In most cases, the slag used in hot metal dephosphorization is saturated with dicalcium silicate, and the partition ratio of phosphorus between dicalcium silicate and liquid slag is high. These results indicate the important role of solid dicalcium silicate in dephosphorization. In order to understand reaction kinetics and obtain an optimum treatment method, it is very important to know the influence of the solid phases in the slag. In this study, a new reaction model for hot metal dephosphorization is applied to the experimental results; this model considers the effects of dicalcium silicate and the dissolution rate of lime. By the calculation results, the influence of various factors on the reaction efficiency is discussed.
The calculated results are in almost good agreement with the experimental results obtained by various slag compositions and by various methods of flux and oxide additions to hot metal. By the calculation, in order to perform the dephosphorization reaction efficiently, we clarify the existence of the optimum basicity that considers the precipitation behavior of the solid phase in slag. Also, the optimum condition between the stirring energy and the supplying rate of flux and oxide was found.
