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Nickel Ore Processing Trends

The Rise of Nickel Laterites and Advances in Sulphide

Processing

j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE

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Outline

• Introduction to nickel – sources and uses

• Look at the market and some interesting production statistics

• Today’s nickel processing status − Brief overview of hydrometallurgical and pyrometallurgical processes

> Their current market contribution

> Current Projects/Operations

> Process Pros and Problems

• The future of nickel processing − Overview of proposed/pipeline processes for sulphides and laterites


Nickel Sources

• 30% of world nickel is in sulphidic form, 70% is lateritic nickel

• Image (Butt, 2007).


Processing Background and Nickel

Uses

What do we use nickel for?

− About 70% of nickel goes into making steel (in China & also Japan)

− The remaining 30% goes into specialty products: batteries, electronics, turbines etc.

How have we traditionally sourced it?

• Sulphides have been the dominant source of nickel through the

1900’s. − Higher grades than laterites

− Processing cheaper than laterites (upgrading)

− High grade sulphide reserve levels not an issue

• Laterites have not contributed as significantly to the market until recent

times - 30% world production in 1990


Laterite/Sulphide Mine Production

Trends

• Note that Indonesia has recently banned ore exports! This is putting

pressure on supply as China/Japan have to source nickel from elsewhere

in the interim (Philippines) – nickel price has risen 37% this year (dropped

6.5 % very recently due to underestimated stockpiles)


Processing Trends by Ore Type

• >50 % of the mined laterite ore (previous slide) from the Philippines is

actually processed as iron ore.

• A lot of stockpiling in China has also reduced impact of mined ore on

actual production.


Processing Trends by Process


Sulphide Access and Availability

• Sulphides are still a major nickel source

• Rate of consumption exceeds rate of new deposit discovery

• Major ore types: − Massive sulphide – historically relied upon – largely gone

− Disseminated sulphides – what we are largely left with

− Today’s economic sulphide grades – 0.2 to 2%

• Mining sulphides − NiS is formed as a result of volcanic and hydrothermal activities

− Open cut mines

− Underground mines (primarily)


Magmatic Sulphide Deposit Profile

• Orthomagmatic Nickel Sulphide Deposit Model

• Many classifications of sulphide deposits

• What is important to know from a processing point of view: − Massive sulphides (VMS) – upgrade well

− Disseminated sulphides


Sulphide Processing

• Pyrometallurgical processes are still predominant − Flash furnaces are the conventional smelting route

• Hydrometallurgy is an emerging trend in sulphide processing due to: − Environmental pressures

− Lower grades

• Commercially applied processes include: − Pressure Oxidation (POX)

• Processes in Development include: − ACTIVOX

− CESL

− Platsol

− The Albion Process

− Bio-Heap Leaching


Sulphide Pyrometallurgy – Smelting

• Production: − 90+% of sulphide processing

− 40% of world nickel production

• Process: − Beneficiation

− Roasting

− Smelting

− Refining – not our focus today

Pros Problems

Sulphide oxidation is exothermic SO2 production

Widely known and understood Arsenic emissions

Suitable ores running out


Sulphide Hydrometallurgy - POX

• Process: − Comminution

− Atmospheric chloride pre-leach

− Pressure Oxidation leach

> Pure oxygen

> 22-27 bar

> 200oC

− Impurity precipitation - MHP product

• Projects: − Voisey’s Bay, Canada, 50 ktpa finished nickel

Pros Problems

Can process arsenic-bearing ores Chlorine gas handling

No SO2 produced Requires water and tailings disposal

facilities

Good cobalt extraction Limited ore applications

High pressure/temperatures


Sulphide Hydrometallurgy - CESL

• Process − Comminution – 25 to 45 micron

− Pressure Oxidation Leach

> Sulphuric acid / chloride mix

> Pure oxygen

> 14 bar

> 150oC

− Impurity precipitation - MHP product

• Projects − Process developed by Teck Resources

− Vale Salobo copper project – piloted in 2008

Selling Points

Can deal with low grade concentrates (3%)

Can deal with high Mg-bearing ores

Laterite application has been investigated


Sulphide Hydrometallurgy - ACTIVOX

• Process − Ultrafine grinding

− Pressure Oxidation Leach

> Sulphuric acid

> Pure oxygen

> 10 bar

> 100oC

− CCDs

− MHP product

• Projects − Developed by WMT in Perth

− Tati Nickel, Botswana

Selling Points

Milder conditions than POX/CESL


Sulphide Hydrometallurgy - Albion

• Process − Isamill grinding

− Oxidation leach

> 1 bar

> 70oC

> Supersonic pure oxygen

− CCDs, impurity removal, MHP

• Projects − Developed by MIM (Xstrata) in 1994

− Two zinc, two gold plants

Pros Problems

Atmospheric conditions - CAPEX Isamill energy intensive

Low reagents - OPEX


Sulphide Hydrometallurgy - Platsol

• Process − Grinding

> 120 micron

− Pressure oxidation leach

> Sulphuric acid generation

> NaCl added to leach (dissolves PGMs)

> 25 bar

> 220oC

• Projects − SGS holds the patent

− PolyMet Mining, NorthMet Project - developmental

Selling Points

Used to treat PGMs


Summary of Vessel Processes

Pressure

(bar) Temperature

(C) P80 Grind Size

(micron) Residence

Time (hours)

POX 27 200-225 20 (Voisey’s) 2

Platsol 27 220 120

CESL 14 150 25 to 45

ACTIVOX 10 100-110 5 to 15

Albion 1 70-90 10 to 15 24


Sulphide Hydrometallurgy – Bio Heap

Leaching

• Process − Agglomeration + Heap construction

− Bacteria and dilute sulphuric acid leach

> Atmospheric

> Autothermal

− No CCDs required

− Impurity removal, intermediate product

• Projects − Western Areas – testing

− Talvivaara, Finland - online

− Jinchuan, China – pilot

Pros

Avoid fine grinding

Low reagents

Autothermal

Applicable to low grades

Low environmental impact

Problems

Large footprint

Long residence time

Heap leach issues


Laterites

• Economic grades - 1.3 to 1.8% − Saprolite typically 1.5 to 3% Ni

− Limonite typically 1.2 to 1.7% Ni

• Beneficiation difficult

• Current pyrometallurgical dealing with laterites − Ferronickel Smelting – Fe-Ni

− Nickel Pig Iron Smelting – NPI

• Current hydrometallurgical dealing with laterites − The Caron Process (pyro/hydro hybrid) – Majority

− HPAL (High Pressure Acid leaching) – Majority

− HPAL combined with AL (Atmospheric Leaching)

− HL (Heap Leaching)


Laterites - Profile

• Form in the “oxidised zone”

• Laterites are generally more accessible than sulphide ores from a

mining perspective – all open cut as a result of shallow ore bodies

• Generalised ore body profile:


Laterite Pyrometallurgy - Background

• 40% primary production in 2012

• Fe-Ni/NPI - What’s the difference? − Fe-Ni has an ISO classification

− NPI does not have a standard

• Uses: − Fe-Ni - 300 series of steels (e.g. 304, 316)

− NPI - 200 series of steels (construction steels)

• NPI - 19th century technology – − China brought it back to life in 2006

− A “last resort” alternative


Laterite Pyrometallurgy - Ferronickel

• Process − Saprolite feedstock – Fe, Mg, Ni ratio

− Calcining 1000oC

− Smelting in RKEFs 1550oC

− Refining

• Projects − Onca Puma, Brazil (50 ktpa)

− Koniambo, New Caledonia (60 ktpa)

− Gwanyang, South Korea (30 ktpa)

− …

Pros Problems

Well understood technology Energy intensive

Environmental issues

Commercially sensitive


Laterite Pyrometallurgy – Nickel Pig Iron

(NPI)

• Process: − Used with limonite

− Roasting

− Smelting - Blast furnaces, submerged arc furnaces

− Refining

• Projects: − More than 30 producers in China – 100 ktpa+

Pros Problems

Well understood technology Energy intensive

Robust – lim. and sap. Emissions

Commercially sensitive

Low grade product


Laterite Hydrometallurgy - The Caron

Process

• Process − Limonite feedstock

− Calcination 850oC

− Ammonia leach/quench (150-200oC)

• Projects − Yubulu, Australia (1974)

− Punta Gorda, Cuba (1986)

− Nicaro, Cuba (1944)

Issues

Ni/Co recoveries < HPAL

Limited to low Mg ores

No longer viable greenfield process


Laterite Hydrometallurgy - Pressure

Leaching (PAL/HPAL)

• Process: − Limonite feedstock (low magnesium)

− High pressure autoclaves

> Sulphuric acid

> PAL – 4 bar; HPAL – 30 bar

> 240-270oC

> Hydrolysis reaction

− Energy recovery

− CCDs

− Impurity removal

− Intermediate product

• Projects: − Moa Bay, Cuba

− Murrin Murrin, Australia

− Bulong and Cawse, Australia

− Ambatovy, Madagascar

− Goro Nickel Project

Pros

Can handle arsenic feeds

Good recoveries (>95% Ni&Co)

Fast reaction times

Cobalt credits

Problems

Exotic equipment

Commercial risk

Maintenance


Laterite Hydrometallurgy – HPAL +

Atmospheric Leaching (AL)

• Process: − PAL deals with limonite feed

− AL takes PAL discharge and neutralises with saprolite


− MHP/MSP product

• Projects − Ravensthorpe, Australia - EPAL – 38 ktpa 2013

Pros Problems

Utilises saprolite and limonite ore High CAPEX

Problems associated with PAL

Higher complexity


Laterite Hydrometallurgy - Heap

Leaching (HL)

• Process − No beneficiation

− Agglomerate all ore

− Put on heap

> Sulfuric acid

> Atmospheric conditions

− No CCDs, impurity removal, Intermediate

product

• Projects: − Çaldağ, Turkey

− Acoje, Philippines

− Murrin Murrin, WA

− Yunnan Yuanjiang Nickel Project, China

− Niquel do Piaui, Brazil

− …

Pros

Low CAPEX/OPEX

Simple

Applicable to low grade

Robust (lim. & sap.)

Problems

Heap permeability

Water management


Laterite Hydrometallurgy - Bioleaching

• Process − Heap leach or agitated tanks

− Microbes mixed with sucrose/glucose

− Oxalic/citric acid leach

• Projects: − Very early stages, no commercial projects

Selling Points Potential Problems

Tailings, emissions Requires bacteria food source

Doesn’t require mineral acids Residence time


In the Works – AL

• Process − Atmospheric leach on limonite

− Saprolite neutralisation

• Projects: − Weda Bay, Indonesia – development

− Oriel resources - exploring

− Heron Resources - exploring

− Metallica Minerals - exploring

Selling Points Potential Problems

Atmospheric conditions Residence time – 12 hours

Less complex Capital still high

Lower energy concsumption Requires correct blend

Iron & acid consumption


In the Works - SAL

• Process: − Limonite ore & conc. Sulphuric acid go into pug mill

− Crushed saprolite and water enter the grinding circuit

− Leach

> 1 bar

> 100oC

− CCDs


− Intermediate product

• Projects: − Skye Resources, Fenix Project, Guatemala – pilot

Selling Points

Mild conditions

Robust (limonite & saprolite)


In The Works – Atmospheric Chloride

Leaching (ACLP)

• Process: − Crushing & grinding

− Leaching

> 1 bar

> 100oC

> Hydrochloric acid

− Regeneration of hydrochloric and magnesite

• Projects: − Jaguar Nickel – piloted 2004

− Jervois mining – explored 2004

− Intec Nickel – piloted with gold 2003

Selling Points

Mild conditions (HCl)


Regeneration of reagents


• Process: − Crushing & grinding

− Leaching

> 1 bar

> 100-170oC

> Nitric acid

− CCDs


− intermediate

• Projects: − Direct nickel piloted in 2013

− Feasibility with PT Antam

In The Works – Atmospheric Nitric Acid

Leaching (DNi)

Selling Points

Mild conditions (NOx)


Regeneration of reagents

Hematite by-product

Can use 304/316 SS


Final Words

• Shifting process pressures − Feedstock changes

− Environmental legislation

− Nickel demand

• New processes looking at: − Process robustness

− Lower grades

− Environmental impacts

− Energy consumption

− By-product subsidisation

− Lowering CAPEX

− Complexity


References

• Butts, C 2007, Nickel Deposits: Laterites and Sulphides,

Presentation for World Nickel Supply Plot

• INSG, July 2013, Sulphide Ore Production Stops Growing, Maquarie

Research

• INSG, July 2013, Laterite Nickel Mine Production Takes Off,

Maquarie Research

• INSG, July 2013, Finished Nickel Production by Ore Type, Maquarie

Research

• INSG, July 2013, Finished Nickel Production by Main Process,

Maquarie Research

• INSG, July 2013, Share of Nickel Production by Process, Maquarie

Research

• D. Houston 1999, Idealised Composite Intrusion Showing Diverse

Stratigraphic Positions of Selected PGE Deposits

• Hatch Associates Limited 2012, Chinese Nickel or Imports by

Country


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