ISSN:
1662-8985
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The catalytic influence of Sulfolobus metallicus in the bioleaching of pure chalcopyrite at70° C and pH 1.5 was studied in shake flask experiments. In order to evaluate separately theinfluence of planktonic and attached cells on the catalytic process, in some experiments themicroorganisms were prevented from reaching chalcopyrite surface by keeping them in a chamberseparated by a 0.1 Millipore membrane. Leaching, which was conducted with a -80 # + 120#chalcopyrite sample, was characterized from monitoring Eh, pH, copper, ferrous and ferric ionconcentration in solution. In addition, the concentration of different sulphur species dissolved insolution either in aerated-abiotic and aerobic - biotic conditions, was determined with HPLC.Maximum copper dissolution was reached in experiments where all the microorganisms couldreach chalcopyrite. In experiments where microorganisms were maintained separated from thesulphide, the population of microorganisms still increased. However, in this case copper dissolutionwas only 50 % of the maximum reached when contact of microorganisms with chalcopyrite wasallowed, similar to that obtained in aerobic-abiotic conditions. On the other hand, in aerobic-abioticconditions there was formation of bisulfite (HSO3)-, bisulfate (HSO4)- and sulfate (SO4)2-, while inleaching experiments where microorganisms could reach chalcopyrite the formation of thiosulfate(S2O3)2- and sulfite (SO3)2- was additionally observed. It can be concluded that bioleaching ofchalcopyrite in the presence of Sulfolobus metallicus is the result of the cooperative action ofattached cells which catalize copper dissolution through formation of thiosulfate, sulfite andbisulfite, and planktonic cells which further oxidize these intermediate compound to bi-sulfate andsulfate
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/39/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.20-21.354.pdf
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