Bioleaching of Metal Sulfides by Ferrimicrobium acidiphilum in the Presence of Chloride

摘要

Bioleaching of metal sulfides in a presence of chloride is still very problematic. Many well known bacterial strains have already been tested in bioleaching e.g. Acidithiobacillus thiooxidans or A. ferrooxidans but their resistance to chloride is low (less than 100 mM). Searching for new chloride resistant strains has two reasons: 1) The yield of the metals, especially copper from chalcopyrite, after leaching with small amount of NaCl (50-100mM) is higher. 2) There is a lack of fresh water resources in North Chile and it would be reasonable to use sea waters in bioleaching. Thus, the heterotrophic iron oxidizing bacterium Ferrimicrobium acidiphilum was cultivated with different concentration of NaCl (from 10mM to 1M). The medium used in this experiment was 1190 DSMZ (with addition of citric acid) supplemented with FeSO_4. Bacteria were cultivated for one week at 30°C and 130 rpm. Results shows that leaching is possible with more than 100 mM of NaCl.