3468 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
a polyphenolic compound, TA displays diverse chemical
properties and can interact with substrates through cova-
lent bonds and non-covalent interactions such as hydrogen
bonding, hydrophobic association, metal coordination, etc
[20]. It is inferred that the adsorption of TA will change the
subsequent adsorption behaviors of ferric and PEO, thus
affecting the floc structures.
Figure 8 shows the UV-Vis spectra of different chemi-
cals and their mixtures in aqueous solutions. Over the scan-
ning range of 200–700 nm, the spectrum of ferric chloride
was found to overlap with the spectrum of ferric/PEO
mixtures, indicating that ferric did not interact with PEO.
Therefore, their synergistic effects in the filtration was lim-
ited. From UV-Vis spectra, it can clearly observe the com-
plexation between TA and ferric and PEO, respectively. A
new absorption band emerged on the TA+ferric spectrum
around 550 nm. The characteristic absorption peak of the
TA spectrum at 278 nm had a red shift upon mixing the
TA with PEO. In addition, on the UV-Vis spectrum of
TA+ferric/PEO, both the new bands and peak shifts were
found, indicating that both ferric and PEO have interacted
with TA and the formation of tri-component complexes.
Such a polymeric structure helps obtain unique floc prop-
erties in flocculation and efficient dewatering in pressure
filtration.
As illustrated from the schematic diagram in Figure 9,
the tannic acid played a positive role in the flocculation
filtration process to dewater the oil sands fine tailings. It
acted as a cross-linker, bridging the function of coagulants
(ferric chloride) and flocculants (PEO) through hydrogen
bonding and coordination interactions. The formed tri-
component polymeric network improved the shear stress
and compression resistance of flocs. These enhancements
in mechanical properties enabled the flocs not to beak and
yield more readily in pressure filtration than without TA
preconditioning, such a faster and sustained filtration effi-
ciency could be achieved.
Table 1. CHNS elemental analysis for tailings before and after conditioning with TA
Sample
Content, %
Nitrogen Carbon Hydrogen Sulfur
Tailings only 0.1490 ± 0.0011 9.6490 ± 0.0108 1.6363 ± 0.0070 1.0220 ± 0.0188
Tailings +25 mg/L TA 0.1563 ± 0.0007 10.2795 ± 0.0245 1.7375 ± 0.0047 0.9574 ± 0.0362
Tailings +100 mg/L TA 0.1581 ± 0.0011 10.6882 ± 0.0102 1.6813 ± 0.0035 1.0589 ± 0.0177
250 350 450 550 650 200 300 400 500 600 700
0.3
0.8
1.3
1.8
2.3
0.0
0.5
1.0
1.5
2.0
2.5
220 nm
316 nm
550 nm
278 nm
TA
TA+PEO
TA+Ferric
TA+Ferric/PEO
Ferric
PEO/Ferric
Wavelength (nm)
212 nm
Figure 8. UV-vis spectra of different chemicals and the interactions in aqueous solutions
Absorbance
a polyphenolic compound, TA displays diverse chemical
properties and can interact with substrates through cova-
lent bonds and non-covalent interactions such as hydrogen
bonding, hydrophobic association, metal coordination, etc
[20]. It is inferred that the adsorption of TA will change the
subsequent adsorption behaviors of ferric and PEO, thus
affecting the floc structures.
Figure 8 shows the UV-Vis spectra of different chemi-
cals and their mixtures in aqueous solutions. Over the scan-
ning range of 200–700 nm, the spectrum of ferric chloride
was found to overlap with the spectrum of ferric/PEO
mixtures, indicating that ferric did not interact with PEO.
Therefore, their synergistic effects in the filtration was lim-
ited. From UV-Vis spectra, it can clearly observe the com-
plexation between TA and ferric and PEO, respectively. A
new absorption band emerged on the TA+ferric spectrum
around 550 nm. The characteristic absorption peak of the
TA spectrum at 278 nm had a red shift upon mixing the
TA with PEO. In addition, on the UV-Vis spectrum of
TA+ferric/PEO, both the new bands and peak shifts were
found, indicating that both ferric and PEO have interacted
with TA and the formation of tri-component complexes.
Such a polymeric structure helps obtain unique floc prop-
erties in flocculation and efficient dewatering in pressure
filtration.
As illustrated from the schematic diagram in Figure 9,
the tannic acid played a positive role in the flocculation
filtration process to dewater the oil sands fine tailings. It
acted as a cross-linker, bridging the function of coagulants
(ferric chloride) and flocculants (PEO) through hydrogen
bonding and coordination interactions. The formed tri-
component polymeric network improved the shear stress
and compression resistance of flocs. These enhancements
in mechanical properties enabled the flocs not to beak and
yield more readily in pressure filtration than without TA
preconditioning, such a faster and sustained filtration effi-
ciency could be achieved.
Table 1. CHNS elemental analysis for tailings before and after conditioning with TA
Sample
Content, %
Nitrogen Carbon Hydrogen Sulfur
Tailings only 0.1490 ± 0.0011 9.6490 ± 0.0108 1.6363 ± 0.0070 1.0220 ± 0.0188
Tailings +25 mg/L TA 0.1563 ± 0.0007 10.2795 ± 0.0245 1.7375 ± 0.0047 0.9574 ± 0.0362
Tailings +100 mg/L TA 0.1581 ± 0.0011 10.6882 ± 0.0102 1.6813 ± 0.0035 1.0589 ± 0.0177
250 350 450 550 650 200 300 400 500 600 700
0.3
0.8
1.3
1.8
2.3
0.0
0.5
1.0
1.5
2.0
2.5
220 nm
316 nm
550 nm
278 nm
TA
TA+PEO
TA+Ferric
TA+Ferric/PEO
Ferric
PEO/Ferric
Wavelength (nm)
212 nm
Figure 8. UV-vis spectra of different chemicals and the interactions in aqueous solutions
Absorbance