Effect of FeO content on melting characteristics and structure of nickel slag

Abstract

A great deal of nickel slag containing a lot of Fe in the form of FeO is produced in the process of nickel smelting. The effect of FeO content on the melting characteristics and structure of nickel slag is studied via thermodynamic calculation and experiments, with the nickel slag of water quenching furnace as raw material, which is simplified to CaO-SiO2-FeO-MgO slag system. The results are shown as follows: with the increasing of FeO content, the precipitated primary phase changes from melilite to olivine. The liquidus temperature, softening temperature, hemispheric temperature, flow temperature, viscosity and critical viscosity temperature of slag system tends to decrease gradually, but the solid phase temperature tends to decrease first and then increase. The centre of [SiO4]4- tetrahedron symmetric stretching vibration band in the slag system moves to the low wave number region. The mole fraction of O0 in the slag decreases continuously, the mole fraction of O- and O2- increases. The complex silicon-oxygen tetrahedron structure gradually disintegrates and the structural unit tends to be simple.

Critical Review of the Metallurgical Operation of the Greek Nickel Industry and Perspectives, based on the recent Industrial Experience on Smelting Reduction Process

“…In any case, the conclusion that can be clearly drawn is that increase of the FeO content of the E/F slag, which is intimately related with the Fe content of the Laterite Mixture, as well as increase of the slag basicity, also intimately related with the decrease of SiO2 (%) content, results in considerable decrease of intensive slag foaming phenomena [10,11] and a series of operational problems. This can be clearly seen in Figure 12, where the evolution of ratio of energy consumed/energy loss due to operational problems caused by the poor quality of the laterite feed (Ni grade, Fe -SiO2), is presented.…”

Contribution to the Optimization of the Smelting Reduction of Nickeliferous Laterites, Based on the Recent Industrial Experience

“…An increase in the FeO content of the slag as well as a decrease in the slag viscosity result in a considerable decrease in intensive slag foaming phenomena [7,8] and a series of operational problems. This can also be clearly seen in Figure 6b, where the evolution of the ratio energy consumed/energy loss due to operational problems caused by the poor quality of the laterite feed (Ni grade, Fe-SiO 2 %) is presented.…”