660 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Tall oil fatty acids (IMCD Australia Limited) and
sodium silicate (Chem-Supply Pty Ltd) were used as col-
lector and depressant, respectively. H2SO4 (Chem-supply
Ply, Ltd) and NaOH (Chem-supply Ply, Ltd) were used
pH regulators. Bore water and purified water from Western
Australia were used for comparison of REO flotation per-
formance. The typical composition of the main ions in the
bore water and nanofiltration purified water are shown in
Table 2 and Table 3. More detailed information about the
compositions of permeates from various water treatment
systems is reported elsewhere (Guerra et al., 2023).
Experimental Conditions and Procedures
The sample was crushed and then wet-milled in a rod mill
in the presence of 3 kg/t sodium silicate depressant. The
time of milling of 20 mins was determined based on the
desired particle size distribution of p80 of 38 µm to achieve
sufficient liberation. Flotation tests were conducted with
a bench scale mechanical flotation cell (Wemco). In this
study, 1 stage of rougher, 3 stages of scavenger and 2 stages
of cleaner flotations (Figure 2) were conducted to obtain
the final concentrate. The roughing and scavenging stages
were conducted using a 5 L flotation cell (20% solids) at
900 rpm while the cleaning stages were performed using
a 3 L flotation cell (10% solids) at 700 rpm. The air flow
rate was kept as 2.5 L/min during the experiments. The
flotation time for each stage was 3 mins. The reagent addi-
tion scheme used in this study is shown in Table 4. The pH
of the pulp was adjusted to 10 for all tests. The pulp was
made up with the desired water to establish the exact effect
of water quality on rare earth minerals flotation efficiency.
Table 2. Main cations contained in the bore water used in this study
Ca2+, mg/L Mg2+, mg/L Na+, mg/L K+, mg/L Zn2+, mg/L
160 180 1500 45 0.25
Table 3. Major ion concentration in the permeate after nanofiltration at 12 bar
Ca2+, mg/L Mg2+, mg/L Na+, mg/L SO42–, mg/L Cl–, mg/L
3.44 3.00 364 6.00 535
Figure 2. Flowsheet for the flotation of rare earth minerals
Table 4. Reagent addition scheme for flotation experiments
(pH for each stage was kept at 10)
Stage
Addition Rates (g/t)
NaOH Na
2 SiO
3 Tall Oil
Mill 1500 3000 0
Rougher/
Scavenger
300 600 3500
Cleaner 1 100 600 500
Cleaner 2 100 300 0
Total 2000 4500 4000
Tall oil fatty acids (IMCD Australia Limited) and
sodium silicate (Chem-Supply Pty Ltd) were used as col-
lector and depressant, respectively. H2SO4 (Chem-supply
Ply, Ltd) and NaOH (Chem-supply Ply, Ltd) were used
pH regulators. Bore water and purified water from Western
Australia were used for comparison of REO flotation per-
formance. The typical composition of the main ions in the
bore water and nanofiltration purified water are shown in
Table 2 and Table 3. More detailed information about the
compositions of permeates from various water treatment
systems is reported elsewhere (Guerra et al., 2023).
Experimental Conditions and Procedures
The sample was crushed and then wet-milled in a rod mill
in the presence of 3 kg/t sodium silicate depressant. The
time of milling of 20 mins was determined based on the
desired particle size distribution of p80 of 38 µm to achieve
sufficient liberation. Flotation tests were conducted with
a bench scale mechanical flotation cell (Wemco). In this
study, 1 stage of rougher, 3 stages of scavenger and 2 stages
of cleaner flotations (Figure 2) were conducted to obtain
the final concentrate. The roughing and scavenging stages
were conducted using a 5 L flotation cell (20% solids) at
900 rpm while the cleaning stages were performed using
a 3 L flotation cell (10% solids) at 700 rpm. The air flow
rate was kept as 2.5 L/min during the experiments. The
flotation time for each stage was 3 mins. The reagent addi-
tion scheme used in this study is shown in Table 4. The pH
of the pulp was adjusted to 10 for all tests. The pulp was
made up with the desired water to establish the exact effect
of water quality on rare earth minerals flotation efficiency.
Table 2. Main cations contained in the bore water used in this study
Ca2+, mg/L Mg2+, mg/L Na+, mg/L K+, mg/L Zn2+, mg/L
160 180 1500 45 0.25
Table 3. Major ion concentration in the permeate after nanofiltration at 12 bar
Ca2+, mg/L Mg2+, mg/L Na+, mg/L SO42–, mg/L Cl–, mg/L
3.44 3.00 364 6.00 535
Figure 2. Flowsheet for the flotation of rare earth minerals
Table 4. Reagent addition scheme for flotation experiments
(pH for each stage was kept at 10)
Stage
Addition Rates (g/t)
NaOH Na
2 SiO
3 Tall Oil
Mill 1500 3000 0
Rougher/
Scavenger
300 600 3500
Cleaner 1 100 600 500
Cleaner 2 100 300 0
Total 2000 4500 4000