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.
Kinnunen
P H-M
PH
Institute of Environmental Engineering and Biotechnology, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland. paivi.kinnunen@tut.fi
Heimala
S
S
Riekkola-Vanhanen
M-L
ML
Puhakka
J A
JA
D019149:Bioreactors; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper / Q000032:analysis / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry; D005290:Ferric Compounds / Q000378:metabolism* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism*; D010084:Oxidation-Reduction; D013696:Temperature
D005290:Ferric Compounds; C012819:chalcopyrite; C024823:ferric sulfate; D003300:Copper; D007501:Iron