3628 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
was performed using Bruker’s EVA software, which features
the ICDD PDF-2 database. Phase quantification was per-
formed using the Rietveld refinement method in TOPAS
software. Refinement parameters included a background
fitting with a 4 to 6 order Chebyshev polynomial, sample
displacement correction, crystal structure refinement, i.e.,
cell parameters and crystallite size, preferential orientations
correction (on major phases only), and peak fitting using
Bruker-designed fundamental parameters (FP).
Liberation Analysis
Liberation analyses were performed on sized samples using
Zeiss’s Mineralogic system, which is based on a Zeiss Sigma
300 scanning electron microscope with a field emission
gun (FEG-SEM). This system allows to use backscattered
electrons (BSE) images and energy dispersive X-ray analyses
(EDS) to create digital mineral images and extract various
quantitative mineralogical information like mineral libera-
tion, association and morphological parameters of grains
and particles.
After the analysis, each particle is classified into three
liberation categories, depending on the degree of liberation
of the interest mineral (above 90 per cent, the particle is
liberated, between 30 per cent and 90 per cent, the particle
is classified as middling and below 30 per cent, the particle
is called locked). The overall liberation of the sample is then
computed as the weight of a specific mineral in liberated
particles, over the weight of the same mineral in all par-
ticles, as described in Equation (1).
Liberation
W W
W *100
W liberated middling locked
liberated =
++
(1)
where the weight (W) is calculated as the area of mineral
multiplied by their specific gravity.
Spiral Tests
The spirals tests were performed in pilot scale (batch mode)
using the closed-circuit apparatus presented in Figure 5.
Figure 4. Head sample PSD
Figure 5. Spirals tests apparatus
was performed using Bruker’s EVA software, which features
the ICDD PDF-2 database. Phase quantification was per-
formed using the Rietveld refinement method in TOPAS
software. Refinement parameters included a background
fitting with a 4 to 6 order Chebyshev polynomial, sample
displacement correction, crystal structure refinement, i.e.,
cell parameters and crystallite size, preferential orientations
correction (on major phases only), and peak fitting using
Bruker-designed fundamental parameters (FP).
Liberation Analysis
Liberation analyses were performed on sized samples using
Zeiss’s Mineralogic system, which is based on a Zeiss Sigma
300 scanning electron microscope with a field emission
gun (FEG-SEM). This system allows to use backscattered
electrons (BSE) images and energy dispersive X-ray analyses
(EDS) to create digital mineral images and extract various
quantitative mineralogical information like mineral libera-
tion, association and morphological parameters of grains
and particles.
After the analysis, each particle is classified into three
liberation categories, depending on the degree of liberation
of the interest mineral (above 90 per cent, the particle is
liberated, between 30 per cent and 90 per cent, the particle
is classified as middling and below 30 per cent, the particle
is called locked). The overall liberation of the sample is then
computed as the weight of a specific mineral in liberated
particles, over the weight of the same mineral in all par-
ticles, as described in Equation (1).
Liberation
W W
W *100
W liberated middling locked
liberated =
++
(1)
where the weight (W) is calculated as the area of mineral
multiplied by their specific gravity.
Spiral Tests
The spirals tests were performed in pilot scale (batch mode)
using the closed-circuit apparatus presented in Figure 5.
Figure 4. Head sample PSD
Figure 5. Spirals tests apparatus