Modified thermally expanded graphite and method for producing same
The modified thermally expanded graphite addresses the balance between porosity and mechanical strength in existing methods by using a controlled thermal expansion process and specific mixture composition, resulting in a material suitable for diverse applications.
Patent Information
- Application Number
- PCT/RU2024/050241
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-09-30
- Filing Date
- 2024-10-01
- Publication Date
- 2025-07-03
AI Technical Summary
Existing methods for producing thermally expanded graphite do not achieve the desired balance between high porosity and mechanical strength, leading to materials that are either too brittle or too dense, limiting their practical applications.
A method involving the use of a specific initial mixture composition and controlled thermal expansion process to produce modified thermally expanded graphite with enhanced porosity and mechanical strength, utilizing a mixture of graphite, metal particles, and a binder to achieve a balance between these properties.
The modified thermally expanded graphite exhibits improved porosity and mechanical strength, enabling broader applications in fields requiring both properties.
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Abstract
Description
[0001] Table!. Compositions of initial mixtures and yields of foamed graphite from examples 1-10
[0002]
[0003] Table 2. Properties of expanded graphites obtained in examples 1-10.
[0004] Note: the size of the metal particles on the surface of the PG in all examples is predominantly in the range from 0.01 to 1 µm (with the exception of particle aggregates, the sizes of which are somewhat larger).
[0005] 19
Claims
CLAUSE OF INVENTION 1. A dispersed bulk mixture for obtaining modified thermally expanded graphite, containing as components oxidized graphite, at least one metal nitrate hydrate with a melting point not exceeding 60°C, selected from the group comprising iron nitrate hydrate, cobalt nitrate hydrate, nickel nitrate hydrate and copper nitrate hydrate and at least one reducing agent selected from the group comprising urea and melamine, wherein the mixture contains components in the following ratios: Shgnm = (0.01 8.77) ■ Shgnm = (0.017 - 0.036) • shgnm + (0.28 - 0.67) • shgnm, where shgnm is the mass of metal nitrate hydrate, shgm is the mass of oxidized graphite, gpvost is the amount of reducing agent.
2. A mixture according to item 1, characterized in that copper nitrate hexahydrate is used as the copper nitrate hydrate.
3. A mixture according to item 1, characterized by the fact that oxidized graphite obtained using nitrate technology is used.
4. Modified thermally expanded graphite obtained from the mixture according to item 1 by thermal treatment of the mixture in an inert atmosphere.
5. A method for producing thermally expanded graphite according to item 4, modified with finely dispersed particles of metals and / or alloys, comprising preparing a mixture according to item 1, containing as components oxidized graphite obtained by nitrate technology, at least one metal nitrate hydrate with a melting point not exceeding 60°C, selected from the group comprising iron nitrate hydrate, cobalt nitrate hydrate, nickel nitrate hydrate and copper nitrate hydrate, and at least one reducing agent selected from the group comprising urea and melamine, dispersing the resulting mixture by heating to the melting points of the said metal nitrate hydrate in its own crystallization water, but not higher than 60°C, and then holding at this temperature for a time ensuring a decrease in the amount of crystallization water until the resulting dispersed mixture becomes free-flowing, then carrying out heat treatment in an inert atmosphere at 500-1080°C, wherein the said mixture contains components in the following ratios: Shgnm = (0.01 8.77) • Shog shvost = (0.017 - ь 0.036) • shog + (0.28 - ь 0.67) • shgnm, where shgnm is the mass of metal nitrate hydrate, shog is the mass of oxidized graphite, shvost is the amount of reducing agent required for the complete reduction of gases formed during the decomposition of OG and GNM to pure metal.
6. The method according to item 1, in which the heat treatment of the mixture containing iron nitrate hydrate is carried out at temperatures above 750°C.
7. The method according to item 1, in which the heat treatment is carried out at 900-1000°C.
8. The method according to item 1, in which a nitrogen or argon atmosphere is used as a neutral atmosphere.
9. The method according to item 1, in which copper nitrate hexahydrate is used as copper nitrate hydrate.
10. The method according to item 1, in which the dispersion of the mixture is carried out by grinding.
Citation Information
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