Abstract
Keeping a low and steady viscosity of slag is conducive to smooth operation of blast furnace. In this work, the effect of BaO on the viscosity and structure evolution of CaO–SiO 2 –MgO–Al 2 O 3 –BaO slag with a fixed CaO/SiO 2 mass ratio of 0.9 was studied. The results revealed that the viscosity decreased firstly with BaO content rising from 0 wt% to 1.0 wt%, and then increased with further improving BaO content, which was ascribe to the contradictory effect of Ba 2+ and O 2− on the aluminate–silicate network structure. The structural analysis by Fourier transform infrared spectroscopy (FTIR) and Raman spectra showed that a small amount addition of BaO could promote the transformation from Q 2 and Q 3 units toward Q 0 and Q 1 units. However, the higher BaO content would induce an increasing concentration of Q 2 and Q 3 units, leading to an enhancement of the polymerization degree of slag. In addition, the variations of Al-related structural units were identified by the 27 Al magic angle spinning nuclear magnetic resonance ( 27 Al MAS-NMR) spectra. The relative fraction of [AlO 4 ] units firstly decreased and then increased with the addition of BaO, and an opposite trend was observed for [AlO 5 ] and [AlO 6 ] units. The structural analysis supported the results of viscosity experiment well.
Published Version
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