REE Processing | A South African perspective · REE Beneficiation How rare are they….. U.S. Geological Survey Fact Sheet 087-02 cerium is the 25th most abundant element at 68 parts

REE Processing | A South African perspective

REE Beneficiation What are they…..

“The rare earth elements perplex us in our researches, baffle us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us

mocking, mystifying and murmuring strange revelations and possibilities. ”

Sir William Crookes

REE Beneficiation What are they…..

REE Beneficiation How rare are they…..

U.S. Geological Survey Fact Sheet 087-02

cerium is the 25th most abundant element at 68 parts per million, more abundant than copper

REE Beneficiation Where do we find them…..

Karin Soldenhof – Ansto Minerals – ALTA 2013

REE Beneficiation Largest deposit…..

Rare Earth Element deposits – GSSA 2011 – Jock Harmer

Bayan Obo, China (Inner Mongolia) 48 Mt contained REO

China’s Rare Earth Elements Industry: What can the West learn? IAGS 2010

REE Beneficiation China syndrome...

• China possesses 40% of global REE reserves

• China Produces >80% of Global REE

In July 2010 Chinese Ministry of Commerce reduces REE export quotas

= REE prices increase of over 1500% in space of a few months!

In July 2013 Chinese Ministry of Commerce relaxes REE export quotas

= REE prices tumbled to pre-2010 levels in space of a few months!

• Rare earths – strategic elements

• Total dominance of China as a producer => alternative sources of

supply

• Two new world class REE refineries – Lynas and Molycorp

• Non-Chinese production - a strategic rather than cheaper alternative

REE Beneficiation Outside of China?…..

Rare Earth Element deposits – GSSA 2011 – Jock Harmer

Mountain Pass, USA Mount Weld, Australia

1.4 - 2 Mt contained REO 1.78 – 4.2 Mt contained REO

REE Beneficiation South Africa ?…..

Phosphogypsum waste dumps

LnPO4∙nH2O), (NaLn(SO4)2∙H2O


Monazite – Namaqua Sands and Richards Bay

(Ce, La, Pr, Nd, Th, Y)PO4


Monazite-apatite-quartz - Steenkampskraal

(Ca, REE)PO4(F,Cl,OH)x

(REE, Th)PO4


Carbonatite - Zandkopsdrift

Ca5(PO4)3(F,Cl,OH)

CaAl3(PO4)2(OH)5•(H2O)

LnPO4

(Ce,Ca,Th)(P,Si)O4


Pegmatite - Naboomspruit

REE Beneficiation What minerals?…..

REE mineral Formula

Bastnäsite LnCO3F

Monazite (Ln, Th)PO4

Xenotime YPO4

Minerals of major economic significance

Parisite

Synchisite

Allanite

Apatite

Britholite

(Ln)2Ca(CO3)3F

Ln Ca(CO3)2F

(Ce, Ca, Y)2 (Al, Fe)3 (SiO4)3 (OH)

Ca5(PO4,CO3)3(OH,F) (Ln, Ca) (SiO4, PO4)3(OH, F)

REE Beneficiation What is the targeted product…..

Mining/ concentration

RE Mineral concentrate

RE Chemical concentrate

Ref

ine

ry

La

Ce

Pr

Nd

Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

Tm

Yb

Lu

Y

Metal/Alloy production

Speciality applications

Increasing value

REE Beneficiation High level processing route…..

Cracking of ore matrix

Solubilizing/leaching of REE

Solid/Liquid separation

Recovery purification

REE Beneficiation How rare are they…..

So “Rare Earth Elements” are not all that rare ! “…but their extraction as pure elements requires a higher technology than the winning of gold.” Mariano (1989)

REE Beneficiation How difficult to process?…..

Buzzle.com

REE Beneficiation Why are they so difficult to process…..

Ore Type 1

Ore Type 2

Ore Type 3

Ore Type 1: Complex monazite ore, REE mineralised

as phosphates: (La,Ce,Nd,Th)PO4 , YPO4

Ore Type 2: Complex bastnaesite ore, REE

mineralised as Fluoro-carbonates: (Ce,La)(CO3)F

Ore Type 3: Complex synchysite ore,

REE mineralised as Ca-fluoro-

carbonates: Ca(Ce,La)(CO3)2F

Complex mineralogy and/or low REE grade

• Difficulties in conventional physical upgrading of REE bearing minerals

Phosphogypsum: Very low grade, REE

hardly soluble phosphates and double

sulphates: LnPO4∙nH2O,

NaLn(SO4)2∙H2O

Phosphogypsum


e-

e-

e-

e-

[Xe] 4fn-15d16s2

or

[Xe] 4fn6s2

[Xe] 4fn-16s2


#1 Chemistry of the Rare Earth elements are determined by their ionic radii

#2 Chemistry of the Rare Earth elements are determined by their valence state

Almost exclusively +3


Similar ionic radius + Same valence

state = Same chemical behaviour

………………..(2)

Same chemical behaviour ≈ Difficult inter-element

separation ………………..(3)

Number of f – orbital electrons + Nature of f -orbitals = Unique chemical

behaviour ………………..(1)

Unique chemical behaviour

• unusual spectroscopic properties due to shielding of the 4f orbitals by the filled 5s2 and 5p6 sub-shells

• large number of unpaired magnetic moments

• high magnetic anisotropy

• high coordination numbers

REE Beneficiation How do we separate them from one another?…..

Nature provides some assistance!

#1

Light REE Middle REE Heavy REE

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu


#2

III IV II III

#3


Electronegativity


R P

O

R O

OH

PC88A

[RE3+]aq + 3[(HA)2]org↔ [RE(HA2)3]org + 3[H+]aq

Aqueous phase

Organic phase

REE3+

aq

REE3+ org

Extractability

Equilibrium pH


Separation scheme – using pH and redox

#1 ppt REE as hydroxide

REE leach liquor

#2 Oxidative drying

#3 Redissolution

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

La Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

#4 pH controlled SX La Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

#5 pH controlled SX La Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

#6 SX/IX La Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu


Lanthanide solution Filter

SX Mixer

SX Mixer

SX Mixer

SX Loading

SX Loading

SX Loading

SX stripping

SX stripping

SX stripping

La-Nd-Pr-Sm-Eu-Gd

solution Sm-Eu-Gd solution

Sm-Eu-Gd

solution

Eu – redox

separation

Eu purification SX Loading

SX Loading

SX Loading

SX stripping

SX stripping

SX stripping

SX Sm-Gd

separation

precipitate, filter

calcine

Eu2O3

precipitate, filter

calcine

Sm2O3

Sm solution

precipitate, filter

calcine

Gd2O3

SX Mixer

SX Mixer

SX Mixer

SX Mixer

SX Mixer

SX Mixer

SX Loading

SX Loading

SX Loading

SX stripping

SX stripping

SX stripping

SX La-Nd-Pr

separation

SX Mixer

SX Mixer

SX Mixer

SX Loading

SX Loading

SX Loading

SX stripping

SX stripping

SX stripping

SX Nd-Pr

separation

La-Nd-Pr

solution

La-Ln concentrate

La(NO3)3

precipitate, filter

calcine

Pr2O3

precipitate, filter

calcine

Nd2O3

REE Beneficiation Can it be done in South Africa?...

REE processing plants and refineries in particular:

• complex,

• capital-intensive =>

• in order to be globally competitive => an economy of scale in the region of ≥20,000 tpa TREO production

Refinery Molycorp

Mountain Pass (USA) Lynas

Mount Weld (Australia)

Size, t/a 19,500 – 40,000 22,000

Products All All Cost $ 531 000 000 $AUS 478 000 000

Size and investment for building a REE refinery

Problem Statement #1

REE Beneficiation What does it cost?…..

Citizen Journalists Malaysia

Capacity – 22 000 t REO/a

CAPEX – $ 478 000 000

REE Beneficiation Can we do this in South Africa?...


Mine or Prospect Name REO, mLn

t Ore reserves,

mLn t Grade REO, %

Mountain Pass, USA 1.8 13.59 8.2

Mount Weld, Australia 1.7 17.49 8.1

Kangankunde, Malawi 0.12 2.53 4.9

Steenkampskraal, South Africa 0.03 0.25 17

Zandkopsdrift, South Africa 0.53 22.92 2.32

Glenover, South Africa 0.013 1.64 0.8

Loftdal, Namibia 0.12 9.6 1.2

Mount Muambe, Mozambique 0.015 1.6 0.94

Songwe, Malawi 0.065 4.4 1.47

Tantalus, Madagascar 0.09 2.9 3.08

Wigu Hill, Tanzania 0.07 3.3 2.17

Nolans Bore, Australia 0.85 30.3 2.8

Holidas Lake, Canada 0.057 2.85 2.0

Kvanefjeld, Greenland 4.91 457 1.1

Nechalacho, Canada 0.9 57.49 1.56

REE Beneficiation Can we do this in South Africa?...

Problem Statement #3 Complex technology

REE Beneficiation Centralized refinery

Deposit 1

Deposit 2

Deposit 3

Deposit 4

Physical

Concentrate 1

Physical

Concentrate 2

Physical

Concentrate 3

Physical

Concentrate 4

Processing

Option 1

Processing

Option 2

Processing

Option 3

Processing

Option 4

Chemical REE

Concentrate 1

Chemical REE

Concentrate 2

Chemical REE

Concentrate 3

Chemical REE

Concentrate 4

R

E

F

I

N

E

R

y

La

Ce

Pr

Nd

Sm

Eu

Gd

Tb

Dy

Ho

Y

Er

Tm

Lu

On siteCentralized facility

Variable concentrates Economy of scale Infrastructure

Chemical supply Established area Transportation …




•Centralized => dependent on feed => planning of the feed supply is critical => know your feed before process parameters generation

•Secure off-take agreements:

REE prices - volatile

Difficult to market

•Project development & execution - equity-financed by the key partners or through a strategic national investment

•Transport, disposal and storage of radioactive waste

Critical issues to be addressed


• Economies of scale => costs of reagents & processing;

• Developed infrastructure => sophisticated operational

support;

• Access to reagent production & recycling facilities;

• Qualified staff <= well-established area;

• Centralized storage facility for wastes.

Benefits of a centralised facility

REE Beneficiation Process technology…


Late 60s to late 70s

Development

work in REE

analytical and

mineralogical

methods to be

used for clients

• R&D test work on

separation of REE

• Project on phosphogypsum

sludge (Phalaborwa) for

leaching and separation of

certain targeted REE

• From bench-scale to pilot-

plant scale followed by

demo plant for production of

tonnes of mixed REO

• Including the design of REE

plants and cost estimates

Late 80s to late 90s

More R&D

test work on

REE

(synergistic

systems)

Late 90s to early 2000

Marubeni enquiry

on evaluation of

phosphogypsum

dumps

(Phalaborwa) for

REE recovery

2009 2010 onward

R&D test work on REE

restarted and on-going to

develop flow sheets for

REE recovery, impurity

removal from REE

solutions and separation

of targeted REE

Montero, Marubeni and

other commercial

projects on REE recovery

and separations started

and on-going

REE Beneficiation Process technology…


REE Beneficiation Can South Africa build and operate a centralized REE facility?

Technical expertise to develop a robust flow sheet and supply wide ranging technical

support once operation is running

Governmental support

Infrastructural support

Wastes and radioactive materials storage

South Africa may not have world class REE resources

There is probably space for one more world class producer in the next 10 years

THE QUESTION IS: WHY NOT SOUTH AFRICA?

37

Thank You

www.mintek.co.za

Documents

REE Processing | A South African perspective · REE Beneficiation How rare are they….. U.S. Geological Survey Fact Sheet 087-02 cerium is the 25th most abundant element at 68 parts