Ferrous Processing

2011 Montreal Montreal

2012

Montreal

2012

Processing – Ferrous Metallurgy

Ferrous Processing 1

The Use of FactSage

in

Steelmaking Processes

In-Ho Jung

Dept. of Mining and Materials Eng., McGill Univ.

[email protected] Tel: 1-514-398-2608

mailto:[email protected]




2012

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Contents


• Databases in FactSage for steelmaking applications

• Most common phase diagrams for steelmaking applications

• Simple examples of Equilib for various functions of FactSage:

Trget/Transition, Stream, Heat balance, Open, Fixing partial pressure,

Fe saturation, etc.

• Simple examples of Phase diagram for various functions of FactSage:

Binary diagram, Ternary and multi-component - Isothermal, isopleth diagram.

• Application: Activity calculations in binary, ternary and multi-component systems

Slag and FeLq

• Application: Addition of new component (user defined) to Slag: V2O3 oxide in slag

Henrian activity coefficient

• Application: Addition of new compound and solution (user defined) in calculations:

MnCr2O4-MnAl2O4 ideal solid solution

• Application: Phase diagram calculations (advanced)

Phase diagram calculations with Fe oxide and Fe saturation:

Multi-component phase diagrams, slag – refractories or inclusions

• Application: Non-metallic Inclusions (inclusion formation, stability diagram)

• Application: Solidification (Scheil cooling) of slag and steel

• Application: Refractory design (thermodynamic stability)

• Macro processing: Process simulations (simple/advanced examples, Rotary Kiln, etc)

• Viscosity module: Slag and Glass viscosity calculations

• FactOptimal module: Process condition optimization / new alloy development


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2012 Ferrous Processing 3

Databases in FactSage for steelmaking

applications

Brief History of Database Development

Details of Oxide Solution Database for Steelmaking Applications


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Database in FactSage

Brief History of FACTSAGE Database Development

1976~2001: F*A*C*T 2001~present: FactSage (a fusion of F*A*C*T + ChemSage)

< 1998 : FACT database (before 1998)

1999~2003 : FACT53 database

2000~2004 : FACT Consortium project (2000~2004): 16 companies

pyrometallurgy (ferrous, non-ferrous), hydrometallurgy-corrosion, glassmaking

- FACT53 database FToxid, FTmisc, FThall, FTsalt, FThelg,..

- New alloy databases: FSStel, FSlite, FScopp, SGTE, ….

2004~2010 : Mini-consortiums

- Al consortium (Alcoa, Alcan, and Norsk-Hydro)

- Glass consortium (Corning, Schott, and Saint-Gobain)

- Light alloy (Al, Mg) consortium (Al consor., GM and MagNET): FTlite

- Steelmaking consortium (Posco, RIST, and Tata Steel Europe)

2011~2014 : Mini-consortiums

- Al consortium (3 companies), Glass consortium (3 companies)

- Steelmaking consortium: 11 companies Consortium database (‘CON1’)



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Database in FactSage for Steelmaking Applications

FACTPS: All gaseous species, stoichiometric solid and liquid species

(organic, inorganic)

Similar to thermodynamic table like JANAF, Barin-Kubaschewski

FToxid: Most updated Oxide database with

- many solution phases (slag, spinel, monoxide, olivine, etc.)

- pure solid and liquid oxides, No gas phase

FTmisc: FeLq solution

- most reliable liquid steel database for steelmaking calculations

(slags/refractories/gases/molten iron)

FSStel: solid and liquid steel phases

(also includes small number of gases, oxides, sulfides, nitrides, etc.)

- for steel solidifications and alloy design.

- liquid steel: reasonable calculations for steelmaking applications

For steelmaking calculations:

priority: FToxid > FeLq > FACTPS



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FToxid database

Main solution phases when T > 1550oC (steelmaking)

Slag (I option): CaO-MgO-Al2O3-SiO2-FeO-Fe2O3-MnO-Mn2O3-Ti2O3-TiO2…

+ Gas solubility such as S (SO2), P, H (OH), N, C, F, …

Spinel (I option) (SPIN): (Mg,Fe,Mn,Co,Ni,Zn)(Al,Fe,Cr,Co,Mn,Va)2O4, extensive solid solution

containing MgAl2O4, MgCr2O4, MgFe2O4, FeCr2O4, Fe3O4, FeAl2O4, Cr3O4, MnAl2O4,

MnCr2O4, MnFe2O4, etc.

(AlSp): (Fe,Mg,Mn)Al2O4-Al2O3 solution

a-, a’-Ca2SiO4 (aC2S, bC2S): Ca2SiO4 (C2S) rich solution with limited solubility of Mg2SiO4,

Fe2SiO4, Mn2SiO4,etc.

Olivine (Oliv): Mg2SiO4, Fe2SiO4, etc. (Mg,Fe,Ca,Mn,Ni,Zn,Co,Cr,etc.)2SiO4, covering

forsterite (Mg2SiO4), fayalite (Fe2SiO4), -Ca2SiO4, monticellite CaMgSiO4, tephroite Mn2SiO4.

I option specially when Ca2SiO4 exists.

Corundum (CORU): (Al,Cr,Fe,Mn)2O3 solution, the solution of Al2O3, Cr2O3 and Fe2O3. Solid

miscibility gaps exist between the constituents. I option required.

Monoxide (halite) (MeO_): of CaO-MgO-FeO-MnO-NiO-Fe2O3-Al2O3-Cr2O3 etc. well-known

lime (CaO), periclase (MgO) and wustite (FeO). I option especially when CaO and MgO exist

together.



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Mn/Ti oxides:

i) ilmenite (ILME): (FeTiO3(ilmenite)–Ti2O3–MgTiO3–MnTiO3 + Al2O3),

ii) pseudo-brookite (PSEU): (Ti3O5–FeTi2O5-MgTi2O5–MnTi2O5 ),

iii) Ti-spinel (TiSp): (Mg,Fe,Mn)[Mg,Fe,Mn,Ti,Al]2O4

iv) Rutile (TiO2):TiO2 + Ti2O3-ZrO2 solid solution

Mullite (Mull): non-stoichiometric Al6Si2O13 with possible solubility of B.

(MulF): stoichiometric Al6Si2O13 with dilute Fe6Si2O13.

Melilite (Mel_): Ca2[Mg,Fe2+,Fe3+,Al](Fe3+,Al,Si)2O7. Akermanite Ca2MgSi2O7 and gehlenite

Ca2Al2SiO7 form the melilite solid solution stable below 1590 °C.

Main solution phases when T < 1550oC (solidification of slag)

Wollastonite (Woll): (Ca,Mg,Mn)SiO3, which is a CaSiO3 rich phase stable below 1300 °C.

Pseudo-wollastonite is stoichiometric CaSiO3 stable below 1550 °C.

pyroxene (pPyr, oPyr, cPyr): (Mg,Ca,Fe)[Mg,Fe]Si2O6, which is a MgSiO3-rich phase stable

below 1560 °C. proto-, ortho-, low-clino-pyroxene exist. Clino-pyroxene is a CaMg2SiO6-rich

phase, which is stable below 1390 °C.

Rhodonite (Rhod): (Mn,Ca)SiO3, a MnSiO3-rich solid stable below 1300 °C.

FToxid database



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Main solution phases in CaO-Al2O3-SiO2-FetO system when high PO2 (air)

CAFS Ca2(Al,Fe)8SiO16, CAF6 Ca(Al, Fe)12O19, CAF3 Ca(Al,Fe)6O10, CAF2 Ca(Al,Fe)4O7

CAF1 Ca(Al,Fe)2O4, C2AF Ca2(Al,Fe)2O5, C3AF Ca3(Al,Fe)2O6

Main solution phases when T < 1550oC (mould flux, Na2O containing system)

Nepheline (Neph): NaAlSiO4 with excess SiO2.

Carnegeite (Carn): NaAlSiO4 with excess SiO2.

NaAlO2 (NASl): low temperature - NaAlO2 with excess NaAlSiO4

NaAlO2 (NASh): high temperature - NaAlO2 with excess NaAlSiO4

Combeite (NCSO): Na4CaSi3O9 (bombeite) – Na2Ca2Si3O9 solid solution

Feldspar (Feld): complete solution between Anorthite(CaAl2Si2O8)-Albite(NaAlSi3O8)

NCA2: (Na2,Ca)O·Na2O·2Al2O3 solid solution

C3A1: Ca3Al2O6 dissolving Na2O, (Ca,Na2)1Ca8Al6O18 solution

Most updated version of Na2O containing system in available in “CON1” database

FToxid database



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FTmisc (FeLq) and FSStel

FeLq Liquid Fe containing Ag,Al,B,Ba,C,Ca,Ce,Co,Cr,Cu,H,Hf,La,Mg,Mn,Mo,N,Nb,Nd,Ni,O,P,Pb,Pd,S,Si,

Sn,Ta,Th,Ti,U,V,W,Zr. This phase is better suited for calculations involving iron and steelmaking

processes (optimized for iron-rich solutions only).

Based on the Unified Interaction Parameter Formalism (advanced than Classical Wagner’s

Interaction parameter formalism) with associate model for deoxidation. Many interaction

parameters between metallic elements are taken from JSPS (Japanese compilation)

FSStel database FCC/BCC: Fe / Carbide / Nitride are all treated as FCC phases

Fe with N and C : use J option (3-miscibility gaps).

Fe with N or C : use I option (2-miscibility gaps).

Also recommend to use I option for BCC phase For example, see Fe-Ti-Nb-C-N example.

Liquid: O and S are treated as associate model

FCC ordered phase (FCC_L12), BCC ordered phase (BCC_B2) normally slow down the

calculations significantly. If you are not really interested in order/disorder transitions, do not to select

these phases.

Carbon: when C content is lower than ~ 1%, Fe3C (metastable) phase is normally formed instead

of C (stable). So, in the selection of solid phases, “unselect” C solid phases.



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Most common phase diagrams for

Steelmaking Applications

CaO-MgO-SiO2-Al2O3-FetO-MnO

Na2O-CaO-Al2O3-SiO2

MnO-TiO2


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Phase vs. Phase diagram

Fe(liquid)+MW+Slag

Schenck and Pfaff[54]

Gokcen[69]

Fischer and Ende[72]

Taylor and Chipman[70]

Shim and Ban-Ya[74]

Fe(liquid)+MW

Fe(bcc) + MW

Fe(fcc) + MW

Fe(liquid)+Slag

Scheel et al.[73]

Fetters and Chipman[71]

molar ratio FeO/(MgO+FeO)

Tem

per

atu

re,

oC

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

Slag

Lime

Wustite

Ca2Fe2O5 + WustiteLime + Ca2Fe2O5

Lime+Wustite

Lime + Slag

Zhao et al.[45]

Abbatista[20]

Allen and Snow[17]

Larson[21]

Takeda[22]

Timucin[23]

Ca

2F

e2O

5

1059oC

1125oC

1371oC

0.760.16

0.13

0.67

0.72

mass FeO/(CaO+FeO)

Tem

peratu

re, oC

0 0.2 0.4 0.6 0.8 1

800

1000

1200

1400

1600

1800

Monoxide; halite solution (MeO_)



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MnO

Liquid

2 Liquids

SiO2(Crist)

SiO2(Trid)

MnSiO3Mn2SiO4

1842oC

1328oC

1251oC

1347oC

1293oC

1465oC

1702oC

0.59 0.992

0.490.43

0.29

mole fraction MnO

Tem

pera

ture

(oC

)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1200

1300

1400

1500

1600

1700

1800

1900

Olivine: M2SiO4

MgSiO3-rich: pyroxene

MnSiO3-rich: rhodonite



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Liquid

Mullite(Al6Si2O13)

Al2O3

SiO2(Trid)

SiO2(Crist)

1890oC 1890

oC

1465oC

1596oC 0.96

0.334

2054oC

1723oC

mole fraction SiO2

Tem

pera

ture

(oC

)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2504oC

1769oC

1527oC 0.77

0.55

1842oC

MnO

Mn

Al 2

O4

Al2O3

Jacob[16]

Olsen & Heynert[17]

mole fraction MnO

Tem

pera

ture

(oC

)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

Al 2

O3

Spinel

Alper et al[22]

Viechnicki et al[23]

Saalfeld and Jagodzinski[32]

Viertel and Seifert[30]

Mori[24]

Stubican and Roy[25]

Henriksen and Kingery[27]

Whitney and Stubican[28]

Rankin and Merwin[21]

2122

(1994, 0.79)

2054

2825

0.07

Frenkel et al[26]

Roy et al[31]

Shirasuka and Yamaguchi[29]

Lejus[33]

(1985, 0.36)

(2008, 0.92)

Liquid

Mo

no

xid

e 0.90

MgO mole fraction Al2O3

Tem

pera

ture,

oC

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

Slag

MW+Slag

SpinelMW

Slag

Spinel

Spinel + Fe2O3

MW + Spinel

MW + Slag

Roberts and Merwin[66]: phase boundaries

Willshee and White[65]: invariant points

Slag+Solid

Woodhouse and White[39]: monoxide boundary

MW+Spinel

MW

1711

Schurmann and Kolm[68]: Slag

Phillips et al.[67]

molar ratio Fe2O3/(MgO+Fe2O3)

Tem

per

atu

re,

oC

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000Spinel: A2+(B3+)2O4

Mullite



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AOlivine

Fe(liq)

Fe(s)

Fe(s2)

ASlag-liq + AOlivine

Fe(s)

ASlag-liq

Mg2SiO4 - Fe2SiO4 - Fe

Fe/(Mg2SiO

4+Fe

2SiO

4) (mol/mol) = 0.001

Fe2SiO4/(Mg2SiO4+Fe2SiO4) (mol/mol)

T(C

)

0 0.2 0.4 0.6 0.8 1

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

Fe saturation



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1422

2374

1542

1349

1985

1333

1309

1597

15221344

1362

1714

1754

16902008

1778

1758

1708

1833CaO

MgO

Al2O3(2572) (2054)

(2825)

Mole fraction

2600

2400

2200

2000

1800

1600

2100

1900

1700

15001400

MgO

Spinel

CaO

Al2O3

CaAl12O19Ca3Al2O6

CaAl2O4

(1604)

CaAl4O7

(1765)

Ca3MgAl4O8

CaMg2Al16O27

Ca2Mg2Al28O46

1766

2122

MgO Al2O3

SiO2SiO2SiO2SiO2SiO2SiO2SiO2SiO2SiO2SiO2SiO2SiO2SiO2

1435

1465

1454

1575

weight percent

1381

1445

1361

1371

1558

1548

16451863

Tw

o-L

iquid

s

SiO2(Crist)

SiO2(Trid)

Cordierite

Sapphirine

2000

1900

1800

2600

2400

2200

2000

1700

1600

1500

1400

2000

1600

1500

MgOSpinel

Al2O3

Mullite

Mg2SiO4

MgSiO3

20081985

(Mg2Al4Si5O18)

(Mg4Al10Si2O23)

(1723)

(2825) (2054)

12391328

1769

Corundum

Galaxite

Mullite

Mn2SiO4

MnSiO3

MnO

SiO2

1293

Al6Si2O13

(1890)(1347)

MnAl2O4

(2054)(1842)

(1723)

1595

1702

1890

1465

Mn2Al4Si5O18

(Mn-Cordierite)

2000

1900

1800

1700

1600

(1180)

MnO

Al2O3

1135

1119

1156

1800

1700

1600

Mn3Al2Si3O12

(Spessartite)(1200)

2 L

iquid

sCristobalite

Tridymite

1500

1400

1300

1200

1527

1251

1249

1144

1180

1157

1138

1143

1166

1194

weight percent

Tephroite

Rhodonite

1200



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[41] Osborn and Schairer

Liquid

Liquid + Mel

Mel

[22] Buddington : rxn time not enough

Liquid

Liquid + rare mel

mel + rare L

Geh-Aker (melilite solution)

Liquid

(75, 1390oC)

L+Merw

System Ca2Al2SiO7 - Ca2MgSi2O7

wt% Ca2MgSi2O7/(Ca2Al2SiO7+Ca2MgSi2O7)

T(o

C)

0 10 20 30 40 50 60 70 80 90 100

1200

1300

1400

1500

1600

1700

Melilite solid solution

Spinel solution

‘Coru’ solution



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ilmenite Ti-spinel

Pseudo-brookite




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CaO

SiO2

Al2O3

Na2O

C2AS CA

CAS2

C2S

CS

NAS2 NAS6

C: CaO

A: Al2O3

N: Na2O

S: SiO2

NA

NA6

NS

Na2O containing system: Na2O-SiO2-CaO-Al2O3

Weill et al. (1980), compliation

Feldspar

Slag

CaAl2Si2O8 - NaAlSi3O8

mole NaAlSi3O8/(CaAl2Si2O8+NaAlSi3O8)

T(C

)

0 0.2 0.4 0.6 0.8 1

1000

1400

1800

* Most updated version: ‘CON1’ database



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ASlag-liq

ASlag-liq + NaAlO2(s2)

NaAlO2(s2) + Na2Al12O19(s)

Na2O(s) + NaAlO2(s2)

Na2O(s2) + NaAlO2(s2)

Na2O(s3) + NaAlO2(s2)

NaAlO2(s2) + NaAl9O14(s)

ASlag-liq + NaAl9O14(s)

NaA

l 9O

14(s

) +

Al 2O

3(s

4)

Na2O - Al2O3

Al2O3/(Na2O+Al2O3) (mol/mol)

T(C

)

0 .2 .4 .6 .8 1

500

700

900

1100

1300

1500

1700

1900

2100

2300

2500


Rys (2008): DTA-TG, heating

Rys (2008): DTA-TG, cooling

Na

10S

iO7

Na

4S

iO4

Na

2S

iO3

Na

6S

i 2O

7

Na

2S

i 2O

5

Na

6S

i 8O

19

Na2O mole fraction SiO2

Tem

pera

ture (

K)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

700

900

1100

1300

1500

1700

1900

2100

Phase vs. Phase diagram: Na2O-Al2O3-SiO2 system


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Phase vs. Phase diagram: Na2O-Al2O3-SiO2 system

NASh

Carg

Neph

NASl



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Moir and Glasser (1974)(1:2:3)

(1:2:3) + (2:1:3)

(1:2:3) + bCS

L + (1:2:3)

(2:1:3)

L + (2:1:3)

(2:1:3) + NS

aCS

aCS + (1:2:3)

aCS + bCS + (1:2:3)

L + aCS

bCS + (1:2:3)

aCS + bCS

L

L + NS

(1:2:3)' - maybe (1:1:2)

(1:2:3)' + NS

(1:2:3) + (2:1:3) + NS

Slag

1:2:3

1:2:3 + Na2SiO3(s)

Na2SiO3(s) + Na4CaSi3O9(s)

1:2:3 + CaSiO3(s)

1:2:3 + CaSiO3(s2)

Slag + CaSiO3(s2)

CaSiO3 - Na2SiO3

mole CaSiO3/(CaSiO3+Na2SiO3)

T(C

)

0 0.2 0.4 0.6 0.8 1

0

300

600

900

1200

1500

1800

0.2

0.4

0.6

0.8

0.20.40.60.8

0.2

0.4

0.6

0.8

SiO2

Na2O CaOWeight %

(a:b:c) = aNa2O.bCaO.cSiO2

(2:0:1)

(3:0:2)

(1:0:1)

(1:0:2)

(0:1:1)

(0:2:1)

(0:3:2)

(0:4:1)

(5:0:1)

(1:1:5)

(1:3:6)

(2:1:3) (1:2:3)

(2:1:3)

(1:0:1)

(0:1:1)

(0:0:1) - Tr.

(0:0:1) - Cr.

(0:3:2)

Morey and Bowen (1925)

(1:2:3)

(1:3:6)

(1:0:2)

(0:0:1) - Qz.

(4:3:5)

(1:1:1)

(1:2:2)

Segnit (1953)

(1:1:1)

(2:1:3)

(1:2:3)

(1:2:2)

(4:3:5)

(1:0:1)

(0:2:1)

(0:1:1)

(3:0:8)

Shahid and Glasser (1971)

(1:1:5)

(1:0:2)

(1:2:3)

(1:3:6)

(3:0:8)

(0:0:1) - Qz.

(0:0:1) - Tr.

1200 o C11

00

o C

1000

o C 1300

oC 1400

oC 1500

oC

1100

o C

SiO2 - CaO - Na2O

Phase vs. Phase diagram: Na2O-CaO-SiO2 system

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

Na2O CaOmole fraction

(a:b:c) = aNa2O.bCaO.cSiO2

(2:0:1)

(3:0:2)

(1:0:1)

(1:0:2)

(0:1:1)

(0:2:1)

(0:3:2)

(0:4:1)

(5:0:1)

(1:1:5)

(1:3:6)

(2:1:3) (1:2:3)

(1:2:2)

(1:1:1)

(4:3:5)

(3:0:8)

CaO-Na2O-SiO2

FactSage

?

NCSO: 1:2:3 solid solution



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0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.90.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Na2O

CaO Al2O3mole fraction

(a:b:c) = aNa2O.bCaO.cAl2O3

(0:1:1) (0:1:2) (0:1:6)

(1:8:3) (1:0:9)

(1:0:6)

(0:3:1)

(1:0:1)

CaO(s)

NaAlO2(s2)

1:1:2 NaAl9O14(s)

Al2O3(s4)CaAl2O4(s)CaAl4O7(s)

Na2O - Al2O3 - CaO

Projection (Slag)

FactSage

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

mole fraction

Slag

Na2O

CaO Al2O3mole fraction

N(a)C(b)A(c) = aNa2O.bCaO.cAl2O3

CA CA2 CA6

NC8A3 NA9NA6

C3A

NCA2s.s

NC3A8

NA

Verweij and Saris (1986), maximum solubility

Na2O - Al2O3 - CaO

1200oC

FactSage

Phase vs. Phase diagram: Na2O-Al2O3-CaO System

NCA2: (Na2,Ca)O·Na2O·2Al2O3 solid solution



2012

Montreal

2012

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

MELCgNe

PW

Juan (1950)Ca2Al2SiO7

CaSiO3 NaAlSiO4mass fraction

Ca2Al2SiO7


T(min) = 1162.95 oC, T(max) = 1594.98

oC

Melilite

CaSiO3(s2)

Ca3Si2O7(s)

Nepheline

Carnegieite

10/25/2008

D:\Work\CRCT\2007_MoldFlux_POSCO\Na2O-CaO-SiO2-Al2O3\quaternary_parameter\PD_CaSiO3-Ca2Al2SiO7-NaAlSiO4.emfCaO

SiO2

Al2O3

Na2O

Phase vs. Phase diagram: Na2O-Al2O3-SiO2-CaO System



2012

Montreal

2012

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0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

CA2S2CgNeC3APWC2AS2b-A

Gummer (1943)CaAl2Si2O8


CaAl2Si2O8


T(min) = 1163.86 oC, T(max) = 1555

oC

Feldspar

CaSiO3(s2)

Melilite

Carnegieite

10/25/2008

D:\Work\CRCT\2007_MoldFlux_POSCO\Na2O-CaO-SiO2-Al2O3\quaternary_parameter\PD_CaSiO3-CaAl2Si2O8-NaAlSiO4.emfCaO

Al2O3

Na2O

SiO2

15

00




2012

Montreal

2012

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1:2:32:1:3CgNePWNSW

Spivak (#1342)NaAlSiO4

CaSiO3 Na2SiO3mass fraction

NaAlSiO4


NaAlSiO4


NaAlSiO4


T(min) = 919.18 oC, T(max) = 1540.17

oC

Carnegieite

Nepheline

1:2:3

CaSiO3(s2)

2:1:3

Na2SiO3(s)

10/25/2008

D:\Work\CRCT\2007_MoldFlux_POSCO\Na2O-CaO-SiO2-Al2O3\quaternary_parameter\PD_NaAlSiO4-CaSiO3-Na2SiO3.emf

CaO

Al2O3

Na2O

SiO2




2012

Montreal

2012

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0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

Na2O CaOmass fractions /(SiO2+CaO+Na2O)

T(min) = 812.79 oC, T(max) = 2394.5

oC

CaO(s)

1:1:2 Ca2SiO4(s3)

Ca2SiO4(s2)Melilite

Ca3Si2O7(s)

1:2:3CaSiO3(s2)

Nepheline

Feldspar

Al6Si2O13(s)

Na2Ca3Si6O16(s)

Feldspar

NaAlO2-NaAlSiO41

NaAlO2-NaAlSiO4

NaAlO2-NaAlSiO41

SiO2 - CaO - Na2O - Al2O3

15wt% Al2O

3 section

SiO2

CaO

Al2O3

Na2O

1400

1300

1200

1100




2012

Montreal


Simple examples of Equilib

Target/Transition, Stream, Heat balance, Open,

Fixing partial pressure, Fe saturation, etc.


2012

Fe-LIQUID

Si(s) + FeSi2(s)

Si(s) + Fe3Si7(s)

Fe-LIQUID + Si(s)Fe-LIQUID + FeSi(s)

BCC_A2

FCC(c,n)

BCC_B2

FeSi(s) + Fe5Si3(s)

FeSi(s) + Fe2Si(s)

Fe - Si

mass 100Si/(Fe+Si)

T(C

)

0 20 40 60 80 100

200

400

600

800

1000

1200

1400

1600

1800

1030°C

5wt%Si

Fe-Si binary phase diagram - Fe-5wt.% Si at 1030 oC



2012

Reactants Window - Fe-Si at Fe-5wt.% Si

Reactants Window

Data Search



2012

Selection of solid phases

Pure solids

Menu Window - Fe-5wt.% Si at 1030 oC



2012

Montreal

2012

Results Window - Fe-5wt.% Si at 1030 oC



2012

Menu

Fe-5wt.% Si from 200 oC

to 1800 oC every 200 oC

Fe-5wt.% Si transition calculations



2012

Fe-5wt.% Si formation target for liquid phase

F – formation target phase



2012

Fe-5wt.% Si precipitate target for liquid phase

P – precipitate target phase



2012

Montreal

2012

Creating new stream : Fe-0.1C-1Mn-1Si at 1600oC



2012

Montreal

2012

Save the liquid FeLQ

phase as a stream

Creating new stream : Fe-0.1C-1Mn-1Si at 1600oC



2012

Montreal

2012

Import stream : Fe-0.1C-1Mn-1Si at 1600oC



2012

Montreal

2012

Heat balance: Fe-0.1C-1Mn-1Si(1600oC) + Al (25oC)

Adiabatic calculation :

Delta(H) = 0

Calculated adiabatic

temperature = 1605.5 oC



2012

Montreal

2012

RH – Vacuum degassing process

Open Calculation - off-gas removal

Stream Fe-0.1C-1Mn-1Si + O2

at 1600oC and 0.01 atm



2012

Montreal

2012

Carbon content decreases due

to the reactions:

C + O2 = CO2

C + 0.5O2 = CO

New slag formed due to Si and

Mn oxidation:

Mn + 0.5O2 = MnO

Si + O2 = SiO2

Open Calculation - results



2012

Montreal

2012

1

2

3

Open Calculation - plot of log(wt% liquid steel)



2012

Montreal

2012

Fe_FeLQ Fe_FeLQ Fe_FeLQ Fe_FeLQ

Mn_FeLQ Mn_FeLQ Mn_FeLQ Mn_FeLQSi_FeLQ Si_FeLQSi_FeLQ

Si_FeLQ

O_FeLQ O_FeLQ O_FeLQ O_FeLQ

C_FeLQ C_FeLQ C_FeLQ C_FeLQ

100% [FTmisc-FeLQ_Fe-liq] + <A> O2

c:\FactSage\casestudy\Equi0.res 21May09

- page -

log

10(w

eig

ht

%)

1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00

-4.00

-3.00

-2.00

-1.00

0

1.00

2.00

Open Calculation - log(wt%) vs page



2012

Montreal

2012

Fixed pO2 in Fe-Cr-O2

2

Specify the activity of the selected

species or set a range of activities

(linear or log scale)

Fixed activity of gas and solid species

3

1



2012

Montreal

2012

Results at log(pO2) = -20

Small amount of Cr2O3

can form on top of the

Fe-20%Cr alloy

Fixed partial pressure of a gas : O2



2012

Montreal

2012


Fixed pO2 in MgO-FetO-SiO2 slag



2012

Montreal

2012



The amounts of FeO and Fe2O3 change with PO2





2012

Montreal

2012

Fixed activity of Fe: Fe saturation

Slag (CaO-MgO-SiO2) and liquid Fe equilibration at 1600oC

One way to fix Fe saturation in steelmaking

calculations is to add a small amount of Fe as

an input component



2012

Montreal

2012

Gas / Slag (CaO-MgO-FeO-SiO2) / Liquid Fe equilibration

Fixed partial pressure of a gas : Fe saturation and fixed SO2



2012

Montreal

2012

Gas (SO2, S2, O2, etc.)

Slag (CaO, MgO, FeO, …

CaS, MgS, FeS, etc.)

Fe-Lq (O, S, etc.)

Equilibration reactions include:

CaO + SO2 = CaS + 2O

SO2 = 2O + S

CaO + FeS = CaS + FeO

……

Fixed partial pressure of a gas : Fe saturation and SO2



2012

Montreal

2012

Composition Target: slag / liquid steel equilibrium

“ How to calculate optimum amount of CaSi to reduce S

in liquid steel to a targeted composition”

Composition target: target S content in liquid steel



2012

Montreal

2012

Add CaSi (<A>) to reduce [%S] in Fe-LIQUID to 0.002%.




2012

Montreal

2012


Amount of CaSi = 0.96 gram to obtain [%S] = 0.002%



2012

Fe-0.01C-0.01N-0.03Nb-0.07Ti-0.5Mn: three possible FCC phases

J option for FCC phase: Fe steel containing (Ti,Nb)(C,N) ppts



2012

FCC#1 FCC#1 FCC#1 FCC#1 FCC#1

FCC#3 FCC#3 FCC#3 FCC#3 FCC#3

99.39 Fe + 0.01 C + 0.01 N + 0.03 Nb +

T(C)

log

10(g

ram

)

0800 1000 1200 1400

-03

-01

01

03

Austenite, Ti and Nb carbo-nitrides are all FCC. In the

FSStel database, all these fcc phases are modeled as a

single FCC_A1 solution with three possible miscibility gaps.

J option for FCC phase: Fe steel containing (Ti,Nb)(C,N) ppts



2012

Montreal

2012

AlNMnS

M7C3

Cementite

Temperature, oC

ph

ase

fra

cti

on

(w

eig

ht

percen

t)

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600

0.0

0.2

0.4

0.6

0.8

1.0

FCC

BCC

Liquid

Cementite

Temperature, oC

ph

ase

fra

cti

on

(w

eig

ht

percen

t)500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600

0

10

20

30

40

50

60

70

80

90

100

Precipitation of AlN and MnS in a commercial Si-steel

Fe-0.054C-3.2Si-0.1Mn-0.028Al-0.015X-0.007S-0.0075N-0.05X-0.2X (wt%): Oriented Si-Steel

2nd recrystallization temp (pinning)



2012

Montreal

2012

Phase diagram / Phase fraction of 430 Stainless Steel

BCC

FCC

M23C

SIGMA

Liquid

Temperature, (oC)

ph

ase

dis

trib

uti

on

, w

t%

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600

0

10

20

30

40

50

60

70

80

90

100

Liquid

BCC

L+BCC

BCC+FCC

BCC + FCC + M23C6

BCC + M23C6

SIGMA + BCC + M23C6

wt% C

Tem

per

atu

re,

oC

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

Fe-16.2Cr-0.06C-0.3Si-0.4Mn-0.3Ni-0.015X(wt%): STS430



2012

Montreal


Simple examples of Phase diagram

Binary phase diagram

Ternary and multi-component systems


2012

Montreal

2012

There is a stable miscibility gap in slag; automatic selection by FactSage

Binary phase diagram: CaO-SiO2



2012

Montreal

2012

ASlag-liq

ASlag-liq + ASlag-liq#2

ASlag-liq + SiO2(s6)

SiO2(s4) + CaSiO3(s2)

Ca2SiO4(s3) + CaO(s)

Ca3SiO5(s) + CaO(s)

CaO(s) + Ca2SiO4(s2)

ASlag-liq + Ca2SiO4(s3)

ASlag-liq + CaSiO3(s2)

CaO - SiO2

mass 100SiO2/(CaO+SiO2)

T(C

)

0 20 40 60 80 100

1000

1200

1400

1600

1800

2000

There is a stable miscibility gap in slag.

Binary phase diagram: CaO-SiO2



2012

Montreal

2012

Ternary phase diagram: CaO-SiO2-Al2O3 isothermal section



2012

Montreal

2012

0.1

0.2

0.3

0.4

0.5

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0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

CaO Al2O3mass fraction

ASlag-liq


ASlag-liq + Mullite

ASlag-liq + Al2O3(s4)

ASlag-liq + CaO(s)

ASlag-liq + Ca2SiO4(s3)

CaO - SiO2 - Al2O3

1550oC

FactSage

Ternary phase diagram: CaO-SiO2-Al2O3 isothermal section



2012

Montreal

2012

SiO2

CaO Al2O3

1:1

Ternary system: section in ternary (isopleth)



2012

Montreal

2012

ASlag-liq

ASlag-liq + Al2O3(s4)

ASlag-liq + CaAl12O19(s)

ASlag-liq + Ca2Al2SiO7(s)


CaO - SiO2 - Al2O3

mass (CaO-SiO2)/(CaO+SiO

2+Al

2O

3) = 0

mass 100Al2O3/(CaO+SiO2+Al2O3)

T(C

)

0 20 40 60 80 100

1000

1160

1320

1480

1640

1800

CaO-SiO2-Al2O3 Vertical section at

(wt%CaO/wt%SiO2 ) = 1

Ternary system: section in ternary (isopleth)



2012

Montreal

2012

Oxidation diagram: Fe-Cr-O2

Combination of many databases:

FACT53: gases (if necessary)

FToxid: oxide phases

FSStel: fcc, bcc and other metallic phases



2012

Montreal

2012

Log pO2 for y-axis variable

ASpinelASlag-liq + ASpinel

Fe-LIQUIDBCC_A2

Fe-LIQUID + M2O3(corundum)

M2O3(corundum) + ASpinel

Fe-LIQUID + ASpinel

Fe - Cr - O2

1600oC

mole Cr/(Fe+Cr)

log

10(p

(O2))

(atm

)

0 0.2 0.4 0.6 0.8 1

-20

-17

-14

-11

-8

-5

Oxidation diagram: Fe-Cr-O2



2012

Montreal

2012

Predominance diagram: Fe-Mn-O2-S2

Combination of many databases:

FACT53: gases (if necessary)

FToxid: oxide phases

FSStel: fcc, bcc and other metallic phases



2012

Montreal

2012

ASlag-liq

FCC(c,n) + MnS(s)

BMonoxide + FCC(c,n)

FCC(c,n)

ASlag-liq + FCC(c,n)

ASlag-liq + Fe-LIQUID

BMonoxide

BSpinel

BMonoxide + BSpinel

MnSO4(s) + FeSO4(s)

BSpinel + MnSO4(s)

O2 - S2 - Fe - Mn

1300oC, mass Mn/(Fe+Mn) = 0.3

log10(p(S2)) (atm)

log

10(p

(O2))

(atm

)

-20 -16 -12 -8 -4 0

-20

-16

-12

-8

-4

0

Predominance diagram: Fe-Mn-O2-S2



2012

Montreal

2012

This is NOT 10% Al2O3 section !!

Quaternary diagram: iso-composition section



2012

Montreal

2012

How to calculate 10% section exactly ?

CaO+MgO+SiO2 = 1.0 (100%), Al2O3 should be 10%

CaO+MgO+SiO2 = 1.0, Al2O3 = x

x/(1+x) = 0.1 (=10%)

x = 0.11111

So, if we give Al2O3 = 0.11111 Al2O3 = 10%

2) Click here

= 10% Al2O3

This is 10% Al2O3 section !!

1) Equilib calculation mode

Quaternary diagram: iso-composition section



2012

Montreal

2012

Quaternary system: CaO-Ca2SiO4-MgAl2O4



2012

Montreal

2012

Liquid

FeS

i 2

BCC

FCC

FeS

i

Fe

3Si 7

Fe

5S

i 3

Fe

2S

i

Si

weight percent Si

Tem

pera

ture, o

C

0 10 20 30 40 50 60 70 80 90 100

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

Alloy Design: Electric steel (Si-steel)

Phase diagram of Fe-Si system



2012

Montreal

2012

BCC

BCC + Fe3C

FCC

LIQUID

FCC+BCC

Fe - C - Si

C = 25 ppm

wt% Si

Tem

per

atu

re,

oC

0 1 2 3 4 5 6

500

600

700

800

900

1000

1100

1200

1300

1400

1500


Alloy Design: Fe-Si + C



2012

Montreal

2012

BCCFCC

BCC+Cementite

0.05% C

0.03% C

0.01% C

No Carbon

weight percent Si

Tem

pera

ture, o

C

0 1 2 3 4 5 6 7 8 9 10

700

800

900

1000

1100

1200

1300

1400

1500Alloy Design: Fe-Si + C




2012

Montreal

2012

BCCFCC

0.1% Mn

Fe-Si, Fe-Si-0.03Al

weight percent Si

Tem

pera

ture, o

C

0 1 2 3 4 5

700

800

900

1000

1100

1200

1300

1400

1500

Alloy Design: Fe-Si + Al, Mn




2012

Montreal

2012

FCC + SiO2(Trid)

Mono + Fe2SiO4Spinel + Fe2SiO4

Spinel + SiO2(Trid)

SiO2(Trid) + Fe2O3

Fe2O3 + SiO2(Quar)

Mono + Slag

Spinel + Slag

BCC

BCC + SiO2(Trid)

FCC + Slag

FCC + Fe2SiO4

BCC + Fe2SiO4

BCC + SiO2(Quar)

BCC + SiO2(Trid)

Spinel + SiO2(Quar)

Temperature, oC

log

10(p

(O2))

(a

tm)

800 900 1000 1100 1200 1300

-20

-17

-14

-11

-8

-5

Mono = MgO-FeO solutions

Formation of base coating on the surface of a commercial Si steel



2012

Montreal


Application: Activity calculations

Slag: binary, ternary and multi-component systems

FeLq : oxygen and alloying elements


2012

Activity calculations – Binary system



2012

Montreal

2012

Activity calculations – Binary system

Activity of solid or liquid standard state) ?



2012

Montreal

2012

Activity calculations – Ternary system

Calculation of iso-activity line of SiO2

in the CaO-MgO-SiO2 system



2012

Montreal

2012


Save results in excel

or spread sheet form



2012

Montreal

2012


Plot the results in triangle diagram

- Prepare the triangle frame

- Plot the A,B,C coordinate numbers in triangle diagram



2012

Montreal

2012

Activity calculations – Quaternary or higher order system

Composition of Al2O3 is NOT 0.1

Impossible to calculate iso-activity line of

A with fixed B composition in quaternary

A-B-C-D system yet.



2012

Montreal

2012

Activity calculations – Quaternary or higher order system

A. Draw phase diagram of A-B-C with fixed D, and Check the iso activity point

manually of A in phase diagram mode

B. Calculate activity of A in entire A-B-C with fixed D section and manually connect

iso-activity of A.

In future, iso-activity calculation mode will be added into Phase Diagram module.



2012

Montreal

2012

Activity of oxygen (wt% standard state) in liquid steel

Log aO(wt%) = Log(aO in FeLq) - Log((EXP(-15280/T+3.5)*55.847/100/16))

where T in Kelvin

)state.stdHenrian(aM

M100)state.std%wt(a i

Fe

ii

.).(.).(

)()(

lnln

ln

SSElementpureMssHenrianM

oS.S.ElementurePM

oS.S.HenrianM

oM

aaRT

ggγRT

5.3/15280ln TγoO

Reference pure element standard state of O in FeLq : Gas (0.5 O2)

aO in FeLq

: value used in FeLq database; slightly different

depending on assessments



2012

Montreal

2012


aO in FeLq

Total dissolved Al and O

Dissolved Al, O, Al*O, Al2*O



2012

Montreal

2012

aO in FeLQ Total dissolved Al and O

Dissolved

unassociated O


Then, convert aO in FeLq to aO wt% s.s.



2012

Montreal


Application: Addition of new component in slag

V2O3 into molten slag for V distribution calculations

(Henrian Solution)


2012

Montreal

2012

New component in slag: Henrian activity coefficient

V2O3 containing slag // Liquid Fe-Al steel

All V go to liquid Fe ??

(because no V oxide in slag yet)



2012

Montreal

2012


Setting activity coefficient

of V2O3 in slag



2012

Montreal

2012




2012

Montreal

2012


V in FeLq = 0.577 wt%

V2O3 in slag = 0.134 wt%

The distribution of V between slag and metal can

be varied depending on the activity coefficient.

(evaluated from experimental data)



2012

Montreal


Application: Addition of new compound and

solution (user defined) in calculations

MnCr2O4-MnAl2O4 ideal solid solution

• New stainless steel production: high

Mn stainless steel 400 grade. High

MnO formation in AOD / VOD refining

process

• MnCr2O4-MnAl2O4 inclusion

formation in Mn and Cr containing

steels


2012

Montreal

2012

User Compound Database

(2) Select “mixer”

(1) Type the compounds

(3): add the MnO and Cr2O3 from known database

(4): select your own database (INHOBASE) and copy the result

Creating user compound database: MnCr2O4 from MnO and Cr2O3



2012

Montreal

2012


Go(cubic-MnCr2O4) = Go(MnO) + Go(Cr2O3) + Hf − TSf

Hf = -51 kJ/mol, S = 0 J/mol-K

Before Hf and Sf

after Hf and Sf



2012

Montreal

2012


Add H298, S298 and Cp, respectively

Creating user compound database:

MgCr2O4 from H298, S298 and Cp



2012

Montreal

2012

Ideal Solution between compounds

Database registeration

Priority of database



2012

Montreal

2012

Ideal Solution between compounds

MnCr2O4-MgCr2O4 ideal sol’n: (Mg,Mn)Cr2O4

Both MnCr2O4 and MgCr2O4 are selected as

ideal solution #1 with 0 activity coefficients



2012

Montreal

2012

Ideal solution between compounds

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

CaO Cr2O3mass fractions /(CaO+SiO2+Cr2O3)

Liqiud

Liquid + Ideal #1

O2 - CaO - SiO2 - Cr2O3 - MnO - MgO1700

oC, p(O

2) = 10

-11 atm, MnO/Z (g/g) = 0.1,

MgO/Z (g/g) = 0.05, Z=(CaO+SiO2+Cr

2O

3)

Ideal solution of

MgCr2O4-MnCr2O4



2012

Montreal


Application: Advanced Phase diagram

calculations

Fe oxide and Fe saturation

Multi-component phase diagrams

Slag – Refractories / Slag – Inclusions


2012

Montreal

2012

Fe oxide containing system: Fe saturation

Intentional addition of Fe to make Fe saturation



2012

Montreal

2012

Fe oxide containing system: Fe saturation

ASlag-liq + Fe(liq)

ASlag-liq + Fe(s)

ASlag-liq + Fe(s2)

AMonoxide + Fe(s2) + Fe2SiO4(s)

AMonoxide + Fe(s) + Fe2SiO4(s)

Fe(s) + FeO(s) + Fe2SiO4(s)ASpinel + Fe(s) + Fe2SiO4(s) Fe(s) + SiO2(s) + Fe2SiO4(s)

Fe(s) + SiO2(s2) + Fe2SiO4(s)

Fe(s) + SiO2(s4) + Fe2SiO4(s)

Fe(s2) + SiO2(s4) + Fe2SiO4(s)

ASlag-liq + Fe(s2) + SiO2(s4)

ASlag-liq + Fe(s) + SiO2(s4)

ASlag-liq + Fe(s) + SiO2(s6)

ASlag-liq + Fe(liq) + SiO2(s6)

ASlag-liq + ASlag-liq#2 + Fe(liq)

ASlag-liq + AMonoxide + Fe(s2)

Fe(s) + FeO(s) + Fe2SiO4(s)

FeO - SiO2 - Fe

Fe/(FeO+SiO2) (g/g) = 0.001

SiO2/(FeO+SiO2) (g/g)

T(C

)

0 0.2 0.4 0.6 0.8 1

500

700

900

1100

1300

1500

1700

1900

Monoxide = FeO. But due to slightly

different Gibbs energies of FeO stored in

two databases, FeO from FACT53

appears in the calculation. for better

calcs, remove FeO(s) from database

selection

Intentional addition of Fe

to make Fe saturation



2012

Montreal

2012

Fe oxide containing system: fixed PO2

Fixing PO2 to control the

oxidation state of Fe



2012

Montreal

2012

Fe oxide containing system: fixed PO2

Fe2O3(s) + SiO2(s2)

ASpinel + SiO2(s2)

ASpinel + SiO2(s4)

Fe2SiO4(s) + SiO2(s4)


ASlag-liq

ASlag-liq + AMonoxide

Fe(liq) + SiO2(s6)

ASlag-liq + Fe(liq)

FeO - SiO2 - O2

p(O2) = 10

-10 atm

SiO2/(FeO+SiO2) (g/g)

T(C

)

0 0.2 0.4 0.6 0.8 1

500

700

900

1100

1300

1500

1700

1900

When PO2 is fixed with selection of Fe, slag and

Fe oxides can be reduced by Oxygen to Fe at

certain temperature and composition



2012

Montreal

2012

Fe oxide containing system: fixed CO/CO2 gas

Select only CO, CO2 and O2 gas to simulate real experiment of oxide/gas equilibration.

If we select all gases, some amount of oxides can be evaporated depending on the relative amount

of gas and oxide in the calculations

Fixing PO2 by CO/CO2 gas mixture



2012

Montreal

2012


gas_ideal + ASlag-liq

gas_ideal + ASlag-liq + SiO2(s6)

gas_ideal + ASlag-liq + SiO2(s4)

gas_ideal + ASlag-liq + Fe(s2) + SiO2(s4)

gas_ideal + Fe(s2) + SiO2(s4) + Fe2SiO4(s)

gas_ideal + Fe(s) + SiO2(s2) + Fe2SiO4(s)gas_ideal + Fe(s) + Fe2SiO4(s)

gas_ideal + AMonoxide + Fe(s2) + Fe2SiO4(s)

gas_ideal + AMonoxide + Fe(s) + Fe2SiO4(s)

gas_ideal + ASlag-liq + AMonoxide + Fe(s2)

gas_ideal + ASlag-liq + Fe(s2)

gas_ideal + ASlag-liq + Fe(s)

gas_ideal + ASlag-liq + Fe(liq)gas_ideal + ASlag-liq + ASlag-liq#2

gas_ideal + Fe(s) + SiO2(s2)

FeO - SiO2 - CO - CO2

CO/(FeO+SiO2) (mol/mol) = 0.9,

CO2/(FeO+SiO

2) (mol/mol) = 0.1

SiO2/(FeO+SiO2) (mol/mol)

T(C

)

0 0.2 0.4 0.6 0.8 1

500

700

900

1100

1300

1500

1700

1900

Fixing CO/CO2 ratio



2012

Montreal

2012




2012

Montreal

2012



gas_ideal + ASpinel

gas_ideal + ASpinel + AMonoxide

gas_ideal + AMonoxide

gas_ideal + ASpinel + Fe2O3(s)

gas_ideal + ASpinel + C(s)

ASpinel + FeCO3(s) + C(s)

gas_ideal + FeCO3(s) + Fe2O3(s)

gas_ideal + ASlag-liq + ASpinel

Fe2O3 - CO - CO2

Fe2O

3/(CO+CO

2) (mol/mol) = 1

CO/(CO+CO2) (mol/mol)

T(C

)

0 0.2 0.4 0.6 0.8 1

0

200

400

600

800

1000

1200

1400

1600

1800

2000


gas_ideal + AMonoxide

gas_ideal + ASpinel + C(s)

gas_ideal + FeCO3(s) + C(s)

gas_ideal + BCC_A2 + AMonoxide

gas_ideal + FCC_A1 + AMonoxide

gas_ideal + LIQUID + ASlag-liq

gas_ideal + BCC_A2 + ASlag-liq

gas_ideal + ASpinel

gas_ideal + FeCO3(s) + Fe2O3(s)

gas_ideal + ASpinel + Fe2O3(s)

gas_ideal + ASpinel + AMonoxide

Fe2O3 - CO - CO2

Fe2O

3/(CO+CO

2) (mol/mol) = 0.1

5/3/2011

C:\Workshop\Fe2O3-CO-CO2-large-Gas.wmf

CO/(CO+CO2) (mol/mol)

T(C

)

0 0.2 0.4 0.6 0.8 1

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1mole

Fe2O3

1mole

CO-CO2 gas

<Closed system>

1mole

Fe2O3

10mole

CO-CO2 gas <Closed system>

1mole

Fe2O3

10mole CO-CO2 gas

<Open system>



2012

Montreal

2012

CaO-FetO-SiO2 system with Fe saturation



2012

Montreal

2012

CaO-FetO-SiO2 system with Fe saturation

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

CaO FeOmass fractions /(CaO+FeO+SiO2)

ASlag-liq + Fe(liq)

ASlag-liq + AMonoxide + Fe(liq)

ASlag-liq + a-Ca2SiO4 + Fe(liq)


ASlag-liq + AMonoxide + a-Ca2SiO4 + Fe(liq)

CaO - FeO - SiO2 - Fe

1650oC, Fe/(CaO+FeO+SiO

2) (g/g) = 0.001



2012

Montreal

2012

CaO-FetO-SiO2-5wt%MgO system with Fe saturation

In FactSage phase diagram module, special

attention is required for the axis setting of

quaternary or higher order system.

The first three components are Always used as

A,B,C axis with 100% (1mole) base.

Therefore, for 5% MgO section, we have to set the MgO content as 0.05263 instead of 0.05

For x MgO section: y/(1+y) = x ‘y’ = x(1-x) : ‘y’ is the value for FactSage



2012

Montreal

2012

CaO-FetO-SiO2-5wt%MgO system with Fe saturation

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

CaO FeOmass fractions /(CaO+FeO+SiO2)

ASlag-liq + Fe(liq)

ASlag-liq + AMonoxide + Fe(liq)

ASlag-liq + a-Ca2SiO4 + Fe(liq)

ASlag-liq + AMonoxide + AMonoxide#2 + Fe(liq)


CaO - FeO - SiO2 - MgO - Fe1650

oC, MgO/Z (g/g) = 0.05263, Fe/Z (g/g) = 0.001,

Z=(CaO+FeO+SiO2)

MgO saturation (MgO-FeO)

C2S saturation

BOF slag composition 5 wt% MgO section



2012

CaF

2 = 0

%

10%

Liquid (L)

L +

Ca

O

2 Liquids

20%

L +

Ca

2S

iO4

L +

Ca

3S

iO5

wt% SiO2

wt%

Al 2

O3

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

CaO-SiO2-Al2O3 + F slags for refining flux

CaO-Al2O3-SiO2 with various CaF2 content at 1650oC.

At 20% CaF2: Slag can directly equilibrated with CaO (no Ca2SiO4)

Using ‘CON1’ database

Change of Ca2SiO4 saturation

composition with CaF2 content



2012

Montreal

2012

CaO-Al2O2-SiO2 slag – MgAl2O4 refractory

50%CaO-30%SiO2-20%Al2O3 slag in mole: (CaO)0.5618(SiO2)0.3146(Al2O3)0.1236

(Equilib or Phase Diagram’s components are in molar base)

ASlag-liq

ASlag-liq + ASpinel

ASlag-liq + ASpinel + MeliliteASlag-liq + Melilite

ASlag-liq + a-Ca2SiO4


(CaO)0.5618(SiO2)0.3146(SiO2)0.1236 - MgAl2O4

MgAl2O4/((CaO)0.5618(SiO2)0.3146(SiO2)0.1236+MgAl2O4) (g/g)

T(C

)

0 0.2 0.4 0.6 0.8 1

1300

1400

1500

1600

1700

1800

Dissolution of spinel

inclusion into slag



2012

Montreal

2012

CaO-Al2O2-SiO2 slag – MgAl2O4/Al2O3 refractories

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

(CaO)0.5618(SiO2)0.3146(SiO2)0.1236

Al2O3 MgAl2O4mass fraction

ASlag-liq

ASlag-liq + ASpinel

ASlag-liq + CaMg2Al16O27(s)

ASlag-liq + Ca2Mg2Al28O46(s)

ASlag-liq + CaAl12O19(s)

ASlag-liq + ASpinel + CaMg2Al16O27(s)

(CaO)0.5618(SiO2)0.3146(SiO2)0.1236 - MgAl2O4 - Al2O3

1600oC

High Alumina (MgAl2O4-Al2O3)

Refractories dissolution into slags



2012

Montreal

2012

CaO-Al2O2-SiO2 slag – MgAl2O4/MgO refractories

ASlag-liq + a-Ca2SiO4

ASlag-liq


ASlag-liq + ASpinel

ASlag-liq + ASpinel + AMonoxide

ASlag-liq + AMonoxide + a-Ca2SiO4

(CaO)0.5618(SiO2)0.3146(SiO2)0.1236 - MgAl2O4 - MgO

1600oC

MgO/((CaO)0.5618(SiO2)0.3146(SiO2)0.1236+MgAl2O4+MgO) (g/g)

MgA

l 2O

4/(

(CaO

) 0.5

61

8(S

iO2) 0

.31

46(S

iO2) 0

.12

36+

MgA

l 2O

4+

MgO

) (g

/g)

0 0.1 0.2 0.3 0.4 0.5

0

0.1

0.2

0.3

0.4

0.5



2012

Montreal

2012

Phase diagram: Refractories design

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

(CaO)0.535(SiO2)0.25(Al2O3)0.05(MgO)0.1

MgTi2O4 MgAl2O4mass fraction

ASlag-liq + ASlag-liq#2

ASlag-liq

ASlag-liq + MgAl2O4(s)

ASlag-liq + ASlag-liq#2 + MgAl2O4(s)

ASlag-liq + ASlag-liq#2 + a-Ca2SiO4

ASlag-liq

ASlag-liq + MgAl2O4(s)

(CaO)0.535(SiO2)0.25(Al2O3)0.05(MgO)0.1 - MgAl2O4 - MgTi2O4 - Fe

1700oC, a(Fe(liq)) = 0.7943


Dissolution of MgAl2O4/MgTi2O4

refractories into slag

MgAl2O4 saturation line


2012

Montreal

2012

Dissolution of Inclusions into Molten Slags

Al

M1 M3M24M23M22M21

CP

Ca

Mg

Si

Park, Jung and Lee: ISIJ Inter. No. 11, 2006


Phase diagram between slag and inclusion to understand the

inclusion dissolution mechanism


2012

Montreal

2012


10

20

30

40

50

60

70

80

90

102030405060708090

10

20

30

40

50

60

70

80

90

(CaO)0.525(SiO2)0.475

Al2O3 MgOweight percent

M24L+MgO

L+MgAl2O4+MgO

L+MgAl2O4

MgAl2O4

M23

M22

M21

M22M21M1

M3M24M23

Fig.8

M23




2012

Montreal

2012


M22M21M1

M3M24M23

Fig.8

M3

10

20

30

40

50

60

70

80

90

102030405060708090

10

20

30

40

50

60

70

80

90

(CaO)0.58(SiO2)0.42

Al2O3 MgOweight percent

L + MgO + MgAl2O4

L + MgAl2O4

L + Ca2SiO4

L + MgO

MgAl2O4

M3




2012

Montreal


Application: Non-metallic Inclusions

Inclusion formation / composition in molten steels: Mn/Si/Ti steel

Inclusion stability diagram (phase diagram): Al/Ti steel


2012

- Evolution of non-metallic inclusions: Formation of acicular ferrite -

• Non-metallic inclusions: nucleation sites for acicular ferrite

• Acicular ferrite: enhances the strength of steel

Applications to Oxide metallurgy (Inclusion control)



2012

Evolution of Non-metallic Inclusions

Morphologies of typical inclusions found in Fe-C-Mn-Si-O-S-Ti-Mg-Al-N

Mn/Si

Mn/Si

+Ti

Mn/Si

/Ti

+Mg

Mn/Si

/Ti/Mg

+AlMnS

Mg-Ti-Al-O

MgO

1㎛

Mg-Ti-(Al)-OMnS

MgO

1㎛

MnS

Mg-Al-(Ti)-O

MgO2㎛

MgO

MgAl2O4

Mn

S

1㎛

MgAl2O4MnS

1㎛

Ti-Mg-Mn-O

MnS 2㎛

MnSMg-Ti-Mn-O

1㎛ 1㎛

Mg-Ti-Mn-O

MnS

MgO

MgO

MnS

MgO

1㎛

2㎛

Mn-Si-O

MnS

2㎛

Mn-Ti-O

Mn-Si-O

MnS2㎛

Mn-Ti-O

Mn-Si-O

MnS 1㎛

Ti-Mn-O

MnS1㎛

Ti-O

MnS

(a)

(f) (h) (i)

(j) (k) (l) (m) (n)

Concentration of additional alloying element

(d)(b) (c) (e)

(g)

Mn/Si

Mn/Si

+Ti

Mn/Si

/Ti

+Mg

Mn/Si

/Ti/Mg

+AlMnS

Mg-Ti-Al-O

MgO

1㎛

Mg-Ti-(Al)-OMnS

MgO

1㎛

MnS

Mg-Al-(Ti)-O

MgO2㎛

MnS

Mg-Al-(Ti)-O

MgO2㎛

MgO

MgAl2O4

Mn

S

1㎛

MgAl2O4MnS

1㎛

Ti-Mg-Mn-O

MnS 2㎛

Ti-Mg-Mn-O

MnS 2㎛

MnSMg-Ti-Mn-O

1㎛

MnSMg-Ti-Mn-O

1㎛ 1㎛

Mg-Ti-Mn-O

MnS

MgO

1㎛

Mg-Ti-Mn-O

MnS

MgO

MgO

MnS

MgO

1㎛

MgO

MnS

MgO

1㎛

2㎛

Mn-Si-O

MnS

2㎛

Mn-Si-O

MnS

2㎛

Mn-Ti-O

Mn-Si-O

MnS2㎛

Mn-Ti-O

Mn-Si-O

MnS 1㎛

Ti-Mn-O

MnS1㎛

Ti-O

MnS

(a)

(f) (h) (i)

(j) (k) (l) (m) (n)

Concentration of additional alloying element

(d)(b) (c) (e)

(g)

Fe-0.1C-0.0035S-1.45Mn-0.1Si

-0.015Ti-0.0025O-0.03N+Mg



2012

Evolution of Non-metallic Inclusions

(PB) (IL)

(MgO/Sp) (Sp)

(MgO)

Mg=2ppm 4

16

52

35

Thermodynamic Calculations

• Accurate prediction of inclusions phases

• Application to high strength steel design



2012

Montreal

2012

Inclusion evolution with temperature: Mn/Si/Ti steel

MS-c

SLAGA#1

SLAGA#1

SLAGA#1

ILMEA#1

ILMEA#1

Rhod

OlivA

PSEU

98.2769 Fe + 0.1 C + 1.5 Mn + 0.1 Si +

c:\Workshop\Equi0.res 3May11

T(C)

wt

pp

m

1000 1100 1200 1300 1400 1500 1600

0

100

200

300

400

500

600

Select all phases (pure solids and

solutions) with amount > 0

FToxid : oxide inclusions

FTmisc: FeLq, MnS solid (MS_c)

FSStel: solid steel phases (fcc, bcc)



2012

Montreal

2012

Wire

Inclusion (ex., alumina)

Crack Initiation

• Undeformable Inclusion should be removed

• Liquid phase is desirable at process

temperature (~1200oC)

Application to Tire-Cord Steel (Mn/Si deoxidation)

Tire-Cord Steel

Thin Sheet

Inclusion (ex., alumina)

Crack Initiation

Surface Quality Fe-36%Ni Invar Steel

0.15~0.38mm diameter

150µm thickness

Mn/Si Deoxidation



2012

Montreal

2012

MnO-Al2O3-SiO2 Phase Diagram

Target Inclusion

Composition

MnO Al2O

3Weight %

1890

1194

1249

1239

1527

1595

1180

1156

1135

1119

1465

1143

1166

1328

1251

1293

1465

Mn2SiO4

MnSiO3

MnAl2O4

Al6Si2O13

Mn2Al4Si5O18

Mn3Al2Si3O12

Corundum

1800

1700

1600

1500

1400

1300

2000

1900

18001

70016001500

1400

1300

1200

1400

1300

Galaxite

Manganosite

2 Liquids

Mullite

Rhodonite

Tephroite

1769

1702

1702

(1723)

(2054)(1842)

1600

Tridymite

Spessarti

te

(1890)(1347)

MnO/SiO2 = 0.5

MnO/SiO2 = 1.0

MnO/SiO2 = 2.0

1150

SiO2

Low liquidus

temperature region

(1100oC ~ 1200

oC)

Cristobalit

e

Cristobalite: SiO2

Tridymite: SiO2

Rhodonite: MnSiO3

Spessartite: Mn3Al2Si3O12

Tephroite: Mn2SiO4

Manganosite: MnOGalaxite: MnAl2O4

Corundum: Al2O3

Mullite: Al6Si2O13

MnO Al2O

3Weight %

1890

1194

1249

1239

1527

1595

1180

1156

1135

1119

1465

1143

1166

1328

1251

1293

1465

Mn2SiO4

MnSiO3

MnAl2O4

Al6Si2O13

Mn2Al4Si5O18

Mn3Al2Si3O12

Corundum

1800

1700

1600

1500

1400

1300

2000

1900

18001

70016001500

1400

1300

1200

1400

1300

Galaxite

Manganosite

2 Liquids

Mullite

Rhodonite

Tephroite

1769

1702

1702

(1723)

(2054)(1842)

1600

Tridymite

Spessarti

te

(1890)(1347)

MnO/SiO2 = 0.5

MnO/SiO2 = 1.0

MnO/SiO2 = 2.0

1150

SiO2

Low liquidus

temperature region

(1100oC ~ 1200

oC)

Cristobalit

e

Cristobalite: SiO2

Tridymite: SiO2

Rhodonite: MnSiO3

Spessartite: Mn3Al2Si3O12

Tephroite: Mn2SiO4

Manganosite: MnOGalaxite: MnAl2O4

Corundum: Al2O3

Mullite: Al6Si2O13

Jung et al., Metall. Mater. Trans. B, 2004, vol. 35B, pp. 259-268



2012

Montreal

2012

Inclusion composition with steel composition

Jung et al., Metall. Mater. Trans. B, 2004, vol. 35B, pp. 259-268

Kang and Lee, ISIJ Inter., 2004.

10

20

30

40

50

60

70

80

90

102030405060708090

10

20

30

40

50

60

70

80

90

SiO2

MnO Al2O3Weight %

wt%Mn / wt%Si = 9

10

52

1

0.5

0.2

0.1

wt%Mn / wt%Si = 1

wt%Mn / wt%Si = 0.1

T =1550oC

Liquid Oxide

L + MnO L + MnAl2O4

L + Al2O3

L + Mullite

L + SiO2

MnO/SiO2 = 1.0

Mn + Si = 1wt%



2012

Montreal

2012

Inclusion calculation in Mn/Si deoxidation

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

MnO Al2O3mass fraction

ASlag-liq + AMonoxide ASlag-liq + MnAl2O4(s)

ASlag-liq + M2O3(corundum)

ASlag-liq + Mullite


MnO - Al2O3 - SiO2

1600oC



2012

Montreal

2012


Calculation of the inclusion trajectory using Equilib

The compositions of Mn and Si are set based on the target Mn/Si ratio and Mn+Si content

Oxygen content should be controlled reasonably. If O is too high, Mn and Si will be largely

changed from original target composition after rxn with oxygen.



2012

Montreal

2012


Mn + Si + Al + O (Mn,Si,Al) oxide inclusion

After deoxidation, Mn ~ 0.5 and Si ~ 0.5

(Target steel composition: Mn/Si = 1 and Mn+Si = 1)

Extraction of slag composition



2012

Montreal

2012


Slag #1

(stable slag) Slag #2

(metastable or same as #1

except in case of stable miscibility gap)

Composition from Slag #1

A corner = wt%SiO2/100

B corner = (wt%MnO+Mn2O3+FeO+Fe2O3)/100

C corner = wt%Al2O3/100



2012

Montreal

2012


0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

SiO2

MnO Al2O3mass fraction

ASlag-liq + AMonoxide ASlag-liq + MnAl2O4(s)

ASlag-liq + M2O3(corundum)

ASlag-liq + Mullite


MnO - Al2O3 - SiO2

1600oC

10

20

30

40

50

60

70

80

90

102030405060708090

10

20

30

40

50

60

70

80

90

SiO2

Al2O3

Mn/Si = 10

5.0

2.01.0

0.5

Fe Liquid

[%Mn] + [%Si] = ~1.0

T = 1600oC

1.0

Kang and Lee [35]

SiO2

Al2O3

1200oC

liquidus

SiO2

MnO(+FeO) Al2O3

0.2

0.1

0.35

0.52

1.1

0.50

11.1

9.9

Ohta and Suito[34]

weight percent

Slag composition is slightly off

from phase diagram because the

actual slag is containing FetO

and Mn2O3 as well.

According to calculations,

mullite and Al2O3 are

forming subsequently

after slag



2012

Montreal

2012


Al2O3(SLAGA#1)

SiO2(SLAGA#1)

FeO(SLAGA#1)

Fe2O3(SLAGA#1)

MnO(SLAGA#1)

98.995 Fe + 0.5 Mn + 0.5 Si + <A> Al +

c:\Workshop\Equi0.res 3May11

weight % Al_FeLQ

we

igh

t %

0 0.0002 0.0004 0.0006 0.0008 0.001

0

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

Soluble Al vs. Inclusion composition



2012

Nozzle Clogging in Ti-bearing Al-killed steel

• Kawashima et al., CAMP-ISIJ (1991)

– Liquid Al-Ti-O (reoxidization) attached to Al2O3 inclusions

• Basu et al. ISIJ Int. (2004)

Significant difference of nozzle clogging of Ti-bearing steel from and Ti-free

steel is the existence of the Al-Ti-O inclusions covering Al2O3 core oxides.

Reoxidation in tundish (high SiO2 slags) causes the nozzle clogging.



2012

Inclusions generated by Reoxidation process

RH process after Ti addition (POSCO)

Doo et al. (2007)

Al2O3

Ti-Al-O hole

Reoxidation in Tundish

(high SiO2 slags)

Park et al. (2004)

Reoxidation in Tundish

Basu et al. (2004)

Ti/Al of outer layer = 1.0~1.5



2012

Inclusion causing nozzle clogging in Al-killed Ti bearing steel

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

mole fraction

corundum

TiO2 + L

ilmenite + Ti3O5

Ti3O5 + L

co

run

du

m +

L

+ ilmenite + L

ilmenite + Llo

g P

O2 =

-11

-12

-13

-14

Al2O3

Ti2O3 TiO2

+ A

l2 T

iO5 +

LAl2TiO5 + L

Al2O3

Ti2O3 TiO2

Al2O3

Ti2O3 TiO2

Al2O3

Ti2O3 TiO2

Al2O3

Ti2O3 TiO2

Al2O3

Ti2O3 TiO2

Al2O3

Ti2O3 TiO2

T = 1600oC

-10

Liquid

Magneli + L

coru

ndum

-9.0



2012

Calculated inclusion composition in Fe-Al-Ti-O liquid at 1600oC

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.10.20.30.40.50.60.70.80.9

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Al2O3

Ti2O3TiO2 + FeOmole fraction

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

Al2O3

Ti2O3

corundum

L

ilmenite + Ti3O5 + LTi3O5 + L

corundum + L+ ilmenite + L

ilmenite + L

Ti =

10p

pm

50

100

500

1000

Similar to Mn/Si

deoxidation calculations



2012

Newly calculated Inclusion diagram of Fe-Al-Ti-O system

Al2O3

Ti2O3

Ti3O5

56[wt ppm O]

20

15

12

10

50

30

20

15

12

80

30

810 =4.5 ppm

50T = 1600

oC

Liquid

log [wt% Al]

log

[w

t% T

i]

-4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Existence of Liquid

Al2O3-Ti2O3-TiO2

phase at 1600oC

Al deoxidation + Ti addition

Reoxidation

(Nozzle Clogging)



2012

Al killed Ti bearing steel



2012

Al killed Ti bearing steel



2012

Reoxidation of Al killed Ti bearing steel


“Recycle all streams”

• you don’t have to save the stream one by one. But the results

will be used only one time because it is not saved under

special stream name.

• Convenient option when you want to do one calculation


2012



Addition of oxygen to simulation

reoxidation phenomena.

Real source of oxygen could be

high SiO2 slag or refractories


2012



SLAGA#1

SLAGA#1

SLAGA#1

CORU#1

CORU#1

CORU#1

CORU#1

100% [Rc_Fe-liq] + 100% [Rc_M2O3(Corundum)] + <A> O2

C:\Slag-Steel-Inclusions\Equi0.res 25Sep12

Alpha

gra

m

0.00 0.01 0.02 0.03 0.04 0.05

0.00

0.05

0.10

0.15

0.20

+ 0.12253 gram ASlag-liq#1

(0.12253 gram, 1.1558E-03 mol)

(1600 C, 1 atm, a=1.0000)

( 33.379 wt.% Al2O3 FToxid

+ 0.17724 wt.% SiO2 FToxid

+ 0.83830 wt.% FeO FToxid

+ 1.1051E-03 wt.% Fe2O3 FToxid

+ 1.9943 wt.% MnO FToxid

+ 40.135 wt.% Ti2O3 FToxid

+ 23.475 wt.% TiO2 FToxid

+ 1.0928E-03 wt.% Mn2O3 FToxid)

This calculation shows that mixed inclusion of Al2O3(s) and liquid (Al2O3-TiO2-Ti2O3)

can be formed by the reoxidation of Al-killed Ti bearing steel.

Nozzle clogging.


2012

TiN formation in Al killed and Ti bearing steel


Original steel composition at 1600C: high N and high Ti may form TIN


2012

TiN formation in Al killed and Ti bearing steel


TiN(s)

CORU#1CORU#1CORU#1CORU#1

100% [Rc_Fe-liq] + 100% [Rc_M2O3(Corundum)]


T(C)

gra

m

1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600

0.00

0.05

0.10

TiN(s) CORU#1CORU#1CORU#1CORU#1

BC

C

FeL

Q

100% [Rc_Fe-liq] + 100% [Rc_M2O3(Corundum)]


T(C)

gra

m

1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600

0

10

20

30

40

50

60

70

80

90

100

Liquid steel

+ BCC Liquid steel

During the solidification,

a large amount of TiN can be formed.


2012

Montreal

2012

Inclusion diagram: Fe-Al-O, Al deoxidation

(1): draw rectangular diagram



2012

Montreal

2012


(2): change X- and Y-axis lower limit.

(3): change linear scale to log scale.

(3): change linear scale to log scale.

(2): change X- and Y-axis lower limit.

“After changing the axes to log

scale, move all curves to +2 in

linear scale“



2012

Montreal

2012


Fe-liq + M2O3(Corundum)

Fe-liq

Fe - Al - O

1600oC

log [wt% Al]

log

[w

t% O

]

-4 -3.5 -3 -2.5 -2 -1.5 -1 -.5 0

-4

-3.5

-3

-2.5

-2

-1.5

-1(4) Editing of title of x- and y-axis



2012

Montreal

2012

M2O3(corundum) + Fe-liq

Fe-liq

Fe - Al - O - Ti

1600oC, mass O/(Fe+Al+O+Ti) = 5E-6

wt% Al

wt%

Ti

-5 -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0

-3

-2.7

-2.4

-2.1

-1.8

-1.5

-1.2

-0.9

-0.6

-0.3

0

log wt% Al

log w

t% T

i

Inclusion diagram: Fe-Al-Ti-O, Al/Ti deoxidation

Fe-liq + M2O3(Corundum)

Fe-liq

Fe - Al - O

1600oC

log [wt% Al]

log

[w

t% O

]

-4 -3.5 -3 -2.5 -2 -1.5 -1 -.5 0

-4

-3.5

-3

-2.5

-2

-1.5

-1



2012

Montreal

2012


Fe-liq

Fe-liq

Pseudobrookite + Fe-liq

Pseudobrookite + Fe-liq

BIlmenite + Fe-liq

Fe - Al - O - Ti


log wt% Al

log w

t% T

i

-5 -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0

-3

-2.7

-2.4

-2.1

-1.8

-1.5

-1.2

-0.9

-0.6

-0.3

0

Al2O3

Ilmenite (Ti2O3-rich phase)

Ti3O5

56[wt ppm O]

201512

10

50

30

20

1512

80

30

810 =4.5 ppm

50T = 1600

oC

Liquid

log [wt% Al]

log

[w

t% T

i]

-4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0


Fe-liq

Fe - Al - O - Ti


wt% Al

wt%

Ti

-5 -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0

-3

-2.7

-2.4

-2.1

-1.8

-1.5

-1.2

-0.9

-0.6

-0.3

0

log wt% Al

log w

t% T

i Inclusion diagram: Fe-Al-Ti-O, Al/Ti deoxidation

1) Change oxygen content and calculate similar diagram

2) Superimpose all the diagram together

3) Calculate the phase boundaries from Equilib (or simply

connect boundaries in the calculated diagram)

Iso oxygen 5ppm line



2012

Montreal

2012

Inclusion after Mn/Si deoxidation



2012

Montreal


Application: Solidification of slag and steel

Scheil Cooling calculations


2012

T1

T2

T3

Te

T1

T2

T3

T<Te

L1

L2 L3

L2

L3

L1

Scheil

Cooling

Equilib.

Cooling

Equilibrium cooling and Scheil cooling

Scheil Cooling

Solidification microstructure



2012

Montreal

2012

Equilibrium cooling of the CaO-SiO2-Al2O3-MgO slag

Equilibrium solidification of slag



2012

Montreal

2012

Equilibrium solidification of slag: plot amount vs. temperature

2

1

3

4

5



2012

Montreal

2012

Ca3MgSi2O8(s) Ca3MgSi2O8(s) Ca3MgSi2O8(s)

SLAGA#1

SPINA#1 SPINA#1 SPINA#1

SPINA#1

Mel_ Mel_ Mel_

40 CaO + 10 MgO + 20 Al2O3 + 30 SiO2


T(C)

gra

m

1000 1100 1200 1300 1400 1500 1600

0

020

040

060

080

100


Equilibrium solidification is completed at ~ 1410oC



2012

Montreal

2012

Scheil cooling solidification of slag

Scheil cooling of the CaO-SiO2-Al2O3-MgO slag

Scheil cooling temperature setup:

(initial_T final_T)



2012

Montreal

2012

Ca3MgSi2O8(s)Ca3MgSi2O8(s)

SLAGA#1SLAGA#1

SLAGA#1

SLAGA#1SPINA#1

SPINA#1SPINA#1

Mel_

Mel_

OlivA#1

40 CaO + 10 MgO + 20 Al2O3 + 30 SiO2


T(C)

gra

m

1225 1275 1325 1375 1425 1475 1525 1575

0

020

040

060

080

100


Scheil cooling solidification is completed at ~ 1320oC



2012

Montreal

2012

Solidification of mould flux


Using ‘CON1’ database


2012

Equilibrium cooling of Fe-20Mn-1C-1Al TWIP steel

Equilibrium solidification of steel: TWIP steel



2012

CEME

CEME

FCC

FCCFCC FCC

FCC

FE-L

78 Fe + 20 Mn + C + Al

T(C)

gra

m

600 700 800 900 1000 1100 1200 1300 1400

0

10

20

30

40

50

60

70

80

90

100

110

Equilibrium solidification of steel: TWIP steel



2012

Scheil cooling solidification of steel: TWIP steel

Scheil cooling of Fe-20Mn-1C-1Al TWIP steel



2012

FCC

FCC

FCC

FCC

FCC

FE-L

FE-L

FE-L

FE-L

FE-L

78 Fe + 20 Mn + C + Al

T(C)

gra

m

600 700 800 900 1000 1100 1200 1300 1400

0

10

20

30

40

50

60

70

80

90

100

110

Scheil solidification of steel: TWIP steel

Solidification is completed at ~ 1075oC which is

almost 100oC lower than equilibrium calculation.



2012

Montreal


Application: Refractory design

Chemical stability

Thermal stability


2012

Montreal

2012

Simple counter-cross inter-diffusion calculation: <A> option

Counter-cross inter-diffusion reactions at interface can be simulated with the

<A> option in Equilib. This assumes the diffusivities of all components in both

materials are the same.

Materials #1 Materials #2

Materials #2 Materials #1

concentr

ation

<A> reactants #1 + <1-A> reactants #2



2012

Montreal


Counter-cross reaction: refractory / slag

Slag

60%CaO-40%SiO2

Refractory

95%Al2O3-5%MgO


2012

Montreal


Counter-cross reaction: refractory / slag

Al2O3(s4) CaMg2Al16O27(s)

Ca2Mg2Al28O46(s)

Ca2Mg2Al28O46(s)

SLAGA#1

SLAGA#1

SLAGA#1 SLAGA#1

<0.6A> CaO + <0.4A> SiO2 + <0.95-0.95A> Al2O3 + <0.05-0.05A> MgO

c:\Workshop\AlloyDesign\Equi0.res 9May10

Alpha

gra

m

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0.0

0.2

0.4

0.6

0.8

1.0


2012

Montreal

2012

[Sla

g]

[Refr

acto

ry]

Al2O3

FeO

MgO

Cr2O3

(1-x) refractory + x slag (by weight)

com

po

siti

on

of

spin

el,

wt%

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1

0

10

20

30

40

50

60

70

80

90

100

[Refractory]

[Slag]

Spinel

Periclase

[Sla

g]

[Refr

acto

ry] Slag

Periclase

Spinel


rela

tiv

e a

mo

un

t o

f ea

ch p

ha

se,

wt%

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1

0

10

20

30

40

50

60

70

80

90

100

Al2O3

FeO

MgO

Cr2O3

[Sla

g]

[Refr

acto

ry]


com

po

siti

on

of

per

icla

se,

wt%

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1

0

10

20

30

40

50

60

70

80

90

100

[Sla

g]

[Refr

acto

ry]

CaO

SiO2

Al2O3

MgO

FeOCr2O3


com

po

siti

on

of

sla

g,

wt%

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1

0

10

20

30

40

50

60

70

slag

spinel

periclase

refractories; 58MgO-6.5Al2O3-21 Cr2O3-13.5FeO

slag; 50CaO-40SiO2-10Al2O3 (in wt%)

Counter-cross reaction: Refractories in VOD

T=1650oC

Jung et al., Taikabutsu, vol. 56, 2004, pp. 382-386.



2012

RH Vessel Refractory

Snorkel

RH Vessel

Ladle

O2 Lance

RH OB

• High amount of oxygen blowing

• Increase of Ferro-alloy (Al, Si, Mn, etc) addition

→ More severe local corrosion of RH vessel refractory

Normal corrosion

Abnormally severe corrosion

Flow pattern in RH

CFD model



2012

Quite enough thermodynamic database

(gas, molten steel, slag, refractory, etc…)

Write kinetic process using Macro :

input/output to Excel spread sheet

Reaction zone 1

Reaction zone 2

Reaction zone 3

Heat & Mass balance !!

…… Van Ende et al: ‘A Kinetic Model for the Ruhrstahl Heraeus (RH)

Degassing Process’, Metall. Mater. Trans. B, 2011, p. 477

Concept for RH process simulation modeling



2012

RH Vessel Refractory


Predicted slag composition in RH

vessel from RH process simulation

M.-K. Cho, M.-A. Van Ende, T.-H. Eun and I.-H. Jung, “Investigation of slag-refractory interactions for the

Ruhrstahl Heraeus (RH) vacuum degassing process in steelmaking”, J. Eur. Ceram. Soc., 2012, 32,1503-1517.

Experimental and calculation conditions

F1,F2 C1,C2


2012

Refractory Finger tests at 1600oC



2012

Thermodynamic Calculations: Refractories – Slag Interactions



2012

Ladle Glaze formation

Dipping time: 120 sec CaO SiO2 Al2O3 MgO

54.06 10.47 26.24 9.23

Slag composition (wt.%)

CaO SiO2 Al2O3 MgO

2.35 0.76 88.06 8.35

Refractory composition (wt.%)

As-received Dipped for 120 sec Ferrous Processing 178


2012

Glazed Refractory

Glaze



2012

Montreal

2012

Glaze (Reaction product of slag and refractory)

Slag

Spinel

CaAl12O19

CaAl4O7

Al2

O3

x slag + (1-x) refractory

ph

ase

dis

trib

uti

on

(w

t%)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

10

20

30

40

50

60

70

80

90

100

Al2O3

CaO

SiO2

MgO

x slag + (1-x) refractory

sla

g c

om

po

siti

on

(w

t %

)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

10

20

30

40

50

60

70

spinel islands

Glaze composition (glass)

CaO SiO2 Al2O3 MgO

35.8 6.6 51.1 6.5

Glaze area: glass + spinel

Original refractory Ladle slag



2012

Montreal

2012

Equilibrium stability of 20MgO-78Al2O3-2CaO refractories

Equilibrium stability calculations with temperature: refractories



2012

Montreal

2012

CaAl4O7(s)

CaAl4O7(s)

CaMg2Al16O27(s) CaMg2Al16O27(s) CaMg2Al16O27(s)

CaMg2Al16O27(s)

SPINA SPINA SPINA

SPINA

SLAGA#1SLAGA#1

2 CaO + <A> MgO + <98-A> Al2O3


T(C)

gra

m

1200 1300 1400 1500 1600 1700 1800

0

10

20

30

40

50

60

70

80

90

Equilibrium stability calculations with temperature: refractories

The refractory is mechanically unstable above 1600oC:

- considerable volume change due to the significant change in phase distribution

The refractory cannot be used above 1690oC:

- significant amount of liquid phase formation



2012

Montreal

2012

Thermal Stability test of Refractories

wt% REF-1 2 3 4 5 6

Al2O3 88 60 11 4 0.5 0.5

MgO 9 38 58 61 89 75

CaO 2 2 0.9 0.7

Cr2O3 20 29

Fe2O3 8.8 4.8

SiO2 1.6 0.4 0.5 1.2

C 7 17

Al 2 4

MgO

Spinel

SlagCa3MgAl4O10

(gram) 60 Al2O3 + 38 MgO + 2 CaO

Temperature (C)

ph

ase

dis

trib

uti

on

(w

t%)

1200 1300 1400 1500 1600 1700 1800 1900

0

10

20

30

40

50

60

70

80

90

Spinel

CaMg2Al16O27

Al2O3

Ca2Mg2Al28O46

CaAl12O19

(gram) 88 Al2O3 + 9 MgO + 2 CaO

Temperature (C)

ph

ase

dis

trib

uti

on

(w

t%)

1200 1300 1400 1500 1600 1700 1800 1900

0

10

20

30

40

50

60

70

80

90

REF-1 REF-2



2012

Thermal Stability test of Refractories

CaMgSiO4

Mg2SiO4

Slag

Spinel

MgO

(gram) 11 Al2O3 + 58 MgO + 0.9 CaO + 20 Cr2O3 + 8.8 Fe2O3 + 1.6 SiO2

Temperature (C)

ph

ase

dis

trib

uti

on

(w

t%)

1200 1300 1400 1500 1600 1700 1800 1900

0

10

20

30

40

50

60

70

80

90

Slag

Spinel

MgO

a-Ca2SiO4a'Ca2SiO4

(gram) 4 Al2O3 + 61 MgO + 0.7 CaO + 29 Cr2O3 + 4.8 Fe2O3 + 0.4 SiO2

Temperature (C)

ph

ase

dis

trib

uti

on

(w

t%)

1200 1300 1400 1500 1600 1700 1800 1900

0

10

20

30

40

50

60

70

80

90

C

MgO

Al4C3Spinel

(gram) 0.5 Al2O3 + 89 MgO + 0.5 SiO2 + 7 C + 2 Al

Temperature (C)

ph

ase

dis

trib

uti

on

(w

t%)

1200 1300 1400 1500 1600 1700 1800 1900

0

10

20

30

40

50

60

70

80

90

REF-5

REF-3 REF-4

Depending on the refractory compositions,

the refractory components can vary drastically.

Formation of liquid

Stability of refractory

Change in MgO/Spinel fraction

Mechanical wear resistance

Volume change



2012

Refractory – Liquid Inclusion Interactions


Stopper Head

SEN Collar

Inner side/mouth

of SEN

Stopper (Al2O3-C)

Corroded area

Inner side of SEN

SEN (submerged entry nozzle)

melt

M.-K. Cho and I.-H. Jung, “Corrosion of nozzle refractories by liquid inclusion in high oxygen steels”,

ISIJ Inter. 2012, vol. 52, pp. 1289-1296.


2012



Ple

ase s

ee t

he d

eta

ils in t

he I

SIJ

paper


2012



Please see the details in the ISIJ paper


2012



Ple

ase s

ee t

he d

eta

ils in t

he I

SIJ

paper

Relative Stability of the refractories against liquid MnO-SiO2 type inclusion


2012

Refractory-Steel Interaction



2012

Refractory-Steel Interaction


FeLQ FeLQ FeLQ FeLQ

SPINA#1

SPINA#1

SPINA#1

SPINA#1

MeO_A

MeO_A

MeO_A

CO

RU

#1

95 Fe + 4 Mn + Si + <100-100A> MgO +


Alpha

gra

m

0.0 0.2 0.4 0.6 0.8 1.0

0

20

40

60

80

100

Mn_FeLQ Mn_FeLQ Mn_FeLQ Mn_FeLQ

Si_FeLQ Si_FeLQ Si_FeLQ Si_FeLQ

Al_FeLQAl_FeLQ Al_FeLQ Al_FeLQMg_FeLQ Mg_FeLQ Mg_FeLQ Mg_FeLQO_FeLQ O_FeLQ O_FeLQ O_FeLQ

95 Fe + 4 Mn + Si + <100-100A> MgO +


Alpha

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Change in steel composition

Change in the amount of phases

<A> Al2O3 + <1-A> Al2O3

<A> Al2O3 + <1-A> Al2O3


2012

85%Mn-15%Fe melt

Refractories

1g Mn-Fe melt + 1g refractory (MgO-Cr2O3)

Melt / refractory reactions simulation

Liquid

Spinel (MgCr2O4-MnCr2O4)

(MgO-MnO)

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Cr2O3

<A> MgO + <1-A> Cr2O3

gra

m

0.0 0.2 0.4 0.6 0.8 1.0

0

0.2

0.4

0.6

0.8

1

1.2

MgO

MnO

Cr2O3

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Cr2O3

<A>MgO + <1-A>Cr2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Cr2O3 MgCr2O4 MgO

(Spinel)

(MgO-MnO)

MgCr2O4

MnCr2O4

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Cr2O3

<A> MgO + <1-A> Cr2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Fe

MnCr

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Cr2O3

<A> MgO + <1-A> Cr2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Steel

High Mn-Fe melt storage for TWIP Steel production



2012

LIQU

(MgO-MnO)

Corun

dum

(Al2

O3)

Spinel (MgAl2O

4-MnAl2O

4)

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Al2O3

<A> MgO + <1-A> Al2O3

gra

m

0.0 0.2 0.4 0.6 0.8 1.0

0

0.2

0.4

0.6

0.8

1

MgO

MnO

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Al2O3

<A> MgO + <1-A> Al2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Fe

Mn

Al

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Al2O3

<A> MgO + <1-A> Al2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

MgAl2O4

MnAl2O4

Al8O12

0.15 Fe + 0.85 Mn + <A> MgO + <1-A> Al2O3

<A> MgO + <1-A> Al2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Al2O3 MgAl2O4 MgO

MgO

Spinel Steel

1g Mn-Fe melt + 1g refractory (MgO-Al2O3)

High Mn-Fe melt storage for TWIP Steel production



2012

Fe

Mn

Al

<77.9B> Fe + <20B> Mn + <1.5B> Al + <0.6B> C +

<A> MgO + <1-A> Al2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Liquid

MgO

Al2 O

3

MgAl2 O

4 -MnAl2 O

4

<77.9B> Fe + <20B> Mn + <1.5B> Al + <0.6B> C +

<A> MgO + <1-A> Al2O3g

ram

0.0 0.2 0.4 0.6 0.8 1.0

0

0.2

0.4

0.6

0.8

1

Twip steel

Refractories

Refractory for TWIP steel: Fe-20%Mn-1.5%Al-0.6%C

T = 1500oC

Steel

MgO-Al2O3 type: Very stable refractory



2012

Twip steel

Refractories

Refractory for TWIP steel: Fe-20%Mn-1.5%Al-0.6%C

T = 1500oC

Steel

MgO-Cr2O3 type: less stable

Cr pickup

Al loss

Fe

Mn

Cr

<77.9B> Fe + <20B> Mn + <1.5B> Al + <0.6B> C +

<A> MgO + <1-A> Cr2O3

we

igh

t %

0.0 0.2 0.4 0.6 0.8 1.0

0

10

20

30

40

50

60

70

80

90

100

Steel

MgC

r2 O

4 -MnC

r2 O

4M

gO-M

nO-s

mall C

r 2O 3

MgAl2O4-MnAl2O4

Cr

2 O3 -A

l2 O3

<77.9B> Fe + <20B> Mn + <1.5B> Al + <0.6B> C +

<A> MgO + <1-A> Cr2O3

gra

m

0.0 0.2 0.4 0.6 0.8 1.0

0

0.2

0.4

0.6

0.8

1



2012

Enthalpy of slags

• When slag forms from pure oxides, a certain

amount of heat (enthalpy) is needed.

• When slag is cooled down, a certain amount of

heat should be extracted.

• FactSage Phase diagram: Enthalpy diagram



2012

Heat required to form and increase temperature of slag


Pure FeO(s) is not in FToxid compound database

(Strictly speaking, FeO is non-stoichiometric

compound so it is in MeO solution)

Initial condition

FactSage can used two variables, <A> and <B>

<A> can be really varied and <B> should be constant

H = Hfinal – Hinitial

So initial conditions(phase,T,P) should be defined



Final condition

H = Hfinal – Hinitial

This is the heat we add to increase the

temperature up to 1600oC.

That is, H = Hslag at 1600C – Hinitial oxides at 25C

This is the enthalpy of the final

products at 1600oC

Heat required to form slag and increase the temperature of slag


2012

Heat required to form slag and increase the temperature of slag


<A> MgO + <1-A-B> FeO + <B> SiO2

Alpha

De

lta

H(J

)

0.0 0.1 0.2 0.3 0.4 0.5

1475

1525

1575

1625

1675

1725

1775

1825

1875

1925

Fe(s) Fe(s) Fe(s) Fe(s)

SLAGA#1 SLAGA#1

SLAGA#1

SLAGA#1

MeO_A

OlivA

OlivA

<A> MgO + <1-A-B> FeO + <B> SiO2


Alpha

gra

m

0.0 0.1 0.2 0.3 0.4 0.5

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

slag

Sla

g+

Oliv

ine

Sla

g+

Oliv

ine+

MeO

Oliv

ine+

MeO



Enthalpy diagram: phase change with H



• Only X-Y type diagram allowed.

• Y axis should be Enthalpy (H-HTmin).

• Hinitial (HTmin) is the enthalpy of products stable at Tmin. For example, Fe2SiO4

(fayalite_olivine) and SiO2 are stable at 0% MgO and 30% SiO2 instead of FeO and

SiO2.

30%SiO2

Tinitial

Iso-Temperature

Enthalpy diagram option



2012



If we increase the temperature of the mixture of (Monoxide + olivine) at 20 wt % MgO and 30 wt % SiO2

from 25 oC to 1625 oC, liquid slag is forming and the amount of heat required for this is about 2250 J/g.

125 oC

225 oC

325 oC

425 oC

525 oC

625 oC

725 oC

825 oC

925 oC

1025 oC

1125 oC

1225 oC

1325 oC

1425 oC

1525 oC

1625 oC

1725 oC

1825 oC

2025 oC2125

oC2225

oC2325

oC2425

oC

AMonoxide + AMonoxide#2 + AOlivine

AMonoxide + AOlivine

ASlag-liq + AMonoxide + AOlivine


ASlag-liq


AOlivine + SiO2(s)

AOlivine + SiO2(s2)

AOlivine + SiO2(s4)

MgO - FeO - SiO2

SiO2/(MgO+FeO+SiO

2) (g/g) = 0.3, 1 atm

MgO/(MgO+FeO+SiO2) (g/g)

H -

H25 C

(J/g

)

0 0.1 0.2 0.3 0.4 0.5 0.6

0

500

1000

1500

2000

2500

3000

If w

e h

ea

t t

he

mix

ture

of (M

on

oxid

e +

oliv

ine

) a

t 3

0 w

t %

Mg

O a

nd

30

wt

% S

iO2

fro

m 2

5 o

C b

y 1

50

0 J

/g, th

e

mix

ture

be

co

me

s m

ixtu

re o

f (liq

uid

sla

g +

oliv

ine

) a

t

about 1425 o

C.


2012



125 oC

225 oC

325 oC

425 oC

525 oC

625 oC

725 oC

825 oC

925 oC

1025 oC

1125 oC

1225 oC

1325 oC

1425 oC

1525 oC

1625 oC

1725 oC

1825 oC

1925 oC2025

oC2125

oC2225

oC2325

oC

Orthopyroxene + AOlivine

AMonoxide + AOlivine


ASlag-liq

ASlag-liq + AOlivine + SiO2(s4)

ASlag-liq + AClinopyroxene + AOlivine

AOlivine + SiO2(s4)

ASlag-liq + AMonoxide + AOlivine

MgO - FeO - SiO2

SiO2/(MgO+FeO+SiO

2) (g/g) = 0.4, 1 atm

MgO/(MgO+FeO+SiO2) (g/g)

H -

H25 C

(J

/g)

0 0.1 0.2 0.3 0.4 0.5

0

500

1000

1500

2000

2500

3000


2012

Montreal

2012

Oxygen partial pressure control using Dew-point control

N2-5%H2

Ice(H2O(s)), T= -30°C

PO2=?

Oxidation ?

H2 + 1/2O2 = H2O

Annealing T= 800°C

Hot Dip Galvanizing

Cold worked at 300 °C

Dew point



2012

Montreal

2012

We should select real gas to obtain

accurate Gibbs energy and volume

fraction of gas at low temperature

and high pressure.

N2-H2 gas with -30C dew point



2012

Montreal

2012

We will heat this gas at 800°C using

stream file.




2012

Montreal

2012

Creating stream file




2012

Montreal

2012

Final partial pressure of oxygen

N2-H2 gas with -30oC dew point 800oC



2012

Montreal

2012

Dew Point = 0

o C

-10o C -20

o C-30

0 C-40

o C-50

0 C

TemperatureoC

log

PO

2, b

ar

500 600 700 800 900 1000 1100 1200

-35-34

-33

-32

-31

-30

-29

-28

-27

-26

-25

-24

-23

-22

-21

-20

-19

-18

-17

-16

-15

Dew points – PO2/T Relationship

95%N2,5%H2

Dew Point 0o C

-100 C

-20o C

-30o C

-40o C

-500 C

Temperature0C

log p

O2,b

ar

500 600 700 800 900 1000 1100 1200

-35-34

-33

-32

-31

-30

-29

-28

-27

-26

-25

-24

-23

-22

-21

-20

-19

-18

-17

-16

-1590%N2,10%H2



2012

Montreal

2012

Phase diagram PO2 – T: Oxidation of Fe-1%Mn-1%Si



2012

Montreal

2012

BCC_A2

BCC_A2 + FCC(c,n)

FCC(c,n)

Rhodonite + BCC_A2 + SiO2(s2)

Rhodonite + BCC_A2 + SiO2(s)

Rhodonite + BCC_A2 + SiO2(s4)

Rhodonite + FCC(c,n) + SiO2(s4)

AOlivine + BCC_A2

AOlivine + BSpinel

Rhodonite + BCC_A2

Rhodonite + BCC_A2

O2 - Fe - Mn - Si

mass Mn/(Fe+Mn+Si) = 0.01, mass Si/(Fe+Mn+Si) = 0.01

T(C)

log

10(p

(O2))

(atm

)

500 600 700 800 900 1000

-40

-36

-32

-28

-24

-20



2012

Montreal

2012

FCC + BCC

FC

C +

BC

C +

SiO

2

FCC + BCC + SiO2 + MnSiO3

FCC + BCC + MnSiO 3

FCC + BCC + Mn2SiO4

FCC + BCC + MnSiO3 + Mn2SiO4

Fe - C - Mn - Si - O2

800oC, p(O

2) = 10

-27.5 bar, C = 0.1%

wt% Mn

wt%

Si

0.0 0.5 1.0 1.5 2.0

0.0

0.5

1.0

1.5

2.0

Drawing of the diagram:

1) Collect all blue/red/green lines at different PO2 and superimpose them in one diagram.

2) The boundary of each color line (different phase) is the phase boundary of the primary

oxide phase in the diagram.

EX17-3. Primary oxide formation diagram



2012

Montreal

2012

Fe-Mn-Si at PO2=10-28atm, T=800°C



2012

Montreal

2012

Boundaries for oxide phase



2012

Montreal

2012

<BCC + SiO2>

<BCC

+ MnSiO3>

wt %Mn

wt

%S

i

0.0 0.5 1.0 1.5 2.0 2.5 3.00.0

0.5

1.0

1.5

2.0

2.5

3.0

<BCC +FCC

+ MnSiO3>

<BCC +FCC

+ Mn2SiO4>

(A)(B)

(C)

Mn = 0.5

Si = 1.5

Primary oxidation Secondary oxidation

Mn = 0.5

Si = 1.0

SiO2 formation

Si depletion

in metal

SiO2+MnSiO3 formationSiO2

MnSiO3

<BCC + SiO2>

<BCC

+ MnSiO3>

wt %Mn

wt

%S

i

0.0 0.5 1.0 1.5 2.0 2.5 3.00.0

0.5

1.0

1.5

2.0

2.5

3.0

<BCC +FCC

+ MnSiO3>

<BCC +FCC

+ Mn2SiO4>

(A)(B)

(C)

Mn = 0.5

Si = 1.5

Primary oxidation Secondary oxidation

Mn = 0.5

Si = 1.5

SiO2 formation

Si depletion

in metal

SiO2+MnSiO3 formationSiO2

MnSiO3

Primary and Secondary Oxidations



2012

Montreal

2012

Oxidation phase diagram of the Fe-0.002%C-Mn-Si steel at 800oC

Oxidation phase diagram



2012

Slag/Steel/Inclusion Reactions


Slag

Steel

Inclusion

• In FactSage, if we put slag, steel and non-metallic inclusion

together and do calculations, it is impossible to distinguish

the slag and non-metallic inclusion phase.

• Theoretically, the slag and inclusion composition should be

identical if the entire system is in equilibrium. However, the

inclusion typically formed by the deoxidation of molten steel

take a time to be completely in equilibration with molten

slag.

• The only option to see the interaction between slag and

inclusion is to do two separate calculations, ‘Slag/Steel’ and

‘Steel/Inclusion’, and Steel can be shared between the

calculations. Therefore, the influence of Slag to Inclusion

chemistry can be calculated indirectly through the change of

Steel chemistry.

• In this calculations, the molten steel after the reaction with

molten slag should be stored as a mixture (stream) for the

input for next calculations with inclusion.

• Or, the calculations can be performed using the FactSage

macro processing simulation.


2012

Montreal

2012

SiO2( + 15%Al2O3)

CaO( + 15%Al2O3) MnO( + 15%Al2O3)Weight percent

1531

1291

1290

1667

1464

1274

1151

1573

Monoxide

Ca2SiO4 s.s.

Ca2Al2SiO7

Wollastonite

CaAl2Si2O8

SiO2

Al6Si4O13

Liquid Slag

Mn3Al2Si3O12

Ca3Si2O7

2300

22002000

1800

1600

1400

1150

1400

1200

1150

1150

1600

1020304050607080

10

20

30

40

50

60

70

80

80

70

60

50

40

30

20

10

([Mn]+[Si]) = 1wt%

1550oC

[C] = 0.7wt%

Mn/Si = 2.0

1200

Top-Slag Composition

55CaO-15Al2O3–30SiO2 (wt%)

Slag

Steel

Inclusion

Modification of inclusion in LF by interaction with top slag




Slag/Steel/Inclusion Reaction: Macro processing Input Excel file

Slag

Steel

Inclusion

(1)

(2)

T = 1600C

10 times iterations for (1) and (2) rxns.

System temperature

Relative amount is important for the change of

inclusion chemistry

Macro process files will

be provided separately



Slag/Steel/Inclusion Reaction: Macro processing Input Excel file


2012

Reoxidation of Al killed Ti bearing steel: macro-processing


Ladle slag with 5% FeO

Reoxidation by high FeO ladle slag (for example, just after RH process)


2012



Solid Al2O3 form after deoxidation.

Then, it is changed to liquid inclusion

with reoxidation by the slag.

The liquid inlcusion is composed mainly

Al2O3-TiO2-Ti2O3-MgO in early stage

and the CaO content in the liquid

inclusion is increasing with time.


2012



Tundish slag with 40% SiO2

Reoxidation by high SiO2 tundish slag (in Tundish)


2012



Solid Al2O3 form after deoxidation.

Then, it is changed to liquid inclusion

with reoxidation by the slag (more slowly

changed than the previous case).

The liquid inlcusion is composed mainly

Al2O3-TiO2-Ti2O3-MgO (less MgO than

the previous case) in early stage and

the CaO content in the liquid inclusion is

increasing with time. Ti2O3 level is

higher than previous case


2012

Montreal

2012

Viscosity Calculation: S+L mixtures (Einstein-Roscoe Eq.)


Einstein-Roscoe Equation (one of the most well-accepted

equation of viscosity for solid+liquid mixture)

Viscosity (solid+liquid mixture) Viscosity(liquid) (1 solid fraction)-2.5

Original Einstein-Roscoe equation use ‘volume fraction of solid’

instead of ‘solid fraction’ and correction term for morphology,

but all these values are not very well-known for general solids,

we can simply use the solid fraction (wt fraction) for this

equation as approximation.

This value can be calculated using “Equilib” module at

given system composition and temperature (Step-1).

Viscosity of liquid slag can be

calculated from “Viscosity”

module from slag composition

calculated from “Equilib” (Step-2)


2012

Montreal

2012

Viscosity Calculations “Step-1”: Composition of liquid slag



2012

Montreal

2012

Viscosity Calculations “Step-2”: Viscosity of liquid slag


Composition of liquid

slag from Equilib

Take these results

for next step

“Melts” database is for liquid slag


2012

Montreal

2012

Viscosity Calculations “Step-3”: Liquid + Solid mixture


Amount

of slag

Amount of solids

(100-amount of liquid)

Step-2

Einstein-Roscoe

Eq.


2012

Montreal

2012

Steelmaking Process: Thermodynamic Database

Thermodynamic Database Development for Steelmaking process

Database for De – P Slag / Flux development (2009~ 2014) • CaO-FetO-SiO2-MgO-MnO-Na2O-Al2O3-P2O5-CaF2 database • Slag / Solid phases • Experiment for phase diagrams • for the applications to Hot metal treatment and Basic Oxygen Furnace process

Database for Steel refining slag and Casting mould flux containing Fluorine (CaF2) (2009~2014) • CaO-MgO-Al2O3-SiO2-Na2O-Li2O-F (CaF2, NaF, LiF) database • Slag / Solid phases • Experiment for phase diagrams • for the applications to the optimization of mould flux and CaF2 containing flux

Steelmaking consortium project (2009 ~ 2014) with the support of

Documents

Ferrous Processing