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 acid mine drainage (AMD) generating sulfidic tailings have a total mass of1,639,130 t containing 1.65 g/t Au, 34.5 g/t Ag, 7.74 % Fe, 5.91 % S, 3.2 % As, 0.75 % Zn and 0.05% Cu. The precious metals Au and Ag are enriched in the fine fractions. Approximately 35 % of thematerial is below 25 /m in size and 53 % below 63 /m. Electron microprobe analysis of a sulfideconcentrate of the tailings, produced by gravity separation, proved the occurrence of pyrite andarsenopyrite with appreciable sphalerite and galena. Refractory gold (up to 316 g/t) is hosted in Asrichzones of some arsenopyrites. Approximately 200 g of the sulfide concentrate of the tailings wasbiooxidized in laboratory shake flasks using an adapted mixed culture of Acidithiobacillusferrooxidans (Ram 6F), Acidithiobacillus thiooxidans (Ram 8T) and Leptospirillum ferrooxidans(R3). During biooxidation, arsenopyrite was preferentially dissolved and the secondary mineraltooeleite (Fe8(AsO4)6(OH)5·H2O) precipitated. The following cyanidation of the biooxidized sulfideconcentrate showed a recovery of 97 % and 50 % for Au and Ag, respectively. The values were 56% and 18 % for the untreated concentrate. The recovery of Au and Ag from the tailingssignificantly reduces the costs for the tailings remediation to mitigate AMD release
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/39/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.20-21.91.pdf
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