Sülfürlü Bir Altın Cevherinin Karışık Asidofilik Kültürler ile Biyooksidasyonu

Özet

Biooxidation process is based on the activity of acidophilic chemolithoautotrophic microorganisms which are able to use ferrous iron and/or
sulphur as their energy source. This study investigated the biooxidation of a sulphide gold ore using mixed acidophilic mesophilic (Acidithiobacillus
ferrooxidans+Acidithiobacillus thiooxidans+Leptospirillum ferrooxidans), moderately thermophilic (Sulfobacillus acidophilus+Sulfobacillus
thermosulfidooxidans) and extremely thermophilic (Acidianus brierleyi+Sulfolobus metallicus) cultures and the effects of the biooxidation
conditions on the activities of the microorganisms during the biooxidation. In the tests, dissolution of arsenic and iron, degree of oxidation of
sulphide moiety and growth of bacteria/archaea were monitored. At high pulp densities, mesophilic mixed bacteria were observed to display better
oxidation performance than moderate and extreme thermophiles. The mixed extreme thermophile performed better than mesophiles and moderate
thermophiles only at low pulp densities (5% w/v). However, their growth and oxidation performance were adversely affected by increasing pulp
density. The oxidation performances of bacterial/archaeal cultures accorded with their growth yields. In the biooxidation tests performed in the
Erlenmeyer flasks at 20% w/v pulp density, medium iron dissolution/oxidation rates were 8.20-11.13 mg/L.hr. As bacterial growth rates were
0.0101–0.0119 hr-1 at all pulp densities, the number of bacteria in the solution was changing between 7.85x108-1.66x109bacteria/ml at the end of the
experiments. While sulphide oxidation obtained was between 77.11-87.35% at 5% (w/v) pulp density at the end of the biooxidation tests, sulphide
oxidation was between the interval of 37.95-55.22% at 20% w/v.