Frother type Impact over size by size Cu recovery

Impact of Hydrodynamic Conditions
and Frother Strength over Coarse
and Fine Particle Flotation
Juan Anes, Technology Director Flottec, Canada
Rob Thorpe, President Metrix Plant Technologies, Canada
Frank Cappuccitti, President Flottec LLC, USA

• Introduction and Background
• Laboratory Test Work Objectives
• Test Conditions and Methodology
• Metallurgical Results and Trends
• Conclusions
Overview

3
GROUP OF ASSOCIATED COMPANIES
Mexico
Chile
LLCAFRICAAUSTRALIA

• Chemiqa and Metrix are part of the group of Flottec LLC
associated companies
• Metrix Plant Technologies is a new corporation looking to offer
full flotation optimization services.
• Research was required to add further advanced flotation
technologies to their toolbox, such as understanding the
implications of new hydrodynamic knowledge.
• A self funded program was set up to investigate the impact of
changing Bubble Size Distribution (BSD) and frother strength on
size by size recovery
Introduction

• Contradicting theories about how particles interact with bubbles in a
flotation machine: Flotation Kinetic Theory vs Bubble Film Properties
– Hypothesis for FKT :
• Large and small bubbles may affect recovery of coarse and fines ore particles
differently
– Hypothesis for BFP:
• The properties of the bound water film around bubbles impact coarse and fine
particles recovery
• Fact: Bubble size distribution changes as frother concentration changes
• Flottec Ongoing Learning activities:
– Hydrodynamic Curve of Frothers and its applicability to normal operation
conditions
Background

Bubble/Particle Interaction
Does the relative size of the bubble to the
particle affect collision probability?
Does the bound water layer properties affect
the probability of attachment and detachment?

Bubble/Particle Interaction
Attaches - Detaches
Goes through
Attaches

J.A. Finch , S. Gelinas and P. Moyo; Minerals Engineering, Volume 19, Issues 6-8, May-July 2006, Pages 726-733.
An interpretation of the physical idea of bound water layer based on InfraRed results.
(a) Bubble in air, (b) bubble in water.
Bubble Thickness

D32 & BSD* Change with Frother Addition
0
1
2
3
4
5
0 5 10 15 20 25 30
FROTHER ADDITION (ppm)
D32(mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
FREQUENCYDISTRIBUTION
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
25
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
50
0.1 1.0 10.0
Db (mm)
0
1
2
3
4
5
0 5 10 15 20 25 30
D32(mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
25
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
50
0.1 1.0 10.0
Db (mm)
0
1
2
3
4
5
0 5 10 15 20 25 30
D32(mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
25
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
50
0.1 1.0 10.0
Db (mm)
0
1
2
3
4
5
0 5 10 15 20 25 30
D32(mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
0.1 1.0 10.0
Db (mm)
0
5
10
15
20
25
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
0.1 1.0 10.0
Db (mm)
0
10
20
30
40
50
0.1 1.0 10.0
Db (mm)
2 mm
Constant Jg = 0.5 cm/s
* Bubble Size Distribution

• Identify changes in the kinetic flotation behaviour of different sized particles(+212µm,
+106µm, +53µm, -53µm) by manipulating hydrodynamic conditions (Jg and CCx)
• Identify the effects of :
• Bubble size, Di
• Bubble surface area flux, Sb
• Infer the effect of Bound water layer thickness and frother strength
Laboratory Test Work Objectives

Laboratory Test Conditions & Methodology
F150 chosen as strong frother to provide thick filmed bubbles (450 mw PPGE)
F160-09 chosen as weak frother to provide thin filmed bubbles (200 mw PPGE)
F150 : CCC95 = 3.75 ppm @ 0.5 Jg and 5.25 ppm @ 1.0 Jg
F 160-09 : CCC95= 12.0 ppm @ 0.5 Jg and 18 @ 1.0 Jg

• 20 samples – 10 kilos each - were staged crushed to 100% passing 1.7 mm to avoid fines generation.
• The ore was ground at 60% solids in a laboratory mill. The average results of the grinding stage reached
an average P80 of 227 microns, with a narrow standard deviation of 2.8 microns, or a relative standard
deviation of 1.2%.
• Particle size distribution of the ground ore and size by size chemical assay fractions, for Cu and Fe,
were executed for the 20 samples.
• Each 10 kilos sample was subjected to kinetic flotation test in a 28 litres flotation cell at 29% solids,
adding 300 g/ton of lime to reach pH 10.
• The flotation collector added was Sodium Isopropyl Xanthate (SIPX), added at a dosage of 7 g/t.
• The kinetic tests were developed to obtain 4 concentrates, removed after 1 minute, 3 minutes, 7
minutes and 15 minutes for a total flotation time of 26 minutes.
• The breakdown of test conditions is shown in Table 1. The tests were divided into 4 families each of 4
tests, as grouped by frother type (F150 and F160-09) and Jg (0.5 and 1.0).
• Within each of the 4 families the CCCX value (dosage relative to the CCC value) was varied in order to
change Db and Sb.
• The program contained 2 conditions that were run as triplicates in order to measure repeatability.

4 families of tests /Copper porphyry (chalcopyrite)
Gas Rate – Jg = 0.5 and 1.0 cm/s
Test
Number
Test
Sequence
Grind P80 (Back
calc) Jg
Frother
Type
Dosage
(CCCX)
Frother
ppm D32 Sb
1 3 221.8 1 F150 66 1.48 3.52 17.05
4 11 227.9 1 F150 85 2.61 2.93 20.46
5 20 227.8 1 F150 95 4.12 2.56 23.43
6** 2 221.6 1 F150 100 9.49 2.03 29.55
9 4 226.4 0.5 F150 30 0.73 3.51 8.55
10 1 226.1 0.5 F150 52 1.50 3.01 9.97
11 9 225.2 0.5 F150 69 2.39 2.53 11.88
12 14 225.7 0.5 F150 89 4.50 2.04 14.70
13 17 229.4 1 F160-09 66 3.65 3.12 19.24
14 13 226.8 1 F160-09 85 6.41 2.63 22.86
15 10 227.5 1 F160-09 95 10.12 2.01 29.88
16 7 223.3 1 F160-09 100 23.34 1.23 48.73
17* 5 226.0 0.5 F160-09 30 1.79 3.41 8.79
18 6 233.1 0.5 F160-09 52 3.68 2.81 10.66
19 19 229.6 0.5 F160-09 69 5.88 2.10 14.30
20 12 225.6 0.5 F160-09 89 11.07 1.47 20.36
* triplicate series 1
** triplicate series 2

Test
Number
Test
Sequence
Grind P80 (Back
calc) Jg
Frother
Type
Dosage
(CCCX)
Frother
ppm D32 Sb
1 3 221.8 1 F150 66 1.48 3.52 17.05
2* 8 224.3 0.5 F160-09 30 1.79 3.57 8.40
3* 18 227.3 0.5 F160-09 30 1.79 3.30 9.08
4 11 227.9 1 F150 85 2.61 2.93 20.46
5 20 227.8 1 F150 95 4.12 2.56 23.43
6** 2 221.6 1 F150 100 9.49 2.03 29.55
7** 16 230.8 1 F150 100 9.49 1.76 34.09
8** 15 226.2 1 F150 100 9.49 1.57 38.17
9 4 226.4 0.5 F150 30 0.73 3.51 8.55
10 1 226.1 0.5 F150 52 1.50 3.01 9.97
11 9 225.2 0.5 F150 69 2.39 2.53 11.88
12 14 225.7 0.5 F150 89 4.50 2.04 14.70
13 17 229.4 1 F160-09 66 3.65 3.12 19.24
14 13 226.8 1 F160-09 85 6.41 2.63 22.86
15 10 227.5 1 F160-09 95 10.12 2.01 29.88
16 7 223.3 1 F160-09 100 23.34 1.23 48.73
17* 5 226.0 0.5 F160-09 30 1.79 3.41 8.79
18 6 233.1 0.5 F160-09 52 3.68 2.81 10.66
19 19 229.6 0.5 F160-09 69 5.88 2.10 14.30
20 12 225.6 0.5 F160-09 89 11.07 1.47 20.36
* triplicate series 1
** triplicate series 2

Metallurgical Results & Trends

(+212µm Size Fraction – Cu recovery)

Metallurgical Results & Trends (+212µm size Fraction)
• Final recoveries for this size fraction fit into strong linear trends for all 4 families of tests
• For all of the 4 conditions of Jg and frother selection, final recovery increases with decreasing
bubble size.
• All curves appears to converge at a common maximum recovery, where minerals liberation caps
the highest recovery attainable in this size fraction.
• At higher Db values (due to low CCCx frother dosage) recovery drops. This is much more
pronounced for the weak F160-09 frother than for the stronger F 150 (of course!!)
• Our hypothesis is that this happens due to the beneficial effect of the thicker bound layer of
water associated to F150 on coarse particle collection

•There is no clear trend for recovery of averaged size particles.
•This is usually the size fraction that floats very well in all the plants and at laboratory level.
•It has a high affinity for any bubble type

(-53µm Size Fraction – Cu recovery)

(-53µm Recovery Size Fraction – Cu recovery)

• Cell hydrodynamic parameters show significant influence on flotation performance
• All the size fractions had better recoveries at the smallest bubble size.
• It can then be implied that matching bubble size distribution (large bubble for large
particles, etc.) does not appear to optimize recovery. This implies that the frother
should be added at the CCC for maximum recovery.
• As bubble size reaches similar values when frother is added at its CCC concentration,
then it can be inferred that Bubble film properties have an impact on Cu Recovery,
especially on fine particle flotation (thin layers give higher recovery).
• Weaker frothers do seem to promote fine particle flotation and stronger frothers would
promote coarse material recovery
• Flotation of coarse particles requires less flotation time while more flotation time is
required as particles get finer.
• Coarse particles recovery appears to be inversely correlated to bubble size but may not
have a strong dependency on Sb
• Fine particles recovery seems to be driven by higher Sb values
• Intermediate size (+53 microns) has little sensitivity to frother and bubble size. This size
can be considered the sweet spot for flotation.
Conclusions

• As per operational experience these relationships also hold at plant level.
• Operations personnel should strive to apply these principles and try to come up with mix
frother strategies.
• It s suggested to have the CCC point for each frother in mind as a starting point to dose the
correct amount of frother (to ensure minimum bubble size)
• A mix frother strategy is made up of weak and strong frother mixed up at different ratios. This
mix can be either alcohols and glycols or alcohols and glycols together.
• Special care must be exercised for operations with high circulating loads as even alcohols can
recirculate back to increase frother well above the CCC point in any flotation stage. This issue
will cause over frothing, high froth stability and slurry overflowing out of flotation cells.
• Strategies to deal with coarse and ultrafine particles in the plant would involve Careful frother
Selection. Frother type and dosage has a major impact on flotation performance.
• The wrong frother selection may lead to not collecting liberated particles. Frother selection
and hydrodynamics concepts must be in every ore processor tool box.
Plant Implications (From Flottec Experience)

• Plant Personnel and Metallurgists must factor CCC, frother policy and froth stability caused by
ore particles. This aspects will be a special situation for every plant.
• The effects of using sea water for flotation must be understood, as well frother present in
circulating loads.
• Jg needs to be controlled in a plant, specially when it has different flotation cell sizes.
• Metallurgist, Operations Personnel and Senior Manager must think about frothers as the
component that can make the whole operation fail or underperform.
• Frothers are the component that makes up the conveyor belt that removes valuable minerals
out of the flotation machine. Without this conveyor made up of bubbles all the valuables may
end up in the tailings pond.
• Frother and reagent selection is not a magic bullet. Despite having the correct flotation
reagents, the role of
– operational knowledge - maintenance aspects - flotation machine type
• have an important role to play and this role must be understood. There is no option here.
Plant Implications (From Flottec Experience)

We would like to thank McGill University for their assistance,
especially Professor Finch.
We would also like to thank Jan Nesset for his contributions to the
program.
And many thanks to all the people at Metrix, BlueCoast, Chemiqa
and Flottec who funded and performed the work.
Acknowledgements

QUESTIONS?
PREGUNTAS?
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Frother type Impact over size by size Cu recovery

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