platinum group elements - nstf

Advanced Manufacturing & Automation: Platinum Group Metals

PLATINUM GROUP ELEMENTS:MINERALS TO METALS AND BEYOND

D.L. Reid Department of Geological Sciences, University of Cape Town


1. FUNDAMENTALS 5. EXPLORATION

2. APPLICATIONS 6. ECONOMICAL FACTORS

3. SUPPLY AND DEMAND 7. FUTURE PROSPECTS

4. MINING AND PROCESSING

PLATINUM GROUP ELEMENTS:


PGE - Platinum Group Elements (N = 6)

44Ru 45Rh 46Pd 76Ir 77Os 78Pt

PGM - Platinum Group Metals

Precious; Noble; Heavy; Siderophile; Chalcophile

or Platinum Group Minerals

FUNDAMENTALS


Patinum Group Elements

PGE


PRIMORDIAL FORMATION:

NUCLEI - ATOMS - MINERALS 1.0 - ROCKS 1.0

PLANETARY FORMATION:

ROCKS 1.0 - MAGMAS 1.0 - MINERALS 2.0 - ROCKS 2.0 - CORE - MANTLE

(2.1) (2.2)

PLANETARY CONVECTION:

ROCKS 2.2 - MAGMAS 2.0 - MINERALS 3.0 - ROCKS 3.0 (CRUST)

FUNDAMENTALS


Nuclei

up to FeH - He

Up to U

PGEs

FUNDAMENTALS

CONDENSATION

Atoms

Minerals 1.0

Rocks 1.0


BIG BANG !

STELLAR

FUSION

SUPER NOVAE

"Light"

PGE

"Heavy"

PGE

Ru-Rh-Pd Os-Ir-Pt

COSMIC

ABUNDANCES


FUNDAMENTALS

COSMIC

ABUNDANCES

PGES HAVE SIMILAR

COSMIC ABUNDANCES


FUNDAMENTALS


PLANETARY FORMATION:

ROCKS 1.0 - MAGMAS 1.0 - MINERALS 2.0 - ROCKS 2.0 - CORE - MANTLE

(2.1) (2.2)

COREFe ~ 88.8%

Ni ~ 5.8%

S ~ 4.5%

Others < 1% (PGE)

MANTLE

O 44% Ca 2.3%

Mg 23% Al 2.2%

Si 22% Na 0.3%

Fe 5.8% K 0.3%

PGE ~ PPB LEVELS


FUNDAMENTALSRELATIVE

ABUNDANCE IN

EARTH'S CRUST

SIDEROPHILES

GONE TO

THE CORE


Pt Pd Ru Rh Ir Os

Typical Bushveld PGE

Primordial


APPLICATIONS


SUPPLY/DEMAND


ECONOMICS


ECONOMICS

THE PAIN IS IN PRODUCTIVITY


MINING

Advanced Manufacturing & Automation: Platinum Group MetalsMINERAL PROCESSING


ECONOMICS


MINING


MERENSKY REEF

Merensky Melanorite

Merensky Chromitite

Pegmatoidal Melanorite

Footwall

Leuconorite

MINING


Merensky Melanorite

Merensky Chromitite

P2 Chromitite

Tarentaal Dunite

Pegmatoidal Melanorite/Harzburgite

MINING


NP2 REEF

Merensky Chromitite

Merensky Melanorite

Footwall Leuconorite

Troctolite

MINING


MERENSKY ORES

Spot the

Braggite

Crystal?

MINING


50 µ

PLATINUM ORES

BASE METAL SULPHIDES

Pyrrhotite Fe8S9

Chalcopyrite CuFeS2

Pentlandite NiFeS2

P G M

Braggite (Pt, Pd, Ni) S

MINING


NORMAL TYPE MERENSKY REEF: NORTHAM PLATINUM

FOV: 3.5 cm

Pegmatitic Pyroxenite

Interstitial Plagioclase

BMS

Use of XRCT to search

For PGM rich zones

MINERAL

PROCESSING



FOV: 3.5 cm

BMS NETWORK

Silicates Removed


For PGM rich zones

MINERAL

PROCESSING



PGM Distribution


For PGM rich zones

MINERAL

PROCESSING


BMS inclusions within cumulus opx, Merensky Meranorite

MINERAL

PROCESSING


Pegmatoidal

HarzburgiteP2 REEF BMS modes in pegmatoidal reef

1

2

3

MINERAL

PROCESSING


BMS trapped within annealed chromites

MERENSKY CHROMITITEMINERAL

PROCESSING


MINERAL PROCESSING


62%26%

6% 6%

Platinum-Group Minerals (PGM) Distribution-TRP 271

PtTeBi/PdTeBi Alloy

(

)PtTeBi = 62%)

(PdTeBi = 38%

Sulphides

ArsenidesOther alloys

45%

33%

22%


PtTeBi Alloy

Sulphides

Arsenides


65%

33%

2% (Arsenide)

PtTeBi AlloySulphides

MINERAL

PROCESSING


MINING & MINERAL

PROCESSING


MINING & MINERAL PROCESSING


MINERAL PROCESSING


REFINING


EXPLORATIONTHE PGE

CONCENTRATE

INSIDE MAGMA

CHAMBERS


EXPLORATION


EXPLORATION

EASTERN

BUSHVELD


EXPLORATION

SURFACE OUTCROP OF THE MERENSKY REEF - ATOK/BOKONI


EXPLORATION

SURFACE OUTCROP

OF THE MERENSKY

REEF - ATOK/BOKONI


EXPLORATION

Advanced Manufacturing & Automation: Platinum Group MetalsEXPLORATION


EXPLORATION


ORIGIN OF PLATINUM GROUP MINERALS

1. Exsolution from PGE enriched BMS

2. Crystallization from Sulphide Melt

3. Crystallization from Silicate Melt

4. Entrainment from source in Silicate Melt

5. Crystallization from PGE enriched fluids

SOME KEY QUESTIONS

1. How do the PGE occur in the magma?

Ions, neutral atoms, clusters,

nanominerals, xenocrysts

2. Why are the PGE so enriched in the

Bushveld Complex

EXPLORATION

WHEN?

HOW?

WHY?

WHERE?


ORIGIN OF PLATINUM GROUP MINERALS

1. Exsolution from PGE enriched BMS

2. Crystallization from Sulphide Melt

3. Crystallization from Silicate Melt

4. Entrainment from source in Silicate Melt

5. Crystallization from PGE enriched fluids

SEVERAL GENERATIONS OF PGM

1. Microscale

2. Nanoscale

3. PGE in solid solution

RESULTS

EXPLORATION

WHEN?

HOW?

WHY?

WHERE?


1. ExsolutionPost-Magmatic Cooling

Subsolidus Phase and Structural Changes

PGE NANOPHASES

2. Direct CrystallizationDirect from silicate magma

Subsequently included in silicates/oxides/sulphides

Direct from sulphide melt

3. Xenocrysts?No compelling evidence

EXPLORATION

WHEN?

HOW?

WHY?

WHERE?

50 nm


POSSIBLE ROLE OF PGE NANOPHASES

Bi-As-Sb-Te (BAST) important activators of

nano-associations

BAST effect could be crucial in

concentrating PGE

Migration/aggregation/collection of BAST

stabilised nano-phases

Sulphide melts and Chromite may be

BAST-ophilic, others maybe BAST-ophobic

EXPLORATION

WHEN?

HOW?

WHY?

WHERE?


PGE PRODUCTION QUICK FACTS

GLOBAL PRIMARY PRODUCTION OF PGES IN CURRENTLY ~450

mT (PLATINUM: 200 mT; PALLADIUM: 200 mT; RHODIUM: 30 mT)

SOUTH AFRICA AND RUSSIA TOGETHER PRODUCE AROUND

85% OF WORLD PRIMARY PGE SUPPLY

DEPOSITS IN RUSSIA AND NORTH AMERICA HAVE HIGH PD

WHILE DEPOSITS IN SOUTH AFRICA AND ZIMBABWE ARE

RICHER IN PT

95% OF THE KNOWN WORLD RESERVES ARE LOCATED IN

SOUTH AFRICA

30% OF PGES ARE PRODUCED AS CO-PRODUCTS OF

NI (+ CU-CO) MINING

TAKE THIS HOME 1


Mineable deposits of PGEs are very rare in the Earth’s crust

PGM mining is a capital, energy and labour intensive industry

Primary and secondary production (recycling) of PGMs are complementary and mutually-dependent

Primary and secondary production of PGEs create large revenues and thereby contribute greatly to the

economic growth and wealth of the countries where the metals are mined and processed

Primary production of PGEs - the transfer of metal from below ground resource to above ground

material stock - should be regarded as an investment

Annual PGM production is lower than the production of other metals; combined with the high

production costs of PGMs, this results in highly economical and responsible usage

TAKE THIS HOME 2


The six platinum group elements (PGEs) occur together in nature alongside nickel (Ni) and copper (Cu)

Mineable deposits of PGEs are very rare, with annual production amounting to around 400 mT, several

orders of magnitude lower than many common metals

Due to their economic values and higher quantities, platinum (Pt) and palladium (Pd) are the most

important metals of the PGEs

The other four, rhodium (Rh), ruthenium (Ru), iridium (Ir) and osmium (Os), are mined as by-products

of Pt and Pd

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Extraction, concentration and refining of PGEs require complex, costly and energy-intensive processes

that may take up to six months to produce refined metal from the time the first PGE-bearing ore is broken

in a mine


PGE-bearing ores in South Africa generally have a low PGE content of between 2 and 6 g/mT and it will

typically take up to six months and between 10 and 40 mT of ore to produce one ounce (31g) of

platinum

Most of the PGE mines in South Africa operate at a depth below 500 m and up to 2.5 km

Their orebodies are tabular and narrow, varying in width between 0.9 m and 2.1 m and requiring labour-

intensive mining techniques

PGE ore is drilled and broken with explosives before being removed through mechanical transportation

methods to the surface

Electricity consumption is high: drilling for blasting, ore haulage and to refrigerate the working areas

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On the surface the ore is crushed and milled into fine particles

Wet chemical treatment known as froth flotation produces a concentrate which is dried and smelted in an

electric furnace at temperatures over 1,500°C

A matte containing the valuable metals is transferred to converters to remove iron and sulphur

PGEs are then separated from the base metals nickel, copper and cobalt, and refined to a high level

of purity using a combination of solvent extraction, distillation and ion-exchange techniques.

Power consumption during mining and ore beneficiation and the emissions of SO2 and CO2 associated

with these two process steps are the major impacts of PGE production

In South Africa, more than 90% of electricity is generated through burning hard coal

The energy intensity of the PGE production process and the reliance of the industry on this energy source

leads to a relatively high global warming potential per unit of PGEs produced

TAKE THIS HOME 4


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