Reaction monitoring of cementing materials through multivariate techniques applied to time-resolved synchrotron x-ray diffraction data

In this work, the setting reaction of magnesium potassium phosphate ceramic (MKPC) from magnesia (MgO) and potassium di-hydrogen phosphate was investigated by means of in-situ synchrotron X-ray powder diffraction (XRPD). The experimental data were analyzed through multivariate statistical techniques that enabled a real time and reliable understanding of the phenomena occurring in the process. Here, a method combining Multivariate Curve Resolution - Alternating Least Squares (MCR-ALS) with Evolving Factor Analysis (EFA) was proposed. Comparison with the conventional methods showed that the compounds involved in the process can be correctly distinguished and the main reaction steps, such as reactants consumption, occurrence of intermediate amorphous phase and MKPC formation can be clearly identified.