The kinetics of the chlorination of pyrite in two Turkish lignites in
water and water-carbon tetrachloride media at ambient pressure (congru
ent to 610 mm Hg) are investigated. The effects of speed of stirring (
5-20 s(-1)), particle size (74-88, 150-180 and 250-425 mu m), temperat
ure (13-70 degrees C) and reaction time (0-18 000 s) were studied, The
experimental data were analyzed on the basis of the unreacted shrinki
ng core model, The fine pyrite particles are assumed to be embedded in
side the coal particles, The rate-controlling step was found to be dif
fusion of chlorine through the ash (the coal matrix), The activation e
nergies were calculated as 25.1 kJ mol(-1) for Dadagi coal in water me
dium and 25.0 kJ mol(-1) for Mengen coal in water-carbon tetrachloride
medium. (C) 1997 Elsevier Science B.V.