Studies of the particle porosity as a function of residence time associated with the crystallization of high surface area burkeite (Na2CO3(Na2SO4)(2)) agglomerates revealed no evidence for Ostwald ripening. However, a significant increase in particle porosity was observed following milling, reflecting particle breakdown and the consequent exposure of more particle surface to the liquid phase. The action of spray drying was found to reverse this trend with the particulates so formed exhibiting a much lower porosity, reflecting the blocking of surface pores by recrystallized material.