disclaimer - metaleach
TRANSCRIPT
![Page 1: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/1.jpg)
![Page 2: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/2.jpg)
Disclaimer
THIS DOCUMENT IS BEING SUPPLIED TO YOU SOLELY FOR YOUR INFORMATION AND MAY NOT BE REPRODUCED, FURTHER DISTRIBUTED TO ANY OTHER PERSON OR PUBLISHED, IN WHOLE OR IN PART, FOR ANY PURPOSE.
This document is being communicated in the United Kingdom only to (a) persons who have professional experience in matters relating to investments falling within Article 19(1) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2001 (the “Order”) or (b) High Net Worth Entities within Article 49(2) of the Order (all such persons being referred to as “relevant persons”). This document is only directed at relevant persons, and any investment or investment activity to which this presentation relates is only available to relevant persons or will be engaged in only with relevant persons. Solicitations resulting from this document will only be responded to if the person concerned is a relevant person. Other persons should not act upon this document or any of its contents. The distribution of this document in other jurisdictions may be restricted by law, and persons into whose possession this document comes should inform themselves about, and observe, any such restrictions. The information in this document, is subject to updating, completion and revision, further verification and amendment. No representation is made byAlexander Mining plc or any of their principals, advisers, representatives, agents, officers, directors or employees as to, and no responsibility, warranty or liability is accepted for, the accuracy, reliability, or reasonableness or completeness of the contents in this document. No responsibility is accepted by any of them for any errors, mis-statements in, or omissions from, this document,nor for any direct or consequential loss howsoever arising from any use of, or reliance on, this document or otherwise in connection with it. The information in this document is confidential and must not be copied, reproduced or distributed to others at any time. This document does not constitute an invitation to buy shares in Alexander Mining plc.
This document is not an offer of securities for sale in the United States of America. Securities may not be offered or sold in the United States of America absent registration or an exemption from registration. Safe Harbour statement: this document may contain forward-looking statements that reflect the Company's current expectations regarding future events, including the development of the Company's projects, as well as the Company's working capital requirements and future capital raising activities. Forward-looking statements involve risks and uncertainties. Actual events could differ materially from those projected herein and depend on a number of factors, including the success of the Company's development strategies, and the successful and timely completion of clinical studies, the ability of the Company to obtain additional financing for its operations and the market conditions affecting the availability and terms of such financing.
![Page 3: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/3.jpg)
MetaLeach Limited is formed to commercialise proprietary new
mineral processing technologies with the potential to revolutionise
the extraction processes for many base metal deposits.
MetaLeach Ltd. owns the intellectual property to two
hydrometallurgical technologies where provisional patents have
been filed, namely AmmLeach® and HyperLeach™.
![Page 4: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/4.jpg)
![Page 5: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/5.jpg)
Key features
• no special equipment required
• high selectivity for target metals
• ambient temperature and pressure
• minimal decommissioning costs
• small SX plant size for production
![Page 6: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/6.jpg)
electrowinning
CuH2SO4
stripping
heap leach
cure solution
cathodes
H2O
CO2
crud removal
carbonate ppt
CaO
CaCO3
LIX-84i in kerosene
loading
silver recovery
NH3 wash
bleed impurities
CaCO3(NH4)2CO3
NH3
R2Cu R2Cu
R
Cu
NH3
NH3
RNH4
NH3
Leon flowsheet
![Page 7: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/7.jpg)
Main features
![Page 8: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/8.jpg)
cure stage• tailored to ore
– oxidising agent
– reducing agent
– complexing agent
• low volume– 80% of pore volume
• high concentration– low cost as low volume
![Page 9: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/9.jpg)
leach stage• complexing agent
– ammonia
• complexes with Cu, Zn, Ni, Co, Mo, etc
– Cu(NH3)42+, Zn(NH3)4
2+ etc
• doesn’t react with iron
• buffering agent– ammonium carbonate
– maintains pH at 7-11
• minimum iron solubility
![Page 10: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/10.jpg)
12.011.010.09.08.07.06.0
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
pH
Eh
(V
olt
s)
Cu
Cu2(OH)2CO3 Cu(NH3)42+ Cu2(OH)2CO3
Cu2O
![Page 11: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/11.jpg)
• both NH3 and (NH4)2CO3 needed– (NH4)2CO3 controls pH
– NH3 dissolves the copper• Cu2+ + 4NH3 = Cu(NH3)4
2+
• 1.0 kg NH3 = 0.93 kg Cu
• high free NH3
– increased copper tenor in solution
– faster kinetics
– increased extraction of ammonia during SX
– loss of NH3 increases
![Page 12: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/12.jpg)
solvent extraction, SX
• loading
2RH + Cu(NH3)42+ = R2Cu + 2H+ + 4NH3
RH + NH3 = RH.NH3R = LIX84-IC
loading
1
loading
2
PLS
depleted org
loading
1
loading
2
loading
1
loading
2
PLS raffinate
depleted orgloaded org
![Page 13: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/13.jpg)
Extraction with LIX 84
[Meta
l] i
n o
rgan
ic, g
/L
[NH
3]
in o
rg, p
pm
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10 12
pH
0
50
100
150
200
250
300
Cu
Fe(III)
NiCo
Zn
NH3
![Page 14: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/14.jpg)
High SX transfers>0.48 g/ L / %extractant for ammoniacal system
~0.25 g/ L / %extractant for acid system
smaller SX plant required
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Cu in aqueous (g/L)
Cu
in
org
an
ic (
g/L
)
A/O = 1
8% LIX84-i
0
1
2
3
4
5
0 0.5 1 1.5 2 2.5 3
8.7% LIX984N
A/O = 1
0
1
2
3
4
5
0 0.5 1 1.5 2 2.5 3
8.7% LIX984N
A/O = 1
![Page 15: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/15.jpg)
solvent extraction, SX
• loading
– stage 1
• high Cu, low free NH3 in aqueous
– high 2RH + Cu(NH3)42+ = R2Cu + 2H+ + 4NH3
– low RH + NH3 = RH.NH3
– stage 2
• low Cu, high free NH3 in aqueous
– low 2RH + Cu(NH3)42+ = R2Cu + 2H+ + 4NH3
– high RH + NH3 = RH.NH3
• most ammonia loads in stage 2
![Page 16: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/16.jpg)
solvent extraction, SX
• ammonia will strip with acid
– ammonium build-up in electrolyte
– precipitation of ammonium sulphate
• minimise ammonia transferring to EW
– scrubbing of loaded organic
– minimise loading
![Page 17: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/17.jpg)
solvent extraction, SX
• scrubbing
– low pH strips NH3
80
82
84
86
88
90
92
94
96
98
100
5 6 7 8 9
equilibrium pH
% N
H3
str
ipp
ed
0
50
100
150
200
250
300
pp
m N
H3
in o
rgan
ic
![Page 18: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/18.jpg)
solvent extraction, SX
• scrubbing
CO2 + H2O = H+ + HCO3-
RH.NH3 + H+ = RH + NH4+
washing
1
washing
2loaded org strip
H2O
CO2
H2O
CO2
carbonate ppt
![Page 19: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/19.jpg)
solvent extraction, SX
2RH.NH3 + Cu(NH3)42+ = R2Cu + 2H+ + 6NH3
Cu crowds NH3 off the remaining extractant
loading
1
loading
2
PLS
depleted org
loading
1
loading
2
loading
1
loading
2
PLS raffinate
depleted orgloaded org
![Page 20: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/20.jpg)
solvent extraction, SX
• scrubbing stage– reduced to single stage
– now mostly defunct for ammonia
– CO2 storage and handling requirement reduced• dilute electrolyte can also be used as scrub solution
– Cu2+ and H+ both displace NH3
– scrub solution recycled to heap
– removes CO2 handling completely
– can be used to selectively remove other metals• Ni, Co, Zn etc
![Page 21: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/21.jpg)
solvent extraction, SX
• stripping stage
– standard spent electrolyte
• 175 g/L H2SO4, 35 g/L Cu
– loaded electrolyte
• 150 g/L H2SO4, 52 g/L Cu
![Page 22: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/22.jpg)
Flowsheet
electrowinning
CuH2SO4
stripping
heap leach
cure solution
cathodes
pH 3crud removal
metal recovery
or disposal
LIX-84i in kerosene
loading
silver recovery
Ni, Co, Zn
wash
bleed impurities
CaCO3
R2Cu R2Cu
R
Cu
NH3
NH3
NH3
![Page 23: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/23.jpg)
Flowsheet
electrowinning
CuH2SO4
stripping
heap leach
cure solution
cathodes
pH 3crud removal
metal recovery
or disposal
LIX-84i in kerosene
loading
silver recovery
Ni, Co, Zn
wash
bleed impurities
CaCO3
R2Cu R2Cu
R
Cu
NH3
NH3
NH3
may not be
necessary
![Page 24: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/24.jpg)
Leon pilot plant
![Page 25: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/25.jpg)
Leon pilot plant
• ore
– 0.84% Cu / 20ppm Ag in dolomite matrix
– 500kg H2SO4 / t
• 6 modules 400t each
• 150 days operation
• 50kg LME A Cu / day
![Page 26: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/26.jpg)
Leon cure stage
• HClO – hypochlorite, 1.6 g/L– oxidising agent
• Cu2S => malachite + SO4 + S
• Ag => AgCl (Cl 3g/L in plant water)
• Ag2S => AgCl + SO4
• also ammonia consuming organics
• NH3 – ammonia, 78 g/L– complexing agent
• malachite => Cu(NH3)42+
• azurite => Cu(NH3)42+
– transports copper to surface of rocks
• reprecipitation of malachite at surface of rocks
![Page 27: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/27.jpg)
![Page 28: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/28.jpg)
![Page 29: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/29.jpg)
Leon leach stage
• 20g/L (NH4)2CO3 + 10g/L NH3
– free ammonia matches leaching rate• Cu2+ + 4NH3 = Cu(NH3)4
2+
• 1.0 kg NH3 = 0.93 kg Cu
– minimal free NH3
• decreases losses to atmosphere
• <1kg/t on uncovered test heap
![Page 30: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/30.jpg)
Leaching performance pilot plant II<4” Caliza ore
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80 100 120 140 160
days
% C
u l
each
ed
module 1
module 2
module 3
module 4
module 5
module 6
acid recovery
![Page 31: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/31.jpg)
Leaching performance 5m columns<2” Caliza or Arenisca or 80/20 blend
0
20
40
60
80
100
0 20 40 60 80 100 120
time / days
%C
u l
each
ed
100% Caliza 100% Caliza 100% Arenisca 100% Arenisca
blend blend blend blend
![Page 32: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/32.jpg)
Parameter Acid AmmLeach
mineralogy oxides, carbonates, silicates,
some sulphides
almost any – dependant upon
curing stage
curing concentrated H2SO4 tailored to ore mineralogy
selectivity Low- iron, manganese, calcium
and silica are likely problems
High- no iron, manganese, calcium
or silica dissolution
rate of extraction limited by acid strength and
diffusion
ammonia concentration in leach
solution matched to leaching rate
recovery 80% of leachable >60% in 70 days
heap lifetime 55-480 days ~80-100 days
leachant
consumption
depends upon carbonate content
3.7-27 kg/t reported
depends on concentration used
<1 kg/t in preliminary pilot heap
![Page 33: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/33.jpg)
Parameter Acid AmmLeach
safety concentrated acid required gaseous ammonia main hazard,
on-demand systems using
hydrolysis of urea minimise
transport risks
precious metals heap to be neutralised before
cyanidation
neutralisation not required, potential
for simultaneous recovery using
thiosulphate or sequential leaching
using cyanide
decommissioning heap requires washing,
neutralisation and long term
monitoring to avoid AMD
heap can be washed and left,
residual ammonia acts as fertiliser
for vegetation regrowth,
minimal likelihood of AMD.
sulphate
precipitation
reduced permeability in heap,
break down of clays and plant
scaling due to precipitation of
gypsum and jarosite
calcium and iron solubilities too low
for precipitation, also low sulphate
levels in leach solution
![Page 34: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/34.jpg)
Oxide Zinc
![Page 35: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/35.jpg)
Zinc solubility
1614121086420
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
-1.4
-1.6
pH
Eh
(V
olt
s)
Zn
ZnO
ZnO
Zn(N
H3 )
42+
ZnO
22-
Zn2+
Skorpion
AmmLeach
![Page 36: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/36.jpg)
Zinc mineral solubilities in AmmLeach
• >90% soluble in 1h
– zincite ZnO
– hydrozincite 2ZnCO3.3Zn(OH)2
– ZINC CALCINE
• >50% soluble in 4h
– smithsonite ZnCO3
– hemimorphite H2Zn2SiO5
• <10% solubility in 168h
– franklinite, ZnFe2O4
– willemite Zn2SiO4
– sphalerite, ZnS **NOTE: with appropriate curing ZnS can be completely solubilised
![Page 37: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/37.jpg)
Solution purity for EW• Cu mg/l < 0.2
• Cd mg/l < 2
• Pb mg/l 0.2 – 2.0
• Co mg/l <0.5
• Ni mg/l <0.1
• As + Sb mg/l <0.1
• Cl mg/l 50 - 200
• F mg/l 1 - 20
![Page 38: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/38.jpg)
difficult to achieve purity with SX
• Skorpion, Namibia• multistage SX to clean solution for EW
![Page 39: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/39.jpg)
difficult to achieve purity with SX
RLE processes use cementation
Zn recycled
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
%re
cyc
le
![Page 40: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/40.jpg)
element
Zn
Cd
Fe
Si
Co
Ni
Cu
Ge
As
Sb
Pb
Cl
F
acid
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
AmmLeach
✓
✓
✓
✓
✓
?
?
NOTES
most removed during SX
ppts
insoluble
most removed during SX
most removed during SX
most removed during SX
sorbs onto iron ppt
sorbs onto iron ppt
sorbs onto iron ppt
insoluble
under investigation
under investigation
![Page 41: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/41.jpg)
Zinc solvent extraction
![Page 42: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/42.jpg)
0
2
4
6
8
10
12
0 1 2 3 4 5
g/L Zn in aqueous
g/L
Zn
in
org
an
ic
• zinc SX from ammoniacal solution
![Page 43: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/43.jpg)
0
20
40
60
80
100
120
0 50 100
g/L Zn in
g/L
Zn o
ut
• acid stripping of zinc from organic loaded
using ammoniacal solution
![Page 44: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/44.jpg)
Current RLE flowsheet
roaster leach electrowinning
acid plant
multistage
cementation
SO2
H2SO4
Zn dust
Fe precipitate
Fe
precipitation
ZnS
O2
Cu+Ni
insolubleferrite leach
insoluble
roaster leach electrowinning
acid plant
SO2
H2SO4
Zn dust
Zn cathode
Fe precipitate
Fe
precipitation
ZnS
O2
insolubleferrite leach
insoluble
Cd Co+As
![Page 45: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/45.jpg)
AmmLeach RLE flowsheet
roaster
acid plantH
ZnSZnS
cementation
SX
stripping
metal ppt
SX
loading
SO2
O2
H2SO4
H2SO4
raffinateZn2+
electrowinning
cathodes
Zn dust
tank leach
![Page 46: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/46.jpg)
AmmLeach RLE flowsheet
roaster
acid plant
ZnSZnS
cementation
SX
stripping
metal ppt
SX
loading
electrowinning
cathodes
Zn dust
tank leach
not required
or bleed
SO2
O2
H2SO4
H2SO4
raffinateZn2+
![Page 47: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/47.jpg)
Parameter Acid AmmLeach
mineralogy oxides, carbonates, silicates, some
sulphides
oxides, carbonates, silicates, some
sulphides
curing ore specific - likely to be none
selectivity low - iron, manganese, calcium and
silica are likely problems
high - no iron, manganese, calcium
or silica dissolution
rate of
extraction
limited by acid strength and diffusion ammonia concentration in leach
solution matched to leaching rate
sulphate
precipitation
reduced permeability in heap
break down of clays and
plant scaling by gypsum and jarosite
calcium and iron solubilities too low
for precipitation, also low sulphate
levels in leach solution
leachant
consumption
ore dependant reagents are recycled and losses
are very low
solvent extraction
and
stripping
requires considerable solution
manipulation, involving
cementation/precipitation to remove
iron, manganese and calcium
because of low selectivity for zinc
extraction into the organic phase
highly selective for zinc and
significant advance of previously
reported extraction efficiencies
safety concentrated acid required gaseous ammonia main hazard,
on -demand systems using
hydrolysis of urea minimises
transport risks
![Page 48: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/48.jpg)
• nickel and cobalt from lateritic deposits;
• gold, silver and copper in leached porphyries;
• polymetallic base metal deposits, especially U;
• leaching of metals from roaster concentrates;
• preleaching copper from copper-gold ores
Other applications
![Page 49: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/49.jpg)
![Page 50: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/50.jpg)
KEY FEATURES
• leaches base metal sulphides including– chalcopyrite, bornite, chalcocite, enargite
– millerite, pentlandite, pyrrhotite, violarite
– sphalerite
• ambient temperature
• ambient pressure
• heap leach or tank leaching
• rapid kinetics
• selective for sphalerite over galena
• selective for Ni-sulphides over pyrite
• low reagent consumptions
![Page 51: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/51.jpg)
Controlled pH increases oxidant concentration tenfold
![Page 52: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/52.jpg)
Nickel
![Page 53: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/53.jpg)
Nickelpentlandite / pyrrhotite flotation concentrate (15% Ni)
3.0 4.0 4.1 4.7 6.1 12.6
0
20
40
60
80
100
3.0 4.0 4.1 4.7 6.1 12.6
starting pH
%N
i le
ach
ed
@ 1
h
3.0 4.0 4.1 4.7 6.1 12.6
0
20
40
60
80
100
3.0 4.0 4.1 4.7 6.1 12.6
starting pH
%N
i le
ach
ed
@ 1
h
![Page 54: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/54.jpg)
Nickelreagent consumption
Head-grade
%Ni
%
leached
Ni Fe
mass loss
%
kg Cl2/ kg Ni
pentlandite / pyrrhotite
specimen10 93.7 61.1 39.7 4.6
low grade ore 1.6 85.7 0.0 2.5 4.8
NOTE: careful control of the pH for the low grade ore resulted in complete iron precipitation.
![Page 55: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/55.jpg)
Nickelpost-leach options
Option CAPEX OPEX complexity Notes
selective ppt as hydroxide low low lowhydroxide sold to existing refinery,
e.g. BHPBilliton’s Yabulu
iron ppt, Ni/Co SX, ppt as
separate hydroxide / sulphidemedium medium medium
high grade intermediates sold to
existing refinery
iron ppt, Ni/Co SX, metal EW high high high complex flowsheet
![Page 56: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/56.jpg)
Nickelother processes
Process DeveloperFeed
%Ni
P80
(μm)
temp
(ºC)
pressure
atmNotes
BioNIC BHP Billiton 4–12 75 30–40 1 dilute H2SO4 and bacteria
Intec Ni Intec 3–6 25 80–90 1aeration, acid pre-leach, and Br/Cl
leach
ActivoxWestern Min.
Tech.4–12 10 100 10 O2
CESL Ni Cominco 8–15 45 150 14 O2, HCl
Sherritt
GordonSherritt 20–70 75 150 10 matte leach using NH3 and O2
HyperLeach Alexander 0.7-70 * 25 1works on low grade ore,
concentrates and matte
* varies with feed
![Page 57: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/57.jpg)
Copper
![Page 58: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/58.jpg)
Copperminerals
0
20
40
60
80
100
0 2 4 6 8
starting pH
%C
u l
ea
che
d @
1h
enargite
chalcopyritebornite
covellite
0
20
40
60
80
100
0 2 4 6 8
starting pH
%C
u l
ea
che
d @
1h
enargite
chalcopyritebornite
covellite
0
20
40
60
80
100
0 2 4 6 8
starting pH
%C
u l
ea
che
d @
1h
enargite
chalcopyritebornite
covellite
0
20
40
60
80
100
0 2 4 6 8
starting pH
%C
u l
ea
che
d @
1h
enargite
chalcopyritebornite
covellite
![Page 59: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/59.jpg)
Copperreagent consumption
Head-grade
%Cu
leached
%
mass loss
%
solution
tenor g/L
kg Cl2/ kg Cu
chalcopyrite / bornite conc 26.6 54 43.8 1.4 3.5
chalcopyrite conc 29.1 51 40.1 1.5 3.3
covellite 79.3 72.8 70.5 5.8 0.6
low grade chalcopyrite ore 3.18 >99 3.1 0.35 7.9
NOTE: the high consumption for the low grade chalcopyrite was due to host rock being
a carbonaceous shale.
![Page 60: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/60.jpg)
Copperother processes
Process Developer OC pressure P80 mm notes
Activox XstrataNickel 110 9 <10 high oxygen overcomes chalcopyrite passivation
Albion XstrataTech 85 1 <10 ferric chloride leaching
UBC / AARL UBC / AARL 150 10-12 <15 surfactants used to overcome elemental sulphur
Galvanox UBC/ Bateman 80 1 75 pyrite recycle aids chalcopyrite leaching
BioCop BHPBilliton 80 1 22 thermophilic bacteria used
Bioleach numerous35-50
65-75
1
1
5-20
37
very fine grind essential
uses thermophilic bacteria
CESL Cominco 165 15 37 chloride catalysed
Dynatec Sherritt-Gordon 150 13 37 low grade coal used to control elemental sulphur
Total POx Phelps-Dodge 200-230 30-40 53 extreme T and P - indiscriminate
Hydrocopper Outokumpo 85-95 1 n/a 250-300g/L NaCl
Intec Copper Intec Ltd 85-95 1 n/a mixed Br/Cl leachant
HyperLeach Alexander 25 1 optimum grind size to be determined
![Page 61: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/61.jpg)
Lead - zinc
![Page 62: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/62.jpg)
Lead – zincminerals
0
20
40
60
80
100
0 2 4 6 8
start pH
galena
sphalerite
0
20
40
60
80
100
0 2 4
start pH
% l
eac
hed
@ 1
h
galena
sphalerite
0
20
40
60
80
100
0 2 4 6 8
start pH
galena
sphalerite
0
20
40
60
80
100
0 2 4
start pH
% l
eac
hed
@ 1
h
galena
sphalerite
![Page 63: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/63.jpg)
Lead – zincconcentrate cleaning
headgrade
%
leached
%
residue
% (calculated)
Zn 5.45 87.2 0.93
Cu 3.4 64.2 1.63
Pb 52.23 1.7 68.7
![Page 64: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/64.jpg)
Other applications
HEAP LEACHING
• nickel sulphide ores
• copper sulphide ores
• native copper ores
• mixed copper sulphide / oxide ores
• copper-gold ores
• uranium
• molybdenum sulphide / oxide
TANK LEACHING
• nickel sulphide concentrates
• nickel mattes
• copper flotation concentrates
• arsenical copper ores
• arsenical gold ores
• gold bearing sulphides
• concentrate cleaning
• PGM bearing sulphides / matte
• molybdenum sulphide
![Page 65: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/65.jpg)
Costs
MineralRange of Hypochlorite Operating
costs US$/lb metal produced
chalcopyrite CuFeS2 $0.45-$0.90
pentlandite (Ni,Fe)9S8 $0.60-$1.20
sphalerite ZnS $0.40-$0.90
These costs are based upon chlorine costs of US$300-600 per tonne.
![Page 66: Disclaimer - Metaleach](https://reader033.vdocument.in/reader033/viewer/2022050407/62708c9be58ec934c47e57c7/html5/thumbnails/66.jpg)
Summary
• leaches base metal sulphides including chalcopyrite, bornite, chalcocite, millerite, pentlandite, pyrrhotite, violarite, sphalerite and enargite;
• rapid kinetics at ambient temperatures and pressure;
• suitable for heap leaching as well as tank leaching;
• does not require chlorine gas to operate;
• oxidant generated on-demand and on-site via chlor-alkali technology; low reagent consumption;
• polymetallic deposits can be readily handled using standard solvent extraction and solution purification techniques; and
• less environmentally harmful than smelting