A GENERAL SHRINKING-PARTICLE MODEL FOR THE CHEMICAL DISSOLUTION OF ALL TYPES OF CYLINDERS AND DISKS

There is a manifest lack of models with exact solutions for describing the kinetic behaviour of cylindrical solids in reactions under chemic al control and for determining the kinetic constants of the reaction s ystem. This paper deduces two models that offer exact solutions: one f or any type of cylinder with a diameter less than the height and anoth er for any type of disc with a diameter greater than the height. It is demonstrated that the approximate kinetic model proposed in the liter ature for cylinders is actually the exact model for a regular toroid. Finally, we propose a single model for any type of cylinder or disc, m aking use of the so-called kinetic sphere radius.