Ferromanganese research in Norway

� Introduction; Me, NTNU and SINTEF

� Manganese research at NTNU/SINTEF

1

FeMn-S.Bunkholt 2007 SiMn-S.Bunkholt 2007

Prof. Merete TangstadNorwegian University of Science and TechnologyDepartment of Material Science and Engineering

� Department of Material Science and Engineering, NTNU (since 2004)

� Eramet 2000-2004, R&D

� Elkem 1989-2000, R&D and Furnace Metallurgist

� PhD at NTNU in Cokebed Relations

2

� FeMn/SiMn furnace operation

� Fundamentals of the Si production

� Feedstock to solar cell Si production

Norwegian University of Science and Technology - NTNU

3

FACTSFACTS

NTNU key figures 2008

53 departments in 7 faculties

NTNU Library

Museum of Natural History and Archaeology

20 000 registered students

2 850 degrees awarded

4

2 850 degrees awarded

314 doctoral degrees awarded

4 500 person-years

2 700 employed in education and research; 557 professors

Budget: EUR 550 million

560 000 m2 owned and rented premises

Degrees awarded in 2008

Lower degrees Higher degrees

Technology [not offered] 1 098Social Sciences 252 333Humanities 229 176Science 104 123Architecture [not offered] 90

EDUCATION

5

Architecture [not offered] 90Medicine [not offered] 117Psychology [not offered] 55Fine Art 13 7Performing Music 20 6Teacher Training Diploma 212 [not offered]

TOTAL 830 2 029

6

Education for international students

� No tuition fees

� Must document a minimum of NOK 85 000 (EUR 10 000) per year to cover living expenses

Categories of international students at NTNU:

� Exchange students

EDUCATION

7

� Exchange students

� Degree-seeking students (undergraduate and graduate)

� International master's programme students

� Visiting/non-degree students

� NUFU students

� PhD candidates

International Master program from 2008Silicon and Ferroalloy production

Ex Subject no.

Subject title Note Autumn F Ø S

Spring F Ø S

Credits Exam

1h

1h

1h

1h

1v

TMT4155

TMT4280

TMT4325

TMT4305

TMT4150

HETEROGEN EQUILIBRIA

EXTRACTIVE METALLURGY

REFIN/RECYCL METALS

ELECTROMETALLURGY

REFRACTORIES

4 2 6

4 2 6

4 1 7

3 1 8

4 2 6

7,5

7,5

7,5

7,5

7,5

Autumn

Autumn

Autumn

Autumn

Spring

8

1v

1v

1v

1v

TMT4150

TMT4230

TMT4165

MT8301

REFRACTORIES

METALLURGICAL ENGINEERING

MAT/ELECTROCH, PR.WORK

CARBON MAT TECHN

4 2 6

4 2 6

2 6 4

2 2 8

7,5

7,5

7,5

7,5

Spring

Spring

Spring

Spring

Total weighing

60,0

2h

2h

2h

TMT5500

TMT5505

TMT4300

PROC MET/ELECTR SP

PROC MET/ELECTR SC

LIGHT AND ELECTRON

MICROSCOPY

24

12

4 2 6

15,0

7,5

7,5

Autumn

Autumn

Total weighing

30,0

2v Master Thesis 30,0 Spring

Department of Materials Science and Engineering - DMSE

• Metallurgy• Electrochemistry• Inorganic chemistry

• Staff of 125 persons• 21 professors (+10 adjunct professors)• ~110 1st – 5th grade students

9

• ~110 1st – 5th grade students• ~ 10 exchange students • 60 Ph.D. students• 20 post doc.

Norway’s leading institution for teaching and research on materials

Materials one of NTNU:s priority areas

Areas of research - DMSE

Light metals (Al, Mg)ElectrolysisMelting, casting, weldingFormingMicrostructure & PropertiesAlloy developmentRefiningRecycling

Ceramic materialsHigh strengthFunctionalNanostructures

Energy TechnologyFuel cellsHydrogen storage

10

Recycling

Ferroalloys & siliconRaw materialsFerroalloy productionSilicon for solar cellsRefiningEnvironmental control

Hydrogen storage

OthersSteelCorrosionPowder metallurgyCatalysis….

11

SINTEF

SINTEF is one of Europe’s largest independent research organizations

Turnover NOK 1.7 billion, 1700 staff, 350 of these in Oslo

Established in 1950 as NTNU’s contract research organization

Contract research in technology, natural sciences,

R & D

12

Contract research in technology, natural sciences, medicine and social sciences

Cooperation with NTNU in terms of staff, equipment, laboratories and dissemination

13 Gemini Centres for joint NTNU/SINTEF R&D

Many NTNU staff are permanent SINTEF advisers

Many SINTEF staff are adjunct professors at NTNU

The SINTEF Group’s turnover in 2004,

by institute and research company

SINTEF Materials and Chemistry

SINTEF ICT

SINTEF Technology and Society

13

Gross operating income in NOK 1.7 billion

SINTEF Health Research

SINTEF Energy Research

SINTEF Fisheries and Aquaculture

SINTEF Petroleum Research

MARINTEK

SINTEF Holding

0 50 100 150 200 250 300 350 400 mill

The Norwegian Ferroalloy Producers Research

Association (FFF)

� Founded by the Norwegian ferroalloys industry to carry

out joint research on ferroalloy processes and products at

NTNU/SINTEF.

� Aims to maintain the Norwegian ferroalloys industry's

position at the forefront of developments in the production

14

position at the forefront of developments in the production

of ferroalloys and the supply of electro-metallurgical

technology and equipment.

� The aim is to pursue environmental improvement in the

ferroalloys industry.

� Support education of MSc’s and PhD’s for the ferroalloy

industry

The Norwegian Ferroalloy Producers Research

Association (FFF)

� Formed in 1989

� Members:Elkem ASAFESIL ASAFinnfjord Smelteverk AS

15

Finnfjord Smelteverk ASValeEramet Norway

� Annual Budget ~10 mill. NOK/year

� 4 – 6 PhD students on average

Mn-ores

Carbon materials

El-energy

16

Ferroalloys

1500-1600ºC

17

FFF - MANGANESE RESEARCH 1990-2010

� PROCESS MECHANISMS

�HC FeMn and SiMn Processes

�Pilot scale experiments

�Energy and mass balances

�Modeling of HC FeMn process

�Mineralogy of ores and agglomerates

� PREREDUCTION ZONE – Low temp. zone

�CO reactivity of manganese ores –kinetics and red. mechanisms

18

kinetics and red. mechanisms

�Thermal strength

�Thermal conductivity raw materials

�CO2 reactivity of carbon materials (incl. K)

�Use of agglomerates

�Fines generation of ore and carbon materials.

�Zn and K circulation in furnace

FFF - MANGANESE RESEARCH 1990-2010

� COKEBED ZONE – High temperature zone

�Melting relations

�Liquidus relations in HC FeMn and SiMn slags

�Wetting properties slag/carbon

�Slag kinetics

�C-reactivity

�Electrical resistivity of carbon

19

�Electrical resistivity of carbon materials

�Equilibrium data – experimental and databases

� Smelting reduction of HC FeMn

� Sludge recycling

� Biocarbon

� Emissions (incl. Diffuse emissions)

PhD Thesis - Manganese

� Ding W: Equilibrium relations in the production of manganese

alloys. 1993

� Skjervheim T A: Kinetics and mechanisms for transfer of

manganese and silicon from molten oxide to liquid manganese

metal. 1994

� Tangstad M: The high carbon ferromanganese process - Coke

bed relations. 1996

20

bed relations. 1996

� Wasbø S O: Ferromanganese furnace modelling using object-

oriented principles. 1996

� Berg K L: Gaseous reduction of manganese ores. 1998

� Hoel E G: Structures and phase relations in silicomanganese

alloys. 1998

PhD Thesis - Manganese

� J.Fenstad: Liquidus relations and thermochemistry within the

system Fe-Mn-C-O. 2000

� R.J.Ishak: Reaction kinetics for reduction of manganese ore

with carbon monoxide in presence of carbon. 2002

� J.Kozarowski: CO2 reactivity of carbon materials, 2006.

� J. Safarian: Slag-carbon reactivity, 2007.

21

� J. Safarian: Slag-carbon reactivity, 2007.

� P.A.Eidem: Electrical resistivity of carbon materials. 2008

� D.Slizovskiy: Sludge – from waste to product. 2011

� M.Ksiazek: Thermal conductivity of manganese ores. 2011

� T.Brynjulfsen: Agglomerates on furnace operation. 2013

Pilot experiments- Process mechanisms

150 mm

Silica sand

E

l

e

c

t

r

o

Charge

22

High Alumina

monolithic lining

Carbon paste lining

Tap hole

Bottom electrode

40 cm

50 cmo

d

e

Thin layer of

3mm size coke

Furnace in Operation

23

Charging Tapping

Dismantling the furnace

24

Shell and silversand removed Casting with Epoxy

Pilot experiments- Process mechanisms

25

Pilot experiments- reaction mechanisms

Tapped slag: 25%MnOTapped slag: 18.6%Al2O3 Tapped metal: 20.15%Si

26

1012

842

34128

31229

8

28

2726

302840

36364513

38253820

27,35

28

17

3022

13,1618,2221

17,2117,22217

18121415

15

016

27

Pilot scale experiments – Results

� Reaction mechanisms

� Geometry of zones

� Structure of cokebed

� Resistivity of cokebed

28

� Wettability of carbon materials

� Accumulation of SiO2 in high temperature zone

� Reduction behaviour Mn ore

� Reduction path – slag and metal composition

Al2O3+SiO2

60

70

80

90

1000

10

20

30

40

(A/S=0.5)

Basicity line = R

eduction path

Liquid area1500 oC

Basicity line = reduction path

29

MnO0 10 20 30 40 50 60 70 80 90 100

0

10

20

30

40

50

60

Σbas

50

60

70

80

90

100Basicity line = R

eduction path

Basicity line = Reduction path

MnO reduction by solid carbon

(MnO) + C = Mn + COThis reaction has been studied in graphite crucibles

Some important points:� 1- MnO reduction takes place in

two stages, a fast stage following

by a much slower stage

� 2- The transition from first fast

stage to the second stage occurs

Effect of temperature on weight loss

-2

-1

0

weight loss [g]

30

stage to the second stage occurs

when slag reaches its liquidus

composition and MnO activity

starts to decrease

� 3- The rate of reaction increases

by increasing temperature, the

reported activation energies are

in good agreement (about 370

KJ/mol).

-7

-6

-5

-4

-3

-2

0 2 4 6 8 10

time [h]

1450oC

1500oC

1550oC

In situ furnace – melting behaviour

31

Melting behavior at increasing temperature

32

Biocarbon

1997 - 2001: ”The use of biocarbon in Norwegian Ferroalloy Industry”22.3 mill NOK (2.5 mill USD)

2002 - 2004: ”Environmental friendly reduction processes”

33

2002 - 2004: ”Environmental friendly reduction processes”8.5 mill NOK (0.95 mill USD)

Long term goal

� Reduce emissions of CO2 from fossil carbon sources in Norwegian ferroalloy and silicon carbide production.

� Increase the share of biological carbon (biocarbon) with 20 % in the Norwegian ferroalloy production within 2010.

Conclusion: Manganese research and possible cooperation between Norway and South Africa

� Due to FFF, manganese research have been carried out

at NTNU/SINTEF since early 1990’s

� Possibilities of exchange between university and industry

� New international master program in Silicon and Ferroalloys from 2008 which is an individual part of the Nordic International Master

34

2008 which is an individual part of the Nordic International Master Program

� Industry cooperation within safety and environment

� Fundamental research between academic institutions

and industry

Manganese Process Research 1990-2005Steering committee with members from Elkem/ERAMET - Tinfos - NTNU

� 8 PhD Thesis

� 3 ongoing PhD projects

� 22 Master Thesis

� 7 Post.docs - 14 man-labour years:

� 27 International Publications and 31 SINTEF-Reports (1990-2002).

35

� 27 International Publications and 31 SINTEF-Reports (1990-2002).

PhD Thesis - Silicon & Electric Arcs

� Andresen B: Process model for carbothermic production of silicon metal.

1995

� Ingason H: Hollow electrodes in the production process for ferrosilicon. 1994

� Valderhaug Aa. M: Modelling and control of submerged-arc ferrosilicon

furnaces. 1992

� Hildal K: Steam explosions during granulation of Si-rich alloys. Effect of Al-

and Ca-additions. 2002

� Liping G: Transport phenomena in silicon vapour infiltrated argon arcs and

36

� Liping G: Transport phenomena in silicon vapour infiltrated argon arcs and

anode metal pools. 1993

� Holt N: A metallurgical reactor with three plasma torches. 1994

� Larsen H L: AC electric arc models. 1996

� Sævarsdóttir G A: High current AC arcs in silicon and ferrosilicon furnaces.

2002

PhD Thesis - various related

� Ringdalen E: Production of High Carbon Ferrochromium, Reaction

Mechanisms. 1999

� Røhmen E: Thermal behaviour of a sperical addition to molten metals. 1995

� Eijk C : The nature and role of titanium containing oxide inclusions in steels.

1999

� Onsøien M I: Microstructure evolution in ductile cast iron containing rare

37

� Onsøien M I: Microstructure evolution in ductile cast iron containing rare

earth metals. 1997

� Skaar I M: Monitoring the lining of a melting furnace. 2001

Results of laboratory measurements have made it possible to determine:

� Slag/metal distribution equilibria for Mn and Si� Carbon solubility in various ferroalloys� Phase- and melting- relations of relevant slag and metal systems � Kinetics of Mn-ore reduction including catalytic effect of circulating

alkalies regarding the Boudouard reaction.� Relation between degree of ore pre-reduction, and consumption of

38

� Relation between degree of ore pre-reduction, and consumption of carbon and electric energy.

� Effect and importance of slag basicity� To develop a ferroalloy (Mn-Fe-Si-Cr-C) database for thermodynamic

calculations in the FACT-WIN computer program.� Raw material properties

� Mn ores

� Reducing agents

Metal/Slag/Gas Equilibrium RelationsMetal/Slag/Gas Equilibrium Relations

SiO2

50

60

70

8020

30

40

50

1500

o1550

o

1600

o

ThermodynamicsThermodynamics

39

MnO0 10 20 30 40 50 60 70 80 90 100

0

10

20

30

40

50

CaO

60

70

80

90

100

Exp. 14500C

Exp. 15000C

Exp. 15500C

Exp. 16000C

Calculated

1400o

1450o

Metal/Slag/Gas Equilibrium RelationsMetal/Slag/Gas Equilibrium Relations

SiO2

50

60

70

8020

30

40

50

Cal., PCO=1atm

Cal., PCO=0.3atm

Exp. 1600oC, 1atm

Exp. 1550oC, 1atm

Exp. 1500oC, 1atm

Exp. 1450oC, 1atm

Exp. 1500oC, 0.3atm

CaO

/Al 2O

3=1.5

40

MnO0 10 20 30 40 50 60 70 80 90

10

20

30

40

50

C+A

50

60

70

80

90

CaO

/Al

Slag/Metal Equilibrium in FeMn ProductionSlag/Metal Equilibrium in FeMn Production

SiO

50

60

+C

aO

+M

gO

(w

t%)

40

50

Calculated

Exp., Si: <0.1%

Exp., Si: =0.1-0.5%

Exp., Si: 0.5-1.0%

Exp., Si: 1.0-2.0%

Exp., Si: 2.0-3.0%

41

MnO (wt%)

0 10 20 30 40 50 60 70 80 90 100

SiO

2 (wt%

)

0

10

20

30

40

Al 2O

3+C

aO

+M

gO

(w

t%)

60

70

80

90

100

CaO/Al2O

3=1.5, MgO/Al

2O

3=0.8

0.05%

0.1%

0.5%1.0%

2.0%3.0%

Slag/metalC-sat equilibrium

diagram

ThermodynamicsThermodynamics

42

Mn7Fe-Si-Csat alloys & MnO-SiO2-CaO-MgO-Al2O3 slags

18

20

22

A

β -SiC

Mn7Fe-Si-Csat

MnO-SiO2-CaO-MgO-Al

2O

3(CaO/MgO=2.5)

PTotal

= 1.0 atm

Si m

ass%

Si distribution between slag and metal in SiMn production

43

20 25 30 35 40 45 50 55 60

10

12

14

16

Graphite

84.02.01.0R=0.8

Si m

ass%

SiO2 mass%

ΣΣΣΣ Basic oxideR = ——————

Al2O3

Phase relatons: Liquidus content of MnO in FeMn slagversus slag basicity

MnO

(w

t%) 60

70

80

MnO-CaO-SiO2-Al2O3 slag

44

B=CaO/(Al2O

3+SiO

2)

0,0 0,2 0,4 0,6 0,8 1,0

MnO

(w

t%)

30

40

50

1450 oC

1500 oC

1550 oC

Al2O3/SiO2=0.5

A/S-ratio in range 0.25-0.5 of little importance

Replacement of CaO with MgO gives less MnO at liquidus

Smelt reduction Carbon

SlagEnergy

Metal

� Background� Research started with small

graphite crucibles

� Aim of Project� To utilise slag directly from the HC FeMn furnace

45

� To utilise slag directly from the HC FeMn furnace

� Produce SiMn directly

� Utilise the sensible heat of the slag

� Reduce handling and storage of HC FeMn slag

� Increase the productivity of SiMn furnace

� Less HC FeMn slag

� More Mn ore and quartz

� Possibly use less coke (different reductants)

Electrical conductivity in coke bedsPer Anders Eiden (2004-2008)

� Resistivity of beds of industrial carbon materials

� Parameters affecting the total resistance in coke beds

(experiments and modelling)

� (Geometry of cokebed – size and shape)

46

� (Geometry of cokebed – size and shape)

� Geometry of particles (incl. size)

� Packing (dependent on size and distribution)

� Type of carbon (coke, graphite, antracite,….)

� Inter-particle resistance

Electrical conductivity in coke bedsPer Anders Eidem (2004-2008)

47

Electrical conductivity in coke beds

48

Slag –Carbon reactivityJafar Safarian (2004-2007)

�MnO+C=Mn+CO(g)

�SiO2+2C=Si+2CO(g)M n-Fe-

Si-C sat

C O

bubbles

Slag

(SiO 2) + C O (g)

→ S iO(g) + C O 2(g)

C(gr.) + C O 2(g) → 2C O (g)SiO (g) + C →

Si + CO (g)

SiO(g)

transport

49

�Literature survey

�Wetting experiments

� Input to carbon characterisation method

G raphite

CO2 reactivityJakub Kaczorowski (2003-2006)

� Micro structure and other properties of

carbon materials

� Petrograpy (macerals and vitrinite

reflection)

Porosity and pore distribution

50

� Porosity and pore distribution

� Ash content and composition

� CO2 reactivity

� Carbon types, temperature, alkalies,

CO/CO2 ratio

� Industrial furnace sampling in prereduction

zone

CO2 reactivityJakub Kaczorowski (2003-2006)

� Coke from 3 single seem coals and 3 industrial cokes

51

CO2 reactivityJakub Kaczorowski (2003-2006)

Open pore distribution of Open pore distribution of

Polish and Australian single Polish and Australian single

seem cokesseem cokes

52

�� Thermochemical databases that have been Thermochemical databases that have been developed at SINTEF Materials Technology:developed at SINTEF Materials Technology:

�� AlAl--CaCa--CuCu--FeFe--MgMg--MnMn--SiSi--Zn system for the Zn system for the commercial Alcommercial Al--alloysalloys

�� MnMn--CrCr--FeFe--SiSi--CC--SS--P system for ferroalloysP system for ferroalloys

Thermotec -

53

�� MnMn--CrCr--FeFe--SiSi--CC--SS--P system for ferroalloysP system for ferroalloys

�� SiOSiO22--CaOCaO--AlAl22OO33--CrOCrO--CrCr22OO33--FeOFeO--FeFe22OO33--MgOMgO--MnO MnO oxide system for ferroalloy slagsoxide system for ferroalloy slags

�� Coupling thermochemical properties (databases) Coupling thermochemical properties (databases) with thermophysical properties (databases) : with thermophysical properties (databases) : density, viscosity, surface tension, ……density, viscosity, surface tension, ……

Phase Diagram for FeMn & SiMnPhase Diagram for FeMn & SiMn

6

7

8

9

10

univariant

isothermal

2300

2400o

M5C

2

C (

mass%

)

54

0 10 20 30 40

0

1

2

3

4

5

1050o

1100o

1150o

1200o

1250 o

1300 o

1400 o

1500 o

1600 o

1700 o

1800 o

1900 o

2000 o

2100 o

2200 o

2300o

M7C

3

Graphite

SiCββββ

M5Si

3

M3Siγγγγ-Mn

ββββ-Mn

εεεε-Mn

C (

mass%

)

Si (mass%)

Activity Activity -- Composition Relations of SiMn MeltsComposition Relations of SiMn Melts

0.5

0.6

0.7

0.8

0.9

1.0

Mn7Fe-Si-Csat

alloys

1400oC

1600oC

aC

Activity

55

0 5 10 15 20 25 30 35 40

0.0

0.1

0.2

0.3

0.4

0.5

aMn

aSi

Activity

Si mass%

The Max. Si% in MnSi by Carbothermic The Max. Si% in MnSi by Carbothermic

Reduction of MnO & SiOReduction of MnO & SiO22

30

40

Mn7Fe-Si-Csat

Alloys +

aSiO2

=0.2 Slags

PCO

= 0.33 atm

SiC+SiO

Mn-Si-Csat

Alloys +

SiO2-saturated Slags

Si m

ass%

1670o 1755o

56

1450 1500 1550 1600 1650 1700 1750 1800 18500

10

20

Mn7Fe-Si-Csat

Alloys +

SiO2-saturated Slags

SiC+SiO2

C+SiO2

Mn7Fe-Si-Csat

Alloys +

aSiO2

=0.2 Slags

Si m

ass%

Temperature oC

Equilibrium simulation results”reduction path” of raw materials

SiO2+Al

2O

3

60

70

80

90

1000

10

20

30

40

(Al2 O

(MgO

/CaO

=0.5

)

1500

o1550

o

5.0%10%

100-MnO-SiO2-Al2O3B = ——————————

SiO2+Al2O3

57

MnO0 10 20 30 40 50 60 70 80 90 100

0

10

20

30

40

50

60

CaO+MgO

50

60

70

80

90

100

2 O3 /S

iO2 =

0.5

)(MgO

/CaO

=0.5

)

1350o

1400o

1450o

0.01%

0.1%

1.0%

5.0%

Metal/slag/gas Equ.

Metal/slag Equ.

Reduction path

B = 0.46B = 0.9

SiO2+Al

2O

3

50

60

70

80

90

1000

10

20

30

40

50

60(A

l2 O

3 /SiO

2 = 0

.57)(CaO

/MgO

= 2

.8)

Spinel

Mullite

Galaxite

Anorthite

58

MnO0 10 20 30 40 50 60 70 80 90

10

20

30

40

CaO+MgO

60

70

80

90

= 0

.57)(CaO

/MgO

= 2

.8)

(Mn,Ca, Mg, Al)Oss

Liquidus surface of the MnO-SiO2-Al2O3-CaO-MgO (Al2O3/SiO2=0.57, CaO/MgO=2.8) system