Wetting, Spreading and Penetration Phenomena of Slags on MgAl2O4 Spinel Refractories

The wetting, spreading and penetration phenomena between slags and refractories were investigated by using a dispensed drop technique with a high speed camera (1 000 frame/s) at 1 923 K and 1 873 K and using non-saturated slag and saturated slag on MgAl2O4 spinel. Single crystal spinel was adopted as a substrate to determine the intrinsic values associated with the phenomena including dissolution reaction. Industrial spinel substrates with 35% apparent porosity such as MgO-rich spinel, stoichiometric spinel and Al2O3-rich spinel were used to study the influence of chemical composition and porosity of refractories on those phenomena. In case of the stoichiometric spinel, the values of apparent contact angle and droplet height were found lower in comparison with single crystal spinel. When MgO and Al2O3 content were added to the spinel, the MgO-rich spinel appeared to have larger permeability of slag. On the other hand, the Al2O3-rich spinel showed larger resistance to slags. The change of apparent volume of slag in contact with substrate was analyzed using a spherical cap model. The experimental values of the spreading rate of non-saturated slag are in good agreement with the value of the De-Gennes's theoretical model.