Relationship between bioleaching performance, bacterial community structure and mineralogy in the bioleaching of a copper concentrate in stirred-tank reactors

Abstract

Hugues. Relationship between bioleaching performance, bacterial community structure and mineralogy in the bioleaching of a copper concentrate in stirred-tank reactors. Applied Microbiology and Biotechnology, Springer Verlag, 2011, 89 (2) The experiments undertaken to produce the techno-economic data were also an opportunity to carry out more fundamental research. The objective of this work was to combine the results of the bioleaching experiments, in terms of copper recovery, with the results of bacterial community monitoring and mineralogy residue analysis.Batch and continuous bioleaching tests were carried out with 10% solids, at 42 °C and with a pH between 1.2 and 1.6. Final copper recovery was higher in batch cultures than in continuous mode (>95% vs. 91%). Mineralogical analysis showed that the limiting factor for copper recovery was incomplete chalcopyrite dissolution in both cases. However, chalcopyrite was even less dissolved in continuous conditions. This was also related to a variation in bacterial community structure. The population in all tests was composed of Acidithiobacillus caldus, Leptospirillum ferriphilum and one or two species of Sulfobacillus (thermosulfidooxidans and sometimes benefaciens) but Sulfobacillus and more generally sulphur oxidizers were more represented in batch mode.It was proposed that, due to their capacity to reduce inorganic compounds, sulphur oxidizers may be efficient in limiting chalcopyrite surface hindering. It may help to better dissolve this mineral and reach a better copper recovery.

Enhancement of Biofilm Formation on Pyrite by Sulfobacillus thermosulfidooxidans

“…It is reported that the smaller proportion of Sulfobacillus in leaching consortia under continuous conditions was correlated with the reduction of chalcopyrite leaching kinetics than in batch mode. Spolaore et al [11] compared chalcopyrite leaching efficiency of an undefined leaching consortia under continuous condition with that in batch mode. The results show that the leaching kinetics in the continuous test were lower than in the batch test, which can be attributed to a smaller proportion of Sulfobacillus, in agreement with Foucher et al [12].…”

Effects of dissolved oxygen and carbon dioxide under oxygen-rich conditions on the biooxidation process of refractory gold concentrate and the microbial community

“…Many studies (Coram and Rawlings, 2002;Spolaore et al, 2011) showed that Leptospirillum spp. was a major microorganism in a commercial stirred tank reactor at 35-50°C; these results agree with this work.…”

Bio-processing of copper from combined smelter dust and flotation concentrate: A comparative study on the stirred tank and airlift reactors

“…Design is further complicated by the multiphase nature of the pulp, consisting of an aqueous solution with cells adhering to the mineral in suspension, and also a suspended solid and air bubbles [7,16].…”

“…As a result, parameters such as volumetric productivity and degree of extraction can be significantly increased [7][8][9][10]. Stirred tank reactors (STRs) are also favorable mass transfer devices providing a large gas-liquid interfacial area and high shear stress to enhance the mass transfer [11].…”