Ni–Fe–Co alloy – magnesia-iron-silicate slag equilibria and the behavior of minor elements Cu and P in nickel slag cleaning

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Journal Title

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Volume Title

A2 Katsausartikkeli tieteellisessä aikakauslehdessä

Date

2021-11-01

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Mcode

Degree programme

Language

en

Pages

12
719-730

Series

Journal of Materials Research and Technology, Volume 15

Abstract

The increasing demand for metals and the tightening environmental restrictions on industries have led to a situation where improvements of new and existing process technologies for higher metal recoveries from primary and secondary resources are needed. This, in turn, requires a better understanding of process chemistry. The present study provides important fundamental information on the equilibrium reduction path and the formation of metal alloy in an electric furnace under nickel slag cleaning conditions, as well as the chemical properties of Ni, Co, Cu and P at these conditions. High-temperature equilibration experiments were conducted on magnesia-iron-silicate slags at silica saturation at 1400 ˚C (1637.15 K) and in the oxygen partial pressure range of 10−11–10−7 atm (1.01325 × 10−6–10−2 Pa). The samples were analyzed by electron microprobe (EPMA) for major and minor elements and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) for trace element compositions. Initially the slag contained 2 wt% Ni and 1 wt% Cu, Co and P each, added as oxides, and at PO2 = 10−7 atm, these metals were only present in the slag with no metal alloy formed. At lower partial pressures, the alloy formed and its composition changed from 90wt-% Ni-rich to 50 wt-% Ni – 40 wt% Fe alloy as the PO2 decreased. Copper vaporized to a great extent at all conditions. The minor metals were shown to be present as NiO, PO2.5, CoO and CuO0.5 species in slag over the PO2 = 10−8–10−10 atm range.

Description

Funding Information: The study received financial support from the BATCircle (grant 4853/31/2018) by Business Finland. Lassi Klemettinen is grateful for the doctoral study grant provided by the Finnish Steel and Metal Producers' Fund and the funding provided by Aalto University School of Chemical Engineering. This study utilized the Academy of Finland's RawMatTERS Finland Infrastructure (RAMI) based at Aalto University, GTK and VTT in Espoo. Mia Tiljander at Geological Survey of Finland is greatly appreciated for conducting the EPMA analyses. Funding Information: The study received financial support from the BATCircle (grant 4853/31/2018 ) by Business Finland. Lassi Klemettinen is grateful for the doctoral study grant provided by the Finnish Steel and Metal Producers' Fund and the funding provided by Aalto University School of Chemical Engineering . This study utilized the Academy of Finland's RawMatTERS Finland Infrastructure (RAMI) based at Aalto University, GTK and VTT in Espoo. Mia Tiljander at Geological Survey of Finland is greatly appreciated for conducting the EPMA analyses. Publisher Copyright: © 2021 The Author(s)

Keywords

Battery metals, LA-ICP-MS, Nickel processing, Reduction, Thermodynamic modelling

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Citation

Avarmaa, K, Taskinen, P, Klemettinen, L, O'Brien, H & Lindberg, D 2021, ' Ni–Fe–Co alloy – magnesia-iron-silicate slag equilibria and the behavior of minor elements Cu and P in nickel slag cleaning ', Journal of Materials Research and Technology, vol. 15, pp. 719-730 . https://doi.org/10.1016/j.jmrt.2021.07.112