MECHANISM OF SPHALERITE DEPRESSION IN AN OPEN CU/ZN FLOTATION
SEPARATION CIRCUIT
L. Xiaa, B. Harta, M. Furlotteb
a
Surface Science Western, Research Park, University of Western Ontario,
999 Collip Circle, LL31, London, Ontario, N6G 0J3, Canada
b
Mine Matagami, UNE Compagnie Glencore,
500, boul. Industriel, Matagami QC, J0Y 2A0, Canada
(*Corresponding author:
)
ABSTRACT
Plant and laboratory test work, developing the flowsheet for an open copper/zinc flotation separation
circuit was performed at Xstrata-Mine Matagami concentror, Canada. It was found that there was
significant difference between the laboratory and the plant tests, primarily for the sphalerite recovery in the
copper concentrate. The same ore was feed to both test work. There was no activation of sphalerite in the
plant but a significant activation happened during laboratory grinding. The plant had Cu grades above 15%
while the laboratory products were only 8-12%. A comparative surface chemical analysis was performed
with samples from both the plant flotation circuits and the bench-scale laboratory flotation cell in order to
provide a relative surface variability between the samples and identify surface species responsible for the
discrepancy in Zn recovery. Two significant observations were revealed. First, there is considerably more
copper on the sphalerite surface and collector for the lab float feed sample than the mill sample. Secondly,
there is considerably more iron oxyhydroxide on the mill samples, which is hydrophilic, can coat
completely or partially sphalerite surfaces, reducing collector/mineral interactions and hence floatability.
Despite numerous studies on the effect of galvanic coupling during grinding, there is little documented
evidence of the effect of milling environment on the flotation for plant operations. This observation
suggests that interaction between sulphide minerals and grinding media have a significant influence on the
subsequent stage of flotation.
KEYWORDS
Galvanic interaction, Grinding, Sphalerite, Surface chemistry, Copper/zinc separation