Process for forming a coherent refractory mass on a surface

A ceramic welding process for forming a coherent refractory mass on a surface of a refractory, which refractory is comprised of at least one silicon compound, the process comprising:

• (a) providing a mixture comprised of:
• (1) combustible particles including silicon particles,
• (2) refractory particles of at least one refractory substance selected from the group consisting of silicon carbide particles and silica particles, which refractory particles constitute a major portion by weight of the mixture, and
• (3) particles of a non-metallic precursor of another substance selected from the group consisting of CaO, MgO, FeO, and mixtures thereof, which another substance causes incorporation of silica, formed by combustion of the silicon particles, into a crystalline lattice of a compound formed between the silica and the another substance within the coherent refractory mass being formed;
• and
• (b) projecting the mixture against the surface of the refractory, simultaneously with substantially pure oxygen, so that the combustible particles react in an exothermic manner by combusting with the projected oxygen and release sufficient heat to form the coherent refractory mass under action of heat of combustion, and so that silica, formed by combustion of the silicon particles, is incorporated into the crystalline lattice of a compound formed between the silica and the another substance,
• wherein the particles of a non-metallic precursor of another substance are selected from the group consisting of wollastonite (CaO.SiO.sub.2), a peroxide, a nitride, and a carbide.