| Abstract: | An expression for determining the reaction zone thickness in a slab type solid pellet is derived based on the grain model for first order and isothermal reaction. It is shown that during reaction, the zone thickness remains constant for slab type pellets and varies for cylindrical and spherical shaped pellets. An approximate criterion is obtained from the expression for the applicability of the widely used shrinking core and homogeneous models. The expression is also useful for determining the rate parameters. The expression is found to be very satisfactory in predicting the experimental reaction zone thickness values and the activation energy value for the zinc sulphide oxidation reaction. |
