XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2229
the overall grade of 27.20% Cu. By recovering the copper
from CST using the TLF process, the overall plant revenue
was increased by 27.6%. Most of the increase was due to an
increase in throughput from 5,000 tph to 6,239 tph in the
form of fresh feed and partly to the additional recovery of
copper from CST.
Figure 4 shows a TLF circuit for the recovery of copper
from a CST. A feed stream enters a high-shear tank, where
a collector, e.g., xanthate, was added to hydrophobize cop-
per-bearing minerals along with a small volume of recy-
clable oil, e.g., heptane, to selectively collect hydrophobic
particles and form an o/w Pickering emulsion (or agglom-
erates) under high-shear conditions. The product is trans-
ferred to the Morganizer, in which additional oil is added
to form a w/o Pickering emulsion by phase inversion in the
same manner as described in Figure 2. The emulsion drops
are then destabilized by the jigging motion of the lagging
materials placed on a screen to release the water drops along
with the entrained gangue minerals. The hydrophobic cop-
per-bearing minerals dispersed in the oil phase overflow
into a vacuum filter, in which spent oil is steam-stripped,
condensed, and recycled. Copper concentrates are practi-
cally free of surface moisture.
CONCLUSIONS
In two-liquid flotation (TLF), oil drops rather than air
bubbles are used to recover hydrophobic particles from an
aqueous phase by flotation. The process has been modified
such that spent oil can be readily recycled and the product
be free of entrained gangue minerals to obtain high-grade
concentrates free of surface moisture. The process has been
tested on fine coal wastes to produce ultraclean coal con-
taining less than 1% ash and moisture in the 2–4% range.
The modified TLF process has also been tested for copper
recovery from cleaner scavenger tails, which are usually
returned to rougher banks as circulating loads to recover
slow-floating particles. A better option may be to recover
the difficult-to-recover particles using the TLF process,
which will help increase both the recovery and throughput.
REFERENCES
Bessel, G. 1886, Berlin Patent 39,369. May 12.
Cassie, A. B. D., &Baxter, S. (1944). Wettability of porous
surfaces. Transactions of the Faraday society, 40,
546–551.
Everson, C.J., 1885, U.S. Patent 348,157. August 29.
Gupta, M., &Yoon, R. H. (2024). Maximizing the recov-
ery and throughput of a rougher flotation bank by
improving the recovery of composite particles. Minerals
Engineering, 207, 108545.
Gupta, M., Huang, K., &Yoon, R. H. (2022). Predicting
the recovery and grade of a rougher flotation circuit
from liberation data. Minerals Engineering, 188,
107853.
Gupta, M., Huang, K., Noble, A., &Yoon, R. H. (2023).
Improving the performance of a low-grade porphyry
copper ore flotation plant using a simulator that can
predict grade vs. recovery curves. Minerals Engineering,
202, 108243.
Haynes, W. 1860, British Patent 488, February 23.
Huang, K., &Yoon, R. H. (2019). Surface forces in the thin
liquid films (tlfs) of water confined between n-alkane
drops and hydrophobic gold surfaces. Langmuir,
35(48), 15681–15691.
Huang, K., Keles, S., Sherrell, I., Noble, A., &Yoon, R. H.
(2022). Development of a flotation simulator that can
predict grade vs. Recovery curves from mineral libera-
tion data. Minerals Engineering, 181, 107510.
Lai, R. W.M. and Fuerstenau, D.W., 1968. Liquid-liquid
extraction of ultrafine particles. Trans. AIME, 241:
549–555.
Pan, L., &Yoon, R. H. (2016). Measurement of hydro-
phobic forces in thin liquid films of water between
bubbles and xanthate-treated gold surfaces. Minerals
Engineering, 98, 240–250.
Potter, C.V., 1902, U.S. Patent 776,145. January 14.
Raleigh Jr, C. E., &Aplan, F. F. (1993). The use of mineral
matter dispersants and depressants during the flotation
of bituminous coals. In Coal science and technology
(Vol. 21, pp. 71–90). Elsevier.
Sivamohan, R. (1990). The problem of recovering very fine
particles in mineral processing—a review. International
Journal of Mineral Processing, 28(3–4), 247–288.
Sulman, H. L., &Kirkpatrick-Picard, H. F. (1905). U.S.
Patent No. 793,808. Washington, DC: U.S. Patent
and Trademark Office.
Yoon, R. H. (2016). U.S. Patent No. 9,518,241.
Washington, DC: U.S. Patent and Trademark Office.
Yoon, R. H., &Luttrell, G. H. (1995). U.S. Patent
No. 5,458,786. Washington, DC: U.S. Patent and
Trademark Office.
the overall grade of 27.20% Cu. By recovering the copper
from CST using the TLF process, the overall plant revenue
was increased by 27.6%. Most of the increase was due to an
increase in throughput from 5,000 tph to 6,239 tph in the
form of fresh feed and partly to the additional recovery of
copper from CST.
Figure 4 shows a TLF circuit for the recovery of copper
from a CST. A feed stream enters a high-shear tank, where
a collector, e.g., xanthate, was added to hydrophobize cop-
per-bearing minerals along with a small volume of recy-
clable oil, e.g., heptane, to selectively collect hydrophobic
particles and form an o/w Pickering emulsion (or agglom-
erates) under high-shear conditions. The product is trans-
ferred to the Morganizer, in which additional oil is added
to form a w/o Pickering emulsion by phase inversion in the
same manner as described in Figure 2. The emulsion drops
are then destabilized by the jigging motion of the lagging
materials placed on a screen to release the water drops along
with the entrained gangue minerals. The hydrophobic cop-
per-bearing minerals dispersed in the oil phase overflow
into a vacuum filter, in which spent oil is steam-stripped,
condensed, and recycled. Copper concentrates are practi-
cally free of surface moisture.
CONCLUSIONS
In two-liquid flotation (TLF), oil drops rather than air
bubbles are used to recover hydrophobic particles from an
aqueous phase by flotation. The process has been modified
such that spent oil can be readily recycled and the product
be free of entrained gangue minerals to obtain high-grade
concentrates free of surface moisture. The process has been
tested on fine coal wastes to produce ultraclean coal con-
taining less than 1% ash and moisture in the 2–4% range.
The modified TLF process has also been tested for copper
recovery from cleaner scavenger tails, which are usually
returned to rougher banks as circulating loads to recover
slow-floating particles. A better option may be to recover
the difficult-to-recover particles using the TLF process,
which will help increase both the recovery and throughput.
REFERENCES
Bessel, G. 1886, Berlin Patent 39,369. May 12.
Cassie, A. B. D., &Baxter, S. (1944). Wettability of porous
surfaces. Transactions of the Faraday society, 40,
546–551.
Everson, C.J., 1885, U.S. Patent 348,157. August 29.
Gupta, M., &Yoon, R. H. (2024). Maximizing the recov-
ery and throughput of a rougher flotation bank by
improving the recovery of composite particles. Minerals
Engineering, 207, 108545.
Gupta, M., Huang, K., &Yoon, R. H. (2022). Predicting
the recovery and grade of a rougher flotation circuit
from liberation data. Minerals Engineering, 188,
107853.
Gupta, M., Huang, K., Noble, A., &Yoon, R. H. (2023).
Improving the performance of a low-grade porphyry
copper ore flotation plant using a simulator that can
predict grade vs. recovery curves. Minerals Engineering,
202, 108243.
Haynes, W. 1860, British Patent 488, February 23.
Huang, K., &Yoon, R. H. (2019). Surface forces in the thin
liquid films (tlfs) of water confined between n-alkane
drops and hydrophobic gold surfaces. Langmuir,
35(48), 15681–15691.
Huang, K., Keles, S., Sherrell, I., Noble, A., &Yoon, R. H.
(2022). Development of a flotation simulator that can
predict grade vs. Recovery curves from mineral libera-
tion data. Minerals Engineering, 181, 107510.
Lai, R. W.M. and Fuerstenau, D.W., 1968. Liquid-liquid
extraction of ultrafine particles. Trans. AIME, 241:
549–555.
Pan, L., &Yoon, R. H. (2016). Measurement of hydro-
phobic forces in thin liquid films of water between
bubbles and xanthate-treated gold surfaces. Minerals
Engineering, 98, 240–250.
Potter, C.V., 1902, U.S. Patent 776,145. January 14.
Raleigh Jr, C. E., &Aplan, F. F. (1993). The use of mineral
matter dispersants and depressants during the flotation
of bituminous coals. In Coal science and technology
(Vol. 21, pp. 71–90). Elsevier.
Sivamohan, R. (1990). The problem of recovering very fine
particles in mineral processing—a review. International
Journal of Mineral Processing, 28(3–4), 247–288.
Sulman, H. L., &Kirkpatrick-Picard, H. F. (1905). U.S.
Patent No. 793,808. Washington, DC: U.S. Patent
and Trademark Office.
Yoon, R. H. (2016). U.S. Patent No. 9,518,241.
Washington, DC: U.S. Patent and Trademark Office.
Yoon, R. H., &Luttrell, G. H. (1995). U.S. Patent
No. 5,458,786. Washington, DC: U.S. Patent and
Trademark Office.