Hydrodynamics of Heap Leaching

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Hydrodynamics of Heap Leaching

• Sylvie C. Bouffard, Ph.D. Candidate
• Prof. David G. Dixon, Supervisor

Biohydrometallurgy Group Metals Materials
Engineering University of British
Columbia 309-6350 Stores Road Vancouver, B.C.,
V6T 1Z4
Seminar 598 Tuesday, October 10, 2000
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Hydrometallurgy A Few Definitions
Oxide Sulfide Ore
Autoclaves
Metal Value
CSTR
Heap
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The Heap Reactor
Heap stacked with agglomerates
Air
Solution
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Agglomeration
The ore particles are agglomerated to improve the
solution flow and to prevent fine plugging.
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The Heap Reactor
Heap stacked with agglomerates
Air
Solution
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A Simple Reactor ? ? ?
Stagnant liquid Mobile liquid
Gas Bacteria
Agglomerates Sulfide Grains
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Refractory Gold Ores
Sulfide Minerals Pyrite Arsenopyrite
Gangue Minerals Quartz Iron oxides
Clays/Mica Carbonates
Precious Metals Gold Silver
Objective Oxidize the sulfide minerals to
liberate the metal values
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Model Development
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Conceptualization
Model 2 Profile-side pore diffusion
Model 1 Mixed-side pore diffusion
Constant pore length
Variable pore length
Mobile
x 0
x X
z 0
Stagnant
u
u
u
Stagnant
z Z
em
em
em
Exp.
es
es
es
kav
Xmax
m
X
Emp.
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Measured Parameters
ef
es
Method
Drainage
Filling
Min Avg Max Literature
2.1 v/v 2.8 3.3 1.7 - 2.5
7 v/v 15.2 23 7 - 13
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Check List
em
/es
MSPD
PSPD - cte
PSPD - var
kav
X
Xmax
m
es
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Numerical Solution
Model equations
Assign values to empirically-fitted parameters
Numerical solution on time and depth Prediction
of Cm at z Z for all times
SSE too large
Least square minimization Calculate SSE for all
Cm(exp)
SSE meets criteria
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Experimental Set-Up
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Does the model make sense ?
Exp.
es
Fitted
7 v/v 15.2 23
10.9 v/v 12.6 17.1
Min Avg Max
10.9 v/v 12.6 17.1
Min Avg Max
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Shape of the Step Curve
Non-ideal
em Z
ta
u
Ideal
ta
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Model Comparison
From the best to the worst fit - PSDP - 3
param - PSPD - 2 param - MSPD - 2 param
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Scale-Up Flow rate
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Scale-Up Height
Data - 0.5 m
Model - X 3.3 cm
Data - 1.6 m
Model - X 4.9 cm
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Effects
Doubling flow
Tripling height
es ta 2X
3X em X ( 2.5 cm)
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Conclusions

• es 5 em (num. and exp.)
• Established the backbone of the numerical
  modeling of any heap operation
• More than adequate fit of the exp. data with a
  two-parameter model
• Scalability of the model with flow and height

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Future Work