Biomass waste and industrial waste salt co-processing method

Abstract

The invention belongs to the technical field of waste resource utilization, and particularly relates to a biomass waste and industrial waste salt co-processing method which comprises the following steps: S1, heating industrial waste salt to melt the industrial waste salt; s2, mixing biomass waste, a doping agent and molten industrial waste salt, and performing carbonization reaction to obtain a molten mixture; s3, pulping the molten mixture to obtain first slurry, adding a foaming agent, and performing flotation to obtain a carbon material and second slurry; s4, carrying out solid-liquid separation on the second slurry to obtain salt particles and salt liquid; the dopant includes a compound containing N and / or S. According to the co-processing method, the molten industrial waste salt serves as a heat source and a medium for carbonizing the biomass waste, meanwhile, harmless treatment of preparation of a carbon material from the biomass waste and the industrial waste salt is achieved, high-added-value utilization of the biomass waste is promoted, energy consumption is low, efficiency is high, and the overall cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of waste resource utilization, and specifically relates to a method for co-processing biomass waste and industrial waste salt. Background Art

[0002] In daily life and industrial and agricultural production, a large amount of biomass waste is generated, such as wood chips, peanut shells, rice husks, straw, etc. Some of these biomass wastes are used as feed, fuel, chemical raw materials, etc., but most of them will be directly incinerated or landfilled, resulting in a large amount of waste and causing environmental problems. A large amount of waste salt containing organic impurities is also generated in industrial production. The organic matter in these industrial waste salts is complex, including a variety of organic matter such as benzene, halogenated hydrocarbons, alcohols, acids, etc., which are difficult to remove efficiently and specifically. In the prior art, there is a method of heating industrial waste salt to above 800°C to melt it and remove the organic matter therein, and then undergoing steps such as recrystallization to obtain high-purity salt, but this method consumes a large amount of heating energy and water resources, has high energy consumption, and is cost-effective. Summary of the invention

[0003] Therefore, the present invention provides a method for the coordinated treatment of biomass waste and industrial waste salt, using molten industrial waste salt as a heat source and medium for carbonizing biomass waste, while achieving the preparation of carbon materials from biomass waste and harmless treatment of industrial waste salt. The obtained carbon materials can be used as battery negative electrode carbon materials, promoting the high added value utilization of biomass waste, with low energy consumption and high efficiency, and reducing overall costs.

[0004] To this end, the present invention provides the following technical solutions.

[0005] The present invention provides a method for the coordinated treatment of biomass waste and industrial waste salt, comprising the following steps: S1: heating the industrial waste salt to melt it; S2: mixing the biomass waste, a dopant and the molten industrial waste salt, and performing a carbonization reaction to obtain a molten mixture; S3: pulping the molten mixture to obtain a first slurry, adding a frother, and flotation to obtain a carbon material and a second slurry; S4: separating the second slurry into solid and liquid to obtain salt particles and a salt solution; the dopant comprises a compound containing N and / or S.

[0006] In the method for coordinated treatment of biomass waste and industrial waste salt provided by the present invention, typically and non-limitingly, the method for heating the industrial waste salt does not need to be specifically limited, and can be electric heating, or heating by combustion of fuels such as natural gas and petroleum gas, or using high-temperature flue gas, steam, etc. generated by other systems to preheat the industrial waste salt first, and then perform subsequent heating, and the selection can be made according to the cost budget and actual working conditions.

[0007] Optionally, in S1, the heating temperature is ≥900°C; optionally, the heating temperature is 900-1400°C.

[0008] Optionally, in S2, the temperature of the carbonization reaction is 900-1400°C, the time is 30-120 minutes, and the carbonization reaction is carried out under a protective atmosphere. The temperature and time of the carbonization reaction can be adjusted according to the state of the raw materials and the adaptability to the demand for the final product. For example, increasing the carbonization reaction temperature and increasing the carbonization reaction time can promote the increase in the size of graphite crystallites in the carbon material, reduce the spacing between graphite sheets, and promote the ordering of the carbon material; reducing the carbonization reaction temperature and reducing the carbonization reaction time can increase the spacing between graphite sheets and improve the disorder of the carbon material.

[0009] Optionally, in S2, the mass ratio of the industrial waste salt to the biomass waste is 2 to 10:1.

[0010] Optionally, in S2, the mass of the dopant is 1% to 10% of the mass of the biomass waste.

[0011] Optionally, in S3, the solid content of the first slurry is ≤15%; optionally, the solid content of the first slurry is 8% to 10%.

[0012] Optionally, in S3, the mass of the foaming agent added to each ton of the first slurry is 2 to 10 g.

[0013] Optionally, in S3, pulping is performed under stirring, and the size of the particles in the first slurry is ≤0.5 mm. The melting of industrial waste salt will generate large pieces of material, and in the process of obtaining the molten mixture, the carbon material generated by the biomass waste will be wrapped up. Pulping under stirring can break up the large pieces of material and dissociate the carbon material therein. At the same time, the fine particles have better dispersibility and fluidity in the slurry, which is beneficial to the transportation and flotation operations of the material.

[0014] Optionally, the process further includes returning the salt solution to S3 to participate in pulping, thereby realizing the recycling of water resources and making full use of the foaming agent and industrial salt dissolved therein.

[0015] Optionally, the flotation includes 1 to 5 levels of flotation.

[0016] Optionally, in S4, the solid-liquid separation method includes at least one of centrifugal filtration, filter pressing, and vacuum filtration, so as to better filter out the water in the salt particles, and the water content in the salt particles after solid-liquid separation can be less than 10%.

[0017] Optionally, the dopant includes at least one of urea, sulfur, thiourea, melamine, aniline, and thiophene.

[0018] Optionally, the foaming agent includes at least one of a natural foaming agent, an alcohol foaming agent, an ether alcohol foaming agent, and an ester foaming agent; optionally, the foaming agent includes at least one of pine oil, camphor oil, ethylene glycol, methyl isobutyl carbinol, polyether alcohol, ethylene glycol ether, alkyl phosphate, and ethyl stearate.

[0019] Optionally, the biomass waste is in a dry state and has a size of ≤0.2 mm; typically, but not limitedly, any biomass waste generated in industrial and agricultural production can be used, such as straw, rice husks, peanut shells, sawdust, discarded corks, etc.; the spare biomass waste can be dried and ground to a size of ≤0.2 mm.

[0020] Optionally, the melting point of the industrial waste salt is ≤900°C; Optionally, the industrial waste salt includes sodium ions and at least one of chloride ions, nitrate ions, and chlorate ions; Further optionally, the industrial waste salt also includes at least one of magnesium ions, iron ions, calcium ions, aluminum ions, carbonate ions, and sulfate ions. Typically, the industrial waste salt used can come from the pesticide industry, pharmaceutical industry, coal chemical industry, printing and dyeing industry, etc.

[0021] Optionally, the protective atmosphere includes at least one of a nitrogen atmosphere and an inert gas atmosphere.

[0022] The present invention provides a regenerated industrial salt, which is obtained by the salt particles obtained in the above-mentioned biomass waste and industrial waste salt collaborative treatment method; optionally, the salt particles are dried to obtain the regenerated industrial salt. Typically, but not limited to, the salt particles can be dried by air drying, or by using the heat of steam, high-temperature flue gas, heat transfer oil and other working fluids to dry, or by electric heating to dry the salt particles.

[0023] The present invention provides a carbon material, which is obtained by the above-mentioned coordinated treatment of biomass waste and industrial waste salt; optionally, it also includes the steps of washing and drying the carbon material. Wherein, if the step of washing the carbon material and the coordinated treatment of biomass waste and industrial waste salt are carried out in the same system, the wastewater after washing the carbon material can be used to participate in the pulping step.

[0024] The present invention provides an application of the above-mentioned carbon material in preparing a negative electrode material for a secondary battery; optionally, the secondary battery includes any one of a lithium ion battery and a sodium ion battery.

[0025] The beneficial effects of the present invention are:

[0026] The method for co-processing biomass waste and industrial waste salt provided by the present invention comprises the following steps: S1: heating industrial waste salt to melt it; S2: mixing biomass waste, doping agent and molten industrial waste salt, and performing carbonization reaction to obtain a molten mixture; S3: slurrying the molten mixture to obtain a first slurry, adding a frother, and flotation to obtain a carbon material and a second slurry; S4: solid-liquid separation of the second slurry to obtain salt particles and a salt solution; the doping agent comprises a compound containing N and / or S. The co-processing method uses molten industrial waste salt as a heat source and medium for carbonizing biomass waste, and simultaneously realizes the preparation of carbon materials from biomass waste and harmless treatment of industrial waste salt, promotes high value-added utilization of biomass waste, has low energy consumption and high efficiency, and reduces overall costs.

[0027] Biomass waste itself has a special texture and texture characteristics, and can still retain its microstructure after carbonization. The trace elements contained in it, such as potassium and silicon, also activate the carbon skeleton during the heat treatment process, which can help the carbonized carbon material have more abundant pores. The temperature at which the industrial waste salt is heated to melt is sufficient to remove the organic impurities therein, and the molten industrial waste salt has better thermal conductivity, a wider temperature range, higher phase change latent heat and volume heat capacity than high-temperature salt solutions; it has excellent high heat storage capacity and heat transfer performance, and can also serve as a good thermochemical medium, and can act as a template to assist in the formation of porous structures. Using molten industrial waste salt as a carbonization medium can promote element doping and the growth of two-dimensional carbon structures, forming a rich metal ion intercalation space, and realizing the one-step preparation of carbon materials that can be used as negative electrode materials for secondary batteries. Based on the difference in hydrophilicity between carbon materials and industrial salts, the carbon materials are separated from the first slurry by flotation, and then the salt particles are separated from the second slurry by solid-liquid separation. This is simple and fast, does not require cumbersome evaporation and crystallization, and reduces energy consumption. Using compounds containing N and / or S as dopants, N and S heteroatoms can be added to the skeleton of the carbon material obtained by carbonization, increasing the spacing between graphite sheets in the graphite microcrystals of the carbon material, and forming an intercalation space to accommodate metal ions, so that the obtained carbon material can be used as a secondary battery negative electrode. And melting the industrial waste salt first can also help increase the heating rate of biomass waste in subsequent steps, promote the rapid release of volatile matter, that is, the volatilization and release of substances from biomass waste during pyrolysis and carbonization, and then promote the formation of a porous structure; at the same time, it accelerates the formation of a two-dimensional structure of carbon materials from biomass waste, reduces the volatilization of N and S elements in the dopant before its formation, and is conducive to the doping of N and S elements into carbon materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 Schematic diagram of the process flow of the method for co-processing biomass waste and industrial waste salt used in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the process flow of the method for co-processing biomass waste and industrial waste salt used in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0032] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0033] Experimental drugs

[0034] Cotton straw: industrial analysis and elemental analysis are shown in Table 1.

[0035] Table 1

[0036]

[0037] Industrial waste salt: Chlorobenzene pesticide waste salt, containing 97.4wt% sodium chloride, the main organic impurities are chlorobenzene, ether and phenol organic matter, and the organic content is 2.2wt%.

[0038] Example 1

[0039] This embodiment provides a method for the coordinated treatment of biomass waste and industrial waste salt, and its process flow diagram is as follows: Figure 1 As shown, the specific steps include:

[0040] (1) Industrial waste salt is heated to 900°C in an electric furnace to melt it. Cotton stalks are dried to a moisture content of about 5% and crushed to a size of less than 0.1 mm.

[0041] (2) Add cotton straw and dopant thiourea into an electric furnace and mix them evenly with molten industrial waste salt, wherein the mass of thiourea is 2% of the mass of cotton straw, and the mass ratio of industrial waste salt to cotton straw is 5:1; maintain the temperature of the electric furnace at 900° C., and perform carbonization reaction for 60 minutes under a nitrogen atmosphere to obtain a molten mixture.

[0042] (3) The molten mixture is cooled to 45±5°C and pulped under stirring (the water used for pulping includes salt solution, wastewater and additional water circulated in the system) to obtain a first slurry with a solid content of 8% and a particle size of ≤0.5 mm; the first slurry is subjected to two-stage flotation, and ethylene glycol is added as a frother in the first flotation tank in an amount of 5 g ethylene glycol per ton of the first slurry. After the flotation, carbon material and a second slurry are obtained. The carbon material is washed and dried to obtain a clean carbon material, and the wastewater generated by washing the carbon material can be returned to participate in pulping.

[0043] (4) The second slurry is filtered using a vacuum filter with a filter cloth aperture of 400 mesh and a pressure of 20 kPa to obtain salt particles and salt solution; the salt solution is returned to step (3) to participate in pulping, and the moisture content of the salt particles is 13%. After 3 days of natural drying, the moisture content is reduced to below 5%, thereby becoming a regenerated industrial salt product.

[0044] The environmental industry standard "Determination of Organic Matter in Solid Waste - Loss on Ignition Method" (HJ 761-2015) was used to determine the content of organic matter in the regenerated industrial salt product. The results showed that the chlorobenzene organic matter in the industrial waste salt was fully decomposed and carbonized, the organic matter content was less than 50ppm, and the organic matter removal rate was as high as over 99%, achieving good detoxification and impurity removal effects.

[0045] Example 2

[0046] This embodiment provides a method for the coordinated treatment of biomass waste and industrial waste salt, and its process flow diagram is as follows: Figure 1 As shown, the specific steps include:

[0047] (1) Industrial waste salt is heated to 900°C in an electric furnace to melt it. Cotton stalks are dried to a moisture content of about 5% and crushed to a size of less than 0.1 mm.

[0048] (2) Cotton straw and doping agent urea are added into an electric heating furnace and mixed evenly with molten industrial waste salt, wherein the mass of urea is 10% of the mass of cotton straw, and the mass ratio of industrial waste salt to cotton straw is 10:1; the electric heating furnace is heated to 1400° C., and carbonization reaction is carried out for 30 minutes under a nitrogen atmosphere to obtain a molten mixture.

[0049] (3) The molten mixture is cooled to 45±5°C and pulped under stirring (the water used for pulping includes salt solution, wastewater and additional water circulated in the system) to obtain a first slurry with a solid content of 15% and a particle size of ≤0.5 mm; the first slurry is subjected to two-stage flotation, and pine oil is added as a foaming agent in the first flotation tank in an amount of 10 g pine oil per ton of the first slurry. After the flotation, carbon material and a second slurry are obtained. The carbon material is washed and dried to obtain a clean carbon material, and the wastewater generated by washing the carbon material can be returned to participate in pulping.

[0050] (4) The second slurry is filtered using a vacuum filter with a filter cloth aperture of 400 mesh and a pressure of 20 kPa to obtain salt particles and salt solution; the salt solution is returned to step (3) to participate in pulping, and the moisture content of the salt particles is 12%. After 3 days of natural drying, the moisture content is reduced to below 5%, thereby becoming a regenerated industrial salt product.

[0051] The organic matter content in the regenerated industrial salt product is less than 60ppm, and the removal rate of organic matter is greater than 99%.

[0052] Example 3

[0053] This embodiment provides a method for the coordinated treatment of biomass waste and industrial waste salt, and its process flow diagram is as follows: Figure 1 As shown, the specific steps include:

[0054] (1) Industrial waste salt is heated to 1400°C in an electric furnace to melt it. Cotton stalks are dried to a moisture content of about 5% and crushed to a size of less than 0.1 mm.

[0055] (2) Cotton straw and dopant aniline are added to an electric heating furnace and mixed evenly with molten industrial waste salt, wherein the mass of aniline is 1% of the mass of cotton straw, and the mass ratio of industrial waste salt to cotton straw is 2:1; the electric heating furnace is maintained at 900° C. and carbonization reaction is carried out for 120 minutes under a nitrogen atmosphere to obtain a molten mixture.

[0056] (3) The molten mixture is cooled to 45±5°C and pulped under stirring (the water used for pulping includes salt solution, wastewater and additional water circulated in the system) to obtain a first slurry, the solid content of which is 10%, and the size of the particles is ≤0.5mm; the first slurry is subjected to two-stage flotation, and camphor oil is added as a foaming agent in the first flotation tank, the amount of which is 2g of camphor oil per ton of the first slurry, and the carbon material and the second slurry are obtained after the flotation. The carbon material is washed and dried to obtain a clean carbon material, and the wastewater generated by washing the carbon material can be returned to participate in pulping.

[0057] (4) The second slurry is filtered using a vacuum filter with a filter cloth aperture of 400 mesh and a pressure of 20 kPa to obtain salt particles and salt solution; the salt solution is returned to step (3) to participate in pulping, and the moisture content of the salt particles is 14%. After 3 days of natural drying, the moisture content is reduced to below 5%, thereby becoming a regenerated industrial salt product.

[0058] The organic matter content in the regenerated industrial salt product is less than 30ppm, and the removal rate of organic matter is greater than 99%.

[0059] Comparative Example 1

[0060] This comparative example provides a method for the coordinated treatment of biomass waste and industrial waste salt, and its process flow diagram is as follows: Figure 2 As shown, the specific steps include:

[0061] (1) Dry the cotton straw to a moisture content of about 5%.

[0062] (2) Cotton straw, doping agent thiourea and industrial waste salt are mixed to obtain a mixture, wherein the mass of thiourea is 2% of the mass of the cotton straw, and the mass ratio of the industrial waste salt to the cotton straw is 5:1, and the mixture is crushed to a size of less than 0.1 mm.

[0063] (3) The mixture was placed in an electric heating furnace, heated to 900° C. and maintained at that temperature, and carbonized for 60 min under a nitrogen atmosphere to obtain a molten mixture.

[0064] (4) The molten mixture is cooled to 45±5°C and pulped under stirring (the water used for pulping includes salt solution, wastewater and additional water circulated in the system) to obtain a first slurry, the solid content of which is 8%, and the size of the particles is ≤0.5mm; the first slurry is subjected to two-stage flotation, and ethylene glycol is added as a frother in the first flotation tank, with an amount of 5g of ethylene glycol per ton of the first slurry. After the flotation, carbon material and a second slurry are obtained. The carbon material is washed and dried to obtain a clean carbon material, and the wastewater generated by washing the carbon material can be returned to participate in pulping.

[0065] (5) The second slurry is filtered using a vacuum filter with a filter cloth aperture of 400 mesh and a pressure of 20 kPa to obtain salt particles and salt solution; the salt solution is returned to step (3) to participate in pulping, and the moisture content of the salt particles is 13%. After 3 days of natural drying, the moisture content is reduced to below 5%, thereby becoming a regenerated industrial salt product.

[0066] Test Example 1

[0067] Take the clean carbon material obtained in the examples and comparative examples. Determine the ash content of the carbon negative electrode material according to the national standard "Analysis Method for Ash Content of Forestry Biomass Raw Materials" (GB / T 36057-2018). The yield of the carbon material is defined as the percentage of the mass of the prepared carbon material to the mass of the biomass waste raw material. Determine the specific surface area of ​​the carbon material with reference to the standard "Gas Adsorption BET Method for Determination of Specific Surface Area of ​​Solid Matter" (GB / T19587-2017).

[0068] The clean carbon material obtained in the examples and comparative examples was used as the carbon negative electrode material, and assembled into a half-cell to measure the performance of the carbon negative electrode material. The specific operation is as follows: the carbon negative electrode material, the conductive agent acetylene black, and the binder PVDF were added to a mortar at a mass ratio of 7:2:1, and an appropriate amount of NMP (N-methylpyrrolidone) was added and ground into a uniform paste, and then transferred to the current collector copper foil, and coated with a film applicator with a thickness of 100 μm, and the coated copper foil was placed in a vacuum drying oven, dried under vacuum at 100 ° C for 12 hours, and cut into 14 mm diameter discs with a button battery manual slicer to obtain a battery negative electrode sheet. Take a CR2016 battery shell, use the above-mentioned battery negative electrode sheet as the negative electrode, a 19mm diameter whatman GF / D disc as a diaphragm, a 16mm diameter sodium sheet as the counter electrode, and a 1M NaClO4 EC / DMC (ethylene carbonate / dimethyl carbonate) solution (volume ratio 1:1) as the electrolyte. In a glove box filled with argon, a button battery sealer is used to assemble the button battery. The LandCT2001A battery test system is used to perform half-cell cyclic voltammetry test and AC impedance test, and the voltage range is set to 0.01-3.0V. The discharge specific capacitance of 10 cycles is determined at a constant rate of 0.2C. The charge transfer resistance is determined according to the electrochemical impedance diagram, and the frequency range is set to 0.01-100kHz. The yield, ash content, specific surface area and electrode performance of the carbon materials obtained in the embodiments and comparative examples are shown in Table 2.

[0069] Table 2

[0070]

[0071] As can be seen from Table 2, the specific surface area of ​​the carbon material obtained in the embodiment is significantly higher than that of the carbon material obtained in the comparative example, and the charge transfer resistance is significantly lower than that of the carbon material obtained in the comparative example. The material ratio, carbonization time and temperature conditions of comparative example 1 are the same as those of embodiment 1. The difference between the two is that in embodiment 1, the biomass waste is mixed with industrial waste salt for carbonization after the industrial waste salt is melted, while in comparative example 1, the biomass waste is mixed with industrial waste salt at room temperature and then heated. In embodiment 1, the molten high-temperature industrial waste salt is mixed with the biomass waste, and the biomass waste is quickly heated from all sides by heat conduction; while in comparative example 1, the whole mixture needs to be heated by heat radiation from an electric furnace; the rate of heat transfer in embodiment 1 is much higher than that in comparative example 1. That is, relative to the method in embodiment 1, the heating rate of the biomass waste in comparative example 1 is slow, and the release of volatiles is relatively mild, so there are fewer pore structures formed in the carbon material. As shown in Table 2, the specific surface area of ​​the carbon material obtained in comparative example 1 is significantly lower than that in embodiment 1. On the other hand, the N and S elements in the dopant will volatilize and release during the slow heating process before the industrial salt melts, which reduces the formation of the two-dimensional sheet doping structure in the carbon material, resulting in a decrease in the discharge specific capacity and an increase in the charge transfer resistance of Comparative Example 1. The carbon material obtained by the method for co-processing biomass waste and industrial waste salt in the present invention has excellent electrical properties and can be used to prepare negative electrode materials for secondary batteries.

[0072] In the examples, the carbonization time of Example 1 is longer, the two-dimensional structure of the carbon material grows fully, and the electrode performance of the obtained carbon material is better. The carbonization temperature of Example 2 is higher than that of Example 1, reaching 1400°C, and the two-dimensional structure of the carbon material grows faster. 30 minutes of carbonization can form a carbon material with a fully grown two-dimensional structure, achieving a discharge specific capacity close to that of the carbon material carbonized at 900°C for 60 minutes (Example 1). Since the proportion of dopants in Example 2 is higher, the conductivity of the electrode is improved, so the charge transfer resistance is lower than that of Example 1. Example 3 increases the carbonization time relative to Example 1, but the dopant ratio is relatively small, resulting in a shorter spacing between graphite sheets, resulting in a low sodium ion capacity and a reduced discharge specific capacity.

[0073] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A method for the coordinated treatment of biomass waste and industrial waste salt, characterized in that: The steps include: S1: heating industrial waste salt to melt it; S2: mixing biomass waste, doping agent and molten industrial waste salt, and performing carbonization reaction to obtain a molten mixture; S3: slurrying the molten mixture to obtain a first slurry, adding a frother, and flotation to obtain a carbon material and a second slurry; S4: separating the second slurry into solid and liquid to obtain salt particles and salt solution; The dopant includes a N and / or S-containing compound.

2. The collaborative processing method according to claim 1, characterized in that: In S1, the heating temperature is ≥900°C; optionally, the heating temperature is 900-1400°C.

3. The collaborative processing method according to claim 1 or 2, characterized in that: In S2, the temperature of the carbonization reaction is 900-1400°C, the time is 30-120 min, and the carbonization reaction is carried out under a protective atmosphere; And / or, in S2, the mass ratio of the industrial waste salt to the biomass waste is 2 to 10:1; And / or, in S2, the mass of the dopant is 1% to 10% of the mass of the biomass waste.

4. The collaborative processing method according to any one of claims 1 to 3, characterized in that: In S3, the solid content of the first slurry is ≤15%; optionally, the solid content of the first slurry is 8% to 10%; And / or, in S3, the mass of the foaming agent added to each ton of the first slurry is 2 to 10 g; And / or, in S3, slurrying is carried out under stirring, and the size of particles in the first slurry is ≤0.5 mm.

5. The collaborative processing method according to any one of claims 1 to 4, characterized in that: The process also includes returning the salt solution to S3 to participate in pulping.

6. The collaborative processing method according to any one of claims 1 to 5, characterized in that: The flotation includes 1 to 5 levels of flotation; And / or, in S4, the solid-liquid separation method includes at least one of centrifugal filtration, filter press, and vacuum filtration.

7. The collaborative processing method according to any one of claims 1 to 6, characterized in that: The doping agent includes at least one of urea, sulfur, thiourea, melamine, aniline, and thiophene; And / or, the foaming agent includes at least one of a natural foaming agent, an alcohol foaming agent, an ether alcohol foaming agent, and an ester foaming agent; optionally, the foaming agent includes at least one of pine oil, camphor oil, ethylene glycol, methyl isobutyl carbinol, polyether alcohol, ethylene glycol ether, alkyl phosphate, and ethyl stearate; And / or, the biomass waste is in a dry state and has a size of ≤0.2 mm; And / or, the melting point of the industrial waste salt is ≤900°C; optionally, the industrial waste salt includes sodium ions and at least one of chloride ions, nitrate ions, and chlorate ions; further optionally, the industrial waste salt also includes at least one of magnesium ions, iron ions, calcium ions, aluminum ions, carbonate ions, and sulfate ions; And / or, the protective atmosphere includes at least one of a nitrogen atmosphere and an inert gas atmosphere.

8. A regenerated industrial salt, characterized in that: The salt particles are obtained by using the method for co-processing biomass waste and industrial waste salt as described in any one of claims 1 to 7; optionally, the salt particles are dried to obtain the regenerated industrial salt.

9. A carbon material, characterized in that It is prepared by co-processing the biomass waste and industrial waste salt as described in any one of claims 1 to 7; optionally, it also includes the steps of washing and drying the carbon material.

10. Use of the carbon material as claimed in claim 9 in preparing negative electrode materials for secondary batteries; optionally, the secondary battery comprises any one of a lithium ion battery and a sodium ion battery.

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