Geochemistry and mineralogy of the sebkha Oum El Khialate evaporites mixtures, southeastern Tunisia

Abstract

This work is meant to study the variation of geochemistry and mineralogy of three salts recuperated from brines of the sebkha Oum El Khialate based on XRF, X‐ray diffraction (XRD), and Fourier transform infrared (FTIR) analyses. Elemental analyses indicate enrichment with major element having an economic interest such as potassium. Compared to standards, minor elements analyses yield high concentrations of hazardous elements such as Cd and Cr, and represent a threat for human consumption. XRD and FTIR analyses display a variable mineralogy along the evaporation path including minerals that are specific for this sebkha, such as vaterite (CaCO3), potassium pentasulphate (K2S5O16), thenardite (Na2SO4), beryllium sulfate (BeSO4), brucite (Mg(OH)2), and mirabilite (Na2SO4·10 H2O). The geochemistry and mineralogy of recuperated salts prove the relevance of the sebkha Oum Khialete as a potential ore resource to be used in industry and agriculture.