CRYSTALLIZATION AND DEPOSIT FORMATION OF LEAD SULFIDE FROM AQUEOUS-SOLUTIONS .2. MORPHOLOGY OF THE DEPOSITS

Results are reported on the morphology and the growth behavior of PbS deposits, formed in once-through pipe flow experiments. This method, through reproducible data, allows one to study the effects of pH, concentration, substrate material, temperature, and liquid salinity on the morphology of growing deposits. In general, low pH values favor the formation of relatively large PbS crystals, while a pH above the threshold (for induction of spontaneous nucleation) promotes the aggregation of crystallites formed in the bulk. Salinity is shown to play a significant role by drastically changing the shape of the deposited PbS crystals. Deposit morphology seems to be independent of substrate material and flow rate, while temperature promotes the formation of smaller and aggregated particles. © 1991.