Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the mineral phase

Sanchez-Segado, Sergio and Monti, Tamara and Katrib, Juliano and Kingman, Samuel and Dodds, Chris and Jha, Animesh (2017) Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the mineral phase. Scientific Reports, 7 . p. 18016. ISSN 2045-2322

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Abstract

Current methodologies for the extraction of tantalum and niobium pose a serious threat to human beings and the environment due to the use of hydrofluoric acid (HF). Niobium and tantalum metal powders and pentoxides are widely used for energy efficient devices and components. However, the current processing methods for niobium and tantalum metals and oxides are energy inefficient. This dichotomy between materials use for energy applications and their inefficient processing is the main motivation for exploring a new methodology for the extraction of these two oxides, investigating the microwave absorption properties of the reaction products formed during the alkali roasting of niobium-tantalum bearing minerals with sodium bicarbonate. The experimental findings from dielectric measurement at elevated temperatures demonstrate an exponential increase in the values of the dielectric properties as a result of the formation of NaNbO3-NaTaO3solid solutions at temperatures above 700 °C. The investigation of the evolution of the dielectric properties during the roasting reaction is a key feature in underpinning the mechanism for designing a new microwave assisted high-temperature process for the selective separation of niobium and tantalum oxides from the remainder mineral crystalline lattice.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Engineering > Department of Chemical and Environmental Engineering
Identification Number: https://doi.org/10.1038/s41598-017-18272-3
Depositing User: Eprints, Support
Date Deposited: 10 Jan 2018 13:21
Last Modified: 12 Jun 2018 05:56
URI: http://eprints.nottingham.ac.uk/id/eprint/49023

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