Surface tension and dilatational elasticity of various flotation reagents
Author: Antreas FlorentzouSupervisors: Ghislain Bournival, Dr Seher Ata
Key findings/Results
● Froth flotation is the most widely used method for mineral separation and concentration.
● Flotation frothers are used to promote small bubble formation while collectors are employed to increase hydrophobicity of mineralsparticles which facilitates their attachment to air bubbles.
● Surface tension is related to the energy required to increase the surface area of a liquid due to intermolecular forces. In frothflotation process surface tension controls ore separation efficiency because variation of surface tension provides information aboutfrother/collector’s dosage to be used to optimise adsorption time and mineral hydrophobicity (Bournival et al, 2013).
● Dilatational elasticity is another property studied to analyse the interfacial properties of air bubbles and it is the ability of moleculesto preserve surface shape despite area extension.
● Dynamic surface tension decreases as MIBC and 1-pentanol concentration increases, however it remains essentially constant over time at all concentrations of both frothers.
● Dodecylamine affects dynamic surface tension at high concentration. At very low concentrations, no change in surface tension is observed.
● The impact of MIBC and 1-Pentanol on elasticity is insignificant for the concentration range used in the study.
Bournival G, Ata S, Karakashev S, Jameson G 2013, ’An investigation of bubble coalescence and post‐rupture oscillation in non‐ionic surfactant solutions using high‐speed cinematography’, Journal of Colloid and Interface Science, vol . 414, pp. 50‐58
SINTERFACE 2011, ‘The physical principle’, Profile Analysis Tensionmeter PAT 1‐M, Manual‐pdf, vol.5, pp. 9‐10
● A tension-meter (PAT-1M) device is used to measure surface tension of twofrothers and a collector commonly used in flotation technology (SINTERFACE2011) .● Elasticity of the reagents for various concentrations are also measured using thesame instrument.
● Reagents used in the study: Dodecylamine (DDA); 1-Pentanol; Methyl isobutylcarbinol (MIBC).
Background
Aim Methodology
Key Findings/Results
Concluding Remarks References
Figure 2: Dynamic surface tension for various concentrations of MIBC
Figure 3: Dynamic surface tension for various concentrations of 1‐Pentanol
Figure 4: Dynamic surface tension for various dodecylamineconcentrations
Figure 5: Equilibrium surface tension for various dodecylamineconcentrations
Figure 6: Comparison of equilibrium surface tension for various concentrations of MIBC and 1‐Pentanol
Figure 7: Harmonic perturbations at concentration of M dodecylamine
Investigate the behaviour of surface tension and dilatational elasticity for various flotation reagents
Dynamic surface tension decreases as the concentration of MIBC and 1‐pentanol increases , however it remains constant over time.
Dodecylamine affects dynamic surface tension at high concentration. At very low concentrations
surface tension remains constant.
Equilibrium surface tension decreases with an increase in concentration for the three reagents tested. At high concentrations, MIBC is more effective lowering surface tension than 1‐Pentanol as shown by the adsorption constant (KL).
Example of Fourier analysis on DDA measurements used to determine the elasticity of the interface. Change in
concentration of MIBC and 1‐Pentanol showed insignificant effect on elasticity over the frequency range of 0.01 to 0.2 Hz.
Figure 1: PAT 1‐M tension‐meter device is illustrated on the top figure while output of SINTERFACE program is shown on the bottom figure (SINTERFACE
2011)
Emerging bubble
50
52
54
56
58
60
62
64
66
68
70
72
74
0 20 40 60 80 100 120
Dynam
ic surface tension ( m
N/m
)
Time (s)
0.004 M 0.002 M 0.001 M 0.0004 M
0.0002 M 0.02 M 0.01 M
50
52
54
56
58
60
62
64
66
68
70
72
74
0 20 40 60 80 100 120
Dynam
ic surface tension (mN/m
)
Time (s)
0.02 M 0.01 M 0.002 M 0.001 M
0.0004 M 0.0002 M 0.004 M
30
35
40
45
50
55
60
65
70
75
80
0 500 1000 1500 2000 2500 3000
Dynam
ic surface tension (mN/m
)
Time(s)
0.00006 M 0.00004 M 0.00002 M 0.00001 M
0.000004 M 0.000002 M 0.000006 M
Pump control
Emerged bubble
30
35
40
45
50
55
60
65
70
75
1.00E‐06 1.00E‐05 1.00E‐04
Equilibrium Surface tension (mN/m
)
Concentration (M)
45
50
55
60
65
70
75
1.0E‐05 1.0E‐04 1.0E‐03 1.0E‐02 1.0E‐01
Equilibrium surface tension (mN/m
)
Concentration (M)
MIBC 1‐Pentanol
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