Hydrometallurgical separation methods

(1)

Introduction to hydrometallurgical separation

methods

Sami Virolainen

BJ90A1000 LUONNONVARAT JA NIIDEN PROSESSOINTI KEMIAN- JA

ENERGIATEOLLISUUDESSA

27.3.2012 klo 12.15-13.45

Sami Virolainen

Hydrometallurgical separation methods

q

Selective leaching

q

Selective precipitation

q

Ion exchange

(2)

Selective precipitation

25.11.2010 Sami Virolainen

Sulphide precipitation

2+

2-M +S

MS(s)

2+ +

M +HS

MS(s)+H

Hydroxide precipitation

2+ -2

M +2OH

M(OH) (s)

(“Sulfide versus hydroxide precipitation - BioMineWiki,” 2010) Talvivaaran kaivoshanke, Kainulainen, 2006

Ion exchange: Basic consepts

Distribution coefficient/factor

Separation factor

–Experimental value, depends

on total concentration of solution and temperature

Selectivity coefficient

– For theoretical purposes

(Helfferich, 1962)

i

,

where is concentration of

component i in resin phase

i i i

q

D

c

q

=

A B A B A B A B B A B A B A

m m

c c

x x

m m

c c

x x

α ≡

=

A B B _A B _A B _A A B A B A B z z z z z z A B A B A B z z z z z z B A B A B A

m

c

x

K

m

c

x

≡

=

(3)

Ion exchange: materials

Zeolites

(Alumosilicates)

Minerals

Synthetic

• Mostly cation exchangers

• Chabazite, (Ca,Na)[Si

2

AlO

6

]

2.

6H

2

O

• Harmotome, (K,Ba)[Si

5

Al

2

O

14

]

2.

5H

2

O

• Montmorillonite, Al

2

[Si

4

O

10

(OH)

2

]

.

nH

2

O

(“Chabazite-Ca Image,” 2010)

• Mostly molecular sieves

(“NASA Quest > Space Team Online,” 2010)

(“Rock, limestone and clay - Zeolite - Te Ara Encyclopedia of New Zealand,” 2010)

Ion exchange: materials

Ion exchange resins

(“INDIAN ION - Resins,” 2010)

• Frameworks:

§

PS-DVB

§

Acrylic

§

Silica

• Functionalities:

§

Strong cation exchanger

§

Weak cation exchanger

§

Weak anion exchanger

§

Strong anion exchanger

(4)

Ion exchange: resins

Strong cation exchanger

Applicability

Food processing

Mg, Ca

Weak cation exchanger

AMBERLITE FPC22 H :

•PS-DVB framework

•Sulfonic acid functionality

AMBERLITE IRC86 :

•Polyacryl framework

•Carboxylic acid functionality

Ion exchange: resins

Amberjet 4200Cl:

•PS-DVB framework

•Quaternary ammonium functionality

Applicability

Weak anion exchanger

Strong anion exchanger

Chelating resin

WP-1:

•Silica framework

•Polyethylene imine functionality

Lewatit TP-260:

•PS-DVB framework

(5)

Ion exchange: operation - columns

(Hiltunen, 2010)

(“Water softeners,” 2010) (“Ion-Exchange Demineralisation Plants,” 2010)

Operation usually in 4-5 stages:

1. Loading

2. Wash

3. Elution

4. Wash

5. (Regeneration)

Possibility of continuous operation –

SMB

(Simulated moving bed)

Solvent extraction: history

First law about metal distribution between two immiscible phases 1872

(Berthelot and Jungfleisch)

First industrial scale operations in 1940’

s: Recovery of radioactive materials,

(6)

Solvent extraction: Basic consepts

Extraction coefficient

Separation factor between metals i and j

pH

0.5

–If extraction is dependant on pH, pH when

E

is 0.5

0 i,org i,aq i,aq i i,aq i,aq i,org i,aq 0 i,aq

is concentration of the metal in organic phase

is concentration of the metal in aqueous phase

is initial concentration of the metal in aqueous phase

c

E

c

−

=

i i/j j

E

SF

E

=

(“PUREX process,” 2010)

Solvent extraction: Types of extraction systems

According to (Ritcey, 2006)

Compound formation

–Acidic and/or chelating extractants extract metal cations

(Cation exchange)

Ion association

–Amine extractants extract ion pairs or anionic complexes

(Anion exchange)

Solvation

– Oxygen containing extractants make metal compelexes or inorganic

molecules more soluble to organic phase

M

n

HA

MA

H

n

+

₊

+ + -3 3 + - - + - -3 3

R N+HX

R NH

X

R NH

X +MY

R NH

MY +X

⋅

UO (NO ) +2TBP

UO (NO )

⋅

2TBP

(7)

Solvent extraction: reagents

Phosphoric acid derivatives

Carboxylic acids

Acidic extractants

Di-2-ethylhexylphosphoric acid

(D2EHPA, P-204, etc.)

Commercial uses

Zn, In

Selective Co/Ni –separation

Cu, Co, Ni, Fe

Bis(2,2,4-trimethylpentyl)phosphinic acid

(Cyanex 272, Ionquest 290)

Branched C-10 carboxylic acid

(Versatic 10)

Solvent extraction: reagents

Chelating extractants

Hydroxyoximes

(Acorga M5640, LIX-984, etc.)

Commercial uses

Cu

U, V, W, Mo

U, Cd, Co, Zn, Rare earths

Trioctylamine

(TOA, Alamine 308)

Quaternary ammonium salt

(Aliquat 336)

Amine extractants

X = H, (Cl)

Y = H, CH

3

(8)

Solvent extraction: reagents

Phosphoric acid derivatives

Solvating extractants

Tributylphosphate

(TBP)

Commercial uses

U, Rare earths

Selective Co/Ni –separation, U

Trioctylphosphine oxide

(TOPO, Cyanex 921)

Solvent extraction: typical flowsheet

(9)

Solvent extraction: equipment

Mixer-Settler

(“KCCL - Site Photos,” 2010) (“solvent extraction in precious metal refining,” 2010)