Biooxidation of refractory gold bearing ores by moderately thermophilic chemolithotrophic bacteria and their association
The main characteristics of a periodic bioleaching of the refractory gold-bearing pyrite ore from the Tandzut deposit ( Armenia) by moderate thermophilic Sulfobacillus thermosulfidooxidans subsp. asporogenes and original thermotolerant strains Leptospirillum spp. isolated from above mentioned ores were studied. Moderate thermophilic bacteria of the genus Sulfobacillus are considered to be the most perspective bacteria for tank bioleaching of refractory gold containing ores and concentrates. However, these bacteria are mixotrophic and for their growth they require organic sources of carbon. It has been shown that the amount of iron leached by mixotrophically growth sulfobacilli is about 5 times more than that of by authortophic growing bacteria during biooxidation of Tandzut refractory ores. However the investigations indicate that on 7 or 10th day of cultivation of sulfobacilli their growth becomes slower and as a result the rate of oxidation of gold bearing ores reduces. It has been established that the cause of reducing of growth rate and oxidation activity of sulfobacilli is the exhausting of required organic carbon compounds. One of the ways of maintaining high activity of sulfobacill during oxidation of refractory ores can be their cultivation together with iron oxidizing bacteria Leptospirillum spp. Cultivation of S. thermosulfidooxidans subsp. asporogenes together with Leptospirillum spp. increased the degree of pyrite ore leaching up to 98. 4％ instead of 34. 1 ％ in the case of the former bacterium alone. It is worth mentioning that the mutually beneficial relation occurs among them and as a result the sulfobacilli can grow without additional organic compounds. It has been established that the most efficient way in terms of high rate of bioleaching of iron from refractory gold bearing ores is to carry out the process in two stages; in the first stage to realize bioleaching at 501 with mixotrophic growing sulfobacilli then at 37T) using the association of sulfobacilli and leptospirilli.
moderate thermophiles sulfobacilli leptospirilli biooxidation gold-bearing pyrite ores
Narine Vardanyan Levon Markosyan Arevik Vardanyan
Center of Microbiology and Microbial Depository NAS of Armenia, 2201, Abovyan city, Armenia Center of Microbiology and Microbial Depository NAS ofArmenia, 2201, Abovyan city, Armenia
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
597-600
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）