Kinetics of crystallization and dissolution of lead sulphate in aqueous solution

Abstract

The crystallization and dissolution of lead sulphate have been studied by following the change in conductivity which occurs when supersaturated or subsaturated solutions are inoculated with seed crystals. The growth of the crystals follows a rate law, second-order with respect to supersaturation, and this region is preceded by an initial growth surge of effective order greater than two. The initial fast period is interpreted in terms of nucleation on the surface of the added crystals. This conclusion is supported by the results of crystal growth experiments made in the presence of various substances which are adsorbed at the crystal surfaces. The process of dissolution of lead sulphate follows a rate law second-order in subsaturation after an initial surge of short duration.