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.

Viscosity of BOF Slag

“…Thereby, no change or no contamination or minor contamination was previously reported. It was found that the molybdenum from the crucible was dissolved in the slags during viscosity measurements of FeO-containing nickel slag (MoO3 concentrations of 0.25-0.52 wt% and 0.25-0.46 wt% for higher and lower FeO content, respectively) [21,22]. The viscosity curves in our experiments were repeated several times.…”

“…The influence of temperature, slag basicity, and Cr 2 O 3 content on the viscosity of stainless steelmaking slags has been experimentally determined by Liu et al [20]. The viscosity of FeO-containing nickel slag was investigated as a function of FeO/Al 2 O 3 ratio and of Al 2 O 3 /SiO 2 ratio by Zhang and co-workers [21,22]. The influence of TiO 2 content between 5 and 15 wt% on the viscosity of the BF slags was investigated by Jiao and co-workers, using the rotating viscometer.…”

“…Liu et al used scanning electron microscope with energy-dispersive X-ray spectroscopy SEM/EDS in order to evaluate the quantity of secondary phases, e.g., spinel particles, during the viscosity measurement of the stainless steelmaking slags [20]. The structure of FeO-containing nickel slag was analyzed by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy in [21,22]. The effect of TiO 2 and FeO [24], TiO 2 and Al 2 O 3 [25], and MgO and Al 2 O 3 [26,27] on the structure of BF slag was investigated using FTIR and Raman analysis.…”

“…Chemical analysis of the slag samples after the viscosity measurements was performed only in [17,28], and only Fe was analyzed in [21,22,24]. The non-linear relationship of the natural logarithm of viscosity with respect to inverse of the temperature from the data was reported in [23,33].…”

Recycling Nickel Slag by Aluminum Dross: Iron-extraction and Secondary Slag Stabilization

“…In our previous works, we have discussed the viscosity evolution of slags during the reduction process, and a better kinetic condition could be obtained. 31,32) The purpose of this paper is to investigate the feasibility of the innovative approach. As mentioned above, modifier (or flux) is of significance to the treatment process.…”