转炉渣中含磷固溶体相的形成行为研究

Study on the formation behavior of phosphorus containing solid solution phase in BOF slag

本工作在1400℃下,将平均尺寸约450μm的硅酸二钙颗粒加入到CaO-FeO-SiO_(2)-P_(2)O_(5)体系转炉渣,研究了硅酸二钙的溶解及含磷固溶体相的形成行为。结果表明,硅酸二钙颗粒在FeO-SiO_(2)-P_(2)O_(5)体系转炉渣中溶解时,沿硅酸二钙颗粒周围形成3个区域:未熔硅酸二钙区域(边缘区域渗透高FeO含量的液态渣)、液相和固相(2CaO·SiO_(2)固相和2CaO·SiO_(2)-3CaO·P_(2)O_(5)固溶体)共存区域以及基体渣层;转炉渣中含磷固溶体相的形成方式为析出机制和扩散机制共存,通过析出机制形成的固溶体中的磷含量较高、其他元素含量较低;通过扩散机制形成的固溶体中的磷含量相对较低、其他元素含量相对较高。

Fully utilizing the solid in the slag is relatively helpful to improve the dephosphorization capacity of the slag.There are a large number of 2CaO·SiO_(2)solid phases in the actual steelmaking slag,and the steelmaking operation is usually carried out under the condition of dicalcium silicate saturation.However,the effect of the existing 2CaO·SiO_(2)in the slag on the formation of the solid solution has not been well clarified.In this work,the dissolution behavior of dicalcium silicate and the formation of phosphoruscontaining solid solution phase in CaO-FeO-SiO_(2)-P_(2)O_(5)system BOF (basic oxygen furnace) slag were studied by putting dicalcium silicate of the average size of about 450μm into the slag at 1400℃.The results showed that three regions were formed around the dicalcium silicate particles,namely the unmelted dicalcium silicate region,the coexistence region of the liquid phase and the solid phase (2CaO·SiO_(2)solid phase and 2CaO·SiO_(2)-3CaO·P_(2)O_(5)solid solution),and the substrate slag layer.The formation mode of the phosphorus-containing solid solution phase in converter slag was the coexistence of the precipitation mechanism and diffusion mechanism.The phosphorus content in the solid solution formed by the precipitation mechanism was high and the content of other elements was low.The phosphorus content in the solid solution formed by the diffusion mechanism was relatively low and the content of other elements was relatively high.The dissolution of dicalcium silicate particles and the formation of a solid solution showed that after the dicalcium silicate particles were added to the slag,Fe^(2+) and PO_(4)^(3-) in the slag diffused to the dicalcium silicate particles,and Ca^(2+) and SiO_(3)^(2-) in the dicalcium silicate diffused to the slag,forming a solid solution of 2CaO·SiO_(2)-3CaO·P_(2)O_(5);After that,dicalcium silicate particles were further dissolved and completely transformed into 2CaO·SiO_(2)-3CaO·P_(2)O_(5)solid solution.With the extension of time,the solid solution particles gradually grew up.