PURPOSE: To improve hardening reaction rate by blending a main material comprising an aqueous solution of an alkali metal silicate, an inorganic solid component and a filler in a specific weight ratio with a given amount of soft- burned Cab.

CONSTITUTION: An aqueous solution (A) of an alkali metal silicate having 1.0-3.0 molar ratio of SiO2 and K2O and/or Na2O and 30-60wt.% concentration is prepared. An inorganic solid component (B) comprising 2-98wt.% SiO2 such as corundum furnace dust and 98-2wt.% Al2O3, a filler (C) such as silica and softened CaO (D) having ≥80wt.% particles with ≥100μ particle size and ≥500 degree of activity are prepared. Then in order to make 100 pts.wt. components (A)+(B)+(C) and 1-10 pts.wt. component (D), first 15-70 pts.wt. component (B) is mixed with 10-65 pts.wt. component (C) and 1-10 pts.wt. component D and then with 20-70 pts.wt. component (A) to give a composition for an inorganic molded article. The composition is fed to a mold, hardened at 50-100°C for a given time to give an inorganic molding having high bending strength free from cracks.