XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3463
time was recorded using a balance that connected to the
computer and graphing software (Figure 1). After 30 min,
the compressed air was stopped and the rest tailings materi-
als were unloaded and weighed in an aluminum container,
which was then placed in an oven. After drying, the solid
content (wt %)in the filter cake was determined.
Characterization Methods
The specific resistance to filtration (SRF) was used to char-
acterize the filter cake resistance. SRF was obtained by per-
forming the constant pressure vacuum filtration with the
same chemical conditions as Millipore filtration and was
calculated based on Darcy’s law [16]. The floc size distri-
bution was measured using the focused beam reflectance
measurement (FBRM, G400) technique with different
chemical schemes. The sediment volume was measured in
the settling tests along with settling time, and it was used to
evaluate the compressibility of flocculated solids aggregates.
A Malvern Kinexus Rheometer was used to measure the
shear stress of flocs formed by different chemicals. In addi-
tion, we used a Flash 2000 CHNS/O elemental analyzer to
measure the adsorption of tannic acid on solids in the tail-
ing slurry. The complexation reactions between tannic acid
and ferric chloride/PEO were characterized by a UV-Vis
spectrophotometer (Perkin Elmer).
RESULTS AND DISCUSSION
Pressure Filtration Results
Figure 2 shows the pressure filtration curves of oil sands
tailings within 30 min when conditioning with different
chemicals. The tailings without chemical treatment were
extremely difficult to dewater, as can be seen from the very
bottom curve that less than 20 grams of filtrate were col-
lected with 250 g raw tailings. This was largely attributed to
the large amount of fine clays contained in oil sands tailings
[17]. The individual use of ferric chloride and PEO was
found to increase the filtration, however, the 5 kg/t ferric
or 1 kg/t PEO was not very effective because the filtrate
increment was limited especially PEO. One reason was
that ferric and PEO may not be at their optimum dosages,
and in the present work, we did not aim to find the opti-
mized chemical dosages. The combined use of ferric and
PEO obtained 56 grams of filtrate, better than that when
they were individually used. It is interesting to find that the
introduction of tannic acid in the tailing slurry benefited
the filtration performance whether it was used with PEO
Figure 1. Chemical conditioning equipment and pressure filtration unit setup
time was recorded using a balance that connected to the
computer and graphing software (Figure 1). After 30 min,
the compressed air was stopped and the rest tailings materi-
als were unloaded and weighed in an aluminum container,
which was then placed in an oven. After drying, the solid
content (wt %)in the filter cake was determined.
Characterization Methods
The specific resistance to filtration (SRF) was used to char-
acterize the filter cake resistance. SRF was obtained by per-
forming the constant pressure vacuum filtration with the
same chemical conditions as Millipore filtration and was
calculated based on Darcy’s law [16]. The floc size distri-
bution was measured using the focused beam reflectance
measurement (FBRM, G400) technique with different
chemical schemes. The sediment volume was measured in
the settling tests along with settling time, and it was used to
evaluate the compressibility of flocculated solids aggregates.
A Malvern Kinexus Rheometer was used to measure the
shear stress of flocs formed by different chemicals. In addi-
tion, we used a Flash 2000 CHNS/O elemental analyzer to
measure the adsorption of tannic acid on solids in the tail-
ing slurry. The complexation reactions between tannic acid
and ferric chloride/PEO were characterized by a UV-Vis
spectrophotometer (Perkin Elmer).
RESULTS AND DISCUSSION
Pressure Filtration Results
Figure 2 shows the pressure filtration curves of oil sands
tailings within 30 min when conditioning with different
chemicals. The tailings without chemical treatment were
extremely difficult to dewater, as can be seen from the very
bottom curve that less than 20 grams of filtrate were col-
lected with 250 g raw tailings. This was largely attributed to
the large amount of fine clays contained in oil sands tailings
[17]. The individual use of ferric chloride and PEO was
found to increase the filtration, however, the 5 kg/t ferric
or 1 kg/t PEO was not very effective because the filtrate
increment was limited especially PEO. One reason was
that ferric and PEO may not be at their optimum dosages,
and in the present work, we did not aim to find the opti-
mized chemical dosages. The combined use of ferric and
PEO obtained 56 grams of filtrate, better than that when
they were individually used. It is interesting to find that the
introduction of tannic acid in the tailing slurry benefited
the filtration performance whether it was used with PEO
Figure 1. Chemical conditioning equipment and pressure filtration unit setup