3374 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
under oxalic acid leaching, highlighting the potential for
selective leaching. A comprehensive understanding of these
dissolution dynamics is crucial for optimizing extraction
processes in various industrial applications.
Selectivity Studies of Organic Acid Leaching Compared
with Sulfuric Acid
Organic acids are known to be more selective and good
chelating agents. After carrying out the experiments with
organic acids and comparing them with sulfuric acid, the
first objective was to check the Li extraction from all the
acids and see which of them gives the best results. As seen in
Figure 8(a), oxalic acid is the organic acid that gives the best
Li extraction, with very comparable rates as sulfuric acid,
at over 90% extraction in the 1st hour. The other organic
acids had relatively lower Li extraction, not attaining 90%
in the 24th hour. Looking at the speciation diagram in
Figure 9 (a), it can be seen that Li forms a stable complex
ion Li(ox)– which explains the high dissolution of Li in
oxalic acid. Similarly from Figure 9(b), a stable complex
ion LiSO4– is formed permitting a high Li extraction in
sulfuric acid, which explains why Li extraction is high in
this acid too. According to Ankit Verma et al., Li does not
only form stable complexes but simple oxalate compounds
as well [44].
The high Li extraction is of primordial importance,
however, selectivity also plays an instrumental role, as this
will reduce thermal and economic burdens downstream.
Ca and Mg which happen to be the main impurities in
this claystone had different extraction behaviors with the
different acids employed. Figure 8(b) shows the different
Ca extractions with the four acids, and it can be seen that
citric acid dissolves most of the Ca present in the 1st hour,
while tartaric acid extracts approximately 70% in 24 hours.
Figure 8. Dissolution of (a) Li, (b) calcium, and (c) Mg by different acids. 1M acid, 80 °C, 10 L/S (SA- sulfuric acid, OA –
oxalic acid, CA – citric acid, TA – tartaric acid)
under oxalic acid leaching, highlighting the potential for
selective leaching. A comprehensive understanding of these
dissolution dynamics is crucial for optimizing extraction
processes in various industrial applications.
Selectivity Studies of Organic Acid Leaching Compared
with Sulfuric Acid
Organic acids are known to be more selective and good
chelating agents. After carrying out the experiments with
organic acids and comparing them with sulfuric acid, the
first objective was to check the Li extraction from all the
acids and see which of them gives the best results. As seen in
Figure 8(a), oxalic acid is the organic acid that gives the best
Li extraction, with very comparable rates as sulfuric acid,
at over 90% extraction in the 1st hour. The other organic
acids had relatively lower Li extraction, not attaining 90%
in the 24th hour. Looking at the speciation diagram in
Figure 9 (a), it can be seen that Li forms a stable complex
ion Li(ox)– which explains the high dissolution of Li in
oxalic acid. Similarly from Figure 9(b), a stable complex
ion LiSO4– is formed permitting a high Li extraction in
sulfuric acid, which explains why Li extraction is high in
this acid too. According to Ankit Verma et al., Li does not
only form stable complexes but simple oxalate compounds
as well [44].
The high Li extraction is of primordial importance,
however, selectivity also plays an instrumental role, as this
will reduce thermal and economic burdens downstream.
Ca and Mg which happen to be the main impurities in
this claystone had different extraction behaviors with the
different acids employed. Figure 8(b) shows the different
Ca extractions with the four acids, and it can be seen that
citric acid dissolves most of the Ca present in the 1st hour,
while tartaric acid extracts approximately 70% in 24 hours.
Figure 8. Dissolution of (a) Li, (b) calcium, and (c) Mg by different acids. 1M acid, 80 °C, 10 L/S (SA- sulfuric acid, OA –
oxalic acid, CA – citric acid, TA – tartaric acid)