A bituminous coal carbonized at high temperature was activated with carbon dioxide or water vapor to form active carbon. The raw carbon consists of random mixtures of two kinds of distinct small domains mutually complicated: one is amorphous carbon being oxidized easily and the other oxidation-proof graphite crystallite. During the activation, the amorphous carbon is predominantly oxidized and micropores are formed at its sites. The density of the amorphous region was 2.05 g cm(-3), and the fraction of the domain in the raw carbon was 45 wt%. A kinetic equation was derived for the oxidation at the amorphous region assuming the adsorption of activator molecules onto the surface.
