Influence mechanism of additives on the crystal structure and desulfurization performance of magnesium slag

Abstract

In this thesis, three additives, BaO, B2O3 and P2O5, were added to modify the original magnesium slag in the process of quenching hydration of magnesium slag. The crystal phase composition, crystal structure parameters and crystal morphology of different modified magnesium slags were studied by various characterization analysis methods. Combined with the corresponding calcium conversion rate of the samples, the influence mechanism of different additive modification conditions on the desulfurization performance of magnesium slag was obtained. The results showed that the incorporation of BaO, B2O3 and P2O5 could inhibit the nucleation of γ-C2S and prevented the crystal phase transformation of β-C2S during cooling, thus increasing the content of β-C2S with high activity. Among them, MS-950–4% BaO desulfurizer had the best adsorption effect. The β-C2S content, lattice distortion and calcium conversion rate of the samples were 49.6%, 0.057% and 29.8%. The higher activity of β-C2S could generate C–S–H through hydration and then enhanced the physical adsorption capacity of magnesium slag; the increase in crystal structure defects could enhance the chemical adsorption capacity of magnesium slag, so as to improve the overall adsorption capacity of magnesium slag, and then improved the desulfurization performance of magnesium slag. The influence of chemical adsorption capacity on desulfurization performance was greater than that of physical adsorption capacity.