XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3031
(Table 5(c)) reported irregular-shaped or cube-like blocks
that they described as blocky at high magnification (≥
3,000 k) and a particle size of 10 µm. On the other hand,
the Indian talc (Table 5(c)) revealed a platy texture with
the stacking of multiple talc platelets. Also, SEM imaging
of talc samples by Holland &Murtagh (2000) revealed a
similar platy and blocky morphology.
Calculation of the Aspect Ratio from SEM data
The aspect ratio calculations were performed using Image J
software, which relies on talc particle projections acquired
from SEM micrographs. All 2D images were imported as
an image sequence in the form of a numerically sorted,
stacked image to be processed automatically. Before each
measurement, the scale was calibrated to ensure results that
were precise and consistent. Stack images were subsequently
converted to grayscale from their corresponding coloured
thresholds. The grayscale photos were transformed into
binary images and then masked in order to perform colour
segmentation. The objective of using colour segmentation
was to ensure precise quantification by distinguishing talc
from other minerals. The shape analysis involved measur-
ing approximately 1,313 talc particles. The shape of the talc
particle was analysed using ferret diameter as the primary
shape descriptor. The aspect ratio was determined by divid-
ing the maximum by the minimum Feret diameters. The
inverse of the aspect ratio was utilised in this study because
descriptors in the 0 – 1 category are more likely to pro-
duce mineral particle distributions that are fairly normal
(Little et al. 2015). Also, it is theoretically easier to define
the aspect ratio with possible values ranging from 0 to 1.
Table 4. XRD morphology index calculated from the 004 and 020 peak intensities
Talc Origin 004 Peak Intensity 020 Peak Intensity
Morphology
Index, %
India 12.5 ± 0.7 0.6 ± 0.2 95.0 ± 1.0
USA 10.9 ± 0.3 2.5 ± 0.3 77.0 ± 5.0
Table 5. Micrographs of talc of different micron sizes from different geological locations
(a) 400 µm (b) 200 µm (c) 10 µm
India
USA
(Table 5(c)) reported irregular-shaped or cube-like blocks
that they described as blocky at high magnification (≥
3,000 k) and a particle size of 10 µm. On the other hand,
the Indian talc (Table 5(c)) revealed a platy texture with
the stacking of multiple talc platelets. Also, SEM imaging
of talc samples by Holland &Murtagh (2000) revealed a
similar platy and blocky morphology.
Calculation of the Aspect Ratio from SEM data
The aspect ratio calculations were performed using Image J
software, which relies on talc particle projections acquired
from SEM micrographs. All 2D images were imported as
an image sequence in the form of a numerically sorted,
stacked image to be processed automatically. Before each
measurement, the scale was calibrated to ensure results that
were precise and consistent. Stack images were subsequently
converted to grayscale from their corresponding coloured
thresholds. The grayscale photos were transformed into
binary images and then masked in order to perform colour
segmentation. The objective of using colour segmentation
was to ensure precise quantification by distinguishing talc
from other minerals. The shape analysis involved measur-
ing approximately 1,313 talc particles. The shape of the talc
particle was analysed using ferret diameter as the primary
shape descriptor. The aspect ratio was determined by divid-
ing the maximum by the minimum Feret diameters. The
inverse of the aspect ratio was utilised in this study because
descriptors in the 0 – 1 category are more likely to pro-
duce mineral particle distributions that are fairly normal
(Little et al. 2015). Also, it is theoretically easier to define
the aspect ratio with possible values ranging from 0 to 1.
Table 4. XRD morphology index calculated from the 004 and 020 peak intensities
Talc Origin 004 Peak Intensity 020 Peak Intensity
Morphology
Index, %
India 12.5 ± 0.7 0.6 ± 0.2 95.0 ± 1.0
USA 10.9 ± 0.3 2.5 ± 0.3 77.0 ± 5.0
Table 5. Micrographs of talc of different micron sizes from different geological locations
(a) 400 µm (b) 200 µm (c) 10 µm
India
USA