Enhanced dissolution of minerals: stored energy, amorphism and mechanical activation

A theoretical evaluation of the origin and role of stored energy in the phenomenon of mechanically-activated dissolution of finely milled minerals has been undertaken. The changing mechanical behaviour of minerals with decreasing particle size is examined, leading to the treatment of stored energy in terms of the generation and retention of crystalline imperfections (dislocations) during extended milling. Development of amorphism, and polymorphism, is treated as a direct consequence of decreased periodicity in the crystal lattice that is associated with an increased accumulation of dislocations. Quantitative estimates of stored energy are presented and used to quantify changes in dissolution kinetics in terms of a decreased activation energy of dissolution and hence, an increase in the relative rate of dissolution.