Hydrometallurgical Options to Add Value to Copper · PDF fileBacterial Leaching BIOX / BioCOP...
Transcript of Hydrometallurgical Options to Add Value to Copper · PDF fileBacterial Leaching BIOX / BioCOP...
Hydrometallurgical Options to Add Valueto Copper Projects and Operations
Peter Rohner
Core Resources, Brisbane
www.coreresources.com.au 24th March 2010
Company Overview
Highlights• Specialist services:
– hrltesting (metallurgical laboratory – operating over 25 years).– Marketing of licensed processing technology (Albion Process).– Process engineering, design and flowsheet development– Scoping and Feasibility Studies– Technology Development Partner
• Strong Technical Team:– Hydrometallurgical expertise– Flowsheet development with an economic focus and outcomes that can
be engineered and operated– Project development and commissioning experience
Copper Leach Flowsheets
In-SituLeaching
Metal RecoverySX/EW
SX/Crystallisation
Precipitation
CementationTailings
ROM ore
Products- Cathode- Sulphate- Cement- Oxide / Sulphide- Other
Dump/HeapLeaching
Concentration(Gravity /Flotation)
ROM ore
ROM ore
Leach Neutralisation
Lower Grade Concentrate
Residue
Acid
AlkalineSize
Fines
By-products- Gold/Silver- Cobalt- Molybdenum- Rhenium- Indium- Uranium- OtherConcentrate
- Lower Impurities (e.g. As,Sb)High GradeConcentrate
ROM ore
In-Situ Leaching• Minerals – Oxides• Lixiviant – Acid or Alkaline• Not widely applied, needs the right geology and permitting• e.g. Mount Gordon - QLD• e.g. Florence, Arizona ex- BHP Copper still on hold
Dump/Heap Leaching• Minerals – Oxides / Sulphides• Lixiviant – Acid or Alkaline (see AmmLeach later)• Widely applied• Pads – Permanent / On-off Pads e.g. Tintaya, Peru (On-off Pad)• e.g. Nifty - WA, Lady Annie - QLD
Copper Leach Flowsheets
Concentrate Leaching• Minerals – Oxides / Sulphides / Refractory Sulphides• Lixiviant – Acid/Alkaline• Processes
- Pressure Oxidation - BIOX- GEOCOAT - CESL- Albion Process - Galvanox- Many others
Copper Leach Flowsheets
AmmLeach• For high carbonate ores and other high acid consuming gangue minerals
(i.e. > 40kg acid/t of ore)• Ammonia used (typically ~3kg ammonia/t of ore)• Similar downstream circuits (SX/EW) and similar capital costs to acid leaching• Pilot Plant run at Leon Copper Project - Argentina in 2007.
Copper Leach Technologies
Pressure Oxidation
Mount Gordon• 1998 – A$93M plant commissioned and ran until 2004, converted to concentrate
production in 2004 as more chalcopyrite ore in feed. Currently on care andmaintenance. 44,000 t/y Cu capacity.
Freeport• 2002 – US$40M Bagdad plant commissioned – converted to Molybdenum
leaching plant in 2009. 15,000 t/y Cu capacity.• 2007 – US$240M Morenci plant commissioned – currently shut down. 70,000 t/y
Cu capacity.
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Copper Leach Technologies
Pressure Oxidation cont.
CESL• First demonstration plant for Vale in Carajás region of Brazil.• 2009 – US$58M plant commissioned. 10,000 t/y Cu capacity.• Pressure oxidation with chloride
Chelopech• 2011 – US$80M plant with 20,000 t/y Cu capacity.
Activox• Nickel demonstration plant commissioned, but no copper plant.
Copper Leach Technologies
Bacterial Leaching
BIOX / BioCOP• 2004 – US$50M Alliance Copper (BHP Billiton and Codelco) plant
commissioned. 20 000 t/y Cu capacity. The plant was shut down and wasconverted to smelter dust leaching.
GEOCOAT• No copper demonstration plant yet, a pyrite gold plant run in Africa .• Oxidation is typically complete within 45 to 120 days, depending on the
mineralogy.• Need a low carbonate support rock .• Temperature of a GEOCOAT® heap ranges from 25-70oC.• Working capital is significant.
Copper Leach Technologies
Albion Process• No copper demonstration plant yet although unit operations widely used.• Mount Isa Mines dust leach plant gradually to be converted to Albion Plant .• Uses fine grinding and oxidation at ~90oC under atmospheric pressure.• Oxidation is typically complete within 12 to 24 hours, depending on the
mineralogy.
Copper Leach Technologies
Nikko Chloride Process (“N-Chlo Process.”)• US$27M pilot plant being built in Perth now.• 100 t/y Cu capacity• Chloride leaching technology and solvent extraction technology
Galvanox Process• No demonstration plant yet.• Uses pyrite to catalyze reaction.• Atmospheric leach (~80oC).• Pure sulphate medium (no chloride).• No fine grinding.• Fully compatible with conventional SX-EW.
Copper Leach Technologies
Other Processes
HydroCopper - Outotec• Zangezur Copper-Molybdenum Combine CJSC project demonstration plant
operation in 2008-2009 in Finland.• Erdenet Mining Corporation demonstration plant operation at Outotec Research
Center, demonstration of the process technology at Pori, Finland in 2004.• Chloride based technology, using chlorine gas and hydrogen.
Intec• Demonstration plant was constructed and operated during 1998 and 1999 in
Sydney.• Complex chemistry using sodium chloride-sodium bromide electrolyte.• Copper EW from the cuprous (one electron) state.
Copper Leach Technologies
Opportunities to Add Value• Alternative products• By-products• In-situ acid production – reduce acid cost• Use of alternative neutralising materials – reduce neutralising cost• Impurity removal• Integrated flowsheets• Additional metal recovery• Key drivers
Copper Leach Flowsheets
Copper Cathode• Larger scale projects• Low/moderate power costs• Remote / high transport costs
Copper Sulphate• Premium over metal• Smaller scale projects• Power costs higher• Local demand – zinc flotation, fertilizer plant, feedlot
Other (Cement, Copper Sulphide, Copper Oxide)• Copper cement – concentrates or low cost scrap iron available• Intermediate product – market nearby or integrated flowsheet
Copper Leach Product Options
Cu2+ + Fe = Fe2+ + Cu
Smelters don’t pay for many of these elements
Leaching provides an opportunity to recover additionalvalue e.g. Cobalt, Molybdenum, Rhenium, Indium, Uranium
Copper Leach By-product Recovery
Oxide ore / Concentrate
Leach CircuitAir/ Oxygen
Acid
Copper SolventExtraction
Raffinate to Leach
Bleed to by-product recoveryand neutralisation
Advance to EW or Crystallisation
NeutralisationLimestone
Copper Leaching In-situ Acid Production
Oxide ore
Underlying secondaryand primary ore FLOTATION
Leach Circuit
Flotation Tailings
OxygenAcid
HEAP LEACH
SX/EW
Raffinate to Leach
Raffinate to Heap Leach
e.g. Freeport’sMorenci and Bagdad POXplants
Generate excess acid in leaching circuit for oxide leachSeparate pyrite oxidation circuit to generate acid - e.g. Sepon
Recover more pyrite to leachcircuit and oxidise
NeutralisationLimestone
Alternative Neutralising Materials
Oxide ore Concentrate
Leach CircuitOxygen
Acid
HEAP LEACH
SX/EW
Raffinate to Leach
Raffinate to Heap Leach
Turn neutralising stage from cost to a credite.g. Use copper oxide ore (high grade fines) or copper oxide concentrate instead
of limestone / lime.
Neutralisation
FinesCoarse
Impurity Removal
Many large undeveloped copper deposits havesignificant impurity issues.• Salobo, Brazil High Fluorine
• La Granja, Peru High Arsenic
• Tampakan, Philippines High Arsenic
• Nena, PNG High Arsenic
• Many other South AmericanCopper Projects High Arsenic
Core continues to be active further developing alkalineleaching technology to remove arsenic and antimonyfrom copper concentrates.
Copper Leaching / Smelter Synergies
Low Grade Concentrate Arsenic Rich Smelter Dust
Neutralisation
Copper Solution to Copper Recovery
LimestoneAir
Ferric ArsenateGypsum Residue
Leach CircuitOxygen
SmelterAcid
SolidLiquid
“IronSource”
Concentrate and Leaching Synergies
Case Study
Normal grade concentrate for sale
vs.
High grade concentrate for sale
plus
Low grade concentrate to leaching
Copper Recovery
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%C
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Copper Grade/Recovery
+ + + + ++
PerfectSeparation
Target ConcentrateGrade - 25% Cu
Liberated Chalcopyrite
Max. TheoreticalRecovery
Copper Recovery
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PerfectSeparationPlant Separation
Target ConcentrateGrade - 25% Cu
+
Liberated Chalcopyrite
Liberated Gangue recovered by "Entrainment" or "True" Flotation
Plant Recovery
Copper Recovery – Case Study
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Target ConcentrateGrade - 30% Cu
Liberated Chalcopyrite
30% Recovery toLower Grade Copper
Concentrate - 7.5% Cu
Concentrate forSale
Concentrate forLeaching
Case Study
Base Case• 1,500,000 tonnes per year of ore @ 2% Copper.• Conventional concentrate production – 80% Copper recovery• Sell concentrate – 96,000 tonnes @ 25% Copper grade
(24,000 tonnes of Copper contained)
Assumed Copper Price US$3.00 /lbTC US$50 /tRC US 5c /lb
Case Study
Alternative Hydromet. Case• 1,500,000 tonnes per year of ore @ 2% Copper.• High grade concentrate production – 60% Copper recovery• Sell high grade concentrate – 60,000 tonnes @ 30% Copper grade
(18,000 tonnes of Copper contained)
• Recover low grade concentrate and treat hydrometallurgically• Low grade concentrate – 120,000 tonnes at @ 7.5% Copper grade
( 9,000 tonnes of Copper contained)• Leach low grade concentrate – 90% Copper recovery to Copper Sulphate
product (8,100 tonnes of Copper contained)
• Total payable copper – 26,100 tonnes (vs. 24,000 for base case)
Case Study
Positives• Additional 2,100 tonnes of copper recovered• Higher revenue per tonne of copper (copper sulphate premium, higher payable
lower deduct)• Lower freight and treatment charges• Additional ~$30M in net revenue (from above)• Additional by-product revenue ?
Negatives• Additional leach circuit and product to handle / sell• Additional capital cost ~$50M, Additional leach circuit costs ~$10M
Conclusion• Robust project
Key drivers that provide opportunities
• Can only produce “dirty” unsaleable concentrates• Concentrate transport costs high - far from markets• Low power costs• Limestone/other neutralising material available and low cost• Acid available and low cost (or low power cost)• Existing infrastructure available (old oxide leaching operation SX/EW plant)• Local demand for copper sulphate or intermediate• Potential for by-products credits• Significant recovery improvements
Summary
Questions ?