Thermodynamic Simulation of Iron and Nickel Recovery from Oxide Melts

Abstract

Significance of the research on the metal recovery from the oxide melts is primarily associated with pyrometallurgical treatment of ferrous and non-ferrous metal ores. The main task of the oxidized nickel ore treatment process is to increase the extraction of the valuable metals with the required (10–20%) nickel content in the ferronickel and the minimal amount of admixtures. According to thermodynamic simulation methods, we evaluate the indicators obtained at iron and nickel recovery from the oxide melt. We performed two series of calculations. In the first one, we varied the working body composition against the amount of iron and nickel oxides at the constant CFeO/CNiO ratio equal to 10. In the second one, at the constant CNiO content equal to 1.8%, we varied the CFeO value for the CFeO/CNiO ratios from 10 to 20. The dosed increase of the CO amount in the working body made it possible to trace the compositions changes in the oxide (CMеO) and the metal (CMе) melts, as well as the degrees of nickel (φNi) and iron (φFe) transition to the metal state. We present the CNiO, φNi = f(C0, VCO) correlation dependencies in the form of the second order polynomials. The φNi and the φFe indicators are changed with the introduced reducing agent amount, but depend insufficiently on the initial condensed phase composition. Those are the element contents in the initial melt and the amount of the introduced reducing agent that affect the composition of the formed Fe–Ni alloy. High (65–90%) nickel content is the specific alloys feature. The φNi value of about 98% was achieved at the introduced CO amount of about 80 m3 per melt ton. In that case, the iron recovery degree is within 5%. At the CFeO/CNiO ratio equal to 10, the nickel content in the alloy is in fact independent of its oxide content in the initial ore melt and is close to 65%. A CFeO/CNiO ratio increase from 10 to 20 results in the CNi decrease from 68.5 to 52.9%, respectively. The data obtained are significant for substantiation of the technology of treatment the low-quality oxidized nickel ores aimed at release of the required ferronickel composition.