A Study on the Production of Low-heat Cement Using Non-carbonate Raw Materials with 5% Substitution of Limestone

Abstract

This study aims to produce low heat cement by substituting limestone, the main raw material of cement, with non-carbonate raw materials for 2050 carbon neutrality. The use of non-carbonate raw materials can reduce CO₂ generated by the calcination of limestone and reduce the amount of energy required for the calcination. The non-carbonate materials reviewed in this study are BOF slag, KR slag, and blast furnace slag with a CaO content of more than 40%. Compared to limestone, non-carbonate materials have lower grindability and higher Fe₂O₃ and Al₂O₃ content, which limits their ability to substitute limestone. By applying the chemical composition of non-carbonate raw materials and applying a low heat cement modulus to calculate the clinker raw material mixture, it was possible to calculate a raw material mixture that substitutes 5% limestone. The raw materials were mixed in the laboratory, fired to produce clinker, and mixed grinding of the fired clinker and gypsum to produce low-heat cement. The chemical and physical properties of the cement produced using the non-carbonate raw materials were evaluated and found to meet the KS standard. In the future, the use of non-carbonate raw materials to substitute limestone is expected to contribute significantly to the reduction of CO₂ emissions in the cement industry.