Pre-treatment of a Refractory Gold Sulfide Ore by Means of Acidithiobacilli Cells

 Cyanidation is a relatively simple and cheap technology to treat gold-containing ores. However, this process is not completely effective in refractory gold-bearing sulfide ores. In the case of very low-grade ores, biooxidation is an attractive alternative pre-treatment to render the gold amenable to extraction. This process utilizes the ability of acidophilic bacteria to oxidize the sulfide matrix, physically freeing the gold. The aim of this work is to evaluate the recovery of other available metals (Fe, Mn, Cu and Zn) during the biooxidation pre-treatment of an ore from Andacollo with low gold recovery (less than 50 %). This pretreatment was carried out in shaken flasks using pure cultures of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans and a mixed culture with both bacteria. Keywords Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, metal recovery, biooxidation.