Dw. Dew et al., Bioleaching of base metal sulphide concentrates: A comparison of mesophileand thermophile bacterial cultures, PROCESS MET, 9, 1999, pp. 229-238
Billiton Process Research has carried out extensive research over the past
four years to develop new process technology using bioleaching for extracti
on of copper and nickel from their sulphide concentrates. Continuous pilot
scale and laboratory batch testwork has been carried out with adapted mesop
hile bacterial cultures at 40 degrees C - 45 degrees C, moderate thermophil
e cultures at 50 degrees C - 55 degrees C and thermophile cultures at 65 de
grees C - 85 degrees C.
Pilot scale work has demonstrated the commercial viability of mesophile cul
tures for bioleaching of secondary copper sulphide and nickel sulphide conc
entrates. Moderate thermophiles offer benefits in terms of reduced cooling
requirements for commercial reactors and, in the case of bioleaching of nic
kel concentrates, some selectivity over bioleaching of pyrite. Continuous p
ilot scale testwork has shown that thermophiles achieve efficient bioleachi
ng of primary copper sulphide and nickel sulphide concentrates, giving much
higher recoveries than achieved by bioleaching with a mesophile or moderat
e thermophile culture.