Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates

Abstract

The effects of ferrous and ferric iron as well as redox potential on copper and iron extraction from the copper flotation concentrate of Sarcheshmeh, Kerman, Iran, were evaluated using shake flask leaching examinations. Experiments were carried out in the presence and absence of a mixed culture of moderately thermophile microorganisms at 50˚C. Chemical leaching experiments were performed in the absence and presence of 0.15 M iron (ferric added medium, ferrous added medium and a mixture medium regulated at 420 mV, Pt. vs. Ag/AgCl). In addition, bioleaching experiments were carried out in the presence and absence of 0.1 M iron (ferric and ferrous added mediua) at pulp density 10% (w/v), inoculated bacteria 20% (v/v), initial pH 1.6, nutrient medium Norris and yeast extract addition 0.02% (w/w). Abiotic leaching tests showed that the addition of iron at low solution redox potentials significantly increased the rate and extent of copper dissolution but when ferric iron was added, despite a higher initial rate of copper dissolution, leaching process stopped. Addition of both ferrous and ferric iron to the bioleaching medium levelled off the copper extraction and had an inhibitory effect which decreased the final redox potential. The monitoring of ferrous iron, ferric iron and copper extraction in leach solutions gave helpful results to understand the behaviour of iron cations during chemical and bacterial leaching processes.

An electrochemical sensing approach for scouting microbial chemolithotrophic metabolisms

“…These compounds may be also present in our experiments when 0K medium is employed, therefore explaining the low ORP values obtained in these conditions. Additionally, other studies documented similar ORP values in absence of ferrous [40].…”

Bio-Heap Leaching of Primary Copper Sulfide Ore by JOGMEC

“…It is considered that iron-oxidizing bacteria had not worked due to the iron concentration having been over 10 g/L The ORP had increased gradually until around day 120, following which, the ORP had decreased slightly. It is known that the leaching kinetic of copper from chalcopyrite becomes low when the ORP is extremely high, and the suitable ORP for copper leaching is around 450 mV [4]. In this experiment, there was correlation between the ORP and the copper leaching kinetic coefficient "K" as shown in Fig.…”

Análise metagenômica da microbiota de solos de ambientes de mina de cobre

“…De modo similar, as reações ocorrerão também para os minérios de cobre como a calcopirita, covelita, bornita e calcocita (GRAY, 1997). A habilidade dessas bactérias é uma alternativa que vem sendo empregada na indústria mineral em processamento chamado biohidrometalurgia (AHMADI, 2012;ANJUM;SHAHID;AKCIL, 2012;JOHNSON, 2012;NORRIS et al, 2012;PANDA et al, 2012;WANG et al, 2012). Após a formação da drenagem ácida e se houver a presença de minerais possuidores de carbonato como a dolomita (CaMg(CO3)2) e calcita (CaCO3), a neutralização poderá ocorrer naturalmente, gerando então a drenagem neutra de mina.…”