pirometalurgia del cobre

Curso Pirometalurgia 2015 (Primer semestre) Evaluación del curso Peso Académica 1-Tutoriales total=7, valor de cada tutorial, siete tutoriales 2 puntos 14 cada uno 2-Balances de masa y energía (reporte) 16 3-Lectura, reporte y presentación de un documento (cinco minutos de 15 presentación) 4-Construcción de diagramas de fases usando simulación (trabajo en 10 grupo) 5-Examen final 25 Total 80 Laboratorios Reportes de laboratorio 20 Puntajes mínimos para aprobar el curso (el estudiante deberá aprobar ambos componentes del curso, de otra forma será reprobado) Académica 44 Laboratorios 11 La asistencia es obligatoria par los laboratorios Asistencia a la clase académica mayor al 90 % incrementaría la nota incluso de 52 a 55 puntos (Nota: La nota no incrementaría en otros casos) . The basic system LEAD Smelting ZINC Smelting COAL ASHES Sn-O PbO Cu2O S ZnO FeO CaO | Al2O3 S Fe2O3 MgO K2 O | SiO2 NiO Na O Copper Smelting Nickel Smelting 2 Fe-Mn alloys Mn-O Fe-Ni alloys Cr-O Fe-Cr alloys Source materials: copper sulphide minerals Other Principal CuS : Covellite Cu2S: Chalcocite Cu12As4S13 : Tennantite FeS2: Pyrite FeAsS : Arsenopyrite (Fe, Ni)9S8, … : Pentlandite SiO2: Quartz CuFeS2: Chalcopyrite Cu5FeS4:Bornite Minor components: Al2O3, MgO, CaO… Minor elements: Valuable: Au, Ag, Ni… Unwanted: As, Sb, Bi… 4 Cu, Fe and S are chemically bound Ag. Ag) 1) removal of S into gas S+O2 → SO2 (gas) CuFeS2 2) oxidation of FeS → FeO / Fe3O4 then fluxing of FeO / Fe3O4 with SiO2 → slag 3) conversion of Cu2S → Cu (liquid) 5 . Metal purification (S..Basic Reactions in Cu production Process aims: Metal production (Cu. As. Au. PGM.... Zn. O. Ni.. Pb ) Recycling (Au. Steps in Cu production Process Air Oxygen Fuel Concentrate with 20-30wt% of Cu Offgas System Feed Mix  Offgas Molten Bath Smelting Molten Products Slag 1-3 % Cu Matte 4570wt% Cu  Cleaning -Electric Furnace -Flotation Converting  Blister copper 99% Cu  Slag <1 % Cu Refining Cu anodes 6 0.15%O .002%S and 0. %S=0.15. %S=0.7%.1%O CH4 O2 H2O GASES H2O FeS SiO2 2 O2 N2 Cu2S Anode Cu SO2 SO2 O2 SO2 Slag Cu2O-“FeO”-SiO2 White metal Cu2S (l) O2 4. N2) 1. REFINING-2stages Heat Flux 2.%O=0. COVERTING (SiO2 ) SO2 1 Blister Cu-S-O 1%S.02 2-%O=0. SMELTING OXYGEN CuS Flux (SiO2 ) Slag Cu2O-“FeO”-SiO2 1.02 CO/H2O Matte Cu2S-FeS Al2O3 CONCENTRATE 3. 7 CLEANING . 0.Cu production schematic AIR (O2 . liquido o gaseoso?.¿Que información requerimos para describir el proceso? ¿ Que reacciones ocurren durante el proceso? ¿ Como representar esta información en forma matemática? ¿ Como representar la información en forma grafica? ¿ Como obtener la información necesaria para determinar los parámetros de la formulación matemática? ¿ Cual es la confiabilidad y que tan precisa es la información? ¿ Cuales son los rangos de temperatura y composición donde las fases se encuentran en estado solido. ¿ Porque se presenta la separación de fases? ¿ Como sistematizar la información relacionada a las reacciones quimicas? ¿ Cuales son los mecanismos en la cinética de las reaccione? . ¿ Cual es el objetivo de obtener y sistematizar esta información? 1-Curiosidad o satisfacción de entender con mayor profundidad los procesos de producción pirometalurgica de metales 2-Posibilidad de tomar decisiones durante la operación industrial en una forma analítica (basado en principios químicos) 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 características. 5-Posibilidad de desarrollar nuevos procesos . ¿Que reacciones ocurren durante el proceso? . 6-2. CuFeS2 Coal Flux (SiO2) O2+air (50%O2 enrichment) Gas Smelting furnace Slag (Fe/SiO2 = 1.0) Matte 60 wt % Cu Heat loss 11.1MW Input is optimised to get output specifications 14/03/2015 11 .5%) Feed 100 t/h.Heat balance and chemical partitioning Mechanical dust (4. g.e. Smelting Flash Furnace – complex reactor with many zones Gas/liquid & gas/solid reaction mechanisms in reaction shaft Dust carry-over O2 + N2 SiO2 Fe3O4 Cu2S FeS2 SiO2 CuFeS2 FeS Reaction Shaft Uptake Shaft Fe3O4 Cu2S Cu2SO4 Cu2S FeS Fe3O4 SO2 SiO2 CuFeS2 Cu2SO4 FeAsS Cu2SO4 SiO2 SO2 + N2 Settler Slag “Cu2O”+“FeO”+SiO2 Slag Matte or liquid Cu metal FeS Matte Fe3O4 Liquid/liquid and liquid/solid reaction mechanisms in settler Slag Matte 14/03/2015 M Matte Decantation and liquid/liquid 12 reactions . Settler under and close to flash zone Fe2O3 liq/solid + ½ S → ½ SO2.e. gas↑ + ½Cu2S 13 III.slag)} + (3y)SO2(g) SO2 + N2 CuFeS2 +SiO2+ O2 + N2 I.14/03/2015 Settler far from flash zone Matte drops settling . gas↑ ½ O2gas → Ocondenced e. Flash zone O2.gas + S → SO2.g. Smelting Flash Furnace – complex reactor with many zones 2CuFeS2(concentrate) + (4-1½y)O2(g) + xSiO2(s)→ → {Cu2S+yFeS(l.matte)} + {(2-y)FeO+xSiO2(l. gas↑ + 2FeO CuSO4 + 4S → 2SO2.g. 1½ O2+2Fe→Fe2O3 liq/solid ↓ SO2 + O2+Cu→CuSO4 liq/solid ↓ Reaction Shaft Uptake Settler Slag “Cu2O”+“FeO”+SiO2 Matte or liquid Cu metal II. . Ni.(9) ZnS(l)+3/2O2 (g)=ZnO(l)+SO2 (g)…………………(10) Pb(l)+SO2(g)=PbS(l)+O2 (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)……………………….(8) PbS(l)+3/2O2 (g)=PbO(l)+SO2 (g)…………………. Pb. As..(11) Metalic elements: Cu.. Ag.(1) FeS(l)+3/2O2=FeO(l)+SO2 (g)………………………….. MgO... S Minor components: CaO. Bi.….(7) SO2 (g)=[S]+2[O]…………………………………………….. Cr2O3 Other minor elements: Au...… . Fe. Zn No metals: O.¿ Que reacciones ocurren durante el proceso? FeS(l)+Cu2O(l)=Cu2S(l)+FeO(l)………………………. Mo.. Al2O3.. Sb. Representación grafica de las ecuaciones de equilibrio químico Diagramas de predominancia . 5O2 = FeO(slag) Keq1=aFeO/(aFe*P0.5S2 Keq3=aFeO*P0.Thermodynamics of copper smelting and converting Use of predominance diagrams to analyse conditions for metal stability Fe(metal) + 0. 16 .5S2) log PS 2  2 log K eq  2 log aFeS / aFe FeS(matte)+0.5O2) log PO 2  2 log K eq  2 log aFeO / a Fe Fe(metal) + 0.5S2 = FeS(matte) Keq2=aFeS/(aFe*P0.5O2) log PO 2  log PS 2  2 log K eq  2 log aFeO / a FeS Using 0 = Gro + RTln Keq at a fixed temperature the relative stabilities of these the condensed phases Fe.5S2/(aFeS*P0. FeO and FeS can be described on predominance diagrams PS2 and PO2.5O2=FeO(slag)+0. p.6 0.2 .p.f.5 Cristobalite p.2 0.f 0.5) α𝑭𝒆𝑺 𝒊𝒏 𝑪𝒖 − 𝑭𝒆 − 𝑺 𝒂𝒕 𝟏𝟑𝟎𝟎 𝟎𝑪 FeO Spinel p. 0.0.f.f 0.1 Fe metal G0=-RTlnK K=(α𝐹𝑒𝑂 × 𝑃𝑆𝑂2)/(α𝐹𝑒𝑆 × 𝑃𝑂2 1.4 Fe3O4 0.7 0.p.5 𝒂𝒕 𝟏𝟑𝟎𝟎 𝟎𝑪 0.4 Tridymite p.8 0.p. FeS(matte) + 3/2O2(g) = FeO(slag) + SO2(g) 0.6 α𝑭𝒆𝑶 𝒊𝒏 𝑭𝒆𝑶 − 𝑭𝒆𝟐𝑶𝟑 − 𝑺𝒊𝑶𝟐 0. Wustite p.5 0.6 Calculation of PSO2 0. Cu-Fe.blister PS 2 aCu 2 S .blister a S .S-O predominance diagram 1300oC Phase Field Boundaries Cu2O Equilibria Matte-slag p-q Fe3O4 Cu Matte-gas t-p Matte – blister r-s FeS Fe Slag-Fe metal r-q Slag-solid magnetite s-t Reactions Equilibrium constant FeS (l) + PS1/22 aFeO K eq  1/ 2 1/2O2(g) PO 2 aFeS = FeO (l) +1/2 S2(g) 1/2S2+O2=SO2 PSO 2 K eq  PO 2 PS1/22 Cu2Sliq = 2Cublister + xSblister + ½(1-x)S2 Fe+O2=FeO K eq  FeOslag + O2 = Fe3O4solid 18 2 x (1 x )/ 2 aCu . closed system 3. Settling 19 .Sulphur-Oxygen potential Diagram for the System Cu-Fe-S-O-SiO2 at 13000C Flash Smelting: 3 stages in 1 process Converter condition Flash Furnace condition 0.5 1. reducing – settling .open system Settler Condition Electric furnace 2. oxidising – smelting . ¿Como obtener los parámetros de las ecuaciones químicas? Experimentos o (Calculaciones basadas en termodinamica estadistica) . 5O2*Keq1 .5O2 (gas)= FeO(FeO-SiO2 liquid solution) aFeO=aFe*P0. l) + 0.5O2 (gas)= FeO(s) Keq1=aFeO/(aFe*P0.¿Como obtener los parametros de las ecuaciones quimicas? At a fixed temperature Fe(s.l) + 0.5O2) Si conocemos Keq1. Fe(s. liquido o gaseoso?.¿ Cuales son los rangos de temperatura y composición donde las fases se encuentran en estado solido.  Diagramas de fases . 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 … 23 . pure compound.FeO-Fe2O3 24 . Primary phase fields 11. Phase vs Chemical Species 2. solidus 10. Liquidus. Compound vs Component 3. peritectic Phase .Solution phase. stoichiometric phase. Important Concepts: 1. Phase fields (single phase field. Eutectic. Crystallisation path 9. Congruently vs incongruently melting compound 13. Lever rule /mass balance 8. Phase rule 12. Bulk composition vs phase composition 5. two-phase field 7. binary compound 4. Proportions (amounts) of phases vs compositions of phases 6. 5 Fayalite tob ali te p.f.Pelton. 18 atit He m 1 773 16 1 67 3 Wustite p.f 0.4 0. 98(9).8 0.f 0. .Phase Relations in FeO-Fe2O3-SiO2 0.6 187 3 e Spinel (Fe3O4) 172 3 0.p.2 Fe2O 325 Ref:E. Jak.6 Tr i d 2 Liquids 0 . 847-854 . 1 0.Hayes. 2 Cr is ym ite Liquidus Isotherms 0.4 Fe3 O4 mass fraction 1 92 3 2 3 Spinel p.7 0.5 0. 2 Fe2 SiO4 0. P.3 0.8 0.4 0 .7 0. Int.5 0. 9 FeO 14 73 0 .p . 0.6 0.9 SiO2 p ..8 0.f. of Materials Research (2007).1 Fe me t al 1523 1573 23 0.p. A. J.7 0. Decterov S.D.p . ¿Como construir los diagramas de fases? Experimentos o Simulacion (basado en datos experimentales) . IV. Fast quenching to produce a well quenched glassy slag. II. Analysis of matte.TAL APPROACH TO PHASE EQUILIBRIUM DETERMINATION I. Small samples suspended on a substrate III. Control of PO2 and PSO2 and T. glassy slag and crystals by EPMA . erimental equipment Working thermocouple Alumina sheath covers EPMA quantitative composition analysis Pt wire (sample holder) Gas outlet Heating elements High Vacum Specimen Quenching and sample preparation Controller Thermocouple Hot zone Electron and X-ray detectors Incident Electrons Sample Secondary Electrons Auger Electrons Back Scattered Electrons Continuum X-ray Alumina tube Fluorescent X-ray Gas Inlet Removable end Watch glass & O-ring seal Characteristic X-Ray 1mm Quantitative composition of the 1mm probe . PO2 of 10-8 atm 1200 0C. SiO2 -The phase compositions are measured with EPMA with accuracy within 1 wt % or better for Fe.1 for Cu.Methodology -The compositions of the phases (glass and solids) are then measured using a JEOL JXA 8200L (trademark of Japan Electron Optics Ltd. Si and Ca and within 0.. Cu saturation CaO FeO . Tokyo) electron probe X-ray microanalyzer (EPMA) with Wavelength Dispersive Detectors (WDD). ¿Como construir los diagramas de fases? simulación . Ranges of stability for a system using the Gibbs Free Energy of phases at equilibrium . SiO2 2 .SiO2 𝑞FeO.Parameters of equations of Gibbs energy for the system FeO-Fe2O3-SiO2 and results of simulation 𝑜 𝑜 𝐺𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 = 𝑛FeO 𝐺FeO + 𝑛SiO2 𝐺SiO − T∆𝑆 𝑐𝑜𝑛𝑓𝑖𝑔 + 2 𝑛FeO. BASED 33 .THERMODYNAMIC MODELLING FactSage Computer Package -----------------------------------GIBBS FREE ENERGY MINIMISATION SOFTWARE + THERMODYNAMIC DATABASES + INPUT/OUTPUT WINDOWS . …) / /METAL ALLOYS / /SOLIDS / /AQUEOUS SOLUTIONS/ 34 . S.. SO3.Over 5000 stoichiometric compounds FactSage THERMODYNAMIC DATABASES .Advanced solution models .Evaluated complex solutions ----------------------------------------------Multi-component Multi-phase Equilibria /GAS / /SLAG (molten oxides) / / MOLTEN SALTS (Cl. Al2O3 – CaO – FeO – Fe2O3 -MgO -Na2O -K2O 35 .Al2O3 .SiO2 SiO2 .THERMODYNAMIC MODELLING: FactSage Thermodynamic Databases developed by PYROSEARCH in collaboration with CRCT: PbO – ZnO– CaO – FeO – Fe2O3 . TEMPERATURE .THERMODYNAMIC MODELLING INPUT: OPERATIONAL PARAMETERS .ATMOSPHERE (PO2) FactSage OUTPUT: .AMOUNTS AND COMPOSITIONS HOMOGENEOUS AND HETEROGENEOUSS LAG VISCOSITY MODELS 36 OF ALL PHASES .COMPOSITION . Algunos diagramas utilizados en la pirometalurgia del cobre . 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 38 .4wt% SiO2:0.Phase diagram of FeO-FeS-SiO2 ¿Porque se presenta la separación de fases? matte FeO:27.8wt% FeS:17.4wt% FeS:72.3wt% Basic Principle of Matte-Slag separation In the ternary FeS-FeO-SiO2 system.16wt% Slag FeO:54.9wt% SiO2:27. Binary system Cu2S-FeS 1400 Temperature 0C 1200 Matte 1000 800 600 400 200 wt% FeS 39 . Binary system Cu-Cu2S 40 . Formal definition Particular states of simple systems that. time independent.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. Callen. N2. and the mole numbers N1. are characterized completely by the internal energy U. They are called equilibrium states. by definition.…Nr of the chemical components. Such simple systems states are. all –encompassing problem of thermodynamics is the determination of the equilibrium state that eventually results after the removal of internal constrains in a closed. The single. Operationally. thermodynamics and an introduction to thermostatistics). macroscopically. a system is in an equilibrium state if its properties are consistently described by thermodynamic theory. . composed system (Herbert B. . and (often) mechanically separable of other phases. • Chemical species: atoms. In such a mixture. • 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. molecules. physically distinct. molecular fragments. subjected to achemical process or to a measurement. known as a solvent • Crystallisation path: Sequence of appearance of phases during cooling. ions. a solute is a substance dissolved in another substance. -Single phase field: Only one phase -Two phase field: Two phases coexist -Three phases: ….DEFINICIONES • Phase field: region of material in the phase diagram that is chemically uniform. etc.. 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.DEFINICIONES Liquidus: temperature (a curve on a phase diagram) above which a material is completely liquid. 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. 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 1 A liquid and solid phase of fixed proportions react at a fixed temperature to yield solid phase. . Incongruent melting: occurs when a substance does not melt uniformly and decomposes into another substance. . “Phase Diagrams for Ceramists.Levin.204 Ternary systems: pp..231 D.156 Binary systems:pp.204. West “Ternary Equilibrium Diagrams”. Vol.Lee “Chemical Termodynamics for Metals and Materials” Phase Equilibria and Free energies pp. R. 1981 Osborne and Muan.144. “Phase equilibria among oxides in steel making” 1965 E. Vancouver.G. 1964 Akira Yazawa: “Thermodynamic considerations of copper smelting”.References: H. F.. 166. August 1981 . 28th Congress of IUPAC. Canadian Metallurgical Quarterly. Number 3 (1974) Akira Yazawa: “Extractive Metallurgical Chemistry with Special Reference to44 Copper Smelting”. 13.. FIN PRIMERA SESIÓN . ¿Que información requerimos para describir el proceso? ¿ Que reacciones ocurren durante el proceso? ¿ Como representar esta información en forma matemática? ¿ Como representar la información en forma grafica? ¿ Como obtener la información necesaria para determinar los parámetros de la formulación matemática? ¿ Cual es la confiabilidad y que tan precisa es la información? ¿ Cuales son los rangos de temperatura y composición donde las fases se encuentran en estado solido. liquido o gaseoso?. ¿ Porque se presenta la separación de fases? ¿ Como sistematizar la información relacionada a las reacciones quimicas? ¿ Cuales son los mecanismos en la cinética de las reaccione? . g.e. Smelting Flash Furnace – complex reactor with many zones Gas/liquid & gas/solid reaction mechanisms in reaction shaft Dust carry-over O2 + N2 SiO2 Fe3O4 Cu2S FeS2 SiO2 CuFeS2 FeS Reaction Shaft Uptake Shaft Fe3O4 Cu2S Cu2SO4 Cu2S FeS Fe3O4 SO2 SiO2 CuFeS2 Cu2SO4 FeAsS Cu2SO4 SiO2 SO2 + N2 Settler Slag “Cu2O”+“FeO”+SiO2 Slag Matte or liquid Cu metal FeS Matte Fe3O4 Liquid/liquid and liquid/solid reaction mechanisms in settler Slag Matte 14/03/2015 M Matte Decantation and liquid/liquid 47 reactions . Arsenic Sulphuric acid Weight % 27% Anode 21% Slag SCF 49% Gas emisión 3% (12 tons.As/year) 100% (400 ton.02-0.As/year) Total Copper ore (0.05 wt% As) Selective flotation. smelting and anodes production Tailings of flotation Final Gas Emissions of As As in Dust Final Slag Water contamination with As Electrolyte copper and sub-products Leaching? or Smelting? As disposal As in Sulphuric acid . leaching or roasting As disposal Copper mineral processing. C-Volatilizacion selective de arsenico Tostacion: Volatilizacion del arsenico. oxidacion y captura como polvos de oxidos de arsenico Fe-S-O-(As-Cu-Co-…) El efecto del arsenic en el Sistema Lineas de liquidus y fases primarias .