Coal-based hard carbon deashing regulation method based on multi-field coupling mass transfer kinetics

Abstract

This invention discloses a method for controlling the deashing of coal-based hard carbon based on multi-field coupled mass transfer kinetics, belonging to the technical fields of sodium-ion battery anode material preparation and coal-based hard carbon purification. The method first obtains the occurrence characteristics of free, encapsulated, and lattice-state ash, and calculates the mass transfer resistance coefficient at the coal-based hard carbon-deashing agent interface. It then predicts the directional migration flux of ash ions by combining temperature field thermal diffusion, ultrasonic cavitation, and interfacial mass transfer resistance, and calculates the deashing reaction kinetic rate constant accordingly. Using deashing depth and hard carbon structural damage as optimization objectives, it performs multi-objective optimization of temperature, electric field strength, ultrasonic power density, and reaction time to obtain a combination of process parameters, and performs multi-field coupled deashing according to this parameter combination. This invention can establish a quantitative relationship between ash occurrence, mass transfer, reaction kinetics, and process parameters, realizing the control of the coal-based hard carbon deashing process.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery anode material preparation and coal-based hard carbon purification technology, specifically involving a coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics. Background Technology

[0002] Coal-based hard carbon is widely used in sodium-ion battery anode materials due to its abundant resources, low cost, and stable electrochemical performance. However, raw coal contains a large amount of ash impurities, mainly including SiO2, Al2O3, and Fe2O3. These ash particles form inert phases during hard carbon preparation, reducing the specific capacity, rate performance, and cycle life of the hard carbon. Therefore, deep deashing is a key step in the preparation of high-performance coal-based hard carbon.

[0003] Existing coal-based hard carbon deashing processes mainly fall into two categories: physical deashing and chemical deashing. Physical deashing methods, such as gravity separation, flotation, and magnetic separation, primarily utilize the differences between mineral components and coal-based components in terms of density, surface properties, or magnetic properties to separate them. They can remove some free ash, but their removal effect is limited for encapsulated ash inside coal particles and lattice-like ash that is tightly bound to the coal-based structure. Therefore, after treatment using physical deashing methods, the hard carbon ash content is usually still higher than 1%.

[0004] Chemical deashing methods mainly include acid leaching, alkali leaching, and combined acid-alkali methods. These methods utilize the chemical reaction between acids, alkalis, and inorganic ash to promote ash dissolution, achieving a higher deashing depth compared to physical deashing. However, existing chemical deashing processes still have the following problems.

[0005] First, ash removal is incomplete. Ash in raw coal exists in different forms, including free, encapsulated, and lattice states. These different forms exhibit varying degrees of bonding with the coal's matrix structure, resulting in differences in mass transfer conditions and reactivity. Existing processes typically employ uniform acid / alkali concentrations, reaction temperatures, and reaction times, making it difficult to implement differentiated removal strategies for different ash forms. Free ash is relatively easy to contact and react with deashing agents, while encapsulated ash is limited by the porosity and encapsulation structure of coal particles. The reactivity of lattice ash is further restricted by its state of existence, making complete removal of lattice ash particularly difficult.

[0006] Second, the hard carbon structure is severely damaged. To further improve the deashing depth, existing chemical deashing processes often employ higher reaction temperatures, higher concentrations of acids and alkalis, and longer reaction times. However, while these conditions enhance ash dissolution, they also intensify the effect of the deashing agent on the coal-based structure, leading to damage to the layered structure of hard carbon, a sharp increase in specific surface area, and a significant decrease in the initial coulombic efficiency. Therefore, coal-based hard carbon deashing is not simply about achieving the lowest possible ash content; rather, there is a trade-off between "improving the deashing depth" and "reducing damage to the hard carbon structure." Simply increasing the reaction intensity to achieve a lower ash content can easily lead to overtreatment; conversely, reducing the reaction intensity to protect the hard carbon structure may result in insufficient removal of encapsulated and lattice-state ash.

[0007] Third, the process parameters are largely arbitrary. In existing deashing processes, parameters such as reaction temperature, acid / alkali concentration, and reaction time are mainly determined through experience and trial-and-error experiments, lacking theoretical basis that reflects the ash occurrence characteristics, mass transfer state, and reaction kinetics of the raw materials. When the coal type, ash composition, or ash occurrence ratio changes, the original process parameters are difficult to apply directly, usually requiring multiple sets of experiments for parameter screening. Therefore, existing methods struggle to establish a direct link between the characteristics of coal-based hard carbon raw materials and process parameters, and also fail to make targeted adjustments to process conditions based on different raw material states, thus failing to achieve a precise balance between "maximizing deashing depth" and "minimizing structural damage."

[0008] Fourth, the mass transfer efficiency is relatively low. Chemical deashing involves more than just the chemical reaction between the deashing agent and ash; it also includes the transfer of the deashing agent to the surface and internal pores of coal particles, mass transfer at the solid-liquid interface, and the migration of ions formed by ash dissolution from the particle interior to the liquid phase. The pore structure of coal particles and the presence of the solid-liquid interface create mass transfer resistance. When the interfacial mass transfer or ion migration rate is lower than the chemical reaction rate, even increasing the acid / alkali concentration or temperature will not proportionally increase the actual deashing rate; instead, it may increase structural damage and energy consumption. Current mass transfer resistance analyses primarily consider bulk mass transfer in the liquid phase, paying insufficient attention to the differences in interfacial mass transfer caused by different ash occurrence forms.

[0009] Therefore, the difficulty of existing coal-based hard carbon deashing processes is not simply "the difficulty in removing ash," but rather that the limiting factors for different ash occurrence forms are different. The removal of free ash is mainly affected by its contact with the deashing agent and reaction conditions; encapsulated ash is also limited by the mass transfer within the coal particles and the encapsulation structure; lattice ash is further limited by its own reactivity. If these differences cannot be identified and quantified, simply increasing a single process parameter is unlikely to simultaneously improve the removal efficiency of all types of ash.

[0010] In recent years, multi-field coupling technology has been gradually applied to the field of mineral deashing. For example, temperature field, electric field and ultrasonic field are introduced into the deashing process. Temperature is used to promote diffusion and reaction, electric field is used to affect the migration of charged ions, and the microjets and impacts generated by ultrasonic cavitation are used to enhance the mass transfer process, thereby improving deashing efficiency and reaction rate.

[0011] However, existing research on multi-field coupled deashing mainly focuses on observing macroscopic results such as deashing rate after changes in experimental conditions. Different external fields are not independent of each other; their effects may simultaneously involve multiple processes, including solid-liquid interface state, internal particle mass transfer, ash ion migration, and chemical reactions. Therefore, simply stating that "the deashing effect improves after adding an electric or ultrasonic field" is insufficient to solve the process control problem. When temperature, electric field strength, and ultrasonic power density change simultaneously, the extent to which each external field affects interfacial mass transfer, ion migration, and reaction kinetics, and how these different effects interact and constrain each other, still lacks clear quantitative relationships.

[0012] In particular, existing technologies have not yet established a theoretical model that can continuously describe the intrinsic relationship between ash occurrence characteristics, interfacial mass transfer, ash molecule migration, reaction kinetics, and process parameters. Without the aforementioned quantitative transfer relationships, even with synergistic enhancement using temperature, electric, and ultrasonic fields, it is still necessary to rely on numerous experiments to determine the external field parameters. It is difficult to determine whether the deashing gain obtained by increasing the intensity of a certain external field is sufficient to compensate for the resulting damage to the hard carbon structure, and it is also difficult to directly determine appropriate process parameters based on different coal types and different ash occurrence states. Therefore, existing multi-field coupled deashing methods have not yet escaped the empirical trial-and-error parameter optimization approach.

[0013] In summary, existing deep deashing technologies for coal-based hard carbon still need to address the following interrelated technical challenges: The first question is how to characterize the different mass transfer and reaction constraints of ash in the free state, encapsulated state and lattice state based on their occurrence differences; Secondly, how to quantify the coupling effects of temperature field, electric field and ultrasonic field on solid-liquid interface mass transfer and ash ion migration process; Third, how to further establish a connection between the ash ion migration process and the deashing reaction kinetics; fourth, how to determine process parameters based on raw material characteristics and mass transfer and reaction state, so as to improve the deashing depth while reducing damage to the hard carbon structure.

[0014] The aforementioned issues constitute the main technical obstacles to achieving precise control in existing coal-based hard carbon multi-field coupled deep deashing processes. Summary of the Invention

[0015] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics. This method addresses the difficulties in differentiating the removal of ash in different morphologies (free, encapsulated, and lattice-state) in existing coal-based hard carbon deashing processes. Furthermore, the use of high temperatures, high-concentration acids and alkalis, and prolonged reactions to increase deashing depth can easily damage the hard carbon structure. Process parameters are mainly determined through trial and error, making it difficult to balance deashing depth and hard carbon structural integrity. Additionally, single chemical deashing processes suffer from high interfacial mass transfer resistance within coal particle pores, limiting ash ion migration and reaction rates. Moreover, existing multi-field coupled deashing technologies lack quantitative correlations between ash occurrence characteristics, interfacial mass transfer, ion migration, reaction kinetics, and process parameters, making precise control of temperature, electric field strength, ultrasonic power density, and reaction time difficult.

[0016] The present invention adopts the following technical solution: A coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics includes the following steps: The mass fractions of free, encapsulated, and lattice-state ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, are obtained, and the weighting factor of ash occurrence form is determined based on the mass fractions. Based on Fick's first law and Young's equation, the mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface is calculated according to the weighting factor of the ash occurrence morphology and the interfacial tension correction term and wetting angle correction term under the action of temperature field, electric field and ultrasonic field. Based on the Nernst-Planck equation, the directional migration flux of ash ions is calculated according to the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interface mass transfer resistance correction term determined by the interface mass transfer resistance coefficient. Based on the Arrhenius equation, the deashing reaction kinetic rate constant is calculated according to the multi-field coupling synergistic effect coefficient, the ash ion migration restriction factor determined by the directional migration flux, and the ash inclusion breakage probability term. Based on Pareto optimality theory and response surface methodology, and taking the deashing reaction kinetic rate constant as the optimization objective, the temperature, electric field strength, ultrasonic power density and reaction time are optimized in multiple objectives to obtain the process parameter combination. According to the combination of process parameters, coal-based hard carbon is deashed under the coupling conditions of temperature field, electric field and ultrasonic field.

[0017] Furthermore, obtaining the ash content morphology weighting factor includes: Crushing, screening and pretreatment of coal-based hard carbon raw materials; X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were used to analyze the pretreated coal-based hard carbon raw materials to determine the mass fractions of free ash, encapsulated ash, and lattice ash, and to determine the corresponding ash occurrence format weighting factor based on each mass fraction.

[0018] Furthermore, the mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface is calculated according to the following formula:

[0019] in, The mass transfer resistance coefficient at the coal-based hard carbon-deashing agent interface; The effective diffusion coefficient of the deashing agent in the pores of coal-based hard carbon; Assign a number to the ash content storage format. Represents free-state ash. Indicates the ash content in the encapsulated state. Represents lattice-state ash content; For the first The weighting factor of the ash content distribution form, and ; For temperature electric field strength and ultrasonic power density Solid-liquid interfacial tension under action; The solid-liquid interfacial tension is defined as the solid-liquid interfacial tension under normal temperature, pressure, and no external field conditions. For the first Ash occurrence forms at temperature electric field strength and ultrasonic power density Solid-liquid wetting angle under action; The thickness of the solid-liquid interface boundary layer.

[0020] Furthermore, the first The directional migration flux of ash ions is calculated using the following formula:

[0021] in, For the first Directed migration flux of ash ions; This is the correction factor for interfacial mass transfer resistance. For the first The diffusion coefficient of ash ions in the deashing agent; For the first Bulk concentration of ash ions; For the first The charge number of the ash ions; It is Faraday's constant; It is the gas constant; Thermodynamic temperature; It is the electric potential; The Soret coefficient; For temperature gradient; The ultrasonic cavitation efficiency coefficient; Ultrasonic power density; The flow rate of the deashing agent in the liquid phase is denoted as ...

[0022] Furthermore, the kinetic rate constant of the deashing reaction is calculated according to the following formula:

[0023] in, The kinetic rate constant for the deashing reaction under multi-field coupling conditions; It is the intrinsic reaction rate constant under normal temperature, normal pressure, and no external field conditions; For temperature electric field strength and ultrasonic power density The corresponding multi-field coupling synergistic effect coefficient; It is the migration restriction factor for ash ions; This represents the ultimate migration flux; These are the weighting factors for free ash, encapsulated ash, and lattice ash, respectively. The probability of ultrasonic fragmentation of encapsulated ash; This is the correction coefficient for the reactivity of lattice-state ash. This is the intrinsic activation energy of the deashing reaction; It is the gas constant; It is the thermodynamic temperature.

[0024] Furthermore, the comprehensive optimization objective function of the multi-objective optimization is:

[0025] in, To comprehensively optimize the objective function, the temperature corresponding to its maximum value is... electric field strength Ultrasonic power density and reaction time The combination of these is the process parameter combination; This is a trade-off coefficient between deashing depth and hard carbon structural damage. ; The kinetic rate constant of the deashing reaction is denoted as . and , and , and , and These represent the ranges of values ​​for temperature, electric field strength, ultrasonic power density, and reaction time, respectively. These are the weighting coefficients for temperature, electric field strength, ultrasonic power density, and reaction time on the damage degree of hard carbon structures, respectively. .

[0026] Furthermore, when calculating the mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface, the effective diffusion coefficient of the deashing agent in the pores of the coal-based hard carbon is determined by constant pressure permeation experiment, and the thickness of the solid-liquid interface boundary layer is determined by laser Doppler velocimeter. When calculating the directional migration flux of the ash ions, the diffusion coefficient and charge number of the ash ions are determined by experiments or electrochemical manuals, the Solette coefficient is determined by thermal diffusion cell experiments, and the ultrasonic cavitation efficiency coefficient and convective mass transfer coefficient are determined by experiments. In calculating the kinetic rate constant of the deashing reaction, the intrinsic reaction rate constant and intrinsic activation energy were determined by thermogravimetric analysis, the ultrasonic breakage probability of encapsulated ash was determined by scanning electron microscopy image analysis, and the reactivity correction coefficient of lattice ash was experimentally determined. In the aforementioned multi-objective optimization, the weighting coefficients of temperature, electric field strength, ultrasonic power density, and reaction time on the damage degree of hard carbon structures were determined by Raman spectroscopy, specific surface area analysis, and X-ray photoelectron spectroscopy experiments.

[0027] Furthermore, under different temperatures, electric field strengths, and ultrasonic power densities, the solid-liquid interfacial tension, solid-liquid wetting angle, and multi-field coupling synergistic effect coefficient were measured, and the functional relationships between the solid-liquid interfacial tension, solid-liquid wetting angle, and multi-field coupling synergistic effect coefficient and temperature, electric field strength, and ultrasonic power density were determined through experimental fitting.

[0028] Furthermore, according to the aforementioned process parameter combination, the pretreated coal-based hard carbon raw material and deashing agent are added to a multi-field coupled reaction device, and the reaction temperature, electric field strength, ultrasonic power density, and reaction time are set according to the aforementioned process parameter combination for deashing treatment; the deashing treatment adopts alkali-acid combined deashing: first, the coal-based hard carbon raw material and alkali solution are subjected to alkali leaching under temperature field, electric field, and ultrasonic field coupling conditions, and after filtration and separation, the alkali-leached coal-based hard carbon raw material and acid solution are subjected to acid leaching under temperature field, electric field, and ultrasonic field coupling conditions; After deashing, the coal-based hard carbon is filtered, washed until neutral, and vacuum dried to constant weight, and then carbonized under an inert atmosphere.

[0029] Secondly, embodiments of the present invention provide a coal-based hard carbon deashing control system based on multi-field coupled mass transfer kinetics, comprising: The ash occurrence characteristic analysis unit is used to obtain the mass fraction of free, encapsulated and lattice ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, and to determine the ash occurrence form weighting factor based on the mass fraction. The interfacial mass transfer resistance calculation unit is used to calculate the interfacial mass transfer resistance coefficient of coal-based hard carbon-deashing agent based on Fick's first law and Young's equation, according to the weighting factor of the ash occurrence morphology and the interfacial tension correction term and wetting angle correction term under the action of temperature field, electric field and ultrasonic field. The ion migration flux prediction unit is used to calculate the directional migration flux of ash ions based on the Nernst-Planck equation, according to the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interface mass transfer resistance correction term determined by the interface mass transfer resistance coefficient. The reaction kinetics calculation unit is used to calculate the deashing reaction kinetic rate constant based on the Arrhenius equation, according to the multi-field coupling synergistic effect coefficient, the ash ion migration restriction factor determined by the directional migration flux, and the ash inclusion fragmentation probability term. The process parameter optimization unit is used to perform multi-objective optimization of temperature, electric field strength, ultrasonic power density and reaction time based on Pareto optimal solution theory and response surface methodology, according to the deashing reaction kinetic rate constant, with deashing depth and hard carbon structure damage degree as optimization objectives, to obtain a combination of process parameters; A multi-field coupled reaction device is used to provide a temperature field, an electric field, and an ultrasonic field according to the combination of process parameters to deash coal-based hard carbon, and to monitor the reaction temperature, electric field strength, and ultrasonic power density.

[0030] Thirdly, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the above-described coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics.

[0031] Fourthly, embodiments of the present invention provide a computer-readable storage medium including a computer program, which, when executed by a processor, implements the steps of the above-described coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects: A method for controlling the deashing of coal-based hard carbon based on multi-field coupled mass transfer kinetics is proposed. This method establishes a stepwise transfer relationship between the ash occurrence state of coal-based hard carbon raw materials and the final deashing process parameters by establishing a hierarchical relationship between ash occurrence characteristics, interfacial mass transfer resistance coefficient, ash ion directional migration flux, deashing reaction kinetic rate constant, and process parameter combinations. First, the mass transfer differences of different raw materials are characterized based on the mass fraction of free, encapsulated, and lattice-state ash and interfacial characteristics. Then, the effects of temperature, electric, and ultrasonic fields on interfacial mass transfer, ash ion migration, and deashing reaction kinetics are combined to calculate the interfacial mass transfer resistance, ion migration capacity, and reaction kinetic rate stepwise, ensuring that the determination of process parameters simultaneously considers mass transfer and reaction kinetic limitations. Furthermore, with the optimization objectives of maximizing deashing depth and minimizing hard carbon structural damage, the reaction temperature, electric field strength, ultrasonic power density, and reaction time are coordinated and optimized. The resulting combination of process parameters is then directly applied to multi-field coupled depth deashing. This forms a closed-loop control process of raw material experimental characterization, mass transfer and kinetic calculation, process parameter optimization, and multi-field coupled deashing. It reduces the dependence of process parameters on experience trial and error, and avoids pursuing deashing depth simply by increasing temperature, enhancing external field effect, or extending reaction time. It is beneficial to reduce the excessive effect on hard carbon structure while improving the degree of removal of free, encapsulated, and lattice ash, and achieves coordinated control of deashing depth and hard carbon structure integrity.

[0033] Furthermore, the ash occurrence characteristics of coal-based hard carbon raw materials were analyzed. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were used to determine the phase composition, spatial distribution, and the proportions of free, encapsulated, and lattice states of ash. The solid-liquid interfacial tension and wetting angle corresponding to different occurrence forms were also measured. This technique can simultaneously obtain ash composition, occurrence state, and interfacial mass transfer characteristics, transforming the actual ash differences of different coal-based raw materials into ash occurrence form weighting factors and interfacial parameters that can be used for subsequent model calculations. This avoids treating ash with different occurrence forms as objects with the same mass transfer characteristics, providing reliable input for targeted calculation of interfacial mass transfer resistance coefficients.

[0034] Furthermore, the interfacial mass transfer resistance is calculated by combining the weighting factor of ash occurrence form, solid-liquid interfacial tension, wetting angle, effective diffusion coefficient, and interfacial boundary layer thickness, while also considering internal diffusion of coal particles and solid-liquid interfacial mass transfer conditions. In particular, the influence of external fields on the spreading and penetration capacity of deashing agents is characterized by the changes in interfacial tension and wetting state under multiple field conditions, thus establishing a quantitative link between the microscopic occurrence differences of raw materials and macroscopic mass transfer capacity.

[0035] Furthermore, based on the Nernst-Planck migration mechanism, a thermal diffusion term for the temperature field, an enhancement term for ultrasonic cavitation, and a correction for interfacial mass transfer resistance are introduced. Electromigration, concentration diffusion, and liquid phase flow are also considered to describe the actual migration process of ash ions under the combined action of multiple driving forces. Among them, the microjets and impact effects generated by ultrasonic cavitation are conducive to enhancing convective migration, the temperature gradient generates thermal diffusion, and the interfacial resistance correction can avoid overestimating the ion migration capacity based solely on the external field.

[0036] Furthermore, the multi-field coupling synergistic effect coefficient, ash ion migration restriction factor, weighted relationship of different ash occurrence forms, and ultrasonic breakage probability of encapsulated ash are introduced into the deashing reaction kinetics calculation to avoid using only temperature to describe the deashing rate. This setting considers both the influence of the external field on the reaction activation process and the limitation of the mass transfer rate on the actual reaction rate, as well as the difference in reactivity of different occurrence forms, so that the obtained kinetic rate constant can better reflect the actual multi-field coupled deashing process.

[0037] Furthermore, two optimization objectives were simultaneously set: maximizing the deashing depth and minimizing the damage to the hard carbon structure. Temperature, electric field strength, ultrasonic power density, and reaction time were normalized to avoid simply determining process parameters based on the lowest ash content. By coordinating the two objectives through a trade-off coefficient, an appropriate combination of process parameters was selected between ash removal and structural protection based on product requirements, reducing structural damage caused by excessively high temperatures, strong external fields, or excessively long reaction times.

[0038] Furthermore, constant pressure permeation, laser Doppler velocimetry, thermogravimetric analysis, thermal diffusion, Raman spectroscopy, specific surface area analysis, and XPS were used to determine the model parameters. This ensured that the model input parameters had experimental basis, and that the evaluation of interfacial mass transfer, thermal diffusion, reaction kinetics, and structural damage was supported by actual measurement results. This improved the pertinence and repeatability of parameter calculations for different coal types and different deashing systems.

[0039] Furthermore, the solid-liquid interfacial tension, wetting angle, and multi-field coupling synergistic effect coefficient were measured under different temperatures, electric field strengths, and ultrasonic power densities. The functional relationship between these coefficients and external field parameters was established, transforming the interfacial effects and synergistic reaction effects caused by changes in external field strength into quantitative parameters that can be incorporated into the model calculation. This allows temperature, electric field, and ultrasonic field to no longer be merely experimental conditions, but to directly participate in the prediction and optimization of process parameters.

[0040] Furthermore, based on the process parameter combination obtained from multi-objective optimization, the reaction temperature, electric field strength, ultrasonic power density, and reaction time are set in a multi-field coupled reaction device. Deep deashing of coal-based hard carbon is then carried out under the combined action of the temperature field, electric field, and ultrasonic field, while monitoring the relevant process parameters. This allows the results obtained from the aforementioned interfacial mass transfer, ash molecule migration, and reaction kinetics calculations to be directly applied to the actual deashing process. The temperature field promotes thermal diffusion and reaction, the electric field promotes the directional migration of charged ash molecules, and ultrasonic cavitation enhances interfacial mass transfer and facilitates the exposure of encapsulated ash. After deashing, the product undergoes further filtration, washing, drying, and inert atmosphere carbonization to remove residual deashing agent and soluble reaction products, resulting in a coal-based hard carbon product with low ash content and high structural integrity.

[0041] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0042] In summary, this invention takes the ash content state as the starting point, and sequentially links interfacial mass transfer, ion migration, reaction kinetics and process parameter optimization. It comprehensively utilizes temperature field, electric field and ultrasonic field to improve ash migration and removal capabilities, and determines process conditions through dual-objective optimization of deashing depth and structural damage, thus taking into account deep deashing, structural protection and precise parameter control.

[0043] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0044] Figure 1 This is a diagram illustrating the steps of the method of the present invention; Figure 2 This is a comparison chart of the ash content of hard carbon products from the control group and the experimental group of this invention; Figure 3 This is a comparison diagram of the structural parameters of the hard carbon products in the control and experimental groups of this invention. In this diagram, (a) shows the intensity ratio of the D peak to the G peak in the Raman spectrum. Comparison charts: (b) shows the comparison of specific surface area, and (c) shows the comparison of pore volume. Figure 4 This is a comparison chart of the electrochemical performance of the control and experimental groups of hard carbon products in this invention; Figure 5 A schematic diagram of a computer device provided in an embodiment of the present invention; Figure 6 This is a block diagram of an electronic device according to an embodiment of the present invention.

[0045] Among them, 60. Computer equipment; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] This invention provides a coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics. Addressing the problems of insufficient consideration of ash occurrence differences, high mass transfer resistance within coal particle pores, reliance on empirical trial-and-error for deashing parameters, and difficulty in simultaneously achieving deashing depth and hard carbon structural integrity in existing coal-based hard carbon deashing processes, a multi-field coupled mass transfer kinetics control system is constructed. First, based on the occurrence ratios and interface characteristics of free, encapsulated, and lattice-state ash, an interface mass transfer resistance model is established to allow raw material differences to be incorporated into subsequent calculations. Then, thermal diffusion from the temperature field, electric field driving, ultrasonic cavitation, and interface mass transfer resistance are jointly introduced into the prediction of ash molecule directional migration flux, and the migration flux is further used to correct the deashing reaction kinetic rate constant. Finally, with deashing depth and hard carbon structural damage as dual objectives, temperature, electric field strength, ultrasonic power density, and reaction time are optimized. Therefore, a quantitative link is established between the microscopic occurrence characteristics of raw materials and macroscopic process parameters, reducing the reliance on high temperature, high concentration of acid and alkali and long reaction time in the treatment method. While improving the degree of ash removal, the damage to hard carbon structure is inhibited, and the ash removal process is transformed from experience-based determination to model-based control.

[0048] Please see Figure 1 This invention discloses a coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics, comprising the following steps: S1. Ash occurrence characteristics analysis of coal-based hard carbon raw materials: The raw coal was crushed, screened and pretreated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to quantitatively analyze the occurrence forms (free state, encapsulated state, lattice state) and their mass fraction of ash in the coal. The solid-liquid interfacial tension and wetting angle corresponding to different ash occurrence forms were measured. The raw coal to be processed is crushed, screened and pretreated to form a coal-based hard carbon raw material that meets the requirements of subsequent ash content occurrence characteristic analysis; in one embodiment, the raw coal is crushed to below 200 mesh and preliminarily deashed by flotation to remove some of the free ash in the raw coal. Samples were taken from the pretreated coal-based hard carbon raw material, and the phase composition of inorganic minerals was analyzed by X-ray diffraction (XRD). The main composition of ash in the raw material was determined based on the phases corresponding to each diffraction peak. The spatial distribution and bonding state between ash particles and the coal-based carbonaceous matrix were observed by scanning electron microscopy (SEM), and the elemental composition of each observation area was determined by energy dispersive spectroscopy (EDS). Based on this, the free ash, encapsulated ash and lattice ash in the coal-based hard carbon raw material were identified. Based on the results of X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy, the ash content in different occurrence forms was quantitatively analyzed, and the mass fractions of free ash, encapsulated ash and lattice ash were obtained respectively. The corresponding ash occurrence form weighting factor was determined according to the mass fraction of each occurrence form of ash. For different ash occurrence forms, the interfacial characteristics between coal-based hard carbon raw materials and deashing agents were determined. Among them, the solid-liquid interfacial tension was determined by the pendant drop method, and the corresponding solid-liquid wetting angle was determined by the contact angle measuring instrument. Furthermore, the solid-liquid interfacial tension and solid-liquid wetting angle were determined under different temperatures, electric field strengths and ultrasonic power densities to obtain the interfacial characteristic parameters under different multi-field coupling conditions. The obtained ash occurrence morphology weighting factor, solid-liquid interfacial tension, and solid-liquid wetting angle are used as the basic input parameters for subsequent calculation of the mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface.

[0049] Based on the occurrence relationship between ash and the coal-based carbonaceous matrix, ash is classified into free, encapsulated, and lattice states, and the proportions of different occurrence forms and their corresponding solid-liquid interface characteristics are obtained. Since different occurrence forms of ash exhibit different mass transfer conditions during contact with deashing agents, wetting, and subsequent migration, converting the mass fraction of each occurrence form into a weighting factor for ash occurrence forms allows the differences in the ash composition of the raw materials to be incorporated into the subsequent interface mass transfer model, providing a basis for calculating the interface mass transfer resistance for different coal-based raw materials.

[0050] S2. Calculation of interfacial mass transfer resistance coefficient: Based on Fick's first law and Young's equation, a weighting factor for ash occurrence morphology and a correction term for interfacial tension under multi-field coupling are introduced to construct a calculation model for the interfacial mass transfer resistance coefficient of coal-based hard carbon-deashing agent, and quantitatively calculate the interfacial mass transfer resistance coefficient under different multi-field coupling conditions. Fick's First Law: The fundamental law describing mass transfer through diffusion; the original formula is:

[0051] in, For the diffusion flux of matter, The diffusion coefficient is... For the concentration gradient.

[0052] Young's Equation in interfacial chemistry: The fundamental equation describing the interfacial tension equilibrium relationship between solid, liquid, and gas phases.

[0053] in, For solid-gas interfacial tension, For solid-liquid interfacial tension, For the liquid-gas interfacial tension, The solid-liquid wetting angle.

[0054] Existing mass transfer resistance calculation models only consider the bulk resistance of the liquid phase, completely ignoring the differentiated impact of different ash occurrence forms in coal-based hard carbon on interfacial mass transfer, and also failing to consider the regulatory effect of multi-field coupling on interfacial tension and wetting angle. This invention improves the existing model through the following steps: 1) According to Fick's first law, the interfacial mass transfer flux is directly proportional to the concentration gradient and inversely proportional to the mass transfer resistance, that is:

[0055] in, The concentration difference across the interface. is the interfacial mass transfer resistance coefficient.

[0056] 2) According to Young's equation, the solid-liquid interfacial tension determines the degree of wetting of the deashing agent on the surface of coal particles, and the degree of wetting directly affects the interfacial mass transfer resistance. The smaller the solid-liquid interfacial tension, the smaller the wetting angle, the easier it is for the deashing agent to spread on the surface of coal particles, and the smaller the interfacial mass transfer resistance, that is:

[0057] 3) Ash in coal exists in three different forms: free, encapsulated, and lattice-like. Significant differences exist in the interfacial tension and wetting angle between these different ash forms and the deashing agent. Therefore, it is necessary to introduce a weighting factor for the ash occurrence form. The mass transfer resistance of ash in different forms is weighted and summed.

[0058] 4) Temperature, electric, and ultrasonic fields can significantly alter the interfacial tension and wetting angle of solids and liquids, therefore, it is necessary to introduce a multi-field coupled interfacial tension correction term. and multi-field coupling wetting angle correction term This study quantitatively describes the effect of multi-field coupling on interfacial mass transfer resistance.

[0059] Based on the above analysis, and considering the effective diffusion coefficient... and interface boundary layer thickness The final calculation model for the interfacial mass transfer resistance coefficient is derived as follows: (1) in, The mass transfer resistance coefficient at the coal-based hard carbon-deashing agent interface, with dimensions of The output value calculated by this formula. The effective diffusion coefficient of the deashing agent in the pores of coal-based hard carbon is given by the dimensionless method. The results were determined through a constant pressure osmosis experiment. Assign a number to the ash content storage format. Represents free-state ash. Indicates the ash content in the encapsulated state. This represents lattice-state ash content. For the first The weighting factor for the ash occurrence forms, dimensionless, was determined by quantitative analysis using XRD and SEM, and satisfies [the following criteria]. . The solid-liquid interfacial tension under multi-field coupling has dimensions of The temperature was determined by the hanging drop method. electric field strength and ultrasonic power density The function. The solid-liquid interfacial tension under normal temperature and pressure without external field, with dimensions of The determination was performed using the standard hanging drop method. For the first The solid-liquid wetting angle corresponding to the ash occurrence form, with the dimension of degrees (°), is measured by a contact angle meter and is related to temperature. electric field strength and ultrasonic power density The function. The thickness of the solid-liquid interface boundary layer, with dimensions of The measurements were taken using a laser Doppler velocimeter (LDV).

[0060] Left side The dimensions are The total dimensions on the right are It is exactly the same as the left side.

[0061] This breakthrough represents the first quantitative leap from the microscopic ash occurrence characteristics of coal-based hard carbon feedstocks to the macroscopic interfacial mass transfer process, solving the industry-wide challenge of existing processes being unable to provide personalized mass transfer control for different coal types and ash occurrence forms. The calculated interfacial mass transfer resistance coefficient is... It is the core input parameter for subsequent ash ion migration flux prediction models.

[0062] S3. Prediction of directional migration flux of ash ions: Based on the Nernst-Planck equation, a multi-field coupled directional migration flux prediction model for ash ions is constructed by introducing a thermal diffusion term for the temperature field, an enhanced term for ultrasonic cavitation effect, and a correction term for interfacial mass transfer resistance, and quantitatively predicts the directional migration flux of different types of ash ions. The Nernst-Planck equation is the fundamental equation describing the migration of charged ions under the combined influence of a concentration gradient and a potential gradient. The original formula is:

[0063] in, For the first The migration flux of seed ions, For the first The diffusion coefficient of ash ions. For concentration gradient, The number of ions. It is Faraday's constant. The gas constant is Thermodynamic temperature For the potential gradient, The velocity is the liquid phase flow rate.

[0064] The original Nernst-Planck equation only considers the effects of concentration and potential gradients on ion migration, failing to describe the synergistic migration effect under multi-field coupling (temperature field + electric field + ultrasonic field), and also neglecting the limiting effect of solid-liquid interface mass transfer resistance on ion migration flux. This invention improves the original equation through the following steps: 1) Introducing the thermal diffusion term in the temperature field (Sorett effect): A temperature gradient causes the thermal diffusion migration of ions, and the thermal diffusion flux is proportional to the temperature gradient, i.e.:

[0065] in, is the Soret coefficient.

[0066] 2) Introducing an enhanced term for ultrasonic cavitation effect: The microjets and shock waves generated by ultrasonic cavitation can significantly enhance the convective migration of ions. The enhanced ultrasonic flux is proportional to the ultrasonic power density, i.e.:

[0067] in, The ultrasonic cavitation efficiency coefficient is given. This represents the ultrasonic power density.

[0068] 3) Introducing an interfacial mass transfer resistance correction term: The solid-liquid interfacial mass transfer resistance restricts the migration of ions from the interior of coal particles to the liquid phase, therefore, an interfacial mass transfer resistance correction coefficient needs to be introduced. The total migration flux is corrected as follows:

[0069] in, The convective mass transfer coefficient, The interfacial mass transfer resistance coefficient is calculated using Formula 1.

[0070] 4) The thermal diffusion term, ultrasonic cavitation enhancement term, and interfacial mass transfer resistance correction term are introduced into the original Nernst-Planck equation, and after merging and rearranging, the final prediction model for the directional migration flux of ash ions under multi-field coupling is obtained, as follows: (2) in, For the first The directional migration flux of ash ions, with dimensions of The output value calculated by this formula. This is the interfacial mass transfer resistance correction coefficient, dimensionless, derived from the formula. The calculation yielded, where From Formula 1, The convective mass transfer coefficient was determined experimentally. For the first The diffusion coefficient of ash ions in the deashing agent, with dimensions of _____ This can be determined by consulting an electrochemical handbook or through experimental testing. For the first The concentration gradient of ash ions, with dimensions of The determination was made through multi-point sampling and ICP-OES analysis. For the first The charge number of the ash ion is dimensionless and determined based on the chemical composition of the ion. Faraday's constant is a physical constant. . For gas constants, physical constants, . The thermodynamic temperature of the reaction system has dimensions of . , measured in real time by thermocouples. Let be the electric field intensity gradient, with dimensions . The electric field strength was measured using an electric field strength meter. Let be the Soret coefficient, with dimensions . The results were determined through a thermal diffusion cell experiment. For temperature gradient, the dimension is Calculations are performed using multi-point thermocouple measurements. The ultrasonic cavitation efficiency coefficient has dimensions of . , as determined by experiments. The ultrasonic power density has the following dimensions: It is set through the ultrasonic generator. For the first The bulk concentration of ash ions, in units of , is . The results were determined by ICP-OES analysis. The liquid flow rate of the deashing agent is expressed in units of _____. , measured by a flow meter.

[0071] Left side The dimensions are The total dimensions on the right are It is exactly the same as the left side.

[0072] For the first time, the synergistic enhancement effect of temperature, electric, and ultrasonic fields on ash ion migration was systematically quantified, enabling accurate prediction of the directional migration flux of different types of ash ions under multi-field coupling conditions. The calculated ash ion migration flux is shown in the figure. It is the core input parameter for the subsequent calculation model of the deashing reaction kinetic rate constant.

[0073] S4. Calculation of the kinetic rate constant of the deashing reaction: Based on the Arrhenius equation, the multi-field coupling synergistic effect coefficient, ash ion migration restriction factor and ash inclusion breakage probability term are introduced to construct a coupling model between the kinetic rate constant of the deashing reaction and process parameters, and to quantitatively calculate the kinetic rate constant of the deashing reaction under multi-field coupling conditions. The Arrhenius Equation: The fundamental equation describing the relationship between the rate constant of a chemical reaction and temperature. The original formula is as follows:

[0074] in, The reaction rate constant is... Pre-exponential factor, The activation energy of the reaction. The gas constant is... It is the thermodynamic temperature.

[0075] The original Arrhenius equation can only describe the intrinsic reaction rate constant under a single temperature field, failing to reflect the synergistic catalytic effect of multi-field coupling on the deashing reaction, and also neglecting the limiting effect of ash ion migration rate on the reaction rate and the influence of ash occurrence form on reaction activity. This invention improves the original equation through the following steps: 1) Introduce the multi-field coupling synergistic effect coefficient Multi-field coupling can increase the reaction rate constant by lowering the reaction activation energy, i.e.:

[0076] in, The apparent reaction activation energy under multi-field coupling, This indicates a multi-field synergistic enhancement effect.

[0077] 2) Introduce ash ion migration restriction factor The deashing reaction is a mass transfer-reaction coupled process. When the reaction rate is greater than the ion migration rate, the reaction rate is determined by the ion migration rate. Therefore, the reaction rate constant cannot exceed the limit determined by the ion migration rate, i.e.:

[0078] in, The ash ion migration flux calculated using Formula 2 is... The limiting migration flux was determined experimentally.

[0079] 3) Introducing a reactivity correction term for ash occurrence forms: Ash in different occurrence forms has different reactivity. Free ash has the highest reactivity, encapsulated ash can only participate in the reaction after the inclusions are broken, and lattice-state ash has the lowest reactivity. Therefore, a weighting factor for ash occurrence forms is introduced. , probability of fragmentation of encapsulated ash And the lattice-state ash reactivity correction coefficient The reactivity of different forms of ash was modified.

[0080] 4) Introducing the above correction terms into the original Arrhenius equation and combining and rearranging them, we obtain the final coupled model of the deashing reaction kinetic rate constant and process parameters, as follows: (3) in, Let be the kinetic rate constant of the deashing reaction under multi-field coupling, with dimensions of . The output value calculated by this formula. The intrinsic reaction rate constant under normal temperature and pressure without external field has dimensions of . It was obtained through thermogravimetric analysis (TGA) experiments combined with the original Arrhenius equation. The coefficient for the multi-field coupling synergistic effect is dimensionless and obtained through experimental fitting; it is a factor of temperature. electric field strength and ultrasonic power density The function. The migration restriction factor for ash ions is dimensionless and is given by the formula. Calculations show that The limiting migration flux was determined experimentally. is a weighting factor for the ash content in the free state, encapsulated state, and lattice state. It is dimensionless and has the same definition and acquisition method as in Formula 1. The probability of ultrasonic fragmentation of encapsulated ash is dimensionless and determined by SEM image analysis. It is positively correlated with ultrasonic power density and ultrasonic treatment time. The is the dimensionless correction coefficient for the reactivity of lattice-state ash, determined experimentally. The intrinsic activation energy of the deashing reaction has dimensions of It was obtained through TGA experiments combined with the original Arrhenius equation. Herein lies the gas constant and the thermodynamic temperature.

[0081] Left side The dimensions are The total dimensions on the right are It is exactly the same as the left side.

[0082] For the first time, macroscopic process parameters, microscopic ion migration processes, and ash occurrence modes are organically combined to accurately calculate the kinetic rate constant of the deashing reaction under multi-field coupling conditions. The calculated reaction rate constant is... It is the core input parameter of the subsequent multi-objective optimization and control model of process parameters.

[0083] S5. Multi-objective optimization and control of process parameters: Based on Pareto optimal solution theory and response surface methodology, a multi-objective optimization and control model for deep deashing process parameters, including deashing depth and hard carbon structure damage, is constructed to obtain the optimal combination of process parameters (temperature, electric field strength, ultrasonic power density, and reaction time). Pareto Optimality Theory: In multi-objective optimization problems, the solution is Pareto optimal when no objective can be improved without harming the others.

[0084] Response surface methodology (RSM) is an experimental design and optimization method that uses a multinomial regression model to approximate the relationship between independent and dependent variables.

[0085] Existing optimization methods for coal-based hard carbon deashing processes often employ single-factor experimental approaches, which cannot simultaneously address the conflicting objectives of "maximizing deashing depth" and "minimizing hard carbon structural damage," resulting in often biased optimization outcomes. This invention constructs a multi-objective optimization control model through the following steps: 1) Relationship between deashing depth and reaction kinetics: Deashing depth Deashing depth is defined as the percentage of ash removed from the total ash mass in the raw coal. According to first-order reaction kinetics, the deashing depth is related to the reaction rate constant. and reaction time The relationship is:

[0086] 2) Relationship between hard carbon structural damage degree and process parameters: Hard carbon structural damage degree Defined as the rate of change of the structural parameters of hard carbon after deashing relative to the raw coal, it is positively correlated with the intensity of process parameters (temperature, electric field strength, ultrasonic power density, and reaction time). To eliminate the influence of different dimensions and value ranges of process parameters, each process parameter is normalized, and weighting coefficients are introduced. Quantitatively describe the contribution of different process parameters to the degree of structural damage, namely:

[0087] in, , , , These are the value ranges for each process parameter.

[0088] 3) Construct a dual-objective optimization function: with the optimization objectives of "maximizing deashing depth" and "minimizing hard carbon structure damage", namely:

[0089] 4) Introduce a trade-off coefficient ( The bi-objective optimization problem is transformed into a single-objective optimization problem, and a comprehensive optimization objective function is constructed. .

[0090] when When, it indicates that priority should be given to ensuring the deashing depth; when When this is the case, it indicates that the hard carbon structure should be protected first.

[0091] (4) in, To comprehensively optimize the objective function, which is dimensionless, the maximum value of the calculated output value of this formula corresponds to the optimal combination of process parameters. This is a dimensionless coefficient that represents the trade-off between deashing depth and structural damage. It is manually set based on product quality requirements and its value ranges from [value range missing]. . Let be the kinetic rate constant for the deashing reaction, with dimensions . . The reaction time has dimensions of . The parameters to be optimized have a range of values. . The weighting coefficients for temperature, electric field strength, ultrasonic power density, and reaction time on the damage degree of hard carbon structures are dimensionless and determined experimentally using Raman spectroscopy, specific surface area analysis, and X-ray photoelectron spectroscopy (XPS). . The reaction temperature and its range are given, with dimensions of _____. Parameters to be optimized. The electric field strength and its range of values ​​are given by the dimensionless standard. Parameters to be optimized. Ultrasonic power density and its range, with dimensions of Parameters to be optimized.

[0092] Left side The terms on the right are dimensionless; all terms on the right side are dimensionless, which is completely consistent with the terms on the left side.

[0093] In one embodiment, the comprehensive optimization objective function is solved as follows: taking temperature, electric field strength, ultrasonic power density, and reaction time as factors, 27 sets of multi-field coupled deashing experiments are arranged using Box-Behnken response surface design. The deashing depth and hard carbon structure damage of each set of experiments are measured. The least squares method is used to fit a quadratic polynomial response surface model of the comprehensive optimization objective function with respect to the four factors, and the variance analysis of the response surface model is performed to test the significance. The maximum value of the response surface model is solved within its respective value range. The combination of factor levels corresponding to the maximum value is the optimal combination of process parameters. The values ​​of each factor are as follows: reaction temperature 40~90℃, electric field strength 10~100V / m, ultrasonic power density 100~1000W / m³, and reaction time 1~6h. In this embodiment, the trade-off coefficient is 0.6, that is, the deashing depth is given priority. The weighting coefficients are calibrated by Raman spectroscopy, specific surface area analysis and XPS experiment as ω1=0.42, ω2=0.18, ω3=0.25 and ω4=0.15.

[0094] For the first time, a dual-objective optimization model based on deashing reaction kinetics was constructed, which can simultaneously take into account the deashing depth and the integrity of the hard carbon structure. The optimal combination of process parameters obtained by the solution can directly guide industrial production and realize the precise control of coal-based hard carbon deep deashing process.

[0095] S6. Multi-field coupling deep deashing experiment: Based on the combination of process parameters obtained in step S5, determine the reaction temperature, electric field strength, ultrasonic power density and reaction time used in the deep deashing process of coal-based hard carbon. The pretreated coal-based hard carbon raw material and deashing agent are added to the multi-field coupling reaction device according to the set solid-liquid ratio. The multi-field coupling reaction device is started, and temperature field, electric field and ultrasonic field are applied respectively according to the process parameter combination, so that the coal-based hard carbon raw material undergoes a deep deashing reaction under the combined action of temperature field, electric field and ultrasonic field. During the deashing reaction, the reaction temperature, electric field strength, and ultrasonic power density are monitored so that the process parameters are combined according to the process parameters to act on the coal-based hard carbon deashing process. Among them, the temperature field is used to affect the deashing reaction and the thermal diffusion and migration of ions, the electric field is used to promote the directional migration of charged ash ions, and the cavitation effect generated by the ultrasonic field is used to enhance mass transfer and promote the exposure and migration of encapsulated ash. After the reaction time is reached, the multi-field coupling effect is stopped, the coal-based hard carbon after deashing is separated from the liquid phase, the obtained coal-based hard carbon is filtered, and washed with washing liquid until neutral to remove residual deashing agent and soluble reaction products formed during the deashing process. The washed coal-based hard carbon was dried to constant weight under vacuum drying conditions, and then carbonized under an inert atmosphere to obtain the deashed coal-based hard carbon product.

[0096] In one specific embodiment, a combined alkali-acid deashing method is adopted: the pretreated raw coal and a 20% NaOH solution are first added to a multi-field coupled reaction device at a solid-liquid ratio of 1:5. Under multi-field coupling conditions, alkali leaching is carried out for 1 hour to dissolve amphoteric and acidic ash such as SiO2 and Al2O3. After filtration and separation, the alkali-leached coal-based hard carbon raw material and a 10% HCl solution are added to the multi-field coupled reaction device at a solid-liquid ratio of 1:5. Under multi-field coupling conditions, acid leaching is carried out for 3 hours to dissolve ash such as Fe2O3, CaO, and MgO. The total reaction time for alkali leaching and acid leaching is 4 hours. Both alkali leaching and acid leaching are carried out under temperature field, electric field, and ultrasonic field coupling conditions. The reaction temperature, electric field strength, ultrasonic power density, and reaction time are set according to the process parameter combination obtained by the aforementioned model calculation and multi-objective optimization. After deashing, the coal-based hard carbon was filtered and washed until neutral, and then vacuum dried at 105℃ for 12 hours. Subsequently, under nitrogen atmosphere protection, the temperature was increased to 1100℃ at a rate of 5℃ / min, held for 2 hours, and then naturally cooled to room temperature to obtain the coal-based hard carbon product.

[0097] In another embodiment of the present invention, a coal-based hard carbon deashing control system based on multi-field coupled mass transfer kinetics is provided. This system can be used to implement the above-mentioned coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics. Specifically, the coal-based hard carbon deashing control system based on multi-field coupled mass transfer kinetics includes an ash content occurrence characteristic analysis unit, an interface mass transfer resistance calculation unit, an ion migration flux prediction unit, a reaction kinetics calculation unit, a process parameter optimization unit, and a multi-field coupled reaction device.

[0098] The ash occurrence characteristic analysis unit is used to obtain the mass fraction of free, encapsulated and lattice ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, and to determine the ash occurrence form weighting factor based on the mass fraction. The interfacial mass transfer resistance calculation unit is used to calculate the interfacial mass transfer resistance coefficient of coal-based hard carbon-deashing agent based on Fick's first law and Young's equation, according to the weighting factor of the ash occurrence morphology and the interfacial tension correction term and wetting angle correction term under the action of temperature field, electric field and ultrasonic field. The ion migration flux prediction unit is used to calculate the directional migration flux of ash ions based on the Nernst-Planck equation, according to the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interface mass transfer resistance correction term determined by the interface mass transfer resistance coefficient. The reaction kinetics calculation unit is used to calculate the deashing reaction kinetic rate constant based on the Arrhenius equation, according to the multi-field coupling synergistic effect coefficient, the ash ion migration restriction factor determined by the directional migration flux, and the ash inclusion fragmentation probability term. The process parameter optimization unit is used to perform multi-objective optimization of temperature, electric field strength, ultrasonic power density and reaction time based on Pareto optimal solution theory and response surface methodology, according to the deashing reaction kinetic rate constant, with deashing depth and hard carbon structure damage degree as optimization objectives, to obtain a combination of process parameters; A multi-field coupled reaction device is used to provide a temperature field, an electric field, and an ultrasonic field according to the combination of process parameters to deash coal-based hard carbon, and to monitor the reaction temperature, electric field strength, and ultrasonic power density.

[0099] This invention provides a terminal device comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or function. The processor described in this embodiment can be used in the operation of a coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics, including: The mass fractions of free, encapsulated, and lattice-state ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, are obtained. A weighting factor for the ash occurrence form is determined based on the mass fractions. Based on Fick's first law and Young's equation, the interfacial mass transfer resistance coefficient between coal-based hard carbon and the deashing agent is calculated using the weighting factor for the ash occurrence form and the interfacial tension and wetting angle correction terms under the influence of temperature, electric, and ultrasonic fields. Based on the Nernst-Planck equation, the ash content is calculated using the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interfacial mass transfer resistance correction term determined by the interfacial mass transfer resistance coefficient. The directional migration flux of the ash separators is determined. Based on the Arrhenius equation, the kinetic rate constant of the deashing reaction is calculated according to the multi-field coupling synergistic effect coefficient, the ash separator migration restriction factor determined by the directional migration flux, and the ash inclusion breakage probability term. Based on Pareto optimality theory and response surface methodology, and according to the kinetic rate constant of the deashing reaction, multi-objective optimization is performed on temperature, electric field strength, ultrasonic power density, and reaction time, with deashing depth and hard carbon structure damage as optimization objectives, to obtain a combination of process parameters. According to the combination of process parameters, coal-based hard carbon is deashed under the coupling conditions of temperature field, electric field, and ultrasonic field.

[0100] Please see Figure 5 The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When executed by the processor 61, the computer program 63 implements the coal-based hard carbon deashing control method based on multi-field coupled mass transfer dynamics as described in this embodiment. To avoid repetition, details are omitted here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the coal-based hard carbon deashing control system based on multi-field coupled mass transfer dynamics as described in this embodiment. To avoid repetition, details are omitted here.

[0101] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 5 This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0102] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0103] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on the computer device 60.

[0104] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0105] Please see Figure 6 The terminal device is an electronic device 600, which is manifested in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0106] The storage unit stores program code, which can be executed by the processing unit 610 to perform the steps described in the method section of this specification according to various exemplary embodiments of the present invention. For example, the processing unit 610 can perform actions such as... Figure 1 The steps are shown in the figure.

[0107] Storage unit 620 may include readable media in the form of volatile storage units, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include read-only memory (ROM) 6203.

[0108] Storage unit 620 may also include a program / utility 6204 having a set (at least one) program module 6205, such program module 6205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0109] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the multiple bus structures.

[0110] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem). This communication can be performed via input / output interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network, wide area network, and / or public network, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0111] This invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It is understood that the computer-readable storage medium here can include both built-in storage media in the terminal device and extended storage media supported by the terminal device; it can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). More specific examples of the computer-readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, portable compact disk read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0112] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium can also be any readable medium other than a readable storage medium that can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, radio frequency, etc., or any suitable combination thereof.

[0113] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0114] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor in the following steps: The mass fractions of free, encapsulated, and lattice-state ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, are obtained. A weighting factor for the ash occurrence form is determined based on the mass fractions. Based on Fick's first law and Young's equation, the interfacial mass transfer resistance coefficient between coal-based hard carbon and the deashing agent is calculated using the weighting factor for the ash occurrence form and the interfacial tension and wetting angle correction terms under the influence of temperature, electric, and ultrasonic fields. Based on the Nernst-Planck equation, the ash content is calculated using the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interfacial mass transfer resistance correction term determined by the interfacial mass transfer resistance coefficient. The directional migration flux of the ash separators is determined. Based on the Arrhenius equation, the kinetic rate constant of the deashing reaction is calculated according to the multi-field coupling synergistic effect coefficient, the ash separator migration restriction factor determined by the directional migration flux, and the ash inclusion breakage probability term. Based on Pareto optimality theory and response surface methodology, and according to the kinetic rate constant of the deashing reaction, multi-objective optimization is performed on temperature, electric field strength, ultrasonic power density, and reaction time, with deashing depth and hard carbon structure damage as optimization objectives, to obtain a combination of process parameters. According to the combination of process parameters, coal-based hard carbon is deashed under the coupling conditions of temperature field, electric field, and ultrasonic field.

[0115] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include distributed databases, etc., and are not limited thereto. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, etc., and are not limited thereto.

[0116] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0117] The method for precise control of coal-based hard carbon deep deashing process based on multi-field coupled mass transfer dynamics, as described in this invention, includes the following specific implementation steps: 1. Raw material pretreatment: The raw coal is crushed to below 200 mesh and preliminarily deashed by flotation to remove most of the free ash.

[0118] 2. Ash content characteristics analysis: XRD, SEM and EDS were used to analyze the pretreated raw coal to quantitatively determine the mass fraction of free, encapsulated and lattice ash. The solid-liquid interfacial tension under ambient temperature, pressure, and no external field was determined using the pendant drop method. The solid-liquid wetting angle corresponding to different ash storage forms was determined using a contact angle measuring instrument. .

[0119] 3. Measurement of basic parameters: The effective diffusion coefficient of the deashing agent in the pores of coal-based hard carbon was determined by constant pressure permeation experiments. ; The thickness of the solid-liquid interface boundary layer was determined using a laser Doppler velocimeter. ; In this embodiment, the determination and fitting results of the main model parameters are as follows: the mass fractions of ash in the free state, encapsulated state, and lattice state are 0.55, 0.30, and 0.15, respectively; the effective diffusion coefficient is 3.2 × 10⁻⁶. -9 m 2 / s; the solid-liquid interface boundary layer thickness is 1.8×10 -5 m; the intrinsic reaction rate constant is 2.3 × 10⁻⁶. -4 s -1 The intrinsic activation energy is 48 kJ / mol; the Soret coefficient is 0.012 K. -1 The ultrasonic cavitation efficiency coefficient is 1.5 × 10⁻⁶. -6 m 3 / (W·s); the convective mass transfer coefficient is 5.6×10 -5 m / s; the correction coefficient for the reactivity of lattice-state ash is 0.15; the ultrasonic breakage probability of encapsulated ash is 0.70; the solid-liquid interfacial tension at room temperature and pressure without external field is 0.052 N / m, and the solid-liquid wetting angle is 38°; the multi-field coupling synergistic effect coefficient is obtained by least-squares fitting of the deashing rate experimental data under different temperatures, electric field strengths, and ultrasonic power densities. Substituting the above parameters into Equations 1 to 3, the values ​​at 65℃, 50 V / m, and 500 W / m are calculated. 3 The kinetic rate constant for the deashing reaction under the given conditions is approximately 2.7 × 10⁻⁶. -4 s -1The theoretical deashing depth corresponding to a reaction time of 4 hours is approximately 0.98. Substituting these values ​​into the comprehensive optimization objective function shown in Formula 4 and solving for the maximum value yields the optimal combination of process parameters. The above values ​​are the calibration results of this embodiment. For different coal types or different deashing agent systems, recalibration can be performed according to the same experimental procedure.

[0120] The intrinsic reaction rate constant was determined by thermogravimetric analysis. and intrinsic reaction activation energy ; The diffusion coefficients of different ash ions were determined using electrochemical handbooks or experiments. and charge number ; The Solette coefficient was determined by a thermal diffusion cell experiment. ; The ultrasonic cavitation efficiency coefficient was determined experimentally. Convection mass transfer coefficient And the lattice-state ash reactivity correction coefficient ; The weighting coefficients of various process parameters on the damage degree of hard carbon structure were determined by Raman spectroscopy, specific surface area analysis, and XPS experiments. .

[0121] 4. Measurement of multi-field coupling parameters: at different temperatures electric field strength and ultrasonic power density Under the conditions, the interfacial tension of the solid and liquid was measured respectively. Solid-liquid wetting angle and multi-field coupling synergistic effect coefficient And obtained through experimental fitting The function expression.

[0122] 5. Formula calculation and parameter optimization: Substitute the parameters measured in steps 2 and 4 into Equation 1 to calculate the interfacial mass transfer resistance coefficient under different multi-field coupling conditions. ; Will Substituting other relevant parameters into Formula 2, the directional migration flux of different ash ions is calculated. ; Will Substituting other relevant parameters into Equation 3, the kinetic rate constant of the deashing reaction under different multi-field coupling conditions is calculated. ; Will Substitute other relevant parameters into Formula 4, and set the trade-off coefficients according to product quality requirements. Solve the comprehensive optimization objective function The maximum value is used to obtain the optimal combination of process parameters. .

[0123] 6. Multi-field coupling deep deashing experiment: The pretreated raw coal and deashing agent are added to the multi-field coupling reaction device at a certain solid-liquid ratio. The reaction temperature, electric field strength, ultrasonic power density and reaction time are set according to the optimal process parameter combination to carry out the deep deashing experiment.

[0124] 7. Post-processing: After deashing, the coal-based hard carbon is filtered, washed until neutral, dried to constant weight in a vacuum drying oven, and then carbonized under an inert atmosphere to obtain the final coal-based hard carbon product.

[0125] 8. Product performance testing: The ash content of hard carbon products is determined by ICP-OES, the structural parameters of hard carbon are determined by Raman spectroscopy and specific surface area analyzer, and the electrochemical performance of hard carbon is determined by constant current charge-discharge test.

[0126] To verify the beneficial effects of the present invention, the following comparative experiments were conducted: Shanxi Datong bituminous coal was selected as the experimental raw material, and its industrial analysis and elemental analysis results are shown in Table 1.

[0127] Table 1. Industrial and elemental analysis of Datong bituminous coal (industrial analysis is on an air-dried basis, elemental analysis is on a dry ash-free basis).

[0128] The device employs a self-developed multi-field coupling reaction device, which can simultaneously provide temperature, electric, and ultrasonic fields, and can monitor parameters such as reaction temperature, electric field strength, ultrasonic power density, and pH value in real time.

[0129] Control group (traditional acid-base deashing method) The raw coal is crushed to below 200 mesh, and a 20% NaOH solution is added at a solid-liquid ratio of 1:5. The mixture is stirred and reacted at 80°C for 4 hours. Filter and wash until neutral, add 15% HCl solution at a solid-liquid ratio of 1:5, and stir at 80°C for 4 hours. Filter and wash until neutral, then vacuum dry at 105℃ for 12 hours; Under nitrogen atmosphere protection, the temperature was raised to 1100℃ at a rate of 5℃ / min, held for 2 hours, and then naturally cooled to room temperature to obtain the control group hard carbon product.

[0130] According to the specific embodiments described in this invention, the ash content characteristics and basic parameters of Datong bituminous coal were analyzed and determined. The optimal combination of process parameters was obtained: reaction temperature electric field strength Ultrasonic power density reaction time ; The pretreated raw coal and a 20% NaOH solution were added to a multi-field coupling reaction device at a solid-liquid ratio of 1:5. The coal was alkali-leached for 1 hour under multi-field coupling conditions of 65℃, 50V / m, and 500W / m³. After filtration and separation, a 10% HCl solution was added and acid-leached for 3 hours under the same multi-field coupling conditions. The total reaction time for alkali-leaching and acid-leaching was 4 hours, which is the optimal process parameter combination. Filter and wash until neutral, then vacuum dry at 105℃ for 12 hours; The experimental group of hard carbon products was obtained by carbonization under the same carbonization conditions as the control group.

[0131] I. Comparison of Ash Content The ash content of the hard carbon products in the control and experimental groups was determined by ICP-OES, and the results are shown in Table 2. Table 2 Ash content of hard carbon products in control and experimental groups

[0132] As shown in Table 2, the total ash content of the control group hard carbon product was 1.34%, while the total ash content of the experimental group hard carbon product was only 0.067%, indicating a significant improvement in deashing depth. In particular, for the difficult-to-remove SiO2 and Al2O3, the removal rate of this invention was increased by more than 94%, fully demonstrating the excellent removal effect of this invention on both encapsulated and lattice-state ash.

[0133] The contents of SiO2, Al2O3, Fe2O3, CaO, MgO and total ash in the control group hard carbon product obtained by the traditional acid-base combined deashing method and the experimental group hard carbon product obtained by the multi-field coupling precise control deashing method of this invention were determined by ICP-OES.

[0134] Please see Figure 2 The ash content test results are shown in Table 2 of the above embodiments. ICP-OES was used to test the hard carbon products of the control group and the experimental group. The total ash content of the control group was 1.34%, while the total ash content of the experimental group was reduced to 0.067%. The residual contents of SiO2, Al2O3, Fe2O3, CaO, and MgO in the experimental group were significantly lower than those in the control group, indicating that the present invention can improve the deep deashing effect of coal-based hard carbon.

[0135] II. Comparison of Structural Parameters The structural parameters of the hard carbon products in the control and experimental groups were determined using Raman spectroscopy and a specific surface area analyzer. The results are shown in Table 3. Table 3 Structural parameters of hard carbon products in the control and experimental groups

[0136] in, The ratio of the D peak to the G peak in the Raman spectrum represents the intensity. A higher ratio indicates a higher degree of disorder and more severe structural damage in hard carbon. Table 3 shows that the hard carbon products in the control group... The ratio increased from 0.82 in raw coal to 1.35, and the specific surface area increased from 5.2 m². 2 / g increased sharply to 128.6m 2 / g indicates that the traditional acid-base combined deashing method causes serious damage to the hard carbon structure. Meanwhile, the hard carbon products from the experimental group... The ratio is only 0.95, and the specific surface area is only 23.4 m². 2 / g, the structural damage was reduced by more than 75%, which fully demonstrates that the present invention can effectively protect the structural integrity of hard carbon while ensuring the deashing depth.

[0137] Please see Figure 3 (a) Raw coal The control group had a concentration of 0.82, while the experimental group's concentration increased to 1.35 after traditional acid-base deashing, whereas the experimental group's concentration was only 0.95. This was due to... The larger the value, the higher the degree of disorder in the carbon material. Therefore, the experimental group values ​​are closer to those of raw coal, indicating that the present invention can reduce the damage to the coal-based carbon structure caused by the deashing process.

[0138] Please see Figure 3 (b) The specific surface area of ​​raw coal is 5.2 m². 2 / g, the control group increased to 128.6m 2 / g, while the experimental group only had 23.4m 2 / g; Please see Figure 3 (c) The pore volume of raw coal is 0.012 cm³. 3 / g, the control group increased to 0.256cm 3 / g, while the experimental group was 0.045cm 3 / g.

[0139] Compared with the control group, the experimental group showed a significantly smaller change in specific surface area and pore volume.

[0140] The above results show that the present invention uses a dual-objective optimization mechanism of maximizing deashing depth and minimizing hard carbon structure damage to determine temperature, electric field strength, ultrasonic power density and reaction time, avoiding the need to simply increase temperature, increase acid-base interaction intensity or extend reaction time to achieve deep deashing, and can better maintain the integrity of hard carbon structure while effectively removing ash.

[0141] III. Comparison of Electrochemical Performance Using CR2032 button cells with sodium metal as the counter electrode and 1 mol / L NaClO4 / EC+DMC (volume ratio 1:1) as the electrolyte, constant current charge-discharge tests were conducted within the voltage range of 0.01~2.5V. The electrochemical performance of the hard carbon products in the control and experimental groups was measured, and the results are shown in Table 4. Table 4 Electrochemical performance of hard carbon products in the control and experimental groups (0.1C rate)

[0142] As shown in Table 4, the experimental group of hard carbon products exhibited significantly better first-discharge specific capacity, first-charge specific capacity, first-coulombic efficiency, and cycle stability than the control group. In particular, the first-coulombic efficiency increased from 78.0% to 86.0%, and the capacity retention rate after 50 cycles increased from 82.3% to 94.5%, fully demonstrating that the low-ash, high-structural-integrity hard carbon products possess superior electrochemical performance.

[0143] Please see Figure 4 The figure shows a comparison of the electrochemical performance of the control and experimental groups of hard carbon products in this invention, corresponding to the electrochemical performance test results shown in Table 4 of the above embodiments. At a 0.1C rate, the initial discharge specific capacity and initial charge specific capacity of the experimental group were 368.2 mAh / g and 316.7 mAh / g, respectively, higher than the 325.6 mAh / g and 254.0 mAh / g of the control group. The initial coulombic efficiency of the experimental group reached 86.0%, and the capacity retention rate after 50 cycles reached 94.5%, higher than the 78.0% and 82.3% of the control group, respectively. This indicates that the low-ash, high-structural-integrity coal-based hard carbon obtained by this invention has good reversible capacity, initial coulombic efficiency, and cycle stability.

[0144] The comparative experimental results above demonstrate that the precise control method for deep deashing of coal-based hard carbon using multi-field coupled mass transfer kinetics, as described in this invention, reduces the total ash content of the hard carbon product from 1.34% to 0.067%, increases the relative ash removal rate by 95.0%, reduces the structural damage of hard carbon by more than 75%, improves the initial coulombic efficiency of the hard carbon product by 8 percentage points, and significantly enhances cycle stability compared to the traditional acid-base combined deashing method. This invention achieves precise control of the deep deashing process for coal-based hard carbon, resolving the contradiction between "incomplete deashing" and "severe structural damage" in existing technologies, and has significant industrial application value.

[0145] In summary, this invention presents a coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics. This method overcomes the traditional reliance on empirical adjustments of acid / alkali concentration, temperature, and reaction time in coal-based hard carbon deashing, integrating ash occurrence morphology, interfacial mass transfer, ash ion migration, and deashing reaction kinetics into a unified process control system. Addressing the differences in mass transfer conditions and reactivity among free, encapsulated, and lattice-state ash, the method improves the process's adaptability to different raw materials through ash occurrence morphology weighting and interfacial mass transfer resistance calculation. Utilizing temperature, electric, and ultrasonic fields to jointly regulate ion migration and reaction processes helps reduce mass transfer limitations and improve the removal capacity of encapsulated and lattice-state ash. Furthermore, the method employs a dual-objective optimization of deashing depth and hard carbon structural damage to determine process parameters, avoiding over-processing caused by solely aiming to increase the degree of deashing. In the comparative experiment, the total ash content of the experimental group decreased from 1.34% in the traditional process to 0.067%, the initial coulombic efficiency increased from 78.0% to 86.0%, and the capacity retention rate after 50 cycles increased from 82.3% to 94.5%, indicating that the scheme can maintain a good hard carbon structure and electrochemical performance while improving the degree of deashing.

[0146] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for controlling coal-based hard carbon deashing based on multi-field coupled mass transfer kinetics, characterized in that, Includes the following steps: The mass fractions of free, encapsulated, and lattice-state ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, are obtained, and the weighting factor of ash occurrence form is determined based on the mass fractions. Based on Fick's first law and Young's equation, the mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface is calculated according to the weighting factor of the ash occurrence morphology and the interfacial tension correction term and wetting angle correction term under the action of temperature field, electric field and ultrasonic field. Based on the Nernst-Planck equation, the directional migration flux of ash ions is calculated according to the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interface mass transfer resistance correction term determined by the interface mass transfer resistance coefficient. Based on the Arrhenius equation, the deashing reaction kinetic rate constant is calculated according to the multi-field coupling synergistic effect coefficient, the ash ion migration restriction factor determined by the directional migration flux, and the ash inclusion breakage probability term. Based on Pareto optimality theory and response surface methodology, and taking the deashing reaction kinetic rate constant as the optimization objective, the temperature, electric field strength, ultrasonic power density and reaction time are optimized in multiple objectives to obtain the process parameter combination. According to the combination of process parameters, coal-based hard carbon is deashed under the coupling conditions of temperature field, electric field and ultrasonic field.

2. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, Obtaining the ash content morphology weighting factor includes: Crushing, screening and pretreatment of coal-based hard carbon raw materials; X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were used to analyze the pretreated coal-based hard carbon raw materials to determine the mass fractions of free ash, encapsulated ash, and lattice ash, and to determine the corresponding ash occurrence format weighting factor based on each mass fraction.

3. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, The mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface is calculated according to the following formula: in, The mass transfer resistance coefficient at the coal-based hard carbon-deashing agent interface; The effective diffusion coefficient of the deashing agent in the pores of coal-based hard carbon; Assign a number to the ash content storage format. Represents free-state ash. Indicates the ash content in the encapsulated state. Represents lattice-state ash content; For the first The weighting factor of the ash content distribution form, and ; For temperature electric field strength and ultrasonic power density Solid-liquid interfacial tension under action; The solid-liquid interfacial tension is defined as the solid-liquid interfacial tension under normal temperature, pressure, and no external field conditions. For the first Ash occurrence forms at temperature electric field strength and ultrasonic power density Solid-liquid wetting angle under action; The thickness of the solid-liquid interface boundary layer.

4. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, No. The directional migration flux of ash ions is calculated using the following formula: in, For the first Directed migration flux of ash ions; This is the correction factor for interfacial mass transfer resistance; For the first The diffusion coefficient of ash ions in the deashing agent; For the first Bulk concentration of ash ions; For the first The charge number of the ash ions; It is Faraday's constant; It is the gas constant; Thermodynamic temperature; It is the electric potential; The Soret coefficient; For temperature gradient; The ultrasonic cavitation efficiency coefficient; Ultrasonic power density; The flow rate of the deashing agent in the liquid phase is denoted as ...

5. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, The kinetic rate constant of the deashing reaction is calculated according to the following formula: in, The kinetic rate constant for the deashing reaction under multi-field coupling conditions; It is the intrinsic reaction rate constant under normal temperature, normal pressure, and no external field conditions; For temperature electric field strength and ultrasonic power density The corresponding multi-field coupling synergistic effect coefficient; It is the migration restriction factor for ash ions; This represents the ultimate migration flux; These are the weighting factors for free ash, encapsulated ash, and lattice ash, respectively. The probability of ultrasonic fragmentation of encapsulated ash; This is the correction coefficient for the reactivity of lattice-state ash. This is the intrinsic activation energy of the deashing reaction; It is the gas constant; It is the thermodynamic temperature.

6. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, The comprehensive objective function of the multi-objective optimization is: in, To comprehensively optimize the objective function, the temperature corresponding to its maximum value is... electric field strength Ultrasonic power density and reaction time The combination of these is the process parameter combination; This is a trade-off coefficient between deashing depth and hard carbon structural damage. ; The kinetic rate constant of the deashing reaction is denoted as . and , and , and , and These represent the ranges of values ​​for temperature, electric field strength, ultrasonic power density, and reaction time, respectively. These are the weighting coefficients for temperature, electric field strength, ultrasonic power density, and reaction time on the damage degree of hard carbon structures, respectively. .

7. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, When calculating the mass transfer resistance coefficient of the coal-based hard carbon-deashing agent interface, the effective diffusion coefficient of the deashing agent in the pores of coal-based hard carbon was determined by constant pressure permeation experiment, and the thickness of the solid-liquid interface boundary layer was determined by laser Doppler velocimeter. When calculating the directional migration flux of the ash ions, the diffusion coefficient and charge number of the ash ions are determined by experiments or electrochemical manuals, the Solette coefficient is determined by thermal diffusion cell experiments, and the ultrasonic cavitation efficiency coefficient and convective mass transfer coefficient are determined by experiments. In calculating the kinetic rate constant of the deashing reaction, the intrinsic reaction rate constant and intrinsic activation energy were determined by thermogravimetric analysis, the ultrasonic breakage probability of encapsulated ash was determined by scanning electron microscopy image analysis, and the reactivity correction coefficient of lattice ash was experimentally determined. In the aforementioned multi-objective optimization, the weighting coefficients of temperature, electric field strength, ultrasonic power density, and reaction time on the damage degree of hard carbon structures were determined by Raman spectroscopy, specific surface area analysis, and X-ray photoelectron spectroscopy experiments.

8. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, Under different temperatures, electric field strengths, and ultrasonic power densities, the solid-liquid interfacial tension, solid-liquid wetting angle, and multi-field coupling synergistic effect coefficient were measured. The functional relationships between the solid-liquid interfacial tension, solid-liquid wetting angle, and multi-field coupling synergistic effect coefficient and temperature, electric field strength, and ultrasonic power density were determined by experimental fitting.

9. The coal-based hard carbon deashing control method based on multi-field coupled mass transfer kinetics according to claim 1, characterized in that, According to the aforementioned process parameter combination, the pretreated coal-based hard carbon raw material and deashing agent are added to a multi-field coupled reaction device, and the reaction temperature, electric field strength, ultrasonic power density, and reaction time are set according to the aforementioned process parameter combination for deashing treatment; the deashing treatment adopts alkali-acid combined deashing: first, the coal-based hard carbon raw material and alkali solution are subjected to alkali leaching under temperature field, electric field, and ultrasonic field coupling conditions, and after filtration and separation, the alkali-leached coal-based hard carbon raw material and acid solution are subjected to acid leaching under temperature field, electric field, and ultrasonic field coupling conditions; After deashing, the coal-based hard carbon is filtered, washed until neutral, and vacuum dried to constant weight, and then carbonized under an inert atmosphere.

10. A coal-based hard carbon deashing control system based on multi-field coupled mass transfer kinetics, characterized in that, include: The ash occurrence characteristic analysis unit is used to obtain the mass fraction of free, encapsulated and lattice ash in coal-based hard carbon raw materials, as well as the solid-liquid interfacial tension and wetting angle corresponding to each ash occurrence form, and to determine the ash occurrence form weighting factor based on the mass fraction. The interfacial mass transfer resistance calculation unit is used to calculate the interfacial mass transfer resistance coefficient of coal-based hard carbon-deashing agent based on Fick's first law and Young's equation, according to the weighting factor of the ash occurrence morphology and the interfacial tension correction term and wetting angle correction term under the action of temperature field, electric field and ultrasonic field. The ion migration flux prediction unit is used to calculate the directional migration flux of ash ions based on the Nernst-Planck equation, according to the thermal diffusion term of the temperature field, the ultrasonic cavitation effect enhancement term, and the interface mass transfer resistance correction term determined by the interface mass transfer resistance coefficient. The reaction kinetics calculation unit is used to calculate the deashing reaction kinetic rate constant based on the Arrhenius equation, according to the multi-field coupling synergistic effect coefficient, the ash ion migration restriction factor determined by the directional migration flux, and the ash inclusion fragmentation probability term. The process parameter optimization unit is used to perform multi-objective optimization of temperature, electric field strength, ultrasonic power density and reaction time based on Pareto optimal solution theory and response surface methodology, according to the deashing reaction kinetic rate constant, with deashing depth and hard carbon structure damage degree as optimization objectives, to obtain a combination of process parameters; A multi-field coupled reaction device is used to provide a temperature field, an electric field, and an ultrasonic field according to the combination of process parameters to deash coal-based hard carbon, and to monitor the reaction temperature, electric field strength, and ultrasonic power density.

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