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Highlights
•Ammoniacal leaching for dissolution of copper oxides.
•The pH in leaching should be controlled between pH 9–10.
•Ammonia leaching does not alter copper sulfides.
•PLS precipitates with S or SO2 to form CuS and/or Cu2S.
•Excess sulfur (150–200%) is more suitable for precipitation of Cu.
•Recoveries around 75% are achieved with the use of SF-323 and SF-114.
Abstract
Mixed copper ores are challenging to process, where the treatments are expensive, resulting in low recoveries, with products that are not commercially viable. The proposed research aims a sustainable method to recover copper from a mixture of oxides and sulfides minerals. The procedure involves three stages: (i) leaching with aqueous ammonia solutions at room temperature and varied pH, ammonia concentration, solid concentration, and particle size; (ii) PLS precipitation in copper sulfides by the addition of sulfur (or other copper sulfates) and SO2 (or additional sulfites or bisulfites); (iii) froth flotation to recover the value sulfide, considering a set of collectors and frothers. The outcomes obtained in this work were promising, achieving copper extraction of 70% in the leaching stage, precipitation of copper sulfides that surrounds 90%, and 75% of recovery by flotation.
（Quoted from Minerals Engineering Volume 149, 1 April 2020, 106242）
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