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WO2018183521A1 - Procédé et appareil à base de liquide pour la purification de graphite - Google Patents

Procédé et appareil à base de liquide pour la purification de graphite Download PDF

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Publication number
WO2018183521A1
WO2018183521A1 PCT/US2018/024873 US2018024873W WO2018183521A1 WO 2018183521 A1 WO2018183521 A1 WO 2018183521A1 US 2018024873 W US2018024873 W US 2018024873W WO 2018183521 A1 WO2018183521 A1 WO 2018183521A1
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WO
WIPO (PCT)
Prior art keywords
graphite
mixture
working
water
graphite flakes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2018/024873
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English (en)
Inventor
Boris Goldstein
Sergey Alekseev
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nano Graphene Inc
Original Assignee
Nano Graphene Inc
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Filing date
Publication date
Application filed by Nano Graphene Inc filed Critical Nano Graphene Inc
Publication of WO2018183521A1 publication Critical patent/WO2018183521A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/21—After-treatment
    • C01B32/215—Purification; Recovery or purification of graphite formed in iron making, e.g. kish graphite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B7/00—Combinations of wet processes or apparatus with other processes or apparatus, e.g. for dressing ores or garbage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B5/00—Other centrifuges
    • B04B5/10—Centrifuges combined with other apparatus, e.g. electrostatic separators; Sets or systems of several centrifuges

Definitions

  • Graphite as the most common polymorph of naturally occurring crystalline carbon, is required in production of many different goods, such as batteries, refractories, electrical products, and so on.
  • Graphite is a unique material since, as a covalent substance, it should not conduct electricity, yet it does.
  • Graphite is a carbon substance where three of its valence electrons are covalently bonded to three other carbon atoms. However, the fourth valence electron is left unbounded, and, therefore, can move freely. Such valence electrons allow electric currents to flow through graphite.
  • Gangue material and other impurities present in graphite are natural insulators and do not conduct electricity as well as graphite does.
  • concentration of carbon increases and concertation of gangue material decreases, the electric conductivity of a graphite crystal increases as well due to graphite's superior conductivity over gangue material.
  • the method and apparatus described in this invention comprise: a) preparing a working mixture of water and natural graphite flakes; b) placing the working mixture into a flow reactor; c) circulating the working mixture in the flow reactor thus, causing centrifugal flows of the solution and subsequent collisions of the graphite flakes it contains; d) purifying graphite flakes through leaching and washing off gangue materials; and e) separating resulting high purity graphite flakes from the working mixture.
  • the method and apparatus described herein provides for a significant increase of carbon content in graphite treated by this invention.
  • the effectiveness of the present invention has been confirmed by multiple tests observing spectral and elemental (purity) analysis.
  • 30-40% increase of electrical conductivity in graphite purified by the disclosed method has been observed.
  • the disclosed invention purifies graphite in cost-effective and ecologically-friendly way. Furthermore, this invention does not require substantial sources of energy nor sophisticated equipment, it can be implemented in a field near graphite depositories, which, in turn, would reduce transportation costs and overall costs of production.
  • FIG. l is the apparatus for removing gangue materials and other impurities from graphite flakes through centrifugal acceleration.
  • FIG.2A and FIG.2B depict SEM (Scanning Electron Microscope) images of purified graphite.
  • FIG.3 shows Raman spectra of purified graphite.
  • FIG.4 demonstrates XRD (X-ray diffraction) pattern of purified graphite.
  • FIG.5 shows FTIR spectra of purified graphite.
  • the gist of the proposed method and apparatus is application of centrifugal forces to the mixture of water and graphite flakes placed into a flow reactor equipped with a plurality of rotating impellers. As said impellers rotate, they are causing the mixture to move with high linear velocity, which, in turn, is causing graphite flakes to collide with each other and leach gangue material off the collided flakes.
  • high levels of centrifugal acceleration cause graphite flakes to swirl in the reactor resulting in higher levels of graphite-water friction, which, in turn, enhances effectiveness of removal of gangue material from graphite flakes.
  • the plurality of impellers 1 and 4 are rotated through a mechanical controller; thus, causing centrifugal acceleration and a plurality of streams of the working mixture, which streams collide at or about point of collision 2.
  • the diameter of impellers 1 and 4 are substantially similar to the inner width of reactor 3, providing a gap of no more than 0.8 mm.
  • the working mixture of water and graphite is prepared by mixing 15 kg of natural graphite with carbon content of 98% in 100 L of water. Said working mixture is then passed through the flow reactor at speeds of about 20 m/sec and temperatures in the range of 40-50 degrees Celsius. The foregoing process continues for about 15 minutes, after which the working mixture is separated into two fractions - small and large - using a generic centrifuge. Once the entire mixture is processed, the resulting aqueous paste is dehydrated and graphite flakes with high carbon content - up to 99.8 %, - are separated from the paste. Electric conductivity of the resulting graphite is increased by 30 - 35% comparing to the original graphite.
  • the present invention provides for ecologically clean and inexpensive method of purification of graphite with carbon content of up to 99.8% and high electrical and thermal conductivity.
  • the method and apparatus described herein use only one component - water - that can be re-used multiple times and without recycling.
  • the present invention does not require substantial sources of energy nor sophisticated equipment, it can be implemented in a field near graphite depositories, which, in turn, reduces the cost of transportation and overall cost of production.
  • FIG.2A and FIG.2B depicting SEM (Scanning Electron Microscope) images of purified graphite flakes. Different layers of graphite can be noticed. Each graphite flake comprises a plurality of near two-dimensional graphite layers called "graphene". Also noticeable is the absence of impurities on the graphite surface, which is indicative of graphite being free of impurities.
  • Image FIG.2B shows of a single purified graphite flake. A plurality of graphene layers free of impurities is noticeable. A plurality of small and thin graphite flakes can be seen around a large graphite flake.
  • FIG.3 showing Raman spectra of purified graphite.
  • Raman spectra was collected by measuring bulk material of purified graphite. Raman analysis is used to identify graphite structure, level of crystallinity and extent of defects present in flakes.
  • G peak is universal for all types of carbon based materials. The most characteristic peaks for graphite-like materials are D and 2D.
  • D peak represents an extent of defects present in the graphitic structure. The lower the D peak's intensity the purer the material. It can be seen that D peak's intensity is lower comparing to other peaks, which means graphite has fewer defects.
  • 2D peak's intensity is significantly higher and prominent, which means that graphite has crystalline and ordered structure. A 2D shoulder can be seen in the spectra, which corresponds to a standard multilayered graphitic structure.
  • FIG.4 showing XRD (X-ray diffraction) pattern of purified graphite, which is comparable to the standard graphitic structure.
  • Two main types of the graphitic structure are present in the spectra: (a) hexagonal (alpha) phase corresponding to the high intensity peak in the 2 ⁇ range 25-30; and (b) rhombohedral (beta) phase corresponding to the peak in the 2 ⁇ range 54-58. It is worth mentioning that the hexagonal structure is the most predominant.
  • FTIR spectra of purified graphite is shown. FTIR analysis was performed in order to identify gangue materials and other impurities chemically or physically attached to the graphitic structure. It can be seen from the spectra that impurities are attached to the graphite surface, either physically or chemically. A prominent CO2 absorption peak can be seen, which is most likely of the atmospheric nature.

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  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

La présente invention concerne un appareil et un procédé de purification de graphite par augmentation de la concentration de carbone dans des flocons de graphite par élimination de matériaux de gangue et d'autres impuretés par application d'une accélération centrifuge à un mélange d'eau et de flocons de graphite.
PCT/US2018/024873 2017-03-28 2018-03-28 Procédé et appareil à base de liquide pour la purification de graphite Ceased WO2018183521A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201762477742P 2017-03-28 2017-03-28
US62/477,742 2017-03-28

Publications (1)

Publication Number Publication Date
WO2018183521A1 true WO2018183521A1 (fr) 2018-10-04

Family

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Application Number Title Priority Date Filing Date
PCT/US2018/024873 Ceased WO2018183521A1 (fr) 2017-03-28 2018-03-28 Procédé et appareil à base de liquide pour la purification de graphite

Country Status (2)

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CN (1) CN108654828A (fr)
WO (1) WO2018183521A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2615349A (en) * 2022-02-07 2023-08-09 Graphene Star Ltd Improvements in or relating to graphite processing

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2787528A (en) * 1953-09-18 1957-04-02 Southwestern Graphite Company Process for purifying graphite
US5518189A (en) * 1993-08-03 1996-05-21 Harbison-Walker Refractories Company Beneficiation of flake graphite
US5560892A (en) * 1994-09-26 1996-10-01 Indresco Inc. Apparatus system for beneficiation of kish graphite
US20060043223A1 (en) * 2004-08-31 2006-03-02 Marcos Filgueiras Attrition scrubber apparatus and method
US20060062716A1 (en) * 2002-03-01 2006-03-23 Hydro-Quebec Method for the surface purification of a graphite containing impurities using a dilute aqueous solution of nh4f and h2so4
CN101367517A (zh) * 2008-09-24 2009-02-18 青岛恒胜石墨有限公司 蒸汽加热制备高纯石墨方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1258478C (zh) * 2004-01-21 2006-06-07 岳敏 天然鳞片石墨的纯化方法
US8420042B2 (en) * 2010-09-21 2013-04-16 High Temperature Physics, Llc Process for the production of carbon graphenes and other nanomaterials
CN103213972B (zh) * 2013-03-22 2015-01-14 中国科学院山西煤炭化学研究所 一种快速连续分离纯化氧化石墨的方法
CN205495102U (zh) * 2016-04-13 2016-08-24 深圳粤网节能技术服务有限公司 纯化装置和石墨烯生产系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2787528A (en) * 1953-09-18 1957-04-02 Southwestern Graphite Company Process for purifying graphite
US5518189A (en) * 1993-08-03 1996-05-21 Harbison-Walker Refractories Company Beneficiation of flake graphite
US5560892A (en) * 1994-09-26 1996-10-01 Indresco Inc. Apparatus system for beneficiation of kish graphite
US20060062716A1 (en) * 2002-03-01 2006-03-23 Hydro-Quebec Method for the surface purification of a graphite containing impurities using a dilute aqueous solution of nh4f and h2so4
US20060043223A1 (en) * 2004-08-31 2006-03-02 Marcos Filgueiras Attrition scrubber apparatus and method
CN101367517A (zh) * 2008-09-24 2009-02-18 青岛恒胜石墨有限公司 蒸汽加热制备高纯石墨方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2615349A (en) * 2022-02-07 2023-08-09 Graphene Star Ltd Improvements in or relating to graphite processing
WO2023148390A1 (fr) * 2022-02-07 2023-08-10 Graphene Star Limited Améliorations apportées ou se rapportant au traitement du graphite
GB2615349B (en) * 2022-02-07 2024-02-07 Graphene Star Ltd Improvements in or relating to graphite processing

Also Published As

Publication number Publication date
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