2464 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
The focus of this paper is to build on the previous test
work results and present a case study of a PGM bearing
ore during primary and secondary rougher flotation to
highlight particle size preferences, collector composition
and ratios of those components in the collector. The main
objective is to gain an understanding of the link between
mineralogy and collector chemistry. Batch flotation tests
were performed and the concentrates were mineralogi-
cally characterised for PGM and BMS using QEMSCAN
(quantitative evaluation of minerals by scanning electron
microscopy) and FEG MLA (Mineral Liberation Analyzer).
EXPERIMENTAL
Materials
A sample of Platreef ore was used for the mineralogical and
batch flotation case study. The head grade of the ore was
3.89 g/t 6E’s (Pt, Pd, Rh, Ru, Ir and Au), 0.06% Cu and
0.13% Ni.
Synthetic Water
The synthetic water used throughout the testwork con-
tained amounts of key ions similar to those normally
found in circuit water viz. Ca2+ 80ppm, Mg2+ 80ppm, Na+
135ppm, Cl– 270ppm, SO42– 250ppm, NO3– 135ppm,
CO32– 40ppm and TDS 990ppm. It was prepared by mix-
ing water having a specific conductance of 0.7μS cm–1 with
analytical grade quality chemicals. The synthetic water pro-
duced had an ionic strength of 3.5E-02.
Batch Flotation Test Work
A Platreef ore was used for the batch flotation test work
a two stage grind was employed with the primary grind
at 47% –75µm and the secondary grind at 80% –75µm.
Primary tailings solids were left to settle and excess water
was decanted prior to secondary milling. Concentrates
were collected for 10 minutes (3 and 7 minute intervals)
for the primary grind and 15 minutes (5 and 10 minute
intervals) for the secondary grind. Tailings were also col-
lected to produce grade-recovery curves.
Samples for mineralogical characterisation were pre-
pared by carrying out fifteen by two kilogram two stage
grind batch flotation tests for each condition tested to have
enough sample for mineralogical characterisation. Figure 1
shows the mineralogical characterisation sample protocol.
Two concentrates were collected for the primary grind
(47% –75µm) for 5 minutes each. The first concentrate was
used for mineralogical characterisation and the second con-
centrate was discarded. The tailings sample was reground
(80% –75µm) and a secondary grind concentrate was col-
lected for 5 minutes and used for mineralogical characteri-
sation, after that the batch flotation test was stopped.
A Denver flotation machine equipped with a 4.5 l cell
was used during the test work. The impeller was run at
900 rpm and the air was set at 7.5L/min. Reagent dosages
for the primary and secondary grind flotation for the col-
lectors tested were 160g/t and 152 g/t, respectively, for each
collector condition as depicted below
Figure 1. Mineralogical characterisation sample protocol
The focus of this paper is to build on the previous test
work results and present a case study of a PGM bearing
ore during primary and secondary rougher flotation to
highlight particle size preferences, collector composition
and ratios of those components in the collector. The main
objective is to gain an understanding of the link between
mineralogy and collector chemistry. Batch flotation tests
were performed and the concentrates were mineralogi-
cally characterised for PGM and BMS using QEMSCAN
(quantitative evaluation of minerals by scanning electron
microscopy) and FEG MLA (Mineral Liberation Analyzer).
EXPERIMENTAL
Materials
A sample of Platreef ore was used for the mineralogical and
batch flotation case study. The head grade of the ore was
3.89 g/t 6E’s (Pt, Pd, Rh, Ru, Ir and Au), 0.06% Cu and
0.13% Ni.
Synthetic Water
The synthetic water used throughout the testwork con-
tained amounts of key ions similar to those normally
found in circuit water viz. Ca2+ 80ppm, Mg2+ 80ppm, Na+
135ppm, Cl– 270ppm, SO42– 250ppm, NO3– 135ppm,
CO32– 40ppm and TDS 990ppm. It was prepared by mix-
ing water having a specific conductance of 0.7μS cm–1 with
analytical grade quality chemicals. The synthetic water pro-
duced had an ionic strength of 3.5E-02.
Batch Flotation Test Work
A Platreef ore was used for the batch flotation test work
a two stage grind was employed with the primary grind
at 47% –75µm and the secondary grind at 80% –75µm.
Primary tailings solids were left to settle and excess water
was decanted prior to secondary milling. Concentrates
were collected for 10 minutes (3 and 7 minute intervals)
for the primary grind and 15 minutes (5 and 10 minute
intervals) for the secondary grind. Tailings were also col-
lected to produce grade-recovery curves.
Samples for mineralogical characterisation were pre-
pared by carrying out fifteen by two kilogram two stage
grind batch flotation tests for each condition tested to have
enough sample for mineralogical characterisation. Figure 1
shows the mineralogical characterisation sample protocol.
Two concentrates were collected for the primary grind
(47% –75µm) for 5 minutes each. The first concentrate was
used for mineralogical characterisation and the second con-
centrate was discarded. The tailings sample was reground
(80% –75µm) and a secondary grind concentrate was col-
lected for 5 minutes and used for mineralogical characteri-
sation, after that the batch flotation test was stopped.
A Denver flotation machine equipped with a 4.5 l cell
was used during the test work. The impeller was run at
900 rpm and the air was set at 7.5L/min. Reagent dosages
for the primary and secondary grind flotation for the col-
lectors tested were 160g/t and 152 g/t, respectively, for each
collector condition as depicted below
Figure 1. Mineralogical characterisation sample protocol