XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2273
CONCLUSIONS
We performed a study to understand the collecting proper-
ties of two biosurfactants ASL and LSL in comparison to
BHA and NaOl. Even though BHA and NaOl achieve the
best results in the flotation of ultrafine hematite, malachite,
and ceria from their synthetic mineral mixtures, ASL and
LSL hold a promise as green collectors of the ultrafine metal
oxides. At pH 5 and 10, they separate 70 and 75% ultrafine
hematite and malachite from ultrafine quartz, respectively,
while their performance is not affected by the particle size.
At pH 6.4–6.9, both the biosurfactants are adsorbed on
hematite and malachite through their sophorose group,
demonstrating a higher affinity to malachite. The poorer
general performance of DDM, which was studied for com-
parison, is explained by its higher adsorption density which
results in the bilayer adsorption.
The separation of hematite from ceria with BHA and
the biosurfactants is adversely affected by ceric ions, sug-
gesting that the ageing of the REM feed can play a critical
role in its floatability. The adverse effect of the ceria oxi-
dation is explained by the suppression of the surfactant
adsorption, which is associated with CeIII-OH groups.
Overall, our results indicate that the interaction of
the biosurfactants with the metal oxides goes beyond the
oversimplified model of their physi- and chemisorption. It
includes surface precipitation of surfactant-metal complexes
as in the case of ASL and hematite and a redox reaction
as in the case of ASL and LSL and ceria. These additional
interactions open a new way for tuning selectivity of the
biosurfactants to minerals in froth flotation.
Toward assessing the viability of the biosurfactants in
real ore flotation, it is important to understand their inter-
action with a broader range of gangue minerals associated
with metal oxide ores, including calcite and aluminosili-
cates, and develop strategies to reject gangues by employing
the flotation kinetics and depressants/regulators.
ACKNOWLEDGMENTS
We acknowledge the financial support of the Research
Council of Norway (NFR), FRINATEK Project No.:
274691, and the Department of Geoscience and Petroleum,
NTNU. We thank Bio Base Europe Pilot Plant and Rana
Gruber ASA for providing biosurfactants and hematite,
respectively. We also thank Laurentius Tijhuis for the
XRD and ICP-MS analyses, and Jakob Vinje for the XPS
measurements.
REFERENCES
[1] Chernyshova I, Slabov V, Kota HR. Emerging
application of biosurfactants in metal extraction.
Current Opinion in Colloid &Interface Science.
2023 68:101763. doi: 10.1016/j.cocis.2023.101763.
[2] Sivamohan R. The problem of recovering very
fine particles in mineral processing—A review.
Int J Miner Process. 1990 28(3–4):247–88. doi:
10.1016/0301-7516(90)90046-2.
[3] Chelgani SC, Rudolph M, Leistner T, Gutzmer J,
Peuker UA. A review of rare earth minerals flota-
tion: Monazite and xenotime. International Journal
of Mining Science and Technology. 2015 25(6):877–
83. doi: doi: 10.1016/j.ijmst.2015.09.002.
[4] Abaka-Wood GB, Addai-Mensah J, Skinner W. The
Use of Mining Tailings as Analog of Rare Earth
Elements Resources: Part 1 – Characterization and
Preliminary Separation. Miner Process Extr Metall Rev.
2021:1–15. doi: 10.1080/08827508.2021.1920410.
[5] Alcalde J, Kelm U, Vergara D. Historical assess-
ment of metal recovery potential from old mine
tailings: A study case for porphyry copper tailings,
Chile. Miner Eng. 2018 127:334–8. doi: 10.1016/j.
mineng.2018.04.022.
[6] Kunal Ahuja SB: Biosurfactants Market. https://www
.gminsights.com/industry-analysis/biosurfactants
-market-report (2023). Accessed.
[7] Hu X, Subramanian K, Wang H, Roelants SLKW,
To MH, Soetaert W, et al. Guiding environmental
sustainability of emerging bioconversion technol-
ogy for waste-derived sophorolipid production by
adopting a dynamic life cycle assessment (dLCA)
approach. Environ Pollut. 2021 269. doi: 10.1016
/j.envpol.2020.116101.
[8] Hu X, Subramanian K, Wang H, Roelants SLKW,
Soetaert W, Kaur G, et al. Bioconversion of Food
Waste to produce Industrial-scale Sophorolipid Syrup
and Crystals: dynamic Life Cycle Assessment (dLCA)
of Emerging Biotechnologies. Bioresour Technol.
2021 337. doi: 10.1016/j.biortech.2021.125474.
[9] Dierickx S, Castelein M, Remmery J, De Clercq V,
Lodens S, Baccile N, et al. From bumblebee to bio-
economy: Recent developments and perspectives for
sophorolipid biosynthesis. Biotechnol Adv. 2021.
doi: 10.1016/j.biotechadv.2021.107788.
CONCLUSIONS
We performed a study to understand the collecting proper-
ties of two biosurfactants ASL and LSL in comparison to
BHA and NaOl. Even though BHA and NaOl achieve the
best results in the flotation of ultrafine hematite, malachite,
and ceria from their synthetic mineral mixtures, ASL and
LSL hold a promise as green collectors of the ultrafine metal
oxides. At pH 5 and 10, they separate 70 and 75% ultrafine
hematite and malachite from ultrafine quartz, respectively,
while their performance is not affected by the particle size.
At pH 6.4–6.9, both the biosurfactants are adsorbed on
hematite and malachite through their sophorose group,
demonstrating a higher affinity to malachite. The poorer
general performance of DDM, which was studied for com-
parison, is explained by its higher adsorption density which
results in the bilayer adsorption.
The separation of hematite from ceria with BHA and
the biosurfactants is adversely affected by ceric ions, sug-
gesting that the ageing of the REM feed can play a critical
role in its floatability. The adverse effect of the ceria oxi-
dation is explained by the suppression of the surfactant
adsorption, which is associated with CeIII-OH groups.
Overall, our results indicate that the interaction of
the biosurfactants with the metal oxides goes beyond the
oversimplified model of their physi- and chemisorption. It
includes surface precipitation of surfactant-metal complexes
as in the case of ASL and hematite and a redox reaction
as in the case of ASL and LSL and ceria. These additional
interactions open a new way for tuning selectivity of the
biosurfactants to minerals in froth flotation.
Toward assessing the viability of the biosurfactants in
real ore flotation, it is important to understand their inter-
action with a broader range of gangue minerals associated
with metal oxide ores, including calcite and aluminosili-
cates, and develop strategies to reject gangues by employing
the flotation kinetics and depressants/regulators.
ACKNOWLEDGMENTS
We acknowledge the financial support of the Research
Council of Norway (NFR), FRINATEK Project No.:
274691, and the Department of Geoscience and Petroleum,
NTNU. We thank Bio Base Europe Pilot Plant and Rana
Gruber ASA for providing biosurfactants and hematite,
respectively. We also thank Laurentius Tijhuis for the
XRD and ICP-MS analyses, and Jakob Vinje for the XPS
measurements.
REFERENCES
[1] Chernyshova I, Slabov V, Kota HR. Emerging
application of biosurfactants in metal extraction.
Current Opinion in Colloid &Interface Science.
2023 68:101763. doi: 10.1016/j.cocis.2023.101763.
[2] Sivamohan R. The problem of recovering very
fine particles in mineral processing—A review.
Int J Miner Process. 1990 28(3–4):247–88. doi:
10.1016/0301-7516(90)90046-2.
[3] Chelgani SC, Rudolph M, Leistner T, Gutzmer J,
Peuker UA. A review of rare earth minerals flota-
tion: Monazite and xenotime. International Journal
of Mining Science and Technology. 2015 25(6):877–
83. doi: doi: 10.1016/j.ijmst.2015.09.002.
[4] Abaka-Wood GB, Addai-Mensah J, Skinner W. The
Use of Mining Tailings as Analog of Rare Earth
Elements Resources: Part 1 – Characterization and
Preliminary Separation. Miner Process Extr Metall Rev.
2021:1–15. doi: 10.1080/08827508.2021.1920410.
[5] Alcalde J, Kelm U, Vergara D. Historical assess-
ment of metal recovery potential from old mine
tailings: A study case for porphyry copper tailings,
Chile. Miner Eng. 2018 127:334–8. doi: 10.1016/j.
mineng.2018.04.022.
[6] Kunal Ahuja SB: Biosurfactants Market. https://www
.gminsights.com/industry-analysis/biosurfactants
-market-report (2023). Accessed.
[7] Hu X, Subramanian K, Wang H, Roelants SLKW,
To MH, Soetaert W, et al. Guiding environmental
sustainability of emerging bioconversion technol-
ogy for waste-derived sophorolipid production by
adopting a dynamic life cycle assessment (dLCA)
approach. Environ Pollut. 2021 269. doi: 10.1016
/j.envpol.2020.116101.
[8] Hu X, Subramanian K, Wang H, Roelants SLKW,
Soetaert W, Kaur G, et al. Bioconversion of Food
Waste to produce Industrial-scale Sophorolipid Syrup
and Crystals: dynamic Life Cycle Assessment (dLCA)
of Emerging Biotechnologies. Bioresour Technol.
2021 337. doi: 10.1016/j.biortech.2021.125474.
[9] Dierickx S, Castelein M, Remmery J, De Clercq V,
Lodens S, Baccile N, et al. From bumblebee to bio-
economy: Recent developments and perspectives for
sophorolipid biosynthesis. Biotechnol Adv. 2021.
doi: 10.1016/j.biotechadv.2021.107788.