A general shrinking-particle model for the chemical dissolution of crystalline forms

When actual solid systems are observed, be they organic, inorganic or mineral solids, all appear to have non-isometric crystalline and defined shapes. In this paper a general procedure for modelling the dissolution of any shape of crystalline solid in a chemical control regime is presented. The general equations are deduced for a triclinic prism, a body of the least symmetry, and are applicable to all bodies of the seven fundamental crystalline systems as particular cases. For simplicity, a radius of a kinetic sphere is defined and the relations between the radius and the fraction reacted are given to make it possible to follow chemically the reaction for all bodies of the seven crystalline systems. The influence of external shape (angles between faces and edges) and area of the surface/volume ratio in the kinetic behaviour are discussed.