Estudio de modelación termofluidodinámica de proceso de conversión de mata de cobre

1. Thermo-Fluid-Dynamics Modeling for
Continuous Converting Process of Copper
Matte in Packed Bed Reactor: First
Approach
Leandro Voisin and Exequiel Marambio
University of Chile, AMTC

2. Contents
Introduction
State of the art and Problematic
Context and objectives
Computational modeling
Remarks and future work

3. 0
5
10
15
20
25
30
35
40
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
World Production Chilean Production
National Production (CODELCO) Chilean Participation
National Participation (CODELCO)
Cu Content
(kMT)
(%) World
Participation
Year
Introduction
World & Chilean Copper Production & Participation
(kMT Copper Content and % of the World)
(1950 – 2012)
17069
5434
1647
31.8
9.6
83.1%
Pyro
16.9%
Hydro
14179 kMT
China 20.8%
Japan 11.4%
Chile 9.5%

4. Smelter Property Technology
Gas Volume
[Nm3/h]
Chuquicamata CODELCO Flash + CT + CPS 465.000
Altonorte GLENCORE-XSTRATA Noranda + CPS 300.000
Potrerillos CODELCO CT + CPS 80.000
HVL ENAMI CT + CPS 200.000
Ventanas CODELCO Flash + CPS 150.000
Chagres ANGLO AMERICAN CT + CPS 115.000
Caletones CODELCO CT + CPS 260.000
Smelting and Converting in Chile
Introduction
Principal Processes for Extracting Copper from Sulphide Ores

5. Capacity
[Tpd]
Products
[Tpd]
Operation
Time [h]
Gas
[Nm3/h]
T of Gases
[°C]
SO2 in Gas
[%vol]
Operation
under Hood [%]
300~700
Cu2S-FeS
(Matte, White
Metal)
200~600 Blister
250~900 Slag
(2FeO-SiO2, Fe3O4,
{8~12%Cu})
7-10
40.000 –
90.000
550 - 700 8-12 70-80
CPS Converting Stage
State of Art and Problematic
Disadvantages of CPS
• Large size (f x L, inside shell of about 4 x 12m)
• Batch process
• 2 stages are usually required
• High Refractory consumption (about 1 kg/tonne Cu)
Known processes in continuous converting:
Mitsubishi
Kennecott-Outokumpu
Ausmelt C3

6. Continuous Converting ENAMI of
Copper Matte in Packed Bed Reactor
Refractory ladge to
receive liquid matte
Refractory ladge for
distribution of matte
Gas (SO2) + dust
Gas (SO2) + dust
Flux
BURNER BURNER
BURNER
Load measuring cells
Packed bed refratories
(Cr2O3 – MgO [2»f])
TUYERS TUYERS
Air/O2 Air/O2
PACKED BED REACTOR FOR
CONTINUOUS CONVERTING
Slag receptor Blister
receptor
CCE Current Pilot Plant

7. Main advantages
Continuous Converting ENAMI of
Copper Matte in Packed Bed Reactor
• Higher treatment capacity because its geometry and fluid dynamics
[Pilot plant with a capacity to treat 5 tph in one pilot reactor of 1.8 x 1.2 m
(h x f) compared to a 20 tph processed by the current industrial plant.
• Continuous production of blister copper in one steep in comparison to the
batch current process which considers two steeps of slag-forming and
copper-making, respectively.
• Reduction of fugitive gases emissions.(High environmental impact) and
also reduction of refractory consumption.
• Higher converting efficiency and decreasing of process time.

8. Objective:
• Obtain a CTFD model for the continuous
converter in packed bed reactor.
Context and Objectives
Fusion reactor
CCE reactor
Blister Copper
Sampling crucible
Flux feeding
Laboratory plant
• Comsol Multiphysics Software:
– CFD module.
– Heat transfer module.
– Mass transfer module.
 Principal module: CFD
 What to choose?
– Two-Phase immiscible flow modeling,
laminar and turbulent.
– Two-Phase flow modeling in porous
media.
– Two-phase flow modeling with mobile
mesh.

9. Computational Modeling
First model: Desulfurization of copper matte
• Inspired by Díaz’s Thesis [1].
• Focused on mass transfer of
sulfur and Fluid dynamics.
• Only one flow.
• 2D model.
• Simple Geometry.
• Non-animated model.
• Steady state.
New CCE laboratory scale
implementation using COMSOL
Multiphysics

10. • Governing equations:
– The mass transport of sulfur in liquid white metal was modeled with the
general steady state diffusion and convection equation:
𝛻 ∙ −𝐷𝛻𝑐 + 𝑢𝛻𝑐 = 0
– According to Díaz [1] and Fukunaka et al [4], at an operation temperature
of 1473 [K] sulfur reaction kinetics follows a first order law, where the
Robin boundary condition [7] exists for the entire surface made of
chrome-magnesian material:
−𝑛 ∙ −𝐷𝛻𝑐 + 𝑢𝑐 = −𝑘 ∙ 𝑐
– Fluid dynamics was simulated through the incompressible fluid Navier-
Stokes equations at steady state:
ρ 𝑢 ∙ 𝛻 u = 𝛻 ∙ −𝑝𝐼 + 𝜇 𝛻𝑢 + 𝛻𝑢 𝑇
+ 𝐹
𝛻 ∙ 𝑢 = 0
– Díaz [1] found that desulfurization kinetics for a packed bed continuous
converter depends of the oxygen’s fraction in the air injected, taking:
Oxygen % Kinetic constant [𝑠−1
]
21 0.0145
30 0.0155
40 0.0160
Computational Modeling
First model: Desulfurization of copper matte

11. • Governing equations:
– Values are normalized according to Warczok et al [2], following the
equation:
𝑘𝑛 = 𝑘
𝑉𝑚𝑎𝑡𝑡𝑒
𝐴𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛
– The diffusivity of 𝑺𝑶𝟐 in copper was calculated through the Nernst-
Einstein [8] and Wilke-Chang [9] models, whose equations are shown
below:
𝐷𝑎𝑏 =
𝑘𝑇
4𝜋𝜇𝑏𝑅𝑎
𝐷𝑎𝑏 = 7.4 × 10−8
𝜓𝑏𝑀𝑏𝑇
𝜇𝑉
𝑎
0.6
• Solution:
– The finite element tool COMSOL Multiphysics 4.2 was used for carry out
the model’s resolution, generating an appropriate mesh to solve the
model equations with until 20,000 mesh elements depending on
simulation. The calculations were carried out with a i7-3930K processor
with six cores of 3.2 [GHz] and a total memory of 64 [GByte].
Computational Modeling
First model: Desulfurization of copper matte

12.  Fluid dynamics
– Initial condition from rest.
– According to the software, is obtained a
Reynolds number up to 8000 indicating
a mixed regime in some areas.
First arrangement velocity profile for an oxygen concentration of 40% and
Wilke-Chang’s diffusivity model
 Mass transfer
◦ Initial Condition sulfur: 200,000 [ppm]
◦ About 78% of the sulfur removed in the
output Blister.
First arrangement sulfur concentration profile for an oxygen concentration of
40% and Wilke-Chang’s diffusivity model
Computational Modeling Results
First model: Desulfurization of copper matte

13. Mass transfer summary
Diffusivity
model
Diffusivity
[
𝑚2
𝑠
]
Oxygen
%
Final
concentration
of S in Blister
[ppm]
Wilke- Chang 5.14 x 10-9
21 46,744
30 44,538
40 43,521
Nernst-
Einstein
3.14 x 10-9
21 46,776
30 44,593
40 43,503
Computational Modeling Results
First model: Desulfurization of copper matte

14. • All considerations from the first arrangement were maintained.
• Changes the geometry, focused in a square into the packed bed of
10 [cm] x 10 [cm].
• Change the matte area versus reaction perimeter ratio.
• Was solved for the 6 combinations shown in the mass transfer
summary.
Computational Modeling 2nd arrangement
First model: Desulfurization of copper matte

15.  Fluid dynamics
– Initial condition from rest.
– According to the software, is obtained a
low Reynolds number indicating a
laminar regime.
15
Second arrangement velocity profile for an oxygen concentration of 40% and
Nernst-Einstein’s diffusivity model
 Mass transfer
◦ Initial Condition sulfur: 200,000 [ppm]
◦ About 18% of the sulfur removed in the
output Blister.
Second arrangement sulfur concentration profile for an oxygen
concentration of 40% and Nernst-Einstein’s diffusivity model
Computational Modeling Results 2nd arrangement
First model: Desulfurization of copper matte

16. Mass transfer summary
Diffusivity
model
Diffusivity
[
𝑚2
𝑠
]
Oxygen
%
S final
concentratation
[ppm]
Variation rate of
concentration per
cm [ppm/cm]
Wilke-
Chang
5.14 x 10-9
21 161,362 3,863.8
30 165,378 3,462.2
40 165,340 3,466
Nernst-
Einstein
3.14 x 10-9
21 161,962 3,803.8
30 163,707 3,629.3
40 165,952 3,404.8
Computational Modeling Results 2nd arrangement
First model: Desulfurization of copper matte

17. • All fluid dynamic considerations shown before are maintained, but
now in a transient state with 2 immiscible phases.
• The surface tension of copper is added according to Harrison et al
relation [10] at 1473 [K]:
𝜎𝐶𝑢
𝑚𝑁
𝑚
= 1552 ± 35 − (0.176 ± 0.023) ⋅ 𝑇[𝐾°]
• Changes the geometry to a 3D model. Focused on a small
segment into the packed bed.
• Animated model.
• It was solved for 2 situations, using the same equipment
mentioned and a discretized mesh of about 50,000 finite
elements.
Computational Modeling
Second model: Countercurrent fluid dynamic
between copper and air.

18. – Flooded bed with copper at
steady state and air
transferring the flooded bed.
– 5 [s] of simulation.
– According to the software,
speeds reach 2 [m/s], more
than 10 times the initial,
causing areas of mixed
regime.
Time dependent velocity profile for injected air through packed bed with
copper matte. From left to right three vertical sections of the 3D model
and from top to bottom different instants of time (0, 1 and 2 [s]).
Computational Modeling Results
Second model: Countercurrent fluid dynamic
between copper and air.

19. Time dependent velocity profile for injected air through packed bed with
copper matte. From left to right three vertical sections of the 3D model
and from top to bottom different instants of time (3, 4 and 5 [s]).
– Flooded bed with copper at
steady state and air
transferring the flooded bed.
– 5 [s] of simulation.
– According to the software,
speeds reach 2 [m/s], more
than 10 times the initial,
causing areas of mixed
regime.
Computational Modeling Results
Second model: Countercurrent fluid dynamic
between copper and air.

20. • It is possible to notice the direct dependence of the sulfur final
concentration respect to the oxygen concentration present in the
injected air to the reactor.
• The matte area v/s reaction perimeter ratio, changes with respect to the
packed bed arrangement and conditioning the good performance of the
system.
• The 3D model showed must be considered as an approach to the next
step of simulation, the idea is to find the way to make the fluid
dynamics, thermodynamics and mass transport line up under the same
model.
• The model confirms that the CCE technology in packed bed reactor is an
efficient process to desulfurizing copper from smelting stage but still
needs to be studied to fully understand the transport phenomena
involved.
Remarks and future work

21. References
1. J. Díaz, Conversión de Mata de Cobre y Distribución de Impurezas en Lecho Empacado,
Tesis para optar al grado de Magister en Ciencias de la Ingeniería, Mención Metalurgia
Extractiva, Universidad de Chile, 2012.
2. A. Warczok, G. Riveros, T. Marín, G. Wastavino, C. Puga, “Kinetics of Copper Oxidation
and Reduction in Packed Bed Reactors”. Proceeding of The Carlos Diaz symposium on
pyrometallurgy, 2007, Vol. III, pp. 701-714.
3. P. Urzúa, Modelo Físico Predictivo de la Fluidodinámica de Lecho Empacado para
Conversión Continua, Memoria para optar al grado de Ingeniero Civil Químico,
Universidad de Chile, 2008.
4. Y. Fukunaka, K. Nishikawa, H.S. Sohn, Z. Asaki, “Desulfurization Kinetics of Molten
Copper by Gas Bubbling”, Metallurgical Transactions B, Volume 22B, February 1991.
5. W.G. Davenport, M. King, M. Schlesinger, A.K. Biswas, Extractive Metallurgy of Copper,
4th Edition, Elsevier Science Ltd, 2002.
6. Mansilla, Voisin L., “Modeling of the Reduction Stage During the Continous Refining of
Copper in a Packed Bed Reactor”, Universidad de Chile, Advanced Mining Technoloy
Center, 2012.
7. S. Schnittert, R. Winz. E. von Lieres, “Development of a 3D Model for Packed Bed
Liquid Chromatography in Micro-columns”, EMS Third UKSim European Symposium on
Computer Modeling and Simulation, pp 193-197, 2009.
8. E.A. Moelwyn-Hughes, Physical Chemistry, 2nd Edition, corrected printing, Macmill,
New York, 1964.
9. C.R. Wilke, Chem. Eng. Prog., 45, 218-224, 1949; C. R. Wilke and P. Chang, AIChE
Journal, 1, 264-270, 1955.
10. D.A. Harrison, D. Yan, S. Blairs. “The Surface Tension of Liquid Copper”, The Journal of
Chemical Thermodynamics, Volume 9, Issue 12, pp. 1111-1119, December 1977.
11. B. Bird, W. Stewart, E. Lightfoot, Transport Phenomena, 2nd Edition, Chemical
Engineering Department, University of Wisconsin-Madison, 2002.
Thanks for your attention