scale up of hydrodynamic and metallurgical response in ... · scale up of hydrodynamic and...
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Scale Up of Hydrodynamic and Metallurgical Response in HeapLeaching OperationsJorge M. Menacho, De Re Metallica Ingeniería SpA, DRM Tech, Avda. del Valle 576, Huechuraba, Santiago, Chile
Contents
• Current Scale Up Criteria
• The Proposal
• Final Remarks
Conventional Scale Up CriteriaCase 1: Leach Ratio (LR)
The LR hypothesis should be always verified before applying it. Experiments atdifferent irrigation rates give the information to check this correlation. Thiscriteria is not directly deduced from the conventional kinetics formulations.
j ji iji
Ap Ap
1 2
q Δtq Δt
=ρ z ρ z
(3)
Case 2: Leach Time
Again, this criteria must be verified before applying it. Same experiments above-described allow to set the correlation degree between Extraction and Time.
(4)
j j ji i iji
i i j ji j1 2
q A Δtq A Δt
=q A q A
Other Related Scale Up CriteriaCase 3: Passed Acid
Same acid curing dosage is assumed the same at both scales. This criteria appliesbetter when the LR applies
(5)
Case 4: Consumed Acid
Here time affects the result; it applies better when t this the controlling variable.
(6)
A j j jAi i iji
Ap Ap
1 2
c q Δtc q Δt
=ρ z ρ z
M1 E M2E = f E
In all cases both maximum extractions are assumed directly proportional, that is:
(7)
A j j jAi i iji
Ap Ap
1 2
c q Δtc q Δt
=ρ z ρ z
Conventional Scale Up Criteria
DESIGN
DESIGN
Clearly, something is wrong with this method…
DESIGN
DESIGN
Parameter Column HeapHeight, m 1 5q, L/h/m2 7 4LR, m3/t 5.5 2.37Time, days 40 197
Parameter Column HeapHeight, m 1, 4 y 6 5q, L/h/m2 5 y 10 4LR, m3/t 4 a 16 2.37Time, days 90 197
What else can we do?
Quid Ultra Faciam?
S1 S SM
dc= -k c c
dt
Menacho (1998) suggested 2 (main) controlling leaching steps:
S2 S SM
dc q= -k c c
dt z
qt
ρz
S S0c t = c for t = 0
S SMc t = c for t
M 1 2
qE t = E 1 - exp - k + k t
ρz
Chemical Control
Convective Control; with Leach Ratio (LR)
Both phenomena occur in parallel; B.C. are as follows:
Assuming plug flow condition an integrated expression is obtained, widelyvalidated by DRM in most of the industrial heap/dump leach Chilean operations:
DRM Leach Kinetics
(8)
(9)
(10)
(11)
(12)
In this case k1 << k2 q/(z), that is:
M 2
qE t = E 1 - exp - k t
ρz
Limiting CasesCase 1: High solubility and fast kinetics (classical oxide ores)
The extraction is controlled by the leach ratio (LR), then:
M 2E t = E 1 - exp -k LR
In this case k1 >> k2 q/(z), then: M 1E t = E 1 - exp - k t
Case 2: Low solubility and slow kinetics (sulphide and refractory oxide ores)
Now the extraction yield is controlled by the leach time (t).
In this formulation EM, k1 and k2 are pseudo-kinetic parameters as they arefunction of operational conditions.
(13)
(14)
(15)
1 2
M1 1 2 1 E M2 1 2 2
1 1 2 2
q qE 1 - exp - k k t f E 1 - exp - k + k t
ρ z ρ z
General Scale Up CriteriaCase 3: Mixed Chemical/Convective Control (Most of Real Situations)
(16)
The following equality must be satisfied to get similar Extraction at scales 1 and 2:
A sufficient condition to satisfy Eq. 16 is given by:
M1 E M2E f E
2 1 1 2 2 2
1 1 2 2
k q t k q t
ρ z ρ z
1 1 2 2
1 1 2 2
q t q t
ρ z ρ z
1 1 1 2k t k t 1 2t t
E M1 M2f E E
1 1
1 2
2 2
zq q
z
(17)
(18)
Accordingly, same extraction is got if we run a 10 m column at 10 L/h/m2 and 1 mcolumn at 1 L/h/m2, keeping time and other conditions the same. P. Mayta et al.(2015) were the first applying this concept in the Sierra Gorda Leach Project.
Case I: Reduced Flow Scaling Criteria
A key aspect for success is the strictapplication of the protocol for: (i) Samplepreparation, especially for drilling coretesting, (ii) Agglomeration, (iii) Columnloading and (iv) Irrigation calendar, includingthe hydrodynamic wetting ramp.
Results here shown come from tests designedby DRM and executed by ASMIN S.A.
Case I: Reduced Flow Scaling Criteria
Case II: Reduced Flow Scaling Criteria
Case II: Reduced Flow Scaling Criteria
In Summary…
1m
4m 4m
HYDRODYNAMICS
REDUCED FLOW UNITARY TEST
• …GOOD NEWS, but still a task is PENDING: How these resultsare scaled up to real Heap/Dump Operation in a reliable way?
Hydrodynamics is the Key aspect
The New Way to Run Small-Scale Leach Tests
• The Reduced Flow Unitary Test is disruptive in terms ofconceptual support, simplicity, cost and reliability of results…
• We strongly believe this soon will be the new way to run leachtests everywhere…
Reflexions…
Flow Pattern Scale Up
OBSERVATION:
Flow is constrained by
the column wall thus
changing the flow pattern
and also the copper
extraction kinetics, driving
to a FLAT liquid front, that
is a flow pattern close to
PLUG FLOW condition.
A A
ij iz
i i
hK K K
x
t x
iij s
i j i
c s c q cD s
t t x x x
Solution to the Navier-Stokes Equations in a bidimensional field:
Solute transport – Convectionand dispersion equation
Liquid flow – Richards equation
Boundary conditions:
- First type or Dirichlet type- Second type or Neumann type- Third type or Cauchy type
Time
RT
D, T
ime
-1
COLUMN
HEAP
Flow Pattern is a Major Dissimilitude…
A Phenomenological Model is Appropriate to Solve this Problem
System of Integral Equations (Menacho, 1999)
* * *
Column i Column PF i0R p ,t = φ t R p ,t, t dt
PF i PF j
R p ,t R p ,t
* * *
Pad j Pad PF j0R p ,t = φ t R p ,t, t dt
(19)
(20)
(21)
Hydrodynamic andMetallurgical Heap Leach Model
Variable-saturation liquid infiltration throughout a porous beds is described by theRichards´ equation (Continuity and Momentum equations). In one dimension it is,
θ h= k h + 1
t z z
Where θ is the saturation, k is the hydraulic conductivity, h is the matric potential,z is the height coordinate and t is the time. Boundary conditions are as follows:
0 0
z=0
hθ z,0 = θ and k h + 1 = q 0,t
z
The dynamic liquid inventory inside the heap and the effluent flowrate are themain responses of the model. Relations {h / / k} are needed to solve theRichards equation
L.A. Richards (1931), "Capillary Conduction of Liquids through Porous Mediums“, Physics, 1(5): 318- 333.J.M. Menacho and F.J. Troncoso (2013), “Scale Up of Heap and Dump Leaching Results”, COPPER 2013.
(22)
(23)
Matric or Characteristic SWCC Curve (h vs. Relationship)
Range accordingto hydrodynamicquality or the ores
Liq
uid
Co
nte
nt
, %
v/v
CV
CV
CV
Soil Suction h, kPa
Non-Saturated PermeabilityCurve ( vs. k Relationship)
Increase in Physical Quality
Usual Heap Leaching Operating Region
Saturated HydraulicConductivity
Hyd
rau
licC
on
du
ctiv
ity
k, m
/s
Liquid Content , % v/v
Volume of the LiquidLiquid Content =
Volume of the Heap
LIX-SX-EW Dynamic Simulator
SX/EW
RaffinatePLS
Aeration
MINE PLAN
BLASTINGCRUSHINGAGGLOMERATION
Copper Cathodes
...
Stacking DischargeDrainage
Wetting Irrigation Washing
DRM Simulator
Block Diagram of the DRM.BioLeach® Simulator.
Multi-Layer Dump Leach Simulator
Subsequent leach in the lower layers supplies additional Copper dissolution.Exposed area per unit mass is reduced as the dump grows. At the same time,inner temperatura increases and hydrodynamics and kinetics change.
L a y e r 1
L a y e r 2
L a y e r 3
L a y e r 4
U n d e r i r r i g a t i o n
N o i r r i g a t i o n
I r r i g a t i o n r a t e qL 1
A e r a t i o n r a t e qA 1
[ C o m p o s i t i o n ]1
T e m p e r a t u r e 1
I r r i g a t i o n r a t e qL 2
A e r a t i o n r a t e qA 2
[ C o m p o s i t i o n ]2
T e m p e r a t u r e 2
I r r i g a t i o n r a t e qL 3
A e r a t i o n r a t e qA 3
[ C o m p o s i t i o n ]3
T e m p e r a t u r e 3
C o m p o s i t i o n - 1
T e m p e r a t u r e - 1
C o m p o s i t i o n - 2
T e m p e r a t u r e - 2
. . .
L a y e r 1
L a y e r 2
L a y e r 3
L a y e r 4
U n d e r i r r i g a t i o n
N o i r r i g a t i o n
I r r i g a t i o n r a t e qL 1
A e r a t i o n r a t e qA 1
[ C o m p o s i t i o n ]1
T e m p e r a t u r e 1
I r r i g a t i o n r a t e qL 2
A e r a t i o n r a t e qA 2
[ C o m p o s i t i o n ]2
T e m p e r a t u r e 2
I r r i g a t i o n r a t e qL 3
A e r a t i o n r a t e qA 3
[ C o m p o s i t i o n ]3
T e m p e r a t u r e 3
C o m p o s i t i o n - 1
T e m p e r a t u r e - 1
C o m p o s i t i o n - 2
T e m p e r a t u r e - 2
. . .
Multiple-Floor 3D DRM Dynamic Dump Leach Simulator®.
Performance of the DRMHydro-Met Heap Leach Simulator
• A correct scale up procedure mustinclude both the hydrodynamics and themetallurgical mechanisms
• A phenomenological model is the besttool to project results from small columnto industrial heap/dump operations
PLS Flowrate
Cu Concentration in PLS
Cu Production
Hydrodynamic Saturation Profiles:Geotechnical Constrains
Safety Limit
Clayish Ore
Competent Ore
The physical ore quality is
detected in the Unitary
Leach Test and it is scaled
by hydrodynamics
Solution Channeling, Ponding and Landscapes
Safe and EfficientLeach Operation
Volume of the Liquid in the HeapSaturation =
Volume of the Heap Porosity
NO FIT OF DATA; PREDICTION FROM 1 m/1 ton crib TO 18 m, 7 millions tons pad
Notable Study Case: 100% PredictionCop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 1PAD 02
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 03
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 04
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 05
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 06
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 07
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 08
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 09
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
PAD 10
Cop
per
Extr
acti
on, %
Time, days
Industrial Pad Scaled from Mini Crib
DRM.BIOLEACH MODEL
Final Remarks
Conceptual frame for correct scale up and improvedmethodology to perform hydrometallurgical column testing hasbeen given
The UNITARY COLUMN properly used is much powerful thanwe think…especially when sample availability is scarce
Scale up involves not only metallurgical aspects but alsohydrodynamics, often neglected by the Metallurgists
Liquid infiltration through variable saturation porous mediaprovides the right frame to scale up and predict industrialheap/dump leaching results in a safe way
To getthe right
results…
Use the right tools…
In theright
way…
Jorge M. Menacho, De Re Metallica Ingeniería SpA, DRM Tech, Avda. Del Valle 576, Huechuraba, Santiago, Chile, HydroProcess 2017, Gecamin, June 21 – 23, Santiago - Chile