Modern spinel-containing refractories (neglecting MK chromium spinels) can be
classified into the following main types: (1) MgO–Al2O3 refractories (including
MgO–MA, pure MA, and Al2O3–MA); (2) MgO–Al2O3–TiO2 refractories
(including, e.g., MgO–MA–MgTi2O4 and Al2O3–MA–Al2TiO5); (3) MgO–
Al2O3–ZrO2 refractories (including MgO–MA–ZrO2 and Al2O3–MA–ZrO2);
(4) MgO–Al2O3–SiO2 (including, e.g., MA–M2S and MA–A3S2) refractories;
(5)MgO–Al2O3–CaO refractories (including, e.g.,MA–CA6) and (6)MA–carbon
refractories (including, e.g., MA–SiC–C, Al2O3–MgO–C, and MgO–Al2O3–C)