Processing system and method for manufacturing spheroidized graphite powder using single variable RPM mill

Abstract

The present disclosure relates to a system (100) for manufacturing spheroidized graphite powder, the system comprising a feeder (104) adapted to convey primarily pulverized particles to a grinding section (106). A first classifier (108) is located at the top of the chamber and is configured to receive the milled particles and is adapted to separate the milled particles into first particles and second particles. A controller (112) is operably coupled to the one or more motors (110), the controller configured to operate the one or more motors at a progressively varying RPM, at a higher RPM, which cuts rough edges of the particles to form first fine graphite particles and second shaped graphite particles, and when its RPM decreases to a lower level, the first fine graphite particles and the second shaped graphite particles are separated from each other. A surface smoothing process of the shaped particles takes place, which results in surface-smoothed spherical graphite.

Description

Technical Field

[0001] The present disclosure relates generally to graphite spheroidization, and more particularly to a processing system and method for producing spheroidized graphite powder utilizing a single variable RPM mill. Background Art

[0002] Graphite particles have found widespread application as anode materials for lithium-ion secondary batteries and in bipolar plates for fuel cells, etc. Natural graphite flake materials are typically flat in shape, sharp at the edges, and have low tap density, which makes the preparation of anodes for lithium-ion batteries difficult. In addition, it results in lower electrode density, which leads to lower battery energy density and poor life cycle.

[0003] Furthermore, during electrode preparation, natural graphite flakes tend to orient themselves parallel to the current collector. This orientation slows down the intercalation and deintercalation process in lithium-ion batteries, because lithium ions cannot enter the graphite crystals through their "basal plane surfaces" facing the electrolyte, but must bypass the flakes and migrate to the "prismatic surfaces."

[0004] Therefore, a process for making spherical graphite from graphite flakes and coke materials is highly desirable. The process can produce spherical graphite particles with high tap density, smooth surface, and higher compactness, leading to high electrode density, low cost, and high lithium insertion capacity.

[0005] In conventional processes, according to patents CN101391105A and CN110872118A, multiple steps are required to manufacture spherical graphite, which makes the process very expensive and time-consuming. The system is configured to feed flake graphite that has been ground in a primary pulverizer to the required size D50=10-30 microns, and then feed it to 2 to 5 secondary pulverizers in sequence, and then feed it to 10 to 12 forming pulverizers in series, and collect spherical graphite products at the end of the forming pulverizer.

[0006] Therefore, conventional processes require multiple systems, about 20 systems to make spherical graphite. Each system consists of a feeder, mill, primary classifier, secondary classifier, bag filter, blower and control system. This multi-system makes the control and operation of these processes very difficult.

[0007] Another example is described in patent US 6,939,526 B2, which relates to particles of soft flakes folded like spherical onion layers and made into spherical graphite. However, due to its soft nature, when the electrode is calendered to a higher electrode density, the particles tend to break and flatten, resulting in the closure of the surface porosity, thereby resulting in low rate charge and discharge performance.

[0008] Another embodiment is described in patent CN112110444A. The system includes three grinding sections in a single chamber with three drives. The ground / shaped particles with fine powder come out of the grinding chamber and are classified, and then the large particles are directed to the grinding chamber, and the fine powder is collected at the bottom of the cyclone separator. The drive / motor can choose to change the revolutions per minute (RPM) of the motor. However, the process is carried out at a desired fixed RPM. The system also requires multiple drives in the grinding chamber.

[0009] Another method disclosed in US2013 / 0130117A1 describes making spherical graphite in one machine, and then feeding the intermediate particles to another mechanical grinder again to smooth the particle surface. Although it reduces the number of steps, it still requires multiple steps and multiple machines.

[0010] Therefore, it is desirable to overcome the shortcomings, deficiencies and limitations associated with existing solutions and develop a process for making spherical graphite that can eliminate the multiple steps for spheroidization and smoothing of graphite materials used in conventional processes.

[0011] Purpose of this Disclosure

[0012] The objects of the present disclosure relate generally to graphite spheroidization and more particularly to a processing system and method utilizing a single grinding chamber and a single grinding drive that continuously / gradually changes the RPM of the mill for producing spheroidized graphite powder.

[0013] Another object of the present disclosure is to provide a system which enables both the shaping process and the surface smoothing of particles in the same grinding chamber by continuously / gradually varying the RPM of the mill drive.

[0014] Another object of the present invention is to provide a system for producing spherical graphite particles that do not break and flatten during an electrode manufacturing process, thereby having high rate capabilities of the electrode.

[0015] Another object of the present disclosure is to provide a system that is easy to operate and control.

[0016] Yet another object of the present disclosure is to provide a small number of motors, mills, and classifiers, thereby forming a cost-effective system. Summary of the invention

[0017] The present disclosure relates generally to graphite spheroidization, and more particularly to a processing system and method utilizing a single grinding chamber that continuously / gradually varies the RPM of the mill for producing spheroidized graphite powder. The primary object of the present disclosure is to overcome the drawbacks, limitations and deficiencies of existing systems and solutions by providing a system and method utilizing a single continuously / gradually variable RPM mill for producing spheroidized graphite powder.

[0018] The present disclosure relates to a feeder suitable for conveying primary crushed particles to a grinding / forming section enclosed in a chamber. The particles are selected from natural graphite, petroleum and coal tar based coke powders and any combination thereof. These modified natural graphite / coke particles are obtained by a manufacturing method comprising the steps of applying an impact force to the natural graphite / coke particles to cut random edges and spheroidize at high RPM, and smoothing the surface of the particles as the RPM is continuously / gradually reduced.

[0019] The first classifier is located at the top of the chamber. The first classifier is configured to receive the milled / shaped particles and is suitable for separating the powder into first particles and second particles. The first particles are fine graphite particles and the second particles are spherical graphite particles. One motor is connected to the grinding section and the other motor is connected to the first classifier. The grinding and classifier motors can be operated independently to rotate gradually / continuously at a variable RPM from high to low or from low to high. The change in RPM of the grinding motor is described, where x = milling RPM-y, y is between 0 and 200 RPM. The RPM change of classifier-1 is shown, where m = RPM-n of 70% of the maximum RPM of the classifier, where n is between 0 and 50 RPM.

[0020] The controller is operably coupled to the one or more motors, the controller being configured to operate the one or more motors at a high RPM to cut the rough edges of the particles at a higher RPM to form the first and second particles. The controller is configured to operate the classifier at a lower RPM to facilitate the removal of the first fine graphite particles through the first classifier, and further directing the second particles to the grinding chamber, wherein at the low RPM of the grinding mill, the surface of the formed particles is smoothed to form spherical graphite, thereby facilitating the smoothing and shaping process in a single grinding system.

[0021] Further, the spheroidization process is carried out in a single mill by applying impact and shear forces, wherein the forces are generated by rotating hammers and fixed liners in the mill using variable RPM of the rotor, thereby grinding the graphite in a short time. Smooth spherical graphite with low surface area is obtained by rotating the rotor of one or more motors using variable RPM from high to low RPM.

[0022] In addition, spherical graphite is coated with a carbon source, such as pitch, followed by carbonization / graphitization to produce a spherical graphite anode powder, wherein the purified spherical graphite has a carbon content of less than 2 μm. 2 / g surface area and a high tap density of 1.2g / cc, providing 368mAh / g and a first cycle coulombic efficiency of 94%. The spherical graphite prepared by the claimed process shows an orientation index of less than 50. The orientation index is determined by powder x-ray diffraction analysis. 002 / I 110 For batteries with high rate and long cycle life, the lower the index, the better.

[0023] The surface area of ​​the prepared spherical graphite particles is less than 8m2 / g at a diameter D50 of 10 μm, and less than 6m2 / g at a diameter D50 of 15 μm, with a smooth surface. The obtained spherical graphite particles have an aspect ratio (L / D) in the optimum range of 1.2, a forming rate of more than 65%, and a tap density of 0.99 for a diameter D50 of 10 μm.

[0024] It will be appreciated by those skilled in the art that the present invention avoids a large number of motors, mills and classifiers, and does not require the use of additional particles and additional assembly operations, thereby reducing the cost of the system. In addition, the system can use only about ten motors for grinding and spheroidization, which is easy to operate and control.

[0025] Various objects, features, aspects and advantages of the present subject matter will become more apparent from the following detailed description of preferred embodiments and the accompanying drawings, wherein like numerals represent like parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following drawings constitute part of this specification and are included to further illustrate various aspects of the present disclosure. The present disclosure may be better understood by reference to the drawings in conjunction with the detailed description of specific embodiments presented herein.

[0027] Figure 1A An exemplary single mill grinding and first classifier according to an embodiment of the present disclosure is illustrated.

[0028] Figure 1B An exemplary spherical forming process system according to an embodiment of the present disclosure is illustrated.

[0029] Figure 1C An exemplary block diagram of a single processing system according to an embodiment of the present disclosure is illustrated.

[0030] Figure 2A An exemplary block diagram for RPM variation of a grinding motor according to an embodiment of the present disclosure is illustrated.

[0031] Figure 2B An exemplary block diagram of RPM variation for a first classifier motor according to an embodiment of the present disclosure is illustrated.

[0032] Figures 3A to 3D An exemplary scanning electron microscope (SEM) view of spheroidized graphite according to an embodiment of the present disclosure is illustrated.

[0033] Figure 4 An exemplary method for producing spheroidized graphite powder according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0034] The following is a detailed description of the embodiments of the present disclosure depicted in the accompanying drawings. The embodiments are described in such detail to clearly convey the present disclosure. If the specification states that a component or feature "may," "could," "can," or "might" be included or have a property, the specific component or feature need not be included or have the property.

[0035] As used in the description herein and throughout the claims that follow, the meanings of "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Additionally, as used in the description herein, the meaning of "in" includes "in" and "on," unless the context clearly dictates otherwise.

[0036] The present disclosure relates generally to graphite spheroidization, and more particularly to a processing system and method utilizing a single system for making spheroidized graphite powder utilizing continuous / gradual changes in the RPM of a pulverizer.

[0037] The term "spheroidization" herein refers to shaping graphite flake particles into spherical or nearly spherical graphite particles.

[0038] The proposed system disclosed in the present disclosure overcomes the disadvantages, deficiencies and limitations associated with conventional systems by providing a system comprising a feeder adapted to deliver primary pulverized particles to a grinding section enclosed in a chamber. The particles are selected from natural graphite flakes, petroleum and coal tar based coke powders and any combination thereof. The term "flake" describes crystalline graphite composed of highly ordered layers which ultimately define the size ratios of the particles.

[0039] Further, a first classifier is located at the top of the grinding chamber, the first classifier is configured to receive the milled particles and is suitable for separating the milled particles into first particles and second particles. The controller is configured to operate one or more motors to continuously / gradually change the RPM to cut the rough edges of the particles to form fine graphite particles, and gradually reduce at a low RPM to smooth the surface of the particles to form spherical graphite created at the end of the process. The fine graphite particles are transferred from the top outlet of the chamber to the first housing, and the spherical graphite is transferred from the middle outlet of the chamber to the second classifier after being formed for a preset time.

[0040] The controller is configured to perform the spheroidizing process by applying impact force and shear force, the force being generated by the rotating hammers and the fixed bushing of the grinding section using the variable frequency of the rotor. The obtained spherical graphite particles have a length-to-diameter (L / D) ratio within an optimal range of less than 1.2, with a forming rate of more than 65%.

[0041] In addition, the spherical graphite is coated with a carbon source, such as pitch, followed by carbonization / graphitization at a temperature in the range of 2600° C. to 2900° C. to produce a graphite anode powder, wherein the purified spherical graphite has a carbon content of less than 2 μm. 2 / g surface area and a tap density material of 1.2 g / cc for a 10 micron powder.

[0042] The treated graphite anode powder provides more than 365 mAh / g as discharge capacity, and more than 93% first cycle efficiency. The present disclosure may be described in detail in the following examples, which may represent more than one embodiment of the present disclosure.

[0043] The advantages achieved by the system of the present disclosure can be clearly seen from the embodiments provided herein. The system enables surface area shaping and smoothing processes of particles. The system avoids the breakage and flattening of particles during electrode calendering, thereby achieving high rate performance. The present disclosure provides a small number of motors, mills and classifiers, resulting in a cost-effective system and easy to operate and control. The descriptions of terms and features related to the present disclosure should be clear from the embodiments illustrated and described; however, the present invention is not limited to these embodiments. Within the scope of the present disclosure, various modifications, changes, variations, substitutions and equivalents may be made to the embodiments. In addition, the present invention may include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.

[0044] Figure 1A An exemplary single mill grinding and first classifier according to an embodiment of the present disclosure is illustrated.

[0045] refer to Figure 1A, a single mill processing system 100 (also referred to herein as system 100) is configured to perform spheroidization of graphite. System 100 may include a feeder 104, a grinding section 106 enclosed in a chamber 102, a first classifier 108, a programmable logic controller (PLC) 112, and a motor 110. The particles shown in the embodiment may be natural flake graphite or coke particles.

[0046] In one embodiment, the particles are conveyed to the grinding section 106 by the feeder 104, where deformed particles are obtained. The particles are primary crushed to about 20 microns in the primary crusher and fed to the grinding section 106 in the chamber 102. The grinding section 106 is connected to the first classifier 108 located at the top of the chamber 102. The chamber 102 may include a top outlet 114 and a middle outlet 116. The top outlet 114 of the chamber 102 is connected to the first housing 118, and the middle outlet 116 is connected to the second classifier 120. The first housing 118 is connected to the second housing 122, wherein the second housing 122 may include a bag filter 126, and finally, the second housing 122 is connected to the blower 128.

[0047] In one embodiment, one or more motors 110 are coupled to the grinding section 106 and the first classifier 108. The one or more motors 110 are operated to rotate at a gradually variable frequency from high to low or from low to high RPM. A programmable logic controller (PLC) (also referred to herein as controller 112) is operably coupled to the one or more motors 110 and valves (124, 130). The PLC 112 is configured to operate the one or more motors 110 at a variable RPM. The controller 112 is configured to operate the one or more motors 110 at a high RPM with a gradually changing RPM to cut off the rough edges of the particles, and then gradually reduce to a low RPM to smooth the surface of the graphite. The controller 112 is configured as follows, respectively Figure 2A and Figure 2B As shown, by applying the impact force and shear force generated by the rotating hammer and the fixed bushing in the system 100 using the variable frequency of the rotor, Figure 1A and Figure 1B The spheronization process is performed separately in the individual mills shown, thereby facilitating the grinding of particles in a short time. The hammers are made of hardened steel and carbide tipped hammers. The bushings are made of hardened steel material and their height is 4 times the height of the hammers.

[0048] The first classifier 108 is configured to receive the milled particles and is suitable for separating the milled particles (e.g., graphite) into first particles and second particles. The first particles may be fine graphite particles, and the second particles may be spherical graphite. Further, the first classifier 108 may only allow the fine graphite particles to be distributed from the top outlet 114 of the chamber 102, and after forming for a preset time, the formed particles, i.e., spherical graphite, are collected at the middle outlet 116 of the chamber 102.

[0049] For example, the particles are fed into the chamber for 15 minutes. Initially, when the motor 110 maintains a high RPM, the edges of the flakes are cut and begin to bend. The irregular edges of the particles are cut to form fine graphite particles and the motor 110 is gradually reduced to a frequency of low RPM, and the edges are folded to smooth the surface to form spherical graphite particles. The fine particles are allowed to pass through the top outlet 114 of the chamber 102. After the preset time, the valve is opened, and the formed particles, such as spherical graphite, pass through the middle outlet 116 and are collected at the bottom of the second classifier 120.

[0050] The fine particles are transferred to the valve 130 located in the first housing 118, and are further processed using a bag filter 126 provided in the second housing 122, and are sent to the blower 128 to obtain fine graphite particles. The spherical graphite is transferred to the second classifier 120 and collected at the bottom of the second classifier 120 through the discharge valve 124.

[0051] Figure 1C An exemplary block diagram of a single processing system according to an embodiment of the present disclosure is illustrated. Particles are conveyed to a grinding section 106 by a feeder 104. The grinding section 106 is coupled to a first classifier 108, which is configured to receive the milled particles and is adapted to separate the milled particles into first particles and second particles. A controller 112 is operably coupled to one or more motors 110 at a high RPM to cut rough edges of the particles to form first particles belonging to fine graphite particles, and operates at a low RPM to smooth the surface of the particles to form second particles belonging to spherical graphite.

[0052] The spherical natural graphite obtained by this process can be coated with a carbon source, such as pitch, and treated at a temperature of about 2600°C to 2900°C while undergoing a carbon coating and purification process. The spherical graphite is coated with pitch, followed by carbonization / graphitization, to produce a graphite having a carbon content of less than 2 m 2 / g surface area and 1.15g / cc tap density material. First, the pitch-coated graphite was heat treated at 500°C for about 30 minutes and then carbonized at 1,000°C for about one hour. Subsequently, graphitization was performed at a temperature of about 2,900°C.

[0053] In this embodiment, the coating is essentially a partially graphitized carbon shell that protects the spherical graphite particles from peeling and improves the cycle stability by inhibiting the reaction between the electrolyte and the graphite particles, resulting in increased battery capacity and life. Further, the carbon coating (such as a pitch-derived amorphous carbon coating) effectively reduces the irreversible capacity. The coating of carbon pitch can also be performed by solvent or other coating techniques.

[0054] The spherical graphite particles are purified to remove harmful elements including silicon dioxide (SiO2), iron (Fe) and other metallic elements. The purification is performed by some purification techniques, such as aggressive acid purification using hydrofluoric acid and thermal purification, or other similar techniques. The spherical graphite particles obtained after thermal purification have a particle size of less than 2 μm. 2 / g surface area and 1.2 g / cc tap density, which shows the very spherical nature of the particles.

[0055] Purified natural graphite has a particle size of less than 2 m 2 / g surface area and a high tap density of 1.2 g / cc, which gives 368 mAh / g and a first cycle coulombic efficiency of 94%. As analyzed by the powder X-ray diffraction method, the powder orientation index of the spherical graphite is less than 70.

[0056] The surface area of ​​the uncoated spherical graphite particles at a diameter D50 of 10 μm is less than 8 m2 / g, and the surface area at a diameter D50 of 15 μm is less than 6 m2 / g, with a smooth surface. The obtained spherical graphite particles have an aspect ratio (L / D) in the optimal range of 1.2, a forming rate of more than 65%, and a tap density of 0.99 for a diameter D50 of 10 μm. The lower L / D ratio, the higher tap density and the lower surface area indicate that the spherical properties are good and the surface is smooth.

[0057] refer to Figure 2A and Figure 2B , Figure 2A The variation of the grinding motor RPM is shown, where x = grinding RPM and y is between 0 and 200 RPM. Figure 2B The variation of RPM for the first classifier is shown, where m = RPM at 70% of the maximum RPM of the classifier - n, with n ranging from 0 to 50 RPM.

[0058] Thus, the present invention overcomes the disadvantages, deficiencies and limitations associated with prior solutions and provides a cost-effective system that reduces defects, resulting in a shaped graphite with a smaller surface area. The generation of fine powder is also reduced, thereby increasing the yield. This is achieved by continuously changing the RPM from high to low at a predetermined reduction rate. At the higher end of the frequency, the irregular edges of the particles are cut, and at the lower end of the frequency, the edges are folded and the surface becomes smooth. Further, the system can use only about ten motors for grinding and spheroidizing, which is easy to operate and control, thereby reducing capital costs.

[0059] Experimental Results

[0060] Figures 3A to 3D An exemplary scanning electron microscope (SEM) view of spheroidized graphite according to an embodiment of the present disclosure is illustrated. Figure 3A and Figure 3B As depicted in , considering the diameter size D50 of the graphite particles, when the controller operates the motor at 2800 RPM (Comparative Example 1) or 2400 RPM (Comparative Example 2), the correct shape of the particles is not obtained. Therefore, in order to obtain graphite particles with a D50 of 10 microns (Example 1), the controller operates the grinding motor from 2800 RPM to 2400 RPM gradually, as shown in FIG. Figure 2A As shown. Where x = 2800RPM, y = 100RPM and T1 to T5 = 3min. The classifier motor is Figure 2B The control was performed with m=2600RPM, n=50RPM and T1 to T5=3min. The gradual control of RPM can produce good spherical particles with smooth surface, such as Figure 3C shown.

[0061] Similarly, to obtain spherical graphite particles with a D50 of 15 microns, the RPM is adjusted as follows; the grinding motor is gradually reduced from 1300 RPM to 1900 RPM, such as Figure 2A As shown. Where x = 1300RPM, y = 100RPM and T1 to T5 = 3min. The classifier motor is Figure 2B Control was performed where m = 2600 RPM, n = 50 RPM and T1 to T5 = 3 min. This process (Example 2) gave 15 micron spherical graphite powder with a tap density greater than 1.02 g / cc and a surface area less than 6 m2 / g.

[0062] The proposed system 100 can be operated to produce particles of different sizes by optimizing the process parameters. It can give 10 micron particles and 15 micron particles by the same process using different parameters, as shown in Example 1 and Example 2. The experimental data for producing spheroidized graphite from a single processing system is described in Table 1 below.

[0063]

[0064] Table 1: Experimental data for producing spheroidized graphite from a single processing system.

[0065] However, these are merely exemplary values, actual values ​​may range widely, and the values ​​included here are for illustration purposes only, as other values ​​and integer multiples are possible.

[0066] Figure 4 An exemplary method for producing spheroidized graphite powder according to an embodiment of the present disclosure is illustrated.

[0067] refer to Figure 4 , a method 400 for manufacturing spheroidized graphite powder. At block 402, a feeder can deliver primary crushed particles to a grinding section enclosed in a chamber. In block 404, a first classifier can receive the milled particles and is suitable for separating the milled particles into first particles and second particles, the first classifier being located at the top of the chamber.

[0068] At block 406, the controller can be operatively coupled to the first classifier and can operate the one or more motors at a gradually varying RPM, operating at a high RPM to cut the rough edges of the particles to form the first particles and operating at a low RPM to smooth the surface of the particles to form the second particles. One or more motors are coupled to the grinding section and the first classifier, the one or more motors being adapted to rotate at a variable frequency from high to low or from low to high RPM.

[0069] It will be apparent to those skilled in the art that some or all of the features and components mentioned may be used to provide the system 100 of the present disclosure without departing from the scope of the present disclosure. Although various embodiments of the present disclosure have been illustrated and described herein, it is apparent that the present disclosure is not limited to these embodiments. It will be apparent to those skilled in the art that various modifications, changes, variations, substitutions and equivalents will occur without departing from the spirit and scope of the present disclosure as described in the claims.

[0070] Advantages of the present invention

[0071] The present invention provides a system capable of achieving particle shaping and surface smoothing.

[0072] The present invention provides a system to avoid particle breakage and flattening during calendering, thereby maintaining uniform porosity in the electrode, which will contribute to high rate performance and long cycling.

[0073] The present invention provides a system that is easy to operate and control.

[0074] The present invention provides a small number of motors, mills and classifiers, thereby forming a cost-effective system.

Claims

1. A system (100) for producing spheroidized graphite powder, the system comprising: a feeder (104) adapted to deliver primary comminuted particles to a grinding section (106) enclosed in the chamber (102); a first classifier (108) located at a top of the chamber, the first classifier (108) being configured to receive the milled particles and adapted to separate the milled particles into first particles and second particles; one or more motors (110) coupled to the grinding section (106) and the first classifier (108), the one or more motors (110) being operated to rotate at a gradually variable frequency of revolutions per minute (RPM) from high to low or from low to high; and a controller (112) operably coupled to the one or more motors, the controller being configured to: operating the one or more motors at a high RPM with a gradually changing RPM to cut rough edges of particles to form the first particles as fine graphite particles; and The one or more motors are operated at a low RPM with a gradually changing RPM to smooth the surface of the particles to form the second particles which are spherical graphite particles.

2. The system of claim 1, wherein the particles are selected from the group consisting of natural graphite, artificial graphite, petroleum coke powder, and any combination thereof.

3. The system according to claim 1, wherein the fine graphite particles are transferred from a top outlet (114) of the chamber (102) to a first housing (118), and the spherical graphite particles are transferred from a middle outlet (116) of the chamber (102) to a second classifier (120) after being formed for a preset time.

4. The system of claim 1, wherein the spherical graphite particles are coated with carbon pitch followed by carbonization to produce spherical graphite powder, wherein the purified spherical graphite particles have a particle size of less than 2 μm. 2 / g surface area and 1.2g / cc tap density material.

5. The system of claim 1, wherein the powder orientation index of the spherical graphite particles is less than 40.

6. The system of claim 1, wherein the smooth spherical graphite particles having a low surface area are obtained by rotating a rotor of one or more motors (110) with a gradually varying RPM.

7. The system of claim 1, wherein the spherical graphite particles obtained have a length to diameter (L / D) ratio in the optimal range of 1.2, a forming rate exceeding 65%, and a tap density of 0.99 g / cc for a diameter D50 of 10 micrometers (μm).

8. The system of claim 1, wherein the surface area of ​​the spherical graphite particles is less than 8 m at a diameter D50 of 10 μm. 2 / g, at a diameter D50 of 15 μm, the surface area of ​​the spherical graphite particles is less than 6 m 2 / g, with a smooth surface.

9. The system of claim 1, wherein the controller (112) is configured to perform a spheroidizing process by applying impact force and shear force, the force being generated by a rotating hammer and a fixed bushing of the grinding section using a variable frequency of a rotor, wherein the spherical graphite particles are formed.

10. A method (400) for producing spheroidized graphite powder, the method comprising: conveying (402) the primary crushed particles to a grinding section enclosed in a chamber via a feeder; receiving (404) the milled particles at a first classifier and adapted to separate the milled particles into first particles and second particles, the first classifier being located at a top portion of the chamber; and One or more motors are operated (406) by a controller at a high RPM with a gradually varying RPM to cut rough edges of particles to form the first particles which are fine graphite particles, and the one or more motors are operated at a low RPM with a gradually varying RPM to smooth the surfaces of the particles to form the second particles which are spherical graphite, wherein the controller is operably connected to the one or more motors, and the one or more motors are connected to the grinding section and the first classifier.

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