Abstract:

Five sets of vitrain samples were extracted in stepwith organic solvents such as carbon disulfide， benzene， acetone
and tetrahydrofuran. The isothermal methane adsorptivity of the raw and extracted samples was measured， and the dynamics of
the adsorption differences among extracted samples were analyzed. It was found that the step extraction changes the adsorptivity
but the change direction and magnitude depends on the coalification degree， in which the second coalification jump plays a key
role on the adsorption change. It was suggested that the change may be originated in two major mechanisms， i.e.， the physical
expansion and chemical shrinkage of adsorption space. Carbon disulfide extraction produces a physical expansion effect to
flame， gas and early coking coals but a chemical shrinkage effect to late coking coal and anthracite. Damage of the benzene and
tetrahydrofuran extractions to the adsorptivity is mainly resulted from chemical shrinkage and the effect of acetone extraction is
mainly expressed as the physical expansion.