XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2259
The topologies of the surfactants were prepared using
STaGE (Lundborg and Lindahl, 2015).
General Flotation Procedure
The study has been done as stepwise flotation with a Denver
laboratory flotation machine. The machine is modified and
equipped with an automatic froth-scraping device and a
double lip cell. Apparatus parameters are as follows: cell
volume (1.3L), solids in pulp (40%), rotor speed (900rpm),
airflow (2.5L/min), and scrape frequency (15 min–1).
The ore sample was added to the flotation cell and the
cell was filled up with synthetic process water. The pro-
cess water was prepared by adding appropriate amounts of
commercial salts to deionized water (Ca =170 mg/L, Mg
=20 mg/L, SO4 =440 mg/L, Cl =170 mg/L, HCO3 =
57 mg/L, pH =8). A water temperature of 19–22°C was
used as standard. The rotor speed was kept constant dur-
ing the test. The pulp was conditioned for 2 minutes with
300g/t of 2% aqueous dextrin solution as a depressant.
Then 1 wt-% collector solution was added. After 2 min-
utes of conditioning, the air and automatic froth skimmer
were switched on at the same time. The flotation contin-
ued for 3 minutes. Water was added continuously by a tube
below the pulp surface to keep the right pulp level. Another
portion of the collector was then added, and after 1 min-
ute of conditioning, a second froth product was collected
for three minutes. The last step was repeated twice. The
froth products and the remaining cell product were dried,
weighed, and analyzed for silicate mineral content, defined
as insoluble after cooking the sample in 25% hydrochloric
acid for 15 minutes. The content of acid-insoluble content
remaining in the cell product was then calculated after the
first, second, third, and (optional) fourth flotation steps.
General Frothing Procedure
The froth column is a system of multiple-graduated trans-
parent cylinders having an inner diameter of 15 cm. The
column is fitted with a variable-speed impeller that is
installed on the bottom of the column so that the pulp can
be stirred as in a real flotation cell. The froth column is sup-
plied with air through a tube located in the middle of the
turbulent zone near the impeller. The slurry (40% solids)
volume is set to 1.3 litres and the pulp density is similar
to those used in regular flotation tests. The impeller speed
(900 rpm) and airflow (2.5 L/min) are held constant dur-
ing tests. The column is also equipped with a linear scale to
measure the froth height. The typical test procedure is as
follows: (1) conditioning of the depressant (300g/t of 2%
aqueous dextrin) and mineral slurry for 2 minutes (2) con-
ditioning of the collector and mineral slurry for 2 minutes
(3) aeration at a constant rate of 2.5 L/min (4) the froth
formation is monitored for 2 minutes and recorded every
20 seconds, or until the froth height no longer increases,
however the minimum time is set to 2 minutes and (5) the
froth formation and froth breakage is followed by taking
pictures every 20 seconds during each process.
X-Ray Fluorescence (XRF)
All XRF analyses were performed on a PW2424 spectrom-
eter with sample changer, Magix series, an effect of 60
KV and 40 mA and a 27 mm mask. Collimator masks are
150 µm and for heavier elements, 700 µm. Measured lines
are K-alphas and for the calibration beads, 15 different cer-
tified standards were used.
RESULTS AND DISCUSSION
Flotation and Frothing
Four different ores, containing different amounts of silica
as impurity, and two different alkyletheramines (as bench-
mark collectors) were used. Polyesterpolyquat (a readily
biodegradable and low aqua-toxic silica collector bench-
mark for calcite flotation) was evaluated in this flotation
study and used as a comparative example.
The results (Table 1) show that the polyester polyqua-
ternary ammonium compound does not work very well.
When using this PEPQ the froth height remained very
low and, even at a 7,5-fold higher dosage of the collector,
very little siliceous material was removed from the iron ore.
Also, the acid-insoluble amount could not be removed to
the targeted level of 1.3%, meaning that PEPQ is extremely
unselective in the separation of silicates from iron ore.
Esters of aminohexanoic acid were evaluated also using
ores with high amounts of silica. The results in Table 2
demonstrate that the esters of aminohexanoic acid, when
used in a process to treat silica ores, continue to perform
well independent of the choice of ore type (Smolko-
Schwarzmayr et al., 2018).
A good performance in a froth flotation process is
ensured by a combination of mineralogical results and
froth characteristics. The froth characteristics include both
the height and stability of the froth. It is important in the
flotation process that the froth collapses as soon as the air
supply is stopped. Too stable froth will cause both entrain-
ment of particles and problems with the pumping of the
froth product. The entrainment, especially at a large scale,
will result in decreased selectivity (grade, recovery). The
problems with the froth product pumping will make the
process of flotation technically impossible.
Isodecyl-6-aminohexanoate sulphate, isooctyl-6-ami-
nohexanoate sulphate, and 2-ethylhexyl-6-aminohexanoate
The topologies of the surfactants were prepared using
STaGE (Lundborg and Lindahl, 2015).
General Flotation Procedure
The study has been done as stepwise flotation with a Denver
laboratory flotation machine. The machine is modified and
equipped with an automatic froth-scraping device and a
double lip cell. Apparatus parameters are as follows: cell
volume (1.3L), solids in pulp (40%), rotor speed (900rpm),
airflow (2.5L/min), and scrape frequency (15 min–1).
The ore sample was added to the flotation cell and the
cell was filled up with synthetic process water. The pro-
cess water was prepared by adding appropriate amounts of
commercial salts to deionized water (Ca =170 mg/L, Mg
=20 mg/L, SO4 =440 mg/L, Cl =170 mg/L, HCO3 =
57 mg/L, pH =8). A water temperature of 19–22°C was
used as standard. The rotor speed was kept constant dur-
ing the test. The pulp was conditioned for 2 minutes with
300g/t of 2% aqueous dextrin solution as a depressant.
Then 1 wt-% collector solution was added. After 2 min-
utes of conditioning, the air and automatic froth skimmer
were switched on at the same time. The flotation contin-
ued for 3 minutes. Water was added continuously by a tube
below the pulp surface to keep the right pulp level. Another
portion of the collector was then added, and after 1 min-
ute of conditioning, a second froth product was collected
for three minutes. The last step was repeated twice. The
froth products and the remaining cell product were dried,
weighed, and analyzed for silicate mineral content, defined
as insoluble after cooking the sample in 25% hydrochloric
acid for 15 minutes. The content of acid-insoluble content
remaining in the cell product was then calculated after the
first, second, third, and (optional) fourth flotation steps.
General Frothing Procedure
The froth column is a system of multiple-graduated trans-
parent cylinders having an inner diameter of 15 cm. The
column is fitted with a variable-speed impeller that is
installed on the bottom of the column so that the pulp can
be stirred as in a real flotation cell. The froth column is sup-
plied with air through a tube located in the middle of the
turbulent zone near the impeller. The slurry (40% solids)
volume is set to 1.3 litres and the pulp density is similar
to those used in regular flotation tests. The impeller speed
(900 rpm) and airflow (2.5 L/min) are held constant dur-
ing tests. The column is also equipped with a linear scale to
measure the froth height. The typical test procedure is as
follows: (1) conditioning of the depressant (300g/t of 2%
aqueous dextrin) and mineral slurry for 2 minutes (2) con-
ditioning of the collector and mineral slurry for 2 minutes
(3) aeration at a constant rate of 2.5 L/min (4) the froth
formation is monitored for 2 minutes and recorded every
20 seconds, or until the froth height no longer increases,
however the minimum time is set to 2 minutes and (5) the
froth formation and froth breakage is followed by taking
pictures every 20 seconds during each process.
X-Ray Fluorescence (XRF)
All XRF analyses were performed on a PW2424 spectrom-
eter with sample changer, Magix series, an effect of 60
KV and 40 mA and a 27 mm mask. Collimator masks are
150 µm and for heavier elements, 700 µm. Measured lines
are K-alphas and for the calibration beads, 15 different cer-
tified standards were used.
RESULTS AND DISCUSSION
Flotation and Frothing
Four different ores, containing different amounts of silica
as impurity, and two different alkyletheramines (as bench-
mark collectors) were used. Polyesterpolyquat (a readily
biodegradable and low aqua-toxic silica collector bench-
mark for calcite flotation) was evaluated in this flotation
study and used as a comparative example.
The results (Table 1) show that the polyester polyqua-
ternary ammonium compound does not work very well.
When using this PEPQ the froth height remained very
low and, even at a 7,5-fold higher dosage of the collector,
very little siliceous material was removed from the iron ore.
Also, the acid-insoluble amount could not be removed to
the targeted level of 1.3%, meaning that PEPQ is extremely
unselective in the separation of silicates from iron ore.
Esters of aminohexanoic acid were evaluated also using
ores with high amounts of silica. The results in Table 2
demonstrate that the esters of aminohexanoic acid, when
used in a process to treat silica ores, continue to perform
well independent of the choice of ore type (Smolko-
Schwarzmayr et al., 2018).
A good performance in a froth flotation process is
ensured by a combination of mineralogical results and
froth characteristics. The froth characteristics include both
the height and stability of the froth. It is important in the
flotation process that the froth collapses as soon as the air
supply is stopped. Too stable froth will cause both entrain-
ment of particles and problems with the pumping of the
froth product. The entrainment, especially at a large scale,
will result in decreased selectivity (grade, recovery). The
problems with the froth product pumping will make the
process of flotation technically impossible.
Isodecyl-6-aminohexanoate sulphate, isooctyl-6-ami-
nohexanoate sulphate, and 2-ethylhexyl-6-aminohexanoate