2986 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
The Effect of Residence Time
In Figure 3, the effect of Blast Tube volume on graphite
flotation kinetics and metallurgical performance is demon-
strated. Throughout the paper, Blast Tube is abbreviated as
BT in graph labels and the number next to it represents
the size of the Blast Tube. T1 and T4 show an impact of
the Blast Tube volume at high solids %whereas T2 and T5
at low solids %.Regardless of pulp solids, it can be clearly
seen from the figures that the flotation kinetics are faster
and the recoveries are higher with the lower volume of Blast
Tube. That means that reducing the residence time in the
Blast Tube leads to faster flotation kinetics. It can be also
deduced that at 20% solids, the effect of Blast Tube volume
is more obvious compared to its effect at 5% solids.
Grade recovery curves of high solid% (T1 and T4) indi-
cate that giving longer Blast Tube residence time improves
the carbon grade approximately by 5%. However, at lower
solid%, the carbon grades are quite similar.
In Figure 4, the effect of Blast Tube volume on met-
allurgical coal flotation is presented. Similar to graphite,
two different Blast Tube volumes were tested at different
pulp solids. Changing the Blast Tube capacity doubled the
residence time. T6 and T9 represent the results at 3.2%
solids and T7 and T10 represent the result at 8.5% solids.
It appears that for both cases, lower volume in Blast Tube
Table 1. Concorde Cell test work operating conditions
Test Number Ore
The Residence Time in
Blast Tube,* %Blast Tube Size†
Pulp Solid%,
by Weight Nozzle Size
Test 1 Graphite 10 1 20 medium
Test 2 Graphite 15 1 5 small
Test 3 Graphite 20 2 5 medium
Test 4 Graphite 20 2 20 medium
Test 5 Graphite 30 2 5 small
Test 6 Metallurgical coal 35 2 3.2 small
Test 7 Metallurgical coal 24 2 8.5 medium
Test 8 Metallurgical coal 12 1 3.2 medium
Test 9 Metallurgical coal 18 1 3.2 small
Test 10 Metallurgical coal 12 1 8.5 medium
*The residence time value is determined by the ratio to shortest residence time in Test 1 and presented in percentage.
† Blast Tube size of 1 and 2 represents the low and high volume, respectively.
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50
Blast Tube residence time, s
T1, 20% solids, BT (1), 8 l/min.
T2, 5% solids, BT (1) ,5.2 l/min.
T4, 20% solids, BT (2), 8 l/min.
T5, 5% solids, BT (2), 5.2 l/min.
68
70
72
74
76
78
80
82
0 10 20 30 40 50 60 70 80 90 100
Carbon Recovery, %
Figure 3. The effect of Blast Tube residence time, by changing the Blast Tube size, – graphite
CarbonRecovery
%
Carbon
Grade,
%
The Effect of Residence Time
In Figure 3, the effect of Blast Tube volume on graphite
flotation kinetics and metallurgical performance is demon-
strated. Throughout the paper, Blast Tube is abbreviated as
BT in graph labels and the number next to it represents
the size of the Blast Tube. T1 and T4 show an impact of
the Blast Tube volume at high solids %whereas T2 and T5
at low solids %.Regardless of pulp solids, it can be clearly
seen from the figures that the flotation kinetics are faster
and the recoveries are higher with the lower volume of Blast
Tube. That means that reducing the residence time in the
Blast Tube leads to faster flotation kinetics. It can be also
deduced that at 20% solids, the effect of Blast Tube volume
is more obvious compared to its effect at 5% solids.
Grade recovery curves of high solid% (T1 and T4) indi-
cate that giving longer Blast Tube residence time improves
the carbon grade approximately by 5%. However, at lower
solid%, the carbon grades are quite similar.
In Figure 4, the effect of Blast Tube volume on met-
allurgical coal flotation is presented. Similar to graphite,
two different Blast Tube volumes were tested at different
pulp solids. Changing the Blast Tube capacity doubled the
residence time. T6 and T9 represent the results at 3.2%
solids and T7 and T10 represent the result at 8.5% solids.
It appears that for both cases, lower volume in Blast Tube
Table 1. Concorde Cell test work operating conditions
Test Number Ore
The Residence Time in
Blast Tube,* %Blast Tube Size†
Pulp Solid%,
by Weight Nozzle Size
Test 1 Graphite 10 1 20 medium
Test 2 Graphite 15 1 5 small
Test 3 Graphite 20 2 5 medium
Test 4 Graphite 20 2 20 medium
Test 5 Graphite 30 2 5 small
Test 6 Metallurgical coal 35 2 3.2 small
Test 7 Metallurgical coal 24 2 8.5 medium
Test 8 Metallurgical coal 12 1 3.2 medium
Test 9 Metallurgical coal 18 1 3.2 small
Test 10 Metallurgical coal 12 1 8.5 medium
*The residence time value is determined by the ratio to shortest residence time in Test 1 and presented in percentage.
† Blast Tube size of 1 and 2 represents the low and high volume, respectively.
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50
Blast Tube residence time, s
T1, 20% solids, BT (1), 8 l/min.
T2, 5% solids, BT (1) ,5.2 l/min.
T4, 20% solids, BT (2), 8 l/min.
T5, 5% solids, BT (2), 5.2 l/min.
68
70
72
74
76
78
80
82
0 10 20 30 40 50 60 70 80 90 100
Carbon Recovery, %
Figure 3. The effect of Blast Tube residence time, by changing the Blast Tube size, – graphite
CarbonRecovery
%
Carbon
Grade,
%