Investigation of CaO/MgO on the formation of Anorthite, Diopside, Wollastonite and Gehlenite phases in the fabrication of fast firing ceramic tiles: Fid-Bau Portal

Investigation of CaO/MgO on the formation of Anorthite, Diopside, Wollastonite and Gehlenite phases in the fabrication of fast firing ceramic tiles

Hosseiny, Amir Hossein Mahmoud / Najafi, Abolhassan / Khalaj, Gholamreza

Abstract

Highlights • In the current research, the following items were studied. • The mineral phases of fast firing ceramic tiles. • The ratio CaO/MgO and its contribution on the phase transformation during fast firing of ceramic tiles application. • The impact of fine-grind calcium carbonate and Talc A were also surveyed on the final microstructure. • The testing methods and the detailed structure of the manuscript revealed a research that will contribute to the ceramic tiles industry.

Abstract In this research, the effect of CaO/MgO ratio as the principal oxides activating reactions during fast firing of ceramic tiles on the transformations and formation of phases such as Anorthite, Diopside, Wollastonite, and Gehlenite was studied. Calcium carbonate and Talc/dolomite powder were selected as the sources of CaO and MgO, respectively. After forming with the press, the mixtures were dried, and the bodies were sintered. XRD, XRF, Dilatometry, and SEM/FESEM analysis methods were used to study the microstructural transformations, chemical and physical reactions in the microstructure, and final physical properties of the samples. The X-ray diffraction test identified the phases of the constructed bodies. The weight percentage of the constituent phases was calculated using the MAUD software. Studies indicated that the weight percentage of the Anorthite phase increased by decreasing the CaO/MgO ratio. In addition, the thermal expansion coefficient decreased with the reduction of the CaO/MgO ratio. The lowest coefficient of thermal expansion (7.69 × 10^-6 (1/°C)) was reported. Microstructural studies demonstrated that the harmful phase of Gehlenite was removed from the final microstructure, and the Anorthite phase was increased (up to 10 wt%) by fine-graining the primary sources of calcium carbonate and Talc. Furthermore, crystals of the Anorthite phase grew more.