| The crystal growth and dissolution of alkaline-earth fluorides are of a great importance in view of their involvement in spectroscopy, lasers electronics, glass manufacture and in the fluoridation of drinking waters. In the case of strontium fluoride, crystallization as strontium-90 fluoride, into large easily filtered crystals, offers an attractive method for removing this element from highly radioactive fission products. The proposed research is aimed at studying the kinetics of crystallization and dissolution of strontium fluoride using the highly reproducible constant solution composition technique in which the degree of saturation and ionic strength are kept constant. The experiments will be made in a nitrogen atmosphere over a wide range of super- and undersaturations. The solution composition will be maintained constant either by the addition of lattice ions for growth experiments, or of medium electrolyte for the dissolution reactions, using a fluoride ion-selective electrode coupled with a thermal-electrolytic silver/silver chloride reference electrode. The second part of this study will be concerned with adsorption of magnesium, calcium, zinc, aluminum, copper, lead and other ions on strontium fluoride crystals and their influence on the rates of both the growth and dissolution reactions. Concentrations of adsorbed species will be measured directly using ESCA methods. Changes in particles size, morphology and zeta potential will also be monitored. |
