Method for producing expanded graphite

Abstract

Disclosed is a novel method for producing an expanded graphite which can be utilized for oil adsorbents, gaskets, packing sheets, adsorbents of volatile organic compounds and the like. SO3-graphite interlayer compound is formed by contacting graphite particles with SO3 generated from fuming sulfuric acid or anhydrous sulfuric acid. Excessive SO3 condensed on SO3-graphite interlayer compound is separated. Then, energy is applied to SO3-graphite interlayer compound to expand the graphite. An acid containing a single component can be continuously reused thus reducing the amount of the acid to {fraction (1/10)}-{fraction (1/100)} of that of an acid mixture used in the conventional method. As a result, the generation of a large amount of environmentally hazardous acid waste can be markedly reduced. Further, the concentration of sulfur remained in the expanded graphite also can be reduced, largely eliminating the corrosive effect of the expanded graphite onto metals when used for gaskets, packing sheets and the like.

Dependencies are inferred from the claim text.