Comprehending the occupying preference of manganese substitution in crystalline cement clinker phases: A theoretical study

Understanding the dopant behavior in cement clinker has been an important issue due to the increasing use of alternative fuels and secondary raw materials for cement manufacturing following the rising demand for reduction of CO2 emissions and energy consumption. In this work, state-of-the-art ab initio calculations have been employed to systematically investigate manganese (Mn) doping mechanism in four dominant clinker phases. Corresponding experimental studies are incorporated to verify simulated results. A conspicuous preference of Mn for occupying the Fe site in ferrite is found based on formation energy analyses, which is in accord with our experiments and vast literatures. More in-depth analyses indicate the Mn doping mechanism follows the electronic structure matching principle, which influences the stability of doped structures by inducing localized coordination distortions. The work provides a fundamental perspective to investigate doped clinker, which facilitates the searching for other doping species, thereby designing steerable doping-enhanced cement.