2632 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Scheelite, often finely disseminated and occasionally lami-
nated, overlaid sedimentary structures. It formed anhedral
crystals measuring 5 to 300 µm, averaging 150 µm, con-
stituting the liberation mesh. Close mineral associations
were observed between scheelite and fluorite/vesuvianite,
featuring a significant proportion of intergrowth crystals
(Foucaud et al., 2019a). Furthermore, extensive albitisa-
tion of the skarn horizons impacted the entire paragenesis,
including scheelite, potentially resulting in substantial pro-
portions of intergrowth crystals.
Zeta Potential
The zeta potential measurements as a function of pH are
plotted in Figure 2. The zeta potential of fluorite is sig-
nificantly higher than that of scheelite, regardless of pH,
with a difference ranging from 15 to 40 mV (Figure 2).
Scheelite displays a negative zeta potential on almost the
whole pH range and its isoelectric point (IEP) seems at
pH values between 2 and 3. Besides, fluorite presents an
isoelectric point at a pH value of about 4 to 5, consider-
ing the standard deviation of acquisition, and a zeta poten-
tial that is positive below those values and negative above
those values. The values of IEP and zeta potential as a func-
tion of pH for scheelite are in very good agreement with
the values reported in the literature (Arnold and Warren,
1974 Atademir et al., 1979 Gao et al., 2016 Hicyilmaz
and Özbayoglu, 1992 K. I. Marinakis and Kelsall, 1987
Ozcan and Bulutcu, 1993). This behavior is attributed to
the fact that the molar concentration of WO42– is signifi-
cantly higher than that of Ca2+, resulting in an excess of
WO42– anions near the surface, i.e., in the inner plane
(Atademir et al., 1979 Hicyilmaz and Özbayoglu, 1992
Figure 1. Micrographs of thin sections of Main Skarn layer (a, b, c) and Lower Skarn layer (d) observed under cross-polarized
light (a, c, d) and polarized light (b) with optical microscopy. Sch =Scheelite F =Fluorite Ves =Vesuvianite Zo =Zoisite Gr
=Grossular Px =Pyroxene Cal =Calcite Qz =Quartz Fd =undetermined feldspars Kf =K-feldspars
Scheelite, often finely disseminated and occasionally lami-
nated, overlaid sedimentary structures. It formed anhedral
crystals measuring 5 to 300 µm, averaging 150 µm, con-
stituting the liberation mesh. Close mineral associations
were observed between scheelite and fluorite/vesuvianite,
featuring a significant proportion of intergrowth crystals
(Foucaud et al., 2019a). Furthermore, extensive albitisa-
tion of the skarn horizons impacted the entire paragenesis,
including scheelite, potentially resulting in substantial pro-
portions of intergrowth crystals.
Zeta Potential
The zeta potential measurements as a function of pH are
plotted in Figure 2. The zeta potential of fluorite is sig-
nificantly higher than that of scheelite, regardless of pH,
with a difference ranging from 15 to 40 mV (Figure 2).
Scheelite displays a negative zeta potential on almost the
whole pH range and its isoelectric point (IEP) seems at
pH values between 2 and 3. Besides, fluorite presents an
isoelectric point at a pH value of about 4 to 5, consider-
ing the standard deviation of acquisition, and a zeta poten-
tial that is positive below those values and negative above
those values. The values of IEP and zeta potential as a func-
tion of pH for scheelite are in very good agreement with
the values reported in the literature (Arnold and Warren,
1974 Atademir et al., 1979 Gao et al., 2016 Hicyilmaz
and Özbayoglu, 1992 K. I. Marinakis and Kelsall, 1987
Ozcan and Bulutcu, 1993). This behavior is attributed to
the fact that the molar concentration of WO42– is signifi-
cantly higher than that of Ca2+, resulting in an excess of
WO42– anions near the surface, i.e., in the inner plane
(Atademir et al., 1979 Hicyilmaz and Özbayoglu, 1992
Figure 1. Micrographs of thin sections of Main Skarn layer (a, b, c) and Lower Skarn layer (d) observed under cross-polarized
light (a, c, d) and polarized light (b) with optical microscopy. Sch =Scheelite F =Fluorite Ves =Vesuvianite Zo =Zoisite Gr
=Grossular Px =Pyroxene Cal =Calcite Qz =Quartz Fd =undetermined feldspars Kf =K-feldspars