SiO₂改质对转炉钢渣中C₂S相优势析出及钢渣自粉化的影响

Influence on C₂S Dominant Precipitation and Self-Pulverization of Converter Steel Slag by SiO₂ Modification

摘要: 转炉钢渣微粉化是目前实现钢渣综合利用的有效途径之一，但是转炉钢渣易磨性差，严重制约了其微粉化。而利用转炉钢渣中硅酸二钙相(2CaO•SiO₂，简称C₂S)在降温过程中发生β-C₂S向γ-C₂S晶型转变引起体积膨胀产生的内应力，可实现钢渣的自粉化。因此钢渣中C₂S相含量高低将影响钢渣的自粉化效果。本论文以CaO (50 wt%)-MgO (10 wt%)-SiO₂ (10 wt%)-Fe₂O₃ (30 wt%)四元合成渣系作为基础转炉渣系，研究了SiO₂改质对转炉钢渣中C₂S优势析出的影响。实验结果表明：通过SiO₂改质合成转炉钢渣，将二元化学碱度控制在2左右时，可实现渣中C₂S相优势析出，有利于钢渣自粉化，渣粉150 μm过筛率最高可达94.3%。本实验结果为转炉钢渣资源的进一步回收利用提供了参考。

Abstract: Converter steel slag pulverization is one of effective ways for its massive utilization. However, the poor grindability caused by complex chemical composition and microstructure of converter steel slag makes it very difficult to be pulverized. Converter steel slag contains polymorph dicalcium silicate (C₂S), and its crystal structure can transform from β-C₂S to γ-C₂S under cooling condition accompanied by volume expansion, which could result in self-pulverization and improve steel slag grindability. According to chemical composition of practical steel slags, CaO (50 wt%)-MgO (10 wt%)-SiO₂ (10 wt%)-Fe₂O₃ (30 wt%) slag has been chosen as basic experimental synthetic slag and modified with different SiO₂ addition amounts. The results show that with the synthetic slag basicity of 2, C₂S can precipitate dominantly in converter steel slag, which results in high self-pulverization effect, and screening rate of slag powder below 150 μm can even reach 94.3%. The results of the experiments provide scientific reference for further recycling of converter steel slag.