XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1599
both ores. Galena contains low proportions of Fe, Zn, Cd
and Bi in the ores.
The liberation of sphalerite and galena is presented in
Figure 3. Liberated grains are those in which the sphalerite
or galena contributes 90% of the particle area. Greater
than 1000 sphalerite and galena particles were analysed per
sample. Sphalerite liberation in the high-Mn ore is higher
(82%) compared to the low-Mn ore (73%). Due to the
higher sphalerite grade and better sphalerite liberation in the
high-Mn ore, higher Zn flotation recoveries are expected in
the high-Mn ore (this sample also had the coarsest sphaler-
ite in unbroken samples, Figure 2a). Unliberated sphalerite
in both ores is mostly associated with mica and sulphates.
In the low-Mn ore, which contained a major proportion
of galena, more than half (61.6%) of the galena is liber-
ated (this sample also had the coarsest galena in unbroken
samples, Figure 2b). Unliberated galena is mostly associated
with sphalerite and sulphates within this sample. Galena
liberation in the low-Mn ore, however, is considerably
lower—likely a consequence of the lower Pb grades.
Flotation Performance
The elemental recovery versus time for the two ores is illus-
trated in Figure 4. A ‘flat’ recovery indicates that these spe-
cies are depressed at that stage of the sequential float. As
expected, C (graphite) is predominantly recovered to the
C concentrate (45.3% in low-Mn and 18.7% in high-
Mn), Pb is predominantly recovered to the Pb concentrate
(54.6% in low-Mn and 48.9% in high-Mn), whereas Zn is
predominantly recovered to the Zn concentrate (41.1% in
the low-Mn Zn concentrate and 39.3% in the high-Mn Zn
concentrate). Small amounts of Fe are also recovered to all
of the concentrates.
For the low-Mn ore, the sequential recovery of Ag fol-
lows a similar trend to that of Pb, where the recovery dif-
ferences in the Pb concentrate are ~5%, as illustrated in
Figure 4. The majority of Ag is recovered to the low-Mn Pb
concentrate (58.3%), whereas 11.9% of Ag is recovered to
the low-Mn Zn concentrate. This equates to a grade of 87
g/t of Ag present within the low-Mn Pb concentrate. There
is no similarity in the sequential recovery trends between
Table 2. Assay data for the ores. All values are given in wt.% other than the Ag grade, in g/t
Sample Zn Fe Mn Pb S Si Ca Al Ag (g/t)
High-Mn 15.5 19.1 2.7 0.1 18.7 14.1 1.1 2.1 1.41
Low-Mn 6.3 22.5 0.5 1.2 26.9 13.8 0.3 2.6 5.12
High-MnLow-Mn
0
10
20
30
40
50
60
70
80
90
100
Others
Sulphates
Phosphates
Fe-Mn-Tioxides
Zn oxides
Garnet
Fe-Mg-Mn silicates
Mica
Quartz
Other sulf
Pyrite
Pyrrhotite
Sphalerite
Liberated Ga
Associations
Liberated
galena
of
unliberated
galena
High-MnLow-Mn
0
10
20
30
40
50
60
70
80
90
100
Others
Sulphates
Phosphates
Fe-Mn-Ti oxides
Zn oxides
Garnet
Fe-Mg-Mn silicates
Mica
Quartz
Other sulf
Galena
Pyrite
Pyrrhotite
Liberated Sp
Associations
Liberated
sphalerite
of
unliberated
sphalerite
A B
Figure 3. Sphalerite (a) and galena (b) liberation and association in the high-Mn and low-Mn samples. The association of
unliberated minerals of interest is also given
Galena
liberation
and
association
%
Sphalerite
liberation
and
association
%
both ores. Galena contains low proportions of Fe, Zn, Cd
and Bi in the ores.
The liberation of sphalerite and galena is presented in
Figure 3. Liberated grains are those in which the sphalerite
or galena contributes 90% of the particle area. Greater
than 1000 sphalerite and galena particles were analysed per
sample. Sphalerite liberation in the high-Mn ore is higher
(82%) compared to the low-Mn ore (73%). Due to the
higher sphalerite grade and better sphalerite liberation in the
high-Mn ore, higher Zn flotation recoveries are expected in
the high-Mn ore (this sample also had the coarsest sphaler-
ite in unbroken samples, Figure 2a). Unliberated sphalerite
in both ores is mostly associated with mica and sulphates.
In the low-Mn ore, which contained a major proportion
of galena, more than half (61.6%) of the galena is liber-
ated (this sample also had the coarsest galena in unbroken
samples, Figure 2b). Unliberated galena is mostly associated
with sphalerite and sulphates within this sample. Galena
liberation in the low-Mn ore, however, is considerably
lower—likely a consequence of the lower Pb grades.
Flotation Performance
The elemental recovery versus time for the two ores is illus-
trated in Figure 4. A ‘flat’ recovery indicates that these spe-
cies are depressed at that stage of the sequential float. As
expected, C (graphite) is predominantly recovered to the
C concentrate (45.3% in low-Mn and 18.7% in high-
Mn), Pb is predominantly recovered to the Pb concentrate
(54.6% in low-Mn and 48.9% in high-Mn), whereas Zn is
predominantly recovered to the Zn concentrate (41.1% in
the low-Mn Zn concentrate and 39.3% in the high-Mn Zn
concentrate). Small amounts of Fe are also recovered to all
of the concentrates.
For the low-Mn ore, the sequential recovery of Ag fol-
lows a similar trend to that of Pb, where the recovery dif-
ferences in the Pb concentrate are ~5%, as illustrated in
Figure 4. The majority of Ag is recovered to the low-Mn Pb
concentrate (58.3%), whereas 11.9% of Ag is recovered to
the low-Mn Zn concentrate. This equates to a grade of 87
g/t of Ag present within the low-Mn Pb concentrate. There
is no similarity in the sequential recovery trends between
Table 2. Assay data for the ores. All values are given in wt.% other than the Ag grade, in g/t
Sample Zn Fe Mn Pb S Si Ca Al Ag (g/t)
High-Mn 15.5 19.1 2.7 0.1 18.7 14.1 1.1 2.1 1.41
Low-Mn 6.3 22.5 0.5 1.2 26.9 13.8 0.3 2.6 5.12
High-MnLow-Mn
0
10
20
30
40
50
60
70
80
90
100
Others
Sulphates
Phosphates
Fe-Mn-Tioxides
Zn oxides
Garnet
Fe-Mg-Mn silicates
Mica
Quartz
Other sulf
Pyrite
Pyrrhotite
Sphalerite
Liberated Ga
Associations
Liberated
galena
of
unliberated
galena
High-MnLow-Mn
0
10
20
30
40
50
60
70
80
90
100
Others
Sulphates
Phosphates
Fe-Mn-Ti oxides
Zn oxides
Garnet
Fe-Mg-Mn silicates
Mica
Quartz
Other sulf
Galena
Pyrite
Pyrrhotite
Liberated Sp
Associations
Liberated
sphalerite
of
unliberated
sphalerite
A B
Figure 3. Sphalerite (a) and galena (b) liberation and association in the high-Mn and low-Mn samples. The association of
unliberated minerals of interest is also given
Galena
liberation
and
association
%
Sphalerite
liberation
and
association
%