XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2985
slurry passes through the top nozzle encounters pressur-
ized air (2). Small bubbles are generated under high pres-
sure and mixed with slurry in the confined space of the
Blast Tube, moving toward the bottom nozzle (5). Aerated
mixture reaches the speed of sound while passing through
the choke, where the pressure drops markedly according
to Bernoulli’s principle. In downstream of choke, as area
increases, pressure increases, and at this point, under the
influence of modest changes in pressure and the random
motion of water/gas molecules, shock waves (6) are gen-
erated. Following this phenomenon, an adverse pressure
gradient is created. This condition distorts the bubble to
a great extent and breaks down the small bubbles into
even smaller sizes. Afterward, vortex rings form around the
impingement bowl due to the impact of the slurry strike
against the bowl, which allows particles to be exposed to a
high shear zone several times. Loaded bubbles rose along
the flotation tank and were taken as a product (4) from the
launder.
Bubble particle attachment may occur in three contact
areas: in the plunging jet inside the Blast Tube, the shock-
wave downstream of the choke, and the formed vortex rings
in the impingement bowl (Jameson, 2010b).
The Concorde Cell Testing Program
The experimental work was conducted in a Concorde Cell
Lab Unit (20 L laboratory scale unit) located in Metso Pori
Research Center, as shown in Figure 2.
In the Concorde laboratory unit, 100% of the tail-
ings are recycled back into the feed of the cell. In batch
Concorde flotation tests, a certain volume of slurry (30 to
40 L) is transferred into the mixer (feed) tank and recircu-
lated with the tails until the given flotation time is reached.
The concentrate samples were collected over the entire
duration of the test and the remaining material forms the
tails sample.
In total 10 tests were conducted. Two different ores,
graphite, and metallurgical coal were used and tested with
different operating conditions, which are presented in
Table 1. Graphite feed grade is 40.4% and metallurgical
coal ash content is 23.2%. Two Blast Tubes of different sizes
and feed flow rates were used to study the effect of residence
time on the metallurgical performance of the Concorde
Cell. Blast Tube 1 had a higher volume than Blast Tube 2
and therefore Blast Tube 1 provides longer residence time
for the same operating conditions.
Figure 2. Concorde Cell Lab Unit
slurry passes through the top nozzle encounters pressur-
ized air (2). Small bubbles are generated under high pres-
sure and mixed with slurry in the confined space of the
Blast Tube, moving toward the bottom nozzle (5). Aerated
mixture reaches the speed of sound while passing through
the choke, where the pressure drops markedly according
to Bernoulli’s principle. In downstream of choke, as area
increases, pressure increases, and at this point, under the
influence of modest changes in pressure and the random
motion of water/gas molecules, shock waves (6) are gen-
erated. Following this phenomenon, an adverse pressure
gradient is created. This condition distorts the bubble to
a great extent and breaks down the small bubbles into
even smaller sizes. Afterward, vortex rings form around the
impingement bowl due to the impact of the slurry strike
against the bowl, which allows particles to be exposed to a
high shear zone several times. Loaded bubbles rose along
the flotation tank and were taken as a product (4) from the
launder.
Bubble particle attachment may occur in three contact
areas: in the plunging jet inside the Blast Tube, the shock-
wave downstream of the choke, and the formed vortex rings
in the impingement bowl (Jameson, 2010b).
The Concorde Cell Testing Program
The experimental work was conducted in a Concorde Cell
Lab Unit (20 L laboratory scale unit) located in Metso Pori
Research Center, as shown in Figure 2.
In the Concorde laboratory unit, 100% of the tail-
ings are recycled back into the feed of the cell. In batch
Concorde flotation tests, a certain volume of slurry (30 to
40 L) is transferred into the mixer (feed) tank and recircu-
lated with the tails until the given flotation time is reached.
The concentrate samples were collected over the entire
duration of the test and the remaining material forms the
tails sample.
In total 10 tests were conducted. Two different ores,
graphite, and metallurgical coal were used and tested with
different operating conditions, which are presented in
Table 1. Graphite feed grade is 40.4% and metallurgical
coal ash content is 23.2%. Two Blast Tubes of different sizes
and feed flow rates were used to study the effect of residence
time on the metallurgical performance of the Concorde
Cell. Blast Tube 1 had a higher volume than Blast Tube 2
and therefore Blast Tube 1 provides longer residence time
for the same operating conditions.
Figure 2. Concorde Cell Lab Unit