Characterization of Double Leached Waelz Oxide for Identification of Fluoride Mineral

Suchandra Sar; Lena Sundqvist Öqvist; Tobias Sparrman; Fredrik Engström; Caisa Samuelsson

doi:10.3390/met9030361

Metals (Mar 2019)

Characterization of Double Leached Waelz Oxide for Identification of Fluoride Mineral

Suchandra Sar,
Lena Sundqvist Öqvist,
Tobias Sparrman,
Fredrik Engström,
Caisa Samuelsson

Affiliations

Suchandra Sar: Division Minerals and Metallurgical Engineering, Department of Civil, Environment and Natural Resources Engineering, Luleå University of Technology, 971 87 Luleå, Sweden
Lena Sundqvist Öqvist: Division Minerals and Metallurgical Engineering, Department of Civil, Environment and Natural Resources Engineering, Luleå University of Technology, 971 87 Luleå, Sweden
Tobias Sparrman: Department of Chemistry, Faculty of Science and Technology, Umeå University, 901 87 Umeå, Sweden
Fredrik Engström: Division Minerals and Metallurgical Engineering, Department of Civil, Environment and Natural Resources Engineering, Luleå University of Technology, 971 87 Luleå, Sweden
Caisa Samuelsson: Division Minerals and Metallurgical Engineering, Department of Civil, Environment and Natural Resources Engineering, Luleå University of Technology, 971 87 Luleå, Sweden

DOI: https://doi.org/10.3390/met9030361
Journal volume & issue: Vol. 9, no. 3
p. 361

Abstract

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Double leached Waelz oxide (DLWO), with 76% zinc, is a secondary zinc containing raw materials obtained by the treatment of electric arc furnace dust. The content of fluoride in DLWO is still too high for direct leaching, as fluoride has a detrimental effect on electrowinning for zinc production. Knowledge of the characteristics of DLWO, and especially on how a fluoride mineral might exist, can contribute to further improvement of the selective leaching for the removal of fluoride. In this study, DLWO was characterized using analytical techniques, such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), 19F liquid-state nuclear magnetic resonance (19F LS NMR), X-ray powder diffraction analysis (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and 19F solid-state nuclear magnetic resonance (19F SS NMR). This study showed that DLWO mainly consisted of zincite (ZnO), cerussite (PbCO3) and a spinel containing zinc, iron and manganese. The fluoride mineral identified was calcium fluoride (CaF2). In SEM analysis, fluorine was found in larger grains together with calcium and oxygen, which was possibly calcium carbonate.

Published in Metals

ISSN: 2075-4701 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Mining engineering. Metallurgy
Website: http://www.mdpi.com/journal/metals

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