转炉钢渣RO相形成的抑制、铁的还原及提高胶凝活性的基础研究

With regard to the resource utilization of steel slag, the investigations and applications are mainly focus on the improvement of cementitious activity, and using high-temperature online modification technique to modify the composition of steel slag is proposed in recent years. However, the high content of Fe2O3 and FeO, and particularly the existence of RO phase can both reduce the cementitious activity of steel slag and influence the activation effect of online modification; further, iron content in the steel slag is wasted. In this project, a novel method will be proposed: the adjusting materials with reduction agents will be added during slag-off process in order to suppress RO phase, reduce Fe content and form similar water-granulated slag. This method can achieve a high-added value resource utilization of steel slag by recuperating Fe and increasing the cementitious activity. The project will start from the reaction thermodynamics and kinetics of molten steel slag in cooling process and the specific investigation contents include: the formation process of RO phase in steel slag, variation characteristics about the content and composition of RO phase in modified steel slag will be studied to reveal the mechanism of suppressing RO phase; the variation about the content and existing state of Fe element in modified steel slag will be studied to illustrate the relationship among the kinetics of reduction reaction, reduction degree of Fe2O3 and FeO and the suppression of RO phase; the composition, structure and melt characteristics of the modified steel slag will be studied to explain the reaction conditions of the thermodynamics and kinetics for decreasing melt viscidity and the formation of similar water-granulated slag; finally, the design of the adjusting materials for raw steel slag with different composition will be investigated. This project will establish the theoretical foundation for the steel slag online modification technique.

关于钢渣的资源化利用，大量研究与实践集中于胶凝活性的提高，申请者在参与钢渣在线重构技术的研究中发现，钢渣中Fe2O3、FeO含量偏高，尤其RO相的存在，不仅使钢渣胶凝活性低，而且影响了在线重构效果，更重要的是铁被浪费了。本项目提出在排渣过程中加入含还原组分的调节材料，抑制RO相形成，还原铁，并形成类似水淬矿渣，同时解决钢渣中铁的回收和提高胶凝活性，实现更高附加值的资源化利用。拟从熔态钢渣降温过程反应热力学和动力学研究入手，研究钢渣RO相形成过程及重构钢渣中RO相含量与组成变化规律，得出抑制RO相形成的机理；研究重构钢渣中铁元素含量及赋存状态变化规律，揭示铁还原反应动力学、还原程度及其与抑制RO相形成的关系；研究重构钢渣的组成、结构与熔体性质，阐明降低熔体粘度、获得类似水淬矿渣的反应热力学和动力学条件；并探讨适用于不同原钢渣的调节材料的设计与优化，为钢渣在线重构技术奠定理论基础。

关于钢渣的资源化利用，大量研究与实践集中于胶凝活性的提高，申请者发现，钢渣中Fe2O3、FeO含量偏高，尤其RO相的存在，不仅使钢渣胶凝活性低，更重要的是其中的铁被浪费了。本项目提出在熔态钢渣中加入含还原组分的调节材料，抑制RO相形成，还原铁，并形成类似水淬矿渣，同时解决钢渣中铁的回收和提高胶凝活性。项目从钢渣形成过程的反应热力学和动力学研究入手，研究了钢渣RO相形成过程及重构钢渣中RO相含量与组成变化规律，得出了通过重构抑制RO相形成的机理；研究了重构钢渣中铁元素含量及赋存状态变化规律，揭示了铁还原反应动力学、还原程度及其与抑制RO相形成的关系；研究了重构钢渣的组成、结构与熔体性质，阐明了降低熔体粘度、获得类似水淬矿渣的反应热力学和动力学条件；研究了适用于不同原钢渣的调节材料的设计与优化及重构工艺参数，得出钢渣碱度为1.0-3.0，初始FeOx含量15~30%时，在还原剂充足且用量一定，熔态钢渣在实验室重构温度为1500℃-1550℃，时间为30-60min条件下，FeOx还原率可达90%，得到的类似水淬矿渣的28d活性指数可达75%以上。本项目研究不仅提出了同时解决钢渣中铁的回收和提高渣的胶凝活性的钢渣还原重构新技术，实现了“渣、铁、热”的三效利用；而且完善了该项技术的理论基础，对实现钢渣高附加值的、更有效的大规模综合利用具有重要意义。