The value of the porous heat-insulation refractories continues to increase [1][2][3][4]. Foam ceramic of a mullite composition appears to be a promising material but we have seen no published reports on production or property data.We have studied how to obtain mineralized foams from suspensions of a mullite composition [5] and have done research on the optimum formation conditions and on some of the properties of the material after sintering. The suspensions had a polydispersed composition and contained* 32% of fractions finer than 3 ~m; 11% of 3-5 #m; 21%, 5-10 ~m; 30% 10-20 #m; and 6?0, coarser than 20 vm. The concentration of a previously stabilized, untreated suspension of density 2.08 g/cm 3 and pH 3.20 was adiusted by dilution with water~ In order to obtain three-phase foams (foam masses), the suspensions were mixed with two-phase foams with a glue-resin foaming agent whose properties have been already studied in [6]. the volume shrinkage on molding ShV~ and the foam ceramic sintered ,qhtot. at 1480~ (total shrinkage -"V ' the apparent density Papp, the total porosity Ptot; and the ultimate compressive stress o comp) ; Vf/Vs = 4.5. Fig. 2. Dependence of the log viscosity ~ and the shear velocity ~ on the shear stress P of the aqueous suspension of mullite with C V = 0.40 (1); the two-phase foam with Cg = 0.95 (2); and the three-phase mineralized foams obtained from them with K V equal to 2.84 (3); 5.6 (4); 8.5 (5); and 11.4 (6).

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