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

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66

68

70

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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