Mineralogical and chemical comparison of carbonate from sites selected for cement production with limestone used in commercial operations

This is a mineralogical and chemical study of samples from selected carbonate rock deposits in South Africa, to test their suitability for the production of cement for local infrastructure projects. The sites are located on Rietfontein, Rooikop, and Wiedouw farms. The study has been carried out using petrographic, X-ray diffraction, and X-ray fluorescence techniques. The results show that material from Rietfontein is composed of calcrete, while that at Rooikop is composed of recycled micrite. At Wiedouw, the carbonate is a low metamorphic grade marble with classic metamorphic polygonal grains and grain boundaries. The study shows that the carbonate material from the selected sites is suitable, not only for cement manufacture but, due to their purity, 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 for cement production, as well as limestone and lime production. While the Wiedouw marble and the Rooikop limestone form compact and tough rocks requiring higher costs for blasting, crushing, and grinding for the small quarry, the Rietfontein calcrete, being of secondary surface origin, is softer and is therefore preferred ahead of the other two.