Extent of Ore Prereduction in Pilot-scale Production of High Carbon Ferromanganese

14 Pages Posted: 22 Sep 2021

See all articles by Tichaona Mukono

Tichaona Mukono

Norwegian University of Science and Technology (NTNU) - Department of Materials Science and Engineering

Jonas E Gjøvik

SINTEF Industry

Heiko Gærtner

SINTEF Industry

Maria Wallin

Norwegian University of Science and Technology (NTNU) - Department of Materials Science and Engineering

Eli Ringdalen

SINTEF Industry

Merete Tangstad

Norwegian University of Science and Technology (NTNU) - Department of Materials Science and Engineering

Date Written: September 12, 2021

Abstract

Three pilot-scale experiments have been conducted at SINTEF/NTNU in a 440 kVA AC electric furnace to demonstrate the process operation, energy requirements and CO2 emissions in the production of high carbon ferromanganese alloys. Comilog, UMK and Nchwaning (Assmang) ores blended with other materials, such as sinter and flux, thus achieving different charge mixtures have been utilized in the experiments. In the prereduction zone, higher manganese oxides in the ore are reduced to MnO through solid-gas exothermic reactions and at a temperature around 800oC, the unwanted endothermic Boudouard reaction is also active. As such, the total coke and energy consumption is highly dependent on if the prereduction occurs by CO gas or solid C. The pilot furnace has been excavated after each experiment and the extent of prereduction of the ore has been investigated by collecting samples from specific regions in the prereduction zone. In addition, material, and energy balance calculations for the three pilot experiments have been calculated using HSC Chemistry software. The HSC material and energy balance calculations have shown that the slag/alloy ratios, metal analyses, carbon consumption and the overall energy consumption are mainly affected by the composition of the charge mixtures. The relationship between the specific carbon consumption, the off-gas CO2/(CO2+CO) ratio and energy consumption to produce 1 tonne of HCFeMn alloy is discussed for the three different pilot-scale scenarios.

Keywords: Pilot-scale, prereduction, carbon consumption, energy, and material balance

Suggested Citation

Mukono, Tichaona and Gjøvik, Jonas E and Gærtner, Heiko and Wallin, Maria and Ringdalen, Eli and Tangstad, Merete, Extent of Ore Prereduction in Pilot-scale Production of High Carbon Ferromanganese (September 12, 2021). Proceedings of the 16th International Ferro-Alloys Congress (INFACON XVI) 2021, Available at SSRN: https://ssrn.com/abstract=3926275 or http://dx.doi.org/10.2139/ssrn.3926275

Tichaona Mukono (Contact Author)

Norwegian University of Science and Technology (NTNU) - Department of Materials Science and Engineering ( email )

Trondheim NO-7491
Norway

Jonas E Gjøvik

SINTEF Industry ( email )

Post box 4760 Torgarden
Trondheim, NO-7465
Norway

Heiko Gærtner

SINTEF Industry ( email )

Post box 4760 Torgarden
Trondheim, NO-7465
Norway

Maria Wallin

Norwegian University of Science and Technology (NTNU) - Department of Materials Science and Engineering

Trondheim NO-7491
Norway

Eli Ringdalen

SINTEF Industry ( email )

Post box 4760 Torgarden
Trondheim, NO-7465
Norway

Merete Tangstad

Norwegian University of Science and Technology (NTNU) - Department of Materials Science and Engineering ( email )

Trondheim NO-7491
Norway

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