Mathematical model for powder injection refining of steel melt

The kinetics of refining by subsurface injection of slag forming material i nto the melt is studied by a mathematical model. Refining is considered to occur both by transitory and permanent contact reaction. An analytical solu tion of the differential equation is obtained which describes the dynamics of refining as a function of powder injection parameters such as powder rat e, residence time, partition coefficient, and bath stirring. The separate c ontributions of transitory and permanent reaction rates to the total rate a re calculated and discussed. Transitory efficiency is also calculated. Fina lly, the model solution is used to analyse the desulphurisation reaction. I t is found that the transitory efficiency is very low and, therefore, top s lag plays an important role in powder injection refining. IS/1336 (C) 1998 The Institute of Materials.