XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3317
ensure the feed was at approximately 60% solids and the
pH prior to TOFA addition was well under pH 8.3. High-
density conditioning was performed at pH 8.3 (adjusted
with NaOH if needed) with a 450 g/t dosage of 450 g/t of
TOFA and a power density of 37 W/L for 7 minutes. Prior
to flotation, the pulp was diluted to 35% solids and adjusted
to pH 8.5 with soda ash. Rougher flotation was performed
for a total of 3 minutes, the concentrate, and tailings were
dried and weighed. Representative sub-samples were taken
from each product and digested by sodium peroxide fusion
and submitted for lithium analysis by Inductively Coupled
Plasma Optical Emission Spectroscopy (ICP-OES) with
an Agilent 5110 ICP-OES in the analytical labs at SGS
in Lakefield, Ontario. All samples were also analyzed with
borate fusion X-ray Fluorescence (XRF) for Li, SiO2,
Al2O3, Fe2O3, MgO, CaO, K2O, TiO2, MnO, Cr2O3,
V2O5, Na2O, and P2O5.
RESULTS AND DISCUSSION
The two commercial TOFA collectors and four TOFA and
TOR blends in this investigation were evaluated in a series
of six flotation tests, all operated under identical conditions.
One additional test was performed where rougher flotation
was conducted at pH 9.25 instead of pH 8.5. The rougher
flotation results from the seven batch tests are presented
in Table 3, as well as in Figure 1 and 2. The objective of
the spodumene rougher flotation stage was to maximize
lithium concentrate grade and recovery while minimizing
recovery of iron-bearing silicates and other gangue miner-
als. The performance of potassium and sodium are included
as the main indicators of common silicate gangue minerals
found in pegmatite ores like micas and feldspars.
Overview of Rougher Flotation Performance
As shown in Table 3 and Figure 1, the highest rougher con-
centrate grade (4.65% Li2O) was produced using FA2 – the
collector with the lowest rosin content (0.8%) – at 94.8%
lithium recovery. This test also produced the highest Fe2O3
concentrate grade but the lowest K2O and Na2O grade and
recovery, indicating better rejection of silicate gangue than
iron-bearing minerals may be possible. FA1 also resulted in
high concentrate grade (4.52% Li2O), but at slightly lower
lithium recovery of 93.9% (when compared with FA2).
Comparing the Fe, K, and Na results of FA1 and FA2, less
iron was recovered with FA1 compared to FA2 but recovery
Table 2. Summary of reagents and collector blends with their respective rosin contents
Pure Reagents Collector Blends (Calculated)
Major Rosin Species FA1 FA2 NCY HYR
FA1
5% NCY
FA2
5% NCY
FA1
5% HYR
FA2
5% HYR
Palustric Acid — — 5.02 4.17 0.25 0.25 0.21 0.21
Abietic Acid 0.014 0.008 30.0 26.3 1.51 1.51 1.33 1.32
Neoabietic Acid — — 2.27 1.12 0.11 0.11 0.06 0.06
Dehydroabietic Acid 0.019 0.005 17.0 19.5 0.87 0.85 0.99 0.98
Secodehydroabietic acids 0.80 0.22 0.26 0.17 0.77 0.23 0.77 0.22
Isopimaric acid 0.59 0.17 2.34 2.82 0.68 0.28 0.70 0.30
Pimaric acid 0.40 0.09 1.44 1.76 0.45 0.15 0.47 0.17
8,15-Pimaric acid 0.31 0.08 2.91 2.69 0.44 0.22 0.43 0.21
Minor rosin acids species 0.26 0.23 20.8 21.5 1.29 1.26 1.32 1.29
Total Rosin Acid Content (%)2.40 0.80 82.0 80.0 6.38 4.86 6.28 4.76
PAN (Calculated) 0.014 0.008 37.3 31.6 1.88 1.87 1.59 1.59
Table 3. Summary of rougher flotation results
Reagent Tested
Assays (%)Distribution (%)
Li
2 O Fe
2 O
3 K
2 O Na
2 O Mass Li Fe K Na
FA1 4.52 2.13 0.74 1.57 22.3 93.9 67.1 13.3 8.0
FA2 4.65 2.20 0.73 1.48 22.7 94.8 67.6 13.2 7.7
FA1+5% NCY 4.39 2.07 0.78 1.64 23.6 94.7 68.7 14.6 8.9
FA2+5% NCY 4.33 2.13 0.79 1.68 24.6 96.6 73.6 15.6 9.6
FA1+5% NCY (pH 9.25) 4.35 2.17 0.80 1.66 23.3 94.0 69.5 14.9 8.9
FA1+5% HYR 4.41 2.07 0.80 1.70 23.6 95.2 68.0 15.0 9.2
FA2+5% HYR 4.03 1.93 0.88 1.96 25.9 97.0 72.2 18.2 11.8
Rosin
Acid
Content
(%)
ensure the feed was at approximately 60% solids and the
pH prior to TOFA addition was well under pH 8.3. High-
density conditioning was performed at pH 8.3 (adjusted
with NaOH if needed) with a 450 g/t dosage of 450 g/t of
TOFA and a power density of 37 W/L for 7 minutes. Prior
to flotation, the pulp was diluted to 35% solids and adjusted
to pH 8.5 with soda ash. Rougher flotation was performed
for a total of 3 minutes, the concentrate, and tailings were
dried and weighed. Representative sub-samples were taken
from each product and digested by sodium peroxide fusion
and submitted for lithium analysis by Inductively Coupled
Plasma Optical Emission Spectroscopy (ICP-OES) with
an Agilent 5110 ICP-OES in the analytical labs at SGS
in Lakefield, Ontario. All samples were also analyzed with
borate fusion X-ray Fluorescence (XRF) for Li, SiO2,
Al2O3, Fe2O3, MgO, CaO, K2O, TiO2, MnO, Cr2O3,
V2O5, Na2O, and P2O5.
RESULTS AND DISCUSSION
The two commercial TOFA collectors and four TOFA and
TOR blends in this investigation were evaluated in a series
of six flotation tests, all operated under identical conditions.
One additional test was performed where rougher flotation
was conducted at pH 9.25 instead of pH 8.5. The rougher
flotation results from the seven batch tests are presented
in Table 3, as well as in Figure 1 and 2. The objective of
the spodumene rougher flotation stage was to maximize
lithium concentrate grade and recovery while minimizing
recovery of iron-bearing silicates and other gangue miner-
als. The performance of potassium and sodium are included
as the main indicators of common silicate gangue minerals
found in pegmatite ores like micas and feldspars.
Overview of Rougher Flotation Performance
As shown in Table 3 and Figure 1, the highest rougher con-
centrate grade (4.65% Li2O) was produced using FA2 – the
collector with the lowest rosin content (0.8%) – at 94.8%
lithium recovery. This test also produced the highest Fe2O3
concentrate grade but the lowest K2O and Na2O grade and
recovery, indicating better rejection of silicate gangue than
iron-bearing minerals may be possible. FA1 also resulted in
high concentrate grade (4.52% Li2O), but at slightly lower
lithium recovery of 93.9% (when compared with FA2).
Comparing the Fe, K, and Na results of FA1 and FA2, less
iron was recovered with FA1 compared to FA2 but recovery
Table 2. Summary of reagents and collector blends with their respective rosin contents
Pure Reagents Collector Blends (Calculated)
Major Rosin Species FA1 FA2 NCY HYR
FA1
5% NCY
FA2
5% NCY
FA1
5% HYR
FA2
5% HYR
Palustric Acid — — 5.02 4.17 0.25 0.25 0.21 0.21
Abietic Acid 0.014 0.008 30.0 26.3 1.51 1.51 1.33 1.32
Neoabietic Acid — — 2.27 1.12 0.11 0.11 0.06 0.06
Dehydroabietic Acid 0.019 0.005 17.0 19.5 0.87 0.85 0.99 0.98
Secodehydroabietic acids 0.80 0.22 0.26 0.17 0.77 0.23 0.77 0.22
Isopimaric acid 0.59 0.17 2.34 2.82 0.68 0.28 0.70 0.30
Pimaric acid 0.40 0.09 1.44 1.76 0.45 0.15 0.47 0.17
8,15-Pimaric acid 0.31 0.08 2.91 2.69 0.44 0.22 0.43 0.21
Minor rosin acids species 0.26 0.23 20.8 21.5 1.29 1.26 1.32 1.29
Total Rosin Acid Content (%)2.40 0.80 82.0 80.0 6.38 4.86 6.28 4.76
PAN (Calculated) 0.014 0.008 37.3 31.6 1.88 1.87 1.59 1.59
Table 3. Summary of rougher flotation results
Reagent Tested
Assays (%)Distribution (%)
Li
2 O Fe
2 O
3 K
2 O Na
2 O Mass Li Fe K Na
FA1 4.52 2.13 0.74 1.57 22.3 93.9 67.1 13.3 8.0
FA2 4.65 2.20 0.73 1.48 22.7 94.8 67.6 13.2 7.7
FA1+5% NCY 4.39 2.07 0.78 1.64 23.6 94.7 68.7 14.6 8.9
FA2+5% NCY 4.33 2.13 0.79 1.68 24.6 96.6 73.6 15.6 9.6
FA1+5% NCY (pH 9.25) 4.35 2.17 0.80 1.66 23.3 94.0 69.5 14.9 8.9
FA1+5% HYR 4.41 2.07 0.80 1.70 23.6 95.2 68.0 15.0 9.2
FA2+5% HYR 4.03 1.93 0.88 1.96 25.9 97.0 72.2 18.2 11.8
Rosin
Acid
Content
(%)