pirometalurgia del cobre

Curso Pirometalurgia 2015 (Primer semestre)

Evaluacin del curso Peso

Acadmica

1-Tutoriales total=7, valor de cada tutorial, siete tutoriales 2 puntos

cada uno

14

2-Balances de masa y energa (reporte) 16

3-Lectura, reporte y presentacin de un documento (cinco minutos de

presentacin)

15

4-Construccin de diagramas de fases usando simulacin (trabajo en

grupo)

10

5-Examen final 25

Total 80

Laboratorios

Reportes de laboratorio 20

Puntajes mnimos para aprobar el curso (el estudiante deber aprobar ambos

componentes del curso, de otra forma ser reprobado)

Acadmica 44

Laboratorios 11

La asistencia es obligatoria par los laboratorios

Asistencia a la clase acadmica mayor al 90 % incrementara la nota incluso de 52

a 55 puntos (Nota: La nota no incrementara en otros casos) .

Al2O3

ZINCSmelting

LEADSmelting

NickelSmelting

CopperSmelting

COALASHES

Fe-Mnalloys

S

MgO

Cu2O

Mn-O

PbO

ZnO

K2O

Na2ONiO

Cr-O

Sn-O

Fe-Cralloys

Fe-Nialloys

FeO|

Fe2O3

|

SiO2

CaO

S

The basic system

4Source materials: copper sulphide minerals

Cu2S: Chalcocite

Cu, Fe and S are chemically bound

CuS : Covellite

Minor elements: Valuable: Au, Ag, Ni

Unwanted: As, Sb, Bi

Cu5FeS4:Bornite

CuFeS2: Chalcopyrite

Cu12As4S13 : Tennantite

FeS2: Pyrite

FeAsS : Arsenopyrite

(Fe, Ni)9S8, : Pentlandite

SiO2: Quartz

Minor components:

Al2O3, MgO, CaO

Principal Other

5Basic Reactions in Cu production

Process aims:

Metal production (Cu, Au, Ag, Ni, PGM......

Metal purification (S, O, As, Zn, Pb )

Recycling (Au, Ag)

CuFeS2

1) removal of S into gas S+O2 SO2 (gas)

2) oxidation of FeS FeO / Fe3O4

then fluxing of FeO / Fe3O4 with SiO2 slag

3) conversion of Cu2S Cu (liquid)

6Process Air

Oxygen

Fuel

Molten

Bath

Feed Mix

Offgas

Offgas

System

Molten

Products

Steps in Cu

productionConcentrate with

20-30wt% of Cu

Matte 45-

70wt% Cu

Blister copper

99% Cu

Cu anodes

0.002%S and 0.15%O

Cleaning

-Electric Furnace

-Flotation

Smelting

Converting

Refining

Slag

1-3 % Cu

Slag

7FeS

H2O

SiO2 Al2O3

Cu2S

CONCENTRATE

CuS

SO2O2

N2

GASESH2O

Heat

AIR

(O2 , N2)

Flux

(SiO2 )

OXYGEN

Cu production schematic

Slag Cu2O-FeO-SiO2

Matte Cu2S-FeS

O2 SO2

Flux

(SiO2 )

White metal Cu2S (l)Anode Cu

O2

Slag Cu2O-FeO-SiO2SO2

4.

CLEANING

Blister

Cu-S-O

1%S, 0.1%O

1. SMELTING

2. COVERTING3. REFINING-2stages

1- %O=0.7%, %S=0.02

2-%O=0.15, %S=0.02

CO/H2O

CH4 O2

SO2

12

Que informacin requerimos para describir el proceso?

Que reacciones ocurren durante el proceso?

Como representar esta informacin en forma matemtica?

Como representar la informacin en forma grafica?

Como obtener la informacin necesaria para determinar los parmetros de la formulacin

matemtica? Cual es la confiabilidad y que tan precisa es la informacin?

Cuales son los rangos de temperatura y composicin donde las fases se encuentran en

estado solido, liquido o gaseoso?, Porque se presenta la separacin de fases?

Como sistematizar la informacin relacionada a las reacciones quimicas?

Cuales son los mecanismos en la cintica de las reaccione?

Cual es el objetivo de obtener y sistematizar esta informacin?

1-Curiosidad o satisfaccin de entender con mayor profundidad los procesos de

produccin pirometalurgica de metales

2-Posibilidad de tomar decisiones durante la operacin industrial en una forma

analtica (basado en principios qumicos) contrario a la toma de decisions por

ensayo y error (basado solo en la experiencia)

3-Posibilidad de mejorar (optimizar) los procesos existentes

4-Posibilidad de modificar los procesos existentes para procesar concentrados o

material de reciclaje con nuevas caractersticas.

5-Posibilidad de desarrollar nuevos procesos

14/03/2015 11

Smelting

furnace

Feed 100 t/h, CuFeS2

Coal

Flux (SiO2)

O2+air

(50%O2 enrichment)

Mechanical dust (4.5%)

Gas

Slag (Fe/SiO2 = 1.6-2.0)

Matte 60 wt % Cu

Heat loss 11.1MW

Input is optimised

to get output

specifications

Heat balance and chemical partitioning

14/03/2015 12

Reaction

Shaft

Slag Cu2O+FeO+SiO2

Matte or liquid Cu metal

Uptake

Shaft

Settler

SO2 + N2

CuFeS2

FeAsS

SiO2FeS

Cu2S

FeS2

Cu2SO4

Cu2S FeS

Fe3O4

Fe3O4Cu2SO4

Gas/liquid & gas/solid

reaction mechanisms

in reaction shaftO2 + N2

Slag

Matte

Cu2S

Fe3O4

SiO2

SiO2CuFeS2

FeS

Liquid/liquid and

liquid/solid reaction

mechanisms in settler

SO2

Matte

M

Slag

Matte

Decantation

and liquid/liquid

reactions

Fe3O4Cu2SO4

SiO2

Dust

carry-over

e.g. Smelting Flash Furnace

complex reactor with many zones

14/03/2015 13

Reaction

Shaft

2CuFeS2(concentrate) + (4-1y)O2(g) + xSiO2(s)

{Cu2S+yFeS(l,matte)} + {(2-y)FeO+xSiO2(l,slag)} + (3-

y)SO2(g)



Slag Cu2O+FeO+SiO2


Uptake

Settler

CuFeS2 +SiO2+ O2 + N2SO2 + N2

I. Flash zone

O2,gas + S SO2, gas

O2gas Ocondencede.g. 1 O2+2FeFe2O3 liq/solid

SO2 + O2+CuCuSO4 liq/solid

II. Settler under and close to flash zone

Fe2O3 liq/solid + S SO2, gas + 2FeO

CuSO4 + 4S 2SO2, gas + Cu2SIII. Settler far from flash zone

Matte drops settling


FeS(l)+Cu2O(l)=Cu2S(l)+FeO(l).(1)

FeS(l)+3/2O2=FeO(l)+SO2 (g).(2)

1/2S2 (g)+O2 (g)=SO2 (g)(3)

Cu2S(l)+3/2O2(g)=Cu2O(l)+SO2(g)(4)

FeS(l)+3Fe3O4(s)=10FeO(l)+SO2 (g).(5)

3FeO(l)+1/2O2=Fe3O4 (s)(6)

2Cu(l)+1/2O2=Cu2O(l)............(7)

SO2 (g)=[S]+2[O].(8)

PbS(l)+3/2O2 (g)=PbO(l)+SO2 (g)..(9)

ZnS(l)+3/2O2 (g)=ZnO(l)+SO2 (g)(10)

Pb(l)+SO2(g)=PbS(l)+O2 (g).(11)

Metalic elements:

Cu, Fe, Pb, Zn

No metals:

O, S

Minor components:

CaO, Al2O3, MgO, Cr2O3

Other minor elements:

Au, Ag, Mo, Ni,.As, Sb, Bi,

Representacin grafica de las ecuaciones de

equilibrio qumico

Diagramas de predominancia

16

Use of predominance diagrams to analyse conditions for metal

stability

Fe(metal) + 0.5O2 = FeO(slag) Keq1=aFeO/(aFe*P0.5

O2)

Fe(metal) + 0.5S2 = FeS(matte) Keq2=aFeS/(aFe*P0.5

S2)

FeS(matte)+0.5O2=FeO(slag)+0.5S2 Keq3=aFeO*P0.5

S2/(aFeS*P0.5

O2)

Using 0 = Gro + RTln Keq at a fixed temperature

the relative stabilities of these the condensed phases Fe, FeO and

FeS can be described on predominance diagrams PS2 and PO2.

Thermodynamics of copper smelting and converting

O2 eq FeO Felog P 2 log K 2 log a / a

S 2 eq FeS Felog P 2 log K 2 log a / a

O2 S 2 eq FeO FeSlog P log P 2 log K 2 log a / a

Calculation of PSO2

FeS(matte) + 3/2O2(g) = FeO(slag) + SO2(g)

G0=-RTlnK

K=( 2)/( 21.5)

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

Tridymite p.p.f

Spinel p.p.f.

Fe metal

Cristobalite p.p.f

Wustite p.p.f.

FeO Fe2O3

SiO2

0.20.40.50.60.70.8

0.9

0.8

0.7

0.6

0.5

0.4

0.2

0.1

Fe3O4

18

Cu-Fe- S-O predominance diagram 1300oC

Cu

Cu2O

Fe3O4

FeS

Fe

Phase Field Boundaries

Equilibria Reactions Equilibrium constant

Matte-

-slag

p-q

FeS (l) +

1/2O2(g)

= FeO (l)

+1/2 S2(g)

S FeO

eq

O FeS

P aK

P a

1/2

2

1/2

2

Matte-

-gas

t-p

1/2S2+O2=SO2 SO

eq

O S

PK

P P 2

1/2

2 2

Matte -

blister r-s

Cu2Sliq =

2Cublister + xSblister

+ (1-x)S2

x x

Cu blister S blister S

eq

Cu S

a a PK

a

2 (1 )/2

, , 2

2

Slag-

-Fe metal

r-q

Fe+O2=FeO

Slag-

-solid

magnetite

s-t

FeOslag + O2 =

Fe3O4solid

19

Sulphur-Oxygen potential Diagram for the

System Cu-Fe-S-O-SiO2 at 13000C

0.5

Converter

conditionFlash Furnace

condition

Settler

Condition

Electric furnace

Flash Smelting:

3 stages in 1 process

1. oxidising smelting

- open system

2. reducing settling

- closed system

3. Settling

Como obtener los parmetros de las ecuaciones qumicas?

Experimentos

o

(Calculaciones basadas en termodinamica estadistica)

Como obtener los parametros de las ecuaciones quimicas?

At a fixed temperature

Fe(s,l) + 0.5O2 (gas)= FeO(s) Keq1=aFeO/(aFe*P0.5

O2)

Si conocemos Keq1,

Fe(s, l) + 0.5O2 (gas)= FeO(FeO-SiO2 liquid solution)

aFeO=aFe*P0.5

O2*Keq1

Cuales son los rangos de temperatura y composicin

donde las fases se encuentran en estado solido, liquido

o gaseoso?,

Diagramas de fases

23

Phase Diagrams are constructed to represent

Ranges of conditions of stability of various phase assemblages

Phase boundaries

Sequence of equilibrium transformations as a function of system parameters

Phases in equilibrium

Proportions of phases

and much more

24

Phase - FeO-Fe2O3Important Concepts:

1. Phase vs Chemical Species

2. Compound vs Component

3.Solution phase, purecompound,stoichiometric phase,binary compound

4. Bulk composition vs phasecomposition

5. Proportions (amounts) ofphases vs compositionsof phases

6. Phase fields (single phasefield, two-phase field

7. Lever rule /mass balance

8. Crystallisation path

9. Liquidus, solidus

10. Primary phase fields

11. Phase rule

12. Congruently vsincongruently meltingcompound

13. Eutectic, peritectic

25

Phase Relations in FeO-Fe2O3-SiO2

mass fraction

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

Tridymite p.p.f

Spinel p.p.f.

Fayalite

Fe

met

al

Hem

ati

te

2 LiquidsCristobalite p.p.f

1473

15231573

1623

1673 172

3

1773

1823

187

3

192

3

Wustite p.p.f.

FeO Fe2O3

SiO2

0.20.40.50.60.70.8

0.9

0.8

0.7

0.6

0.5

0.4

0.2

0.1

Fe O3 4

Fe SiO2 4

Liquidus

Isotherms

Ref:E. Jak, P.Hayes, A.D.Pelton, Decterov S., Int. J. of Materials Research (2007), 98(9), 847-854 .

Spinel (Fe3O4)

Como construir los diagramas de fases?

Experimentos

o

Simulacion (basado en datos experimentales)

EXPERIMENTAL APPROACH TO PHASE EQUILIBRIUM DETERMINATION

I. Control of PO2 and PSO2 and T.

II. Small samples suspended on a

substrate

III. Fast quenching to produce a well

quenched glassy slag.

IV. Analysis of matte, glassy slag and

crystals by EPMA

Experimental equipment

Specimen

Pt wire (sample holder)

Gas Inlet

ControllerThermocouple

Watch glass & O-ring seal

Hot zone

Workingthermocouple

Aluminasheath covers Gas outlet

Removable end

Alumina tube

Heating elements

Quenching and

sample preparation

Continuum X-ray

Characteristic X-Ray

Auger Electrons

Incident Electrons

Fluorescent X-ray

Secondary Electrons

Back Scattered

Electrons

High

Vacum

Electron and

X-ray detectors

Sample

1mm

Quantitative composition of the

1mm probe

EPMA quantitative

composition analysis

Methodology

-The compositions of the phases (glass

and solids) are then measured using a

JEOL JXA 8200L (trademark of Japan

Electron Optics Ltd., Tokyo) electron

probe X-ray microanalyzer (EPMA) with

Wavelength Dispersive Detectors

(WDD).

-The phase compositions are measured

with EPMA with accuracy within 1 wt %

or better for Fe, Si and Ca and within 0.1

for Cu.

PO2 of 10-8 atm

1200 0C, Cu saturation

FeOCaO

SiO2

Como construir los diagramas de fases?

simulacin

Ranges of stability for a system using the Gibbs Free Energy of

phases at equilibrium

= FeOFeO + SiO2SiO2

T +FeO,SiO2

2FeO,SiO2

Parameters of equations of Gibbs energy for the system FeO-Fe2O3-SiO2 and results of simulation

33

THERMODYNAMIC MODELLING

FactSage

Computer Package

------------------------------------

GIBBS FREE ENERGY

MINIMISATION SOFTWARE

+

THERMODYNAMIC DATABASES

+

INPUT/OUTPUT WINDOWS - BASED

34

FactSage

THERMODYNAMIC DATABASES

- Over 5000 stoichiometric compounds

- Advanced solution models

- Evaluated complex solutions

-----------------------------------------------

Multi-component Multi-phase Equilibria

/GAS /

/SLAG (molten oxides) /

/ MOLTEN SALTS (Cl, S, SO3, ) /

/METAL ALLOYS /

/SOLIDS /

/AQUEOUS SOLUTIONS/

35

THERMODYNAMIC MODELLING:

FactSage Thermodynamic Databases

developed by PYROSEARCH in collaboration with CRCT:

PbO ZnO CaO FeO Fe2O3 - Al2O3 - SiO2

SiO2 - Al2O3 CaO FeO Fe2O3 -MgO -Na2O -K2O

36

THERMODYNAMIC MODELLING

INPUT: OPERATIONAL PARAMETERS

- COMPOSITION

- TEMPERATURE

- ATMOSPHERE (PO2)

OUTPUT:

- AMOUNTS AND COMPOSITIONS

OF ALL PHASES

FactSage

HOMOGENEOUS

AND

HETEROGENEOUSS

LAG VISCOSITY

MODELS

Algunos diagramas utilizados en la

pirometalurgia del cobre

38

Phase diagram of FeO-FeS-SiO2 Porque se presenta la separacin de fases?

Basic Principle of Matte-Slag separation

In the ternary FeS-FeO-SiO2 system, the addition of silica to a homogeneous FeS-FeO melt tends to separate into matte and slag Similar reaction occur in the presence of Cu

CuFeS2+O2+SiO2=

{Cu-Fe-S}+(FeO-SiO2)+SO2

Slag

FeO:54.8wt%

FeS:17.9wt%

SiO2:27.3wt%

matte

FeO:27.4wt%

FeS:72.4wt%

SiO2:0.16wt%

39

Binary system Cu2S-FeS

wt% FeS

1400

1200

1000

800

600

400

200

Tem

pera

ture

0C

Matte

40

Binary system Cu-Cu2S

DEFINICIONES

Equilibrium:

Informal definition

In all systems there is a tendency to evolve toward states in which the properties are

determined by intrinsic factors and not by previously applied external influences. Such

simple systems states are, by definition, time independent. They are called equilibrium

states.

Formal definition

Particular states of simple systems that, macroscopically, are characterized completely by

the internal energy U, and the mole numbers N1, N2,Nr of the chemical components.Operationally, a system is in an equilibrium state if its properties are consistently described by

thermodynamic theory.

The single, all encompassing problem of thermodynamics is the determination of the equilibrium state that eventually results after the removal of internal constrains in a closed,

composed system (Herbert B. Callen, thermodynamics and an introduction to thermo-

statistics).

Phase field: region of material in the phase diagram that is chemically uniform, physically distinct, and (often) mechanically separable of other phases.

-Single phase field: Only one phase

-Two phase field: Two phases coexist

-Three phases: .

Chemical species: atoms, molecules, molecular fragments, ions, etc., subjected to achemical process or to a measurement.

Chemical compound: chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions.

Chemical component: Element contained in a phase

Solution phase: solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent

Crystallisation path: Sequence of appearance of phases during cooling.

DEFINICIONES

Liquidus: temperature (a curve on a phase diagram) above which a material is completely liquid, and the

maximum temperature at which crystals can co-exist with the melt in thermodynamic equilibrium.

Solidus: temperatures (a curve on a phase diagram) below which a given substance is

completely solid (crystallized) in thermodynamic equilibrium.

Primary phase: The crystal phase that crystallizes first on cooling a substance to its liquidus temperature.

Congruent melting: occurs during melting of a compound when the composition of the liquid that forms is the

same as the composition of the solid.

Incongruent melting: occurs when a substance does not melt uniformly and decomposes into another

substance.

Eutectic reaction: Liquid=Solid 1+ Solid 2+Solid 3+.A liquid react at a fix temperature to yield solid phases

Peritectic reaction: L+Solid 2+Solid 3+ =Solid 1A liquid and solid phase of fixed proportions react at a fixed temperature to yield solid phase.

DEFINICIONES

44

References:

H.G.Lee Chemical Termodynamics for Metals and Materials

Phase Equilibria and Free energies pp.144..156

Binary systems:pp. 166...204

Ternary systems: pp.204..231

D. R. F. West Ternary Equilibrium Diagrams, 1981

Osborne and Muan, Phase equilibria among oxides in steel making 1965

E.Levin, Phase Diagrams for Ceramists, 1964

Akira Yazawa: Thermodynamic considerations of copper smelting, Canadian Metallurgical

Quarterly, Vol. 13, Number 3 (1974)

Akira Yazawa: Extractive Metallurgical Chemistry with Special Reference to Copper Smelting,

28th Congress of IUPAC, Vancouver, August 1981

FIN PRIMERA SESIN

Que informacin requerimos para describir el proceso?


Como representar esta informacin en forma matemtica?

Como representar la informacin en forma grafica?

Como obtener la informacin necesaria para determinar los parmetros de la formulacin

matemtica? Cual es la confiabilidad y que tan precisa es la informacin?

Cuales son los rangos de temperatura y composicin donde las fases se encuentran en estado

solido, liquido o gaseoso?, Porque se presenta la separacin de fases?

Como sistematizar la informacin relacionada a las reacciones quimicas?

Cuales son los mecanismos en la cintica de las reaccione?

14/03/2015 47

Reaction

Shaft

Slag Cu2O+FeO+SiO2


Uptake

Shaft

Settler

SO2 + N2

CuFeS2

FeAsS

SiO2FeS

Cu2S

FeS2

Cu2SO4

Cu2S FeS

Fe3O4

Fe3O4Cu2SO4

Gas/liquid & gas/solid

reaction mechanisms

in reaction shaftO2 + N2

Slag

Matte

Cu2S

Fe3O4

SiO2

SiO2CuFeS2

FeS

Liquid/liquid and

liquid/solid reaction

mechanisms in settler

SO2

Matte

M

Slag

Matte

Decantation

and liquid/liquid

reactions

Fe3O4Cu2SO4

SiO2

Dust

carry-over



Copper mineral processing,

smelting and anodes

production

Copper ore

(0.02-0.05 wt% As)

Electrolyte copper

and sub-products

Tailings of

flotation

Final Gas

Emissions of As

Final Slag

As in

Sulphuric

acid

As in Dust

Water

contamination

with As

Selective flotation,

leaching

or

roasting

As disposal

Leaching?

or

Smelting?

As disposal

Arsenic Weight %

Sulphuric acid 27%

Anode 21%

Slag SCF 49%

Gas emisin 3% (12

tons.As/year)

Total 100%

(400 ton.As/year)

Fe-S-O-(As-Cu-Co-)

El efecto del arsenic en el

Sistema

Lineas de liquidus y fases primarias

C-Volatilizacion selective de arsenico

Tostacion: Volatilizacion del arsenico, oxidacion y captura

como polvos de oxidos de arsenico

pirometalurgia del cobre

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