Escudero-Castejon, L, Sanchez Segado, S orcid.org/0000-0002-3511-0723, Parirenyatwa, S et al. (2 more authors) (2017) A Cr⁶⁺⁻ Free Extraction of Chromium Oxide from Chromite Ores Using Carbothermic Reduction in the Presence of Alkali. In: Applications of Process Engineering Principles in Materials Processing, Energy and Environmental Technologies, The Minerals, Metals & Materials Series. TMS 2017 146th Annual Meeting & Exhibition, 26 Feb - 02 Mar 2017, San Diego, CA, USA. Springer International , pp. 179-188. ISBN 978-3-319-51090-3
Abstract
Oxidative alkali roasting of chromite is the state-of-the-art process for manufacturing chromium-containing chemicals, which involves dealing with serious environmental problems arising from handling Cr6+-containing wastes generated in this process. In this article a new method for the extraction of Cr2O3 from chromite ores is explained, based on the carbothermic reduction of concentrates in the presence of alkali investigated in the temperature range of 950–1050 °C. Under these conditions, the iron oxides present in the ore body are reduced to metallic iron and the resulting separation of chromium occurs by forming sodium chromite (NaCrO2). The reduced samples are magnetically separated for the recovery of an iron-rich fraction, and a non-magnetic fraction containing NaCrO2, MgO and other impurities. The further treatment of the non-magnetic fraction by leaching yields a Cr2O3-rich product of approximately 85% purity, with remaining alumina, alkali and magnesia. The main advantage of the process is that, under reducing atmosphere and subsequent leaching conditions, the oxidation of Cr3+ to Cr6+ is completely avoided; thereby decreasing the risk of land, air and water pollution.
Metadata
Item Type: | Proceedings Paper |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Minerals, Metals & Materials Society 2017. This is an author produced version of a paper published in Applications of Process Engineering Principles in Materials Processing, Energy and Environmental Technologies. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Chromite ore; Carbothermic reduction; Alkali; Chromium(VI); Chromium extraction; Chromium oxide |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Funding Information: | Funder Grant number NERC NE/L002280/1 EU - European Union 331385 EPSRC GR/T08074/01 Millennium Inorganic Chemicals Ltd NO REF GIVEN London & Scandinavian Metallurgical Co Ltd 9416064 |
Depositing User: | Symplectic Publications |
Date Deposited: | 22 Feb 2017 11:09 |
Last Modified: | 02 Mar 2020 13:02 |
Published Version: | https://doi.org/10.1007/978-3-319-51091-0_16 |
Status: | Published |
Publisher: | Springer International |
Identification Number: | 10.1007/978-3-319-51091-0_16 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:112637 |