Processes for working-up an aqueous fluosilicic acid solution

South African Journal of Science

Field Value
Title Processes for working-up an aqueous fluosilicic acid solution
Creator Toure, Alpha O. Sambe, Falilou M. Koita, Démo Diop, Codou M.G. Sock, Oumar
Subject Chemical and Environmental Engineering caustic soda; caustification; ethanol; precipitation; sodium chloride
Description Aqueous fluosilicic acid solutions were once considered to be only adverse by-products of phosphoric acid production, which required treatment to prevent ecosystem destruction when discharged into the sea. However, a range of chemicals can be generated by the transformation of this industrial waste product. Through experiments undertaken in the laboratory, we have shown the possibility of caustic soda production. Volumetric analysis showed caustic soda to be present as a 6% – 7% solution with yields of about 70% – 80% by weight. Two processes were investigated for the caustification of sodium fluoride, using different precipitates: sodium chloride and ethanol and are described by modelling caustification curves. The activation energies of precipitation determined by semi-empirical correlations showed that precipitation by ethanol (EA = 933.536 J/mol) was more successful than precipitation by sodium chloride(EA = 7452.405 J/mol). Analyses performed on the precipitates highlighted compositions that are essential and useful constituents in the cement industry.
Publisher AOSIS
Date 2012-11-02
Type info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion — —
Format application/pdf text/html application/octet-stream text/xml
Identifier 10.4102/sajs.v108i11/12.919
Source South African Journal of Science; Vol 108, No 11/12 (2012); 5 pages 1996-7489 0038-2353
Language eng
Coverage — — —
Rights Copyright (c) 2012 Alpha O. Toure, Falilou M. Sambe, Démo Koita, Codou M.G. Diop, Oumar Sock