X-ray and neutron Rietveld quantitative phase analysis of industrial Portland cement clinkers

Artikel i vetenskaplig tidskrift, 2004

Weight fractions of four dominant phases (C3S, C2S, C4AF, and C3A) present in five industrial clinkers were estimated by a series of neutron and X-ray Rietveld refinements. Calculated powder patterns were derived from the structural data for monoclinic and triclinic C3S, monoclinic C2S, orthorhombic C4AF, cubic C3A and MgO. Neutron diffraction data were collected with the high resolution E9 diffractometer (BENSC) using two different wavelenghts, X-ray diffraction data with a high resolution transmission diffractometer. Elemental composition of the samples obtained by ESEM/EDX technique were in good agreement with the data delivered by the producers. Convergence of the refinements was remarkably different for X-ray and for neutron data. Several refinements were not completed due to numerical instabilities. Neutron refinements were found to be more stable tha X-ray, but there was not any notable difference in the final estimated phases' compositions. Calculated absolute deviates of phases' weight fractions were mostly within +-10%, which for the less abundant phases corresponded to relative deviations within +-50%.