XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1195
bastnaesite by depressing monazite using potassium alum
(KAl(SO4)2. 12H2O) (Ren, 2000). Although both are the
major rare earth bearing minerals, monazite is separated
from bastnaesite to avoid the costs of radioactive waste
disposal. By investigating the effect of potassium sulfate
(K2SO4) and aluminum sulfate (Al2(SO4)3) separately, they
concluded that the depression power of potassium alum
was solely due to the presence of aluminum ions the alu-
minum hydrolyzed species AlOH2+ and Al(OH)2+adsorb
on the polar surfaces of minerals, and hence increase their
hydrophilicity.
By comparing the floatation responses of monazite and
xenotime through small scale flotation tests with pure min-
erals it was found that monazite and xenotime exhibited
maximum floatability at pH 8.5 – 9 and 7 – 8 respectively
(Cheng, 1992). The maximum flotation of monazite coin-
cides with the optimum concentration of the rare earth
hydrated ions Ce(OH)2+ and La(OH)2+. Therefore, these
ions are believed to adsorb on the surface of monazite and
act as activation site for oleate adsorption.
In a system comprised of monazite, rutile, and zircon,
it was found that the flotation responses of the three miner-
als are very similar (Pavez and Perez,1993). They also con-
cluded that sodium oleate is a better collector as oppose to
pure hydroxamate or commercial hydroxamate. The addi-
tion of each of all three collector shifts the isoelectric point
if these minerals to more acidic pH, and the overall zeta
potential becomes more negative. It was also concluded
that separation of these minerals is made possible by the
use of sodium metasilicate as a depressant for rutile and
zircon (Pavez and Perez,1993). In another study on bench
scale flotation study of a Brazilian monazite ore, it was
found that an optimum concentration of monazite can be
achieved by either using 140 g/t of commercial hydroxa-
mate and 1200 g/t of sodium metasilicate, or with the use
of 525 g/t of sodium oleate and 1398 g/t of sodium meta-
silicate (Paves and Perez, 1994).
In a system of monazite, xenotime, ilmenite, zircon,
garnet, tourmaline, and some silicate minerals, it was
concluded that is possible to separate monazite and xeno-
time from the oxide and silicate minerals by flotation in
an alkaline environment using an amphoteric compound
(F74286) as collector. (Ozeren and Hutchinson, 1990) The
latter has a reverse behavior in acidic environment serving
to activate the flotation of ilmenite and silicates.
Through electrokinetic experiments and infrared spec-
troscopy studies, (Paves, et al., 1995) suggested that oleate
adsorbs physically on the surface of monazite at pH 3 and
pH 8. Octyl hydroxamate adsorbs chemically on monazite
at pH 9. Oleate adsorbs both physically and chemically on
bastnaesite at pH 9. Octyl hydroxamate chemically adsorbs
on bastnaesite at pH 9.3.
SUMMARY
Rare earth minerals are processed based on the deposit
and the specific minerals which they contain. Mines typi-
cally upgrade the ore before a hydrometallurgical process
is applied to obtain the separated rare earths. Common
upgrading methods are flotation and other physical separa-
tions such as gravity. This paper has reviewed the nature,
occurrence and physical separation of rare earth bearing
minerals monazite and bastnaesite for rare earth production.
BIBLIOGRAPHY
Bastnaesite Beneficiation Resources
Assis, S., et al., 1996, “Utilization of Hydroxamates in
Minerals Froth Flotation, Minerals Engineering, vol. 9,
no. 1, pp. 103–114.
Abaka-Wood, G. B., Addai-Mensah, J. &Skinner, W.,
2016, Review of Flotation and Physical Separation
of Rare Earth Element Minerals, 4th UMaT Biennial
International Mining and Mineral Conference,
pp. MR 55–62.
Anderson, C.D., 2015, Improved understanding of rare
earth surface chemistry and its application to froth
flotation, Kroll Institute for Extractive Metallurgy,
Colorado School of Mines, PhD Thesis.
Anderson, C.D., Taylor, P. and Anderson, C.G. 2017, Rare
Earth Flotation Fundamentals: A Review, American
Journal of Engineering Research, e-ISSN: 2320–0847
p-ISSN :2320–0936 Volume 6, Issue 11, 12 pgs.
Chapelski, Jr., R. et al., 2020, “A Molecular Scale Approach
to Rare earth Beneficiation: Thinking Small to Avoid
Large Losses,” iScience, vol 23, no. 9.
Everly, D., 2018, “Surface Chemistry of Novel Collectors
and their Application to Froth Flotation of Rare Earth
Minerals,” MSc Thesis, Golden, CO.
Everly, D., Anderson, C., Popova, S., Bryantsev, V. &
Moyer, B., 2021. Beneficiation of Bastnaesite Ore with
New Flotation Collector Ligands, Aspects Min Miner
Sci. 7(2). AMMS. 000657.
Fuerstenau, D., 1983, “the adsoprtion of hydroxamate of
semi-soluble mineral. Part I: Adsorption on Barite,
Calcite and Bastnaesite,” Colloids and Surfaces, vol. 8
no. 2, pp. 103–119.
Gupta, C. K., &Chiranjib, K., 2016, “Introduction” in
Extractive Metallurgy of Rare Earths, Boca Raton,
Florida, CRC Press, pg 1.
bastnaesite by depressing monazite using potassium alum
(KAl(SO4)2. 12H2O) (Ren, 2000). Although both are the
major rare earth bearing minerals, monazite is separated
from bastnaesite to avoid the costs of radioactive waste
disposal. By investigating the effect of potassium sulfate
(K2SO4) and aluminum sulfate (Al2(SO4)3) separately, they
concluded that the depression power of potassium alum
was solely due to the presence of aluminum ions the alu-
minum hydrolyzed species AlOH2+ and Al(OH)2+adsorb
on the polar surfaces of minerals, and hence increase their
hydrophilicity.
By comparing the floatation responses of monazite and
xenotime through small scale flotation tests with pure min-
erals it was found that monazite and xenotime exhibited
maximum floatability at pH 8.5 – 9 and 7 – 8 respectively
(Cheng, 1992). The maximum flotation of monazite coin-
cides with the optimum concentration of the rare earth
hydrated ions Ce(OH)2+ and La(OH)2+. Therefore, these
ions are believed to adsorb on the surface of monazite and
act as activation site for oleate adsorption.
In a system comprised of monazite, rutile, and zircon,
it was found that the flotation responses of the three miner-
als are very similar (Pavez and Perez,1993). They also con-
cluded that sodium oleate is a better collector as oppose to
pure hydroxamate or commercial hydroxamate. The addi-
tion of each of all three collector shifts the isoelectric point
if these minerals to more acidic pH, and the overall zeta
potential becomes more negative. It was also concluded
that separation of these minerals is made possible by the
use of sodium metasilicate as a depressant for rutile and
zircon (Pavez and Perez,1993). In another study on bench
scale flotation study of a Brazilian monazite ore, it was
found that an optimum concentration of monazite can be
achieved by either using 140 g/t of commercial hydroxa-
mate and 1200 g/t of sodium metasilicate, or with the use
of 525 g/t of sodium oleate and 1398 g/t of sodium meta-
silicate (Paves and Perez, 1994).
In a system of monazite, xenotime, ilmenite, zircon,
garnet, tourmaline, and some silicate minerals, it was
concluded that is possible to separate monazite and xeno-
time from the oxide and silicate minerals by flotation in
an alkaline environment using an amphoteric compound
(F74286) as collector. (Ozeren and Hutchinson, 1990) The
latter has a reverse behavior in acidic environment serving
to activate the flotation of ilmenite and silicates.
Through electrokinetic experiments and infrared spec-
troscopy studies, (Paves, et al., 1995) suggested that oleate
adsorbs physically on the surface of monazite at pH 3 and
pH 8. Octyl hydroxamate adsorbs chemically on monazite
at pH 9. Oleate adsorbs both physically and chemically on
bastnaesite at pH 9. Octyl hydroxamate chemically adsorbs
on bastnaesite at pH 9.3.
SUMMARY
Rare earth minerals are processed based on the deposit
and the specific minerals which they contain. Mines typi-
cally upgrade the ore before a hydrometallurgical process
is applied to obtain the separated rare earths. Common
upgrading methods are flotation and other physical separa-
tions such as gravity. This paper has reviewed the nature,
occurrence and physical separation of rare earth bearing
minerals monazite and bastnaesite for rare earth production.
BIBLIOGRAPHY
Bastnaesite Beneficiation Resources
Assis, S., et al., 1996, “Utilization of Hydroxamates in
Minerals Froth Flotation, Minerals Engineering, vol. 9,
no. 1, pp. 103–114.
Abaka-Wood, G. B., Addai-Mensah, J. &Skinner, W.,
2016, Review of Flotation and Physical Separation
of Rare Earth Element Minerals, 4th UMaT Biennial
International Mining and Mineral Conference,
pp. MR 55–62.
Anderson, C.D., 2015, Improved understanding of rare
earth surface chemistry and its application to froth
flotation, Kroll Institute for Extractive Metallurgy,
Colorado School of Mines, PhD Thesis.
Anderson, C.D., Taylor, P. and Anderson, C.G. 2017, Rare
Earth Flotation Fundamentals: A Review, American
Journal of Engineering Research, e-ISSN: 2320–0847
p-ISSN :2320–0936 Volume 6, Issue 11, 12 pgs.
Chapelski, Jr., R. et al., 2020, “A Molecular Scale Approach
to Rare earth Beneficiation: Thinking Small to Avoid
Large Losses,” iScience, vol 23, no. 9.
Everly, D., 2018, “Surface Chemistry of Novel Collectors
and their Application to Froth Flotation of Rare Earth
Minerals,” MSc Thesis, Golden, CO.
Everly, D., Anderson, C., Popova, S., Bryantsev, V. &
Moyer, B., 2021. Beneficiation of Bastnaesite Ore with
New Flotation Collector Ligands, Aspects Min Miner
Sci. 7(2). AMMS. 000657.
Fuerstenau, D., 1983, “the adsoprtion of hydroxamate of
semi-soluble mineral. Part I: Adsorption on Barite,
Calcite and Bastnaesite,” Colloids and Surfaces, vol. 8
no. 2, pp. 103–119.
Gupta, C. K., &Chiranjib, K., 2016, “Introduction” in
Extractive Metallurgy of Rare Earths, Boca Raton,
Florida, CRC Press, pg 1.