Selective leaching of Cu and Co from stratiform sediment-hosted copper ore using deep eutectic solvents

Heathcote, Rupert, Nash, William, Graf, Arthur, Hudson-Edwards, Karen A. and Crane, Rich 2026. Selective leaching of Cu and Co from stratiform sediment-hosted copper ore using deep eutectic solvents. Minerals Engineering 237 , 109990. 10.1016/j.mineng.2025.109990

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Abstract

Hydrometallurgical processing of sediment-hosted stratiform Cu ores traditionally relies on strong, often toxic mineral acids, with a primary focus on Cu recovery. Cobalt, an important but frequently overlooked byproduct, is typically recovered with poor efficiency (e.g., ∼45 %). To address this knowledge gap, we investigated the simultaneous leaching of Cu and Co from a Cu ore from the Central African Copperbelt using oxalic, formic, and lactic acid-based choline chloride (ChCl) deep eutectic solvents (DESs). Results were compared with conventional leaching using sulfuric acid (10 g/L), both with and without ferrous sulfate (1.5 g/L). Across the temperature (20–80 °C) and time (1–90 h) ranges studied, all DES formulations achieved leaching efficiencies comparable to those of sulfuric acid. Choline chloride–lactic acid (ChCl:LA) exhibited the best overall performance, yielding higher selectivity for Cu and Co. This was most pronounced at 20 °C, where, after 90 h, 94 % and 85 % of Cu and Co were respectively leached, but only 5 % of the Fe was dissolved, compared to 96 %, 76 % and 9 % recorded for sulfuric acid. These findings highlight the potential of DESs, particularly those composed of hydrogen bond donors with chelating and reducing properties, such as ChCl:LA, as highly promising alternatives for Cu and Co leaching from stratiform sediment-hosted Cu ores.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Chemistry
Publisher:	Elsevier
ISSN:	0892-6875
Date of First Compliant Deposit:	7 January 2026
Date of Acceptance:	30 November 2025
Last Modified:	07 Jan 2026 14:00
URI:	https://orca.cardiff.ac.uk/id/eprint/183674

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