Abstract: Aiming at the poor kinetic conditions of hot metal desulfurization with granular magnesium injection by a lance with single straight nozzle and the difficulties in the implementation of mechanical lance rotation, a lance with external spiral guiding groove was proposed, and the injection process was numerically simulated. It is found that the lance with spiral guiding groove can effectively improve the stirring of hot metal and reduce splashing compared with the conventional one. The industrial test and application of hot metal desulfurization with granular magnesium injection in a 250 t hot metal ladle in a steel plant show that, the hot metal splashing and magnesium vapor combustion on the slag surface are significantly reduced. The unit consumption of desulfurizer is reduced by 6.0 % on average and the average service life of injection lance reaches 180 heats, which show its excellent application effect. 

Key words: hot metal desulfurization, injection desulfurization, numerical simulation, structure of injection lance