Bioleaching of enargite dominant copper sulfide under mesophilic and thermophilic conditions: Copper and arsenic extractions
Stirred Tank Reactor ( STR) and column leaching tests for copper extraction utilizing microorganisms were carried out using composited copper sulfide materials from Newmont Mining Corporations Yanacocha operation in Peru. Most of the composites contained high enargite as copper sulfide minerals with various ranges of covellite and very small amount of chalcocite. The copper grade of the ores ranges from 0. 27％ to 0. 83％ with 3. 3％ -15％ pyrite. Enargite and primary covellite were found to be very refractory under mesophilic conditions and all copper minerals were successfully leached under thermophilic conditions. Bioleaching was conducted with consortia of mesophilic iron-oxidizing bacteria containing species of Acidithiobacillus and Leptospirillum for bioleaching at ambient laboratory temperature (20 - 221 ) and with a mix of a thermophilic archaea culture containing Acidianus, Metallospheara and Sulfolobus species at 651. Copper extraction up to 98％ was obtained in enargite rich ore composite with relatively lower arsenic extraction of 6. 6％ — 78. 2％ under thermophilic conditions. Both copper and arsenic extractions under mesophilic conditions were very low indicating enargite was the only arsenic containing mineral in the ore. Lower arsenic extraction percentages indicates arsenic was released when enargite was leached under thermophilic conditions and precipitated back to a solid form which was stable in acidic bioleaching environment. Scanning Electron Microscopy (SEM) , XRD (X-ray Diffraction) and Raman Spectroscopy confirmed that scorodite (FeAsO4 ? 2H2O) was formed in the bioleach residues which is beneficial for water treatment and downstream copper processing. TOF - SIMS ( Time-ofFlight Secondary Ion Mass Spectrometry) also confirmed the scorodite formation. More tests were carried out using flotation concentrates containing 17. 1％ - 18. 6％ copper and 5. 5％ -2. 1％ arsenic. The flotation concentrates were bioleached in STRs under thermophilic conditions at 65t and the leached residue samples were collected during the bioleaching for SEM and Raman spectroscopy work to investigate the arsenic-iron co-precipitation under these conditions.
copper sulfide bioleaching enargite arsenic scorodite
Jaeheon Lee Sevket Acar James A. Brierley
Newmont Metallurgical Services 10101 E. Dry Creek Rd. , Englewood, CO 80112, United States Brierley Consultancy LLC PO Box 630012, Highlands Ranch, CO 80126, United States
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
565-573
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）