pirometalurgia del cobre
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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) .
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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
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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)
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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
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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
-
Que reacciones ocurren durante el proceso?
-
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
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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
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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)
e.g. Smelting Flash Furnace
complex reactor with many zones
Slag Cu2O+FeO+SiO2
Matte or liquid Cu metal
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
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Que reacciones ocurren durante el proceso?
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,
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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
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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
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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
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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
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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
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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
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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
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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?
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?
-
14/03/2015 47
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
-
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
top related