Inhibitor effect of selected anionic surfactants on the dissolution of calcium sulfate in aqueous brines

Cristiana Damasceno; Maria de Fátima Machado da Costa; Maria de Lourdes dos Santos Serrano; M.F.C. Pereira

Key information

Authors:

Cristiana Damasceno (Cristiana Damasceno Loureiro); Maria de Fátima Machado da Costa (Maria de Fátima Machado da Costa Farelo); Maria de Lourdes dos Santos Serrano (Maria de Lurdes Dos Santos Serrano); M.F.C. Pereira (Manuel Francisco Costa Pereira)

Published in

September 2008

Abstract

Leaching of halite from mineral deposits by solution mining is a technology with worldwide application. For the salt industry, only the valuable components in the mineral deposit must be dissolved and removed to the surface for further processing. Inevitably, several minor impurities, such as calcium sulfate minerals, are also leached and the out-coming contaminated brine must be subject to costly purification treatments. Therefore, the inhibition of the dissolution of calcium minerals is a subject with scientific interest and potential economic impact. The dissolution of anhydrite in saturated brines of sodium chloride may be inhibited by the presence of water-soluble macromolecules, being the effectiveness of the inhibitor evaluated from the degree of coverage of the target surface and the desorption resistance. The ideal macromolecule, besides being selective towards anhydrite, should not harm the morphologic characteristics of the main salt in downstream crystallizations. In this study, the influence of some selected anionic surfactants on the solubility of gypsum, anhydrite and anhydrite-rich sediments in concentrated brines was investigated.