Mineralogical and Chemical Comparison of Carbonate From Sites Selected for Artisanal Cement Production With Limestone Used in Commercial Operations

Abstract

The present mineralogical and chemical related study, as based on a selection of carbonate-rock-deposit samples extracted from South African sites, is aimed to test these materials’ suitability for producing cement, necessary for the achievement of local infrastructure projects. The sites are located on the Rietfontein, Rooikop and Wiedouw farms. The study has been implemented via petrographic, X-Ray Diffraction and X-Ray Fluorescence techniques. The reached results reveal that the Rietfontein material to be composed of calcrete, while that extracted from the Rooikop site is composed of recycled micrite. At Wiedouw, the carbonate turns out to be a low metamorphic grade marble with classic metamorphic polygonal grains and grain boundaries. The undertaken experiments prove that, thanks to their purity, the selected sites’ available carbonate material is suitable not only for cement manufacture, but also for the production of calcium oxide for use in various industrial processes requiring high-grade lime or limestone. Future development should, therefore, consider exploitation of these deposits as raw material sources fit for cement as well as limestone and lime production. Noteworthy, however, is that while the Wiedouw marble and the Rooikop limestone prove to constitute compact and tough rocks, requiring higher costs for blasting, crushing and grinding for the small quarry, the Rietfontein calcrete turns out to be softer and, therefore, highly preferred in respect of the former two materials.