Substantially dry, self-hardening, thermally activated refractory compositions, suitable for use to produce linings for furnaces or metallurgical vessels such as ladles, tundishes or launders, comprise particulate refractory material, an inorganic binder having associated therewith chemically or physically bound water such as sodium metasilicate pentahydrate or tribasic sodium phosphate dodecahydrate, and an element or compound, such as aluminium, which will react exothermically with the inorganic binder. The compositions may also contain an inhibitor such as a mineral oil or a vegetable oil to inhibit premature exothermic reaction.