Iraqi National Journal of Earth Science

Abstract

The limestone of Jeribe Formation in Bekhair anticline, Duhok Governorate, was assessed as raw materials for the Ordinary Portland Cement (OPC) industry. Four sections were selected; the formation consists of fossiliferous limestone and thin layers of dolomitic limestone. The petrographic study showed that the main mineral of limestone rocks is fine calcite with a size less than 0.25 cm. The chemical analysis revealed that the mean concentration of CaO is 51.77% which dominates over other oxides, including MgO (2.06%), SiO2 (1.95%), Al2O3 (0.60%), and, Fe2O3 (0.22%), While the remaining oxides (K2O, Na2O, TiO2, MnO, P2O5, and SO3) are present in traces. The lime saturation factors (LSF) of the studied sections range from (1651.70 to 2334.89), which are over the limits necessary for high-quality cement; thus, a claystone rock from the Fatha Formation was added to achieve the best point of clinker LSF. The physical and mechanical tests of samples indicate low porosity, and the compressive strength range between (168-1291 kg/cm²), which are acceptable for the cement industry and make the rocks easy to crush and grind during the preparation of the mixture. According to the results of the analyses, we conclude that the mixture of limestone ranges between (65.9-69.3) and claystone ranges between (30.7-34.1) in the study area are of good quality and meet international standards for ordinary portland cement.