Abstract: For the cyclic enrichment of P element in converter slag, it is proposed to use reducing agent to remove part of P element in molten slag in the stage of slag splashing. At present, the dephosphorization rate of slag gasification in industrial tests has reached a level of close to 40 %. In order to further improve the dephosphorization rate of slag, the change law of P element in different phases in the process of slag dephosphorization was studied, and then the theoretical guidance and optimization direction for dephosphorization process operation were provided. The mineralogical phase before and after the reduction of converter slag were analyzed by SEMEDS and XRD.  The results show that the P element of converter slag is mainly enriched in 2CaO·SiO₂ and 3CaO·SiO₂ phase displayed in granular and lath. The average distribution of P element in this micro region observed by electron microscope is 2.4 %. The gasification dephosphorization reaction is mainly carried out in these phosphorus rich phases, and the fracture of phosphorus rich phase becomes smaller after the reaction, the average mass fraction of P element in the micro area is 0.7 %. The content of P in CaO·Fe₂O₃ phase and RO phase of converter slag is low, and the average mass fraction is 1.1 % and 1.5 % respectively. After dephosphorization, the two phases are mixed, and the P mass fraction is reduced to 0.27 % on average.In order to further promote the dephosphorization reaction in phosphorus rich phase, dynamic conditions need to be improved.

Key words: converter slag, reduction, gasification dephosphorization, mineralogical phase