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Integration of Cu extraction and Zn electrowinning processes for energy storage

Elsevier

The main objective of this study is to integrate two energy-intensive metallurgical processes, Cu extraction from CuFeS₂ and Zn electrowinning, into a battery-like device that could incentivize renewable energy use at remote mining locations. In this device, Cu extraction and Zn electrowinning occur simultaneously during the charge cycle. During discharge, the device, referred to as a trifunctional battery (TFB), can supply back to an electrical circuit a portion of the stored energy. The re-dissolution of Zn during discharge and reversible reactions at a chalcopyrite slurry electrode are responsible for this energy release. The high initial specific energy (388 Wh– g –¹ at 0.5 C discharge rate) registered by this setup decreased to ≈50 Wh–g –¹ during the initial 15 galvanostatic charge ̸discharge cycles and remained almost constant in the subsequent 85 cycles. The low coulombic (≈50%) and energy efficiencies (≈40%) demonstrated by the TFB occurred at maximum (23%) Cu extraction from CuFeS₂. A feature of the TFB is that the normally unwanted irreversible reactions that occur in traditional batteries are in fact desirable in the TFB, i.e., they lead to valuable Cu extraction in addition to energy storage.

Article; Postprint

eng

Vancouver : University of British Columbia Library

10.14288/1.0396903

Applied Science, Faculty of; Materials Engineering, Department of

Reviewed

http://creativecommons.org/licenses/by-nc-nd/4.0/