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IJSTR >> Volume 7 - Issue 11, November 2018 Edition

International Journal of Scientific & Technology Research  
International Journal of Scientific & Technology Research

Website: http://www.ijstr.org

ISSN 2277-8616

Thermodynamic Modeling Of Lake Katwe Brine For Industrial Salt Production

[Full Text]



Joseph Ddumba Lwanyaga, Hillary Kasedde, John Baptist Kirabira



Evaporation, Lake Katwe, Mineral Salt, Phase Chemistry, PHREEQC, Saturation Index



Extraction of commercial mineral salts from the lake brine requires thorough knowledge of the brine phase chemistry. In this paper a solubility software (PHREEQC) has been used to predict which salts, their respective yield and the order in which they can crystallize from Lake Katwe brine. The brine solution was evaporated to supersaturation by removing 51 moles of water at 27.6°C. Thereafter, supersaturated solution was subjected to temperature variations ranging from -30° to 130°C. After removal of 31 moles of water, Thenardite equilibrates with the solution followed by Trona (33 moles), Burkeite (35.5 moles), Halite (36 moles) and lastly Glaserite (41.5 moles). At subzero temperatures, Mirabilite emerged with the highest Saturation Index (SI) followed by Sylvite and Halite. During evaporation, the PHREEQC model predicts a mineral precipitation sequence that starts with Thenardite followed by Trona, Burkeite, Halite and Glaserite. Based on the yield results, Halite, Thenardite, Burkeite, Glaserite, and Trona are the feasible salts that can be extracted, the latter being the least feasible. The ideal parameter ranges of pH, alkalinity, temperature, brine concentration factor and ionic strength were determined.



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