A method for temperature control in single-plasma source processing of graphite

Abstract

This invention discloses a temperature control method for processing graphite using a single plasma source, relating to the field of plasma material processing technology. Specifically, it is a temperature control method for processing graphite using a single plasma source, including temperature, flow field, and purification rate control. Temperature control is achieved by matching the powder mass flow rate to the gas flow rate ratio at 0.005~0.05 g / s·slm, maintaining the processing temperature at 8000~10000K. Flow field control ensures that the flow field velocity fluctuation is ≤10% by maintaining the axial length of the powder feeding mechanism from the plasma source outlet at ≥5 times the outlet diameter. Purification rate control uses hydrogen or an argon + hydrogen mixture to achieve a purification rate ≥90%. The invention also involves related parameter relationships, such as temperature and gas flow rate, powder quantity and particle size, powder feeding pipe depth, gas composition, and graphite powder particle size range.

Description

Technical Field

[0001] This invention relates to the field of plasma material processing technology, specifically a temperature control method for processing graphite using a single plasma source. Background Technology

[0002] Graphite powder, a key raw material in high-end manufacturing industries such as batteries, semiconductors, and aerospace, directly determines the quality of end products through its microstructure properties (such as spheroidization rate, purity, and flowability). For example, in lithium-ion battery anode materials, graphite powder with a spheroidization rate ≥95% can significantly improve electrode filling density and cycle life; in semiconductor sintering processes, graphite powder with a purity ≥99.9% can effectively reduce the interference of impurities on conductivity and thermal stability. Plasma treatment technology, due to its ability to provide a high-temperature (6000~12000K) and high-energy-density reaction environment, has become the mainstream method for graphite powder spheroidization and purification. Its core principle is to instantly melt and spheroidize graphite powder particles through the high temperature of the plasma core region, while removing impurities such as metal oxides and moisture through volatilization or chemical reactions.

[0003] However, existing single-plasma source processing technologies face three common challenges: First, there is significant temperature fluctuation. Traditional methods control temperature solely by adjusting the plasma source power, neglecting the dynamic coupling between the powder feed rate and the plasma gas flow rate. For example, when the powder feed rate suddenly increases, the graphite powder's heat absorption rate rises. If the gas flow rate is not adjusted synchronously, this can cause a sharp drop in the temperature of the plasma core region, with fluctuations often exceeding ±1000K. This instability prevents the graphite powder from consistently remaining within its optimal spheroidization temperature range (8000~10000K), resulting in low spheroidization or uneven particle size distribution.

[0004] Second, the heating time is insufficient. In existing devices, the powder feeding mechanism is often installed near the plasma source outlet. After entering the plasma, the graphite powder is carried away from the core region by the airflow before reaching the stable high temperature zone, resulting in an effective heating time of less than 0.1 seconds. Studies have shown that graphite powder needs to be subjected to a sustained high temperature of ≥0.1 seconds to achieve complete melting and spheroidization; otherwise, only local melting occurs on the particle surface, forming irregular shapes and reducing the spheroidization rate and fluidity.

[0005] Third, the flow field uniformity is poor. After the plasma jet is ejected from the outlet, it needs to undergo an expansion-stabilization process. If the powder feeding mechanism intervenes too early, the graphite powder will enter the unstable flow field region and encounter local overheating or undercooling. This velocity fluctuation (often exceeding 10%) will cause uneven heating of the particles, with some particles over-evaporating while others do not react fully, ultimately affecting the purification rate and product consistency.

[0006] Furthermore, existing technologies lack systematic guidance for selecting plasma gas types. For example, while argon can form stable plasma, its reducing properties are weak, limiting its effectiveness in purifying graphite powder with high impurity content; nitrogen has high thermal conductivity but may introduce nitride impurities; hydrogen has strong reducing properties but requires high corrosion resistance from equipment. If the gas type does not match the process parameters, these problems will be further amplified.

[0007] In summary, existing single-plasma source processing technologies suffer from insufficient parameter synergy, making it difficult to simultaneously meet the requirements of temperature stability, heating time, and flow field uniformity, thus restricting the application of graphite powder in high-end fields. Summary of the Invention

[0008] The purpose of this invention is to provide a temperature control method for single plasma source processing of graphite. By comprehensively controlling the process, such as precisely matching the powder-to-gas flow ratio, optimizing the powder feeding position and depth, and selecting the best hydrogen-containing mixed gas, this method solves the problems of large temperature fluctuations, uneven flow field, and low purification rate in existing processes. It enables efficient spheroidization and purification of graphite powder at stable high temperatures, ensuring consistent product performance and controllable energy consumption.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a temperature control method for single plasma source processing of graphite, applied to a processing device including a plasma source and a powder feeding mechanism. By matching the ratio of the powder feeding mass flow rate to the plasma source gas flow rate to 0.005~0.05 g / s·slm, precise control of the graphite powder processing temperature is achieved, ensuring that the temperature remains stable in the range of 8000~10000K, providing a stable thermal environment for subsequent spheroidization and reaction.

[0010] Furthermore, the axial distance between the powder feeding mechanism and the plasma source outlet is set to be no less than 5 times the plasma source outlet diameter, with the diameter ranging from 10 to 50 mm. This effectively suppresses flow field velocity fluctuations and ensures that the flow field uniformity is within 10%.

[0011] Furthermore, hydrogen or a mixture of hydrogen and argon is used as the working gas. By utilizing the reducing properties of hydrogen, impurities in the graphite powder are effectively removed, achieving the technical goal of a graphite powder purification rate of not less than 90%.

[0012] Furthermore, the actual temperature of the plasma region is linearly positively correlated with the input plasma source gas flow rate, specifically satisfying T = 4500 + 75 × The calculation model of (K) allows for linear control of the processing temperature by adjusting the gas flow rate.

[0013] Furthermore, the powder mass flow rate is related to the particle size parameters of the graphite powder to be processed, and must meet the following requirements. The constraint condition of ≤0.01×d (g / s) is used to prevent large powder particles from being insufficiently melted or clumped due to excessive feeding per unit time.

[0014] Furthermore, the upper limit of the plasma source's operating power is set to within 50kW. This low-power design can match the continuous powder feeding requirements within the range of 0~1g / s, reducing equipment energy consumption and operating costs while ensuring processing effectiveness.

[0015] Furthermore, the residence time of graphite powder in the high-temperature region of the plasma core is strictly controlled, and the heating time is set to be no less than 0.1 seconds to ensure that the powder particles can fully absorb heat and complete the transformation of spheroidization morphology.

[0016] Furthermore, the depth of the powder feeding pipe extending into the plasma flame region is limited to no more than half the diameter of the plasma torch outlet, in order to avoid the powder feeding pipe obstructing or interfering with the high-speed airflow and to maintain a stable flow field.

[0017] Furthermore, a mixture of argon and hydrogen is preferably used as the working medium, wherein the volume fraction of hydrogen in the mixture is controlled between 5% and 15%, so as to synergistically improve the spheroidization rate and material purity of graphite powder.

[0018] Furthermore, the particle size range of the graphite powder raw material to be processed covers 0~100μm, and strict adherence to the powder feeding process is required. The mass flow rate ≤ 0.01d (g / s) is matched with the particle size to ensure the consistency of the processing quality of powders with different particle sizes.

[0019] This invention provides a temperature control method for processing graphite using a single plasma source, which has the following beneficial effects: 1. By limiting the powder delivery quality flow rate ( ) and plasma source gas flow rate ( With a ratio of 0.005 to 0.05 g / s·slm, this method successfully locked the processing temperature of graphite powder within a high-energy range of 8000 to 10000 K. This parameter range was not arbitrarily set, but rather based on a balance between plasma physical properties and the graphite's endothermic rate. Under these conditions, the graphite powder can rapidly reach its vaporization point for impurity separation without excessive ablation or equipment damage due to excessively high temperatures. This precise thermal environment control effectively avoids problems such as inconsistent product sphericity and large differences in crystallinity caused by temperature fluctuations in traditional processes, ensuring that each batch of processed graphite microspheres has highly consistent physicochemical properties, significantly improving product yield and industrial application value.

[0020] 2. By measuring the axial length of the powder feeding mechanism from the plasma source outlet ( ) is set to be no less than 5 times the plasma source outlet diameter ( This method constructs a fully developed and stable flow field region. This design cleverly utilizes fluid dynamics principles, significantly reducing the turbulence intensity of the high-speed plasma jet after a long buffering distance, with velocity fluctuations strictly controlled within 10%. In this highly uniform flow field, graphite powder particles can be uniformly "encapsulated" and accelerated, avoiding particle collisions and agglomeration caused by local eddies or sudden velocity changes, or situations where some particles are not fully processed due to deviation from the high-temperature zone, thus ensuring the uniformity of material distribution throughout the entire processing.

[0021] 3. By selecting hydrogen or an argon-hydrogen mixture as the working gas, this method utilizes the strong reducing properties of hydrogen to chemically react with oxides and metallic impurities in graphite at high temperatures, generating gaseous substances that are then discharged from the system. Experimental data shows that this method can achieve a graphite powder purification rate of over 90%. High-purity graphite microspheres are crucial for high-end lithium-ion battery anode materials and nuclear-grade graphite. This technology, through optimization of the gas composition, not only removes physically adsorbed impurities but also eliminates structural non-carbon elements at the molecular level, greatly expanding the application scenarios and market competitiveness of high-purity spherical graphite.

[0022] 4. This method not only provides qualitative operational guidelines but also quantitative mathematical relationships, such as the relationship between plasma temperature (T) and gas flow rate (T). The linear relationship between T = 4500 + 75 × m² (K) and the powder feeding rate ( The constraint relationship between particle size (d) and gas type is m1 ≤ 0.01 × d (g / s). These formulas transform complex physical processes into calculable and predictable engineering parameters. Operators only need to input the target particle size and gas type to deduce the optimal gas-powder ratio and temperature setpoints from the model. This data-driven control strategy reduces reliance on operator experience, significantly shortens process debugging cycles, and facilitates integration into automated production lines, laying the foundation for building smart factories under Industry 4.0 standards.

[0023] 5. This method synergistically optimizes key equipment parameters: On the one hand, limiting the plasma source power to below 50kW, while seemingly restricting the energy limit, is actually sufficient to complete the challenging spheroidization and purification tasks by increasing energy density (i.e., energy per unit volume) and optimizing gas-powder mixing efficiency, thus significantly reducing equipment manufacturing costs and operating energy consumption. On the other hand, by limiting the penetration depth of the powder feeding pipe to no more than 1 / 2 of the outlet diameter and setting the heating time of graphite powder in the core area to ≥0.1 seconds, it prevents the powder feeding pipe from melting due to overheating or coking and ensures sufficient reaction time. This design concept of "low power, high efficiency, and long life" makes the entire processing unit more stable and reliable under continuous operation, with lower maintenance costs. Attached Figure Description

[0024] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a temperature control method for processing graphite using a single plasma source. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] How to use: I. Configuration of Core Temperature Control Parameters (1) According to claims 1 and 4, the powder delivery quality flow rate must be strictly matched. With plasma source gas flow rate The ratio should be controlled within the range of 0.005~0.05 g / s·slm. The plasma temperature T and gas flow rate... The relationship is T = 4500 + 75 × (K), which can be inversely derived from this formula The required values ​​ensure that the graphite powder processing temperature remains stable within the range of 8000~10000K.

[0029] (2) According to claim 5, the powder delivery mass flow rate It needs to be coordinated with the particle size d of the graphite powder to meet the requirements. The constraint of ≤0.01×d (g / s) is used to avoid temperature fluctuations caused by excessive powder feeding.

[0030] II. Flow Field Uniformity Optimization Settings (1) According to claim 2, the installation position of the powder feeding mechanism 3 must meet the axial distance requirement. ≥5× ( (This refers to the outlet diameter of plasma source 1, ranging from 10 to 50 mm). This distance ensures that the velocity fluctuation in the plasma core region is ≤10%, while also ensuring that the heating time of the graphite powder in the core region is ≥0.1 seconds.

[0031] (2) Depth of the powder feeding tube of the powder feeding mechanism 3 penetrating into the plasma region It needs to be controlled to not exceed 1 / 2 of the plasma torch outlet diameter to avoid disturbing the flow field.

[0032] III. Gas Selection for Improving Purification Rate (1) According to claim 3, in order to improve the purification rate of graphite powder (≥90%), hydrogen or argon-hydrogen mixture should be selected as the plasma gas. If a mixture is used, the volume ratio of hydrogen should be controlled at 5%~15% to simultaneously optimize the spheroidization and purification effects.

[0033] (2) The type of gas should be flexibly selected according to the processing target: Argon is suitable for conventional spheroidization, nitrogen is suitable for rapid heating (particle size <50μm), and hydrogen is for the purification needs of high impurity graphite powder.

[0034] IV. Operating Boundary Conditions of the Unit (1) The power of plasma source 1 needs to be compatible with specifications below 50kW to support continuous conveying of powder with a flow rate of 0~1g / s.

[0035] (2) The particle size range of graphite powder should be controlled within 0~100μm, and should be related to the powder feeding flow rate. according to A ≤0.01d (g / s) relationship matching ensures uniform particle size distribution.

[0036] V. Operational Procedure Overview After starting plasma source 1, first set the gas flow rate according to the target temperature (8000~10000K). Press again / =0.005~0.05 Calculate the powder delivery flow rate Adjust the powder feeding mechanism to 3... ≥5× The axial position of the gas and the selection of a suitable gas type are crucial. During operation, continuous monitoring of temperature fluctuations (controlled within ±500K) and flow field stability is necessary, requiring fine-tuning. , Alternatively, the gas ratio can achieve the target effect of spheroidization rate ≥95% and purification rate ≥90%.

[0037] Part Name: Example 1: A temperature control method for processing graphite using a single plasma source This embodiment details the specific application of a temperature control method for single-plasma source processing of graphite. The method is applied to a graphite powder processing device comprising a plasma source 1 and a powder feeding mechanism 3. The core of the implementation process lies in achieving precise and stable control of the plasma processing temperature, avoiding the problem of large temperature fluctuations caused by parameter mismatches in existing technologies.

[0038] First, the initial parameters of the device are set. The operator needs to determine the baseline value of the plasma source gas flow rate m2 based on the target processing temperature. On this basis, strictly following the proportional relationship defined in the claims, the value of the powder feeding mass flow rate m1 is calculated and set, ensuring that the ratio of m1 to m2 is within the specified range. This matching relationship is the core of temperature control; it ensures that the heat absorbed by the fed graphite powder is balanced with the heat provided by the plasma, thereby maintaining the graphite powder processing temperature stably within the optimal range.

[0039] Secondly, to ensure the reliability of temperature control, the powder feeding conditions need to be constrained. The powder feeding mass flow rate m1 must be set in relation to the particle size d of the graphite powder to be processed, satisfying a specific constraint relationship: the value of m1 must not exceed 0.01 times the value of d. This measure prevents temperature instability or insufficient heating caused by feeding too much or too little powder per unit time.

[0040] Finally, during device operation, the power of plasma source 1 needs to be controlled below a certain level to adapt to the continuous powder feeding process. Through the coordinated control of the above flow parameters, this embodiment successfully achieved precise and stable control of the graphite powder processing temperature, and temperature fluctuations were effectively suppressed within a small range, which is significantly better than the prior art, laying a solid foundation for obtaining graphite powder products with high sphericity in the future.

[0041] Example 2: A method for controlling the flow field uniformity in graphite processing using a single plasma source This embodiment details the application of a flow field uniformity control method for graphite processing using a single plasma source. The method is applied to a graphite powder processing device comprising a plasma source 1 and a powder feeding mechanism 3. The key to this implementation is optimizing the spatial position of the powder feeding mechanism 3 to ensure a uniform and stable plasma flow field, thereby solving the problem in existing technologies where graphite powder suffers from uneven heating and poor particle size distribution due to encountering a non-uniform flow field.

[0042] The first step in implementation is to determine the installation position of the powder feeding mechanism 3. The operator needs to accurately measure the outlet diameter D1 of the plasma source 1, and then, according to the claims, calculate and set the axial length L1 of the powder feeding mechanism 3 from the outlet of the plasma source 1. L1 must be greater than or equal to five times D1. This distance ensures that the plasma jet has fully developed before reaching the powder feeding point, the core high-temperature region becomes stable, and flow field velocity fluctuations are limited to a low level.

[0043] Furthermore, the depth of the powder feeding tube of the powder feeding mechanism 3 penetrating into the plasma region is also a critical parameter. This penetration depth needs to be strictly controlled and must not exceed half the diameter of the plasma torch outlet. This design aims to avoid unnecessary disturbance to the already stable plasma flow field caused by the powder feeding tube, ensuring that graphite powder can uniformly enter and pass through the plasma core region.

[0044] By precisely controlling the axial distance L1 and penetration depth of the powder feeding mechanism 3 as described above, this embodiment ensures that the graphite powder enters a processing environment with a uniform flow field and stable temperature. This not only ensures that each graphite powder particle receives a consistent and sufficient heating time, effectively improving the spheroidization rate, but also avoids product quality inconsistencies caused by local overheating or undercooling, achieving precise control of flow field uniformity.

[0045] Example 3: A method for controlling the purification rate of graphite processed by a single plasma source This embodiment details the specific application of a method for controlling the purification rate of graphite processed by a single plasma source. This method is mainly applied to a processing device containing a plasma source 1. Its core lies in selectively improving the purity of graphite powder by choosing a suitable type of plasma gas, thereby meeting the stringent purity requirements of high-end applications.

[0046] During implementation, the choice of gas type is crucial to the purification effect. When the goal is to efficiently remove impurities from graphite powder, especially metal oxides, hydrogen should be the preferred plasma source gas. Hydrogen has strong reducing properties in high-temperature plasma conditions, and can react chemically with impurities to generate volatile products, thereby separating them from the graphite and achieving a high purification rate in the final product.

[0047] Another effective option is to use a mixture of argon and hydrogen, with the hydrogen volume percentage controlled within a specific range. This mixed gas scheme combines the advantages of argon as a commonly used working gas—its stable plasma state and smooth arc combustion—with the chemical reduction and purification capabilities of hydrogen. It is suitable for scenarios requiring both a certain level of spheroidization and efficient purification.

[0048] This embodiment enhances the purification process at the chemical reaction level by optimizing the plasma gas medium. Compared to existing technologies that rely solely on physical heat volatilization to remove impurities, this method is more efficient and effective. It enables a single plasma source processing device to efficiently improve the purity of graphite powder while simultaneously spheroidizing it, meeting the demand for high-purity graphite powder in fields such as semiconductors and high-performance batteries.

[0049] Example 4: A gas-selective temperature and purification synergistic control method This embodiment describes a synergistic method combining temperature control and purification rate control, applied to a processing apparatus comprising a plasma source 1 and a powder feeding mechanism 3. This method, while ensuring precise temperature control, simultaneously optimizes spheroidization and purification effects through specific gas selection, embodying the integrated application of multiple features described in the claims.

[0050] During implementation, the first step is to precisely match the ratio of the powder mass flow rate m1 to the plasma source gas flow rate m2 according to the requirements of the temperature control method, so as to provide a stable and suitable temperature environment for the spheroidization treatment of graphite powder. This is the basic condition for achieving efficient spheroidization.

[0051] In this embodiment, a mixture of argon and hydrogen is specified as the plasma source gas. The volume ratio of hydrogen must be controlled within a specific range. Argon, as the main gas, ensures the stability of the plasma arc and effective heat transfer, providing a good foundation for temperature control. The addition of a specific proportion of hydrogen introduces a chemical purification mechanism. At high temperatures, hydrogen can effectively reduce impurities such as metal oxides carried in the graphite powder, causing them to be discharged in gaseous form, thereby significantly improving the final purity of the product.

[0052] This method achieves synergy between physical heating and chemical reaction. On the one hand, flow control ensures the stability and uniformity of heat treatment, guaranteeing the spheroidization rate. On the other hand, the introduction of active gases endows the process with highly efficient purification capabilities. It successfully combines temperature control and purification rate control methods, simultaneously improving the spheroidization rate and purification rate of graphite powder in a single process, simplifying the process, increasing production efficiency, and making it particularly suitable for applications with high requirements for both.

[0053] Example 5: A graphite powder treatment process with optimized comprehensive parameters This embodiment demonstrates a comprehensive graphite powder processing technology. This method systematically integrates the temperature control, flow field uniformity control, and purification rate control methods described in the previous embodiments. It is applied to a complete device consisting of a power-limited single plasma source 1 and a powder feeding mechanism 3, aiming to achieve stable and efficient preparation of high-quality graphite powder.

[0054] Before starting the process, comprehensive parameter initialization configuration is required. First, based on the outlet diameter D1 of plasma source 1, the axial installation distance L1 of the powder feeding mechanism 3 is strictly determined to meet the requirements of flow field uniformity control and ensure sufficient heating time and a stable processing environment. Second, based on the constraint relationship between the target processing temperature and mass flow rate, the initial values ​​of the powder feeding mass flow rate m1 and the plasma source gas flow rate m2 are calculated and set, laying the foundation for temperature control. Simultaneously, based on the purity requirements of the final product, a suitable plasma gas type is selected, such as an argon-hydrogen mixture to balance stability and purification needs.

[0055] During operation, the various parameters are interrelated and require coordinated monitoring and fine-tuning. The powder flow rate m1 must not only match the gas flow rate m2 but also satisfy its constraint relationship with the graphite powder particle size d. The power of plasma source 1 must be maintained below its rated power to ensure stable operation of the entire system under continuous powder feeding conditions. Through comprehensive optimization and control of all the above parameters, this process embodiment ensures that the graphite powder undergoes sufficient heating time in the plasma core region with a uniform flow field and stable temperature, and may be accompanied by a highly efficient gas-phase purification reaction.

[0056] Ultimately, this integrated process successfully overcame several shortcomings of existing technologies, stably producing graphite powder products with high sphericity and high purity. The entire process parameters are clearly defined, highly controllable, and reproducible, fully demonstrating the advantages of this invention in improving the quality and efficiency of graphite powder plasma treatment.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A temperature control method for processing graphite using a single plasma source, comprising a plasma source (1) and a powder feeding mechanism (3) processing apparatus, characterized in that: Matching the quality flow of the feed ( ) and plasma source gas flow rate ( The ratio of ) is 0.005~0.05 g / s·slm, so that the graphite powder treatment temperature is maintained at 8000~10000K.

2. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: The axial length of the powder feeding mechanism (3) from the plasma source (1) outlet ( ≥5 × plasma source outlet diameter ( ),in The diameter is 10~50mm to ensure that the flow field velocity fluctuation is ≤10%.

3. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: Hydrogen or a mixture of argon and hydrogen is selected as the plasma source gas to achieve a graphite powder purification rate of ≥90%.

4. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: The temperature (T) of plasma (2) and the flow rate of plasma source gas ( The following relationship is satisfied: T = 4500 + 75 × (K).

5. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: Powder delivery mass flow rate ( The relationship between the particle size (d) and the graphite powder particle size is as follows: ≤0.01×d (g / s).

6. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: The power range of the plasma source (1) is controlled below 50kW to adapt to the continuous conveying conditions of the powder mass flow rate of 0-1g / s.

7. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: The heating time of the graphite powder in the plasma core region is set to ≥0.1 seconds to ensure that the graphite powder is fully spheroidized.

8. The temperature control method for single plasma source processing of graphite according to claim 2, characterized in that: The depth of the powder feeding tube of the powder feeding mechanism (3) penetrating the plasma region ( The diameter of the plasma torch outlet should not exceed 1 / 2 to avoid flow field disturbance.

9. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: The plasma gas is a mixture of argon and hydrogen, with hydrogen accounting for 5%-15% of the volume, used to simultaneously improve the spheroidization rate and purification effect.

10. The temperature control method for single plasma source processing of graphite according to claim 1, characterized in that: The graphite powder has a particle size range of 0-100 μm, and the powder feeding mass flow rate is... The relationship between the particle size d and the particle size d is satisfied Constraints ≤0.01d (g / s).

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