Study on Diffusion Rate of Phosphor in CaO Solid Phase Particles in Dephosphorization Slag

There is some amount of solid particle of CaO in dephosphorizing slag of molten steel.In order to investigate the diffusion rate of phosphor in CaO particle,CaO particle suspending with wire of Mo were put into molten slag of CaO-SiO₂-Fe_tO-P₂O₅ at the temperature between 1 385℃ and 1 450℃,and then were taken out to cool down in the air after 10 s,20 s,30 s,60 s and 100 s of thermal insulation respectively.The distribution of phosphor in the experimental heterogeneous dephosphorizing slag between CaO particle and slag was measured by SEM-EDS and the diffusion coefficient was calculated in order to study the effect of temperature on diffusion velocity of phosphor in CaO solid particle.The result shows that at experimental temperature,phosphor can enter into CaO solid particle by diffusing,however,the further diffusing of phosphor is difficult to realize because of the reaction of CaO particle with other material in slag.The DP,diffusion velocity coefficient of phosphor in CaO solid particle,is 9.536×10^-10m2/s at 1 400℃ and they are 5.757 49×10^-10m²/s and 7.42×10^-9m²/s respectively at 1 385℃ and 1 450℃.Between 1 380℃ and 1 450℃,the activation energy of diffusing in CaO particle of phosphor in slag of CaO-SiO₂-Fe_tO-P₂O₅ is 9.638×10⁵ J/mol.