CaO/SiO2对钢渣平衡物相的组成及含量的影响

为了提高钢渣的资源化利用率,找到合适的钢渣成分改质工艺,以CaO-SiO₂-MgO-FeO-Fe₂O₃-Al₂O₃六元渣系为研究对象,利用FactSage热力学软件计算并分析了不同w(CaO)/w(SiO₂)组成的模拟钢渣在1 600~200 ℃冷却过程中平衡物相组成和含量的变化规律。得出钢渣的平衡物相主要有Ca₂SiO₄相、Ca₂(Al,Fe)₂O₅相、MgO-FeO固溶体相、f-CaO相、少量的Ca₃MgAl₄O₁₀相以及w(CaO)/w(SiO₂)为2时钢渣中才会析出的Ca₃MgSi₂O₈相。w(CaO)/ w(SiO₂)越低,钢渣析出的有益相硅酸盐相含量越高,而铁酸盐相、MgO-FeO固溶体相和f-CaO相不利于钢渣循环利用的物相含量越低。因此,降低钢渣的w(CaO)/ w(SiO₂)可以改善钢渣在后续处理和使用过程中的易磨性以及安定性。

Effect of CaO/SiO2 on phase composition and content of steel slag

In order to improve the resource utilization rate of steel slag and find an appropriate composition modification process, the six-element slag system of CaO-SiO₂-MgO-FeO-Fe₂O₃-Al₂O₃ was studied. During the cooling process from 1 600 to 200 ℃, the equilibrium phase composition and content of the given steel slags with different w(CaO)/w(SiO₂) was calculated and analyzed by FactSage thermodynamic software. The conclusion showed that equilibrium phase mainly included Ca₂SiO₄ phase, Ca₂(Al,Fe)₂O₅ phase, MgO-FeO solid solution phase, f-CaO phase, Ca₃MgAl₄O₁₀ phase, and Ca₃MgSi₂O₈ phase precipitated out of steel slag when w(CaO)/w(SiO₂) was 2. The lower w(CaO)/w(SiO₂), the higher the content of beneficial silicate phase, and the lower the content of ferrite phase, MgO-FeO solid solution phase and f-CaO phase which were all not conducive to steel slag recycling. Therefore, reducing w(CaO)/w(SiO₂) of steel slag can improve the abrasion resistance and stability of steel slag in subsequent treatment and use.