WO2017048027A1 - Method for preparing graphene by using eutectic graphite - Google Patents

Method for preparing graphene by using eutectic graphite Download PDF

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WO2017048027A1
WO2017048027A1 PCT/KR2016/010286 KR2016010286W WO2017048027A1 WO 2017048027 A1 WO2017048027 A1 WO 2017048027A1 KR 2016010286 W KR2016010286 W KR 2016010286W WO 2017048027 A1 WO2017048027 A1 WO 2017048027A1
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graphite
graphene
mixture
graphene manufacturing
acid
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French (fr)
Korean (ko)
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오철
이형윤
장강일
이현우
한동윤
김미선
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일진다이아몬드(주)
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
    • B01J3/06—Processes using ultra-high pressure, e.g. for the formation of diamonds; Apparatus therefor, e.g. moulds or dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/10—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing sonic or ultrasonic vibrations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis

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  • the present invention relates to a graphene manufacturing method using a process graphite, and more particularly, to a graphene manufacturing method using a process graphite that can be recycled as a raw material for the production of graphene, a process by-product produced during diamond manufacturing. will be.
  • Graphene is a two-dimensional material made of carbon atoms and has a honeycomb structure, and the types of graphene include single-layer graphene, two-layer graphene, and multi-layer graphene. Graphene or Graphite).
  • the thickness of the single layer graphene is very thin, about 0.34 nm, which is one carbon atom, but when the graphene sheet is overlapped to a thickness of mm, the strength is sufficient to support a two-ton car.
  • graphene is transparent and has a higher thermal conductivity than silver when absorbing only 2.3% of light, and moves electrons as if they have no mass, so that the flow of electricity is faster than that of conventional semiconductors. Be in the spotlight.
  • graphene is the most outstanding material among various materials with various characteristics such as strength, thermal conductivity, and electron mobility. It is applied to various fields such as display, secondary battery, solar cell, automobile, and lighting, and is strategic to drive the growth of related industries. It is recognized as a core material.
  • the method for preparing graphene includes a method of separating a layer of graphene from graphite crystals, a chemical vapor deposition method for synthesizing graphene using a transition metal that adsorbs carbon well at high temperature as a catalyst layer, and being adsorbed or contained in the crystal at high temperature.
  • a chemical vapor deposition method for synthesizing graphene using a transition metal that adsorbs carbon well at high temperature as a catalyst layer and being adsorbed or contained in the crystal at high temperature.
  • the chemical exfoliation method of oxidizing graphite and separating it from the solution phase and then reducing it is easy for mass production and chemical modification, which allows hybridization with other materials. Because of its merits, much research is ongoing.
  • Chemical exfoliation can be simply performed by inserting the graphene interlayer oxygen functional group in the graphite oxide manufacturing process and then by ultrasonic grinding.
  • the explosive risk may be relatively small in the case of graphene production through chemical exfoliation at the laboratory level, but the process at the factory level for mass production consumes enormous cost and effort to control the explosion hazard. In the event of an accident, extreme damage is expected to be unpredictable.
  • graphite used as a raw material in the production of graphene is used for electrodes such as pencil cores, crucibles, electric furnaces, arcs, and the like as a lubricating material, and is also used when manufacturing synthetic diamond.
  • Synthetic diamond is used in the field of precision electronics and semiconductors as the demand for precision materials such as printed circuit board (PCB), light emitting diode (LED), and photovoltaic industry substrates is increasing.
  • industrial diamond is used as a basic abrasive for precision processing of various machinery, and as a cutting material and processing material of high strength materials, the value as a strategic material is becoming increasingly important.
  • particles having a particle size of less than 104 ⁇ m are referred to as industrial powder diamond, and such powdered synthetic diamond is manufactured by using a high temperature and high pressure process.
  • Synthetic diamond high temperature high pressure process is produced by sintering graphite and metals such as cobalt, nickel, iron at 1500 °C and 50,000 atm, and after sintering and classifying diamond and precious metals, the process graphite remains as a process by-product. At this time, the process graphite generated is disposed of, and thus, environmental pollution and cost loss are problematic.
  • the present invention provides a method for producing graphene using process graphite which can recycle process graphite, which is a by-product of the discarded diamond manufacturing process, to a high value-added industrial material.
  • the present invention provides a graphene manufacturing method using a process graphite comprising a unit process that can reduce the explosion risk during insertion of the graphene interlayer oxygen functional group.
  • the present invention provides a method for producing graphene using process graphite, which is environmentally friendly and cost-effective by using process graphite which is a by-product discarded in the diamond manufacturing process.
  • Graphene manufacturing method using a process graphite comprises a first step of producing a sintered body comprising diamond and unreacted graphite by sintering a mixed powder containing a metal and graphite; A second step of immersing the sintered body in an aqueous strong acid solution and electrolyzing the mixture into a mixture containing diamond and graphite; A third step of stirring by adding an aqueous potassium permanganate (KMnO4) solution to the mixture; A fourth step of peeling the graphite in the mixture; A fifth step of recovering the exfoliated graphene oxide; And a sixth step of reducing the recovered graphene oxide.
  • aqueous potassium permanganate aqueous potassium permanganate
  • an acid removal for partially removing the strong acid such that the weight ratio of the strong acid remaining without absorbing the graphite to the weight of the total strong acid included in the mixture is within 5% It may further comprise a step.
  • the graphite in the mixture may be in the form of a slurry.
  • the method may further include a recovery step of recovering diamond from the mixture after the second step.
  • the recovery step may further recover the precious metal.
  • after the recovery step may further comprise the step of purifying the graphite in the mixture.
  • the method may further include adding sulfuric acid (H 2 SO 4 ) having a concentration of 5% to the byproduct in the third step.
  • sulfuric acid H 2 SO 4
  • sulfuric acid H 2 SO 4
  • the sulfuric acid may be added to the by-product in a state mixed in the aqueous potassium permanganate solution.
  • the aqueous potassium permanganate (KMnO 4 ) solution may further include sodium nitrate (NaNO 3 ).
  • the acid introduced in the second step may include at least one of sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ) and hydrochloric acid (HCl).
  • sulfuric acid H 2 SO 4
  • phosphoric acid H 3 PO 4
  • nitric acid HNO 3
  • hydrochloric acid HCl
  • the metal powder may include at least one of iron, nickel and cobalt.
  • the sintering may be performed at a temperature of 500 to 3000.
  • the sintering may be performed at a pressure of 40000 atm to 60000 atm.
  • the sintering may be performed for 40 to 80 minutes.
  • the fourth step may be performed by heat treatment or ultrasonic irradiation.
  • At least one reducing agent of hydrazine, sodium hydride, hydroquinone, sodium borohydride, ascorbic acid and glucose is added. It can be performed by.
  • the process graphite which is a by-product discarded after the diamond manufacturing process, as a raw material of graphene, it is possible to reduce costs in the manufacture of graphene, and to reduce additional costs such as waste treatment costs for discarding process graphite. It is effective.
  • FIG. 1 is a flow chart showing a graphene manufacturing method according to an embodiment of the present invention.
  • FIG. 2 is a flow chart showing a graphene manufacturing method according to another embodiment.
  • Graphene manufacturing method using a process graphite comprises a first step of producing a sintered body comprising diamond and unreacted graphite by sintering a mixed powder containing a metal and graphite; A second step of immersing the sintered body in an aqueous strong acid solution and electrolyzing the mixture into a mixture containing diamond and graphite; A third step of stirring by adding an aqueous potassium permanganate (KMnO4) solution to the mixture; A fourth step of peeling the graphite in the mixture; A fifth step of recovering the exfoliated graphene oxide; And a sixth step of reducing the recovered graphene oxide.
  • aqueous potassium permanganate aqueous potassium permanganate
  • FIG. 1 is a flow chart showing a graphene manufacturing method according to an embodiment of the present invention.
  • Graphene manufacturing method is a first step (S100) of producing a sintered body including diamond and unreacted graphite by sintering metal powder and graphite powder, the sintered body is immersed in an acid solution and electrolyzed to diamond And a second step (S200) of converting to a mixture containing graphite, a third step (S300) of stirring by adding an aqueous solution of potassium permanganate (KMnO 4 ) to the mixture, and a fourth step (S400) of removing process graphite in the mixture. ), A fifth step (S500) of recovering the exfoliated graphene oxide, and a sixth step (S600) of reducing the recovered graphene oxide.
  • S100 first step of producing a sintered body including diamond and unreacted graphite by sintering metal powder and graphite powder, the sintered body is immersed in an acid solution and electrolyzed to diamond
  • a second step (S200) of converting to a mixture containing graphite
  • the metal powder may include at least one of iron, nickel, and cobalt as a catalyst.
  • Graphite, iron, nickel, and cobalt powder are put in a cell of a certain size and sintered at high temperature and high pressure.
  • the sintering may be performed for 40 to 80 minutes at a temperature of 500 ⁇ 3000 °C, pressure 40,000 ⁇ 60,000 atm.
  • the sintered body is immersed in an acid solution and electrolyzed.
  • the sintered body described above is formed in a state in which diamond, unreacted graphite, a catalyst metal, and the like are mixed.
  • the sintered body is difficult to be separated into diamond, graphite, and catalytic metal by physical methods. Therefore, in the second step, the sintered body is separated into diamond, graphite, and catalytic metal, respectively, and converted into a physically easy mixture. .
  • only 10% of the initial graphite input is present as diamond, and the remaining 90% unreacted process graphite and metal powder are present in the mixture.
  • graphite intercalation occurred under high temperature and high pressure treatment, which acts in an advantageous form for the graphene oxide exfoliation process.
  • the acid solution used at this time may be any one of sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ) and hydrochloric acid (HCl).
  • sulfuric acid (H 2 SO 4 ) it is preferable to use sulfuric acid (H 2 SO 4 ), but is not necessarily limited thereto.
  • the third step (S300) in the acid treatment of step a graphite slurry of potassium permanganate in (KMnO 4) input, or potassium permanganate (KMnO 4) and the aqueous solution added to the acid treatment of the process of graphite slurry in graphene oxygen functional group in the interlayer of an aqueous solution Form / Insert.
  • concentration of the potassium permanganate (KMnO 4 ) aqueous solution to the graphite oxide slurry can be adjusted the reaction rate with sulfuric acid (H 2 SO 4 ).
  • potassium permanganate (KMnO 4) forming an aqueous solution were charged into a graphite oxide slurry, or by injecting the graphite oxide slurry in potassium permanganate (KMnO 4) aqueous solution of the process according to the third step in the exclusion or eliminate the danger of an explosion condition You can proceed.
  • potassium permanganate (KMnO 4 ) aqueous solution may further include sodium nitrate.
  • the method may further include adding 5% sulfuric acid (H 2 SO 4 ) as an additive (reaction activation).
  • 5% sulfuric acid (H 2 SO 4 ) is added as an additive and potassium permanganate (KMnO 4 ) aqueous solution is added, graphene interlayer oxygen functional group insertion can be made more smoothly and stably. Speed control is also possible.
  • the graphene is peeled off by irradiating heat treatment or ultrasonic waves to the acid-treated waste process graphite.
  • graphene oxide itself may be used as it is, it is necessary to reduce graphene oxide through a physicochemical method in order to utilize the original electrical and physical properties of graphene.
  • a high temperature heat treatment process using a hydrazine-based reducing agent and / or hydrogen to reduce the graphene oxide.
  • the graphene manufacturing method according to the present invention can be applied to a variety of known reduction methods, there is no particular limitation.
  • a hydrazine system As the reagent used in the chemical reduction method, a hydrazine system is mainly used.
  • hydrazine or sodium hydride When hydrazine or sodium hydride is used as a reducing agent, it is known to effectively remove epoxy groups or hydroxyl groups on the graphene surface but not carbonyl or carboxyl groups located at the edges.
  • Such residual functional groups can be removed by sulfuric acid treatment or high temperature heat treatment. Thermal reduction occurs at temperatures above 200 degrees in an inert gas or reducing gas environment. Desorption of oxygen in graphene oxide occurs rapidly at high temperatures above 200 degrees and gradually occurs at temperatures below 200 degrees.
  • Hydroquinone and sodium borohydride have been studied as alternative materials for hydrazine-based reducing agents.
  • reducing agents such as ascorbic acid (glucose), glucose (glucose) has been reported.
  • Other organic solvents such as basic aqueous solution, distilled water, dimethylformamide (DMF), methylacetamide, and n-methylpyrrolidinone (NMP) induce deoxidation reactions through normal heating or by using microwaves A method of reducing in a short time of about 15 minutes has been studied.
  • the reduction of graphene oxide may be performed in a basic solution, a supercritical aqueous solution, or even a solvent, and therefore, care should be taken when analyzing the chemical structure of graphene oxide.
  • it can be effectively reduced by the hydrogen plasma treatment, there are other electrochemical reduction, photocatalyst reduction, flash conversion (Flash conversion) method and the like.
  • FIG. 2 is a flowchart illustrating a graphene manufacturing method using eutectic graphite according to another embodiment.
  • graphite powder is added to an aqueous solution of sulfuric acid (H 2 SO 4 ) to disperse the graphite oxide powder in an aqueous solution to form a graphite oxide thin film plate, and then potassium permanganate (KMnO 4 ) powder is gradually added to the graphene.
  • An oxygen functional group was inserted between the pin layers.
  • this method uses potassium permanganate (KMnO 4 ) powder to prevent explosions due to rapid exothermic reaction with sulfuric acid in the process of inserting oxygen functional groups between graphene layers to prevent rapid temperature rise.
  • the graphene must be prepared by the method.
  • this method may be easy to manage in small-scale manufacturing at the laboratory level, but if the mass production is carried out at the factory level, the risk of explosion may exist and the safety of workers may be threatened. This can occur enormously and requires improved management of explosion risk.
  • Graphite in the mixture is present in the slurry that has absorbed sulfuric acid (H 2 SO 4) in step 2. Therefore, it may be used only through the step of filtration or partial removal of surplus sulfuric acid remaining in the by-product, without undergoing a process of removing acid from the graphite through a separate washing or drying process. Sulfuric acid present in the mixture is further removed to minimize the residual acid solution (S600) by removing some or all of the sulfuric acid (H 2 SO 4 ) not absorbed in the process graphite to the total weight of sulfuric acid in the mixture to be within 5%. It may include.
  • the method includes controlling the amount of surplus sulfuric acid in the byproduct to be within 5%, and when the remaining sulfuric acid (H 2 SO 4 ) solution is minimized, the solution of potassium permanganate (KMnO 4 ) in the third step (S300). If it is injected, the temperature can be easily controlled and the risk of explosion can be reduced. That is, the amount of sulfuric acid and potassium permanganate instantaneous contact can be minimized, and the proportion of sulfuric acid (H 2 SO 4 ) and potassium permanganate (KMnO 4 ) is proportional to the time when the aqueous solution of potassium permanganate (KMnO 4 ) penetrates between the plate-like structures of graphite.
  • the sintered compact is immersed in an aqueous sulfuric acid solution and separated by electrolysis, thereby allowing the diamond, graphite, and catalytic metals to be easily recovered or separated from each other through a physical method. Convert
  • the process of recovering diamond or the like from the mixture converted through the second step S200 may be performed at any step after the second step S200. That is, it may be possible to recover the diamond at any stage after the second step (S200), or to further collect and recover precious metals, or to separate and refine the process graphite from the mixture (S900). That is, the graphite oxide is prepared in the form of a brown viscous slurry, and is formed of graphite oxide, exfoliated thin film oxide plate, unoxidized graphite chips and residues of oxidizing agent.
  • the graphite oxide may improve the quality and yield of graphene by removing impurities that sink through the purification process (S900) through centrifugation and selectively filtering graphite oxide to obtain purified graphite oxide.
  • the process of separating the process graphite from the mixture is applicable variously known filtration methods such as gravity filtration, pressure filtration, reduced pressure filtration, centrifugal filtration, osmotic filtration, there is no particular limitation on the filtration method.
  • H 2 O 2 treatment S700
  • H 2 O 2 hydrogen peroxide
  • the graphite powder and the metal powder iron, nickel, cobalt powder is put in a cell of a constant size, and sintered for 60 minutes under a temperature of 1500 °C and 50,000 atm pressure.
  • the sintered product is electrolyzed by dipping in dilute sulfuric acid. After electrolysis, diamond and unreacted byproducts are separated by gravity filtration in the converted mixture.
  • an acid solution for immersing the metal powder and the graphite sintered material is preferably sulfuric acid, but at least one of phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ), and hydrochloric acid may be used. It is possible.
  • a potassium permanganate (KMnO 4 ) aqueous solution is added to the graphite slurry passed through the second step (S200), followed by stirring.
  • Potassium permanganate (KMnO 4 ) is preferably used as an aqueous solution of potassium permanganate (KMnO 4 ) rather than powder particles, it is added to the process graphite in the form of acid-treated slurry and stirred.
  • the graphene manufacturing method using the graphite manufacturing process Busan graphite according to the present embodiment is suitable for mass production of graphene.
  • Graphite oxide is prepared in the form of a brown viscous slurry and is formed of graphite oxide, exfoliated thin film oxide plates, unoxidized graphite pieces and residues of oxidants.
  • the graphite oxide may be subjected to purification through centrifugation, at which time it is possible to remove the sinking impurities and selectively filter the suspended graphite oxide.
  • the process graphite is ultrasonically pulverized and separated into graphite oxide.
  • the purified graphite oxide is dispersed in a basic aqueous solution or an organic solvent through ultrasonic grinding, and at this time, it is exfoliated in the form of graphene oxide.
  • Graphene oxide having a more uniform monolayer and area is obtained through a density gradient-centrifugation process after ultrasonic grinding.
  • the graphene oxide is peeled off is reduced. It is also possible to use graphene oxide for specific applications, but graphene oxide is a form of graphene that has lost its electrical and thermal properties. Therefore, in order to recover the lost electrical and thermal properties of graphene, the graphene oxide is reduced to finally form a reduced graphene.
  • hydrazine or the like may be used as a reducing agent for reducing graphite oxide.

Abstract

The present invention relates to a method for preparing graphene by using eutectic graphite. According to the present invention, the method for preparing graphene by using eutectic graphite comprises: a first step of preparing a sintered body comprising diamond and unreacted graphite, by sintering a mixture powder comprising a metal and graphite; a second step of converting, by dipping the sintered body in a strong acid aqueous solution and carrying out electrolysis on the same into a mixture comprising diamond and graphite; a third step of injecting a potassium permanganate (KMnO4) aqueous solution into the mixture, and stirring the same; a fourth step of stripping graphite within the mixture; a fifth step of recovering stripped graphene oxide; and a sixth step of reducing the stripped graphene oxide. According to the present invention, since eutectic graphite, which is a by-product to be disposed of after the process for preparing diamond, is recycled so as to be used as a raw material for graphene, graphene preparation costs can be reduced, and there is also an effect of enabling additional costs for disposing eutectic graphite to be reduced.

Description

공정흑연을 이용한 그래핀 제조방법Graphene manufacturing method using eutectic graphite
본 발명은 공정흑연을 이용한 그래핀 제조방법에 관한 것으로서, 보다 상세하게는 다이아몬드 제조시 발생되는 부산물인 공정흑연을 그래핀 제조를 위한 원료로 재활용할 수 있는 공정흑연을 이용한 그래핀 제조방법에 관한 것이다.The present invention relates to a graphene manufacturing method using a process graphite, and more particularly, to a graphene manufacturing method using a process graphite that can be recycled as a raw material for the production of graphene, a process by-product produced during diamond manufacturing. will be.
그래핀은 탄소 원자로 만들어진 2차원 물질로 벌집 모양 구조를 가지고 있으며, 그래핀의 종류로는 한층 그래핀(Single-Layer Graphene), 두층 그래핀(Two-Layer Graphene) 및 다층 그래핀(Multi-Layer Graphene 또는 Graphite) 등으로 나눌 수 있다. 단층 그래핀의 두께는 탄소원자 1개분인 약 0.34nm로 대단히 얇으나, 그래핀 시트를 겹쳐서 ㎜ 수준의 두께로 만들면 2톤짜리 자동차를 지지할 수 있는 강도가 발생할 정도로 매우 단단하다. 또한 그래핀은 투명하며 빛의 2.3%만을 흡수해도 상온에서 은보다 열전도성이 높으며, 전자가 마치 질량이 없는 것처럼 움직여 기존 반도체보다 전기의 흐름이 빨라질 수 있어 실리콘 기판을 대체할 수 있는 차세대 재료로 각광받고 있다. Graphene is a two-dimensional material made of carbon atoms and has a honeycomb structure, and the types of graphene include single-layer graphene, two-layer graphene, and multi-layer graphene. Graphene or Graphite). The thickness of the single layer graphene is very thin, about 0.34 nm, which is one carbon atom, but when the graphene sheet is overlapped to a thickness of ㎜, the strength is sufficient to support a two-ton car. In addition, graphene is transparent and has a higher thermal conductivity than silver when absorbing only 2.3% of light, and moves electrons as if they have no mass, so that the flow of electricity is faster than that of conventional semiconductors. Be in the spotlight.
이처럼, 그래핀은 강도, 열전도율, 전자이동도 등 여러 가지 특징이 현존하는 물질 중 가장 뛰어난 소재로 디스플레이, 이차전지, 태양전지, 자동차 및 조명 등 다양한 분야에 응용되어 관련 산업의 성장을 견인할 전략적 핵심소재로 인정받고 있다. As such, graphene is the most outstanding material among various materials with various characteristics such as strength, thermal conductivity, and electron mobility. It is applied to various fields such as display, secondary battery, solar cell, automobile, and lighting, and is strategic to drive the growth of related industries. It is recognized as a core material.
그래핀(graphene)을 제조하는 방법으로는 기계적 박리법, 화학적 박리법, 비산화 박리법, 화학증기증착법, 에피택시법 등 다양한 방법의 그래핀(graphene) 제조기술이 현재 사용되고 있다. 그래핀을 제조하는 방법에는 흑연결정으로부터 그래핀 한층을 분리하는 방법, 고온에서 탄소를 잘 흡착하는 전이금속을 촉매층으로 이용하여 그래핀을 합성하는 화학기상증착법 및 고온에서 결정에 흡착되어 있거나 포함되어 있던 탄소가 표면의 결을 따라 성장하는 에피성장법이 있으며, 특히 흑연을 산화시켜 용액상에서 분리한 후 환원시키는 화학적 박리법은 대량생산의 가능성과 화학적 개질이 용이하여 다른 소재와의 하이브리드가 가능하다는 장점 때문에 많은 연구가 진행중이다.As a method for producing graphene, graphene production techniques of various methods, such as mechanical peeling, chemical peeling, non-oxidative peeling, chemical vapor deposition, and epitaxy, are currently used. The method for preparing graphene includes a method of separating a layer of graphene from graphite crystals, a chemical vapor deposition method for synthesizing graphene using a transition metal that adsorbs carbon well at high temperature as a catalyst layer, and being adsorbed or contained in the crystal at high temperature. There is an epitaxial growth method in which carbon has grown along the surface texture. Especially, the chemical exfoliation method of oxidizing graphite and separating it from the solution phase and then reducing it is easy for mass production and chemical modification, which allows hybridization with other materials. Because of its merits, much research is ongoing.
화학적 박리는 산화흑연 제조 과정에서 그래핀 층간 산소 관능기를 삽입한 후 초음파 분쇄를 통하여 간단히 이루어질 수 있다. 다만, 그래핀 층간에 산소 관능기를 삽입하는 과정에서 고열의 발생으로 인한 폭발 위험성이 상존하게 된다. 이러한 화학적 박리를 통한 그래핀 제조가 실험실 단위에서 이루어지는 경우에는 폭발 위험성이 상대적으로 작게 평가될 수 있지만, 대량 생산을 위한 공장 단위에서의 공정에서는 폭발 위험성의 제거를 위한 제어에 막대한 비용 및 노력이 소모되는 문제가 발생하며, 한번 사고가 발생하는 경우에는 그 규모를 예측할 수 없는 극심한 피해가 예상된다.Chemical exfoliation can be simply performed by inserting the graphene interlayer oxygen functional group in the graphite oxide manufacturing process and then by ultrasonic grinding. However, there is a risk of explosion due to the generation of high heat in the process of inserting oxygen functional groups between graphene layers. The explosive risk may be relatively small in the case of graphene production through chemical exfoliation at the laboratory level, but the process at the factory level for mass production consumes enormous cost and effort to control the explosion hazard. In the event of an accident, extreme damage is expected to be unpredictable.
한편, 그래핀 제조에서 원료로 사용되는 흑연은 연필심, 도가니, 전기로, 아크 등의 전극에 사용되고, 활마재로 사용하며 합성 다이아몬드를 제조할 때에도 사용된다. 합성 다이아몬드는 기존의 기간산업 분야용도 외에도 최근에는 인쇄회로기판(PCB), 발광다이오드(LED), 태양광산업용 기판 등 정밀 소재 가공 수요가 늘어나면서 정밀전자, 반도체 분야의 활용도 크게 늘고 있다. 또한, 공업용 다이아몬드는 각종 기계류의 정밀 가공의 기본 연마제로써 사용되며 그 외 고강도 소재의 절삭재료, 가공재료로 활용되어 전략소재로서의 가치가 점점 중요해지고 있다.On the other hand, graphite used as a raw material in the production of graphene is used for electrodes such as pencil cores, crucibles, electric furnaces, arcs, and the like as a lubricating material, and is also used when manufacturing synthetic diamond. Synthetic diamond is used in the field of precision electronics and semiconductors as the demand for precision materials such as printed circuit board (PCB), light emitting diode (LED), and photovoltaic industry substrates is increasing. In addition, industrial diamond is used as a basic abrasive for precision processing of various machinery, and as a cutting material and processing material of high strength materials, the value as a strategic material is becoming increasingly important.
일반적으로 입도가 104 μm보다 작은 것을 공업용 분말형 다이아몬드라고 하며, 이러한 분말형 합성다이아몬드는 고온고압공정을 이용하여 제조된다. 합성 다이아몬드 고온고압공정은 흑연 및 코발트, 니켈, 철 등의 금속을 섭씨 1500℃ 및 5만기압 하에서 소결시켜 제조하며, 소결 후 다이아몬드 및 귀금속을 분류하고 나면 공정흑연이 공정 부산물로써 남게 된다. 이때 발생되는 공정흑연은 폐기처리되고 있으며, 이에따른 환경오염 및 비용손실이 문제가 되고 있는 실정이다.In general, particles having a particle size of less than 104 μm are referred to as industrial powder diamond, and such powdered synthetic diamond is manufactured by using a high temperature and high pressure process. Synthetic diamond high temperature high pressure process is produced by sintering graphite and metals such as cobalt, nickel, iron at 1500 ℃ and 50,000 atm, and after sintering and classifying diamond and precious metals, the process graphite remains as a process by-product. At this time, the process graphite generated is disposed of, and thus, environmental pollution and cost loss are problematic.
본 발명은 폐기되는 다이아몬드 제조 공정의 부산물인 공정흑연을 고부가가치의 산업소재로 재활용할 수 있는 공정흑연을 이용한 그래핀 제조방법을 제공한다.The present invention provides a method for producing graphene using process graphite which can recycle process graphite, which is a by-product of the discarded diamond manufacturing process, to a high value-added industrial material.
또한 본 발명은 그래핀 층간 산소 관능기의 삽입 과정에서 폭발 위험성을 줄일 수 있는 단위 공정들을 포함하는 공정흑연을 이용한 그래핀 제조방법을 제공한다.In another aspect, the present invention provides a graphene manufacturing method using a process graphite comprising a unit process that can reduce the explosion risk during insertion of the graphene interlayer oxygen functional group.
또한 본 발명은 다이아몬드 제조 공정에서 폐기되는 부산물인 공정흑연을 사용함으로써 친환경적이며 비용절감 효과가 있는 공정흑연을 이용한 그래핀 제조방법을 제공한다.In addition, the present invention provides a method for producing graphene using process graphite, which is environmentally friendly and cost-effective by using process graphite which is a by-product discarded in the diamond manufacturing process.
본 발명에 따른 공정흑연을 이용한 그래핀 제조방법은 금속 및 흑연을 포함하는 혼합 분말을 소결하여 다이아몬드 및 미반응 흑연을 포함하는 소결체를 제조하는 제1단계; 상기 소결체를 강산 수용액에 침지하고 전기분해하여 다이아몬드 및 흑연을 포함하는 혼합물로 변환하는 제2단계; 상기 혼합물에 과망간산칼륨(KMnO4) 수용액을 투입하여 교반하는 제3단계; 상기 혼합물 내의 흑연을 박리시키는 제4단계; 상기 박리된 산화그래핀을 회수하는 제 5단계; 및 상기 회수된 산화 그래핀을 환원시키는 제 6단계;를 포함한다.Graphene manufacturing method using a process graphite according to the present invention comprises a first step of producing a sintered body comprising diamond and unreacted graphite by sintering a mixed powder containing a metal and graphite; A second step of immersing the sintered body in an aqueous strong acid solution and electrolyzing the mixture into a mixture containing diamond and graphite; A third step of stirring by adding an aqueous potassium permanganate (KMnO4) solution to the mixture; A fourth step of peeling the graphite in the mixture; A fifth step of recovering the exfoliated graphene oxide; And a sixth step of reducing the recovered graphene oxide.
또한 상기 제2단계 이후 및 상기 제3단계 이전에, 상기 혼합물 내에 포함되는 전체 강산의 중량 대비 상기 흑연에 흡수되지 않고 잔존하는 강산의 중량 비율이 5% 이내가 되도록 상기 강산을 일부 제거하는 산제거 단계를 더 포함할 수 있다.In addition, after the second step and before the third step, an acid removal for partially removing the strong acid such that the weight ratio of the strong acid remaining without absorbing the graphite to the weight of the total strong acid included in the mixture is within 5% It may further comprise a step.
또한 상기 혼합물 내의 흑연은 슬러리 형태일 수 있다.In addition, the graphite in the mixture may be in the form of a slurry.
또한 상기 제2단계 이후 상기 혼합물로부터 다이아몬드를 회수하는 회수단계를 더 포함할 수 있다.The method may further include a recovery step of recovering diamond from the mixture after the second step.
또한 상기 회수단계에서는 귀금속을 더 회수할 수 있다.In addition, the recovery step may further recover the precious metal.
또한 상기 회수 단계 이후 상기 혼합물 내의 흑연을 정제시키는 단계를 더 포함할 수 있다.In addition, after the recovery step may further comprise the step of purifying the graphite in the mixture.
또한 상기 제3단계에서 상기 부산물에 농도 5%의 황산(H2SO4)을 더 투입하는 단계를 더 포함할 수 있다.The method may further include adding sulfuric acid (H 2 SO 4 ) having a concentration of 5% to the byproduct in the third step.
또한 상기 황산(H2SO4)은 상기 과망간산칼륨 수용액에 혼합된 상태로 상기 부산물에 투입될 수 있다.In addition, the sulfuric acid (H 2 SO 4 ) may be added to the by-product in a state mixed in the aqueous potassium permanganate solution.
또한 상기 제3단계에서 상기 과망간산칼륨(KMnO4)수용액은 질산나트륨(NaNO3)을 더 포함할 수 있다.In addition, in the third step, the aqueous potassium permanganate (KMnO 4 ) solution may further include sodium nitrate (NaNO 3 ).
또한 상기 제2단계에서 투입되는 산(acid)은 황산(H2SO4), 인산(H3PO4), 질산(HNO3) 및 염산(HCl) 중 적어도 어느 하나를 포함할 수 있다.In addition, the acid introduced in the second step may include at least one of sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ) and hydrochloric acid (HCl).
또한 상기 금속분말은 철, 니켈 및 코발트 중 적어도 어느 하나를 포함할 수 있다.In addition, the metal powder may include at least one of iron, nickel and cobalt.
또한 상기 제1단계에서 상기 소결은 500 내지 3000의 온도에서 수행될 수 있다.In addition, in the first step, the sintering may be performed at a temperature of 500 to 3000.
또한 상기 제1단계에서 상기 소결은 40000atm 내지 60000atm의 압력에서 수행될 수 있다.In the first step, the sintering may be performed at a pressure of 40000 atm to 60000 atm.
또한 상기 제1단계에서 상기 소결은 40 내지 80분 동안 수행될 수 있다.In addition, in the first step, the sintering may be performed for 40 to 80 minutes.
또한 상기 제4단계는 열처리 또는 초음파의 조사를 통하여 수행될 수 있다.In addition, the fourth step may be performed by heat treatment or ultrasonic irradiation.
또한 상기 제 6단계는 하이드리진(hydrazine), 나트륨 하이드라이드, 하이드로퀴논(hydroquinone), 나트륨 보로하이드라이드(sodium borohydride), 아스코빅산(ascorbic acid) 및 글루코스(glucose) 중 적어도 어느 하나의 환원제의 투입에 의하여 수행될 수 있다.In the sixth step, at least one reducing agent of hydrazine, sodium hydride, hydroquinone, sodium borohydride, ascorbic acid and glucose is added. It can be performed by.
본 발명에 따르면 다이아몬드 제조 공정 후 폐기되는 부산물인 공정흑연을 재활용하여 그래핀의 원료로 사용함으로써 그래핀 제조 시 비용을 절감할 수 있으며, 공정흑연을 폐기하기 위한 폐기물 처리 비용 등의 추가비용을 절감하는 효과가 있다.According to the present invention, by recycling the process graphite, which is a by-product discarded after the diamond manufacturing process, as a raw material of graphene, it is possible to reduce costs in the manufacture of graphene, and to reduce additional costs such as waste treatment costs for discarding process graphite. It is effective.
또한, 본 발명에 따르면 다이아몬드 제조 공정 후 폐기되는 부산물인 공정흑연을 재활용함으로써, 공정흑연 폐기 과정에서 일어나는 환경오염 문제를 최소화할 수 있어 친환경적인 효과가 있다.In addition, according to the present invention by recycling the process graphite which is a by-product discarded after the diamond manufacturing process, it is possible to minimize the environmental pollution problem occurring during the process graphite disposal process has an environmentally friendly effect.
또한, 본 발명에 따르면 흑연에 잔존하는 황산용액을 최소화한 슬러리 상태로 흑연을 처리하여 황산(H2SO4) 및 과망간산칼륨(KMnO4)의 급격한 발열 반응을 최소화함으로써 폭발의 위험성을 최소화할 수 있다.In addition, according to the present invention by treating the graphite in a slurry state to minimize the sulfuric acid solution remaining in the graphite to minimize the risk of explosion by minimizing the rapid exothermic reaction of sulfuric acid (H 2 SO 4 ) and potassium permanganate (KMnO 4 ). have.
또한, 본 발명에 따르면 흑연에 잔존하는 황산용액을 최소화한 슬러리 상태로 흑연을 처리하여 황산(H2SO4) 및 과망간산칼륨(KMnO4)의 반응을 최소화함으로써, 해당 공정에서 온도의 상승을 제어하기 위한 별도의 제어 수단 또는 제어 방법이 불필요하게 됨으로써 폭발의 위험성 제거 이외에도 공정효율이 향상되는 효과를 얻을 수 있다.In addition, according to the present invention by controlling the graphite in a slurry state to minimize the sulfuric acid solution remaining in the graphite to minimize the reaction of sulfuric acid (H 2 SO 4 ) and potassium permanganate (KMnO 4 ), to control the rise in temperature in the process Since no separate control means or control method is necessary, it is possible to obtain an effect of improving process efficiency in addition to removing the risk of explosion.
도 1은 본 발명의 일 실시예에 따른 그래핀 제조방법을 나타내는 순서도이다.1 is a flow chart showing a graphene manufacturing method according to an embodiment of the present invention.
도 2는 다른 실시예에 따른 그래핀 제조방법을 나타내는 순서도이다.2 is a flow chart showing a graphene manufacturing method according to another embodiment.
본 발명에 따른 공정흑연을 이용한 그래핀 제조방법은 금속 및 흑연을 포함하는 혼합 분말을 소결하여 다이아몬드 및 미반응 흑연을 포함하는 소결체를 제조하는 제1단계; 상기 소결체를 강산 수용액에 침지하고 전기분해하여 다이아몬드 및 흑연을 포함하는 혼합물로 변환하는 제2단계; 상기 혼합물에 과망간산칼륨(KMnO4) 수용액을 투입하여 교반하는 제3단계; 상기 혼합물 내의 흑연을 박리시키는 제4단계; 상기 박리된 산화그래핀을 회수하는 제 5단계; 및 상기 회수된 산화 그래핀을 환원시키는 제 6단계;를 포함한다.Graphene manufacturing method using a process graphite according to the present invention comprises a first step of producing a sintered body comprising diamond and unreacted graphite by sintering a mixed powder containing a metal and graphite; A second step of immersing the sintered body in an aqueous strong acid solution and electrolyzing the mixture into a mixture containing diamond and graphite; A third step of stirring by adding an aqueous potassium permanganate (KMnO4) solution to the mixture; A fourth step of peeling the graphite in the mixture; A fifth step of recovering the exfoliated graphene oxide; And a sixth step of reducing the recovered graphene oxide.
이하 첨부된 도면을 참조하여 본 발명의 실시예를 설명한다. 특별한 정의나 언급이 없는 경우에 본 설명에 사용하는 방향을 표시하는 용어는 도면에 표시된 상태를 기준으로 한다. 또한 각 실시예를 통하여 동일한 도면부호는 동일한 부재를 가리킨다. 한편, 도면상에서 표시되는 각 구성은 설명의 편의를 위하여 그 두께나 치수가 과장될 수 있으며, 실제로 해당 치수나 구성간의 비율로 구성되어야 함을 의미하지는 않는다.Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Unless otherwise defined or mentioned, terms indicating directions used in the present description are based on the states shown in the drawings. In addition, the same reference numerals throughout the embodiments indicate the same member. On the other hand, each of the components shown in the drawings may be exaggerated in thickness or dimensions for the convenience of description, and does not mean that actually should be configured by the ratio between the dimensions or configurations.
먼저 도 1을 참조하여 본 발명의 일 실시예에 따른 그래핀 제조방법을 설명한다. 도 1은 본 발명의 일 실시예에 따른 그래핀 제조방법을 나타내는 순서도이다.First, a graphene manufacturing method according to an embodiment of the present invention will be described with reference to FIG. 1. 1 is a flow chart showing a graphene manufacturing method according to an embodiment of the present invention.
본 실시예에 따른 그래핀 제조방법은 금속분말 및 흑연분말을 소결하여 다이아몬드 및 미반응 흑연을 포함한 소결체를 제조하는 제1단계(S100), 소결체를 산(acid) 용액에 침지하고 전기분해하여 다이아몬드 및 흑연을 포함하는 혼합물로 변환하는 제2단계(S200), 상기 혼합물에 과망간산칼륨(KMnO4) 수용액을 투입하여 교반하는 제 3단계(S300), 혼합물 내의 공정흑연을 박리시키는 제 4단계(S400), 박리된 산화 그래핀을 회수하는 5단계(S500), 회수된 산화 그래핀을 환원시키는 제 6단계(S600)를 포함한다.Graphene manufacturing method according to the present embodiment is a first step (S100) of producing a sintered body including diamond and unreacted graphite by sintering metal powder and graphite powder, the sintered body is immersed in an acid solution and electrolyzed to diamond And a second step (S200) of converting to a mixture containing graphite, a third step (S300) of stirring by adding an aqueous solution of potassium permanganate (KMnO 4 ) to the mixture, and a fourth step (S400) of removing process graphite in the mixture. ), A fifth step (S500) of recovering the exfoliated graphene oxide, and a sixth step (S600) of reducing the recovered graphene oxide.
제1단계(S100)에서는 금속분말 및 흑연분말을 펠렛 형태로 제조한 후 고온고압 조건에서 소결하여 소결체를 형성한다. 이때 금속분말은 철, 니켈, 코발트 중 적어도 어느 하나를 촉매로서 포함할 수 있다. 흑연과 철, 니켈, 코발트 분말을 일정 크기의 셀에 넣고 고온고압으로 소결한다. 이 경우 소결은 500 ~ 3000℃의 온도, 40,000 ~ 60,000atm의 압력에서 40~80분 동안 수행될 수 있다.In the first step (S100) to prepare a metal powder and graphite powder in the form of pellets and then sintered under high temperature and high pressure conditions to form a sintered body. In this case, the metal powder may include at least one of iron, nickel, and cobalt as a catalyst. Graphite, iron, nickel, and cobalt powder are put in a cell of a certain size and sintered at high temperature and high pressure. In this case, the sintering may be performed for 40 to 80 minutes at a temperature of 500 ~ 3000 ℃, pressure 40,000 ~ 60,000 atm.
제2단계(S200)에서는 소결체를 산(acid)용액을 침지하고 전기분해한다. 상술한 소결체는 다이아몬드, 미반응 흑연 및 촉매 금속등이 혼재된 상태로 형성된다. 이 경우 해당 소결체는 물리적인 방법으로 다이아몬드, 흑연 및 촉매 금속 등으로 분리가 어렵다, 따라서 제2단계에서는 소결체를 각각 다이아몬드, 흑연 및 촉매 금속으로 분리하여 물리적으로 분리가 용이한 혼합물의 상태로 변환시킨다. 이 때 최초 흑연 투입량의 10%만 다이아몬드로 존재하며, 미반응된 나머지 공정흑연 90%과 금속분말이 혼합물 내에 존재한다. 특별히 공정흑연의 경우, 고온고압의 처리를 받아 흑연 층간 팽창이 일어났으며, 이는 산화 그래핀 박리 공정에 유리한 형태로 작용한다. In the second step (S200), the sintered body is immersed in an acid solution and electrolyzed. The sintered body described above is formed in a state in which diamond, unreacted graphite, a catalyst metal, and the like are mixed. In this case, the sintered body is difficult to be separated into diamond, graphite, and catalytic metal by physical methods. Therefore, in the second step, the sintered body is separated into diamond, graphite, and catalytic metal, respectively, and converted into a physically easy mixture. . At this time, only 10% of the initial graphite input is present as diamond, and the remaining 90% unreacted process graphite and metal powder are present in the mixture. Particularly, in the case of process graphite, graphite intercalation occurred under high temperature and high pressure treatment, which acts in an advantageous form for the graphene oxide exfoliation process.
한편, 이때 사용되는 산(acid)용액은 황산(H2SO4), 인산(H3PO4), 질산(HNO3) 및 염산(HCl) 중 어느 하나를 적용할 수 있다. 본 발명에서는 황산(H2SO4)을 사용하는 것이 바람직하나, 반드시 이에 한정되는 것은 아니다. Meanwhile, the acid solution used at this time may be any one of sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ) and hydrochloric acid (HCl). In the present invention, it is preferable to use sulfuric acid (H 2 SO 4 ), but is not necessarily limited thereto.
다음으로 제3단계(S300)에서는 산처리된 공정흑연 슬러리에 과망간산칼륨 (KMnO4) 수용액을 투입하거나 또는 과망간산칼륨(KMnO4) 수용액에 산처리된 공정흑연 슬러리를 투입하여 그래핀 층간에 산소 관능기를 형성/삽입시킨다. 이때 과망간산칼륨(KMnO4) 수용액의 농도를 조절하여 산화 흑연 슬러리에 투입함으로써 황산(H2SO4)과의 반응속도를 조절할 수 있다. 예를 들어 과망간산칼륨(KMnO4) 수용액을 형성하여 산화 흑연 슬러리에 투입하거나, 과망간산칼륨(KMnO4) 수용액에 산화 흑연 슬러리를 투입함으로써 폭발의 위험성을 줄이거나 배제한 상태에서 제3단계에 따른 공정을 진행할 수 있다.Next, the third step (S300) in the acid treatment of step a graphite slurry of potassium permanganate in (KMnO 4) input, or potassium permanganate (KMnO 4) and the aqueous solution added to the acid treatment of the process of graphite slurry in graphene oxygen functional group in the interlayer of an aqueous solution Form / Insert. At this time, by adjusting the concentration of the potassium permanganate (KMnO 4 ) aqueous solution to the graphite oxide slurry can be adjusted the reaction rate with sulfuric acid (H 2 SO 4 ). For example, potassium permanganate (KMnO 4) forming an aqueous solution were charged into a graphite oxide slurry, or by injecting the graphite oxide slurry in potassium permanganate (KMnO 4) aqueous solution of the process according to the third step in the exclusion or eliminate the danger of an explosion condition You can proceed.
한편, 제3단계에서 과망간산칼륨(KMnO4) 수용액에는 질산나트륨을 더 포함할 수 있다. 또한 5%의 황산(H2SO4)을 첨가제(반응활성화)로 첨가하는 과정을 더 포함할 수 있다. 이처럼 5% 황산(H2SO4)을 첨가제로 첨가하여 과망간산칼륨(KMnO4) 수용액을 투입하는 경우 그래핀 층간 산소관능기 삽입이 좀더 원활하고 안정적으로 이루어질 수 있으며 첨가제의 첨가량에 따라 부가적으로 반응의 속도제어도 가능하다. On the other hand, in the third step potassium permanganate (KMnO 4 ) aqueous solution may further include sodium nitrate. In addition, the method may further include adding 5% sulfuric acid (H 2 SO 4 ) as an additive (reaction activation). As such, when 5% sulfuric acid (H 2 SO 4 ) is added as an additive and potassium permanganate (KMnO 4 ) aqueous solution is added, graphene interlayer oxygen functional group insertion can be made more smoothly and stably. Speed control is also possible.
다음으로 제4단계(S400)에서는 산처리된 폐 공정흑연에 열처리 또는 초음파를 조사하여 그래핀을 박리시킨다. Next, in the fourth step (S400), the graphene is peeled off by irradiating heat treatment or ultrasonic waves to the acid-treated waste process graphite.
또한 제 5단계(S500)에서는 박리된 산화 그래핀을 원심분리, 여과 등의 방법을 통해서 회수한다. In addition, the fifth step (S500) to recover the exfoliated graphene oxide by centrifugation, filtration and the like.
산화그래핀 자체를 용도에 따라 그대로 사용할 수도 있지만, 그래핀 본래의 전기적, 물리적 특성을 활용하기 위해서는 산화그래핀을 물리화학적 방법을 통해 환원시켜야 한다. 일반적으로 산화 그래핀을 환원하기 위해 하이드라진계 환원제 및/또는 수소를 이용한 고온 열처리 과정 등을 거치게 된다.Although graphene oxide itself may be used as it is, it is necessary to reduce graphene oxide through a physicochemical method in order to utilize the original electrical and physical properties of graphene. In general, a high temperature heat treatment process using a hydrazine-based reducing agent and / or hydrogen to reduce the graphene oxide.
제6단계(S600)에서는 산화 그래핀을 환원시켜 사용 목적에 맞도록 전기적 특성 등을 향상시킨다. 다만, 본 발명에 따른 그래핀 제조방법은 공지된 환원 방법들을 다양하게 적용이 가능하며, 특별한 제한은 없다.In the sixth step (S600) to reduce the graphene oxide to improve the electrical properties, etc. to meet the purpose of use. However, the graphene manufacturing method according to the present invention can be applied to a variety of known reduction methods, there is no particular limitation.
화학적 환원법에 사용되는 시약은 하이드라진계가 주로 사용된다. 하이드라진이나 나트륨 하이드라이드를 환원제로 사용하는 경우 그래핀 표면의 에폭시기나 히드록시기는 효과적으로 제거하지만 가장자리에 위치한 카보닐기나 카르복실기는 제거하지 못하는 것으로 알려져 있다. 이러한 잔류 관능기는 황산처리나 고온 열처리를 통해 제거가 가능하다. 열적 환원은 불활성 가스나 환원 가스 환경에서 200도 이상의 온도에서 이루어진다. 산화 그래핀에서 산소의 탈착은 200도 이상의 높은 온도에서는 빠르게 일어나고 200도 이하의 온도에서는 점진적으로 일어난다.As the reagent used in the chemical reduction method, a hydrazine system is mainly used. When hydrazine or sodium hydride is used as a reducing agent, it is known to effectively remove epoxy groups or hydroxyl groups on the graphene surface but not carbonyl or carboxyl groups located at the edges. Such residual functional groups can be removed by sulfuric acid treatment or high temperature heat treatment. Thermal reduction occurs at temperatures above 200 degrees in an inert gas or reducing gas environment. Desorption of oxygen in graphene oxide occurs rapidly at high temperatures above 200 degrees and gradually occurs at temperatures below 200 degrees.
하이드라진계 환원제의 대체 재료로는 하이드로퀴논(hydroquinone), 나트륨 보로하이드라이드(sodium borohydride)가 연구되었다. 친환경 환원제로는 아스코빅산(ascorbic acid), 글루코스(glucose) 등의 환원제가 보고되고 있다. 그 밖에 염기성 수용액, 증류수나 디메틸포름아미드(DMF), 메틸아세트아미드, n-메틸피롤리디논(NMP) 등의 유기용매에서 일반 가열을 통해 탈산화 반응을 유도하거나 마이크로파(mircowave)를 이용해 5~15분 정도의 짧은 시간에 환원을 시키는 방법이 연구되고 있다. 이처럼 산화 그래핀의 환원은 염기용액이나 초임계 수용액, 심지어 용매 내에서도 이루어질 수 있어 산화 그래핀의 화학적 구조분석 시 유의하여야 한다. 또한 수소플라즈마 처리에 의해 효과적으로 환원시킬 수 있으며, 그 밖에 전기화학적 환원법, 광촉매 환원법, 플래쉬 컨버전(Flash conversion)법 등이 있다.Hydroquinone and sodium borohydride have been studied as alternative materials for hydrazine-based reducing agents. As an eco-friendly reducing agent, reducing agents such as ascorbic acid (glucose), glucose (glucose) has been reported. Other organic solvents such as basic aqueous solution, distilled water, dimethylformamide (DMF), methylacetamide, and n-methylpyrrolidinone (NMP) induce deoxidation reactions through normal heating or by using microwaves A method of reducing in a short time of about 15 minutes has been studied. As such, the reduction of graphene oxide may be performed in a basic solution, a supercritical aqueous solution, or even a solvent, and therefore, care should be taken when analyzing the chemical structure of graphene oxide. In addition, it can be effectively reduced by the hydrogen plasma treatment, there are other electrochemical reduction, photocatalyst reduction, flash conversion (Flash conversion) method and the like.
도 2를 참조하여 다른 실시예에 따른 공정흑연을 이용한 그래핀 제조방법을 설명한다. 도 2는 다른 실시예에 따른 공정흑연을 이용한 그래핀 제조방법을 나타내는 순서도이다.With reference to Figure 2 will be described a graphene manufacturing method using a process graphite according to another embodiment. 2 is a flowchart illustrating a graphene manufacturing method using eutectic graphite according to another embodiment.
종래의 그래핀 제조공정에서는 황산(H2SO4) 수용액에 흑연 분말을 투입하여 산화 흑연 분말을 수용액 상에서 분산시켜 산화흑연 박막플레이트를 형성한 후, 과망간산칼륨(KMnO4) 파우더를 서서히 투입하여 그래핀 층간에 산소 관능기를 삽입하였다. 하지만 이러한 방법은 과망간산칼륨(KMnO4) 파우더로 그래핀 층간에 산소 관능기를 삽입하는 과정에서 황산과의 급격한 발열반응으로 인한 폭발의 위험성이 잔존하여 투입량 및 투입 속도를 조절하여 급격한 온도 상승을 방지하는 방법으로 그래핀을 제조해야만 하는 단점이 있었다. 또한, 이러한 방법은 실험실 단위의 소규모 제조에서는 관리가 용이할 수 있으나, 공장단위에서 대량생산이 수행되는 경우에는 폭발의 위험성이 상존함으로써 작업자들의 안전이 위협받을 수 있으며 사고가 발생하는 경우에는 그 피해액이 막대하게 발생할 수 있어 보다 향상된 폭발 위험성의 관리방법이 필요하다.In a conventional graphene manufacturing process, graphite powder is added to an aqueous solution of sulfuric acid (H 2 SO 4 ) to disperse the graphite oxide powder in an aqueous solution to form a graphite oxide thin film plate, and then potassium permanganate (KMnO 4 ) powder is gradually added to the graphene. An oxygen functional group was inserted between the pin layers. However, this method uses potassium permanganate (KMnO 4 ) powder to prevent explosions due to rapid exothermic reaction with sulfuric acid in the process of inserting oxygen functional groups between graphene layers to prevent rapid temperature rise. There was a disadvantage in that the graphene must be prepared by the method. In addition, this method may be easy to manage in small-scale manufacturing at the laboratory level, but if the mass production is carried out at the factory level, the risk of explosion may exist and the safety of workers may be threatened. This can occur enormously and requires improved management of explosion risk.
혼합물 내의 흑연은 제2단계에서 황산(H2SO4)을 흡수한 슬러리 상태로 존재한다. 따라서 별도의 세척 또는 건조과정을 거쳐 흑연으로부터 산을 제거하는 과정을 거치지 않고, 부산물 내에 남아있는 잉여 황산을 여과 또는 일부 제거하는 단계만을 거쳐 사용할 수 있다. 혼합물 내에 존재하는 황산은 혼합물 내의 황산 전체 중량 대비 공정흑연에 흡수되지 않은 황산(H2SO4)의 비율이 5% 이내가 되도록 일부 또는 전부 제거함으로써 잔여 산용액을 최소화하는 단계(S600)를 더 포함할 수 있다. Graphite in the mixture is present in the slurry that has absorbed sulfuric acid (H 2 SO 4) in step 2. Therefore, it may be used only through the step of filtration or partial removal of surplus sulfuric acid remaining in the by-product, without undergoing a process of removing acid from the graphite through a separate washing or drying process. Sulfuric acid present in the mixture is further removed to minimize the residual acid solution (S600) by removing some or all of the sulfuric acid (H 2 SO 4 ) not absorbed in the process graphite to the total weight of sulfuric acid in the mixture to be within 5%. It may include.
이처럼 부산물 내의 잉여 황산의 비율이 5% 이내가 되도록 제어하는 단계를 포함하여, 잔존하는 황산(H2SO4) 용액을 최소화한 상태가 되면 제3단계(S300)에서 과망간산칼륨(KMnO4) 수용액이 투입되는 경우 온도의 제어가 용이하며 폭발의 위험성을 줄일 수 있다. 즉, 황산과 과망간산칼륨이 순간적으로 접촉하는 양을 최소화시킬 수 있으며, 과망간산칼륨(KMnO4) 수용액이 흑연의 판상 구조 사이로 침투하는 시간에 비례하여 황산(H2SO4)과 과망간산칼륨(KMnO4)의 반응 시간이 증가하기 때문에 급격한 온도 상승의 문제까지 해소될 수 있다. 또한 그래핀 제조 시, 원료로 사용되는 흑연을 다이아몬드 제조공정의 부산물로 배출되는 공정흑연으로 대체하여 재사용함으로써 원료비용을 절감할 수 있는 효과가 있다. As such, the method includes controlling the amount of surplus sulfuric acid in the byproduct to be within 5%, and when the remaining sulfuric acid (H 2 SO 4 ) solution is minimized, the solution of potassium permanganate (KMnO 4 ) in the third step (S300). If it is injected, the temperature can be easily controlled and the risk of explosion can be reduced. That is, the amount of sulfuric acid and potassium permanganate instantaneous contact can be minimized, and the proportion of sulfuric acid (H 2 SO 4 ) and potassium permanganate (KMnO 4 ) is proportional to the time when the aqueous solution of potassium permanganate (KMnO 4 ) penetrates between the plate-like structures of graphite. Since the reaction time of) increases, the problem of sudden temperature rise can be solved. In addition, in the manufacture of graphene, it is possible to reduce the raw material cost by replacing the graphite used as a raw material with the process graphite discharged as a by-product of the diamond manufacturing process.
한편, 앞서 설명한 바와 같이 제2단계(S200)에서는 소결체를 황산 수용액에 침지한 후 전기분해를 통하여 분리함으로써 물리적인 방법을 통하여 다이아몬드, 흑연 및 촉매금속 들을 서로 회수하거나 분리하기가 용이한 혼합물 상태로 변환시킨다.Meanwhile, as described above, in the second step (S200), the sintered compact is immersed in an aqueous sulfuric acid solution and separated by electrolysis, thereby allowing the diamond, graphite, and catalytic metals to be easily recovered or separated from each other through a physical method. Convert
이와 같이 제2단계(S200)를 통하여 변환된 혼합물로부터 다이아몬드 등을 회수하는 공정(S800)은 제2단계(S200) 이후 어느 단계에서나 수행이 가능하다. 즉, 제2단계(S200) 이후 어느 단계에서 다이아몬드를 회수하거나, 귀금속을 추가적으로 더 분리 회수하는 것도 가능하며, 혼합물로부터 공정흑연을 분리하여 정제(S900)하는 것도 가능하다. 즉, 산화흑연은 갈색의 점성 슬러리 형태로 제조되며 산화흑연, 박리된 박막산화 플레이트, 산화되지 않은 흑연 조각 및 산화제의 잔유물들로 형성되어 있다. 따라서 산화흑연은 원심분리를 통한 정제과정(S900)을 통하여 가라앉는 불순물들을 제거하고 산화흑연을 선택적으로 걸러 정제된 산화흑연을 수득함으로써 그래핀의 품질 및 수율을 향상시킬 수 있다. 혼합물로부터 공정흑연을 분리하는 과정은 중력 여과, 가압 여과, 감압 여과, 원심 여과, 삼투 여과 등 공지된 여과 방법들을 다양하게 적용가능하며, 여과 방법에 대한 특별한 제한은 없다.As such, the process of recovering diamond or the like from the mixture converted through the second step S200 may be performed at any step after the second step S200. That is, it may be possible to recover the diamond at any stage after the second step (S200), or to further collect and recover precious metals, or to separate and refine the process graphite from the mixture (S900). That is, the graphite oxide is prepared in the form of a brown viscous slurry, and is formed of graphite oxide, exfoliated thin film oxide plate, unoxidized graphite chips and residues of oxidizing agent. Therefore, the graphite oxide may improve the quality and yield of graphene by removing impurities that sink through the purification process (S900) through centrifugation and selectively filtering graphite oxide to obtain purified graphite oxide. The process of separating the process graphite from the mixture is applicable variously known filtration methods such as gravity filtration, pressure filtration, reduced pressure filtration, centrifugal filtration, osmotic filtration, there is no particular limitation on the filtration method.
이후, 일반적인 공정으로서 세척을 위하여 과산화수소(H2O2)처리(S700)를 할 수 있다.Thereafter, as a general process, hydrogen peroxide (H 2 O 2 ) treatment (S700) may be performed for washing.
이하에서는 본 발명에 따른 공정흑연을 이용한 그래핀 제조방법의 구체적인 바람직한 실시예 및 해당 실시예에 따른 각 단위 공정들을 상세히 설명한다.Hereinafter, a specific preferred embodiment of the graphene manufacturing method using the process graphite according to the present invention and each unit process according to the embodiment will be described in detail.
본 실시예에 따른 공정흑연을 이용한 그래핀 제조방법에 따라 흑연분말과 금속분말인 철, 니켈, 코발트 분말을 일정한 크기의 셀에 넣고, 1500℃의 온도와 50,000atm 기압 하에서 60분동안 소결한다. 소결한 결과물을 묽은 황산에 침지하여 전기분해한다. 전기분해 후 변환된 혼합물 내에서 다이아몬드와 미반응된 부산물을 중력 여과하여 분리해낸다. According to the graphene manufacturing method using the process graphite according to this embodiment, the graphite powder and the metal powder iron, nickel, cobalt powder is put in a cell of a constant size, and sintered for 60 minutes under a temperature of 1500 ℃ and 50,000 atm pressure. The sintered product is electrolyzed by dipping in dilute sulfuric acid. After electrolysis, diamond and unreacted byproducts are separated by gravity filtration in the converted mixture.
제2단계에서 금속분말 및 흑연 소결물을 침지하기 위한 산(acid) 용액은 황산을 사용하는 것이 바람직하나, 인산(H3PO4), 질산(HNO3) 및 염산 중 적어도 어느 하나를 이용하는 것도 가능하다. In the second step, an acid solution for immersing the metal powder and the graphite sintered material is preferably sulfuric acid, but at least one of phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ), and hydrochloric acid may be used. It is possible.
이후 부산물에 포함된 황산 전체 중량 대비 흑연 내에 흡수되지 않고 잔존하는 황산의 비율이 5% 이내가 되도록 제어하여 부산물이 슬러리 형태를 형성하도록 한다. 이때 흑연 내 흡수되지 않은 황산(H2SO4)의 비율이 5%를 초과하여 황산용액이 흑연 외부에 잔존하게 되는 경우에는, 과망간산칼륨(KMnO4) 수용액을 투입하여 교반하는 제4단계에서 온도의 갑작스런 상승으로 인한 폭발의 위험성이 증가할 수 있는 문제점이 있어 종래의 폭발 관리 제어 등의 공정 및 시스템이 다시 필요하게 된다. 하지만 본 발명에서와 같이 공정흑연 내 미흡수된 잔존 황산이 최소화된 상태가 되면 흑연의 층간 확장이 이미 충분히 일어나는 반면, 제3단계에서 과망간산칼륨(KMnO4) 수용액을 투입하더라도 폭발의 위험성을 최소화할 수 있다.Thereafter, by controlling the ratio of sulfuric acid remaining without being absorbed in the graphite to the total weight of sulfuric acid contained in the by-products within 5%, the by-products form a slurry form. At this time, when the ratio of sulfuric acid (H 2 SO 4 ) not absorbed in the graphite exceeds 5% and the sulfuric acid solution remains outside the graphite, the temperature in the fourth step of adding and stirring the aqueous potassium permanganate (KMnO 4 ) solution There is a problem that can increase the risk of explosion due to the sudden rise of the conventional process and system such as explosion management control is required again. However, when the unabsorbed residual sulfuric acid in the process graphite is minimized as in the present invention, the interlayer expansion of the graphite is already sufficiently performed, whereas the addition of an aqueous potassium permanganate (KMnO 4 ) solution in the third step may minimize the risk of explosion. Can be.
다음으로 제2 단계(S200)를 거친 흑연 슬러리에 과망간산칼륨(KMnO4) 수용액을 투입하여 교반한다. 과망간산칼륨(KMnO4)은 파우더 입자가 아닌 과망간산칼륨(KMnO4) 수용액을 사용하는 것이 바람직하며, 산처리된 슬러리 형태의 공정흑연에 투입하여 교반한다.Next, a potassium permanganate (KMnO 4 ) aqueous solution is added to the graphite slurry passed through the second step (S200), followed by stirring. Potassium permanganate (KMnO 4 ) is preferably used as an aqueous solution of potassium permanganate (KMnO 4 ) rather than powder particles, it is added to the process graphite in the form of acid-treated slurry and stirred.
과망간산칼륨(KMnO4)을 이용한 종래의 그래핀 제조과정은 흑연과 황산(H2SO4)의 혼합물에 과망간산칼륨(KMnO4), 특히 파우더 형태의 과망간산칼(KMnO4)륨을 투입할 때, 혼합물의 온도 상승으로 인한 폭발의 위험성 때문에 소량씩 온도를 조절해가며 투입해야만 하는 번거로움이 있어 대량생산에 적용할 수 없었다. 하지만 미흡수된 황산이 5% 이내의 범위를 갖도록 여과과정을 거처 잔존하는 황산(H2SO4)의 양을 최소한으로 감소시킴으로써 과망간산칼륨(KMnO4)의 투입 시 황산(H2SO4)과 과망간산칼륨(KMnO4) 수용액의 급격한 반응으로 인한 온도상승 및 폭발의 위험성을 현저히 줄일 수 있다. 이와 같이 본 실시예에 따른 다이아몬드 제조공정 부산흑연을 이용한 그래핀 제조방법은 그래핀의 대량생산에 적합하다.Conventional graphene manufacturing process using potassium permanganate (KMnO 4) is when the input of potassium permanganate (KMnO 4), in particular a powder form of permanganate knife (KMnO 4) of cerium to the mixture of graphite and sulfuric acid (H 2 SO 4), Due to the risk of explosion due to the rise of the temperature of the mixture, it was inconvenient to control the temperature in small amounts and thus could not be applied to mass production. However, sulfuric acid remaining living quarters the filtration is insufficient number of sulfuric acid to have a range of 5% sulfuric acid the time of preparation of potassium permanganate (KMnO 4) by reducing the amount of (H 2 SO 4) to a minimum (H 2 SO 4) and The risk of temperature rise and explosion due to the rapid reaction of aqueous potassium permanganate (KMnO 4 ) solution can be significantly reduced. As such, the graphene manufacturing method using the graphite manufacturing process Busan graphite according to the present embodiment is suitable for mass production of graphene.
한편, 산화흑연은 갈색의 점성 슬러리 형태로 제조되며 산화흑연, 박리된 박막산화 플레이트, 산화되지 않은 흑연 조각 및 산화제의 잔유물들로 형성되어 있다. 산화흑연은 원심분리를 통한 정제과정을 거칠 수 있으며, 이때 가라앉는 불순물들을 제거하고 부유물인 산화흑연을 선택적으로 걸러낼 수 있다.Graphite oxide, on the other hand, is prepared in the form of a brown viscous slurry and is formed of graphite oxide, exfoliated thin film oxide plates, unoxidized graphite pieces and residues of oxidants. The graphite oxide may be subjected to purification through centrifugation, at which time it is possible to remove the sinking impurities and selectively filter the suspended graphite oxide.
다음으로 공정흑연을 초음파 분쇄하여 산화흑연으로 분리한다. 정제된 산화흑연은 초음파분쇄를 통하여 염기성 수용액이나 유기용매에 분산되며, 이때 산화그래핀 형태로 박리되게 된다. 보다 균일한 단일층 및 면적을 갖는 산화그래핀은 초음파 분쇄 후 밀도구배형-원심분리과정을 통하여 얻어지게 된다.Next, the process graphite is ultrasonically pulverized and separated into graphite oxide. The purified graphite oxide is dispersed in a basic aqueous solution or an organic solvent through ultrasonic grinding, and at this time, it is exfoliated in the form of graphene oxide. Graphene oxide having a more uniform monolayer and area is obtained through a density gradient-centrifugation process after ultrasonic grinding.
또한 이와 같은 박리 단계는 고압식 호모게나이져(homogenizer)를 이용하여 전단응력을 인가시켜 산화그래핀을 분리해내는 것도 가능하다. In addition, such a peeling step is possible to separate the graphene oxide by applying a shear stress using a high pressure homogenizer (homogenizer).
이후, 박리가 완료된 산화 그래핀을 환원시킨다. 산화 그래핀을 특정 용도에 사용하는 것도 가능하나 산화 그래핀은 전기적, 열적 특성을 잃어버린 그래핀의 형태라고 볼 수 있다. 따라서 그래핀의 손실된 전기적, 열적 특성을 복구시키기 위해 산화 그래핀을 환원시켜 최종적으로 환원 그래핀의 형태를 갖게 한다. 앞서 설명한 바와 같이 산화흑연을 환원시키는 환원제로서 하이드리진(hydrazine) 등을 사용할 수 있다.Then, the graphene oxide is peeled off is reduced. It is also possible to use graphene oxide for specific applications, but graphene oxide is a form of graphene that has lost its electrical and thermal properties. Therefore, in order to recover the lost electrical and thermal properties of graphene, the graphene oxide is reduced to finally form a reduced graphene. As described above, hydrazine or the like may be used as a reducing agent for reducing graphite oxide.
이상 본 발명의 바람직한 실시예에 대하여 설명하였으나, 본 발명의 기술적 사상이 상술한 바람직한 실시예에 한정되는 것은 아니며, 특허청구범위에 구체화된 본 발명의 기술적 사상을 벗어나지 않는 범주에서 다양하게 구현될 수 있다.Although the preferred embodiment of the present invention has been described above, the technical idea of the present invention is not limited to the above-described preferred embodiment, and may be variously implemented in a range without departing from the technical idea of the present invention specified in the claims. have.

Claims (16)

  1. 금속 및 흑연을 포함하는 혼합 분말을 소결하여 다이아몬드 및 미반응 흑연을 포함하는 소결체를 제조하는 제1단계;A first step of sintering a mixed powder containing metal and graphite to produce a sintered body including diamond and unreacted graphite;
    상기 소결체를 강산 수용액에 침지하고 전기분해하여 다이아몬드 및 흑연을 포함하는 혼합물로 변환하는 제2단계;A second step of immersing the sintered body in an aqueous strong acid solution and electrolyzing the mixture into a mixture containing diamond and graphite;
    상기 혼합물에 과망간산칼륨(KMnO4) 수용액을 투입하여 교반하는 제3단계;A third step of stirring by adding an aqueous potassium permanganate (KMnO4) solution to the mixture;
    상기 혼합물 내의 흑연을 박리시키는 제4단계;A fourth step of peeling the graphite in the mixture;
    상기 박리된 산화 그래핀을 회수하는 제5단계; 및A fifth step of recovering the exfoliated graphene oxide; And
    상기 박리된 산화 그래핀을 환원시키는 제6단계;A sixth step of reducing the exfoliated graphene oxide;
    를 포함하는 공정흑연을 이용한 그래핀 제조방법.Graphene manufacturing method using a process graphite comprising a.
  2. 제1항에 있어서,The method of claim 1,
    상기 제2단계 이후 및 상기 제3단계 이전에, 상기 혼합물 내에 포함되는 전체 강산의 중량 대비 상기 흑연에 흡수되지 않고 잔존하는 강산의 중량 비율이 5% 이내가 되도록 상기 강산을 일부 제거하는 산제거 단계를 더 포함하는 공정흑연을 이용한 그래핀 제조방법.After the second step and before the third step, an acid removal step of partially removing the strong acid so that the weight ratio of the strong acid remaining without absorbing the graphite to the weight of the total strong acid included in the mixture is within 5%. Graphene manufacturing method using a process graphite further comprising.
  3. 제2항에 있어서,The method of claim 2,
    상기 혼합물 내의 흑연은 슬러리 형태인 공정흑연을 이용한 그래핀 제조방법.Graphite in the mixture is graphene manufacturing method using a process graphite in the form of a slurry.
  4. 제1항에 있어서,The method of claim 1,
    상기 제2단계 이후 상기 혼합물로부터 다이아몬드를 회수하는 회수단계를 더 포함하는 공정흑연을 이용한 그래핀 제조방법.Graphene manufacturing method using a process graphite further comprising a recovery step of recovering diamond from the mixture after the second step.
  5. 제4항에 있어서,The method of claim 4, wherein
    상기 회수단계에서는 귀금속을 더 회수하는 공정흑연을 이용한 그래핀 제조방법.Graphene manufacturing method using the process graphite to further recover the precious metal in the recovery step.
  6. 제4항에 있어서,The method of claim 4, wherein
    상기 회수 단계 이후 상기 혼합물 내의 흑연을 정제시키는 단계를 더 포함하는 공정흑연을 이용한 그래핀 제조방법.Graphene manufacturing method using the process graphite further comprising the step of purifying the graphite in the mixture after the recovery step.
  7. 제1항에 있어서,The method of claim 1,
    상기 제3단계에서 농도 5%의 황산(H2SO4)을 더 투입하는 단계를 더 포함하는 공정흑연을 이용한 그래핀 제조방법.Graphene manufacturing method using a process graphite further comprising the step of further adding a sulfuric acid (H 2 SO 4) of 5% concentration in the third step.
  8. 제7항에 있어서,The method of claim 7, wherein
    상기 황산(H2SO4)은 상기 과망간산칼륨(KMnO4) 수용액에 혼합된 상태로 투입되는 공정흑연을 이용한 그래핀 제조방법.The sulfuric acid (H 2 SO 4 ) is a graphene manufacturing method using the process graphite is added to the mixed state in the aqueous potassium permanganate (KMnO 4 ) solution.
  9. 제1항에 있어서,The method of claim 1,
    상기 제3단계에서 상기 과망간산칼륨수용액은 질산나트륨(NaNO3)을 더 포함하는 공정흑연을 이용한 그래핀 제조방법.The potassium permanganate solution in the third step is a graphene manufacturing method using a process graphite further comprises sodium nitrate (NaNO 3 ).
  10. 제1항에 있어서,The method of claim 1,
    상기 제2단계에서 투입되는 산(acid)은 황산(H2SO4), 인산(H3PO4), 질산(HNO3) 및 염산(HCl) 중 적어도 어느 하나를 포함하는 공정흑연을 이용한 그래핀 제조방법.The acid introduced in the second step is a graph using process graphite including at least one of sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), nitric acid (HNO 3 ), and hydrochloric acid (HCl). Pin manufacturing method.
  11. 제1항에 있어서,The method of claim 1,
    상기 금속분말은 철, 니켈 및 코발트 중 적어도 어느 하나를 포함하는 공정흑연을 이용한 그래핀 제조방법.The metal powder is a graphene manufacturing method using a process graphite containing at least one of iron, nickel and cobalt.
  12. 제1항에 있어서,The method of claim 1,
    상기 제1단계에서 상기 소결은 500 내지 3000의 온도에서 수행되는 공정흑연을 이용한 그래핀 제조방법.In the first step, the sintering is a graphene manufacturing method using a process graphite is carried out at a temperature of 500 to 3000.
  13. 제1항에 있어서,The method of claim 1,
    상기 제1단계에서 상기 소결은 40000atm 내지 60000atm의 압력에서 수행되는 공정흑연을 이용한 그래핀 제조방법.In the first step, the sintering is a graphene manufacturing method using a process graphite is carried out at a pressure of 40000atm to 60000atm.
  14. 제1항에 있어서,The method of claim 1,
    상기 제1단계에서 상기 소결은 40 내지 80분 동안 수행되는 공정흑연을 이용한 그래핀 제조방법.In the first step, the sintering is a graphene manufacturing method using a process graphite is performed for 40 to 80 minutes.
  15. 제1항에 있어서,The method of claim 1,
    상기 제4단계는 열처리 또는 초음파의 조사를 통하여 수행되는 공정흑연을 이용한 그래핀 제조방법.The fourth step is a graphene manufacturing method using a process graphite is carried out by heat treatment or ultrasonic irradiation.
  16. 제1항에 있어서,The method of claim 1,
    상기 제6단계는 하이드리진(hydrazine), 나트륨 하이드라이드, 하이드로퀴논(hydroquinone), 나트륨 보로하이드라이드(sodium borohydride), 아스코빅산(ascorbic acid) 및 글루코스(glucose) 중 적어도 어느 하나의 환원제의 투입에 의하여 수행되는 공정흑연을 이용한 그래핀 제조방법.The sixth step is for the addition of at least one reducing agent of hydrazine, sodium hydride, hydroquinone, sodium borohydride, ascorbic acid and glucose. Graphene manufacturing method using a process graphite performed by.
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