Prediction Model for SiO[sub.2] Activity in the CaO-Al[sub.2]O[sub.3]-SiO[sub.2]-MgO Quaternary Slag System

• Published in: Minerals (Basel) 2023-04, Vol.13 (4)
• Main Authors: Lin, Yue, Yi, Yuanrong, Fang, Minghang, Ma, Wenqing, Liu, Wei
• Format: Article
• Language: English
• Subjects: Lime; Raw materials
• ISSN: 2075-163X; 2075-163X
• DOI: 10.3390/min13040509

Activity models based on the ion and molecule coexistence theory have been widely used in the refining of metallurgical slags, with the SiO[sub.2] content of slag playing a crucial role in improving the mechanical properties of refining slag-based cementitious materials. In order to improve the reactivity of SiO[sub.2] in slag, this study established a SiO[sub.2] activity prediction model for the CaO-Al[sub.2]O[sub.3]-SiO[sub.2]-MgO quaternary slag system based on the ion and molecule coexistence theory, validating the prediction results using reference values from the literature. Following this, the effects of w(SiO[sub.2]), w(CaO), w(CaO)/w(Al[sub.2]O[sub.3]), and R(w(CaO)/w(SiO[sub.2])) on SiO[sub.2] activity were explored (where w and R represent content and alkalinity, respectively). The results show that the model could accurately predict the SiO[sub.2] activity of refining slag at 1873k. When the SiO[sub.2] content was increased from 10% to 30%, with 60% w(CaO) and a w(MgO)/w(Al[sub.2]O[sub.3]) ratio of 0.25, the SiO[sub.2] activity exhibited a trend of initially increasing and then decreasing, with a maximum activity value of 0.1359 reached at 17.5% w(SiO[sub.2]). When slag contained 15% w(SiO[sub.2]) and a w(MgO)/w(Al[sub.2]O[sub.3]) ratio of 0.25, the SiO[sub.2] activity decreased with increasing CaO content, reaching a maximum activity value of 0.1268 when 55% w(CaO) was present. Therefore, by controlling the ratio of w(CaO)/w(Al[sub.2]O[sub.3]) and w(CaO)/w(SiO[sub.2]) in the slag to maintain a ratio of 3, the activity of SiO[sub.2] can be effectively increased.