Smelting apparatus comprises a vessel (11) and a solids injection lance (27a) extending through an opening in the wall of vessel barrel (16) into the interior space of the vessel. Lance (27a) includes a central core tube (31) through which to pass solid particulate material into the vessel and an annular cooling jacket (32) surrounding the central core tube (31) throughout a substantial part of its length. Lance (27a) has a mounting structure (61) comprising a tubular part (60) extended about cooling jacket (32) and about twice the diameter of the cooling jacket. Tubular part (60) fits within a tubular lance mounting bracket (62) welded to the shell (16a) of vessel barrel (16) to extend outwardly from the vessel. The lance is held within mounting bracket (62) by clamping bolts acting between flanges (63,65) on tubular part (60) and tubular bracket (62). Tubular part (60) is double walled and the interior space between its walls is divided into water flow passages through which cooling water flows from a water inlet (68) to an outlet (69).