A descriptive model for the homogeneous precipitation of zinc sulfide from acidic zinc salt solutions

Homogeneous precipitation of zinc sulfide (ZnS) is investigated by observing the induction time, particle size and particle morphology as a function of four parameters, e.g. pH, anion type. continuous phase viscosity and stirring rate. Based on these observations a descriptive model of the precipitation mechanism is presented. According to this model the homogeneous precipitation of ZnS proceeds in four stages. Initially nuclei are formed homogeneously throughout the solution. They are not stable and by a variety of coagulation processes the final particles are formed. Particle size and particle morphology are strongly influenced by the transition times between the four stages. (C) 1999 Elsevier Science B.V. All rights reserved.