XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3029
at the Clayton Research Laboratories of CSIRO Mineral
Resources, Clayton, Victoria, Australia.
Flotation Experiment
The talc was wet ground to a particle size of D80 75 +5
µm. The flotation tests were carried out in a 1.5 L flotation
cell containing 1,100 g of 0.01 NaCl Milli-Q water and 8
wt.% slurry with 15 g and 75 g of talc and quartz, respec-
tively. Talcs were kept in the pH range of 8 – 9 by using 1
M NaOH and/or 1 M HCl. Methyl isobutyl carbinol (25
ppm) was used as a frother at a dosage of 2.2 mL. The air
flow rate, conditioning time, and impeller speed were all
2 L/min, 3 min, and 840 rpm, respectively. The flotation
of all different talcs was performed under the same condi-
tions without the use of a collector. Four concentrates were
collected for each test. at 0.5, 2, 4, and 8 minutes by hand
scraping at a constant depth and rate. The tailing was fil-
tered. After being weighed while wet, all flotation products
were allowed to dry in an oven overnight. The dry weight
was used to calculate the grade and mass recovery.
X-Ray Diffraction Analysis
The talc powder was spread in a sample holder ring with
the use of a spatula if necessary. The sample holder was
closed, the assembly was carefully turned over, and the but-
ton was pressed to release the sample holder, ready for XRD
analysis.
X-ray diffraction data were collected using a Panalytical
MPD instrument fitted with a cobalt broad-focus X-ray
tube operated at 55 kV and 40 mA. Data were collected
over the range of 4–80° 2θ in Bragg-Brentano geometry
with an automatic divergence slit (for a fixed irradiation
length on the sample of 8.2 mm), a 10 mm beam mask,
a programmable anti-scatter slit, and a fast X’Celerator
Si strip operated in 1D mode. Patterns were collected in
steps of 0.017° 2θ with a counting time of 0.5 sec per step,
for an overall counting time of approximately 35 min.
Quantitative-phase analysis of the XRD data was per-
formed using Topas (V7).
SEM Analysis
The method consists of three steps: sample preparation,
image capture and collection, and image processing and
analysis. A dispersion was prepared by mixing 3.0 mg of par-
ticles with 1.0 mL of water and three drops of Triton X-100.
An ultrasonic process was then carried out to disperse the
minerals. A droplet from this suspension was placed on a
carbon stub and allowed to dry overnight. The dispersion
was air-dried and then imaged and collected using a SEM.
For scanning electron microscopy (SEM) analysis, the sam-
ple was carbon coated, placed on a standard SEM speci-
men holder, and inserted into the instrument, which was
a FEI Quanta 400 field emission environmental scanning
electron microscope (FEI, Eindhoven, The Netherlands).
Secondary and backscattered electron images were col-
lected at the same magnification. The acquired images
were imported into the image processing programmes
ilastik (Version 2) and ImageJ (v1.54f), where they were
calibrated, and a global scale bar was established for subse-
quent image analysis.
Statistical Analysis
Statistical treatment of the data was performed using
Statistical Package for Social Science” 13.0 (SPSS Inc.,
Chicago, IL, USA).
RESULTS AND DISCUSSION
Mineralogical Compositions of Talc
The diffractogram of the various talcs, as depicted in
Figure 1, depicts the peak assignments that correspond
to each mineral. Considering their distinct geological for-
mations and weathering processes, it was anticipated that
the talcs depicted in Figure 1 would exhibit variations in
mineralogy.
Talc, with the highest intensity peaks, was the principal
mineral in Indian talc, while United States talc, while con-
taining talc, also displayed peaks corresponding to clino-
chlore, goethite, serpentine, and magnesite. According to
Figure 1(a), US talc contains a lot of impurities and is thus
not as pure as Indian talc (Figure 1(b), which is the pur-
est form of the mineral). Table 3 displays the results of the
mineralogical quantification, which show that the Indian
talc contains approximately 100% talc, and that the US talc
contains 81% talc. This further indicates that the Indian
talc is of higher purity.
Calculation of the Aspect Ratio from XRD Data
The platy morphology of the talcs was determined using
the orientation of the surface or crystal plane obtained from
Table 2. Chemical compositions of different talcs
Talc SiO
4, %MgO, %Al
2 O
3, %Fe
2 O
3, %Loss on Fusion, %
India, I 62.1 30.0 0.04 2.0 5.4
United States, U 57.4 26.1 2.7 6.8 6.1
at the Clayton Research Laboratories of CSIRO Mineral
Resources, Clayton, Victoria, Australia.
Flotation Experiment
The talc was wet ground to a particle size of D80 75 +5
µm. The flotation tests were carried out in a 1.5 L flotation
cell containing 1,100 g of 0.01 NaCl Milli-Q water and 8
wt.% slurry with 15 g and 75 g of talc and quartz, respec-
tively. Talcs were kept in the pH range of 8 – 9 by using 1
M NaOH and/or 1 M HCl. Methyl isobutyl carbinol (25
ppm) was used as a frother at a dosage of 2.2 mL. The air
flow rate, conditioning time, and impeller speed were all
2 L/min, 3 min, and 840 rpm, respectively. The flotation
of all different talcs was performed under the same condi-
tions without the use of a collector. Four concentrates were
collected for each test. at 0.5, 2, 4, and 8 minutes by hand
scraping at a constant depth and rate. The tailing was fil-
tered. After being weighed while wet, all flotation products
were allowed to dry in an oven overnight. The dry weight
was used to calculate the grade and mass recovery.
X-Ray Diffraction Analysis
The talc powder was spread in a sample holder ring with
the use of a spatula if necessary. The sample holder was
closed, the assembly was carefully turned over, and the but-
ton was pressed to release the sample holder, ready for XRD
analysis.
X-ray diffraction data were collected using a Panalytical
MPD instrument fitted with a cobalt broad-focus X-ray
tube operated at 55 kV and 40 mA. Data were collected
over the range of 4–80° 2θ in Bragg-Brentano geometry
with an automatic divergence slit (for a fixed irradiation
length on the sample of 8.2 mm), a 10 mm beam mask,
a programmable anti-scatter slit, and a fast X’Celerator
Si strip operated in 1D mode. Patterns were collected in
steps of 0.017° 2θ with a counting time of 0.5 sec per step,
for an overall counting time of approximately 35 min.
Quantitative-phase analysis of the XRD data was per-
formed using Topas (V7).
SEM Analysis
The method consists of three steps: sample preparation,
image capture and collection, and image processing and
analysis. A dispersion was prepared by mixing 3.0 mg of par-
ticles with 1.0 mL of water and three drops of Triton X-100.
An ultrasonic process was then carried out to disperse the
minerals. A droplet from this suspension was placed on a
carbon stub and allowed to dry overnight. The dispersion
was air-dried and then imaged and collected using a SEM.
For scanning electron microscopy (SEM) analysis, the sam-
ple was carbon coated, placed on a standard SEM speci-
men holder, and inserted into the instrument, which was
a FEI Quanta 400 field emission environmental scanning
electron microscope (FEI, Eindhoven, The Netherlands).
Secondary and backscattered electron images were col-
lected at the same magnification. The acquired images
were imported into the image processing programmes
ilastik (Version 2) and ImageJ (v1.54f), where they were
calibrated, and a global scale bar was established for subse-
quent image analysis.
Statistical Analysis
Statistical treatment of the data was performed using
Statistical Package for Social Science” 13.0 (SPSS Inc.,
Chicago, IL, USA).
RESULTS AND DISCUSSION
Mineralogical Compositions of Talc
The diffractogram of the various talcs, as depicted in
Figure 1, depicts the peak assignments that correspond
to each mineral. Considering their distinct geological for-
mations and weathering processes, it was anticipated that
the talcs depicted in Figure 1 would exhibit variations in
mineralogy.
Talc, with the highest intensity peaks, was the principal
mineral in Indian talc, while United States talc, while con-
taining talc, also displayed peaks corresponding to clino-
chlore, goethite, serpentine, and magnesite. According to
Figure 1(a), US talc contains a lot of impurities and is thus
not as pure as Indian talc (Figure 1(b), which is the pur-
est form of the mineral). Table 3 displays the results of the
mineralogical quantification, which show that the Indian
talc contains approximately 100% talc, and that the US talc
contains 81% talc. This further indicates that the Indian
talc is of higher purity.
Calculation of the Aspect Ratio from XRD Data
The platy morphology of the talcs was determined using
the orientation of the surface or crystal plane obtained from
Table 2. Chemical compositions of different talcs
Talc SiO
4, %MgO, %Al
2 O
3, %Fe
2 O
3, %Loss on Fusion, %
India, I 62.1 30.0 0.04 2.0 5.4
United States, U 57.4 26.1 2.7 6.8 6.1