Abstract:Slag movement on SiO₂-based prism refractories in different slag systems was observed. The cross section shape evolution mechanism was discussed. Two types of shape evolution appear. For PbO-SiO₂ slag whose surface tension improves with SiO₂ concentration, slag film flows up along four edges under axial Marangoni shear force and wettability. Then, it flows down along four lateral faces under gravity. Corrosion rate at edges is larger than that on lateral faces due to different SiO₂ solubilities of ascending and descending flow. Prism cross section shape changes from square to round. For Fe_tO-SiO₂ slag whose surface tension reduces with the increase of SiO₂ concentration, slag film flows up under the inflence of wettability. Then, it flows down under Marangoni shear force and gravity. Compared to four edges, slag is mainly up and down on four lateral faces due to larger surface tension and size. So, prism cross section shape keeps square.

Key words: Marangoni convection; slag film; local corrosion; solid-liquid-gas interface; SiO₂-based refractories