On the variability of industrial Portland cement clinker: Microstructural characterisation and the fate of chemical elements

Portland cement (PC) has been used and developed since the early 19th century. Although the compositional ranges of PC clinkers are generally specified in standards, there is a lack of information on the variability of industrial clinkers. Furthermore, with an increase in the use of alternative mineral and fuel feeds, it is important to understand the evolution of clinker chemistry and mineralogy which affects hydraulic reactivity. In this work, 27 clinkers, selected to span the limits of clinker manufacturing, are characterised using X-Ray fluorescence (XRF), X-Ray diffraction (XRD), and scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDX). These are compared against clinker data from literature, which provides a comparison between modern clinkers and historical clinkers analysed over 50 years ago. Finally, the clinker datasets are used to carry out and compare different calculation methods including Bogue, modified Bogue, and Gibbs energy minimisation using a published stoichiometric thermodynamic database.