1638 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
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 reduction achieved by sulfuric
acid after four days of treatment (Figure 4). Similar to the
concentrate example, less solubilization of the value met-
als (Cu and Ni) occurred using the bio-solvents than with
sulfuric acid, where the concentrations of Cu and Ni were
reduced by nearly 60% and 25%, respectively (Figure 4).
The bio-solvents were effective at cation (Mg and Ca)
removal for two different mining applications, and present
a significant environmental advantage. Unlike strong acids,
the Mg and Ca are still labile in the bio-solvent solutions
and can be readily removed from solution. The bio-solvents
are not degraded during the solubilization which is essential
to allow for recovering both the bio-solvents and poten-
tially useful gangue minerals. We are currently refining our
methods for bio-solvent recovery.
BIO-CEMENTATION
With our bio-informatics database, we identified several
isolates with the genetic potential to perform MICP path-
ways and have been testing the ability of these organisms in
our lab. These organisms can generate carbonates that vary
in concentration, density and location on a particle and in
the carbonate crystal characteristics, which can result in a
wide range of geotechnical strengths. We have evaluated
numerous formulations for their ability to cement model
waste materials via the ureolytic pathway (Figure 5).
Using the same enzymatic formulation and by alter-
ing treatment conditions, we achieved differing amounts
of unconfined compressive strength for the same material,
as compared to a water control (Figure 6). The conditions
tested in Trial 2 resulted in a strength that was over 5-fold
higher than Trial 1and was achieved through altering a
few key conditions. This suggests that the strength of the
agglomerated material can be readily tuned based on the
application requirements. Early results also show a signifi-
cant improvement in other material specifications aside
from UCS using the enzymatic formulation. In addition
to testing several different ore and tailings materials, we are
currently working on evaluating other factors such as the
resistance of our bio-cemented material to variable tem-
perature and moisture conditions.
CO2 SEQUESTRATION
Combining our experimental work in bio-solubilization and
bio-cementation, we are developing technology to allow for
the enhanced carbonation of available Mg and Ca in several
model systems as a mechanism for carbon capture. Using
Figure 4. Two Bio-solvents Demonstrated Similar Solubilization of Tailings as Sulfuric Acid. Solubilization of two biosolvents
is shown compared to sulfuric acid after 4 days of treatment. The bio-solvents were selected to target CaO and MgO removal.
The bio-solvents demonstrated better retention of value metals, Cu and Ni
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 reduction achieved by sulfuric
acid after four days of treatment (Figure 4). Similar to the
concentrate example, less solubilization of the value met-
als (Cu and Ni) occurred using the bio-solvents than with
sulfuric acid, where the concentrations of Cu and Ni were
reduced by nearly 60% and 25%, respectively (Figure 4).
The bio-solvents were effective at cation (Mg and Ca)
removal for two different mining applications, and present
a significant environmental advantage. Unlike strong acids,
the Mg and Ca are still labile in the bio-solvent solutions
and can be readily removed from solution. The bio-solvents
are not degraded during the solubilization which is essential
to allow for recovering both the bio-solvents and poten-
tially useful gangue minerals. We are currently refining our
methods for bio-solvent recovery.
BIO-CEMENTATION
With our bio-informatics database, we identified several
isolates with the genetic potential to perform MICP path-
ways and have been testing the ability of these organisms in
our lab. These organisms can generate carbonates that vary
in concentration, density and location on a particle and in
the carbonate crystal characteristics, which can result in a
wide range of geotechnical strengths. We have evaluated
numerous formulations for their ability to cement model
waste materials via the ureolytic pathway (Figure 5).
Using the same enzymatic formulation and by alter-
ing treatment conditions, we achieved differing amounts
of unconfined compressive strength for the same material,
as compared to a water control (Figure 6). The conditions
tested in Trial 2 resulted in a strength that was over 5-fold
higher than Trial 1and was achieved through altering a
few key conditions. This suggests that the strength of the
agglomerated material can be readily tuned based on the
application requirements. Early results also show a signifi-
cant improvement in other material specifications aside
from UCS using the enzymatic formulation. In addition
to testing several different ore and tailings materials, we are
currently working on evaluating other factors such as the
resistance of our bio-cemented material to variable tem-
perature and moisture conditions.
CO2 SEQUESTRATION
Combining our experimental work in bio-solubilization and
bio-cementation, we are developing technology to allow for
the enhanced carbonation of available Mg and Ca in several
model systems as a mechanism for carbon capture. Using
Figure 4. Two Bio-solvents Demonstrated Similar Solubilization of Tailings as Sulfuric Acid. Solubilization of two biosolvents
is shown compared to sulfuric acid after 4 days of treatment. The bio-solvents were selected to target CaO and MgO removal.
The bio-solvents demonstrated better retention of value metals, Cu and Ni