Graphite purification equipment and method of use thereof

Abstract

The present invention discloses a graphite purification device and a method for using the same. The graphite purification device comprises at least one furnace body, wherein the furnace body has a graphite muffle, a heat preservation layer and a furnace shell which are sequentially arranged from the inside to the outside, and a purification chamber is formed inside the graphite muffle; an induction heater is arranged between the heat preservation layer and the furnace shell, and the induction heater can generate an alternating magnetic field when an alternating current is passed through, and the graphite muffle generates Joule heat; a feed pipe, a discharge pipe, an air inlet pipe and an air outlet pipe which pass through the outside of the furnace shell to the purification chamber are arranged on the furnace body, and the materials and gases entering from the feed pipe and the air inlet pipe respectively flow in opposite directions in the purification chamber, and a shunt structure for shunting the gas in the air inlet pipe and evenly distributing it in the purification chamber is arranged on the side wall of one end of the graphite muffle near the air inlet pipe. The present invention can realize the convection of materials and gases in the furnace, and an induction heater and a shunt structure are arranged, and the invention has the characteristics of accurate temperature control, fast response speed, high purification efficiency and good purification effect.

Description

Technical Field

[0001] The present invention relates to the technical field of graphite purification, and in particular to a graphite purification device and a use method thereof. Background Art

[0002] High-purity graphite is in high demand in many fields such as metallurgy, aerospace, and new energy. Therefore, the purification of graphite is of great significance to the development and progress of industry.

[0003] At present, the method for preparing high-purity graphite is mainly based on high temperature combined with chemical methods, in which the temperature field is provided in two ways: resistance heating and induction heating. Among them, resistance heating has a simple structure, but low thermal efficiency, large energy consumption, slow temperature control response speed, inaccurate temperature control, and large deviations; induction heating is non-contact heating, with high thermal efficiency, simple operation, fast heating, fast temperature control response speed, and relatively accurate control.

[0004] Since graphite has extremely high melting and boiling points, with a melting point of 3850±50℃ and a boiling point of 4500℃, some of its impurity elements will escape in gaseous form at a high temperature of 2800℃, such as magnesium (Mg), aluminum (Al), calcium (Ca), manganese (Mn), iron (Fe), nickel (Ni), etc. However, there are a few impurities that cannot escape at high temperatures, such as boron (B). The main forms of B in graphite are boron carbide (B4C) clusters, boron atoms (sub-B) in substituted carbon lattices, and boron oxygen bonds (BO). The thermal stability of clusters is higher than that of sub-B and BO. In non-boron-doped carbon materials, boron atoms mainly exist in the form of clusters, which are difficult to completely remove at high temperatures. Freon and the like need to be introduced for halogenation reactions, thereby converting them into boron fluoride (BF3) with lower melting and boiling points. Therefore, the main method of high temperature combined with chemical purification of graphite is to directly load the graphite powder into a graphite crucible, heat it to 2300-3000℃ in a purification furnace with inert protective gas and Freon, and keep it for a period of time. The impurities in the graphite will overflow, thereby achieving the purification of the graphite.

[0005] However, the existing graphite purification equipment has simple functions, poor stability and low heating efficiency, and the operating temperature is less than 2300°C. There are very few ultra-high temperature graphite purification equipment that can be used for graphite purification. In addition, the existing ultra-high temperature graphite purification equipment has relatively complex structure, poor equipment expandability, difficulty in later maintenance, slow heating control response speed, difficulty in precise temperature control, poor purification capacity and gas uniformity, etc. Summary of the invention

[0006] The purpose of the present invention is to provide a graphite purification device and a method for using the same, which at least solves one of the problems existing in the prior art, namely, the relatively complex structure of the graphite purification device, the uneven internal gas distribution, the limited heating efficiency and the low temperature control accuracy.

[0007] The above-mentioned purpose of the present invention can be achieved by adopting the following technical solutions:

[0008] The present invention provides a graphite purification device, comprising at least one furnace body, wherein the furnace body has a graphite muffle, a thermal insulation layer and a furnace shell which are arranged in sequence from the inside to the outside, and a purification chamber is formed inside the graphite muffle; an induction heater is arranged between the thermal insulation layer and the furnace shell, and the induction heater can generate an alternating magnetic field when an alternating current is passed through, and make the graphite muffle generate Joule heat; a feed pipe, a discharge pipe, an air inlet pipe and an air outlet pipe which pass through from the outside of the furnace shell to the purification chamber are arranged on the furnace body, and the material entering from the feed pipe and the gas entering from the air inlet pipe have opposite flow directions in the purification chamber, and a diversion structure is arranged on the side wall of one end of the graphite muffle close to the air inlet pipe, and the diversion structure is used to divert the gas in the air inlet pipe and evenly distribute it in the purification chamber.

[0009] Preferably, the graphite purification equipment comprises a plurality of the furnace bodies arranged in a stacked manner, and the discharge pipe of the furnace body located at the upper side of two adjacent furnace bodies is connected to the feed pipe of the furnace body located at the lower side.

[0010] Preferably, when the graphite purification equipment is in operation, the furnace temperature of the lower furnace body among the two adjacent furnace bodies is not lower than the furnace temperature of the upper furnace body.

[0011] Preferably, the diversion structure includes at least one diversion annular groove and a plurality of diversion holes connected between the purification chamber and at least one of the diversion annular grooves, at least one of the diversion annular grooves is arranged on the outer wall of the graphite muffle and is connected to the air inlet pipe, and the plurality of diversion holes are evenly distributed along the circumferential direction of the graphite muffle.

[0012] Preferably, in a direction from the outer wall to the inner wall of the graphite muffle, the plurality of diversion holes are arranged to be inclined downward along the direction of gravity.

[0013] Preferably, the furnace shell comprises an inner furnace shell and an outer furnace shell, and a cooling chamber for accommodating a cooling medium is formed between the inner furnace shell and the outer furnace shell.

[0014] Preferably, the graphite muffle has a constant diameter section and a frustum section arranged in sequence along the gravity direction, the constant diameter section is connected to the large diameter end of the frustum section, the constant diameter section is connected to the feed pipe and the air outlet pipe, and the frustum section is connected to the discharge pipe and the air inlet pipe.

[0015] Preferably, the graphite muffle is made of isostatically pressed high-purity graphite, and when the graphite purification equipment is in operation, the maximum reaction temperature in the purification chamber is not less than 2800°C.

[0016] Preferably, the thermal insulation layer includes a first graphite soft felt layer, a graphite short fiber hard felt layer and a second graphite soft felt layer which are arranged in sequence from the inside to the outside.

[0017] Preferably, the induction heater comprises a spiral copper tube and an electrode wood, the spiral copper tube is arranged around the insulation layer, the spiral copper tube is connected to the furnace shell through the electrode wood, and when the induction heater is in a state of passing an alternating current, cooling water flows through the spiral copper tube.

[0018] Preferably, the graphite purification equipment further comprises a cooling system and a material receiving system, wherein the cooling system is connected between the material receiving system and a discharge pipe of the furnace body located at the bottom, and the cooling system is used to cool the purified material.

[0019] Preferably, the cooling system comprises at least one cooler having an inner shell and an outer shell, an air-cooling chamber is formed in the inner shell, a water-cooling chamber is formed between the inner shell and the outer shell, and the air-cooling chamber is connected to the discharge pipe.

[0020] Preferably, the graphite purification equipment further comprises a gas supply system and an exhaust gas system, wherein the gas supply system is used to provide corresponding gases to the purification chamber and the air-cooling chamber, and the exhaust gas system is used to recover exhaust gases from the purification chamber and the air-cooling chamber.

[0021] Preferably, the graphite purification equipment also includes an electrical system having a temperature measuring element, a controller and a heating power supply, the heating power supply is connected to the induction heater, the temperature measuring probe of the temperature measuring element extends into the purification chamber, and the controller can regulate the power of the heating power supply according to the temperature signal fed back by the temperature measuring element.

[0022] Preferably, a control component for controlling the discharge is provided on the discharge pipe, and the control component is electrically connected to the controller. The controller controls the operation of the control component according to a preset reaction time, so that the purified material in the purification chamber flows out from the discharge pipe.

[0023] Preferably, the control member is a blocking plug plate inserted on the discharge pipe, and the blocking plug plate can move along the radial direction of the discharge pipe to open or cut off the discharge channel of the discharge pipe.

[0024] Another object of the present invention is to provide a method for using a graphite purification device, which is applicable to the graphite purification device as described above, and includes: turning on the induction heater to make the temperature in the purification chamber at the reaction temperature required for material purification; cutting off the discharge channel of the discharge pipe, and introducing protective gas into the purification chamber through the air inlet pipe to replace the gas in the purification chamber; after the gas replacement in the purification chamber is completed, introducing material into the purification chamber, and increasing the heating power of the induction heater to stabilize the temperature in the purification chamber at the reaction temperature required for material purification; after the temperature in the purification chamber is stabilized at the reaction temperature required for material purification, introducing gas required for material purification atmosphere into the purification chamber at a set flow rate to put the material into a purified state.

[0025] Preferably, the gas required for the material purification atmosphere is a mixed gas formed by mixing a reaction gas and a protective gas in a preset ratio.

[0026] Preferably, the method for using the graphite purification equipment also includes: after the purification time of the material in the purification chamber reaches a preset reaction time or the reaction gas reaches a preset intake amount, the discharge channel of the discharge pipe is opened to allow the material to flow out of the discharge pipe and enter the next purification chamber of the furnace body for further purification, or enter the material receiving equipment for post-processing and storage.

[0027] The characteristics and advantages of the present invention are: the graphite purification equipment provided by the present invention is provided with an induction heater so that the graphite muffle generates Joule heat by itself under electromagnetic induction, provides the temperature field required for material purification in the purification chamber, realizes contactless heating, and has the characteristics of high thermal efficiency, fast heating, accurate temperature control and fast response speed; through the relative position setting of the feed pipe, the discharge pipe, the air inlet pipe and the air outlet pipe, the convection of the material entering from the feed pipe and the gas entering from the air inlet pipe in the purification chamber is realized to increase the contact mixing degree between the material and the gas, and ensure the material purification effect; and through the diversion structure arranged on the graphite muffle, the gas is evenly distributed in the purification chamber, the material purification reaction is more sufficient, and the material purification efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a structural schematic diagram of a graphite purification device provided in an embodiment of the present invention;

[0030] Figure 2 It is a structural schematic diagram of a furnace body in a graphite purification device provided in an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of a flow splitting structure on a graphite muffle in a graphite purification device provided in an embodiment of the present invention;

[0032] Figure 4 for Figure 3 AA section view.

[0033] Description of Figure Numbers:

[0034] 1. Furnace body; 11. Graphite muffle; 111. Diverter ring groove; 112. Diverter hole; 12. Insulation layer; 13. Furnace shell; 14. Induction heater; 141. Spiral copper tube; 142. Electrode wood; 15. Feed pipe; 16. Discharge pipe; 161. Blocking plug plate; 17. Inlet pipe; 18. Outlet pipe; 19. Support structure;

[0035] 2. Cooling system; 21. Cooler;

[0036] 3. Material collection system;

[0037] 4. Gas supply system;

[0038] 5. Exhaust system;

[0039] 6. Electrical system; 61. Temperature measuring element. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figures 1 to 4As shown, the present invention provides a graphite purification device, comprising at least one furnace body 1, the furnace body 1 having a graphite muffle 11, a heat preservation layer 12 and a furnace shell 13 arranged in sequence from the inside to the outside, and a purification chamber is formed inside the graphite muffle 11; an induction heater 14 is arranged between the heat preservation layer 12 and the furnace shell 13, and the induction heater 14 can generate an alternating magnetic field when an alternating current is passed through, and the graphite muffle 11 generates Joule heat; a feed pipe 1 is provided on the furnace body 1, which passes through the outside of the furnace shell 13 to the purification chamber. 5. A discharge pipe 16, an air inlet pipe 17 and an air outlet pipe 18. The feed pipe 15 and the air outlet pipe 18 are located at the upper part of the graphite muffle 11, and the discharge pipe 16 and the air inlet pipe 17 are located at the lower part of the graphite muffle 11, so that the material entering from the feed pipe 15 and the gas entering from the air inlet pipe 17 have opposite flow directions in the purification chamber; a diversion structure is provided on the side wall of one end of the graphite muffle 11 close to the air inlet pipe 17, and the diversion structure is used to divert the gas in the air inlet pipe 17 and evenly distribute it in the purification chamber. In this way, by setting the induction heater 14, the graphite muffle 11 generates Joule heat by itself under electromagnetic induction, provides the temperature field required for material purification in the purification chamber, realizes contactless heating, and has the characteristics of high thermal efficiency, fast heating, accurate temperature control and fast response speed; by setting the relative positions of the feed pipe 15, the discharge pipe 16, the air inlet pipe 17 and the air outlet pipe 18, the convection of the material entering from the feed pipe 15 and the gas entering from the air inlet pipe 17 in the purification chamber is realized to increase the contact mixing degree between the material and the gas, and ensure the material purification effect; and by the diversion structure set on the graphite muffle 11, the gas is evenly distributed in the purification chamber, the material purification reaction is more sufficient, and the material purification efficiency is improved. Among them, the insulation layer 12 is used to prevent the heat generated by the graphite muffle 11 from being transferred outward to slow down the heat loss inside the graphite muffle 11, and at the same time make the induction heater 14 work in a temperature field with a lower temperature. In this embodiment, the insulation layer 12 is made of high temperature resistant graphite felt.

[0042] Specifically, the heat transferred inward by the high-temperature graphite muffle 11 is mainly absorbed by the material and gas through heat radiation, heat conduction and heat convection. After reaching a certain temperature, the impurities in the material will react with the reaction gas and gasify to achieve material purification. Among them, since the insulation layer 12 is made of graphite felt and has a certain conductivity, the insulation layer 12 will also generate Joule heat. In order to ensure the temperature field required for material purification in the purification chamber, the frequency of the alternating current passed into the induction heater 14 should be able to allocate more power to the muffle. Therefore, the frequency of the alternating current passed into the induction heater 14 cannot be too high. For graphite purification, when the temperature is higher than 2550°C, the impurities in the graphite react with the reaction gas (such as halogen gases such as fluorine gas) and gasify to achieve graphite purification.

[0043] According to a preferred embodiment of the present invention, Figure 1As shown, the graphite purification equipment includes a plurality of furnace bodies 1 arranged in a stacked manner, and the discharge pipe 16 of the furnace body 1 located on the upper side of two adjacent furnace bodies 1 is connected to the feed pipe 15 of the furnace body 1 located on the lower side. In this way, the interface design between each furnace body 1 is consistent, and the interface is stepped, which is convenient for expansion and use while reducing the heat loss of the interface; by arranging multiple furnace bodies 1 in series and utilizing the independent air intake and exhaust of each furnace body 1, the secondary contamination of the material during graded purification in each furnace body 1 is avoided, and the graded purification effect of the material is ensured; each furnace body 1 arranged in series has strong independence, good independent temperature control effect, and is convenient for later maintenance and good interchangeability. Among them, an independent support structure 19 made of carbon-carbon material is provided at the bottom of each furnace body 1, so as to play a certain heat insulation role while improving the support strength of the furnace body 1, reduce the mutual influence between the furnace bodies 1, and help to ensure the independent temperature control effect of each furnace body 1. Preferably, each furnace body 1 is provided with a weighing device, and when the weighing data of the weighing device of the furnace body 1 reaches a set value, the discharge channel of the discharge pipe 16 of the previous furnace body 1 is cut off.

[0044] According to a preferred embodiment of the present invention, when the graphite purification equipment is in operation, the temperature inside the lower furnace body 1 of two adjacent furnace bodies 1 is not lower than the temperature inside the upper furnace body 1, so that the material can obtain a better graded purification effect.

[0045] According to a preferred embodiment of the present invention, Figure 3 and Figure 4 As shown, the flow diversion structure includes at least one flow diversion annular groove 111, and a plurality of flow diversion holes 112 connected between the purification chamber and the at least one flow diversion annular groove 111. At least one flow diversion annular groove 111 is arranged on the outer wall of the graphite muffle 11 and is connected to the air inlet pipe 17. The plurality of flow diversion holes 112 are evenly distributed along the circumferential direction of the graphite muffle 11. Specifically, a groove is provided on the outer wall of the graphite muffle 11, and the groove cooperates with the heat preservation layer 12 surrounding the outside of the graphite muffle 11 to form the flow diversion annular groove 111. The gas entering the air inlet pipe 17 enters the inside of the graphite muffle 11 from each flow diversion hole 112 after being diverted by the flow diversion annular groove 111, so that the gas is evenly distributed in the graphite muffle 11, ensuring the mixing degree of the gas and the material, and improving the material purification efficiency.

[0046] According to a preferred embodiment of the present invention, Figure 4 As shown, from the outer wall to the inner wall of the graphite muffle 11, multiple diverter holes 112 are arranged to be inclined downward along the gravity direction to prevent the material from entering the diverter holes 112 during the feeding process and affecting the gas inflow, resulting in uneven gas distribution in the graphite muffle 11 or even no gas inflow, thereby affecting the material purification efficiency and purification effect.

[0047] According to a preferred embodiment of the present invention, Figure 2As shown, the furnace shell 13 includes an inner furnace shell 13 and an outer furnace shell 13, and a cooling chamber for accommodating a cooling medium is formed between the inner furnace shell 13 and the outer furnace shell 13. Specifically, the furnace shell 13 is a double-layer water-cooled vertical barrel-shaped structure, the inner furnace shell 13 is made of non-magnetic material 304 stainless steel, and the outer layer is made of carbon steel. When the graphite purification equipment is in operation, circulating cooling water is passed through the cooling chamber to prevent overheating due to insufficient local cooling, and to reduce the surface temperature of the outer furnace shell 13, thereby reducing the regional ambient temperature when the equipment is continuously working, so as to protect the pipelines and other facilities outside the equipment.

[0048] According to a preferred embodiment of the present invention, Figure 2 As shown, the graphite muffle 11 has a constant diameter section and a frustum section arranged in sequence along the gravity direction, the constant diameter section is connected to the large diameter end of the frustum section, the constant diameter section is connected to a feed pipe 15 and an outlet pipe 18, and the frustum section is connected to a discharge pipe 16 and an inlet pipe 17. Among them, the graphite muffle 11 can be connected and constructed in an upper and lower splicing manner to reduce the cost and processing difficulty. Further, the diverter ring groove 111 is formed at the splicing position to enhance the uniformity of the gas introduced and improve the material purification effect. By setting a frustum section with a certain inclination angle to reduce the friction between the material and the inner wall of the graphite muffle 11, it is conducive to the smooth outflow of the purified material, so as to reduce the adhesion and accumulation of the material on the inner wall of the graphite muffle 11, thereby affecting the purification effect of the subsequent material. Furthermore, the adhesion and accumulation of the purified material on the inner wall of the graphite muffle 11 can be avoided by improving the smoothness of the inner wall of the graphite muffle 11.

[0049] According to a preferred embodiment of the present invention, the graphite muffle 11 is made of isostatically pressed high-purity graphite to meet the material selection requirements of high strength, high temperature resistance and no contamination of materials. When the graphite purification equipment is in working state, the maximum reaction temperature in the purification chamber is not less than 2800° C. In this embodiment, the maximum reaction temperature in the purification chamber is 2850° C., so that the material can be purified under ultra-high temperature conditions, which is conducive to improving the degree of purification of the material.

[0050] According to a preferred embodiment of the present invention, the thermal insulation layer 12 includes a first graphite soft felt layer, a graphite short fiber hard felt layer, and a second graphite soft felt layer, which are sequentially arranged from the inside to the outside. Specifically, the temperature field of the graphite purification equipment is provided by the induction heater 14. The thermal insulation layer 12, which is made of the first graphite soft felt layer, the graphite short fiber hard felt layer, and the second graphite soft felt layer, which are sequentially arranged from the inside to the outside, is selected. While reducing the exchange cost of the innermost consumables, it takes into account the thermal insulation effect and heat resistance, and can also reduce the eddy current generated by the thermal insulation layer 12 in the magnetic field, thereby generating Joule heat and extending the service life of the thermal insulation layer 12.

[0051] According to a preferred embodiment of the present invention, Figure 2As shown, the induction heater 14 includes a spiral copper tube 141 and an electrode wood 142. The spiral copper tube 141 is arranged around the insulation layer 12, and the spiral copper tube 141 is connected to the furnace shell 13 through the electrode wood 142. When the induction heater 14 is in a state of passing alternating current, cooling water flows through the spiral copper tube 141, so that the heat generated by environmental radiation and the heat generated by the spiral copper tube 141 itself is released into the cooling water, thereby ensuring the normal working temperature of the copper tube and extending its service life.

[0052] According to a preferred embodiment of the present invention, Figure 1 As shown, the graphite purification equipment also includes a cooling system 2 and a material collection system 3, and the cooling system 2 is connected between the material collection system 3 and the discharge pipe 16 of the furnace body 1 located at the bottom, and the cooling system 2 is used to cool the purified material. Specifically, after the material completes the purification and cooling process, it enters the material collection system 3 for processing and storage. Preferably, the material collection system 3 is a negative pressure material collection system 3 composed of a vacuum feeder, a vortex fan, a pipeline, etc., and the whole adopts a sealed structure design. The vacuum feeder chamber is divided into an upper chamber and a lower chamber by a filter element and a filter disc, the upper chamber is connected to a vortex fan, and the lower chamber is connected to a temporary storage bin. The vacuum feeder draws the internal chamber into a negative pressure state under the action of the vortex fan, so that the cooled material is filtered in the upper chamber and sucked into the lower chamber. The material collection system 3 controls the bottom gate valve of the lower chamber to open or close according to whether the weight of the temporary storage bin reaches the limit, so as to realize the automatic control of the material falling into the temporary storage bin.

[0053] According to a preferred embodiment of the present invention, the cooling system 2 includes at least one cooler 21, the cooler 21 has an inner shell and an outer shell, an air-cooling chamber is formed in the inner shell, a water-cooling chamber is formed between the inner shell and the outer shell, and the air-cooling chamber is connected to the discharge pipe 16. Specifically, Figure 1 As shown, the cooling system 2 includes two coolers 21 arranged in series along the material discharge direction, and both coolers 21 have an inner shell and an outer shell, so as to facilitate the introduction of cooling air and cooling water into the inner shell and between the inner shell and the outer shell, respectively, to achieve air cooling and water cooling in parallel, and to improve the cooling rate of the purified material. Among them, the cooler 21 located at the upstream end is a slow cooling cooler 21, and the cooler 21 located at the downstream end is a fast cooling cooler 21. The slow cooling cooler 21 is provided with a thicker graphite lining to prevent secondary contamination of the material at high temperature, and the external material is stainless steel; the fast cooling cooler 21 is provided with a thinner graphite lining to improve the heat exchange efficiency while preventing secondary contamination of the material, and the external material is stainless steel, and the cooling rate is faster.

[0054] According to a preferred embodiment of the present invention, Figure 1As shown, the graphite purification equipment also includes a gas supply system 4 and an exhaust system 5. The gas supply system 4 is used to provide corresponding gases to the purification chamber and the air-cooling chamber, and the exhaust system 5 is used to recover the exhaust gas of the purification chamber and the air-cooling chamber. Specifically, in the process of high-temperature thermochemical purification of materials, some impurities with lower melting and boiling points will be directly gasified at high temperatures, and some impurities with higher melting and boiling points will react chemically with the reaction gas to generate chemical substances with lower melting and boiling points and gasify at high temperatures. The volatiles formed by the gasification of the two and the gas introduced into the purification chamber converge near the outlet of the gas outlet pipe 18 to form exhaust gas and flow into the exhaust gas treatment system from the gas outlet pipe 18. After the exhaust gas is filtered in multiple stages in the exhaust gas treatment system, some solid impurities with higher melting and boiling points are first collected at the furnace exit position, and the remaining impurities are continuously captured and absorbed, and finally meet the discharge standard, taking into account the realization of environmental protection goals.

[0055] According to a preferred embodiment of the present invention, Figure 1 As shown, the graphite purification equipment also includes an electrical system 6 having a temperature measuring element 61, a controller and a heating power supply. The heating power supply is connected to the induction heater 14. The temperature measuring probe of the temperature measuring element 61 extends into the purification chamber. The controller can adjust the power of the heating power supply according to the temperature signal fed back by the temperature measuring element 61. Specifically, the controller is also electrically connected to the cooling system 2 and the gas supply system 4, so that during the entire purification process of the material, the controller can realize dynamic coordinated control of the temperature field, air intake and cooling according to the purification process. Exemplarily, when external environmental factors cause the heat dissipation to accelerate and the temperature has a downward trend, the controller will immediately control the heating power supply to increase the heating power of the induction heater 14, and at the same time control the gas supply system 4 to appropriately reduce the reaction gas intake flow rate to prevent the incomplete reaction due to the temperature reduction and the generation of too much unreacted gas, and fine-tune the pipeline valve of the cooling system 2 to control the flow of the cooling medium to maintain the stable operation of the entire purification process. In this embodiment, the temperature measuring element 61 in the furnace body 1 when the temperature inside the furnace is 1000° C. or below is a thermocouple, and the temperature measuring element 61 in the furnace body 1 when the temperature inside the furnace is above 1000° C. is an infrared thermometer.

[0056] Preferably, the controller independently controls the heating power supply of each furnace body 1 to facilitate independent temperature control of the temperature field required for graded purification. Further, the heating power supply of each furnace body 1 is designed to be a same-frequency and same-phase power supply to reduce the influence of mutual inductance, thereby obtaining a better graded purification effect.

[0057] According to a preferred embodiment of the present invention, a control element for controlling the discharge is provided on the discharge pipe 16, and the control element is electrically connected to the controller, and the controller controls the operation of the control element according to the preset reaction time, so that the purified material in the purification chamber flows out from the discharge pipe 16. In this way, the material in the purification chamber is ensured to be completely purified.

[0058] According to a preferred embodiment of the present invention, Figure 1 and Figure 2 As shown, the control member is a blocking plug plate 161 inserted on the discharge pipe 16, and the blocking plug plate 161 can move along the radial direction of the discharge pipe 16 to open or cut off the discharge channel of the discharge pipe 16. Specifically, the controller controls the radial movement of the blocking plug plate 161 according to the preset reaction time to realize automatic control of the discharge timing and discharge speed.

[0059] Another object of the present invention is to provide a method for using a graphite purification device, which is applicable to the above-mentioned graphite purification device, including: turning on the induction heater 14 to make the temperature in the purification chamber at the reaction temperature required for material purification; cutting off the discharge channel of the discharge pipe 16, introducing protective gas into the purification chamber through the air inlet pipe 17, and replacing the gas in the purification chamber; after the gas replacement in the purification chamber is completed, introducing materials into the purification chamber, and increasing the heating power of the induction heater 14, so that the temperature in the purification chamber is stabilized at the reaction temperature required for material purification; after the temperature in the purification chamber is stabilized at the reaction temperature required for material purification, introducing the gas required for material purification atmosphere into the purification chamber at a set flow rate, so that the material enters a purification state. Among them, before the equipment is put into use, a sealing detector is used to ensure the sealing of the purification chamber, and the graphite purification equipment is put into use after ensuring that the sealing of the purification chamber meets the requirements. In this embodiment, the oxygen analyzer is used to detect whether the oxidation content in the purification chamber reaches 10ppm or less to determine whether the gas replacement is completed.

[0060] For example, the set temperature in a certain furnace body 1 is 2500°C. First, protective gas is introduced into the purification chamber of the furnace body 1 for gas replacement, and then the material is introduced. As the material is added, the temperature in the furnace drops, and the controller controls to increase the heating power of the induction heater 14. When the temperature in the furnace reaches 2500°C again, the controller controls the gas supply system 4 to start introducing the gas required for the material purification atmosphere at a set flow rate. The flow controller adjusts the air intake valve according to the air intake flow curve to accurately control the flow of the gas required for the material purification atmosphere to ensure the stability of the purification reaction. After the purification of the material in the furnace body 1 is completed, the reaction gas is switched to the protective gas.

[0061] According to a preferred embodiment of the present invention, the gas required for the material purification atmosphere is a mixed gas formed by mixing a reaction gas and a protective gas in a preset ratio. Preferably, a mixed gas with a preset ratio is obtained by controlling the flow rates of the reaction gas and the protective gas respectively during the introduction. The protective gas should neither react with graphite nor contaminate graphite. In this embodiment, the protective gas is argon.

[0062] According to a preferred embodiment of the present invention, the method for using the graphite purification equipment also includes: after the purification time of the material in the purification chamber reaches the preset reaction time or the reaction gas reaches the preset amount of introduction, the discharge channel of the discharge pipe 16 is opened, so that the material flows out from the discharge pipe 16 and enters the purification chamber of the next furnace body 1 for further purification, or enters the receiving device for post-processing and storage. Among them, the graded purification of the material specifically includes: when the purification time of the material in the purification chamber reaches the set reaction time or the set amount of reaction gas is introduced into the purification chamber, the purification reaction of the furnace body 1 is completed, and the controller simultaneously confirms that the next furnace body 1 is in an unloaded state, and controls the blocking plug plate 161 of the furnace body 1 to move and open the discharge channel of the discharge pipe 16, and the material enters the next furnace body 1. After the weighing device of the next furnace body 1 reaches the set value, the controller controls the blocking plug plate 161 of the furnace body 1 to reset and cut off the discharge channel of the discharge pipe 16. The material enters the next furnace body 1 for the same purification. After the last furnace body 1 is purified, the controller controls the blocking plug plate 161 of the last furnace body 1 to move to open the discharge channel of the discharge pipe 16, and the material enters the cooling system 2. The controller controls the pipeline valve of the cooling system 2 to respectively pass cooling air and cooling water into the air-cooling chamber and the water-cooling chamber of the cooler 21 for heat exchange, and adjusts the flow of cooling water and cooling air according to the temperature of the cooling air inlet and outlet water and the inlet and outlet air, so that the purified material is fully cooled.

[0063] Specifically, the controller heats each furnace body 1 to the corresponding set temperature according to the set temperature curve of the graded purification process. During the purification process, the electrical system 6 monitors the temperature change in real time. When the temperature exceeds the set range, the controller controls the heating power supply to adjust the power of the induction heater 14 in time to ensure that the entire purification process is carried out according to the set curve; at the same time, the gas supply system 4 starts to introduce the corresponding gas at a suitable temperature point according to the temperature change and process stage, and controls the flow rate according to the graded purification process flow curve. When the purification reaction enters the impurity volatilization stage, the temperature in the furnace is maintained at a high level and is relatively stable. The gas supply system 4 further adjusts the gas flow rate according to the process requirements to promote the volatilization of impurities. Among them, the process time of each furnace body 1 includes the feeding time, the purification time and the discharging time. The feeding time and the discharging time are not fixed, and are determined by the falling state of the material. The purification time can be fixed or non-fixed. When the purification time is non-fixed, the amount of the reaction gas introduced is the basis for the completion of the purification, and the amount of the reaction gas introduced is counted by the gas flow meter.

[0064] Based on the above description, the graphite purification equipment provided by the embodiment of the present invention has the following beneficial effects:

[0065] The graphite purification equipment provided in the embodiment of the present invention is provided with an induction heater 14, so that the graphite muffle 11 generates Joule heat by itself under electromagnetic induction, provides the temperature field required for material purification in the purification chamber, realizes contactless heating, and has the characteristics of high thermal efficiency, fast heating, accurate temperature control and fast response speed; through the relative position setting of the feed pipe 15, the discharge pipe 16, the air inlet pipe 17 and the air outlet pipe 18, the convection of the material entering from the feed pipe 15 and the gas entering from the air inlet pipe 17 in the purification chamber is realized to increase the contact mixing degree between the material and the gas, thereby ensuring the material purification effect; and through the diversion structure arranged on the graphite muffle 11, the gas is evenly distributed in the purification chamber. , the material purification reaction is more complete, thereby improving the material purification efficiency; by arranging multiple furnace bodies 1 in series, the independent air intake and exhaust of each furnace body 1 is utilized to avoid secondary contamination of the material during graded purification in each furnace body 1, thereby ensuring the graded purification effect of the material; the interface design between each furnace body 1 is consistent, and the interface is stepped, which is convenient for expanded use and can reduce the heat loss of the interface; each furnace body 1 arranged in series has strong independence, good independent temperature control effect, and is convenient for later maintenance and good interchangeability; in addition, the multiple furnace bodies 1 are arranged in series, which reduces the length and thermal expansion of the graphite muffle 11, which is conducive to extending the temperature measuring element 61 into the interior of the graphite muffle 11 and accurately measuring the reaction temperature of the purification chamber.

[0066] The above are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A graphite purification device, characterized in that: The invention comprises a plurality of furnace bodies arranged in layers, wherein the furnace bodies have a graphite muffle, a heat-insulating layer and a furnace shell arranged in sequence from the inside to the outside, and a purification chamber is formed inside the graphite muffle; An induction heater is arranged between the insulation layer and the furnace shell, and the induction heater can generate an alternating magnetic field when an alternating current is passed through it, and make the graphite muffle generate Joule heat; The furnace body is provided with a feed pipe, a discharge pipe, an air inlet pipe and an air outlet pipe which pass through the outside of the furnace shell to the purification chamber, and the flow directions of the material entering from the feed pipe and the gas entering from the air inlet pipe in the purification chamber are opposite, and a diversion structure is provided on the side wall of one end of the graphite muffle close to the air inlet pipe, and the diversion structure is used to divert the gas in the air inlet pipe and evenly distribute it in the purification chamber; The discharge pipe of the upper furnace body of the two adjacent furnace bodies is connected to the feed pipe of the lower furnace body; When the graphite purification equipment is in operation, the temperature inside the furnace of the lower furnace body among the two adjacent furnace bodies is not lower than the temperature inside the furnace of the upper furnace body; Each furnace body is provided with a weighing device, and when the weighing data of the weighing device of the furnace body reaches a set value, the discharge channel of the discharge pipe of the previous furnace body is cut off; The graphite purification equipment also includes an electrical system having a temperature measuring element, a controller and a heating power supply. The heating power supply is connected to the induction heater. The temperature measuring probe of the temperature measuring element extends into the purification chamber. The controller can regulate the power of the heating power supply according to the temperature signal fed back by the temperature measuring element. The controller heats each of the furnace bodies to a corresponding set temperature according to a set graded purification process temperature curve.

2. The graphite purification equipment according to claim 1, characterized in that: The diversion structure includes at least one diversion annular groove and a plurality of diversion holes connected between the purification chamber and at least one of the diversion annular grooves. At least one of the diversion annular grooves is arranged on the outer wall of the graphite muffle and is connected to the air inlet pipe. The plurality of diversion holes are evenly distributed along the circumferential direction of the graphite muffle.

3. The graphite purification equipment according to claim 2, characterized in that: In a direction from the outer wall to the inner wall of the graphite muffle, a plurality of the diversion holes are arranged to be inclined downward along the direction of gravity.

4. The graphite purification equipment according to claim 1, characterized in that: The graphite purification equipment also includes a cooling system and a material receiving system. The cooling system is connected between the material receiving system and a discharge pipe of the furnace body located at the bottom, and the cooling system is used to cool the purified material.

5. The graphite purification equipment according to claim 4, characterized in that: The cooling system includes at least one cooler, which has an inner shell and an outer shell. An air-cooling chamber is formed in the inner shell, a water-cooling chamber is formed between the inner shell and the outer shell, and the air-cooling chamber is connected to the discharge pipe.

6. The graphite purification equipment according to claim 5, characterized in that: The graphite purification equipment further comprises a gas supply system and an exhaust gas system, wherein the gas supply system is used to provide corresponding gases to the purification chamber and the air-cooling chamber, and the exhaust gas system is used to recover exhaust gases from the purification chamber and the air-cooling chamber.

7. The graphite purification equipment according to claim 6, characterized in that: The discharge pipe is provided with a control component for controlling the discharge, and the control component is electrically connected to the controller. The controller controls the operation of the control component according to a preset reaction time, so that the purified material in the purification chamber flows out from the discharge pipe.

8. The graphite purification equipment according to claim 7, characterized in that: The control component is a blocking plug plate inserted on the discharge pipe, and the blocking plug plate can move along the radial direction of the discharge pipe to open or cut off the discharge channel of the discharge pipe.

9. The graphite purification equipment according to claim 1, characterized in that: The graphite muffle is made of isostatically pressed high-purity graphite. When the graphite purification equipment is in working state, the maximum reaction temperature in the purification chamber is not less than 2800°C.

10. The graphite purification equipment according to claim 1, characterized in that: The heat-insulating layer comprises a first graphite soft felt layer, a graphite short fiber hard felt layer and a second graphite soft felt layer which are arranged in sequence from the inside to the outside.

11. The graphite purification equipment according to claim 1, characterized in that: The induction heater includes a spiral copper tube and an electrode wood. The spiral copper tube is arranged around the insulation layer and is connected to the furnace shell through the electrode wood. When the induction heater is in a state of passing an alternating current, cooling water flows through the spiral copper tube.

12. The graphite purification equipment according to claim 1, characterized in that: The graphite muffle has a constant diameter section and a frustum section arranged in sequence along the gravity direction, the constant diameter section is connected to the large diameter end of the frustum section, the constant diameter section is connected to the feed pipe and the air outlet pipe, and the frustum section is connected to the discharge pipe and the air inlet pipe.

13. The graphite purification equipment according to claim 1, characterized in that: The furnace shell comprises an inner furnace shell and an outer furnace shell, and a cooling chamber for accommodating a cooling medium is formed between the inner furnace shell and the outer furnace shell.

14. A method for using a graphite purification device, characterized in that: The method for using the graphite purification device is applicable to the graphite purification device according to any one of claims 1 to 13, comprising: Turn on the induction heater to make the temperature in the purification chamber reach the reaction temperature required for material purification; The discharge channel of the discharge pipe is cut off, and protective gas is introduced into the purification chamber through the air inlet pipe to replace the gas in the purification chamber; After the gas replacement in the purification chamber is completed, the material is introduced into the purification chamber, and the heating power of the induction heater is increased to stabilize the temperature in the purification chamber at the reaction temperature required for material purification; After the temperature in the purification chamber is stabilized at the reaction temperature required for material purification, the gas required for material purification atmosphere is introduced into the purification chamber at a set flow rate to put the material into a purified state.

15. The method for using the graphite purification device according to claim 14, characterized in that: The gas required for the material purification atmosphere is a mixed gas formed by mixing reaction gas and protective gas in a preset ratio.

16. The method for using the graphite purification device according to claim 15, characterized in that: The method for using the graphite purification device also includes: After the purification time of the material in the purification chamber reaches the preset reaction time or the reaction gas reaches the preset intake amount, the discharge channel of the discharge pipe is opened to allow the material to flow out of the discharge pipe and enter the next purification chamber of the furnace body for further purification, or enter the receiving equipment for post-processing and storage.

Images