钢渣用作建筑材料时,由于其中含有大量游离氧化钙(f-CaO),稳定性较差,通常需要改性钢渣以提高其稳定性、胶凝性. 在对钢渣、高炉渣进行化学成分和矿物组成分析的基础上,对高炉渣改性钢渣的可能性进行了热力学计算,结果表明高炉渣中的SiO2与钢渣中f-CaO反应,生成胶凝相,同时降低了钢渣中的f-CaO含量. 本文通过研究热态高炉渣改性钢渣,结合X射线衍射、拉曼光谱、扫描电镜及能谱分析等研究方法,对改性钢渣的矿物成分、f-CaO含量、黏度变化等进行了分析. 研究发现随着热态高炉渣配比量的增加,改性渣黏度缓慢增加,改性钢渣中f-CaO、RO相含量降低,改性渣的胶凝性能提高. 在1550℃下,钢渣中添加10%高炉渣时,改性渣中2CaO·SiO2(C2S)、3CaO·SiO2(C3S)含量显著提高,f-CaO质量分数降至1.64%,稳定性大大提高,符合建材化使用要求. 此外,进一步使用焦炭还原改性渣中的铁,轻松实现了渣铁分离,提高改性渣的易磨性.
As the largest iron and steel producing country, China creates a large amount of steel and blast furnace slag each year. If these metallurgical slags are not properly handled, not only do they occupy land and damage the environment, but they also result in a waste of resources. Using steel slag as a building material usually leads to poor stability due to the high free lime (f-CaO) content. To improve its stability and gelation performance, steel slag usually needs to be modified. In this study, based on the chemical and mineral compositions of steel and blast furnace slags, a thermodynamic calculation of the modification process was performed. The results show that SiO2 in blast furnace slag reacts with f-CaO in steel slag to generate a gelatinous phase and f-CaO in the modified steelmaking slag decreases simultaneously. Here, the properties of steelmaking slags modified with hot blast furnace slag, including the mineral composition, f-CaO content, and viscosity, was studied using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy spectrum analysis. The results show that viscosity increases with increasing blast furnace slag content and the f-CaO and RO contents decrease. The gelation performance of the modified steelmaking slags is improved, especially in steelmaking slags modified with 10% blast furnace slag at 1550℃. When the content of 2CaO·SiO2 and 3CaO·SiO2 increase significantly and the f-CaO content decreases to 1.64%, the modified slags meet the requirements for building materials. Additionally, the study also attempted to use coke to reduce the iron in the modified slag. As a result, the facile separation of slag and iron is realized, and the grindability of the modified slag has been improved.