Electrolysis of metal oxides in MgCl2 based molten salts with an inert graphite anode

Yating Yuan; Wei Li; Hualin Chen; Zhiyong Wang; Xianbo Jin; George Z. Chen

doi:10.1039/c5fd00231a

Electrolysis of metal oxides in MgCl₂ based molten salts with an inert graphite anode

Yating Yuan, Wei Li, Hualin Chen, Zhiyong Wang, Xianbo Jin, George Z. Chen

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

Electrolysis of solid metal oxides has been demonstrated in MgCl₂-NaCl-KCl melt at 700 °C taking the electrolysis of Ta₂O₅ as an example. Both the cathodic and anodic processes have been investigated using cyclic voltammetry, and potentiostatic and constant voltage electrolysis, with the cathodic products analysed by XRD and SEM and the anodic products by GC. Fast electrolysis of Ta₂O₅ against a graphite anode has been realized at a cell voltage of 2 V, or a total overpotential of about 400 mV. The energy consumption was about 1 kW h kg_Ta^-1 with a nearly 100% Ta recovery. The cathodic product was nanometer Ta powder with sizes of about 50 nm. The main anodic product was Cl₂ gas, together with about 1 mol% O₂ gas and trace amounts of CO. The graphite anode was found to be an excellent inert anode. These results promise an environmentally-friendly and energy efficient method for metal extraction by electrolysis of metal oxides in MgCl₂ based molten salts.

Original language	English
Pages (from-to)	85-96
Number of pages	12
Journal	Faraday Discussions
Volume	190
DOIs	https://doi.org/10.1039/c5fd00231a
State	Published - 2016
Externally published	Yes

Funding

Funders	Funder number
Engineering and Physical Sciences Research Council	EP/J000582/1

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10.1039/c5fd00231a

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title = "Electrolysis of metal oxides in MgCl2 based molten salts with an inert graphite anode",

abstract = "Electrolysis of solid metal oxides has been demonstrated in MgCl2-NaCl-KCl melt at 700 °C taking the electrolysis of Ta2O5 as an example. Both the cathodic and anodic processes have been investigated using cyclic voltammetry, and potentiostatic and constant voltage electrolysis, with the cathodic products analysed by XRD and SEM and the anodic products by GC. Fast electrolysis of Ta2O5 against a graphite anode has been realized at a cell voltage of 2 V, or a total overpotential of about 400 mV. The energy consumption was about 1 kW h kgTa-1 with a nearly 100% Ta recovery. The cathodic product was nanometer Ta powder with sizes of about 50 nm. The main anodic product was Cl2 gas, together with about 1 mol% O2 gas and trace amounts of CO. The graphite anode was found to be an excellent inert anode. These results promise an environmentally-friendly and energy efficient method for metal extraction by electrolysis of metal oxides in MgCl2 based molten salts.",

author = "Yating Yuan and Wei Li and Hualin Chen and Zhiyong Wang and Xianbo Jin and Chen, {George Z.}",

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doi = "10.1039/c5fd00231a",

language = "English",

volume = "190",

pages = "85--96",

journal = "Faraday Discussions",

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T1 - Electrolysis of metal oxides in MgCl2 based molten salts with an inert graphite anode

AU - Yuan, Yating

AU - Li, Wei

AU - Chen, Hualin

AU - Wang, Zhiyong

AU - Jin, Xianbo

AU - Chen, George Z.

PY - 2016

Y1 - 2016

N2 - Electrolysis of solid metal oxides has been demonstrated in MgCl2-NaCl-KCl melt at 700 °C taking the electrolysis of Ta2O5 as an example. Both the cathodic and anodic processes have been investigated using cyclic voltammetry, and potentiostatic and constant voltage electrolysis, with the cathodic products analysed by XRD and SEM and the anodic products by GC. Fast electrolysis of Ta2O5 against a graphite anode has been realized at a cell voltage of 2 V, or a total overpotential of about 400 mV. The energy consumption was about 1 kW h kgTa-1 with a nearly 100% Ta recovery. The cathodic product was nanometer Ta powder with sizes of about 50 nm. The main anodic product was Cl2 gas, together with about 1 mol% O2 gas and trace amounts of CO. The graphite anode was found to be an excellent inert anode. These results promise an environmentally-friendly and energy efficient method for metal extraction by electrolysis of metal oxides in MgCl2 based molten salts.

AB - Electrolysis of solid metal oxides has been demonstrated in MgCl2-NaCl-KCl melt at 700 °C taking the electrolysis of Ta2O5 as an example. Both the cathodic and anodic processes have been investigated using cyclic voltammetry, and potentiostatic and constant voltage electrolysis, with the cathodic products analysed by XRD and SEM and the anodic products by GC. Fast electrolysis of Ta2O5 against a graphite anode has been realized at a cell voltage of 2 V, or a total overpotential of about 400 mV. The energy consumption was about 1 kW h kgTa-1 with a nearly 100% Ta recovery. The cathodic product was nanometer Ta powder with sizes of about 50 nm. The main anodic product was Cl2 gas, together with about 1 mol% O2 gas and trace amounts of CO. The graphite anode was found to be an excellent inert anode. These results promise an environmentally-friendly and energy efficient method for metal extraction by electrolysis of metal oxides in MgCl2 based molten salts.

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JO - Faraday Discussions

JF - Faraday Discussions

ER -

Electrolysis of metal oxides in MgCl₂ based molten salts with an inert graphite anode

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