XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3363
Flotation of lithium pegmatites by Weir (1963),
described good bench scale results but the results were not
replicated in a pilot plant. This experience was observed in
Western Australia some 50 years later.
It has been shown that lepidolite and other micaceous
minerals can be removed by a conventional amine float at
pH 2.7 with excellent results. (Bhappu &Ferstenau, 1964).
LEACHING OF CONCENTRATES
Naturally occurring alpha spodumene is a lithium alumin-
ium silicate mineral in feldspar and silica rocks. It is refrac-
tory and must be heated in a kiln at 1050 °C to convert the
alpha spodumene to beta spodumene followed by process-
ing with sulfuric acid at 250 °C to effect leach recovery.
The leach slurry is filtered and the leach residue is disposed
of as waste whilst the lithium sulfate liquor is reacted with
sodium carbonate to produce lithium carbonate which can
be purified further and processed to lithium hydroxide.
Extraction of beryllium from beryl ore involves both
(a) pyrometallurgical techniques through roasting of beryl
with Na2SiF6 followed by leaching of the roasted beryl
with commercial (dilute) H2SO4 (b) hydrometallurgical
processing techniques of beryl through direct leaching with
H2SO4 to produce directly a sulfate liquor. It has been dem-
onstrated that beryllium oxide (BeO) could be recovered
from the solution after the separation of silicon and alu-
minium via heat treatment and the formation of beryllium
hydroxide (Be(OH)2) via a neutralization treatment. Also,
now beryllium can be recovered using solvent extraction.
The lithium hydroxide must be 99.99% pure to be sold
as battery grade material. This very high purity requires a
complex chemical plant and numerous unit operations
(Figure 8). It takes many months to achieve the specifica-
tion when commissioning.
An overview of current and new processes by Welham
(2017) describes DMS and flotation as well as lithium
conversion processes. DMS is not sufficient alone and
Figure 7. Pilbara Minerals Flowsheet (METS Library)
Flotation of lithium pegmatites by Weir (1963),
described good bench scale results but the results were not
replicated in a pilot plant. This experience was observed in
Western Australia some 50 years later.
It has been shown that lepidolite and other micaceous
minerals can be removed by a conventional amine float at
pH 2.7 with excellent results. (Bhappu &Ferstenau, 1964).
LEACHING OF CONCENTRATES
Naturally occurring alpha spodumene is a lithium alumin-
ium silicate mineral in feldspar and silica rocks. It is refrac-
tory and must be heated in a kiln at 1050 °C to convert the
alpha spodumene to beta spodumene followed by process-
ing with sulfuric acid at 250 °C to effect leach recovery.
The leach slurry is filtered and the leach residue is disposed
of as waste whilst the lithium sulfate liquor is reacted with
sodium carbonate to produce lithium carbonate which can
be purified further and processed to lithium hydroxide.
Extraction of beryllium from beryl ore involves both
(a) pyrometallurgical techniques through roasting of beryl
with Na2SiF6 followed by leaching of the roasted beryl
with commercial (dilute) H2SO4 (b) hydrometallurgical
processing techniques of beryl through direct leaching with
H2SO4 to produce directly a sulfate liquor. It has been dem-
onstrated that beryllium oxide (BeO) could be recovered
from the solution after the separation of silicon and alu-
minium via heat treatment and the formation of beryllium
hydroxide (Be(OH)2) via a neutralization treatment. Also,
now beryllium can be recovered using solvent extraction.
The lithium hydroxide must be 99.99% pure to be sold
as battery grade material. This very high purity requires a
complex chemical plant and numerous unit operations
(Figure 8). It takes many months to achieve the specifica-
tion when commissioning.
An overview of current and new processes by Welham
(2017) describes DMS and flotation as well as lithium
conversion processes. DMS is not sufficient alone and
Figure 7. Pilbara Minerals Flowsheet (METS Library)