Method for manufacturing graphite and vertical graphitization furnace

Abstract

In a process for producing graphite in a vertical graphitization furnace having at least one process chamber (22) demarcating a heating zone (28), the heating zone (28) is heated to a temperature of 2200°C to 3200°C, particularly 3000°C, a fine graphitization material (14) is supplied to the process chamber (22) through an inlet (30), the graphitization material (14) is transported through the heating zone (28) of the process chamber (22), graphitized into graphite, and the obtained graphite (12) is removed from the process chamber (22) through an outlet (40). As variant A, a graphitization material (14) having a particle size of less than 3 mm is used, and / or as variant B, a material column (94) is formed across the entire heating zone (28) of a specific material. After the graphitizable material (14) is supplied from the top through the inlet (30), it flows onto the material column (94) through the suction zone (24) of the process chamber (22), and / or as variant C, the material column (94) is formed in the fixed heating zone (98) of the specific process chamber (22) surrounded by the heating zone (28), where the graphitizable material (14) is supplied and then flows into the material column (94) and / or as variant D, the graphitizable material (14) through the drop heating zone (96) which is likewise surrounded by the heating zone (28). One or more material containers (100) are transported through the specific process chamber (22) and through the heating zone (28). Also, a vertical graphitization furnace (10) optimized particularly with respect to variants C and D is specified.

Description

Technology Field

[0001] The present invention relates to a method for producing graphite in a vertical graphitization furnace having at least one process space defining a heating zone, and

[0002] a) A temperature of 2200°C to 3200°C, particularly 2700°C or 3200°C, preferably 3000°C, is generated in a heating region;

[0003] b) A graphitizable particulate material is supplied into the process space through the inlet;

[0004] c) A graphitizable material is transported through a heating zone of a process space in which it is graphitized to produce graphite;

[0005] d) The acquired graphite is discharged from the process space through the outlet.

[0006] In addition, the present invention relates to a vertical graphitization furnace having at least one process space defining a heating zone, and

[0007] a) a heating device capable of generating a temperature of 2200°C to 3200°C, particularly 3000°C, in a heating area;

[0008] b) A supply conveyor capable of supplying graphitizable particulate material into a process space through an inlet;

[0009] Here,

[0010] c) A graphitizable material is transported through a heating zone of a process space that is graphitized to produce graphite;

[0011] d) There is an output conveyor through which the obtained graphite can be discharged from the process space through the outlet. Background Technology

[0012] The graphitization of graphitizable materials is carried out in an inert gas atmosphere. Polycrystalline graphite used as an anode material is known to be produced by a batch process in a so-called Acheson furnace, where graphitizable materials are graphitized to provide graphite.

[0013] In addition, it is known in EP 2 980 017 B1 that graphitizable materials having large particle diameters of more than 3 mm are made into graphite in a vertical graphitization furnace of the type initially mentioned. After this process, the obtained graphite, having particles too large for an anode material, is crushed to obtain graphite powder. The problem to be solved

[0014] The object of the present invention is to provide a vertical graphitization furnace and method of the type mentioned in the introduction that enables energy-efficient, generally consistent, and reproducible graphite quality. means of solving the problem

[0015] This objective is achieved in the type of process mentioned in the introduction, and

[0016] These use, with variation A, particles of a graphitizable material having a particle size of less than 3 mm; and / or

[0017] In variant B, a column of graphitizable material is formed in the entire heating zone of a specific process space, and said graphitizable material is supplied through said inlet and flows from said top through the inlet zone of the process space into said column of material; and / or

[0018] In variant C, a column of material is formed in a static heating zone of a specific process space, said static heating zone is surrounded by said heating zone, and a graphitizable material supplied through an inlet flows from the top through a downward heating zone into the column of material, said downward heating zone is likewise surrounded by said heating zone; and / or

[0019] In deformation D, the graphitizable material passes through a specific process space into one or more material containers and is transported through the heating zone.

[0020] According to the present invention, it has been recognized that the above objective is achieved in the type of process mentioned at the beginning by a number of approaches that contribute to a more effective process procedure compared to the prior art when used alone or in a synergistic combination, or when a graphitization furnace having multiple process spaces is used simultaneously. Since deformations A, B, C, and D may be performed in parallel, each case may be referred to following the cases of deformations B, C, and D and the "specific" process space. This is intended to express the fact that in the case of multiple process spaces within the furnace, one specific process space is considered. This may also be a process space where other deformations proceed, provided that they can proceed simultaneously, but not necessarily; this is not possible in the case of deformations B and C.

[0021] Variant A makes it possible to omit the subsequent grinding of the obtained graphite in the most advantageous cases. In any case, the cost for satisfactory grinding can be reduced.

[0022] Variant B allows for a continuous process in a defined atmosphere.

[0023] In variant C, the type of preheating can occur in the descending heating zone, thereby reducing the energy consumption for heating the column of material formed from the already preheated graphitizable material.

[0024] In deformation D, a smaller volume is graphitized within the material container, and as a result, process control is improved.

[0025] To achieve a consistently controllable process, it is advantageous to supply the volume of graphitizable material into a specific process space per unit time in a manner equal to the volume of graphite discharged from the process space per unit time.

[0026] A graphitizable material can be supplied continuously or intermittently into a specific process space, and graphite can be discharged continuously or intermittently from this process space; preferably, continuous supply and discharge are provided. In the case of an intermittent process, supply and discharge can be performed simultaneously or with a temporal offset.

[0027] To reproducibly perform process deformations B and C, it is advantageous to maintain the filling level of the material column largely constant for deformation B and / or deformation C.

[0028] In the case of deformation C, to control and monitor preheating, it may be advantageous to blow gas into the descending heating zone in a direction opposite to or opposite to the flow of the graphitizable material in the descending direction.

[0029] As mentioned above, it is possible to use a graphitization furnace having multiple process spaces in which the multiple process spaces operate in parallel over time.

[0030] In relation to deformation A, it is advantageous for the particles of the graphitizable material to have an average particle diameter greater than 5 μm and less than 3000 μm, less than 2500 μm, less than 2000 μm, 1500 μm, 1000 μm, or less than 500 μm, or for the particles of the graphitizable material to have an average particle diameter of 5 μm to 3000 μm, 500 μm to 2000 μm, or 1000 μm to 1500 μm.

[0031] For effective operation, it is advantageous to determine the temperature of the heating zone, particularly at the top of the heating zone and / or approximately in the middle of the heating zone and / or at the bottom of the heating zone, and / or in the column of material of each existing process tube. In this way, temperature fluctuations in the heating zone can be rapidly accounted for by controlling the heating device in a manner that compensates for undesirable temperature changes.

[0032] In the vertical graphitization furnace of the type mentioned earlier, the purpose is...

[0033] e) A heating zone within one or more process spaces comprising a descending heating zone and an upright heating zone configured such that a column of material is formed in an upright heating zone so that a graphitizable material supplied through an inlet can flow from the top through a descending heating zone into a column of material;

[0034] and / or

[0035] f) A transport system exists, and the graphitizable material can be transported by the transport system through one or more process spaces and their heating zones within one or more material containers.

[0036] This optimizes the graphitization furnace, particularly in relation to process variants C and D.

[0037] In this case, it is advantageous for the conveying system for the supply conveyor and the output conveyor to be configured to convey containers for materials containing materials, and for the conveying system to include a process space conveyor configured to convey containers for materials from the inlet to the outlet.

[0038] The vertical graphitization furnace can operate particularly effectively when the transport system is a loop transport system and additionally includes a connecting conveyor through which a container for material can be transferred from an output conveyor to a supply conveyor.

[0039] The container for the material is advantageously a crucible having a crucible lid.

[0040] As mentioned above, it is advantageous for multiple process spaces to exist within the graphitization furnace.

[0041] In addition, a temperature monitoring device is preferred, thereby making it possible to determine the temperature of the heating zone, particularly at the top of the heating zone and / or approximately in the middle of the heating zone and / or at the bottom of the heating zone, and / or in the column of material of each existing process tube. Effects of the invention

[0042] According to the present invention, the advantage is provided that energy-efficient, generally consistent, and reproducible graphite can be obtained. Brief explanation of the drawing

[0043] Exemplary embodiments of the present invention will be described in more detail below based on the drawings. FIG. 1 illustrates a vertical graphitization furnace according to a first embodiment of the present invention, wherein a graphitizable material is transported downward from the top through a process space as a column of material, and a first method of performing the process is illustrated. FIG. 2 illustrates the vertical graphitization furnace of FIG. 1 and a second method for performing the process. FIG. 3 illustrates a vertical graphitization furnace according to a second exemplary embodiment having two process spaces driven in parallel. FIG. 4 illustrates a variation of the exemplary embodiment of FIG. 3, wherein the process spaces driven in parallel are spaced apart from each other. FIG. 5 illustrates a vertical graphitization furnace according to a third exemplary embodiment having a transfer system for a material container in which a graphitizable material is located. Specific details for implementing the invention

[0044] FIG. 1 illustrates a vertical graphitization furnace (10) used to produce polycrystalline graphite (12) for an anode material, which will hereinafter be simply referred to as the furnace (10). A finely graphitizable material (14) serves as a starting material for the production of polycrystalline graphite (12). The graphitizable material contains carbon, and the conversion of amorphous carbon into polycrystalline graphite occurs during graphitization. Examples of graphitizable materials are brown coal or hard coal and optionally also polymers.

[0045] The particles of the graphitizable material (14) preferably have a particle size of less than 3 mm. The particles of the graphitizable material (14) preferably have an average particle diameter greater than 5 μm and less than 3000 μm, less than 2500 μm, less than 2000 μm, less than 1500 μm, less than 1000 μm, or less than 500 μm. As another example, the particles may have an average particle diameter of 5 μm to 3000 μm, 500 μm to 2000 μm, or 1000 μm or 1500 μm.

[0046] The furnace (10) includes a process tube (16) having an outer tube wall (18) made of graphite, and the outer tube wall accommodates a process space (22) that defines an inlet zone (24) vertically arranged at the top in the inner space (20), an outlet zone (26) vertically arranged at the bottom, and a heating zone (28) arranged between them in which particles of a graphitizable material (14) are graphitized to provide graphite (12).

[0047] Accordingly, the upper end (28a) of the heating zone (28) is defined as the transition from the inlet zone (24) to the heating zone (28); and the lower end (28b) of the heating zone is defined as the transition of the heating zone portion (28) to the outlet zone (26) accordingly. The internal space (20) or process space (22) preferably has a circular cross-section. However, alternative cross-sections, such as elliptical, square, or rectangular, are also possible. Generally, the outer tube wall (18) represents the shape of the cross-section of the internal space (20) or process space (22) and has a corresponding outer cross-section, but this may also differ.

[0048] The inlet section (24) of the process tube (16) is connected to the outlet side (32) of the supply conveyor (34) for the graphitizable material (14) at the inlet (30), and the inlet side (36) is supplied with the graphitizable material (14) from the storage (38) of the graphitizable material. In this exemplary embodiment, the supply conveyor (34) is configured to transport the graphitizable material (14) itself and is configured as a screw conveyor, as is particularly known for this purpose. The outlet section (24) of the process space (22) is connected to correspond to the inlet side (42) of the output conveyor (44) at the outlet (40), and the graphite (12) produced thereby is collected and discharged at the outlet section (26). In this exemplary embodiment, the output conveyor (44) is configured to transport the graphite (12), and for this purpose, the output conveyor is likewise configured as a screw conveyor. However, it is additionally cooled with the help of a water cooling system, which is likewise known itself.

[0049] The supply conveyor (34) and output conveyor (44) are configured in such a way that a gastight connection to the process tube (16) can be formed and transport can be carried out while excluding the inflow of ambient atmosphere. For example, alternative transport concepts such as a double flap system combined with a conveyor belt or a vibratory chute, a star feeder, etc., are also possible for this purpose.

[0050] In the area of ​​the heating zone (28), the process space (16) is heated to about 2200°C to about 3200°C, preferably about 3000°C, by a heating device (46) for the graphitization process, which is indicated in the drawing as the dark hatched area of ​​the process tube (16). In practice, the heating device (46) is an electric heating device. For example, the wall thickness of the process tube (16) is reduced in the area of ​​the heating zone (28) for this purpose, and accordingly, due to higher electrical resistance, the process tube is heated more effectively. The heating zone (28) is defined by an adjacent section of the process space (22) where essentially the same graphitization temperature predominates.

[0051] The process tube (16) extends through a through opening (48) in the upper cover wall (50) and, for example, through a through opening (52) in the lower bottom wall (54) of the insulation housing (56) made of steel plate, such that the upper portion (16a) of the process tube (16) protrudes upward and the lower portion (16b) of the process tube protrudes downward from the insulation housing (56). Plate-shaped insulation elements (58), preferably made of hard graphite felt, are arranged on the inner side of the cover wall (50) and the bottom wall (54), in each case, and the passage (60) is formed stepped along the axial direction of the process tube (16), defining a stepped area (62) in each case. Each area of ​​the stepped passage (60) having a small cross-section faces the cover wall (50) or the bottom wall (54) of the insulation housing (56), and the stepped areas (62) face each other. The insulating element (58) can be manufactured as a single piece or formed by two plate-shaped elements having through openings of different diameters, so that the stepped passage (60) is formed as a whole.

[0052] A protective housing (64) made of graphite for a process tube (16), for example, a protective tube, extends from a stepped area (62) of an insulating element (58) on the cover wall (50) to a stepped area (62) of an insulating element (58) on the bottom wall (54), in such a way that an annular space (66) is formed between the process tube and the protective housing, which is opened at the top and bottom, respectively, in the direction of through openings (48 and 52) of the cover wall (50) and the bottom wall (54).

[0053] An insulating ring space (68), bordered by a protective housing (64), an insulating housing (56), and insulating elements (58), is formed radially next to the protective housing (64). In this exemplary embodiment, this insulating ring space (68) is filled with carbon black.

[0054] The through opening (48) of the cover wall (50) is covered by an upper connecting cap (70). In this exemplary embodiment, the upper portion (16a) of the process tube (16) extends through the upper connecting cap (70) so that an upper annular connecting space (72) is formed between the cover wall (50) of the insulating housing (56) and the inlet (30) of the process tube; and this annular connecting space (72) is fluidly connected to the annular space (66) through the through opening (48), the cover wall (50), and the passage (60) of the upper insulating element (58).

[0055] In a corresponding manner, the through opening (52) of the bottom wall (54) is covered by the lower connecting cap (74). In this exemplary embodiment, the lower portion (16b) of the process tube (16) extends through the lower connecting cap (74) so ​​that a lower annular connecting space (76) is formed between the bottom wall (54) of the insulating housing (56) and the outlet (40) of the process tube (16); this annular connecting space is fluidly connected to the annular space (66) through the through opening (52) of the bottom wall and the passage (60) of the lower insulating element (58).

[0056] In the upper and lower transition sections between the insulating housing (56) and the connecting caps (70, 74), there is a housing cooling device (78) for protecting the housing element designed as a water cooling system as is known in itself.

[0057] The passage (60) of the ring-shaped connecting space (72 and 76), the ring-shaped space (66), and the insulation element (58) forms a gas space (80) that is part of the protective gas system (82).

[0058] The protective gas system (82) further includes a first protective gas inlet connection (84.1) on the upper connecting cap (70) and a second protective gas outlet connection (84.2) on the lower connecting cap (74), thereby enabling the protective gas to be blown into the gas space (80).

[0059] Because the insulating element (58) is porous and therefore gas permeable, the protective gas diffuses from the gas space (80) into the area of ​​the passage (60) having a smaller cross-section and into the insulating annular space (68). On the cover wall (50) of the insulating housing (56), there is a protective gas outlet connection (86) so that the protective gas can be discharged. To assist, a third protective gas inlet connection (84.3) is also present on the bottom wall (54) of the insulating housing (56) so that the protective gas can also be blown into the insulating annular space (66) in a desired manner.

[0060] A protective gas around the process tube (16) is required because the graphitization of the graphitizable material (12) occurs under an inert gas atmosphere present in the process space (22). As the protective gas, a gas identical to the inert gas is generally used, so that the same type of gas is present on both sides of the outer tube wall (18) of the process tube (16). However, different gases may also be used as the protective gas and as the inert gas, and the protective gas must also be inert. For example, argon, nitrogen, or helium, or a mixture thereof, may be used as the protective gas and / or inert gas.

[0061] To introduce an inert gas into the process space (22), the process tube (16) is coupled to an inert gas inlet connection (88) at the bottom portion (16b), thereby allowing the inert gas to be introduced into the process chamber (22). The top portion (16a) of the process tube (16) is connected to an off-gas outlet connection (90), so that the gas formed in the graphitization performed by mixing with the inert gas can be discharged as off-gas from the process space (22). In this case, the furnace (10) is operated in reverse flow accordingly, and the inert gas flows through the process space in a direction opposite to the direction of movement of the material present in the process space (22). Alternatively, the inert gas inlet connection (88) may be arranged in the top portion section (16a) of the process tube (16), and the off-gas outlet connection (90) may be arranged in the bottom portion section (16b) of the process tube (16, 16b). In additional variations, in each case, the inert gas inlet connection and the off-gas outlet connection may be connected to the process space (22) at both the upper and lower ends, so that graphitization may optionally be performed countercurrently or concurrently by appropriate switching. The off-gas is provided to a thermal post-combustion stage as known in each case.

[0062] In another variation, the gas supply tube may be guided from an inert gas inlet connection (88) arranged in an upper end section (16a) downwardly above the filling level (92) of the column of material (94), so that the inert gas is blown into the processing space (22) above the column of material (94).

[0063] Transport components such as blowers and gas pumps required for the transport of shielding gas, inert gas, or off-gas, as well as related conduits and control devices, are not depicted individually for the sake of simplification.

[0064] No (10) operates as follows:

[0065] Before initial startup, the process space (22) and the process space atmosphere present therein must first be free of oxygen and moisture, particularly from the air present therein. To this end, the process space (22) is flushed with an inert gas, and the gas space (80) and also the insulating ring space (68) are flushed with a protective gas.

[0066] When the heating device (46) is activated, the graphitizing material (14) is supplied into the process space (22) to the filling level (92) by the supply conveyor (34). When the output conveyor (44) is activated, it first transports the incompletely reacted material out of the process space (22) until the graphite (12) obtained in the heating zone (28) reaches the output conveyor.

[0067] In the ongoing graphitization process, the graphitizable material (14) is continuously supplied into the process space (22) by the supply conveyor (34), and the graphite (12) obtained therefrom is continuously removed from the processing space (20) by the output conveyor (44). Here, since the volume of the graphitizable material (14) is supplied per unit time, that is, possibly per minute, equal to the volume of the graphite (12) discharged per unit time, the fill level (92, fill level) in the process tube (92) is maintained at a generally constant level. Thus, in terms of material management, the illustrated furnace (10) is operated continuously.

[0068] In a modified example, the furnace (10) is operated intermittently in terms of material management. In this case, the graphitizable material (14) is continuously supplied into the process space (22) by the supply conveyor (34) simultaneously with supply and discharge, and the graphite (12) obtained therefrom is simultaneously and continuously removed from the process space by the output conveyor (44) when a material replacement operation is performed in which a specific volume of graphite (14) is extracted and replaced by a corresponding volume of graphitizable material (12).

[0069] In continuous operation, the conveying speeds of the supply conveyor (34) and the output conveyor (44) are set such that, in any case, the residence time of the graphitizable material (14) in the heating zone (28) at approximately 3000°C is approximately 2 to 3 hours. Graphite (12) that is no longer mixed with the graphitizable material may already be present in the lower region of the heating zone (28).

[0070] At a temperature in a heating zone (28) of about 2700°C, the residence time of the graphitizable material (14) may be about 10 to 20 hours.

[0071] FIG. 1 illustrates a process procedure in which the filling level (92) within the process tube (16) corresponds to the height level of the upper portion (28a) of the heating zone (28). In other words, a column (94) of material extending downward from the filling level (92) and also through the exit zone (26) to the exit (40) of the process tube (16) is formed in the entire heating zone (28). In contrast, the inlet zone (24) is passed only by the graphitizable material (14), which is supplied into the process space (22) through the inlet (30) and then trickles from the top onto the material column (94) to become part of the material column (94). The term “trickle” is intended here as a general term for material falling downward without any relation to possible technical parameters such as the fluidity of the bulk material.

[0072] FIG. 2 illustrates an alternative method of performing the process in which the filling level (92) is located below the upper end (28a) of the heating zone (28). Thus, a column of material (94) is not formed in the entire heating zone (28). Rather, the graphitizable material (14) enters from the top of the inlet zone (24) and flows or descends onto the column of material (94) through the descending heating zone (96), and the descending heating zones (96) that reach the column of material and become part of the column of material are formed between the column of material, i.e., the filling level (92) and the upper end (28a) of the heating zone (28). Thus, the graphitizable material (14) passes through the descending heating zone (94) while descending or descending from the top.

[0073] In the operating mode described herein, the falling heating zone (96) is a type of free-fall heating zone through which the graphitizable material (14) free-falls downward from the top. Here, the counter-flow of the atmosphere within the process tube (16) in the direction of the off-gas outlet connection (90) can delay the fall of particles of the graphitizable material (14) compared to free fall, and thus increase the residence time in the falling heating zone (96). In the variation discussed above where the off-gas outlet connection (90) is provided at the bottom of the process tube (16), the gas stream can consequently accelerate the fall of particles of the graphitizable material compared to free fall, thereby reducing the residence time in the falling heating zone (96).

[0074] In a variant not individually illustrated, the inert gas may be selectively blown in a reverse flow or downward flow toward the downward heating zone in a targeted manner to intentionally delay or accelerate the downward velocity of the particles of the graphitizing material (14) in order to set the residence time in the downward heating zone (96) in a targeted manner.

[0075] The area of ​​the heating zone (28) where the column of material (94) is formed defines a standing heating zone (98) surrounded by the heating zone (28). The term “standing” is intended to indicate that the column of material (94) remains largely in a standing state, even if the column of material (94) changes due to the introduction and discharge of material during the operation of the furnace (10). At least essentially the same temperature prevails in the descending heating zone (94) and the standing heating zone (98).

[0076] In the descending heating zone (94), the graphitizable material (14) is already heated, while the graphitizable material flows into the material column (94) at a higher initial temperature than in the case of the material column (90) where the filling level (92) is already formed at the upper part (28a) of the heating zone (28). As a result, the particles of the graphitizable material (14) can obtain the temperature required for graphitization more quickly.

[0077] In the variation illustrated in FIG. 2, the descending heating zone (96) and the stationary heating zones (98) each occupy about 50% of the heating zone (28). In practice, effective graphitization could be achieved in a furnace (10) in which the descending heating zone (96) occupies 10% to 60%, preferably 20% to 55%, more preferably 30% to 50%, particularly 30% or the illustrated 50% of the heating zone (28).

[0078] FIG. 3 illustrates a furnace (10) according to a second exemplary embodiment in which two process tubes (16.1, 16.2) extend through an insulating housing (56). This exemplary embodiment also illustrates additional variations in which more than two process tubes (56) exist and extend in a corresponding manner through an insulating housing (56).

[0079] In FIG. 3, for brevity, not all components and parts are provided with reference numerals, and labeled components and parts corresponding to the components and parts in FIG. 1 and 2 are provided with the same reference numerals, and connection with the first process tube (16.1) or the second process tube (16.2) is optionally indicated by the corresponding index .1 or .2.

[0080] The protective housing (64) here surrounds the two process tubes (16.1, 16.2), but it is also possible to assign a separate protective housing to each process tube (16.1, 16.2).

[0081] FIG. 3 also illustrates process tubes (16.1, 16.2) in contact with each other, but in one variation illustrated in FIG. 4, the process tubes (16, 16, 2) may also be separated from each other by a certain distance, so that carbon black is also placed between the process tubes; and the annular space (68) is appropriately modified. Accordingly, the peripheral housing and the associated passage and opening are modified. Thus, two protective housings (64) and annular spaces (66) exist, and likewise two upper connecting caps (70) and two lower connecting caps (74) exist, and all components do not form their respective reference numerals twice in the drawings.

[0082] In the exemplary embodiment illustrated in FIG. 3, each process tube (16.1, 16.2) is assigned to a separate supply conveyor (34.1 and 34.2) in each case and to a separate output conveyor (44.1 or 44.2) in each case. In one variation, there may be only a single supply conveyor (34) that supplies material to both process tubes (16.1, 16.2). Accordingly, there may be only a single output conveyor (44) that absorbs and releases graphite (12) from both process tubes (16.1, 16.2).

[0083] In the case where there are more than two process tubes (16), a single supply conveyor (34) can supply graphitizable material (14) to only one, a pair, or a group of three or more process tubes (16) and optionally all process tubes (16). Correspondingly, in the case of more than two process tubes (16), a single output conveyor (44) can acquire and discharge graphite (12) obtained from only one, a pair, or a group of three or more process tubes (16) and optionally all process tubes (16).

[0084] When separate supply conveyors (34.1 and 34.2) and separate output conveyors (44.1 or 44.2) are assigned to each of the two process tubes (16.1, 16.2), different graphitizable materials (14) requiring different residence times in each heating zone (28.1, 28.2) or standing heating zone (98) may be supplied to the process tubes (16.1, 16.2), the latter being shown only in FIG. 3 as a standing heating zone (98.2) in the case of the process tube (16.2). This illustrates that the different process tubes (16.1, 16.2) may also be operated in different modes of operation.

[0085] Regardless of the total number of process tubes (16), the heating zones (28.1 and 28.2) of two different process tubes (16.1, 16.2) may have the same or different lengths. When the process tubes (16.1, 16.2) are each operated as a downward heating zone (96), the length of the process tube and the corresponding ratio of the lengths of the downward heating zone and the upright heating zone may also be different.

[0086] FIG. 5 illustrates a third exemplary embodiment of a furnace (10), wherein the graphitizable material (14) is not introduced into the process space (22) as a bulk or fluidizable material, but instead is transported within a container (100) for the material through the process space and through the heating zone (28). As a container (100) for the material having only three reference numerals, a crucible (102) having a crucible cover (104) is provided in this exemplary embodiment. A transport system (106) is configured such that a carrier (100) for the material filled with the graphitizable material (14) can be transported along a path through an inlet (30) to the process space (22), from there to an outlet (40) through the process chamber (22), and out of the process chamber through the outlet (40).

[0087] For this purpose, the transfer system (106) includes a supply conveyor (34) and an output conveyor (44), and in this exemplary embodiment, the supply conveyor is configured to transfer a material container (100) containing material. Additionally, the transfer system (106) includes a process space conveyor (108), which is configured to transfer a material container (100) containing material in the process space (22) and to transfer a material container from an inlet (30) to an outlet (40).

[0088] Additionally, the transport system (106) in the present exemplary embodiment is designed as a loop transport system and includes a connecting conveyor (110) for this purpose, and the material container (100) can be transported from the output conveyor (44) to the supply conveyor (34) by the connecting conveyor.

[0089] The supply conveyor (34) and the output conveyor (44) are designed as rotary conveyors (112 and 114) each comprising a rotary element (116 and 118) that can be rotated around a vertical rotation axis (120). The process space conveyor (108) and the connecting conveyor (110) are designed as linear conveyors (122 and 124), and for this purpose, a pushing device (126) having a powered pushing element (128) in the form of a push rod is present in each case. In the case of the process space conveyor (108), the pushing element (128) pushes a material container (100) that has entered the process space (22) into the inlet area (24). Then, this material container (100) strikes a material container located below it, and as a result, all material containers present in the process space (22) are pushed one by one. To function this way, an empty location without a material container (100) exists at this point at the exit (40) of the process space (22).

[0090] When the material container (100) passes through the heating zone (28) on the path passing through the process space (22), the graphitizable material (14) is graphitized to provide graphite (12). The material container (100) at the outlet (40) consequently contains graphite (12). When the material container (100) arrives at the outlet (40) of the process tube (16), an empty position is formed at the inlet (30), so that the material container loaded with the graphitizable material (14) can be transported to the process space (22) by the supply conveyor (34). Here, at the end of the transport path of the connecting conveyor (110), an empty position is created on the supply conveyor (34), and the empty container (100) for the material is pushed into it by the connecting conveyor, which operates in the same manner as the process space conveyor (108). The empty space occurring at the entrance of the connecting conveyor (110) is filled into an empty material container (100) by the output conveyor when the output conveyor (44) takes the material container (100) loaded with graphite (12) from the process tube (16).

[0091] The supply conveyor (34) includes a filling station (130), and the empty material container (100) can be filled with graphitized material (14) by the filling station. The output conveyor (44) includes an emptying station (132), and graphite (12) can be obtained from the material container (100) at this emptying station. A suitable lock design is used here to prevent contamination of the furnace atmosphere by an external atmosphere.

[0092] In the situation illustrated in FIG. 5, the rotational elements (116, 118) on the four receiving positions for the material container (100) are designed so that a rotation of 90° around the rotation axis (120) is performed at each stage. In this case, the empty material container (100) reaches the filling station (130) one stage before the inlet (30) of the process tube (16), and the material container (10) filled with graphite (12) reaches the emptying station (132) one stage after the outlet (40) of the process tube.

[0093] In the process space (22), the material container (100) is transported intermittently in the case of the furnace (10) described as a result. In one variation and by a correspondingly designed transport system (106), the material container (100) can also be transported continuously within the process space (22).

[0094] In all the exemplary embodiments described above, the temperature within the heating zone (28) or the temperature of the column (94) of the material is monitored by a temperature monitoring device.

[0095] For this purpose, the temperature is determined at the upper end (28a) of the heating zone (28) of each existing process tube (16) and / or approximately the middle of the heating zone (28) and / or the lower end (28b) of the heating zone 28.

[0096] Alternatively, or additionally, a temperature measurement may be taken above the filling level (92) of the column of material (94).

[0097] Temperature measurement is preferably performed using a pyrometer having a pyrometer tube as is known by itself, and the measuring end of the pyrometer tube is arranged at each measurement location. The measurement is preferably performed from the side of the heating device (46).

[0098] For measurement in the heating zone (28), the pyrometer tube reaches the annular space (66) in front of the outer tube wall (18) of the process tube (16), for example, from the outside through the outer wall of the insulating housing (56) and also through the insulating annular space (66) and through the wall of the protective housing (64). The relevant pyrometer is located at the free end of the pyrometer tube outside the protective housing (56). The corresponding pyrometer tube is preferably arranged horizontally. From the temperature determined in this way outside the process tube, the temperature

[0099] When a measurement is performed from the top at the filling level (92) of the column of material (94), the pyrometer tube extends from the top into the process tube (16) up to just above the filling level (92). After that, it is preferable for the pyrometer tube to extend vertically, and accordingly, the pyrometer is positioned at the top of the pyrometer tube. However, a horizontal arrangement of the pyrometer tube is also possible. However, in this case, the pyrometer tube also penetrates the outer tube wall (18) of the process tube (16) and opens into the process space (22). Explanation of the symbols

[0100] 10: No 14: Graphitizable material 44: Output conveyor 12: Polycrystalline graphite 42: Entrance side 16: Process tube 46: Heating device 16a: Top part 48: Through opening 16b: Bottom section 50: Top cover wall 18: Outer tube wall 52: Penetration opening 24: Entrance area 54: Lower floor wall 26: Exit Zone 56: Insulated Housing 28: Heating zone 58: Insulation element 22: Process space 60: Staircase passageway 28a: Upper end 62: Stair area 28b: Lower end 64: Protective housing 20: Interior space 66: Ring space 30: Entrance 68: Insulated ring space 32: Outlet side 70: Upper connecting cap 34: Supply conveyor 72: Upper ring-shaped connecting space 36: Inlet side 74: Lower connecting cap 38: Storage 76: Lower ring-shaped connection space 40: Outlet 78: Housing cooling device 80: Gas space 120: Rotation axis 82: Protective gas system 122, 124: Linear conveyor 84.1: First protective gas inlet connection 126: Pushing device 84.2: Second protective gas outlet connection 128: Pushing element 84.3: Third protection gas inlet connection 130: Charging station 86: Protection gas outlet connection 132: Emptying station 88: Inert gas connection 102: Crucible 90: Off-gas outlet connection 104: Crucible cover 92: Charging Level 106: Transport System 94: Material Column 108: Process Space Conveyor 96: Lowering heating zone 110: Connecting conveyor 98: Stop heating zone 116, 118: Rotating element 100: Material container 112, 114: Rotary conveyor

Claims

Claim 1 A method for producing graphite in a vertical graphitization furnace comprising at least one process space defining a heating zone, wherein the method comprises: a) a temperature of 2200°C to 3200°C is formed in the heating zone; b) a graphitizable material in the form of particles is provided to the process space through an inlet; c) the graphitizable material moves through the heating zone of the process space, wherein the graphitizable material is graphitized in the heating zone to produce graphite; d) the obtained graphite is discharged through an outlet in the process space; e) the process space is disposed within the internal space of a process tube having an outer wall made of graphite, wherein the process tube is heated by an electric heating device due to the electrical resistance of the process tube in the heating zone; ea) wherein, with variation A, particles of the graphitizable material having a particle size of less than 3 mm are used; eb) in variant B, a column of a graphitizable material is formed in the entire heating zone of a specific process space, and the graphitizable material is supplied through the inlet and flows from the top through the inlet zone of the process space into the column of the material; ec) in variant C, a column of material is formed in the stationary heating zone of a specific process space, the stationary heating zone is surrounded by the heating zone, and the graphitizable material supplied through the inlet flows from the top through the descending heating zone into the column of the material, and the descending heating zone is likewise surrounded by the heating zone; ed) in variant D, the graphitizable material passes through the specific process space to one or more material containers and is transported through the heating zone, and is a method characterized by at least one of ea), eb), ec), and ed). Claim 2 A method according to claim 1, characterized in that a temperature of 2700℃ to 3200℃ is formed in the heating zone. Claim 3 A method according to paragraph 2, characterized in that a temperature of 3000℃ is formed in the heating zone. Claim 4 A method according to claim 1, characterized in that the volume of graphite discharged from the process space per unit time is equal to the volume of graphitizable material supplied to the specific process space per unit time. Claim 5 A method according to any one of claims 1 to 4, wherein a graphitizable material is supplied continuously or intermittently to a specific process space, and graphite is discharged continuously or intermittently from this process space. Claim 6 A method according to claim 1, characterized in that the filling level of the column of material is constant in the case of deformation C and / or deformation B. Claim 7 A method according to claim 1, characterized in that, in deformation C, the graphitizable material flows gas in a direction opposite to or in the same direction as the downward direction toward the downward heating zone. Claim 8 A method according to claim 1, characterized by using a graphitization furnace comprising a plurality of process spaces and wherein the plurality of process spaces operate in parallel over time. Claim 9 A method according to claim 1, wherein the graphitizable material has an average particle diameter greater than 5 μm and less than 3000 μm, less than 2500 μm, less than 2000 μm, less than 1500 μm, less than 1000 μm, or less than 500 μm, or the particles of the graphitizable material have an average particle diameter from 5 μm to 3000 μm, from 500 μm to 2000 μm, or from 1000 μm to 1500 μm. Claim 10 A method according to claim 1, characterized in that the temperature of the heating zone is determined. Claim 11 A method according to claim 10, characterized in that the temperature is determined at one or more of the upper part of the heating zone, the middle part of the heating zone, the lower part of the heating zone, and the column of material of each existing process tube. Claim 12 A vertical graphitization furnace having at least one process space defining a heating zone, wherein the vertical graphitization furnace comprises: a) a heating device that generates a temperature of 2200°C to 3200°C in the heating zone; b) a supply conveyor that supplies a graphitizable material in the form of particles into the process space through an inlet; c) a graphitizable material that can be supplied through the heating zone of the process space where graphitization occurs to produce graphite; d) an output conveyor that discharges the obtained graphite from the process space through an outlet; e) the process space is disposed within the internal space of a process tube having an outer wall made of graphite, and the process tube is heated by an electric heating device in the heating zone due to the electrical resistance of the process tube; ea) the heating zone within at least one process space includes a downward heating zone and a stationary heating zone, wherein the stationary heating zone is configured such that a column of material is formed within the stationary heating zone, and the downward heating zone is configured such that the graphitizable material supplied through the inlet flows from the top through the downward heating zone into the column of material. A vertical graphitization furnace comprising; eb) having a transport system capable of transporting a graphitizable material through at least one process space and its heating zone to one or more material containers. Claim 13 A vertical graphitization furnace according to claim 12, characterized in that a temperature of 3000°C is generated in the heating zone by the heating device. Claim 14 A vertical graphitization furnace according to either claim 12 or 13, wherein the supply conveyor and the output conveyor are configured to transport a material container containing material, and the transport system comprises a process space conveyor configured to transport the material container from the inlet to the outlet. Claim 15 A vertical graphitization furnace according to claim 14, wherein the transport system is a loop transport system and includes a connecting conveyor that allows a material container to be transported from the output conveyor to the supply conveyor. Claim 16 A vertical graphitization furnace according to any one of claims 12 to 13, characterized in that the material container is a crucible having a crucible cover. Claim 17 A vertical graphitization furnace characterized by the existence of a plurality of process spaces in any one of claims 12 to 13. Claim 18 A vertical graphitization furnace characterized in that, in any one of claims 12 to 13, a temperature monitoring device is provided that enables determining the temperature of the heating zone. Claim 19 A vertical graphitization furnace according to claim 18, characterized in that the temperature monitoring device is provided to enable determining the temperature at one or more of the top of the heating zone, the middle of the heating zone, the bottom of the heating zone, and the column of material of each existing process tube.

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