Effect of CaO/SiO2 on phase composition and content of steel slag
HAO Ning1,2, TIAN Zhi-hong1, JIA Ya-nan1, KONG Xiang-tao1, LI Hai-bo1
1. Strip Technology Department, Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China; 2. Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production Technology, Beijing 100043,China
Abstract：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.
2021, Vol. 31 
