Study On Kinetics Of Dephosphorization In CaO-SiO₂-P₂O₅-FeO Slag System

Under normal circumstances, phosphorus in the iron and steel products is harmful.But the phosphorus content in the metal can not be any control in iron-smelting operationon, so that it should to try to remove the phosphorus in the steeling process. Therefore, dephos-phorization problem plays a important role in the steelmaking process. From pervious human studies, we know that the restriction factor of dephosphorization reaction in alkaline steelmaking slag of Lime Department is the diffusion of the slag side. So that, the research on the dephosphorization kinetics of slag side has the great significance. To better unders-tand the dephosphorization mechanism, and to explore the dephosphorization process of various factors on the dephosphorization process, this article studied the dephosphorization dynamics of CaO-SiO2-P2O5-FeO slag system on the basis of previous research, builded the dephosphorization kinetic equation of CaO-SiO2-P2O5-of FeO slag system, and got the following conclusions.1. There was a layer of CaO-FeO layer between the generated solid solution layer and unreacted CaO layer. As the reaction proceeded, solid solution layer is ever thickening, and CaO-FeO layer continuously thickened.2. The restriction factor of CaO-SiO2-P2O5-FeO slag system dephosphorization process is combined action of the external diffusion of phosphorus in the slag and the internal diffusion of phosphorus in the solid solution layer.3. By measureing the diffusion coefficient Dc of phosphorus in the solid solution layer and the mass transfer coefficient k of phosphorus in the slag boundary layer, We got the kinetic equations in the condition of temperature of1300℃, the (FeO) content25%, and the alkalinity of1.1,1.3and1.5respectively: Also, we got the kinetic equations in the condition of temperature of1300℃, the alkalinity of1.1and the (FeO) content of20%and30%, respectively:At last, we got the kinetic equations in the condition of the alkalinity of1.3, the (FeO) content of25%, and temperature of1400℃and1450℃, respectively:With the parameters of different conditions and the kinetic equations, we got the calculated values of the conversion rates in different conditions, and the results agree well with the erperimental results...