Experimental investigation and thermodynamic modelling of the BaO-MgO system

摘要

BaO-bearing slags have attracted attention in slag chemistry largely because of refining ability for desulfurization and dephosphorization as well as a component of non-ferrous refining slags. The phase relations of BaO with other components, CaO, MgO, Al_2O_3 and SiO_2, have been scarcely reported due to the difficulties such as, high experimental temperature (above 1673 K), sensitivity of BaO to humidity and formation of BaO_2 at low temperatures. Investigation of the thermodynamic stabilities and phase diagrams of the BaO-containing systems contribute to a better understanding of slag chemistry and expand the Mtox slag database.In the present work, the phase equilibria of the BaO-MgO system was experimentally studied ranging from 1673 K to 1873 K by high temperature equilibration, quenching, Scanning Electron Microscope (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDS). The thermodynamic evaluation was performed employing Thermo-Calc packages. A set of consistent thermodynamic parameters was achieved explaining most of the experimental data. The calculated phase diagram of BaO-MgO system compared with present experimental observations and literature data was provided. The enthalpy of mixing of liquid at 1523 K was calculated.