Proximate analyses were conducted on different size fractions of pure
vitrinite from two bituminous coals and demineralized vitrinite from o
ne of the coals. CO2 surface areas were also determined, to aid in ass
essing the possible influence of pore diffusion of volatiles in partic
les of different sizes. The results implied that for comminuted coals,
the particle size dependence of the measured volatile matter, after c
orrection for effects of mineral matter, is due almost entirely to dif
ferences in maceral composition. (C) 1997 Elsevier Science Ltd.