performance characterisation of news frothers for sulphide mineral flotation
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Performance Characterization of New Frothers for Sulphide Mineral FlotationCape Town, 14th November 2017
D. ChipfunhuG. BournivalS. DickieS. Ata
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For flotation to take place, 3 individual consecutive sub-processes have to take place in collection zone:
1. Collision (Ec) – Bulk hydrodynamics and kinetics, frothers affect collisionefficiency (bubble size, bubble rise velocity, flotation rate)
2. Adhesion or Attachment (Ea) – thermodynamics, surface forces, collectorsaffect attachment efficiency. But frothers may affect induction time
3. Stability (Es) – hydrodynamics and thermodynamics, disruptive forces, particlesize and specific gravity
4. Froth recovery factor – froth stability
Frothers are critical for all the sub-processes and froth recovery
Frothers in flotation
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Frother characterization
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Performance characterization of frothers mainly:
Bubble size (CCC) and other hydrodynamic characteristics
Froth/Foam stability (foaminess)
Water carrying capacity
These do not correlate well with flotation performance
We propose to use further fundamental parameters to characterize frothers
Coalescence times
Damping of bubble surface oscillation after coalescence
Detachment of particles after coalescence and correlate to flotation performance
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Materials and Methods
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In this work we have evaluated frother performance through two phase systems:
Foaminess (dynamic foam stability) in foam column
Bubble size and critical coalescence concentrations
Coalescence times and damping constant
Three phase liquid-gas-solid system
Particle detachment after coalescence (two phase)
Flotation test work
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Materials and Methods
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Quartz and chalcopyrite mixture ~3% Cu used for flotation test work. Chalcopyrite was
aged in under room temperature for six months. Flotation carried out in Denver cell,
30% pulp density, pH 9 with no collector
Three frother formulations from BASF were compared against MIBC and TPM
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Foam column – Foam volume
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5ppm (●); 10ppm (■); 20ppm (♦); 50ppm
(▲); 100ppm (x).
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Foam column - Foaminess
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MIBC (♦), TPM (■), BASF’s frother 1 (▲), BASF’s frother 2 (●) and BASF’s frother 3 (x). A - 5ppm; B - 10ppm; C - 20ppm; D -50ppm and E - 100ppm
Σ = 𝐻𝐻𝑚𝑚𝑚𝑚𝑚𝑚𝐴𝐴𝑄𝑄
; Σ is foaminess, Hmax
is maximum equilibrium foam
height, A is foam column cross
sectional area and Q is the
volumetric air flow rate
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Flotation – Recovery Time Profiles
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BASF’s frothers give higher recovery compared to MIBC and TPM
BASF’s frothers provide better dose efficiency and recovery
MIBC (♦), TPM (■), BASF’s frother 1 (▲), BASF’s frother 2 (●) and BASF’s frother 3 (x).
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Flotation – Grade versus Recovery
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BASF’s frothers provide higher recovery and grade compared to MIBC for all frother concentrations investigated
MIBC (♦), TPM (■), BASF’s frother 1 (▲), BASF’s frother 2 (●) and BASF’s frother 3 (x).
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Coalescence times and damping constant
Increased bubble stability compared to MIBC and tripropyleneglycol methylether (TPM)
Improved bubble stability – lower oscillation than MIBC and TPM
MIBC (♦), TPM (■), BASF’s frother 1 (▲), BASF’s frother 2 (●) and BASF’s frother 3 (x).
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Particles detachment
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00,20,40,60,8
1
0 10 20 30Det
achm
ent (
1-R
)
Concentration of frother, ppm (v/v)
Less particles detach from the bubble after coalescence event for BASF frother 1, 2 and 3 compared to MIBC and tripropyleneglycol methylether (TPM)
Particles detachment decreases with increasing frother concentrations
MIBC (♦), TPM (■), BASF’s frother 1 (▲), BASF’s frother 2 (●) and BASF’s frother 3 (x).
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Conclusions
Two phase parameters such as foaminess and froth stability are poor predictors of flotation performance
We have formulated frothers that give improved flotation performance. BASF frother formulations produced improved flotation recovery and grade.
We have characterised our frothers and explained flotation recovery based on fundamental parameters of coalescence times, damping constant and particle detachment after coalescence
Empirical approach produced high performing frothers
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INTERNAL