Influence of temperature on the fixation and penetration of silver during the chalcopyrite leaching using moderate thermophilic microorganisms

Bioleaching of chalcopyrite using mesophilic microorganisms considerably improves in the presence of silver. However, the studies carried out with moderate thermophilic microorganisms do not show a significant improvement with regard to the use of mesophilic bacteria. The main objective of the present work has been to study the silver fixation on chalcopyrite at 35 and 45degreesC and its influence on the microbiological attack. Different observations using SEM, EDS microanalysis and concentration profiles using electron microprobe have been carried out. The study of the different samples showed that silver fixation was more favourable at 35degreesC than at 45degreesC. In addition, bacterial action improved silver penetration through attack cracks.