JP6320023B2 - Graphite powder production apparatus and method - Google Patents

Description

  The present invention relates to a graphite powder manufacturing apparatus and method for graphitizing carbon powder as a material.

  Graphite powder has excellent thermal conductivity, conductivity, heat resistance, chemical resistance, etc., so it is used as a filler material to improve the properties of composite materials such as carbonaceous refractories, ceramic materials, and resins. The In recent years, it has been widely used as a negative electrode material for lithium ion secondary batteries because of its crystallinity and electrochemical stability, and it is expected that the demand for graphite powder will increase further in the future. ing.

  Graphite is roughly classified into natural graphite and artificial graphite produced industrially. Artificial graphite is a graphitized carbon with a three-dimensional ordered structure of graphite by applying a graphitization treatment that heats amorphous carbon at a high temperature of 2000 ° C or higher. It is. As a method for obtaining graphite powder industrially, carbon powder is filled into a heat-resistant container such as a graphite crucible, and the container is loaded into a furnace of the Atchison furnace type and graphitized at a temperature of 2500 to 3000 ° C. by a batch method. (For example, Patent Document 1 and Patent Document 2). Hereinafter, the conventional batch method will be described with reference to FIG.

  As shown in FIG. 3, the Atchison furnace 13 is a furnace as large as a swimming pool made of refractory bricks, and electrodes 14 are arranged at both ends of the furnace. The furnace is filled with a filler 15 called packing coke without gaps, and a plurality of rectangular parallelepiped boxes 16 filled with carbon powder are arranged so as to be buried in the filler 15. When the electrode 14 is energized, the filler 15 generates heat due to Joule heat, and the carbon powder in the box 16 indirectly receives heat from the filler 15, thereby graphitizing the carbon powder to produce graphite powder.

  On the other hand, as a method for obtaining graphite powder by a continuous method, a method is used in which a cylindrical heating element is energized to generate heat, and the carbon powder passing through the cylinder is heat-treated by radiant heat transfer from the cylindrical heating element. There is a method in which a plurality of pairs of electrodes are formed in the chemical furnace, the electrodes are energized to generate heat, and a heat treatment is performed by passing an object to be heat-treated through the inside of the electrodes.

Japanese Patent No. 4666676 JP-A-11-236205

  However, the following problems have been pointed out in the prior art. That is, since the Atchison furnace 13 is a batch method, there are problems such as a long manufacturing cycle, high power cost, generation of variation in processing temperature depending on the furnace filling position, and low productivity.

  In the Atchison furnace 13, the carbon powder is packed in a box 16, and after the box 16 is placed in the furnace, the filler is filled so as to embed the box 16, and finally the box 16 is filled into the filler 15. We are working to fill. These operations were very inefficient. Moreover, in these series of operations, the working environment is poor due to, for example, the carbon powder soaring, and there are significant problems in terms of workability.

  On the other hand, in the continuous method, the temperature of the carbon powder is likely to be non-uniform because the heat conductivity is poor, and because the powder is a powder, a static layer is likely to be generated in the furnace. In addition, it has been difficult in practice to carry out highly efficient and long-term continuous operation because the generated gas tends to cause clogging problems due to the condensation and deposition of powder during the heat treatment process.

  The present invention has been made to solve the above problems, and even if a continuous direct energization method is used for a long time instead of a batch indirect energization method, carbon powder is blocked in the furnace. It is an object of the present invention to provide a graphite powder manufacturing apparatus and method capable of continuing the heat treatment without increasing the productivity and workability.

In order to achieve the above object, an apparatus for producing graphite powder according to the present invention includes the following components (a) to ( f ).
(A) A composite part in which a liquid binder is added to a mixture obtained by mixing carbon powder as a raw material and a solid binder and combined to produce a composite.
(B) A granulated portion in which the composite is a granulated coal having a diameter of 4 mm or more .
(C) A curing treatment part for heat-curing the granulated coal before heat treatment .
(D) A heat treatment part for heat-treating the dried granulated coal.
(E) A powder generating part that crushes the graphitized granulated charcoal into graphite powder.
(F) The curing temperature at which the curing treatment unit heat-cures the granulated coal is less than 170 ° C.

Moreover, it is preferable that the said solid binder is 3 weight% or more and less than 10 weight%. Further, the diameter of the granulated charcoal, more preferably more than 10 mm. Furthermore, it is preferable that the granulated charcoal has a cylindrical shape with a smooth surface and a uniform shape and size. The present invention is also an embodiment of a method for producing graphite powder using the above production apparatus.

  According to the present invention, carbon powder and a binder are mixed, combined, and granulated to produce granulated coal that is less likely to block during heat treatment, and then the granulated coal is heat treated and graphitized. The graphite powder can be continuously obtained by crushing the finally graphitized granulated charcoal, thereby improving the productivity and workability of the graphite powder.

The block diagram which shows the manufacturing apparatus of the graphite powder of 1st Embodiment which concerns on this invention, and its processing process. The lineblock diagram of the heat treatment part and cooling part of a 1st embodiment. The top view of the conventional Atchison furnace.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
(1) First Embodiment [Configuration]
As shown in FIG. 1, the graphite powder manufacturing apparatus according to the first embodiment includes a combination unit 1, a granulating unit 2, a curing processing unit 3, a heat treatment unit 4, a cooling unit 5, a powder generation unit 6, and an inspection. Part 7 is provided. Further, in the graphite powder manufacturing apparatus, a raw material tank 8 and a pulverizing unit 9 are provided adjacent to the combining unit 1.

  The raw material tank 8 contains the raw material M. The crushing unit 9 is a device that receives the raw material M from the raw material tank 8 and crushes the raw material M into the carbon powder A, such as a ball mill, jet mill, hammer mill, turbo mill, or the like. A raw material supply pipe 11 is attached to the lower part of the pulverization unit 9, and the carbon powder A is supplied to the combination part 1 through the raw material supply pipe 11.

[Combined part]
The combination unit 1 is composed of a combination machine such as a double-arm batch kneader. A kneader 10 for taking in carbon powder A as a raw material, binders B1 and B2, and water or hot water B3 is provided. Above the kneader 10, a raw material supply pipe 11 for supplying the carbon powder A from the pulverizing unit 9, a binder supply pipe 12a for supplying the binder B1 and the binder B2, and a water supply pipe 12b for supplying water or hot water B3 are installed. Has been. Binder B1 is a solid binder, and as a type, there is starch powder, and α corn starch powder is particularly suitable. The binder B2 is a liquid binder, such as a PVA solution.

[Granulation part]
The granulation unit 2 is composed of a granulator such as a disk pelleter. The disk pelleter is a predetermined shape using the compound C as a raw material by pressing the compound C, which is the material of the granule, with a rotating roller, pressing it into the disk, and extruding it from a hole opened in the disk. And the granulated coal D which has a magnitude | size is produced | generated. Here, the granulated coal D has a cylindrical shape with a smooth surface, and its shape and size are uniform.

[Curing processing part]
Although the hardening process part 3 is shown with the simple block in FIG. 1, it is comprised from a conveyor type continuous dryer, for example. The dryer includes a blower that blows hot air, an electric heater, and the like. When the binder B1 is starch and the binder B2 is a PVA solution, the processing temperature in the curing processing unit 3 is less than 170 ° C.

[Heat treatment part]
The heat treatment part 4 is a main part of the present embodiment, and will be described with reference to the enlarged view of FIG. The heat treatment part 4 is a part that takes in the hardened granulated coal D, heat-treats it, and graphitizes it. The heat treatment section 4 is a vertical continuous heat treatment furnace of a direct current heating method, and is directly energized to the granulated coal D put into the furnace, and generates heat by its resistance heat generation (Joule heat).

  As shown in FIG. 2, the heat treatment part 4 is provided with a furnace body heat insulation part 4c. A columnar upper electrode 4a is attached to the upper part of the furnace body heat insulating part 4c, and a cylindrical lower electrode 4b is attached to the lower part of the furnace body heat insulating part 4c. Either carbonaceous or graphite can be used for the electrode, but an artificial graphite electrode is preferably used. The flowing current may be either alternating current or direct current, and in the case of direct current, the polarity of the upper electrode and the lower electrode may be either as long as it is positive and negative. A region sandwiched between the lower end portion of the upper electrode 4a and the upper end portion of the lower electrode 4b is a heat generating zone 4d.

  In the furnace heat insulating part 4c, a charging part 4e for charging the granulated coal D is installed above the heat generating zone 4d. By passing through the heat generating zone 4d, the granulated coal D becomes graphitized granulated coal D1. A discharge portion 4f of the graphitized granulated coal D1 is formed by the cylindrical portion of the lower electrode 4b. The diameter of the input portion 4e is larger than the diameter of the discharge portion 4f. For example, the tube inner diameter of the input portion 4e is set to 1 to 2 times the tube inner diameter of the lower electrode 4b, preferably 1.5 times or less. .

  The heat treatment portion 4 is a hollow portion having a slope or a step so that the diameter gradually matches the diameter of the lower electrode from the charging portion 4e to the cylindrical portion of the lower electrode 4b. Further, a gas blowing hole 4g is formed through the upper electrode 4a in the longitudinal direction (vertical direction in FIG. 2). The gas blowing hole 4g is configured to blow an inert gas such as argon gas or nitrogen gas into the furnace of the heat treatment unit 4 from here.

[Cooling section]
As shown in FIG. 2, the cooling unit 5 includes a cylindrical water-cooling jacket 5a, a hood portion 5d attached to the lower portion of the water-cooling jacket 5a, and a water-cooling board 5b housed in the hood portion 5d. . The water cooling jacket 5 a is attached to the lower part of the lower electrode 4 b of the heating unit 4. That is, the water cooling jacket 5 a is connected to the lower part of the heat treatment unit 4. The hood portion 5d is formed in a disk shape on the upper side and a funnel shape on the lower side, and is configured to discharge the graphitized granulated coal D1 from a small-diameter opening 5e provided in the lower portion.

  Further, a gas blowing hole 5c is provided in the vicinity of the upper end portion of the water cooling jacket 5a. The gas blowing hole 5c is configured to supply an inert gas such as argon gas or nitrogen gas into the furnace of the heat treatment unit 4 through the discharge unit 4f. The water cooling board 5b is installed below the water cooling jacket 5a. The diameter of the water cooling board 5b is set larger than the diameter of the water cooling jacket 5a. The water cooling jacket 5a and the water cooling board 5b are provided with pipes (not shown) through which cooling water flows. A rotating blade (not shown) is installed on the water cooling board 5b, and the graphitized granulated coal D1 is quantitatively discharged.

[Powder generator]
The powder production | generation part 6 is arrange | positioned at the back of the cooling part 5 (illustrated in FIG. 1). The powder production | generation part 6 is a part which crushes the graphitized granulated coal D1, and produces | generates the graphite powder E, Comprising: For example, a turbo mill (made by Freund Turbo) etc. are used. In addition, the crushing said here refers to operation which isolate | separates the granulated charcoal which couple | bonded the particle | grains severally, and returns to the magnitude | size of one particle | grain, ie, one particle | grain, by dividing into a plurality. On the other hand, pulverization refers to an operation of breaking one powdery particle into a plurality of particles, that is, an operation of further reducing one particle.

[Inspection unit]
The inspection unit 7 is provided with an X-ray measuring device. The X-ray measuring instrument measures the graphitization degree of the graphite powder E, such as the interlayer distance d002, the crystallite size Lc, and La.

[Production method]
In the first embodiment, graphite powder is manufactured as follows using the above graphite powder manufacturing apparatus.
[Raw material crushing process]
The crushing unit 9 performs a raw material crushing process. In the raw material pulverization step, the pulverization unit 9 takes in the raw material M from the raw material tank 8 and crushes it into the carbon powder A. As a kind of the raw material M, for example, anthracite, calcine coal coke, calcine petroleum coke and a mixture thereof, coal coke, and raw coke of petroleum coke are used.

  The average particle size of the carbon powder A can be arbitrarily set, for example, in the range of 7 μm to 74 μm for the fine powder variety and in the range of 74 μm to 1000 μm for the powder variety. Examples of the particle size distribution of the carbon powder A include d10: 4 μm, d50: 7 μm, and d90: 12 μm.

[Composite process]
The combination part 1 performs a combination process. In the compounding step, carbon powder A from the raw material supply unit 11 and α corn starch as the binder B1 from the binder supply pipe 12a are introduced into the kneader 10 and mixed together for 5 minutes. The mixing ratio of carbon powder A and α corn starch is such that carbon powder A is 100 and α corn starch is in the range of 3 to 10. A mixture of carbon powder A and α corn starch is called mixed powder. There is no particular limitation on the mixing method, and the mixing time may be set to a time during which the carbon powder A and the binder B1 are sufficiently kneaded.

  The mixed powder is mixed with a kneader 10 by adding a 10% PVA solution as a binder B2 from the binder supply pipe 12a and water or hot water B3 from the water supply pipe 12b, and kneading the mixture with a kneader 20. Do for a minute. There is no particular limitation on the mixing method, and the mixing time may be set to a time during which the mixed powder and the binder B2 are sufficiently kneaded. At this time, the mixing ratio of the mixed aggregate, the 10% PVA solution and the water is 5 to 20 for the PVA 10% solution and 5 to 20 for the water when the carbon powder A is 100.

  In order to obtain a good granulated coal D in the granulating part 2, the binder B1 and the binder B2 must be mixed well with the carbon powder A so that it can be granulated with an appropriate pressure. Moreover, since a certain amount of strength is required when the heat treatment in the heat treatment section 4 is performed, the binder B1 and the binder B2 are also required to function as a binder.

  For this reason, if the amount of the binder including the binder B1 and the binder B2 is too small, bonding and granulation are insufficient, and if it is excessive, the shape of the granulated coal is distorted, and the granulated coal adheres before drying. As a result, it becomes a granulated coal that is not suitable for being charged into the heat treatment section. On the other hand, if the amount of the binder is excessive, the yield decreases when the powder is finally returned to a powder form.

  The optimum amount of the binder B1 and the binder B2 is determined by the properties of the raw material carbon powder A and the binder B1 and binder B2, but the α corn starch which is the binder B1 A suitable range is 3% by weight or more and less than 10% by weight. Regarding the PVA 10% solution as the binder B2, when the above-mentioned carbon powder A is defined as 100, the appropriate amount is within the range of 5% by weight or more and less than 20% by weight when the PVA 10% solution is divided. The composite C produced in this way is sent out to the granulation unit 2.

[Granulation process]
The granulation part 2 performs a granulation process. In the granulation step, granulated coal D having a predetermined shape and size is generated using composite C as a material. The granulated coal D has a cylindrical shape, a granulated particle diameter of about 10 mm, and a length in the range of 10 to 15 mm. The granulated coal D is sent to the curing processing unit 3.

[Curing process]
The curing processing unit 3 performs a curing process. In the curing step, the granulated coal D is continuously dried at less than 170 ° C., and the cured granulated coal D is sent to the heat treatment unit 4. When binder B1 is starch, if it is 100 degreeC or more, starch will be hardened and it can be set as the granulated coal D suitable for throwing into the heat processing part 4. FIG. The reason why the drying temperature is set to less than 170 ° C. in the curing processing unit 3 is that when the binder B1 is starch, the starch may burn if the drying temperature is 170 ° C. or higher.

[Heat treatment process]
The heat treatment unit 4 performs heat treatment. In the heat treatment step, when the hardened granulated coal D is charged into the charging unit 4e, the granulated coal D is sequentially flowed into the heat generating zone 4d by its own weight and subjected to heat treatment. The charging speed of the granulated coal D is made to correspond to the controlled discharge speed mentioned later. Since the weight of the granulated coal D is reduced due to the volatilization of the binder component and the component contained in the carbon powder A during the heat treatment process, the charging speed becomes faster than the discharging speed. Accordingly, the conveying and charging equipment for the granulated coal D only needs to have a capacity of at least 50 to 250 kg / h.

  The heat treatment part 4 of the present embodiment directly heats the input material and raises the temperature. However, the granulated coal D just cured is poor in conductivity, and the heat treatment part is heated only by the granulated coal D. There are cases where there is a lot of waste in terms of time and power. Therefore, before the granulated coal D is charged into the charging unit 4e, a conductive material, for example, a 10mm to 20mm calcine petroleum coke lump or the like is charged into the heat treatment unit 4 in advance to fill the furnace, and the current is passed through. It is desirable to raise the heating zone 4d of the part 4 to a desired graphitization temperature.

  That is, the charging section 4e is set to about 1000 ° C. by filling the furnace of the heat treatment section 4 with calcine petroleum coke lump and energizing it to raise the temperature in advance. As a result, the subsequently added granulated coal D is subjected to heat treatment as needed along with the introduction and flow, thereby increasing the conductivity. If it will be in such a state, even if the inside of the furnace of the heat processing part 4 will be switched to granulated coal D after that, it will be continuously and efficiently energized, and continuous heat treatment by direct current heating to granulated coal D is possible. Become.

  The granulated coal D passes through the heat generating zone 4d and is subjected to heat treatment to be graphitized. In the present embodiment, the graphitization temperature in the heat treatment section 4 is 2000 to 3000 ° C. A preferred graphitization temperature is in the range of 2400 to 3000 ° C. A more preferable graphitization temperature is in the range of 2600 to 3000 ° C, and a more preferable graphitization temperature is in the range of 2800 to 3000 ° C.

  In addition, the heat generating zone 4d of the present embodiment has a smaller capacity than an Atchison furnace in which a filler is filled to the size of a pool and can be easily maintained at a desired temperature. That is, in this embodiment, the temperature accuracy is very good, and it is possible to control to a desired temperature within the processing temperature range. When controlling the graphitization temperature, the preferred graphitization temperature varies depending on the desired use of the graphite powder. For example, the preferred graphitization temperature is 2200 to 2300 ° C, 2300 to 2400 ° C, 2500 to 2600 ° C, etc. Range. Thus, a preferable temperature range can be set according to the desired temperature.

  The amount of the granulated coal D passing through the heat treatment unit 4 is controlled by discharge by a rotary blade installed on the water cooling board 5b. That is, the heat treatment amount of the granulated coal D that passes through the heat generating zone 4d is quantitatively controlled by the rotary blades installed on the water cooling board 5b, and the discharge speed is controlled to an arbitrary speed in the range of 50 to 200 kg / h. .

  In the heat treatment part 4, a uniform temperature zone is formed in the heat generating zone 4d by energization by the shapes and structures of the columnar upper electrode 4a, the cylindrical charging part 4e and the cylindrical lower electrode 4b. The granulated coal D passes through the heating zone 4d. That is, the granulated coal D is heated uniformly and realizes good graphitization.

  In the present embodiment, an inert gas such as argon gas or nitrogen gas is supplied from the gas blowing hole 4g formed in the upper electrode 4a and the gas blowing hole 5c near the upper end of the water cooling jacket 5a to the heat treatment portion. 4 can be blown into the furnace. Therefore, the gas volatilized from the carbon powder A can be effectively discharged from the furnace of the heat treatment unit 4. The graphitized granulated coal D1 moves to the cooling unit 5 through the discharge unit 4f. As described above, the capacity of the heat treatment section 4 as a continuous heat treatment furnace is 50 to 200 kg / h and enables continuous operation for several months.

[Cooling process]
The cooling unit 5 performs a cooling process. In the cooling step, the graphitized granulated coal D1 is cooled by the water cooling jacket 5a and the water cooling board 5b. The graphitized granulated coal D1 is sent to the powder generating unit 6 after cooling. The cooling time is not particularly limited, as long as it has a cooling capacity corresponding to 50 to 200 kg / h, which is the capacity of the heat treatment section 4 as a continuous heat treatment furnace.

[Powder production process]
The powder production | generation part 6 performs a powder production | generation process. In the powder production step, the graphitized granulated coal D1 is crushed to produce graphite powder E having a desired particle size. There is no problem if the amount of graphitized granulated coal D1 input to the powder generation unit 6 is adjusted in consideration of the facility capacity of the powder generation process and the speed of passing through the heat treatment unit 4, but for example when using a turbo mill The range is 150 to 250 kg / h.

  The average particle size and particle size distribution of the graphite powder E generated in the powder generating unit 6 is basically the same as the carbon powder A as a raw material, but the carbon powder A itself may be graphitized and contracted. In order to obtain the desired graphite powder E, the particle size distribution of the carbon powder A may be adjusted in advance in anticipation of graphitization. Moreover, since it is necessary to maintain the surface state of the particles after graphitization in principle, the powder generation unit 6 crushes the raw material M with a weaker force than when the raw material M is pulverized by the pulverization unit 9 to be carbon powder A. It is desirable to do.

Examples of the particle size distribution of the graphite powder E include d10: 4 μm, d50: 7 μm, and d90: 12 μm. Moreover, when the powder production | generation part 6 is made into a turbo mill, the rotation speed of a turbo mill is the range of 4000-9000 rpm, and the air volume is the range of 8-10 m < ³ > / min. The graphite powder E thus produced is sent out to the inspection unit 7.

[Inspection process]
The inspection unit 7 performs an inspection process. In the inspection process, the graphitization degree of the graphite powder E is measured by an X-ray measuring device. X-ray measurements are performed every 2 hours. Measurement objects of the inspection unit 7 include an interlayer distance d002 obtained by X-ray diffraction, a crystal thickness Lc in the c-axis direction, a size La in the a-axis direction, and the like.

  The measurement follows the Gakushin method (a method for measuring the lattice constant and crystallite size of carbon materials). The measurement results of the inspection unit 7 are fed back to the operating conditions of the combining unit 1, the granulating unit 2, the curing processing unit 3, the heat treatment unit 4, the cooling unit 5, and the powder generating unit 6, and in each unit, an appropriate processing speed and appropriate It becomes a judgment material for adjusting to a suitable processing temperature.

[Function and effect]
The effects of the first embodiment are as follows.
(A) It is possible to continuously produce graphite powder efficiently under a good working environment.
In the first embodiment, carbon powder A and binders B1 and B2 are mixed and combined to make composite C, and granulated coal D is made from this composite C. On top of that, graphite powder E can be continuously produced by graphitizing the granulated coal D and finally crushing the granulated coal D1 that has been graphitized.

  In this embodiment, compared with the case where a batch type Atchison furnace is used, the boxing work of carbon powder A having a poor working environment and the work of filling the box in the filling material in the furnace become unnecessary, and work efficiency is improved. Will improve. In addition, compared with the case where an Atchison furnace having a large pool size is used, in this embodiment, the electricity bill is low and the energy saving effect is remarkably high.

  Further, in the present embodiment, since a plurality of types of processes from compounding to graphitization are not performed sequentially step by step, but are performed continuously in parallel for a long time, the amount of compound produced It can only be graphitized and it is easy to control the adjustment of production. Furthermore, mass production on an industrial production scale is possible by long-term continuous operation.

(A) Granulated coal having a desired hardness can be easily produced.
In 1st Embodiment, since it was set as granulated coal D which combined carbon powder A reliably by using (alpha) corn starch as binder B1, granulated coal D1 which has suitable hardness after graphitization can be made. it can.

  In addition, α corn starch, which is a type of starch, becomes harder if moisture is removed after adding moisture to gelatinize. Therefore, by drying the granulated coal D, it can be cured and handling becomes easy. Therefore, a poor working environment when handling fine carbon powder A can be eliminated, special equipment is not required, and workability is greatly improved.

  As the hardness of the granulated coal D1 after graphitization, since it is pulverized into a powder to be graphite powder E, it is desirable that the granulated coal D1 be easily broken by the powder generation unit 6. However, if the granulated coal D1 is fragile, it collapses in the heat generating zone 4d and becomes clogged, so that continuous operation becomes difficult. On the other hand, when the granulated coal D1 is too hard, the crushability of the powder production | generation part 6 will fall and a yield will fall.

  Therefore, as the desired hardness of the graphitized granulated coal D1, a digital force gauge (manufactured by Imada Co., Ltd.) is used as a hardness measuring device, and the measurement speed (attachment dropping speed for compression) is 10 mm / min. Although the measured value is required to be 10 N (Newton) or more, the first embodiment can easily satisfy such a need.

  That is, in 1st Embodiment, granulated coal D1 of sufficient hardness can be obtained by making the quantity of the binder B1 with respect to the carbon powder A into the range of 3 weight% or more and less than 10 weight%. Specifically, the hardness measurement value is 10 N or more if it is 3 wt%, and the hardness measurement value is 14 N or more if it is 9 wt%. In addition, in order to make the granulated coal D1 after graphitization have a desired hardness, not only the amount of the binder B1 is changed according to the type of the carbon powder A, but also the processing temperature, processing speed, and granulation in the curing processing step. Adjust the operating conditions in the process. The binder B2 greatly contributes to the viscosity and fluidity of the composite necessary for obtaining good granulated coal, and has little influence on the hardness of the granulated coal D1 after graphitization.

  As a result, the heat treatment unit 4 can surely carry out the heat treatment without causing clogging, and the yield of the crushing treatment in the powder production unit 6 is improved. As described above, according to the present embodiment, stability and workability can be improved with respect to the heat treatment of the granulated coal D and the pulverization treatment for returning the graphitized granulated coal D1 to a powder form. In the production of graphite powder E, excellent productivity and workability are exhibited, and economic efficiency is improved.

(C) Granulated charcoal that is difficult to block can be made.
In the first embodiment, the mixture C is made into granulated coal D and then charged into the heat treatment section 4. Since the granulated coal D has a granulated particle size of about 10 mm and a length of 10 to 15 mm, even if gas is generated from the granulated coal D during the heat treatment, compared with the case where the carbon powder A of μm order is added. The gas escapes upward from the gap between the granulated coals D, and there is no concern that carbon powder is fixed in the heat treatment part 4 due to the condensation of the gas.

  As a result, the granulated coal D is not clogged in the heat treatment part 4 and there is no possibility of clogging inside the heat treatment part 4. Moreover, since the granulated coal D is appropriately hardened in the present embodiment, it is difficult for collapse to occur when the inside of the heat treatment part 4 is moved from the upper part toward the lower part. Therefore, the granulated coal D collapses, generation | occurrence | production of the fine powder which becomes a cause of obstruction | occlusion can be suppressed, and heat processing can be implemented stably.

(D) Uniform heat treatment can be performed continuously over a long period of time.
In the heat treatment part 4, it is important that the granulated coal D flows down in the furnace while flowing. If there is a stagnation of raw materials, deposition due to segregation of fine powders, fixation due to condensation of the generated gas, etc. in the heat treatment part 4, the heat treatment part 4 is blocked. If the granulated coal D is clogged, a drift occurs, current distribution deteriorates, the heat efficiency is lowered, and uniform raw material flow and discharge are hindered. As a result, variation occurs in the processing temperature of the granulated coal D, not only non-uniform graphitization but also continuous operation becomes impossible.

  On the other hand, in the first embodiment, the granulated coal D is smooth with no irregularities on the surface, is cylindrical and has a uniform shape and size, and thus has good fluidity. There is no worry that such a malfunction will occur. Moreover, in the first embodiment, a uniform temperature zone of the highest temperature is formed at the upper end opening of the lower electrode 4b in the heating zone 4d by direct current heating, and all of the granulated coal D passes through this uniform temperature zone. By doing so, the granulated coal D is uniformly heated to the maximum temperature. Therefore, according to the first embodiment, it is possible to perform the heat treatment step continuously and stably, obtaining a good graphitized granulated coal D1, and producing a high-performance graphite powder E therefrom. be able to.

  Specifically, when using the heat treatment unit 4 of the present embodiment and comparing the length of the operation shutdown furnace order (number of days) in which the heat treatment operation is started and then suspended due to uneven flow or blockage of raw materials, d10 When Calcine Petroleum Coke Lumps having a particle size distribution of 0.6 mm, d50: 2.5 mm, and d90: 9 mm were used, the following test results were obtained. When the calcine petroleum coke lump was heat-treated in the heat treatment section 4 with the same processing conditions as it was, the average number of days of outage furnace was 4.3 days (minimum 3 days, maximum 5 days). Similarly, in the case of a material in which particles of 1 mm or less of the above-mentioned coke are cut, the average number of days of outage furnace is 6.3 days (minimum 3 days, maximum 10 days), and the material in which particles of 2 mm or less are cut is average 10. 8 days (minimum 2 days, maximum 42 days).

  On the other hand, the material obtained by cutting particles of 4 mm or less of the Calcine Petroleum Coke Lump averaged 36.7 days (minimum 25 days, maximum 69 days) until the shutdown furnace age. That is, when the heat treatment is performed in the heat treatment section 4, when the particle diameter is 4 mm or more compared to the case where particles of 4 mm or less are included, continuous operation can be performed over a long period of time from 3.5 times to 9 times.

  From these results, it has been found that it is important not to contain particles of 4 mm or less in order to maintain good fluidity of the material in the furnace and to enable long-term continuous operation without causing clogging due to segregation or the like. It was. Therefore, in this embodiment, since the particle diameter of the granulated coal D is 4 mm or more, preferably 10 mm or more, a uniform heat treatment can be continuously performed over a long period of time. In addition, it is clear that the smooth surface of the granulated coal D is advantageous for long-term continuous operation as compared with Calcine Petroleum Coke having irregularities on the grain surface.

(E) No heat treatment is required in the combining step.
When starch is used as the binder B1, a paste is formed by adding moisture and heat, but the α corn starch powder, which is the binder B1 of the first embodiment, is gelatinized only by adding water or hot water B3. In addition, it is not necessary to heat in the combining step, and the work can be simplified.

(F) The graphitized granulated coal D1 can be prevented from being oxidized by cooling the graphitized granulated coal D1.
In order to stabilize the performance of the graphite powder E having stable performance, it is extremely important to prevent the granulated coal D1 from being oxidized. In the first embodiment, by cooling the graphitized granulated coal D1 in the cooling unit 5, it is possible to prevent oxidation of the graphitized granulated coal D1, and to continuously and efficiently perform stable graphite. It is possible to obtain powder E. Here, the graphitized product must be cooled and taken out. When using an Atchison furnace, it is usually necessary to cool over several days to a temperature at which the treated product is not oxidized after the graphitization treatment.

  On the other hand, in the first embodiment, the inside of the heat treatment section 4 and the cooling section 5 is filled with these gases by the generated gas from the granulated coal D and the inert gas blowing from the gas blowing holes 4g and 5c. It has been a non-oxidizing atmosphere. Therefore, the graphitized granulated coal D1 is cooled in a non-oxidizing atmosphere in the process of passing through the inside of the furnace of the heat treatment section 4 and the inside of the cooling section 5, and is 50 to 200 kg / h without being oxidized. Discharged at a speed of. In other words, it is possible to continuously perform a cooling process that has been cooled for several days in a conventional manner at a high speed, and it is possible to quickly produce high-performance graphite powder E.

(2) Other Embodiments The present invention is not limited to the above-described embodiment, and can be implemented in various other forms. For example, the type of the binder B1 can be selected as appropriate. As starch powder, wheat starch, rice starch, legume starch, potato starch, etc., starch starch obtained by pre-gelatinizing them, saccharides, etc. are combined if carbonized. Any material may be used as long as it has a property, and a plurality of types may be used in combination. Further, by adding a hardening treatment at several hundred degrees before the heat treatment section 4, it is possible to expand the options to the binder B 1 for pitch, solid resin, the binder B 2 for coal tar, liquid resin, and the like.

  Further, in order to reliably prevent the granulated coal D from being blocked in the heating unit 4, the size of the diameter of the granulated coal D is 4 mm or more, preferably 10 mm or more, or the aspect ratio is 1 to 1. 2 is preferable. Further, the shape of the granulated coal D may be not only a columnar shape but also a sphere. If the shape of the granulated coal D is a sphere, the treatment temperature in the heating unit 4 can be uniformly received, which is advantageous from the viewpoint of stability of performance.

  Furthermore, the speed at which the granulated coal D moves in the heat treatment section 4 is not limited by the shape and size of the granulated coal D, but also the components on the heat treatment section 4 side, for example, the shape and diameter of the upper electrode 4a. The size can be adjusted as appropriate depending on the size and position, the opening area of the lower electrode 4b, and the difference in diameter between the input portion 4e and the discharge portion 4f.

DESCRIPTION OF SYMBOLS 1 ... Composite part 2 ... Granulation part 3 ... Curing process part 4 ... Heat treatment part 5 ... Cooling part 6 ... Powder production | generation part 7 ... Inspection part 8 ... Raw material tank 9 ... Grinding part 10 ... Kneader 11 ... Raw material supply pipe 12a ... Binder Supply pipe 12b ... Water supply pipe 13 ... Atchison furnace 14 ... Electrode 15 ... Filler 16 ... Box A ... Carbon powder B1, B2 ... Binder B3 ... Water or hot water C ... Compound D ... Granulated coal D1 ... Graphitized structure Granular coal E ... Graphite powder M ... Raw material

Claims (7)

A combined part for adding a liquid binder to a mixture of the raw material carbon powder and a solid binder and combining them to produce a composite;
A granulated portion in which the composite is a granulated coal having a diameter of 4 mm or more ;
A curing treatment part for heat-curing the granulated coal before heat treatment;
A heat treatment part for heat-treating the dried granulated coal;
A powder generating part for pulverizing the granulated coal graphitized into graphite powder ,
The curing curing temperature of the processing unit is cured by heating the granulated charcoal production apparatus of the graphite powder, wherein to Rukoto and less than 170 ° C.. A cooling unit for cooling the granulated coal to heat treatment apparatus for manufacturing a graphite powder according to claim 1, characterized in that cooling the granulated carbon in a non-oxidizing atmosphere in the cooling section. The said solid binder is 3 weight% or more and less than 10 weight%, The manufacturing apparatus of the graphite powder of Claim 1 or 2 characterized by the above-mentioned. The apparatus for producing graphite powder according to any one of claims 1 to 3 , wherein the granulated coal has a cylindrical shape with a smooth surface and has a uniform shape and size. The apparatus for producing graphite powder according to any one of claims 1 to 4, wherein the solid binder is starch. The heat treatment part has an upper electrode and a lower electrode,
  The apparatus for producing graphite powder according to any one of claims 1 to 5, wherein the granulated coal is heat-treated by energizing the upper electrode and the lower electrode. Using the manufacturing apparatus according to any one of claims 1 to 6 ,
A combined part treatment in which a liquid binder is added to a mixture obtained by mixing 3 wt% or more and less than 10 wt% of a solid binder with respect to the carbon powder as a raw material and combined to produce a combined product;
A granulation treatment in which the composite is a granulated coal having a diameter of 4 mm or more;
A curing treatment for heat-curing the granulated coal before heat treatment;
Heat treatment for heat-treating the dried granulated coal;
A powder generation treatment for pulverizing the granulated coal that has been graphitized into graphite powder;
In the hardening treatment, the graphite powder manufacturing apparatus is characterized in that a hardening treatment temperature for heating and hardening the granulated coal is less than 170 ° C.

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