Chalcopyrite concentrate leaching with biologically produced ferric sulphate.

Biological ferric iron production was combined with ferric sulphate leaching of chalcopyrite concentrate and the effects of pH, Fe3+, temperature and solids concentration on the leaching were studied. The copper leaching rates were similar at pH of 1.0-1.8 and in the presence of 7-90 g L-1 Fe3+ despite massive iron precipitation with 90 g L-1 Fe3+. Increase of the leaching temperature from 50 degrees C to 86 degrees C and solids concentration from 1% to 10% increased the copper leaching rate. Increase in solids concentration from 1% to 10% decreased the copper yields from 80% to 40%. Stepwise addition of ferric iron did not improve the copper yields. CuFeS2, Ag and Cu1.96S potentials indicated the formation of a passivating layer, which consisted of jarosite and sulphur precipitates and which was responsible for the decreased leaching rates.

[1]  N. Smalley,et al.  Operation of the Las Cruces ferric sulphate leach pilot plant , 2000 .

[2]  K. Natarajan.  Bioleaching of sulphides under applied potentials , 1992 .

[3]  E. Peters.  The Electrochemistry of Sulphide Minerals , 1977 .

[4]  D. Rawlings,et al.  Biomineralization of metal-containing ores and concentrates. , 2003, Trends in biotechnology.

[5]  S. Chander,et al.  Electrochemical characterization of the chalcopyrite/solution interface , 1992 .

[6]  J. Puhakka,et al.  High‐rate ferric sulfate generation by a Leptospirillum ferriphilum‐dominated biofilm and the role of jarosite in biomass retainment in a fluidized‐bed reactor , 2004, Biotechnology and bioengineering.

[7]  M. Ruonal,et al.  Different aspects of using electrochemical potential measurements in mineral processing , 1997 .

[8]  C. L. Brierley,et al.  Present and future commercial applications of biohydrometallurgy , 2001 .

[9]  J. Puhakka,et al.  Chloride-promoted leaching of chalcopyrite concentrate by biologically-produced ferric sulfate , 2004 .

[10]  C. Webb,et al.  Biological oxidation of ferrous sulphate by Thiobacillus ferrooxidans: a review on the kinetic aspects , 1998 .

[11]  W. Sand,et al.  Bacterial Leaching of Metal Sulfides Proceeds by Two Indirect Mechanisms via Thiosulfate or via Polysulfides and Sulfur , 1999, Applied and Environmental Microbiology.

[12]  W. Sand,et al.  (Bio)chemistry of bacterial leaching - direct vs. indirect bioleaching , 2001 .

[13]  J. Petersen,et al.  The influence of applied potentials and temperature on the electrochemical response of chalcopyrite during bacterial leaching , 2002 .

[14]  Antonio Ballester,et al.  New information on the chalcopyrite bioleaching mechanism at low and high temperature , 2003 .

[15]  J. Puhakka,et al.  High-rate iron oxidation at below pH 1 and at elevated iron and copper concentrations by a Leptospirillum ferriphilum dominated biofilm , 2005 .

[16]  F. Carranza,et al.  Silver catalyzed IBES process: application to a Spanish copper-zinc sulphide concentrate , 1997 .

[17]  P. Franzmann,et al.  The role of iron-hydroxy precipitates in the passivation of chalcopyrite during bioleaching , 2000 .

[18]  R. Dick.  Sulphur Cycling on the Continents: Wetlands, Terrestrial Ecosystems, and Associated Water Bodies. 1992 , 1993 .

[19]  J. Bockris,et al.  Trends in Electrochemistry , 1977 .

[20]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[21]  F. J. Alguacil,et al.  Comparative study on the selective chalcopyrite bioleaching of a molybdenite concentrate with mesophilic and thermophilic bacteria. , 2001, FEMS microbiology letters.

[22]  J. Banfield,et al.  Kinetics and mechanism of polythionate oxidation to sulfate at low pH by O2 and Fe3 , 2003 .

[23]  M. Nicol,et al.  The mechanism of the dissolution and passivation of chalcopyrite: An electrochemical study , 2003 .

[24]  D. Rawlings,et al.  Heavy metal mining using microbes. , 2002, Annual review of microbiology.

[25]  C. Klauber,et al.  Sulphur speciation of leached chalcopyrite surfaces as determined by X-ray photoelectron spectroscopy , 2001 .

[26]  O. Tuovinen,et al.  Oxidation of chalcopyrite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in shake flasks , 2002 .