Z Boroumand; S Ghassa; M Moradian; H Abdollahi; Gh Fathabadi; K Fakhremoghadam
Abstract
In this research, the bioleaching process of mixture of sulfide and carbonate zinc and lead ore of Angouran Mine, whit local mixed mesophilic bacteria was studied. The purpose of this study was to indicate the effects of pulp density, Fe(II) concentration and initial pH in the zinc and lead bioleaching. ...
Read More
In this research, the bioleaching process of mixture of sulfide and carbonate zinc and lead ore of Angouran Mine, whit local mixed mesophilic bacteria was studied. The purpose of this study was to indicate the effects of pulp density, Fe(II) concentration and initial pH in the zinc and lead bioleaching. In Addition, the pH and Reduction-Oxidation Potential (ORP) have been monitored and evaluated during bioleaching process. The results showed that the zinc recovery through the bioleaching process (64.4 %) was much more than the leaching without bacteria (33.56 %). The results also showed, an increase in the pulp density caused a decrease in zinc recovery, and an increase in initial pH and ferrous concentration increased the zinc recovery. On the other hand, maximum lead recovery was 1.03 %. The study of bioleaching residual showed that the lead was recrystallized as Pb5(AsO4)3Cl. However, presenting the relation between mentioned parameters and Pb recovery was impossible due to lead precipitation. The results of this research could be used for bioleaching of high-grade Pb-Zn ores.
M.A Shabani; M Irannajad; A.R Azadmehr
Abstract
Copper oxide ores are usually leached in sulphuric acid solution. However, it has severe adverse impact on the environment. In this study, bioleaching and leaching by citric acid, as environmentally friendly methods, are investigated. The experiments were carried out on a copper oxide ore sample containing ...
Read More
Copper oxide ores are usually leached in sulphuric acid solution. However, it has severe adverse impact on the environment. In this study, bioleaching and leaching by citric acid, as environmentally friendly methods, are investigated. The experiments were carried out on a copper oxide ore sample containing copper content of 3.4%. This sample does not contain any energy source to grow the conventional bioleaching microorganisms (like Thiobacillusferrooxidans and Thiobacillusthiooxidans). This sample was leached by a heterotrophic bacterium, Pseudomonas aeruginosa. This bacterium produces organic acids in selected culture medium that operate as leaching agents. Leaching is investigated by citric acid, as an organic acid produced by this microorganism. The optimum bioleaching conditions were found as: glucose percentage of 6, bioleaching time 8 days and solid/liquid ratio of 1:80 and of optimum leaching conditions as: particle size range105-150µm, acid concentration of 0.2 M, 30 min dissolution time, solid/liquid ratio of 1:20 g/mL and temperature of 40°C. Under optimum bioleaching conditions 53 percent of copper was extracted and copper extraction under optimum leaching conditions was 92 percent.
