4
of the clearest examples of the “tunability” of the bio-sol-
vents is the ability to adjust the ratio of metabolites to tar-
get a penalty element. Figure 5 demonstrates how a subtle
change in the composition of a single bio-solvent resulted
in similar performance for alumina and silica removal and
upgraded the value metal, whereas one version (Bio-solvent
1A) resulted in significantly improved removal of a penalty
element. Similar optimization has also been observed with
temperature controls and with the amount of solid loading
to the bio-solvents. This work is on-going.
Tailings
The target elements for solubilization of the tailings mate-
rials were Mg and Ca, which were present in a range of
silicates including pyroxenes, chlorite, and feldspar, as
determined by XRD. Numerous studies promote the car-
bon capture potential present within mining tailings (such
as Bullock et al., 2021), and the search for viable methods
for economically processing tailings at the scale required
for carbon capture is ongoing. Testing was conducted on
tailings from three different mine sites, but generally, the
same type of ore was extracted and processed in the same
manner, and very small amounts of valuable metals like Cu
or Ni remained in the tailings. Several bio-solvents showed
a high affinity for Ca and Mg removal. The decrease in
the percent of CaO and MgO was similar to the reduc-
tion achieved by sulfuric acid after four days of treatment
(Figure 6 a,b).
Similar results were also observed for alumina and silica
(Figure 6 c,d). Importantly, the best-performing bio-sol-
vents did not impact the low concentrations of Cu and Ni
present in the tailings (reduced by less than 10%) showing
the capability for the bio-solvent to selectively dissolve the
Mg and Ca species over the value metal (Figure 6 e,f). This
selective solubilization is unlike the solubilization using sul-
furic acid which reduced the concentrations of Cu and Ni
by nearly 60% and 25%, respectively (Figure 6 e–f).
The bio-solvents were as effective as mineral acids,
such as sulfuric acid, at cation (Mg and Ca) removal, and
Figure 3. Gangue Removal from Rre using Bio-solvent 1A.
Beneficiation of 4 ore materials showed significant removal
of SiO
2 and Al
2 O
3 and an increase in the value metal after
just 2 hours of treatment and with only a single contact.
Error bars based on measurement of 12 samples (3 of each
ore type)
Figure 4. Increase in Gangue Removal with Decreasing
Ore Grade. Beneficiation was greater for ore materials
with a lower starting grade (higher gangue content). Grade
differences are between 4 ore materials, with 3 samples each
Figure 5. Improved Penalty Element Removal with Minor
Adjustment of the Bio-solvent. A small change in the ratio
of bio-solvent components resulted in improved penalty
element removal for one ore type, while other positive
impacts remain unchanged (removal of gangue and
upgrading of value metal). Error bars based on measurement
of 3 samples
of the clearest examples of the “tunability” of the bio-sol-
vents is the ability to adjust the ratio of metabolites to tar-
get a penalty element. Figure 5 demonstrates how a subtle
change in the composition of a single bio-solvent resulted
in similar performance for alumina and silica removal and
upgraded the value metal, whereas one version (Bio-solvent
1A) resulted in significantly improved removal of a penalty
element. Similar optimization has also been observed with
temperature controls and with the amount of solid loading
to the bio-solvents. This work is on-going.
Tailings
The target elements for solubilization of the tailings mate-
rials were Mg and Ca, which were present in a range of
silicates including pyroxenes, chlorite, and feldspar, as
determined by XRD. Numerous studies promote the car-
bon capture potential present within mining tailings (such
as Bullock et al., 2021), and the search for viable methods
for economically processing tailings at the scale required
for carbon capture is ongoing. Testing was conducted on
tailings from three different mine sites, but generally, the
same type of ore was extracted and processed in the same
manner, and very small amounts of valuable metals like Cu
or Ni remained in the tailings. Several bio-solvents showed
a high affinity for Ca and Mg removal. The decrease in
the percent of CaO and MgO was similar to the reduc-
tion achieved by sulfuric acid after four days of treatment
(Figure 6 a,b).
Similar results were also observed for alumina and silica
(Figure 6 c,d). Importantly, the best-performing bio-sol-
vents did not impact the low concentrations of Cu and Ni
present in the tailings (reduced by less than 10%) showing
the capability for the bio-solvent to selectively dissolve the
Mg and Ca species over the value metal (Figure 6 e,f). This
selective solubilization is unlike the solubilization using sul-
furic acid which reduced the concentrations of Cu and Ni
by nearly 60% and 25%, respectively (Figure 6 e–f).
The bio-solvents were as effective as mineral acids,
such as sulfuric acid, at cation (Mg and Ca) removal, and
Figure 3. Gangue Removal from Rre using Bio-solvent 1A.
Beneficiation of 4 ore materials showed significant removal
of SiO
2 and Al
2 O
3 and an increase in the value metal after
just 2 hours of treatment and with only a single contact.
Error bars based on measurement of 12 samples (3 of each
ore type)
Figure 4. Increase in Gangue Removal with Decreasing
Ore Grade. Beneficiation was greater for ore materials
with a lower starting grade (higher gangue content). Grade
differences are between 4 ore materials, with 3 samples each
Figure 5. Improved Penalty Element Removal with Minor
Adjustment of the Bio-solvent. A small change in the ratio
of bio-solvent components resulted in improved penalty
element removal for one ore type, while other positive
impacts remain unchanged (removal of gangue and
upgrading of value metal). Error bars based on measurement
of 3 samples