Dissolution of MgO·Al2O3 spinel and MgO in CaO-Al2O3-MgO-SiO2 slag under forcedconvection

In this work, the dissolution mechanism of dense MgO·Al2O3 spinel and MgO rod into molten CaO-Al2O3-MgO-SiO2 slag was investigated at 1873 K with forced convection. The dissolutionexperiments were carried out by employing a newly developed rotating cylinder method. The effect of rotation speed and reaction time on the dissolution rate was studied. The measured dissolution rates of both spinel and MgO were dependent on the rotation speed, indicating that mass transfer in the slag phase to one of the rate-limiting steps. It was also found that the dissolution rate of spinel in slag was enhanced more rapidly than that of MgO with the increasing reaction time and rotation speed. It was also found that the composition of the slag at the interface was far from equilibrium value between the slag and solid. The results implied that the chemical reaction at the solid-slag interface should be the other important step that jointly controlling the dissolution process.QC 20170918European Union’s Research Fund for Coal and Steel (RFCS) research program under grant agreement No RFSR-CT-2015-0000