Calculation Model for Activity of FeO in Quaternary Slag System SiO 2 -CaO-Al 2 O 3 -FeO

摘要

According to the coexistence theory of slag structure, a calculation model for the activity of FeO in the quaternary system SiO 2 -CaO-Al 2 O 3 -FeO of depleted copper slag was established. The model was used to calculate and analyze the effects of temperature (T), basicity (B), and Al 2 O 3 content on the activity of FeO ( N FeO ). The results show that temperature has little impact on N FeO . With increased basicity, N FeO first increased slightly, then increased sharply, and finally decreased. It is easier for CaO to combine with SiO 2 than FeO to form calcium silicate, which replaces FeO in 2FeO·SiO 2 and increases N FeO . However, when basicity is higher than 2.0, CaO not only reacts with SiO 2 , but also combines with FeO to form calcium ferrate compounds to decrease N FeO . In addition, the activity of FeO decreases with increased Al 2 O 3 content because of the reaction between CaO and Al 2 O 3 . The results can be used as a theoretical basis to guide the carbothermal reduction process of copper slag.