, ultimately achieving the extraction of fullerenes (C14-C24-C24). 60 +C 70The overall extraction rate was >80%. In particular, Example 3 achieved an extraction rate as high as 86.5%, which is 11.3% and 13.0% higher than the extraction processes of Comparative Example 1 (75.2%) and Comparative Example 2 (73.5%), respectively. This demonstrates the superiority of the combined use of ionic liquid and ultrasonic cavitation in Examples 1-3. In contrast, the traditional toluene extraction process used in Comparative Example 3 only achieved an extraction rate of 70.3%, and also posed environmental pollution and safety hazards due to toluene volatilization.

[0074] 2) C 60 Fullerene crystals and C 70 Determination of the purity of fullerene crystal extraction The method for determining the purity of the extract is as follows: The purity of the extract was determined using high-performance liquid chromatography (HPLC), a widely accepted and used standard method. A reversed-phase C18 column (e.g., 4.6 mm × 250 mm, 5 μm) was used. Gradient elution with toluene / acetonitrile or isocratic elution was employed (e.g., toluene:acetonitrile = 80:20, v / v). A UV detector was used at a detection wavelength of 330 nm (characteristic absorption peak of fullerenes), and the flow rate was 1.0 mL / min.

[0075] The specific operating steps are as follows: (1) Sample pretreatment: Accurately weigh approximately 5 mg of dried C from Examples 1 to 3 and Comparative Examples 1 to 3. 60 Fullerene crystals and C 70 Fullerene crystal product sample. Dissolved in toluene and diluted to 10 mL in a volumetric flask (ultrasonic dissolution may be used if necessary) to obtain a sample solution. Filtered through a 0.22 μm PTFE syringe filter, the filtrate was used for HPLC analysis, and the C values ​​corresponding to Examples 1 to 3 and Comparative Examples 1 to 3 were analyzed. 60 Filtrate of fullerene crystals and C 70 The chromatograms obtained by HPLC analysis of the filtrate of fullerene crystals are as follows: Figures 1 to 12 As shown.

[0076] Figure 1 Example 1-C 60 C corresponding to the one prepared in Example 1 60 Fullerene crystal samples, Figure 2 Example 1-C 70 C corresponding to the one prepared in Example 1 70 Fullerene crystal samples, Figure 3 Example 2-C 60 C obtained in Example 2 60 Fullerene crystal samples, Figure 4 Example 2-C 70C obtained in Example 2 70 Fullerene crystal samples, Figure 5 Example 3-C 60 C obtained in Example 3 60 Fullerene crystal samples, Figure 6 Example 3-C 70 C obtained in Example 3 70 Fullerene crystal samples, Figure 7 Comparative Example 1-C 60 C prepared in response ratio 1 60 Fullerene crystal samples, Figure 8 Comparative Example 1-C 70 C prepared in response ratio 1 70 Fullerene crystal samples, Figure 9 Comparative Example 2-C 60 C prepared in response ratio 2 60 Fullerene crystal samples, Figure 10 Comparison 2-C 70 C prepared in response ratio 2 70 Fullerene crystal samples, Figure 11 Comparative Example 3-C 60 C corresponding to the preparation in Comparative Example 3 60 Fullerene crystal samples, Figure 12 Comparative Example 3-C 70 C prepared in response ratio 3 70 Fullerene crystal sample.

[0077] (2) Calibration standards and standard curve plotting: Purchase high-purity (>99.9%) C 60 Fullerenes and C 70 Fullerene standards. A series of C10 solutions at different concentrations (5 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 100 μg / mL) were precisely prepared using toluene. 60 Fullerenes and C 70 Fullerene standard solution. Inject and analyze separately, then perform linear regression of peak area (A) against concentration (C) to obtain C. 60 The standard curve of fullerenes is as follows Figure 13 C 60 The equation for the standard curve of fullerenes is shown in equation (II), yielding C. 70 The standard curve of fullerenes is as follows Figure 14 As shown, C 70 The equation for the standard curve of fullerenes is shown in equation (Ⅲ), and the correlation coefficient R is... 2 >0.999.

[0078] In equations (II) and (III), C_ C60 Indicates C in the standard solution 60 The concentration of fullerenes, in μg / mL; A_ C60 Indicates C in the chromatogram 60 Peak area corresponding to fullerene; C_ C70 Indicates C in the standard solution 70 The concentration of fullerenes, in μg / mL; A_ C70 Indicates C in the chromatogram 70 Peak area corresponding to fullerene.

[0079] (3) C 60 Fullerene crystals and C 70 The purity (mass fraction, w) of fullerene crystal extraction is calculated using the following formulas (IV) and (V): C 60 The purity of fullerene crystals is calculated as shown in formula (Ⅳ): In equation (Ⅳ), Purity _C60 C represents 60 Purity (%) of fullerene crystal sample; C _C60 This indicates the C in the sample solution calculated according to formula (II). 60 The concentration of fullerenes is expressed in μg / mL; V represents the final volume of the sample solution (10 mL); m _C60 Indicates the weighed C 60 Mass of the fullerene crystal product sample, in mg.

[0080] C 70 The purity of fullerene crystals is calculated using formula (V): In equation (V), Purity _C70 C represents 70 Purity (%) of fullerene crystal sample; C _C70 This indicates the C in the sample solution calculated according to formula (Ⅲ). 70 The concentration of fullerene is expressed in μg / mL; V represents the final volume of the sample solution (10 mL). m _C70 Indicates the weighed C 70 Mass of the fullerene crystal product sample, in mg.

[0081] 3) Determination of residual ionic liquid content The content of residual ionic liquids was determined using ion chromatography (IC), and the method is as follows: Standard curve preparation: Accurately weigh 100.0 mg of [BMIM][PF6] standard and place it in a 100 mL volumetric flask. Dissolve it in a methanol / water (50:50, v / v) mixture and dilute to the mark to obtain a 1000 ppm standard stock solution. Prepare standard solutions at concentrations of 0 ppm, 2 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm, and 100 ppm. Inject each solution separately for analysis, and perform linear regression of peak area (y) against concentration (x). Establish the calibration curve as follows: Figure 15 As shown, the equation of the standard curve of [BMIM][PF6] is given by equation (VI).

[0082] In equation (VI), x represents the concentration of [PF6] in the standard solution. - The concentration is expressed in μg / mL, and y represents [PF6] in the chromatogram. - The corresponding peak area.

[0083] (2) Sample pretreatment (for fullerene products): Weigh 100 mg of the dried fullerene (C) from Examples 1 to 3 and Comparative Examples 1 to 2 respectively. 60 Fullerenes and C 70 Take 50 mg of each fullerene sample. Add 10 mL of deionized water ([PF6]). - The ionic liquid is soluble, while fullerenes are insoluble. The mixture was sonicated for 10 minutes to dissolve the [BMIM][PF6] ionic liquid, which may be adsorbed onto the product surface, in deionized water. After centrifugation, the supernatant was collected and analyzed by IC. The chromatograms of the supernatants obtained from the sonication of fullerene crystals in Examples 1 to 3 and Comparative Examples 1 to 2 are shown in the following figures. Figures 16 to 20 As shown.

[0084] (3) Results: The residual amount (ppm) of [BMIM][PF6] in the fullerene product was calculated using formula (VII).

[0085] In equation (VII), This indicates that [PF6] is based on the chromatogram. - The concentration of [BMIM][PF6] in the supernatant was calculated using the corresponding peak area combined with formula (VI), in μg / mL. The supernatant volume is expressed in mL; D represents the dilution factor (D = 1 in this experiment). This indicates the mass of the fullerene sample weighed.

[0086] C 60 Fullerenes and C 70The extraction purity of fullerene and the content of residual ionic liquid are shown in Table 2.

[0087] Table 2 is for C 60 Fullerenes and C 70 Results of fullerene extraction purity and residual ionic liquid content As can be seen from Table 2, Examples 1 to 3, through the synergistic effect of ionic liquid and ultrasonic cavitation, extracted fullerenes from acetylene black conductive agent waste coke, ultimately achieving C... 60 Purity >99%, C 70 The purity was >98%, and the content of residual ionic liquid was less than 100 ppm (0.01%). The product from Example 3 had the highest purity. 60 Up to 99.9%, C 70 The efficiency reached 99.5%, higher than the processes used in Comparative Examples 1 and 2. This demonstrates the effectiveness of pretreatment of the acetylene black conductive agent waste coke raw material, the utilization of ultrasonic cavitation, and the introduction of C2C during the process. 60 Fullerene crystals and C 70 Fullerene crystals demonstrate superior performance in improving product purity. In contrast, the traditional toluene extraction process used in Comparative Example 3 yields fullerene products with a purity of only around 90%, and the toluene extractant used in this process is highly volatile, hindering secondary recycling. Compared to traditional processes, the lower vapor pressure of ionic liquids allows for efficient recovery and recycling through simple vacuum distillation, significantly reducing solvent consumption and waste emissions. These data further highlight the advantages of the technologies in Examples 1-3 in green chemistry and sustainable development.

[0088] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for extracting fullerenes from acetylene black conductive agent waste coke, characterized in that, Includes the following steps: S1. Heat treatment of acetylene black conductive agent waste coke to obtain pretreated acetylene black conductive agent waste coke; S2. Under ultrasonic conditions, imidazole ionic liquids were used as extractants to perform ultrasonic extraction on pretreated acetylene black conductive agent waste coke, and the resulting ionic liquid extract rich in fullerenes and solid residue were obtained. S3. The ionic liquid extract rich in fullerenes is subjected to a stepped cooling crystallization process to obtain C. 70 Fullerenes and C 60 Fullerenes.

2. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 1, characterized in that, The heat treatment temperature is 400~500℃, and the time is 30~50min; And / or, the heat treatment is performed in an inert atmosphere; And / or, the heating method of the heat treatment is programmed heating, and the heating rate of the programmed heating is 10~15℃ / min.

3. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 1, characterized in that, The imidazole ionic liquid is selected from 1-butyl-3-methylimidazolium hexafluorophosphate; And / or, the solid-liquid ratio of the acetylene black conductive agent waste coke to the imidazole ionic liquid is 1g:8~10mL.

4. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 1, characterized in that, The frequency of the ultrasound is 40~50kHz; And / or, the power of the ultrasound is 300~500W; And / or, the ultrasound adopts a pulse mode, with the ultrasound on-time being 5-7 seconds and the ultrasound off-time being 2 seconds within each pulse cycle; And / or, the temperature of the ultrasonic extraction treatment is 30~40℃; And / or, the ultrasonic extraction treatment time is 10~20 min.

5. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 1, characterized in that, S3 includes: heating the fullerene-rich ionic liquid extract to a first preset temperature, and then cooling it to a second preset temperature to selectively crystallize and precipitate C. 70 Fullerenes were then cooled further to a third preset temperature to selectively crystallize and precipitate C. 60 Fullerenes, yielding C 70 Fullerenes and C 60 Fullerenes.

6. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 5, characterized in that, The first preset temperature is 55~60℃, the second preset temperature is 35~45℃, and the third preset temperature is 20~30℃.

7. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 5, characterized in that, The heating method for raising the temperature to the first preset temperature is programmed heating, with a heating rate of 2~3℃ / min, and the temperature is kept constant for 30~40min after the temperature is raised to the first preset temperature. And / or, the cooling method for cooling to the second preset temperature is programmed cooling, the cooling rate for cooling to the second preset temperature is 0.5~0.7℃ / min, and the temperature is kept constant for 100~120min after cooling to the second preset temperature; And / or, the cooling method for continuing to cool down to the third preset temperature is programmed cooling, the cooling rate for continuing to cool down to the third preset temperature is 0.2~0.4℃ / min, and the temperature is kept constant for 180~200min after continuing to cool down to the third preset temperature.

8. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 5, characterized in that, C is added during the process of cooling down to the second preset temperature. 70 Fullerene seed crystals, added to the C 70 The temperature for fullerene seeding is 48~52℃, and the C 70 The amount of fullerene seed crystals added is 0.1% to 0.2% of the theoretical mass of the fullerene; And / or, during the process of continuing to cool down to the third preset temperature, C is added. 60 Fullerene seed crystals, added to the C 60 The seeding temperature for fullerenes is 30~32℃, and the C 60 The amount of fullerene seed crystals added is 0.1 to 0.2% of the theoretical mass of fullerene.

9. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 1, characterized in that, S3 further includes: collecting the remaining liquid after crystallization and performing vacuum heating distillation on the remaining liquid to recover imidazole ionic liquid and achieve recycling.

10. The method for extracting fullerenes from acetylene black conductive agent waste coke according to claim 1, characterized in that, The composition of the acetylene black conductive agent waste coke, by mass percentage, includes: iron 1.2 ppm, nickel 0.03 ppm, chromium 0.2 ppm, manganese 0.01 ppm, phosphorus 0.7 ppm, yttrium 0.7 ppm, ash 0.01%, with the remainder being carbon; the carbon contains 1.83% fullerene by mass. And / or, the C in the acetylene black conductive agent waste coke 70 Fullerenes and C 60 The total extraction rate of fullerenes is greater than 90%; And / or, the obtained C 70 The purity of fullerenes is greater than 98%; And / or, the obtained C 60 The purity of fullerene is greater than 99%.

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