CHLORINATION KINETICS OF PYRITE MINERAL IN 2 TURKISH LIGNITES

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.