Experimental investigation of pore structure during high sodium coal ash sintering with and without calcium oxide additive through XCT technology

Abstract This article investigates the evolution of morphology and pore structure during sintering at 1200°C for a high sodium coal ash, with and without using a calcium oxide additive. The effect of different proportions of calcium oxide additive was studied. The ratios of height and area of samples were calculated, and representative sintering time points of morphological changes were captured. Meanwhile, frequencies of diameter, pore numbers, and porosities were obtained by processing images. The maximum ratio of height and area reached at 15 min, 4 min, and 10 min for the sintering process of coal ash sample without additive, with 5% and 10% CaO, proving that CaO accelerates the sintering process. In comparison, the maximum porosities were 52.4%, 39.5%, and 47.0% for sintering samples after 10 min, 6 min, and 40 min. Besides, X‐ray diffraction analysis of the minerals of the condensed white matter was conducted.