Effect of the addition of iron oxide on the microstructure of ye'elimite

• Published in: Cement and concrete research Vol. 151; p. 106625
• Main Authors: Abir, F.Z., Mesnaoui, M., Abouliatim, Y., Nibou, L., Labbilta, Tariq, El Hafiane, Y., Smith, A.
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.01.2022; Elsevier BV; Elsevier
• Subjects: Aluminum oxide; Calcium aluminate; Calcium aluminum ferrite; Chemical Sciences; Diffusion rate; EDS mapping; Ferritic phase; Grains; Iron oxides; Liquid phases; Microstructure; Morphology; Thermal treatment; Ye'elimite; Ferritic phase; Microstructure; Ye'elimite; EDS mapping; Thermal treatment
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2021.106625

This article is devoted to the description of the microstructure of ye'elimite, calcium aluminates and ferritic phase when iron oxide is present and when the synthesis is carried out at 1300 °C for 3 h. The incorporation of iron in ye'elimite structure (general formula: Ca4Al(6-2x)Fe2xSO16 with x = 0.00 to 1.13) is complete when x < 0.12. Beyond this composition, the ferritic phase (CaO)2(Al2O3,Fe2O3) appears as a minor phase which can develop two forms: needle-like morphology and melt morphology. The presence of iron favors the formation of an iron-rich liquid phase which leads to the growth of ye'elimite grains by material diffusion mechanisms and increases the conversion rate of alumina and calcium aluminates in ye'elimite phase. Also a clear distinction between calcium aluminate and ye'elimite grains is presented. •Complete and detailed description of microstructure of ye'elimite containing iron; general formula: Ca4Al(6-2x)Fe2xSO16 with x = 0.00 to 1.13•The incorporation of iron is complete when x < 0.12.•Beyond this composition, the ferritic phase (CaO)2(Al2O3,Fe2O3) appears as a minor phase which can develop two forms: dendritic morphologies and melt morphology.•A clear distinction between CA and ye'elimite grains has been reported for the first time.•The presence of iron favors the formation of an iron-rich liquid phase, which leads to the formation of larger ye'elimite grains, through a liquid phase reactive sintering.