A smelting unit for steel production with a tap weight of between 60 t and 350 t and a method for operating the same are disclosed. By a top lance that moves during operation of the smelting unit and the coordinated injection of process gases by sidewall injectors and the top lance, the undulations in the surface of the molten bath are reduced. As a result, fewer drops detach from the surface of the molten bath and soiling of the upper receptacle and the exhaust manifold is significantly reduced.

A top-blowing lance includes a refining oxygen gas blowing nozzle having a plurality of ejection openings through which oxygen gas is blown into an iron bath in a reaction vessel, the ejection openings being disposed along a circular orbit at intervals, and a burner nozzle having an axis coaxial with the central axis of the circular orbit, forming a flame inside the refining oxygen gas blowing nozzle, and having ejection openings for blowing a powder heated by the flame into the iron bath, wherein an indicator A that indicates the positional relationship between the ejection openings of the refining oxygen gas blowing nozzle and the ejection openings of the burner nozzle satisfies the specified conditions.