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Improving metallurgical performance in an industrial flotation bank by upgrading the first cell design
P. Vallejos1, J. Yianatos1, R. Grau2, A. Yáñez2, A. López3 and D. Davoise3
1. Department of Chemical and Environmental Engineering, CASIM, UTFSM, Chile.2. Metso Outotec, Finland.3. Proyecto Riotinto, Atalaya Mining, Spain.
INTRODUCTION
Sharp decrease in feed
mineral grade over time
More complex mineralogy of feed
minerals
Significant increase in cell size
(up to cell of 600 m3)
New Challenges:
• Control strategies
•Operating conditions
• Froth management
• Prediction of results due to changes in mineralogy and/or cell design.
Improvement of metallurgical performance in industrial circuits
METHODOLOGY
Metallurgical performance of a rougher flotation bank by sampling (initial condition).
Metallurgical performance prediction after installing new launders in the first cell (simulation)
Installation of new launders in the first cell.
Metallurgical performance of the bank by sampling, after new launders (simulation validation).
Effect of the new launders on variables that are not commonly obtained from plant surveys (simulation analysis).
METHODOLOGY: Metallurgical sampling Atalaya Mining, Proyecto Riotinto copper concentrator (Spain).
Metallurgical performance characterization of the first cell and the full bank from sampling (shift composites forthree months before and after the launder upgrade, 2018 and 2019).
Sampling before (simulator calibration) and after (simulation validation) the installation of the new launders.
Feed flowrate= 1196 t/h
Cu grade = 0.42 - 0.49%
Solid content of 40 - 41%
Particle size (P80) = 180 - 200 µm.
Atalaya Mining Concentrator
First Cleaner:HG Cells (with wash
water) 2 TC100
3 TC100s (Rougher)
TC300 (beforeupgrade)
TC3
00
tai
ls
METHODOLOGY: Launder design in the first cell
Internal Peripherical Launder
New Launders design
BEFORE AFTER
A new adjustable crowder and center launders were installed to complement the original design to improve bank recovery.
Reduction in the froth surface area and increase in the overflow perimeter, improving the froth recovery.
The gas flowrate had to be reduced after launder upgrade (from 37 to 22.6 m3/h).
METHODOLOGY: Launder design in the first cell
The launder upgrade was carried out during a shut down at the end of July 2018.
Before the launder upgrade After the launder upgrade
TankCell e300:
METHODOLOGY: Industrial flotation simulator
Metallurgical behaviour of
each cell along banks
Operating conditions
Flotation cell design
Feed mineral characteristics
Calculation of each single cell in series: two-zone model
FROTH ZONECOLLECTION ZONE
• Mixing model based on actual RTD
• Feed: Particles, Dij
Size-by-liberation
• Single rate constant kij and Rmax,i,j
• SB as a function of JG (effect on kij)
• 𝑅𝐹 = 𝑓(𝑆𝐹 , 𝜉𝐹 , 𝜏𝐹)
Function of:
Cell design Froth stability Residence time
• Model validation:
Using industrialdata based onfroth recovery
RESULTS: Validation of the simulator prediction
0
10
20
30
40
50
60
30
40
50
60
70
80
90
100
1° cell Final
Co
nce
ntr
ate
gra
de
Cu
, %
Cu
Rec
ov
ery
, %
Measured recoveryPredicted recoveryMeasured gradePredicted grade
Good prediction of the recovery and concentrategrade.
Differences attributed to the measurement error andchemical and mineralogical analysis for simulation.
The simulator allowed for representing the changesin recovery and concentrate grade by modifying thelaunders design in industrial circuits.
RESULTS: Effect of launder upgrade on Cu recovery
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5
Cu
rec
ove
ry (
%)
Cell number
Cum. recovery (before)Cum. Recovery (after)Recovery (before)Recovery (after)
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5C
u r
eco
very
(%
)Cell number
Froth (before)Froth (after)Collection (before)Collection (after)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
0 1 2 3 4 5
Fro
th S
tab
ility
Fac
tor
Cell number
After
Before
Increase in the first cell recovery, but a decrease in the recovery of the next three cells.
However, the final recovery of the bank improved after upgrading the launder design.
Froth recovery increases in the first cell, but decreases in the next cells, mainly because of the decrease in froth stability.
OVERALL EFFECT:
RESULTS: Effect of launder upgrade on Cu recovery
Increase in froth recovery for all particle size classes in the first cell, but mainly for coarse (+150 µm) and intermediateparticles (45-150 µm).
Significant improvement of the final recovery of coarse particles, as well as of middling and locked particles.
0102030405060708090
100
0 1 2 3 4 5
Fro
th r
eco
very
(%
)
Cell number
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5C
u r
eco
very
(%
)Cell number
Coarse (before)Coarse (after)Medium (before)Medium (after)Fine (before)Fine (after)
0102030405060708090
100
0 1 2 3 4 5
Cu
rec
ove
ry (
%)
Cell numberOcclud (before) Occlud (after) Midd (before)
Midd (after) Lib (before) Lib (after)
EFFECT BY SIZE CLASS:
RESULTS: Effect of launder upgrade on conc. grade
0
4
8
12
16
20
24
0 1 2 3 4 5
Co
nce
ntr
ate
grad
e (%
)
Cell number
Coarse (before) Coarse (after)Medium (before) Medium (after)Fine (before) Fine (after)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
0 1 2 3 4 5
Entr
ain
men
t fl
ow
rate
(tp
h)
Cell number
Before
After
Cu grade decreased in the first cell, for the three size classes, but more strongly for coarse particles.
The Cu grade in the next three cells also decreases because of the decrease in the mineral grade fed to these cells.
The concentrate grade of fine particles decreases in the first cell, due to the gangue entrainment.
CONCLUSIONS
• The industrial simulator suitably predicted the metallurgical performance of the rougher flotation bank at ProyectoRiotinto, after modifying the launders design in the first cell.
• The simulation study showed that the launders upgrade in the first cell allowed for a significant increase in the Curecovery, mainly for coarse particles, due to the improvement in froth recovery.
• A significant increase in the final bank recovery was observed, despite the slight negative effect on the Cu recovery inthe next three cells (lower collection and froth recoveries).
• The launder upgrade in the first cell caused a minor decrease in the concentrate grade because of the increase inmineral recovery and in the gangue entrainment. However, the final concentrate grade after launders upgrade wassuitable, considering a rougher stage.
• These results show the important effect that the first cell operation has on the other cells in flotation banks. Thisbecomes relevant when changes are required, focused on optimizing the metallurgical performance.
ACKNOWLEDGEMENTS
Atalaya Mining
Agencia Nacional de Investigación y Desarrollo (ANID), FONDECYT Project Nº 1201335.
Federico Santa Maria Technical University.
Improving metallurgical performance in an industrial flotation bank by upgrading the first cell design
P. Vallejos1, J. Yianatos1, R. Grau2, A. Yáñez2, A. López3 and D. Davoise3
1. Department of Chemical and Environmental Engineering, CASIM, UTFSM, Chile.2. Metso Outotec, Finland.3. Proyecto Riotinto, Atalaya Mining, Spain.