3002
Depression of Sphalerite in Flotation of Complex Sulfide Ores by
Extracting Anglesite as a Pretreatment of Flotation
Kosei Aikawa
National Institute of Advanced Industrial Science and Technology (AIST)
Shunki Tanaka, Park Ilhwan, Naoki Hiroyoshi, Mayumi Ito
Hokkaido University
Sanghee Jeon
Akita University
ABSTRACT: In mineral processing of complex sulfide ores containing chalcopyrite, galena, and sphalerite,
flotation has been commonly used. Some types of the ores contain anglesite and the sphalerite floatability
increases due to activation of sphalerite by lead ions dissolved from anglesite. This makes the separation of
sphalerite from chalcopyrite difficult. In this study, extraction of anglesite to decrease the recovery of sphalerite
in flotation was investigated as a pretreatment of flotation. Finally, effects of a pretreatment extracting anglesite
on the sphalerite floatability was investigated to improve the separation of sphalerite from chalcopyrite.
INTRODUCTION
Complex sulfide ores, some of the most important sources
of critical metals, are typically composed of several metal
sulfide minerals such as chalcopyrite (CuFeS2), galena
(PbS), and sphalerite (ZnS). In the mineral processing of
complex sulfide ores consisting of Cu-Pb-Zn sulfide min-
erals, flotation has been commonly adopted to produce
concentrates of each mineral (Bilal 2022 Hornn 2021).
Some complex sulfide ores contain not only PbS but also
anglesite (PbSO4), the presence of which is problematic
for the separation of Cu, Pb, and Zn by flotation due to
the unwanted activation of ZnS by Pb2+ released from
PbSO4 (Aikawa 2021 Zeng 2021). In the general flotation
circuit of Cu-Pb-Zn sulfide ores, Cu and Pb sulfides are
first recovered to the froth, and then ZnS is recovered with
the assistance of activators such as CuSO4 (Wills 2016
Woodcock 2007). When PbSO4 is contained in complex
sulfide ores, however, Pb2+ is readily released from PbSO4
during conditioning and/or flotation due to its higher solu-
bility compared to PbS—the solubility products (Ksp) of
PbSO4 and PbS are 10−7.79 and 10−26.77, respectively (Ball
1991)—and activates the surface of ZnS via the formation
of PbS-like compounds, as illustrated in following equation
(Laskowski 1997 Rashchi 2002)
ZnS Pb PbS Zn
sh
2+ 2+ +=+
^^sh
The activation of ZnS by Pb2+ is known to increase the
ZnS floatability because of a higher affinity of PbS-like
compounds for xanthate compared to ZnS (Aikawa 2020
Houot 1992 Trahar 1997). As a result, ZnS is recovered
in the froth together with CuFeS2 and PbS, making their
Depression of Sphalerite in Flotation of Complex Sulfide Ores by
Extracting Anglesite as a Pretreatment of Flotation
Kosei Aikawa
National Institute of Advanced Industrial Science and Technology (AIST)
Shunki Tanaka, Park Ilhwan, Naoki Hiroyoshi, Mayumi Ito
Hokkaido University
Sanghee Jeon
Akita University
ABSTRACT: In mineral processing of complex sulfide ores containing chalcopyrite, galena, and sphalerite,
flotation has been commonly used. Some types of the ores contain anglesite and the sphalerite floatability
increases due to activation of sphalerite by lead ions dissolved from anglesite. This makes the separation of
sphalerite from chalcopyrite difficult. In this study, extraction of anglesite to decrease the recovery of sphalerite
in flotation was investigated as a pretreatment of flotation. Finally, effects of a pretreatment extracting anglesite
on the sphalerite floatability was investigated to improve the separation of sphalerite from chalcopyrite.
INTRODUCTION
Complex sulfide ores, some of the most important sources
of critical metals, are typically composed of several metal
sulfide minerals such as chalcopyrite (CuFeS2), galena
(PbS), and sphalerite (ZnS). In the mineral processing of
complex sulfide ores consisting of Cu-Pb-Zn sulfide min-
erals, flotation has been commonly adopted to produce
concentrates of each mineral (Bilal 2022 Hornn 2021).
Some complex sulfide ores contain not only PbS but also
anglesite (PbSO4), the presence of which is problematic
for the separation of Cu, Pb, and Zn by flotation due to
the unwanted activation of ZnS by Pb2+ released from
PbSO4 (Aikawa 2021 Zeng 2021). In the general flotation
circuit of Cu-Pb-Zn sulfide ores, Cu and Pb sulfides are
first recovered to the froth, and then ZnS is recovered with
the assistance of activators such as CuSO4 (Wills 2016
Woodcock 2007). When PbSO4 is contained in complex
sulfide ores, however, Pb2+ is readily released from PbSO4
during conditioning and/or flotation due to its higher solu-
bility compared to PbS—the solubility products (Ksp) of
PbSO4 and PbS are 10−7.79 and 10−26.77, respectively (Ball
1991)—and activates the surface of ZnS via the formation
of PbS-like compounds, as illustrated in following equation
(Laskowski 1997 Rashchi 2002)
ZnS Pb PbS Zn
sh
2+ 2+ +=+
^^sh
The activation of ZnS by Pb2+ is known to increase the
ZnS floatability because of a higher affinity of PbS-like
compounds for xanthate compared to ZnS (Aikawa 2020
Houot 1992 Trahar 1997). As a result, ZnS is recovered
in the froth together with CuFeS2 and PbS, making their