Method for increasing yield of rounded graphite particles

Abstract

To provide a method for producing spheroidal particles from graphite materials that is easy to control and can leave behind less fine material to be discarded and can provide a higher yield of useful material.SOLUTION: The present invention relates to a method for producing graphite particles of certain, different fineness classes rounded by impact effect, with the help of plural spheroidal separators, which are connected in series, wherein the graphite material to be rounded is pre-comminuted, and a first spheroidal separator then produces graphite material of a first fineness class, which is spheroidized by means of folding, from the graphite material and discharges the resulting graphite material of the first fineness class as end product, and simultaneously separates graphite material, which can predominantly not be processed to graphite material of this first fineness class because it is too comminuted, and feeds the separated graphite material, which is too comminuted, to a second spheroidal separator, and the second spheroidal separator produces graphite material of a second, finer fineness class, which is spheroidized by means of folding, from the separated graphite material and discharges the resulting graphite material of the second fineness class as end product.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for rounding graphite particles, also referred to as spheronization, that can increase the yield of rounded graphite particles while reducing waste. [Background technology]

[0002] Lithium-ion batteries are currently the power source of choice for powering electrical devices ranging from laptops and hand tools to automobiles.

[0003] It is conventional to equip lithium-ion batteries with anodes made of graphite. On the one hand, the graphite anode has the role of conducting and supplying electric current to the outside, for which purpose graphite is essentially optimal. Furthermore, lithium ions must flow to the graphite anode and be stored in the grid structure of the anode whenever electric current flows from the battery cell through the electrolyte.

[0004] In addition to chemical purity, the morphology of the graphite also plays an important role.

[0005] Spherical graphite (SPG) is ideal as an anode material. Its smooth, significantly less anisotropic, and therefore universally receptive surface can effectively interact with the Li-ions stored in the anode material, providing a large anode chargeability. Furthermore, spherical graphite has a smaller tendency to exfoliate and the associated irreversible capacity loss, allowing a longer service life to be achieved. Overall, therefore, higher energy densities and longer service lives can be achieved with spherical graphite.

[0006] In nature, graphite exists as so-called flake graphite distributed in rocks, for example, as shown in FIG.

[0007] Untreated flake graphite, having a layered morphology, exhibits pronounced basal planes. These are planes that run parallel to the crystal structure of graphite. Along these planes, graphite is an extremely good thermal as well as electrical conductor, whereas transverse to the basal planes, i.e., between the individual planes, it can be considered a thermal and electrical insulator. Thus, flake graphite exhibits pronounced anisotropy.

[0008] For this reason, flake graphite must be processed from which the required spherical graphite is produced, since the basal surface problem is practically irrelevant in spherical graphite. Spherical graphite is therefore much more suitable for electrical applications. Figure 2 shows the appearance of spherical graphite material of fine (fineness) class SPG20.

[0009] Other fine classes that are often required in practice include fine classes SPG 22, 18 and 10. As known to those skilled in the art, fine class SPG 20 refers to, for example, 50 is 20 μm, i.e. 50% of the particles making up the graphite material have an equivalent diameter smaller than 20 μm. Similarly, the same applies to the other fine classes.

[0010] The corresponding process is known in the art, although it is still a fairly new technique: this technique is called spheronization.

[0011] Spheroidization is not achieved, for example, by crushing or cylindrical grinding of individual particles of flake graphite, but by the so-called folding of the graphite flakes multiple times by repeatedly colliding the graphite flakes, carried by a carrier or process gas stream, with obstacles with kinetic energies selected such that the graphite particles are not crushed but are folded and thus deformed.

[0012] A cascade of about 20-30 separator mills connected in series, to which an externally generated process gas stream is applied, is a common continuous process for the spheroidization of graphite. Between every two successive separator mills in the cascade, additional separators, filters and fans are provided. During continuous operation, these separator mills operate as follows:

[0013] The first separator mill in the cascade is continuously fed with unprocessed "raw graphite" and graphite rounded to the desired particle size, in other words useful material, i.e. the desired fine class of graphite material, can only be extracted from the last separator mill in the cascade.

[0014] The desired roundness and fineness class is approached incrementally with each individual separator mill.

[0015] When the raw graphite is rounded significantly below a specific size in the first separator mill, it is inevitably discharged from the separator mill together with the fine material that inevitably occurs during rounding. The graphite then undergoes further separation and filtration to separate fine material (i.e. particles that are already too small for the purpose) and graphite material that can be subjected to the next rounding step and can be reused. The fine material is discarded. The remaining graphite material is then fed to the next separator mill in the cascade, which also subjects the remaining graphite material to the next rounding step and discharges it again once the smaller specific size is reached.

[0016] This method is difficult to control in practice due to the large cascade misalignment involving different system components. The discarded fine material accumulates as a no longer usable mixture with various particle sizes.

[0017] Recently, Augsburg-based Hosokawa Alpine AG published an improved spheronization method in the trade journal Carbon 201 (2023) 847-855.

[0018] For more efficient spheronization, the following batch method is proposed.

[0019] In this case, the raw graphite is first subjected to the actual grinding process in a separator mill, which pre-grinds the raw graphite to produce graphite flakes that are small enough to produce the desired quality or fine class of spheroidal graphite in a single subsequent spheroidization step. This pre-grinded graphite material is then introduced in small quantities into the particular separator mill.

[0020] The separator mill is provided with a device for folding and spheroidizing the graphite particles multiple times instead of grinding them unnecessarily. The separator mill generates strong turbulences internally during operation and is therefore said to function without an externally generated process gas flow. After a certain processing time, the desired degree of spheroidization is reached. The contents are then removed from the particular separator mill. The graphite mixture thus obtained is sent to a separator, which separates the finished spherical graphite particles from the accompanying fine material to be discarded.

[0021] This method is well controllable and has a high throughput. A drawback of this method is that a significant amount of the raw graphite used accumulates as fine material and is discarded because it is too fragmented for further use. [Prior art documents] [Non-patent literature]

[0022] [Non-Patent Document 1] Carbon 201 (2023) 847 - 855. Hosokawa Alpine, Augsburg Summary of the Invention [Problem to be solved by the invention]

[0023] The object of the present invention is to propose a spheroidizing method which is easy to control and which at the same time makes it possible to make better use of the graphite material used, i.e. less fine material to be discarded and a higher yield of useful material. [Means for solving the problem]

[0024] According to the invention, this problem is solved by a spheronization method as claimed in claim 1.

[0025] The process of the present invention uses uniformly pre-ground raw graphite to produce specific different fine classes of graphite particles which are rounded by impact effect.

[0026] In this case, multiple spheroidizing separators connected in series are used.

[0027] The method according to the invention starts with a preliminary grinding of the graphite material to be rounded, suitable for producing the coarsest fineness class of the different fineness classes produced by the method according to the invention.

[0028] The first spheroidizing separator is then filled with the pre-ground raw graphite, which produces, by folding, a spheroidized first fine class graphite material from the graphite, which after a batch time is discharged from the first spheroidizing separator as a useful material, i.e. as a final product, and therefore does not pass through further spheroidizing separators.

[0029] During the batch, the first spheronizing separator separates fine material that cannot be substantially processed into this first fine class that the first spheronizing separator is responsible for producing through its separator wheel, because the particles of this fine material are too small. This graphite material that constitutes the fine material may partly already originate from the pre-grinding, but may also partly consist of breakages that have undesirably occurred during rounding in the first spheronizing separator.

[0030] The graphite material separated as fine material is fed to a second spheroidizing separator which can and does produce a second finer class of spheroidized graphite material from the separated graphite material by folding. Preferably, the second finer class of graphite material is also centrifuged directly from the second spheroidizing separator after a batch time as useful material, i.e. as the final product. Thereafter, the graphite material does not pass through any further spheroidizing separators.

[0031] Thus, the basic solution concept of the method according to the invention is to use a raw graphite that is appropriately pre-ground only for the coarsest fineness class in order to produce spheroidized graphite of different fineness classes. In order to produce a material suitable for at least one finer fineness class, the fact is utilized that the spheroidization of graphite in the coarser fineness class is accompanied by a certain further grinding, which causes breakages, which are too small to be suitable for producing the coarser fineness class of graphite, but are quite suitable for processing the finer fineness class of graphite.

[0032] This is also due to the fact that a non-negligible proportion of the broken pieces constituting the fine material is already rounded in the first spheronizing separator, the rounding then being abruptly terminated by the breakage.

[0033] In light of these considerations, it becomes clear that the conventional approach, i.e. very intensive pre-grinding of raw graphite so that a fine class of graphite, e.g. SPG10, can be produced as a useful material by rounding, instead of first seeing to what extent a coarser fine class can be produced, is futile.

[0034] It has been found to be particularly advantageous when determining the intensity at which the pre-grinding or pre-compression is carried out not only to take into account the first spheroidizing separator which provides the coarsest quality level of graphite material, but instead the intensity at which the pre-grinding or pre-compression is carried out is sensible to set in such a way that more than 50% by weight of the graphite material placed in the first spheroidizing separator is separable through the first spheroidizing separator wheel and then placed in a second separator which produces a finer class of graphite material.

[0035] In another particularly advantageous design option, the paddle surface of at least one spheronization separator is enlarged in such a way that the quotient of the net volume of the separator chamber and the paddle surface is in the range of 0.5 to 2.0. In some cases, a tolerance of + / - 10% is allowed, but it is preferred that the stated limits are fully or at least substantially observed.

[0036] In this case, the total volume of the separator chamber minus the envelope volume of the separator wheel is understood to be the net volume of the separator chamber.

[0037] The surface which forms the circumferential edge and against which the graphite particles collide and fold is understood to be the paddle surface.

[0038] This allows the spheroidization process to be accelerated, since more energy can be applied to the material to be spheroidized without increasing the velocity, thus increasing the impact strength and, as a result, increasing the fraction of fine material generated.

[0039] Another design option is to reduce the diameter of the separator wheel to such an extent that the quotient of the net volume of the separator chamber and the envelope volume in the separator wheel (as defined above) is between 4.2 and 6.5. In some cases, a tolerance of + / - 10% is allowed, but it is preferred that the stated limits are fully or at least substantially adhered to.

[0040] This increases the space in which the material to be spheronized rotates, which allows a larger load capacity and at the same time increases the mobility of the material to be spheronized in the separator space, which has a positive effect on the folding process and its yield. [Brief description of the drawings]

[0041] [Figure 1] FIG. 1 is an illustration showing raw graphite present as flake graphite. [Diagram 2] FIG. 1 is an illustration showing spheroidized graphite of fine class SPG22. [Diagram 3] FIG. 2 is a detailed view showing important parts of a spheroidizing separator preferably used in connection with the present invention. [Figure 4] FIG. 2 is an explanatory diagram showing a comparative example corresponding to the Applicant's prior concept for a method not according to the invention, in order to enable a yield comparison with the method according to the invention. [Diagram 5] FIG. 1 is an explanatory diagram showing a first exemplary embodiment of the present invention. [Figure 6] FIG. 11 is an explanatory diagram showing a second exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] To carry out the method according to the invention, mills are used which are connected upstream of the actual rounding process and which not only pulverize the raw graphite but often also homogenize it, in the sense that the particle size differences in the graphite particle mixture to be subsequently spheroidized become less pronounced.

[0043] In the latter case in particular, a separator mill is preferably used as the upstream mill.

[0044] The separator mill referred to herein is a combination of a mechanical impact mill and an integrated dynamic air separator.

[0045] Such a separator mill is characterized in that a separator wheel rotates in a separator chamber, generating a strong circular vortex in the separator chamber. The graphite particles to be crushed are entrained in the circular vortex when they enter the separator chamber. As a result, particles that are still too large are subjected to a strong centrifugal force and are substantially held in an area sufficiently far radially from the separator wheel in order to release them into the separator wheel subject to the flow and from there to be transported out of the separator mill. While moving with the turbulent flow in the separator chamber, the graphite particles collide with the paddles and the collision surfaces and are crushed. Graphite particles that have become small enough after one or more crushings can no longer be kept permanently away from the separator wheel by the smaller centrifugal forces applied to them and are released by the flow into its interior and subsequently separated.

[0046] A separator mill particularly suitable for this application is the applicant's model CSM900.

[0047] Spheroidizing separator The rounding according to the present invention is characterized in that the graphite particles are repeatedly folded, thereby obtaining a round shape. In this case, some breakage (fracture) is essential. The breakage is not intended, but it cannot be completely avoided. However, it can be said that the graphite particles in particular do not obtain a round shape by the grinding process.

[0048] The broken pieces, together with other undersized particles that may have come from the pre-grinding, are expelled through the interior of the separator wheel to form the so-called fine material, which is characterized by being too small to produce the fine class of graphite material currently rounded in each spheronizing separator.

[0049] The general structure of the spheroidizing separator used according to the invention is a separator mill, but modified for use and / or for operation. The important modification is that the spheroidizing separator operates with a reduced process gas flow compared to a separator mill. The process gas flow of the spheroidizing separator is typically 30% to 10% by volume of the process gas flow in a separator mill having substantially the same structure.

[0050] Ideally, such a spheronizing separator is constructed substantially similarly to the subject matter of the present application and described in the applicant's DE 102020100907 A1.

[0051] However, according to the present invention, the spheroidized separators described in the above mentioned patent applications are preferably used in a structurally modified form, as will be explained in more detail below.

[0052] Importantly, the kinetic energy of rotation within the separator chamber of the spheroidizing separator is reduced compared to the operation of a separator mill to such an extent that the graphite material rotating within the separator chamber is primarily only folded and is not further pulverized by collisions with the positioned paddles and impact surfaces.

[0053] Nevertheless, in order to make the folding of the graphite particles as effective as possible, it has proven to be particularly advantageous when carrying out the method according to the invention to increase the height of the paddles 5, as is clearly shown in figure 3 (corresponding to figure 3B of DE 102020100907 A1), which results in a larger impact surface compared to the separator mill and the separator mill of DE 102020100907 A1 which is derived from it. Thus, when each paddle 5 rotates in the separator chamber while being held by the screw 30 and collides with the graphite particles, the surface available for a head-on collision is increased.

[0054] Ideally, the height of the paddles, depending on the type, is between 10 mm and 100 mm for separator mills and separator mills in DE 102020100907 A1 and is increased by 75% to 110% for spheroidizing separators according to the invention.

[0055] In this case, preferably more than 45% of the paddle height is located radially at the height of the vertical gap in the separator wheel through which the fine material is discharged.

[0056] The height of the impact surface 6 may be optionally adapted.

[0057] The enlarged paddle surface impacts more graphite particles per unit of time, re-rounding the particles a little. Thus, more energy can be applied per unit of time without making the individual impacts more forceful and causing unnecessary breakage. This allows rounding to be achieved more quickly. In batch processing, the processing time per batch is reduced.

[0058] Furthermore, it has proven advantageous to omit the cover ring 18, which is shown in particular on an enlarged scale in FIG. 3B of DE 102020100907 A1.

[0059] FIG. 3 shows the spheronization method as it has been implemented up to now by using a spheronization separator known from the present application DE 102020100907 A1 and which has also been popularized, probably in a more or less similar form, by Hosokawa Alpine GmbH, according to the description given above (which is the result of in-house tests on the subject).

[0060] Certain quality classes of commercially available spheroidized graphite materials (SPG) are manufactured in separate systems specially adapted for this purpose.

[0061] For example, the production of SPG20 and SPG10 graphite materials is performed in two systems that are constructed and operated completely independently of each other, as shown in FIG.

[0062] To produce graphite material of fine class SPG10, the raw graphite is separated by a separator mill 1, e.g. a Netsch CSM900. 50 = 10 μm, which makes the graphite particles small enough that, with the aid of one of the above-mentioned spheroidizing separators 2, a fine class SPG10 graphite material can be produced from this graphite by simple folding.

[0063] For this purpose, pre-crushed raw graphite 3 is placed in batches on the spheroidizing separator 2. The raw graphite rotates in the separator chamber for a given time, which is set so that the graphite particles remaining in the separator chamber are rounded at the end of the running time so as to meet the requirements of the quality SPG 10. During the rotation, fine material (thus particles too small for the SPG 10) is permanently removed and discharged via the separator wheel in the manner described above.

[0064] The same process is applied in a completely separate second line where fine class SPG20 graphite material is produced.

[0065] Using 1.233 kg / h of raw graphite gives a yield of 661 kg / h, hence a total yield of 46.4%.

[0066] The process according to the present invention differs as shown in FIG. JPEG2025031598000002.jpg58116

[0067] In this case, an upstream separator mill is used, usually a spheroidizing separator connected directly downstream of this separator mill, as well as a second spheroidizing separator also connected downstream of this spheroidizing separator. The two spheroidizing separators are preferably identical or of identical construction, but operated with different fine indicators (other operating parameters → speed, amount of gas; other separator wheel). In principle, the spheroidizing separators have the same construction and are operated identically, unless otherwise specified in the following description.

[0068] Ideally, in the realization of the invention, spheroidizing separators of the design described in DE 102020100907 A1 are used, and thus in the illustrated exemplary embodiment, ideally additionally with at least one of the modifications described above for DE 102020100907 A1.

[0069] In this case, the raw graphite is also pre-ground.

[0070] However, in this variant of the invention, the pre-grinding is at least substantially only to the particle size that the coarsest fine class of finished spherical graphite produced by the system should have, because the d 50 This is because a significant decrease in does not normally occur as part of spheroidization unless breakage occurs.

[0071] Therefore, in this case, the first useful product is this d 50In the case of spherical graphite, the 50 = 20 μm. No pre-grinding is carried out so intensively that the finer class of graphite material compared to the graphite produced in the first spheroidizing separator can be directly rounded only by one of the spheroidizing separators used here.

[0072] The separator mill 1 used for this pre-grinding is also ideally a Netzsch® CSM900.

[0073] According to the present invention, as described above, a number of spheroidizing separators 2a, 2b are arranged downstream of the separator mill 1. The first upstream spheroidizing separator 2a is provided with a fine class (e.g., d 50 Pre-ground raw graphite, suitable for use in a 20 μm feedstock, is preferably provided in batches.

[0074] Again, the placed raw graphite is rotated in the separator chamber for a predetermined time period, which is set so that the graphite particles remaining in the separator chamber are rounded at the end of the run time to meet the desired quality requirements, thus producing fine class SPG20 graphite material in this case.

[0075] An advantageous option may be that the separator wheel of the first spheronizing separator is configured to be 15% to 25% smaller in diameter than the separator wheel of the second spheronizing separator which is otherwise almost (at least substantially) structurally identical.

[0076] Particularly preferably, the first spheroidizing separator (or more precisely its paddle) is operated at a speed that varies during each batch processing, or starts from an initial speed of 100% at the beginning of the batch processing and decreases to 70%-40% of that, respectively, during the course of the batch processing, so that on the one hand the first spheroidizing separator can be controlled to actually produce the desired fine class of graphite material, and at the same time or alternatively, so that the first spheroidizing separator can be controlled to actually output, via the inside of its separator wheel, a type and / or amount of fine material that the second spheroidizing separator can carry out some processing on.

[0077] Fine material (i.e., particles that are too small for the SPG 20 in this example) is permanently removed during rotation in the manner described above, and is primarily made up of particles that were already too small after pre-grinding and particles that were broken and became too small during spheronization in the first spheronization separator.

[0078] According to the invention, the fine material is not discarded, but is placed directly or via an intermediate silo storage in the downstream spheroidizing separator 2b, which again subjects the placed material to the above-mentioned rounding by folding, as a result of which a finer fine class graphite material is produced, ideally several levels, ideally at least 5 full μm finer, than the previously produced fine class graphite material, in this case for example of the fine class SPG10. The fine material produced in this case is again removed via a separator wheel.

[0079] However, the second sphering separator (or its paddles), in contrast to the first sphering separator, is preferably operated at 100% speed throughout the entire batch process. In this case, it may be advantageous to reduce the amount of gas flowing through the second sphering separator by 10% to 40% by volume compared to the amount of gas flowing through the first sphering separator.

[0080] Finally, graphite material of the respective desired fineness is removed from the separator space in each spheroidizing separator, for example by the method described in DE 102020100907 A1.

[0081] For precise control of the process, advantageously only two spheronization separators are connected in series in the described manner, for processing larger masses such a system according to the invention usually has several connected in parallel.

[0082] The yields are significantly higher: when 960 kg / h of raw graphite is used, 435 kg / h of graphite material of fine class SPG20 and 167 kg / h of graphite material of fine class SPG10 are obtained, which corresponds to 62.8% of the total yield.

[0083] 6 shows a second exemplary embodiment of the present invention. Except for the differences specified below, the configuration corresponds to the first exemplary embodiment described above. Therefore, unless otherwise specified from the differences below, the above description is also applicable below. JPEG2025031598000003.jpg96166

[0084] The difference in this case is that only pre-ground coarser raw graphite is applied to the first spheroidizing separator 2a. The first spheroidizing separator of this system separates the coarsest specific fine class d 50 To produce the graphite, pre-milled raw material d 50 is preferably set to be 10% to 30% higher than each fine class. When fine class SPG22 graphite is produced as in the illustrated exemplary embodiment, a d of about 24 μm to about 28 μm is used. 50 This results in a higher pre-grinding throughput and a broader particle size distribution.

[0085] The first spheroidizing separator is then operated to produce a mixture of two fine classes, for example fine classes SPG18 and SPG22, of graphite material as product.

[0086] A further special feature of this exemplary embodiment is that the separator wheel of the first sphering separator 2a is configured with a smaller diameter than the separator wheel of the downstream sphering separator 2b, which in most cases rotates at a higher speed than the separator wheel of the downstream sphering separator.

[0087] This allows the separator space of the first spheroidizing separator 2a to absorb and round off the enlarged (in terms of mass) batch of pre-crushed graphite.

[0088] In the case of this exemplary embodiment, it is also particularly preferred that the first sphering separator 2a (or more precisely, its paddles) is operated at a speed that varies during each batch processing, which brings about the advantages mentioned above.

[0089] The described modifications of the separator wheel in the first spheroidizing separator 2a result in a reduction in its separation limit, although this is not an issue due to the additional separators 4, 5 (described below), which compensate for this "drawback", which allows the production of usable graphite material of different fine classes, for example powder classes SPG18 and SPG22, by ideally utilizing the raw graphite pre-ground and arranged to a lesser extent in the first spheroidizing separator 2a.

[0090] This product is discharged directly downstream from the first spheroidizing separator 2a. From here, the product is further processed in order to obtain a useful or final product. For this purpose, an additional first separator is used. In this case, the separator separates the rounded graphite particles, which essentially belong to the fine class SPG 18, from the product. Thus, part of the useful or final product is fine class 18 graphite material.

[0091] The remaining coarser graphite material resulting from the separation just described is fed to a separate further separator, in which the graphite material is again separated, i.e. into a batch of graphite material that is coarse enough to be fed again to pre-grinding, and a second batch of useful or final product forming fine class SPG22 graphite material.

[0092] The fine material removed through the inside of the separator wheel of the first spheroidizing separator 2a is not discarded, but instead, in the manner described above with respect to the first exemplary embodiment, this fine material is processed by the second spheroidizing separator 2b into an even finer fine class of graphite material, which as described above is often a few levels below the last produced fine class, for example fine class SPG10 graphite material in the illustrated embodiment.

[0093] In order to precisely control the process, even in the exemplary embodiment shown, only two spheronization separators are connected in series in the described manner, in order to process larger masses, several are usually connected in parallel in such a system according to the invention.

[0094] This method also results in a significant increase in yield.

[0095] When 894 kg / h of raw graphite is used, 137 kg / h of graphite material of fine class SPG22, 228 kg / h of graphite material of fine class SPG18 and 167 kg / h of graphite material of fine class SPG10 are obtained, which corresponds to 60% of the total yield. [Explanation of symbols]

[0096] 1. Separator Mill 2. Spheroidizing separator 2a First spheroidizing separator 2b Second spheroidizing separator 3 Pre-milled raw graphite 4 Additional First Separator 5 Additional Secondary Separator

Claims

1. A method for producing specific different fine classes of graphite particles rounded by impact effect using a plurality of spheroidizing separators connected in series, comprising: - pre-grinding the graphite material to be rounded; a first spheronizing separator then produces a spheronized first fine-class graphite material from said graphite material by folding and discharges said first fine-class graphite material as an end product in said process; At the same time, separating the graphite material that is too comminuted to be substantially processable into said first fine class of graphite material; feeding the separated graphite material, because it is too comminuted, to a second spheroidizing separator, which is capable of producing a second finer spheroidized graphite material from the separated graphite material by folding, and discharging the second finer spheroidized graphite material as an end product in the process; A method comprising:

2. 2. A method according to claim 1 for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that the intensity of pre-grinding or pre-grinding is set such that more than 50% by weight of the graphite material placed in the first spheroidizing separator is separated through the wheel of the first spheroidizing separator and then placed in a second separator producing a finer fine class of graphite material.

3. 3. A method according to claim 1 or 2 for producing graphite particles of different specific fine classes rounded by impact effect, comprising connecting two spheroidizing separators in series, each of said two spheroidizing separators producing a final product.

4. 4. A method according to any one of claims 1 to 3 for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that the fine material separated by the first spheroidizing separator is placed in the second spheroidizing separator without being separated and / or filtered again outside the first spheroidizing separator.

5. 5. A method according to any one of claims 1 to 4 for producing graphite particles of a specific different fineness class rounded by impact effect, characterized in that the product produced by rounding of the second spheroidizing separator downstream in the processing chain is a graphite material that is several fineness classes finer than the graphite material of the product produced by rounding of the first spheroidizing separator.

6. 6. A method according to any one of the preceding claims for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that the speed of the separator wheel of the first spheronization separator can be variably controlled in the processing chain during the batch process, and the speed of the separator wheel of the downstream second spheronization separator is preferably kept constant during the batch process.

7. 7. A method according to any one of the preceding claims for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that the diameter of the separator wheel in the first spheronization separator is smaller than the diameter of the separator wheel in the second spheronization separator downstream in the processing chain and / or the separator wheel in the first spheronization separator rotates faster than the separator wheel in the second spheronization separator downstream in the processing chain.

8. 8. A method according to any one of claims 1 to 7 for producing graphite particles of specific different fine classes rounded by impact effect, comprising: subjecting the pre-crushed raw graphite to the action of the first spheroidizing separator, d of the pre-crushed raw graphite 50 The first spheroidizing separator is to produce a product of the coarsest fine class d 50 The method according to claim 1, wherein the first and second sine waves are set to be 10% to 30% larger than the first and second sine waves.

9. 9. A method according to any one of the preceding claims for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that the first spheroidizing separator is operated in such a way that its target product is composed of graphite material of different fine classes, ideally SPG 18 and SPG 22, and is divided into ready-to-use graphite quantities.

10. 10. A method according to any one of claims 1 to 9 for producing specific different fine class graphite particles rounded by impact effect, characterized in that the first spheroidizing separator is operated in such a way that in addition to the fine class graphite material to be produced, the product also contains graphite particles, which are separated via an additional separator and then subjected again to pre-grinding for further grinding and placement again in the first spheroidizing separator.

11. 11. A method according to any one of the preceding claims for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that the speed of the separator wheel of the first spheronization separator can be variably controlled in the processing chain during the batch process, and the speed of the separator wheel of the downstream second spheronization separator is preferably kept constant during the batch process.

12. A method according to any one of the preceding claims for producing graphite particles of different specific fine classes rounded by impact effect, characterized in that at least one, preferably two, spheroidizing separators are used, the paddle surface of which is enlarged in such a way that the quotient of the net volume of the separator chamber and said paddle surface is between 0.5 and 2.

0.

13. A method according to any one of claims 1 to 12 for producing specific different fine classes of graphite particles rounded by impact effect, characterized in that the quotient of the net volume in the separator chamber and the envelope volume of the separator wheel is between 4.2 and 6.

5.

14. An apparatus for carrying out the method according to any one of claims 1 to 13, comprising a plurality of spheronizing separators.

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