Viscosity and Structure of CaO–SiO2–“FeO”–Al2O3–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al2O3

Abstract

Nickel slag can be recycled as one of excellent secondary sources due to valuable amounts of iron contents. Viscosity of CaO–SiO2–“FeO”–Al2O3–MgO slag system during iron‐extracting process from nickel slag by aluminum dross is investigated from 1723 to 1873 K. Evolution of viscosity and structure are studied with “FeO”/Al2O3 ratio decreasing from 1.69 to 0.48. Under the coupling effect of “FeO” and Al2O3, the viscosity increases slowly before the reduction degree of 60% following by a significant increase. Structure investigation shows that Al2O3 is always acting as the network former, and the transition of dominant role from “FeO” to Al2O3 not only leads to the disappearance of structural unit Q0 in Raman spectra, but also the occurrence of more complex unit Q3, signifying an evident increase in the degree of polymerization (DOP) of the slag. Additionally, the viscosity evolution during the reduction process is calculated upon the non‐isothermal thermodynamic model.