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CN-121972081-A - Continuous purification system and method for high-purity graphite powder

CN121972081ACN 121972081 ACN121972081 ACN 121972081ACN-121972081-A

Abstract

The invention discloses a continuous purification system and method for high-purity graphite powder, wherein the purification system comprises a purification bin, a heater and a heat insulation felt are arranged outside the purification bin, an air supply assembly is arranged at the bottom of the purification bin, a porous graphite disc is arranged in the purification bin, a filter I is arranged at the top of the purification bin, a recoil air inlet valve I is arranged at the top of the purification bin, the feeding system comprises a feeding tank, a feeding assembly and an air inlet valve I, the discharging system comprises a discharging tank, a discharging assembly and an air inlet valve II, a vacuum system is arranged at the top of the purification bin, and the control system is used for controlling the operation of an integral device. According to the invention, continuous purification of graphite powder is realized, the feeding system, the purification system and the discharging system are cooperatively linked, a stable operation environment is continuously maintained by matching with a vacuum system, frequent shutdown and switching procedures are not needed, the operation intermittent time is greatly reduced, and the purification productivity is improved.

Inventors

  • WU ZHONGJU
  • WANG BING
  • MA XINXIN
  • FAN CHAO
  • JIA ZHIYONG
  • JI CHUNMING

Assignees

  • 山西中电科电子装备有限公司

Dates

Publication Date
20260505
Application Date
20260205

Claims (8)

  1. 1. A continuous purification system for high purity graphite powder, comprising: The purification system comprises a purification bin (1), a heater (2) and a heat preservation felt (3) are arranged outside the purification bin (1), an air supply assembly is arranged at the bottom of the purification bin (1), a porous graphite disc (37) is arranged in the purification bin (1), a filter I (4) is arranged at the top of the purification bin (1), and a recoil air inlet valve I (5) is arranged at the top of the purification bin (1); the feeding system comprises a feeding tank (6), a feeding assembly and an air inlet valve I (7), wherein the feeding assembly is used for feeding the feeding tank (6), the air inlet valve I (7) is used for supplying air to the feeding tank (6), a feeding pipeline (8) is arranged on the feeding tank (6), the feeding pipeline is connected with a feeding port of the purification bin (1), and a feeding air supplementing valve (9) and a feeding valve I (10) are arranged on the feeding pipeline (8); the discharging system comprises a discharging tank (11), a discharging assembly and an air inlet valve II (12), wherein the discharging assembly is used for extracting graphite powder from the discharging tank (11), the air inlet valve II (12) is used for supplying air to the discharging tank (11), a discharging pipeline (13) is arranged on the discharging tank (11), the discharging pipeline (13) is connected with the purifying bin (1), and a discharging air supplementing valve (14) and a discharging valve I (15) are arranged on the discharging pipeline (13); the vacuum system is arranged at the top of the purification bin (1) and is connected with the feeding tank (6) and the discharging tank (11) through vacuum pipelines I respectively; A control system (16), the control system (16) being configured to control overall device operation.
  2. 2. The continuous purification system of high purity graphite powder as recited in claim 1, wherein the gas supply assembly comprises: the funnel-shaped gas distribution plate (17), and the funnel-shaped gas distribution plate (17) is fixed at the bottom of the purification bin (1); A process gas inlet pipe (18), wherein the process gas inlet pipe (18) is fixed at the bottom of the funnel-shaped gas distribution disc (17), and a mass flowmeter (19) is arranged on the process gas inlet pipe (18); An inlet valve III (20), said inlet valve III (20) being mounted on said process gas inlet pipe (18); the other end of the process gas inlet pipe (18) is a process gas inlet, an argon gas inlet (21) is formed in the side wall of the process gas inlet pipe (18), and an argon gas inlet valve (22) is arranged on the argon gas inlet (21).
  3. 3. The continuous purification system of high-purity graphite powder, as set forth in claim 1, characterized in that the purification bin (1), the feeding tank (6) and the discharging tank (11) are provided with a feeding detector (23) and a vacuum gauge (24), the purification bin (1) is provided with a pyrometer (25), and the purification bin (1), the feeding tank (6) and the discharging tank (11) are provided with feeding observation windows (26) respectively.
  4. 4. The continuous purification system of high purity graphite powder according to claim 1, wherein the feeding assembly comprises a vacuum feeder (27), the output end of the vacuum feeder (27) is connected with the feeding tank (6), and a feeding valve II (28) is installed on the output end of the vacuum feeder (27).
  5. 5. The continuous purification system of high purity graphite powder according to claim 1, wherein the discharge assembly comprises a vacuum discharge machine (29), the input end of the vacuum discharge machine (29) is connected with the discharge tank (11), and a discharge valve II (30) is installed at the input end of the vacuum discharge machine (29).
  6. 6. The high-purity graphite powder continuous purification system according to claim 1, wherein the vacuum system comprises a vacuum pump (31), a pump port of the vacuum pump (31) is communicated with the top of the discharge tank (11) through a vacuum pipeline II, a gate valve I (32) and a pressure regulating valve (33) are installed on the vacuum pipeline II, and an output end of the vacuum pump (31) is connected with the feed tank (6) and the discharge tank (11) through the vacuum pipeline I.
  7. 7. The continuous purification system of high purity graphite powder according to claim 1, wherein a gate valve II (34), a filter II (35) and a recoil air inlet valve II (36) are installed on the vacuum pipeline I.
  8. 8. A continuous purification method of high-purity graphite powder, based on the continuous purification system of high-purity graphite powder as claimed in any one of claims 1 to 7, characterized by comprising the following steps: S1, starting self-checking of each system through a control system (16), checking connection tightness of a purification system, a feeding system, a discharging system and a vacuum system, confirming that a feeding valve I (10), a discharging valve I (15), a feeding air compensating valve (9), a discharging air compensating valve (14), an air inlet valve I (7), an air inlet valve II (12) and a backflushing air inlet valve I (5) are in a closed state, a filter I (4) is free of blockage, a porous graphite disc (37) is firmly installed, a heater (2), a heat preservation felt (3), an air supply assembly, a feeding assembly and a discharging assembly are normally operated, starting the vacuum system, setting a vacuum degree parameter through the control system (16), starting corresponding valves on a vacuum pipeline I, vacuumizing the feeding tank (6), the discharging tank (11) and a purification bin (1) respectively until the set vacuum degree is reached in each tank body and the purification bin (1), then starting the control system (16) to control the heater (2) of the purification system to operate at a low speed so as to keep the vacuum environment stable, and simultaneously, and using the control system (16) to perform purification bin (1) to perform purification by the heat preservation effect, the temperature in the purification bin (1) is continuously kept until the set vacuum degree is reached, and the temperature in the purification bin (1) is kept to be gradually higher by the heat preservation temperature, and the purification bin temperature is prevented from affecting the vacuum temperature in the purification bin (1; S2, starting a feeding component of a feeding system, adding graphite powder raw materials to be purified into a feeding tank (6) through the feeding component, closing a feeding port corresponding to the feeding component after feeding is completed, then opening an air inlet valve I (7), introducing inert gas into the feeding tank (6), adjusting the air inlet pressure to a set value, simultaneously opening a feeding air compensating valve (9) to carry out air compensating and pressure stabilizing on a feeding pipeline (8) so as to ensure smooth feeding process, opening the feeding valve I (10) through a control system (16) after confirming that the temperature and the vacuum degree in the purifying bin (1) reach the set values, feeding graphite powder to be purified in the feeding tank (6) enters a porous graphite disc (37) in the purifying bin (1) through the feeding pipeline (8) under the synergistic effect of the inert gas pressure and the vacuum suction, monitoring the feeding quantity in real time through the control system (16), ensuring that the graphite powder loading capacity on the porous graphite disc (37) meets the set requirement, and sequentially closing the feeding valve I (10), the feeding air compensating valve I (9) and the air inlet valve I (7), and simultaneously preparing the feeding pipeline (8) for vacuum treatment again through the vacuum system; S3, after feeding is finished, maintaining the set temperature and vacuum degree in the purification bin (1), starting an air supply assembly at the bottom of the purification bin (1), introducing process gas into the purification bin (1), uniformly blowing graphite powder by the process gas through pores of a porous graphite disc (37), carrying out chemical reaction with impurities in the graphite powder, changing the impurities in the graphite powder into gas, in the purification process, rising the impurity gas in the graphite powder to the top of the purification bin (1), removing the impurity gas through a filter I (4), wherein the filter I (4) can prevent graphite powder from being removed to the outside of the purification bin, if the filter I (4) is blocked in the filtration process, opening a backflushing air inlet valve I (5) through a control system (16), introducing backflushing gas into the filter I (4), closing the backflushing air inlet valve I (5) after the cleaning is finished, continuing to filter, and then continuously carrying out heating, heat preservation, vacuum maintenance and process gas inlet operation according to the set purification time, so as to ensure that the impurities in the graphite powder are fully volatilized and reacted, and the graphite powder is purified. S4, after purification is finished, a discharge valve I (15), a feeding air compensating valve (9) and an argon air inlet valve (22) are opened through a control system (16), purified high-purity graphite powder enters a discharge tank (11) from a purification bin (1) through a discharge pipeline (13) under the synergistic effect of inert gas pressure and vacuum suction, discharge quantity is monitored in real time through the control system (16) in the discharge process, smooth discharge is ensured, after discharge is finished, the discharge valve I (15), the feeding air compensating valve (9) and the argon air inlet valve (22) are sequentially closed, a discharge component of a discharge system is started, the high-purity graphite powder in the discharge tank (11) is extracted, collected and packaged, the discharge component is closed after discharge is finished, and the discharge tank (11) is vacuumized through a vacuum system to be ready for next discharge. S5, after the first discharging operation is finished and the vacuum pretreatment is finished by the feeding tank (6), repeating the operations of feeding, purifying and discharging, feeding, purifying and discharging into the purifying bin (1) again, realizing continuous purifying operation of graphite powder, monitoring the operation parameters of each system in real time by the control system (16) in the continuous purifying process, and if the parameters deviate, automatically adjusting the operation state of each component in time, ensuring the stable purifying process and the standard purifying effect, and simultaneously, periodically cleaning the filter I (4) in a backflushing way, periodically checking the tightness of each valve and pipeline, and periodically maintaining the feeding component, the discharging component and the heater (2) to avoid the influence of equipment faults on continuous operation. S6, after the purification operation is finished, the operation of the heater (2) is stopped through the control system (16), after the temperature in the purification bin (1) is reduced to the room temperature, the operation of all equipment of the vacuum system, the air supply assembly, the feeding assembly and the discharging assembly is stopped, all valves are closed, the purification bin (1), the feeding tank (6), the discharging tank (11), the porous graphite disc (37), the filter I (4) and all pipelines are cleaned, residual graphite powder and impurities are removed, equipment cleaning is ensured, after the cleaning is finished, the equipment state is checked, equipment maintenance records are prepared, and preparation is made for the next purification operation.

Description

Continuous purification system and method for high-purity graphite powder Technical Field The invention relates to the technical field of new energy negative electrode material graphite purification processing, in particular to a continuous purification system and method for high-purity graphite powder. Background The great development of new energy battery industry in China is a strategic decision with profound significance. The method has the advantages that the method has high dependence on petroleum in China, the petroleum consumption in the traffic field can be greatly reduced by developing the electric automobile, the external dependence is reduced, the autonomous energy control is realized, and the method has larger speaking right in the formulation of global future technical standards and market rules and takes the future economy and technical high points through the leading of new energy battery technology. In the new energy battery industry, natural crystalline flake graphite plays a key role in the field of new energy battery cathode materials by virtue of a unique layered structure, high theoretical capacity and rich resource reserve. The purity of the new energy battery negative electrode graphite powder reaches 99.95%, but the purity of graphite obtained by chemical flotation from graphite ore is only 94% -95%, and if the purity of the negative electrode material reaches 99.95%, the natural graphite powder needs to be purified in high purity, and the common high-purity purification methods at present are an alkali acid method, a hydrofluoric acid method, a chloridizing roasting method, a high-temperature method and a physical and chemical purification pure method. The alkaline acid method comprises the steps of mixing graphite with sodium hydroxide, reacting at 650 ℃ to generate an insoluble oxyhydrogen compound and a partially soluble product, washing with water to remove partial impurities, mixing the product after alkaline melting with hydrochloric acid solution with a certain concentration, reacting at 60-90 ℃ to change the impurities into soluble chlorides, washing with water, and finally drying to obtain the high-purity graphite product. The hydrofluoric acid process includes the reaction of the impurity in the raw ore with hydrofluoric acid to produce water soluble fluoride and silicofluoric acid, and washing with water to eliminate the impurity in the raw ore to obtain high grade graphite. The process has high impurity removing efficiency, high product quality, small influence on the performance of graphite products and low energy consumption. However, hydrofluoric acid has extremely toxic and strong corrosiveness, a strict safety wastewater treatment system is required in the production process, and the environmental protection investment is large. The chloridizing roasting method is that graphite is mixed with a certain amount of reducing agent, roasted at 1000 ℃ in a specific atmosphere, and then chlorine is introduced to react, so that valuable metals in the material are converted into gas phase or condensed phase chlorides and complexes with lower melting point to escape, and the purpose of purifying graphite is achieved by separating the materials from the rest components. The method has the advantages of low energy consumption, high purification efficiency, high recovery rate and low cost. However, chlorine is toxic and has serious corrosiveness to metal products, and if leakage occurs, the environment is seriously polluted. The high temperature purification process is to heat graphite to over 2700 deg.c to gasify and escape the impurity in graphite to reach the aim of purification. The process can obtain high-purity graphite products, but high-temperature purification equipment is expensive, power consumption is high, production scale is limited, and yield is low. The materialized purification method is characterized in that a graphite product to be purified is placed in a vacuum furnace for heating, the vacuum degree in the furnace is increased, impurities in the graphite product automatically volatilize when reaching the saturated vapor pressure, and oxides with high melting boiling point in the graphite impurities are converted into halides with low melting point through halogen gas, so that the purification effect is achieved. The main purification method of the natural graphite anode material in the industry at present is an alkali acid method, the technology of the method is mature, the operation is simple and convenient, the production efficiency is high, but the generated waste liquid is difficult to treat, and if the treatment does not reach the standard, the environmental protection pressure can be faced. Based on the technical problems, the invention provides a continuous purification system and method for high-purity graphite powder. Disclosure of Invention The invention aims to provide a continuous purification system and method for high-purity graphite powder, whi