the refractories may also dissolve in the slag in three ways: (1) reaction with slag
FexO and MnO to form a complex spinel (Mg,Mn,Fe)(Al,Fe)2O3 and thus dissolve
into the slag; (2) reaction with slag CaO to form low-melting calcium aluminates;
and (3) reaction with slag CaO and SiO2 to form low-melting CAS phases such as
C2AS and CAS2, so the MA dissolves directly in the slag.