Rebonded fusion-cast AZS refractory grain

Fired refractory article having a fourphase micro-structure of corundum, badeleyite mullite and glassy phase with the mullite being about 5-25 wt.% thereof and the glassy phase being about 5-20 vol.% thereof, the article being a sintered refractory composition consisting of:

• (A) 25-60 wt.% fusion-cast alumina-zirconia-silica refractory coarse grain being at least 89 wt.% -6+20 Tyler mesh,
• (B) 0-38 wt.% fusion-cast alumina-zirconia-silica refractory medium grain being at least 73 wt.% -10+35 Tyler mesh,
• (C) 30-50 wt.% at least one component selected from the group consisting of
• (1) 0-50 wt.% fusion-cast alumina-zirconia-silica refractory fine grain being at least 60 wt.% -35+325 Tyler mesh, and
• (2) 0-30 wt.% at least one constituent selected from the group consisting of
• (a) alumina being at least 90 wt.% -325 Tyler mesh, at least 98.5 wt.% Al.sub.2 O.sub.3 and not more than 0.5 wt.% Na.sub.2 O, and
• (b) -325 Tyler mesh chromic oxide being at least 95 wt.% Cr.sub.2 O.sub.3, and
• (D) 0-7 wt.% colloidal silica, the fusion-cast alumina-zirconia-silica refractory having:
• (i) a three-phase microstructure of interlocking crystals or corundum phase and baddeleyite phase with intercrystalline glassy phase therebetween, the glassy phase being about 15-30 vol.% of the alumina-zirconia-silica refractory, and
• (ii) an oxide analysis consiting of 35-60 wt.% Al.sub.2 O.sub.3 plus Cr.sub.2 O.sub.3 with Cr.sub.2 O.sub.3 .ltoreq. 60 wt.% of Al.sub.2 O.sub.3 plus Cr.sub.2 O.sub.3, 25-50 wt.% ZrO.sub.2, 10-18 wt.% SiO.sub.2, 0.8-1.8 wt.% Na.sub.2 O plus K.sub.2 O, and up to 0.7 wt.% other ingredients.