Column leaching of low-grade sulfide ore from Zijinshan copper mine

Copper and iron dissolution of Zijinshan low-grade copper sulfide ores was investigated in ore-packed columns. At 60 °C and pH 1.0, 37.1 g Fe(III) L−1 permitted effective copper dissolution and inhibited the activity of iron-oxidizing microorganisms. At 30 °C, microorganisms stimulated Fe(II) and pyrite oxidation, resulting in 85 and 54% of copper and pyrite extraction yields, respectively. Bacteria belonging to the genera Acidithiobacillus and Leptospirillumwere dominant as observed by real-time PCR assay. Aeration and inoculation of columnswere not necessary. Solutions had a higher pH of 1.7 in the columns operated without recirculation. Under these conditions, copper extraction was not affected and Fe(III) precipitated as jarosite, indicating a novel method for iron control in Zijinshan copper mine.