US4091083A
Expired / Lapsed
US
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Method for the production of graphite-hydrogensulfate
Assignee: SIGRI ELEKTROGRAPHIT GmbH
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Filing: 1977-02-11
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Granted: 1978-05-23
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Expires: 1997-02-11
Abstract
Abstract Production of graphite-hydrogensulfate by dispersing crystalline graphite particles in sulfuric acid, agitating the mixture, adding hydrogen peroxide to the agitated dispersion and continuing agitation until the graphite is converted to graphite-hydrogensulfate. Excess acid is separated and the residual acid in the solid product is removed by washing. The graphite-hydrogensulfate may be heated to transform it into expanded graphite. The method minimizes pollution of the atmosphere with noxious gases and also makes possible ready recovery of unused acid.
Inventors
- 👤 Alfred Hirschvogel
- 👤 Friedrich Wagner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:51
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/52; C04B35/536; C01; C01B; C01B32/00; C01B32/20; C01B32/21; C01B32/23
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
Method for the manufacture of graphite-hydrogensulfate which comprises dispersing ground particles of crystalline graphite having at most a small amount of fine particles of less than 0.075 mm, in sulfuric acid, agitating the mixture of graphite particles and sulfuric acid to maintain the particles in a dispersed state in the sulfuric acid, admixing 2-5 parts by weight hydrogen peroxide to 100 parts by weight sulfuric acid by thereafter adding a 80-90% hydrogen peroxide to the agitated dispersion and continuing the agitation until the graphite is converted to graphite-hydrogensulfate, separating the liquid containing acid from the solid converted graphite in the dispersion, and washing the solid to remove residual acid in the solid.
Claim 2
Dependent Claim
112 words
Method for the manufacture of graphite-hydrogensulfate which comprises dispersing ground particles of crystalline graphite having at most a small amount of fine particles of less than 0.075 mm, in sulfuric acid, agitating the mixture of graphite particles and sulfuric acid to maintain the particles in a dispersed state in the sulfuric acid, admixing 2-5 parts by weight hydrogen peroxide to 100 parts by weight sulfuric acid by thereafter adding a 80-90% hydrogen peroxide to the agitated dispersion and continuing the agitation until the graphite is converted to graphite-hydrogensulfate, separating the liquid containing acid from the solid converted graphite in the dispersion, and washing the solid to remove residual acid in the solid.
Claim 3
Dependent Claim
26 words
Method according to claim 1 wherein 150-200 parts by weight of the hydrogen peroxide and sulfuric acid are reacted with 100 parts by weight of graphite.
Claim 4
Dependent Claim
28 words
Method according to claim 1 wherein said acid separated from the solid converted graphite is concentrated by the addition of oleum and recycled for further reaction with graphite.
Claim 5
Dependent Claim
17 words
Method according to claim 1 wherein the graphite-hydrogensulfate is heated to cause swelling and produces expanded graphite.
Claim 6
Dependent Claim
17 words
Method according to claim 2 wherein the graphite-hydrogensulfate is heated to cause swelling and produces expanded graphite.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |