Mineral Precipitation Sequence During Evaporation of Lake Katwe Brine

Abstract

Traditional salt mining techniques are the dominant salt extraction methods at Lake Katwe in Uganda. In this work, the effect of temperature on the mineral precipitation sequence during evaporation of lake brine was studied to foster the design of a commercial salt extraction process. Isothermal evaporation experiments at different temperatures were undertaken. PHREEQC was used to predict the precipitation sequence. The precipitates were characterised by the XRD and SEM techniques. Halite is the most abundant mineral, with Thenardite, Trona and Glaserite following, respectively. Halite will be best extracted at higher temperatures whereas the lower temepratures will favour sulphate based minerals.