Stratigraphic and Mineralogical Study of Chouabine Formation in the Meknassy Basin (Central Tunisia)

Abstract

A 39-m thick phosphate rock was subdivided into 8 layers based on facies changes. The mineralogical composition of these layers was investigated using XRD and binocular loupe. The result appeared to reveal that the layers prove to contain carbonate-fluorapatite, quartz, calcite, gypsum and dolomite, in proportions that vary from a layer to another. This variation is also persistent in the implemented chemical analyses. A simple washing was carried out to obtain a commercial phosphate. The phosphorus pentoxide content (29.41%) in the layer CIII₄ turns out to be high enough that it does not require further treatment. Noteworthy, however, is that it appears economically interesting to mix layer CI₁ (26.58% P₂O₅) with layer CIII₄ for a 28.77% phosphorus pentoxide content to be attained.