A method for lining metallurgical vessels used in foundries or steelworks with a self-hardening refractory composition, comprising the following steps: a) applying the self-hardening refractory composition to the floor of the metallurgical vessel, b) placing a mold around the safety walls of the metallurgical vessel; c) filling in the space between the mold and the safety lining with the self-hardening refractory composition, and d) removing the mold, wherein the self-hardening refractory composition comprises: • at least one granulated solid material selected from among: olivine, quartzite, alumina, and a dead-burned mineral selected from the list comprising brucite, dolomite and magnesite, preferably the granulated solid material is a dead-burned magnesite, • a liquid binder of inorganic nature, wherein the liquid binder of inorganic nature is liquid sodium silicate in a proportion of between 4.5 and 6.5 % by weight with respect to the granulated solid material, or a liquid binder of organic nature, wherein the liquid binder of organic nature is a phenol/formaldehyde resin in a molar ratio of phenol/formaldehyde of between 0.4:1 to 0.6:1, and • a liquid additive, in a percentage by weight of between 15 and 20 % by weight with respect to the liquid binder, which is a glycerin-based ester; and wherein the self-hardening refractory composition is mixing at room temperature by means of a mixer, into which each one of the components forming the composition is placed separately. a) applying the self-hardening refractory composition to the floor of the metallurgical vessel, b) placing a mold around the safety walls of the metallurgical vessel; c) filling in the space between the mold and the safety lining with the self-hardening refractory composition, and d) removing the mold, wherein the self-hardening refractory composition comprises: • at least one granulated solid material selected from among: olivine, quartzite, alumina, and a dead-burned mineral selected from the list comprising brucite, dolomite and magnesite, preferably the granulated solid material is a dead-burned magnesite, • a liquid binder of inorganic nature, wherein the liquid binder of inorganic nature is liquid sodium silicate in a proportion of between 4.5 and 6.5 % by weight with respect to the granulated solid material, or a liquid binder of organic nature, wherein the liquid binder of organic nature is a phenol/formaldehyde resin in a molar ratio of phenol/formaldehyde of between 0.4:1 to 0.6:1, and • a liquid additive, in a percentage by weight of between 15 and 20 % by weight with respect to the liquid binder, which is a glycerin-based ester; • at least one granulated solid material selected from among: olivine, quartzite, alumina, and a dead-burned mineral selected from the list comprising brucite, dolomite and magnesite, preferably the granulated solid material is a dead-burned magnesite, olivine, quartzite, alumina, and a dead-burned mineral selected from the list comprising brucite, dolomite and magnesite, preferably the granulated solid material is a dead-burned magnesite, • a liquid binder of inorganic nature, wherein the liquid binder of inorganic nature is liquid sodium silicate in a proportion of between 4.5 and 6.5 % by weight with respect to the granulated solid material, or a liquid binder of organic nature, wherein the liquid binder of organic nature is a phenol/formaldehyde resin in a molar ratio of phenol/formaldehyde of between 0.4:1 to 0.6:1, and • a liquid additive, in a percentage by weight of between 15 and 20 % by weight with respect to the liquid binder, which is a glycerin-based ester; and wherein the self-hardening refractory composition is mixing at room temperature by means of a mixer, into which each one of the components forming the composition is placed separately.