摘要
The efficiency of the stationary lance for steelmaking desulphurization is concerned for its fixed injection point in the molten bath.The dynamic free lance,discovered accidentally in 2005,is a new type of injection lance with its top end connected with a flexible joint so that the lance tip could move during the injection.Without mechanical driving apparatus,the free lance is capable to inject the reagents into wider area of the bath,dispersion injection of the reagent may be expressed by C = B/S,where B is reagent injection rate,S is the injection area covered by the lance tip.The preliminary investigation of the free lance indicated that the lance movement caused forceful interaction of the injection gas with the liquid phase,and jet trajectory changed the route due to the drag force from the liquid phase.A refractory lance with length of 2 m has been converted into the free lance for further study,indicating that the heavy free lance used in the industry could achieve certain extent of movement for dispersion injection,and this prediction has been proved recently by industrial application of the 9 meters free lance used for the injection modification of the end-slag from steelmaking converter.