Unshaped refractory compositions useful as jointing and moulding compositions

An unshaped refractory composition which consists essentially of by weight:

• (a) 55 to 99% of particles of a fused cast refractory material which contains a vitreous phase and the composition of which consists essentially of, as main constituents, ZrO.sub.2, Al.sub.2 O.sub.3 and SiO.sub.2, or ZrO.sub.2, Al.sub.2 O.sub.3, SiO.sub.2 and Cr.sub.2 O.sub.3 ;
• (b) 1 to 4% of a hydraulic cement;
• (c) 1 to 15% of a filler consisting of very fine, substantially spherical particles of a metal oxide selected from the group consisting of vitreous silica, alumina, chromic oxide (Cr.sub.2 O.sub.3) and zirconia, the surface area of these particles being higher than 5 m.sup.2 /g;
• (d) 0 to 25% of fine particles of a size less than 40 microns selected from the group consisting essentially of particles of zirconia, alumina, chromic oxide Cr.sub.2 O.sub.3, fused cast refractory products the chemical composition of which comprises by weight 75-85% ZrO.sub.2, 2-8% SiO.sub.2, 9-17% Al.sub.2 O.sub.3, 0.5-0.7% of other oxides, and mixtures thereof;
• the proportion of each of the constituents (a), (b), (c) and (d) being given with respect to the total of the ingredients (a), (b), (c) and (d);
• and
• (e) 0.01 to 1% of a surface-active agent, the amount being with respect to the total weight of the constituents (a), (b), (c) and (d), said surface-active agent imparting a Newtonian behavior to the composition.