Graphite manufacturing method and vertical graphitization furnace

Abstract

In a method for producing graphite in a vertical graphitization furnace having at least one process chamber (22) defining a heating zone (28), a temperature of 2200°C to 3200°C, particularly 3000°C, is generated in the heating zone (28), and particulate graphitizable material (14) is fed into the process chamber (22) through an inlet (30), the graphitizable material (14) is conveyed through the heating zone (28) of the process chamber (22) where it is graphitized to form graphite, and the resulting graphite (12) is discharged from the process chamber (22) through an outlet (40). In this case, as variant A, graphitizable material (14) having particle sizes of less than 3 mm is used, and / or as variant B, a column of material (94) is formed throughout the heating zone (28) of the specific process chamber (22), and the graphitizable material (14) is fed through the inlet (30) and then flows down from above through the input zone (24) of the process chamber (22) onto the column of material (94), and / or as variant C, a specific graphitizable material (14) contained in the heating zone (28) is used. A column of material 94 is formed in a stationary heating zone 98 of the process chamber 22, and the graphitizable material 14 is fed through the inlet 30 and then flows down from above onto the column of material 94 through a drop heating zone 96, also included in the heating zone 28, and / or, as variant D, the graphitizable material 14 is contained in one or more material containers 100 and conveyed through the particular process chamber 22 and its heating zone 28. Additionally, vertical graphitization furnaces 10 are provided that are optimized specifically for variants C and D.

Description

Technical Field

[0001] The present invention relates to a method for producing graphite in a vertical graphitization furnace having at least one process chamber defining a heating zone, a) generating a temperature of 2200°C to 3200°C, particularly 2700°C to 3200°C, preferably 3000°C in the heating zone (28), b) supplying particulate graphitizable material through an inlet into the process chamber, c) transporting the graphitizable material through the heating zone of the process chamber, where it is graphitized to become graphite, d) the resulting graphite being discharged from the process chamber through an outlet.

[0002] Furthermore, the present invention relates to a vertical graphitization furnace having at least one process chamber defining a heating zone, a) equipped with a heating device capable of generating a temperature of 2200°C to 3200°C, particularly 3000°C in the heating zone, b) equipped with a loading conveyor capable of supplying particulate graphitizable material through an inlet into the process chamber, c) the graphitizable material being transported through the heating zone of the process chamber, where it is graphitized to become graphite, d) there being an unloading conveyor capable of discharging the resulting graphite from the process chamber through an outlet.

Background Art

[0003] The graphitization of graphitizable materials is carried out in an inert gas atmosphere. It is known to produce polycrystalline graphite used as a negative electrode material in a batch process of a so-called Acheson furnace that graphitizes graphitizable materials.

[0004] Furthermore, it is known from European Patent No. 2980017 (B1) to graphitize graphitizable materials having a particle size of 3 mm or more in a vertical graphitization furnace of the type described at the beginning. The graphite obtained after this process has to be ground into graphite powder because the particles are too large to be used as a negative electrode material.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a method and a vertical graphitization furnace of the type described at the beginning, which enable high energy efficiency and substantially constant and reproducible graphite quality.

Means for Solving the Problems

[0006] The above problems are solved in a method of the type described at the beginning, as a modification A, a graphitizable material having a particle size of less than 3 mm is used, and / or as a modification B, a material column is formed throughout the heating zone of a specific process chamber, and the graphitizable material supplied through the inlet flows down from above onto the material column through the charging zone of the process chamber, and / or as a modification C, a material column is formed in the stationary heating zone of a specific process chamber, where the stationary heating zone is included in the heating zone, and the graphitizable material supplied through the inlet also flows down from above onto the material column through the falling heating zone included in the heating zone, and / or as a modification D, the graphitizable material is placed in one or more material containers and conveyed through a specific process chamber and its heating zone.

[0007] According to the present invention, the above problems are solved in the method of the type described at the beginning by a plurality of measures, which can be applied alone, or in a synergistic combination, or, when using a graphitization furnace having a plurality of process chambers, applied in parallel, and it has been recognized that they contribute to a more effective process procedure compared to the prior art. Since Modifications A, B, C, and D can also be carried out in parallel, in each case of Modifications B, C, and D and where appropriate, a "specific" process chamber may be mentioned. This indicates that one specific process chamber is targeted when there are a plurality of process chambers in the furnace. This process chamber may be the process chamber in which that modification proceeds as long as another modification can proceed simultaneously, but this is not necessary. This is not possible in Modifications B and C.

[0008] According to Modification A, in the most advantageous case, it is possible to eliminate the need to grind the obtained graphite later. In any case, the labor required for sufficient grinding can be reduced.

[0009] In Modification B, a continuous process is enabled in a predetermined atmosphere.

[0010] In Modification C, a kind of preheating can be performed in the dropping heating zone, so that the energy required to heat the material column formed from a graphitizable material that has already been preheated is reduced.

[0011] In Modification D, a smaller volume is graphitized in the material container, thereby improving the process procedure.

[0012] In order to always achieve a controllable process, it is advantageous that a volume of graphitizable material per unit time equal to the volume of graphite discharged per unit time from a specific process chamber is supplied to this process chamber.

[0013] Graphitizable materials can be supplied continuously or intermittently to a specific process chamber, and graphite can be discharged continuously or intermittently from this process chamber. Continuous supply and discharge are preferred. In an intermittent process, the supply and discharge can be carried out simultaneously or with a time shift.

[0014] In order to reproducibly implement Method Variants B and C, in Variant B and / or Variant C, it is advantageous if the filling level of the material column is kept substantially constant.

[0015] For the control and monitoring of the preheating in Variant C, it may be advantageous to blow gas into the falling heating zone countercurrent or cocurrent to the falling direction of the graphitizable material.

[0016] As already described above, a graphitization furnace having a plurality of process chambers can be used, and the plurality of process chambers are operated in parallel in time.

[0017] Regarding Variant A, it is advantageous if the particles of the graphitizable material have an average particle size of more 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 if the particles of the graphitizable material have an average particle size of 5 μm to 3000 μm, 500 μm to 2000 μm, or 1000 μm to 1500 μm.

[0018] For effective operation, it is advantageous if the temperature of the heating zone is measured, in particular, at the upper end of the heating zone and / or at approximately the center of the heating zone and / or at the lower end of the heating zone and / or in the material column of each process tube present. In this way, by controlling the heating device to compensate for unwanted temperature changes, the temperature fluctuations in the heating zone can be quickly taken into account.

[0019] In a vertical graphitization furnace of the type described at the beginning, the above problems are e) In at least one process chamber, the heating zone includes a dropping heating zone and a stationary heating zone. In the stationary heating zone, a material column is formed, and the graphitizable material supplied through the inlet can flow down onto the material column from above through the dropping heating zone, and / or f) The problem is solved by the presence of a conveyor system, whereby the graphitizable material can be placed in one or more material containers and conveyed through at least one process chamber and its heating zone.

[0020] Thereby, the graphitization furnace is optimized, especially with respect to process variants C and D.

[0021] In this case, it is advantageous that the loading conveyor and the unloading conveyor are configured to convey the material containers filled with the material, and the conveyor system includes a process chamber conveyor configured to convey the material containers from the inlet to the outlet.

[0022] The vertical graphitization furnace can operate particularly effectively when the conveyor system is a circulating conveyor system and additionally includes a connecting conveyor capable of conveying the material container from the unloading conveyor to the loading conveyor.

[0023] Advantageously, the material container is a crucible having a crucible lid.

[0024] As described above, it is advantageous if the graphitization furnace has a plurality of process chambers.

[0025] Furthermore, a temperature monitoring device capable of measuring the temperature of the heating zone, especially at the upper end of the heating zone and / or near the center of the heating zone and / or at the lower end of the heating zone and / or in the material column of each existing process tube, is advantageous.

[0026] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0028] Figure 1 shows a vertical graphitization furnace 10 used for manufacturing polycrystalline graphite 12 for a negative electrode material, which will be simply referred to as furnace 10 hereinafter. As a starting material for manufacturing polycrystalline graphite 12, particulate graphitizable material 14 is used. The graphitizable material contains carbon and is converted from amorphous carbon to polycrystalline graphite during the graphitization process. Examples of graphitizable materials are lignite, bituminous coal, and in some cases, plastics.

[0029] Preferably, the particle size of the particles of the graphitizable material 14 is less than 3 mm. Preferably, the particles of the graphitizable material 14 have an average particle size of more 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. Alternatively, the particles can have an average particle size of 5 μm to 3000 μm, 500 μm to 2000 μm, or 1000 μm to 1500 μm.

[0030] The furnace 10 comprises a process tube 16 having a graphite tube wall 18, the process tube 16 accommodating a process chamber 22 in its inner chamber 20, the process chamber 22 defining an input zone 24 arranged vertically above, a discharge zone 26 arranged vertically below, and a heating zone 28 arranged therebetween where particles of graphitizable material 14 are graphitized into graphite 12.

[0031] Thereby, the upper end 28a of the heating zone 28 is defined at the transition from the input zone 24 to the heating zone 28, and correspondingly the lower end 28b of the heating zone 28 is defined at the transition from the heating zone 28 to the discharge zone 26. The inner chamber 20 or the process chamber 22 preferably has a circular cross-section. However, other cross-sections are possible, such as elliptical, square, rectangular, etc. Generally, the tube wall 18 reproduces the shape of the cross-section of the inner chamber 20 or the process chamber 22 and has a corresponding outer cross-section, which may be different from the outer cross-section of the inner chamber 20 or the process chamber 22.

[0032] The input zone 24 of the process tube 16 is connected at an inlet 30 to the outlet side 32 of a conveying conveyor 34 for the graphitizable material 14, and the graphitizable material 14 is supplied from a material reservoir 38 to its inlet side 36. In this embodiment, the conveying conveyor 34 is configured to supply the graphitizable material 14 as it is, and is particularly configured as a screw conveyor known per se for this purpose. The discharge zone 24 of the process chamber 22 is correspondingly connected at an outlet 40 to the input side 42 of a discharging conveyor 44, and the produced graphite 12 is taken out from the discharge zone 26 and discharged. In this embodiment, the discharging conveyor 44 is configured to convey the graphite 12 as it is, and for this purpose the discharging conveyor 44 is also configured as a screw conveyor. This screw conveyor is additionally cooled by a water cooling system, which is also known per se.

[0033] The loading conveyor 34 and the unloading conveyor 44 are configured to be able to form an airtight connection with the process tube 16 and to be able to perform conveyance under the exclusion of the ambient atmosphere. For this purpose, alternative conveyance concepts are also considered, such as a rotary valve, or a double flap system combined with a conveyor belt, a vibrating chute, etc.

[0034] In the region of the heating zone 28, the process chamber 16 is heated by a heating device 46 to about 2200 °C to about 3200 °C, preferably about 3000 °C, for the graphitization process, and is shown in the figure by the darkly hatched region of the process tube 16. The heating device 46 is actually an electric heating device. For this purpose, for example, the wall thickness of the process tube 16 can be reduced in the region of the heating zone 28 so that the process tube 16 is heated more effectively there due to its high electrical resistance. The heating zone 28 is defined by a continuous portion of the process chamber 22 where substantially the same graphitization temperature exists.

[0035] The process tube 16 passes through the through-opening 48 in the upper ceiling wall 50 and the through-opening 52 in the lower bottom wall 54 of the insulating housing 56 made of, for example, a steel plate, so that the process tube 16 projects upward from the insulating housing 56 at the upper end portion 16a and projects downward at the lower end portion 16b. Plate-shaped insulating elements 58, preferably made of graphite felt, are respectively arranged inside the ceiling wall 50 and the bottom wall 54, and are provided with an axially stepped through-hole 60 for the process tube 16, respectively defining a stepped region 62. Each region where the cross-section of the stepped through-hole 60 is small is directed toward the ceiling wall 50 or the bottom wall 54 of the insulating housing 56 so that the stepped regions 62 face each other. The insulating elements 58 may be integral, or may be formed by two plate-shaped elements having through-openings with different diameters so that the stepped through-hole 60 is formed as a whole.

[0036] An annular chamber 66 is formed between the process tube 16 and the protective housing 64. From the stepped region 62 of the insulating element 58 on the ceiling wall 50 to the stepped region 62 of the insulating element 58 on the bottom wall 54, a graphite protective housing 64 for the process tube 16, for example a protective tube, extends along the process tube. The annular chamber 66 is open at the top and bottom towards the through openings 48 and 52 in the ceiling wall 50 and the bottom wall 54.

[0037] An insulating annular chamber 68 defined by the protective housing 64, the insulating housing 56 and the insulating element 58 is formed radially adjacent to the protective housing 64. In this embodiment, the insulating annular chamber 68 is filled with carbon black.

[0038] The through opening 48 in the ceiling wall 50 is covered by an upper connection cap 70. In this embodiment, the upper end portion 16a of the process tube 16 extends through the upper connection cap 70 such that an upper connection annular chamber 72 is formed between the ceiling wall 50 of the insulating housing 56 and the inlet 30 of the process tube 16. This connection annular chamber 72 is fluidly connected to the annular chamber 66 through the through opening 48, the ceiling wall 50 and the through portion 60 of the upper insulating element 58.

[0039] Correspondingly, the through opening 52 in the bottom wall 54 is covered by a lower connection cap 74. In this embodiment, the lower end portion 16b of the process tube 16 extends through the lower connection cap 74 such that a lower connection annular chamber 76 is formed between the bottom wall 54 of the insulating housing 56 and the outlet 40 of the process tube 16. This connection annular chamber 76 is fluidly connected to the annular chamber 66 through the through opening 52 in the bottom wall 54 and the through portion 60 of the lower insulating element 58.

[0040] At the upper and lower transition portions between the insulating housing 56 and the connection caps 70, 74, there are respectively provided housing cooling devices 78 designed as water cooling systems known per se for protecting the housing components.

[0041] The connection annular chambers 72 and 76, the annular chamber 66, and the through portion 60 of the insulating element 58 form a gas chamber 80 which is part of the protective gas system 82.

[0042] The protective gas system 82 further includes a first protective gas supply port 84.1 in the upper connection cap 70 and a second protective gas supply port 84.2 in the lower connection cap 74, through which protective gas can be blown into the gas chamber 80.

[0043] Since the insulating element 58 is porous and permeable to gas, the protective gas diffuses from the gas chamber 80 into the insulating element 58 in a region where the cross-section of the through portion 60 is small, and further diffuses into the insulating annular chamber 68. There is a protective gas discharge port 86 on the ceiling wall 50 of the insulating housing 56 so that the protective gas can be discharged. A third protective gas supply port 84.3 is also supplementally provided on the bottom wall 54 of the insulating housing 56 so that the protective gas can be selectively supplied to the insulating annular chamber 66 as well.

[0044] The reason why protective gas is required around the process tube 16 is that the graphitization of the graphitizable material 12 is carried out in an inert gas atmosphere existing in the process chamber 22. Generally, the same gas as the inert gas is used as the protective gas so that the same type of gas exists on both sides of the tube wall 18 of the process tube 16. It is also possible to use a gas different from the protective gas and the inert gas, but in that case, the protective gas also needs to be inert. For example, argon, nitrogen, helium or a mixed gas thereof can be used as the protective gas and / or the inert gas.

[0045] To introduce an inert gas into the process chamber 22, the process tube 16 is coupled to an inert gas feed port 88 at its lower end portion 16b through which the inert gas can be blown into the process chamber 22. The upper end portion 16a of the process tube 16 is connected to an exhaust gas discharge port 90, and the gas generated during graphitization can be mixed with the inert gas and discharged from the process chamber 22. Thus, in this case, the furnace 10 is operated in a countercurrent flow in which the inert gas flows through the process chamber 22 in a direction opposite to the direction of movement of the material in the process chamber 22. Alternatively, the inert gas feed port 88 may be disposed at the upper end portion 16a of the process tube 16 and the exhaust gas discharge port 90 may be disposed at the lower end portion 16b of the process tube 16. In another modification, the inert gas feed port and the exhaust gas discharge port may be connected to the process chamber 22 at both the upper and lower portions, respectively, and graphitization can be selectively performed either by the countercurrent method or the cocurrent method by appropriately switching. In any of these cases, the exhaust gas is supplied to a thermal afterburning which is known per se.

[0046] In yet another modification, a gas supply pipe may extend downward from the inert gas feed port 88 disposed at the upper end portion 16a to just above the filling level 92 of the material column 94, and the inert gas may be blown into the process chamber 22 thereabove above the material column 94.

[0047] Note that the conveying components necessary for conveying a protective gas, an inert gas or an exhaust gas, such as a blower, a gas pump, etc., the associated piping, and the control device are not shown for simplicity, respectively.

[0048] Here, the furnace 10 is operated as follows: Before the first operation start, first, oxygen and moisture due to the air particularly present must be removed from the process chamber 22 or the process chamber atmosphere therein. For this purpose, the process chamber 22 is purged with an inert gas, and the gas chamber 80 and the insulating annular chamber 68 are also purged with an inert gas.

[0049] The heating device 46 is activated, and the graphitizable material 14 is supplied by the loading conveyor 34 to the process chamber 22 up to the filling level 92. Then, when the unloading conveyor 44 is activated, initially, the non-fully converted material is carried out from the process chamber 22 until the graphite 12 obtained in the heating zone 28 reaches the unloading conveyor 44.

[0050] In the ongoing graphitization process, the graphitizable material 14 is continuously supplied to the process chamber 22 by the loading conveyor 34, and the graphite 12 obtained therefrom is continuously removed from the process chamber 22 by the unloading conveyor 44. At this time, per unit time, for example, per minute, the volume of the graphitizable material 14 equal to the volume of the graphite 12 unloaded per minute is input, so that the filling level 92 in the process tube 92 is maintained substantially constant. In this case, the furnace 10 is continuously operated as a whole from the perspective of material balance.

[0051] In a modified example, the furnace 10 is intermittently operated as a whole from the perspective of material balance. In this case, the supply and discharge are carried out simultaneously. The graphitizable material 14 is continuously supplied to the process chamber 22 by the loading conveyor 34, and at the same time, the graphite 12 obtained therefrom is continuously removed from the process chamber 22 by the unloading conveyor 44. At this time, a material exchange operation is performed, a certain volume of graphite 12 is removed, and the corresponding volume of the graphitizable material 14 is replenished.

[0052] In any case, in the continuous furnace operation, the conveying speeds of the loading conveyor 34 and the unloading conveyor 44 are set so that the residence time of the graphitizable material 14 in the heating zone 28 at about 3000 °C is about 2 to 3 hours. In some cases, in the lower region of the heating zone 28, there may already be graphite 12 that is no longer mixed with the graphitizable material.

[0053] When the temperature of the heating zone 28 is about 2700 °C, the residence time of the graphitizable material 14 may be about 10 to 20 hours.

[0054] Figure 1 shows a process procedure in which the filling level 92 in the process tube 16 corresponds to the height level of the upper end 28a of the heating zone 28. In other words, the material column 94 extends downward from the filling level 92 and further extends through the discharge zone 26 to the outlet 40 of the process tube 16 and is formed throughout the heating zone 28. In contrast, the charging zone 24 only allows the graphitizable material 14 to pass through. After being supplied to the process chamber 22 through the inlet 30, it flows down from above onto the material column 94 through the charging zone 24 and becomes part of the material column 94. Here, the term "flow down" is understood as a general term for the material falling downward regardless of technical parameters such as the fluidity of the bulk material.

[0055] Figure 2 shows an alternative type of process procedure in which the filling level 92 is below the upper end 28a of the heating zone 28. Therefore, the material column 94 is not formed throughout the heating zone 28. Rather, a falling heating zone 96 is formed between the material column 94, i.e., the filling level 92, and the upper end 28a of the heating zone 28. The graphitizable material 14 enters from the upper charging zone 24 into the falling heating zone 94, further flows down or falls onto the material column 94 through the falling heating zone 94, and collides with the material column 94 to become part of it. Therefore, when the graphitizable material 14 is falling or falling from above downward, it passes through the falling heating zone 94.

[0056] In the process procedure described here, the falling heating zone 96 is a kind of free-falling heating zone where the graphitizable material 14 freely falls from above downward. In this case, due to the countercurrent towards the exhaust gas discharge port 90 of the atmosphere in the process tube 16, the fall of the particles of the graphitizable material 14 can be retarded compared to free fall, and the residence time in the falling heating zone 96 can be lengthened. In the aforementioned modification where the exhaust gas discharge port 90 is provided at the bottom of the process tube 16, the gas flow can result in accelerating the fall of the particles of the graphitizable material compared to free fall, and the residence time in the falling heating zone 96 can be shortened.

[0057] In a modification not particularly shown, in order to selectively adjust the residence time in the dropping heating zone 96, and thereby selectively slow down or accelerate the dropping speed of the particles of the graphitizable material 14, an inert gas can be blown into the dropping heating zone 96 countercurrently or cocurrently with respect to the dropping direction, as necessary.

[0058] Among the heating zone 28, the portion where the material column 94 is formed defines a stationary heating zone 98 included in the heating zone 28. The term "stationary" is intended to mean that although the material column 94 itself exists in a substantially stationary state, the material column 94 changes due to material supply and material removal during the operation of the furnace 10. The dropping heating zone 94 and the stationary heating zone 98 are at least substantially equal in temperature.

[0059] In the dropping heating zone 94, the graphitizable material 14 is already heated while flowing down, and reaches the material column 94 at an initial temperature that is already higher than the case of the material column 94 having a filling level 92 at the upper end 28a of the heating zone 28. As a result, the material particles of the graphitizable material 14 reach the temperature required for graphitization more rapidly.

[0060] In the modification shown in FIG. 2, the dropping heating zone 96 and the stationary heating zone 98 each occupy about 50% of the heating zone 28. In fact, effective graphitization can be achieved in a furnace 10 in which the dropping heating zone 96 occupies 10% - 60%, preferably 20% - 55%, more preferably 30% - 50%, particularly 30%, or 50% as shown in the figure, of the heating zone 28.

[0061] FIG. 3 shows a furnace 10 according to a second embodiment in which two process tubes 16.1 and 16.2 extend through an insulating housing 56. This embodiment also exemplifies another modification in which there are more than two process tubes 56 and they extend through the insulating housing 56 in a corresponding manner.

[0062] In FIG. 3, for the sake of simplicity, not all parts and components are labeled with reference signs. The identified parts and components corresponding to the parts and components in FIGS. 1 and 2 are labeled with the same reference signs. Whether it belongs to the first process tube 16.1 or the second process tube 16.2 is sometimes identified by the index.1 or.2.

[0063] Here, the protective housing 64 surrounds both process tubes 16.1 and 16.2, but it is also possible to assign separate protective housings 64 to each of the process tubes 16.1 and 16.2.

[0064] Furthermore, FIG. 3 shows that the process tubes 16.1 and 16.2 are adjacent to each other. However, as shown in FIG. 4, in a variant, the process tubes 16.1 and 16.2 may be spaced apart from each other, and carbon black is also arranged between the process tube 16.1 and the process tube 16.2, and the annular chamber 68 is deformed accordingly. Correspondingly, the surrounding housing and related through-holes and openings are also changed. As a result, there are two protective housings 64 and an annular chamber 66, and similarly, there are two upper connection caps 70 and two lower connection caps 74, but not all components that appear twice in the figure have reference signs respectively.

[0065] In the example shown in FIG. 3, a separate loading conveyor 34.1 or 34.2 and a separate unloading conveyor 44.1 or 44.2 are assigned to each of the process tubes 16.1 and 16.2. In a variant, there can also be only a single loading conveyor 34 that supplies materials to both process tubes 16.1 and 16.2. Therefore, there can also be only a single unloading conveyor 44 that receives and unloads graphite 12 from both process tubes 16.1 and 16.2.

[0066] If there are more than two process tubes 16, a single inlet conveyor 34 can supply the graphitizable material 14 to only one process tube 16, a pair of process tubes 16, or a group of three or more process tubes 16, and possibly all process tubes 16. Similarly, if there are more than two process tubes 16, a single outlet conveyor 44 can receive and discharge the obtained graphite 12 from only one process tube 16, a pair of process tubes 16, or a group of three or more process tubes 16, and possibly all process tubes 16.

[0067] If separate inlet conveyors 34.1, 34.2 and separate outlet conveyors 44.1, 44.2 are assigned to two process tubes 16.1, 16.2 respectively, different graphitizable materials 14 that require different residence times in their respective heating zones 28.1, 28.2 or stationary heating zone 98 can be supplied to the process tubes 16.1, 16.2. For the stationary heating zone 98, in FIG. 3, only the stationary heating zone 98.2 in the process tube 16.2 is shown. This indicates that the different process tubes 16.1, 16.2 can also be operated in different modes.

[0068] Regardless of the total number of process tubes 16, the heating zones 28.1, 28.2 may be of the same length or different lengths for two different process tubes 16.1, 16.2. If the process tubes 16.1, 16.2 are each operated with a falling heating zone 96 present, the ratio of their lengths, and thus the respective length ratios of the falling heating zone 96 and the stationary heating zone 98, can also be different.

[0069] FIG. 5 shows a third embodiment of the furnace 10, in which the graphitizable material 14 is not introduced directly into the process chamber 22 as a bulk material or a flowing material, but is placed in a material container 100 and conveyed through the process chamber 22 and the heating zone 28. The material container 100, which is labeled with only three reference numerals, is provided as a crucible 102 having a crucible lid 104 in this embodiment. The conveyor system 106 is configured such that the material container 100 filled with the graphitizable material 14 is conveyed into the process chamber 22 as it passes through the inlet 30, passes through the process chamber 22 and heads towards the outlet 40, and can exit the process chamber 22 as it passes through the outlet 40.

[0070] For this purpose, the conveyor system 106 includes, in this embodiment, a loading conveyor 34 and an unloading conveyor 44 configured to convey the material container 100 filled with the material. Further, the conveyor system 106 includes a process chamber conveyor 108 configured to convey the material container 100 filled with the material even within the process chamber 22, and conveys the material container 100 from the inlet 30 to the outlet 40.

[0071] Furthermore, in this embodiment, the conveyor system 106 is designed as a circulating conveyor system and includes, for this purpose, a connecting conveyor 110 capable of conveying the material container 100 from the unloading conveyor 44 to the loading conveyor 34.

[0072] Here, the loading conveyor 34 and the unloading conveyor 44 are each designed as rotary conveyors 112 and 114, and each has a rotary element 116 or 118 that is rotatable about its respective vertical rotation axis 120. The process chamber conveyor 108 and the connecting conveyor 110 are designed as linear conveyors 122 or 124, and for this purpose, in each case, there is a pushing device 126 having a driving push element 128 in the form of a push rod. In the case of the process chamber conveyor 108, after the material container 100 enters the process chamber 22 at the loading zone 24, the push element 128 pushes the material container 100. The material container 100 abuts against the material container 100 below it, whereby all the material containers 100 in the process chamber 22 are advanced by one. For this to function, there is a space at the outlet 40 of the process chamber 22 where there is no material container 100 at this point.

[0073] When the material container 100 passes through the heating zone 28 during the process of passing through the process chamber 22, the graphitizable material 14 is graphitized to become graphite 12. As a result, the material container 100 at the outlet 40 contains graphite 12. Since there is a space formed at the inlet 30 when the material container 100 reaches the outlet 40 of the process tube 16, the material container 100 loaded with the graphitizable material 14 can be conveyed into the process chamber 22 by the loading conveyor 34. At this time, a space is created in the loading conveyor 34 at the end of the conveying section of the connecting conveyor 110, and an empty material container 100 is pushed into it by the connecting conveyor 110 that operates in the same manner as the process chamber conveyor 108. Next, when the unloading conveyor 44 takes out the material container 100 loaded with graphite 12 from the process tube 16, the space created at the inlet of the connecting conveyor 110 is filled with an empty material container 100 by the unloading conveyor 44.

[0074] The loading conveyor 34 is provided with a filling station 130 that can fill an empty material container 100 with the graphitizable material 14. The unloading conveyor 44 is provided with a discharging station 132 that can take out the graphite 12 from the material container 100. An appropriate airlock design is realized so that the furnace atmosphere is not contaminated by the outside air.

[0075] In the situation shown in FIG. 5, the rotating elements 116 and 118 are designed to accommodate four material containers 100, and a 90° rotation is performed about the rotation axis 120 in each cycle. In this case, at the filling station 130, an empty material container 100 arrives one cycle before the inlet 30 of the process tube 16, and at the unloading station 132, a material container 100 filled with graphite 12 arrives one cycle after the outlet 40 of the process tube 16.

[0076] Therefore, in the furnace 10 described above, the material containers 100 intermittently convey the process chamber 22. In a conveyor system 106 designed for this purpose as a modification, the material containers 100 can also be continuously conveyed within the process chamber 22.

[0077] In all of the above-described embodiments, the temperature in the heating zone 28 or the temperature of the material column 94 is monitored by a temperature monitoring device.

[0078] For this purpose, the temperature is measured at the upper end 28a of the heating zone 28 and / or approximately in the center of the heating zone 28 and / or the lower end 28b of the heating zone 28 of each existing process tube 16.

[0079] Alternatively or additionally, the temperature measurement can also be performed above the filling level 92 of the material column 94.

[0080] The temperature measurement is preferably performed with a pyrometer equipped with a pyrometer tube known per se, and the measurement ends of the pyrometer tubes are arranged at the respective measurement locations. The measurement is preferably performed near the heating device 46.

[0081] For measurement in the heating zone 28, the pyrometer tube extends, for example, from the outside through the outer wall of the insulating housing 56, through the insulating annular chamber 66, and further through the wall of the protective housing 64 up to the front of the tube wall 18 of the process tube 16 in the annular chamber 66. The associated pyrometer is arranged at the free end of the pyrometer tube outside the protective housing 56. The corresponding pyrometer tube is preferably arranged horizontally. In this way, the temperature can be determined from the temperature measured outside the process tube.

[0082] When measuring above the filling level 92 of the material column 94, the pyrometer tube extends from above to just above the filling level 92 in the process tube 16. In this case, the pyrometer tube preferably extends vertically, and the pyrometer is correspondingly arranged at the upper part of the pyrometer tube. However, it is also possible to arrange the pyrometer tube horizontally. However, also in this case, the pyrometer tube penetrates the tube wall 18 of the process tube 16 and leads into the process chamber 22. Some embodiments of the invention related to the present invention are shown below. [Embodiment 1] A method for producing graphite in a vertical graphitization furnace having at least one process chamber (22) defining a heating zone (28), a) generating a temperature in the heating zone (28) of 2200 °C to 3200 °C, particularly 2700 °C to 3200 °C, preferably 3000 °C, b) a particulate graphitizable material (14) is fed into the process chamber (22) through an inlet (30), c) the graphitizable material (14) is conveyed through the heating zone (28) of the process chamber (22), where it is graphitized to become graphite, d) the resulting graphite (12) is discharged from the process chamber (22) through an outlet (40), in the method for producing graphite, As a variant A, a graphitizable material (14) with a particle size of less than 3 mm is used, and / or As a variant B, a material column (94) is formed throughout the heating zone (28) of a specific process chamber (22), and the graphitizable material (14) fed through the inlet (30) flows down from above onto the material column (94) through the charging zone (24) of the process chamber (22), and / or As a variant C, a material column (94) is formed in a stationary heating zone (98) of a specific process chamber (22), where the stationary heating zone (98) is included in the heating zone (28), and the graphitizable material (14) fed through the inlet (30) also flows down from above onto the material column (94) through a falling heating zone (96) included in the heating zone (28), and / or As a variant D, the graphitizable material (14) is placed in one or more material containers (100) and conveyed through a specific process chamber (22) and its heating zone (28), characterized in that, a method for producing graphite. [Embodiment 2] A graphitizable material (14) having a volume per unit time equal to the volume of graphite (12) discharged per unit time from a specific process chamber (22) is fed into this process chamber (22), characterized in that, the method according to Embodiment 1. [Embodiment 3] The graphitizable material (14) is fed continuously or intermittently into a specific process chamber (22), and the graphite (12) is discharged continuously or intermittently from this process chamber (22), characterized in that, the method according to Embodiment 1 or 2. [Embodiment 4] The method according to any one of Embodiments 1 to 3, characterized in that, in Modification Example B and / or Modification Example C, the filling level (92) of the material column (94) is kept substantially constant. [Embodiment 5] The method according to any one of Embodiments 1 to 4, characterized in that, in Modification Example C, gas is blown into the drop heating zone (96) countercurrently or cocurrently with respect to the dropping direction of the graphitizable material (14). [Embodiment 6] The method according to any one of Embodiments 1 to 5, characterized in that a graphitization furnace (10) having a plurality of process chambers (22) is used, and the plurality of process chambers (22) are operated in parallel in time. [Embodiment 7] The method according to any one of Embodiments 1 to 6, characterized in that the particles of the graphitizable material (14) have an average particle size of more 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 (14) have an average particle size of 5 μm to 3000 μm, 500 μm to 2000 μm, or 1000 μm to 1500 μm. [Embodiment 8] The method according to any one of Embodiments 1 to 7, characterized in that the temperature of the heating zone (28) is measured, in particular, at the upper end (28a) of the heating zone (28) and / or at the approximate center of the heating zone (28) and / or at the lower end (28b) of the heating zone (28) and / or in the material column (94) of each existing process pipe (16). [Embodiment 9] A vertical graphitization furnace having at least one process chamber (22) defining a heating zone (28), a) a heating device (46) capable of generating a temperature of 2200°C to 3200°C, in particular 3000°C, in the heating zone (28); b) a loading conveyor (34) capable of supplying particulate graphitizable material (14) into the process chamber (22) through an inlet (30); comprising c) the graphitizable material (14) is conveyed through the heating zone (28) of the process chamber (22) and is graphitized therein to become graphite; d) there is an unloading conveyor capable of discharging the obtained graphite (12) from the process chamber (22) through an outlet (40). e) The heating zone (28) in at least one process chamber (22) includes a dropping heating zone (96) and a stationary heating zone (98), and in the stationary heating zone (98), a material column (94) is formed, and the graphitizable material (14) supplied through the inlet (30) is configured to flow down from above onto the material column (94) through the dropping heating zone (96), and / or f) There is a conveyor system (106), whereby the graphitizable material (14) can be placed in one or more material containers (100) and conveyed through at least one process chamber (22) and its heating zone (28), characterized by a vertical graphitization furnace. [Embodiment 10] The loading conveyor (34) and the unloading conveyor (44) are configured to convey the material container (100) containing the material, and the conveyor system (106) includes a process chamber conveyor (108) configured to convey the material container (100) from the inlet (30) to the outlet (40), characterized by the vertical graphitization furnace according to Embodiment 9. [Embodiment 11] The conveyor system (106) is a circulating conveyor system and includes a connecting conveyor (110) configured to convey the material container (100) from the unloading conveyor (44) to the loading conveyor (34), characterized by the vertical graphitization furnace according to Embodiment 10. [Embodiment 12] The material container (100) is a crucible (102) having a crucible lid (104), characterized by the vertical graphitization furnace according to any one of Embodiments 9 to 11. [Embodiment 13] There are a plurality of process chambers (22), characterized by the vertical graphitization furnace according to any one of Embodiments 9 to 12. [Embodiment 14] A temperature monitoring device is provided that can measure the temperature of the heating zone (28), particularly at the upper end (28a) of the heating zone (28) and / or approximately in the middle of the heating zone (28) and / or at the lower end (28b) of the heating zone (28) and / or in the material column (94) of each process pipe (16) present, characterized by the vertical graphitization furnace according to any one of Embodiments 9 to 13.

Claims

1. A method for producing graphite in a vertical graphitization furnace having at least one process chamber (22) defining a heating zone (28), comprising: a) generating a temperature in the heating zone (28) of 2200 °C to 3200 °C, in particular 2700 °C to 3200 °C, preferably 3000 °C; b) a particulate graphitizable material (14) is fed through an inlet (30) into the process chamber (22); c) the graphitizable material (14) is conveyed through the heating zone (28) of the process chamber (22), where it is graphitized to form graphite; d) the resulting graphite (12) is discharged from the process chamber (22) through an outlet (40); In a method for producing graphite, the process chamber (22) is housed in the inner chamber (20) of a process tube (16) having a graphite outer tube wall (18), and the process tube (16) is heated by an electrical heating device based on the electrical resistance of the process tube (16) in the region of the heating zone (28); e) As Variant A, a graphitizable material (14) with a particle size of less than 3 mm is used, and / or fa) As Variant B, a material column (94) is formed throughout the heating zone (28) of a specific process chamber (22), and the graphitizable material (14) fed through the inlet (30) flows down from above onto the material column (94) through the input zone (24) of the process chamber (22), and / or fb) As Variant C, a material column (94) is formed in a stationary heating zone (98) of a specific process chamber (22), where the stationary heating zone (98) is included in the heating zone (28), and the graphitizable material (14) fed through the inlet (30) similarly flows down from above onto the material column (94) through a falling heating zone (96) included in the heating zone (28), and / or g) As Variant D, the graphitizable material (14) is placed in one or more material containers (100) and conveyed through a specific process chamber (22) and its heating zone (28); A method for producing graphite, characterized in that.

2. A graphitizable material (14) having a volume per unit time equal to the volume per unit time of graphite (12) discharged from a specific process chamber (22) is fed into this process chamber (22), according to the method of Claim 1.

3. The method according to claim 1 or 2, characterized in that a graphitizable material (14) is continuously or intermittently supplied to a specific process chamber (22), and graphite (12) is continuously or intermittently discharged from this process chamber (22).

4. The method according to any one of claims 1 to 3, characterized in that in Modification B and / or Modification C, the filling level (92) of the material columnar body (94) is kept substantially constant.

5. The method according to any one of claims 1 to 4, characterized in that in Modification C, gas is blown into the dropping heating zone (96) countercurrently or cocurrently with respect to the dropping direction of the graphitizable material (14).

6. The method according to any one of claims 1 to 5, characterized in that a graphitization furnace (10) having a plurality of process chambers (22), in which the plurality of process chambers (22) are operated in parallel in time, is used.

7. The method according to any one of claims 1 to 6, characterized in that the particles of the graphitizable material (14) have an average particle size of more 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 (14) have an average particle size of 5 μm to 3000 μm, 500 μm to 2000 μm, or 1000 μm to 1500 μm.

8. The method according to any one of claims 1 to 7, characterized in that the temperature of the heating zone (28) is measured in particular at the upper end (28a) of the heating zone (28) and / or at approximately the center of the heating zone (28) and / or at the lower end (28b) of the heating zone (28) and / or in the material columnar body (94) of each existing process pipe (16).

9. A vertical graphitization furnace having at least one process chamber (22) defining a heating zone (28), a) a heating device (46) capable of generating a temperature of 2200 °C to 3200 °C, in particular 3000 °C, in the heating zone (28); b) a loading conveyor (34) capable of supplying particulate graphitizable material (14) to the process chamber (22) through an inlet (30); comprising: c) the graphitizable material (14) is conveyed through the heating zone (28) of the process chamber (22), where it is graphitized into graphite; d) There is a carry-out conveyor capable of discharging the obtained graphite (12) from the process chamber (22) through the outlet (40). e) The process chamber (22) is accommodated in the inner chamber (20) of a process tube (16) having a graphite outer tube wall (18), and the process tube (16) is heated by an electric heating device based on the electrical resistance of the process tube (16) in the region of the heating zone (28). The heating zone (28) in at least one process chamber (22) includes a dropping heating zone (96) and a stationary heating zone (98). In the stationary heating zone (98), a material column (94) is formed, and the graphitizable material (14) supplied through the inlet (30) is configured to flow down onto the material column (94) from above through the dropping heating zone (96), and / or f) There is a conveyor system (106), whereby the graphitizable material (14) can be placed in one or more material containers (100) and conveyed through at least one process chamber (22) and its heating zone (28). A vertical graphitization furnace characterized by this.

10. The loading conveyor (34) and the unloading conveyor (44) are configured to convey a material container (100) containing material, and the conveyor system (106) includes a process chamber conveyor (108) configured to convey the material container (100) from the inlet (30) to the outlet (40). The vertical graphitization furnace according to claim 9, characterized by this.

11. The conveyor system (106) is a circulating conveyor system and includes a connection conveyor (110) capable of conveying the material container (100) from the unloading conveyor (44) to the loading conveyor (34). The vertical graphitization furnace according to claim 10, characterized by this.

12. The material container (100) is a crucible (102) having a crucible lid (104). The vertical graphitization furnace according to any one of claims 9 to 11, characterized by this.

13. There are a plurality of process chambers (22). The vertical graphitization furnace according to any one of claims 9 to 12, characterized by this.

14. There is a temperature monitoring device that can measure the temperature of the heating zone (28), particularly at the upper end (28a) and / or approximately in the center and / or at the lower end (28b) of the heating zone (28) and / or in the material column (94) of each existing process pipe (16). The vertical graphitization furnace according to any one of claims 9 to 13 is characterized by this.

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