Development of Japans Refining Technologies in the Past and Future 2004.6.2 By Kaoru Ichikawa Nippon Steel Corporation

Development of Japan’s Refining Technologies in the Past and Future

2004.6.2

By Kaoru Ichikawa

Nippon Steel Corporation

1. Introduction2. Behavior of Mn in the Steel-making

process3. History of Process Improvement and

Influence on Manganese

　　　　 (1) Top-and-Bottom blowing converter

　　　　　 (2) Hot metal pretreatment　　　　　 (3) LD-type hot metal pretreatment　　　　　 (4) MURC process

4. Steel product needs 　 (1) Automobile sheet steel 　 (2) Plate products

5. Future Development

Crude steel production

China

JapanJapanU.S.A.

Germany Korea

1950 60 70 80 82 84 86 88 90 92 94 96 98 00 02 03

200

180

160

140

120

100

80

60

40

20

0

Total

1000

800

600

400

200

0

220

Japanese peak120 million tons／1973

Cru

de s

teel

pro

duct

ion

(mill

on t

ons/

year

)

Tot

al p

rodu

ctio

n (m

illon

tons

/yea

r)

NIPPON STEEL CORPORATION

日本の鋼材消費量の推移日本の鋼材消費量の推移

1960 65 70 75 80 85 90 95 2000（年）

1,000

800

600

400

200

0

人口

当り

鋼材

見掛

け消

費量

（㎏／

人）

鋼材消費量は経済的な成長を示す尺度となる。先進工業社会では、年間500～600㎏／人程度の鋼材消費となる。

5

ChahgesChahges in the consumption of in the consumption of steel products in JAPANsteel products in JAPAN

The p

er

The p

er --ca

pit

a c

onsu

mption o

f st

eel

capit

a c

onsu

mption o

f st

eel

pro

duct

s (k

g p

er

pers

on)

pro

duct

s (k

g p

er

pers

on)

The average consumption in the advanced The average consumption in the advanced industrial nations is approx. 500 to 600 kg industrial nations is approx. 500 to 600 kg per person.per person.

Change ｓ in the consumption of steel products in JAPAN

Consumption of steel product in the world (2001)

1000

100

10100 1,000 10,000 100,000

GDP （US dollar per person）

Korea Japan 575kg

Russia 173kg

Thailand 121kg

China 132kg

India 27kg

GermanyU.S.A.

Average135kg

The p

erThe p

er-- c

apit

a c

onsu

mption o

f st

eel

capit

a c

onsu

mption o

f st

eel

pro

duct

s (k

g p

er p

erso

n)

pro

duct

s (k

g p

er p

erso

n)

Trend in steel demand in the world

Crude steel （2001）TotalTotal 846 846 million tonmillion tonAsia Asia 363 363 million tonmillion ton（（4242 ％）％）

10344 152

JapanJapan KoreaKorea ChinaChina

OthersOthers496496

The steel demand

900

700

500

300

100

362 422 449

AsiaAsia 2424％％

The world total increased The world total increased 1313％％

2001 2002 2003 2001 2002 2003 2001 2002 2003 2004

73 72 7238 44 44

174 211 232 255

（million t

ons）

Japan Korea China

Consumption of steel product Consumption of steel product （（million tonsmillion tons））

（（million tonsmillion tons））

Economic development in China

683 786974

11571338

1827

2334

3135

961 965823 690 727 718 602732

919 980 1044 10601210

12791351

1599

501 516 537 485 454 422 388 332

1997 98 99 2000 01 02 03 05

6

5

4

3

2

1

01995 96 97 98 99 2000 01 02

30

20

10

0

16

12

8

4

0

The outputs of automobilesThe outputs of automobiles The output of electric appliancesThe output of electric appliances

AutomobileAutomobile

BusBus・・TruckTruck

Fore

cast

Fore

cast

Air conditionersAir conditioners

RefrigeratorsRefrigerators

ChinaChinaJapanJapan

ChinaChina

JapanJapan48 50

110 112 127 146 164 216 420 600

5761 70

109 （million

）

（million

）

Crude steel production and the long-term trend in the world.

1,100

1,000

900

800

700

600

500

400

300

200Cru

de

stee

l p

rod

uct

ion（

mil

lion

ton

s /y

ear）

1960 70 80 90 2000 2010 2020

Crude steel productionCrude steel production

ForcastForcast made at the end made at the end of the 20th centuryof the 20th century

Forecast after China,a new Forecast after China,a new growing market, is taken growing market, is taken into accountinto account

Forecast for increased steel demand

2002

2010

2020

2030

2040

2050

Forecast for the world populationForecast for the world population Forecasts for the crude steel productionForecasts for the crude steel production

0 20 40 60 80 100 0 0.5 1 1.5 2

Asia Oceania

North America

South America

Europe Africa

(billion people) (billion tons)

0.9

Only

the p

opula

tion g

row

th is

taken

into

acc

ount

The economic growth of each region is also taken into account

1.35 1.95

Crude steel production

China

JapanJapanU.S.A.

Germany Korea

1950 60 70 80 82 84 86 88 90 92 94 96 98 00 02 03

200

180

160

140

120

100

80

60

40

20

0

Total

1000

800

600

400

200

0

220

Japanese peak120 million tons／1973

Cru

de s

teel

pro

duct

ion

(mill

on t

ons/

year

)

Tot

al p

rodu

ctio

n (m

illon

tons

/yea

r)

Progress in the division of refining function at Nippon steel.1)

1st phase 2nd phase 3rd phase Present(1957 1970)～ (1971 1980)～ (1981 2000)～

de S de S de Si de S de Si

de Si de P de Si de Sde S de P

Top Blow Top Blow de Pconverter converter

de Sde Si de Si de Si BOFde P de P de Pde C de C de C de C de C

de C de C de S de C de S Secondarydegassing degassing degassing degassing degassing refining

degassing Inclusion Inclusion processcontrol control

TPC- type → LD type－Ladle- typeTop-bottom

comvinedconverter

Top- bottomcomvined converter

Top- bottomcomvined converter

Separation of de-SHot metalPre-treatment

Consumption of Fe-Mn alloy in Japan & Mn-equivalent consumption in Japanese steel 2).

0

1

2

3

4

5

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

Mn

allo

y un

it (k

g/t)

HC-FeMnMC,LCSi-MnM.MnFe-Si

0

1

2

3

4

5

6

7

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

Mn

unit

(kg/

t)

TotalHC-FeMnMC,LC Fe-Mn, M.Mn, Si-Mn








Process Flux & oxygen content in Fe％[C] [Si] [P] [S] [Mn] Temp.

℃（）BF 1530

(dS) CaO、 4.5 0.4 0.1 0.02 0.3Hot Metal Mg or Na2CO3

Pretreatment (dP) CaO、 Fe- Ore O、 2 4 ｔｒ 0.02 0.005 0.2 1350

BOF CaO MgO、 Mn- Ore Fe- Ore O、 2 0.05 tr 0.02 0.005 0.15 1650

Secondary Refining Alloy

0.001 tr 0.005 0.001 0.15～Product 0.3～ 0.5～ 0.03～ 0.03～ 1.5 -

Reaction Condition

Basicity PO2 Temp.

Decarburization - High - Dephosphorization High High Low

Desulfurization High Low High

Reduction of MnO High Low High

An example of the steel making method & acceleration conditions for respective reactions.

　 C 　＋　 1/2O ２　＝　 CO

　 P 　＋　 5/4O ２　＋　 3/2CaO 　＝　 1/2Ca ３（ PO

４）２

　 S 　＋　 CaO 　＝　 CaS 　＋　 1/2O ２

　　 Mn 　＋　 1/2O ２　＝　 MnO

Example of calculation results of ferroalloys 3).

[C] [Si] [Mn]End point 0.05 0.00 0.15 [C] [Si] [Mn]Ladle aim 0.12 0.25 1.50 0.05 0.00 0.15 [C] [Si] [Mn] Upper limit 0.15 0.30 1.60 0.09 0.25 1.50 0.05 0.00 0.15 Lower limit 0.10 0.20 1.40 0.12 0.30 1.60 0.08 0.25 1.50

0.07 0.20 1.40 0.11 0.30 1.600.06 0.20 1.40

Alloy HCFeMnLCFeMn Si- Mn Caic. 1272 0 5237 kg/ heat HCFeMnLCFeMn Si- Mn Set 1272 0 5237 0 2385 3615 kg/ heat HCFeMnLCFeMn Si- Mn Yield 95 95 95 ％ 0 2385 3615 0 2385 3615 kg/ heat

95 95 95 ％ 0 2385 361595 95 95 ％

Chemical content （％）

C Si MnHCFeMn 6.85 0.00 74.50LCFeMn 0.86 0.00 81.00Si- Mn 2.20 14.50 60.70

Mn ＋ 1/2O 2 ＝ MnO

(%MnO) 1[%Mn] T

log = - 1.79 + 1.07× log (%T.Fe) + 3.980× - 0.048× log (%CaO/ %SiO2)

155 1 %MnO)（71 1000 [%Mn]

Mn yield =（％）1 + × × × Slag volume

× 100

Manganese yield

1. Introduction2. Behavior of Mn in the Steel-making process3. History of Process Improvement and






Process Bottom tuyere Bottom gas type Bottom gas flowconstruction rate(Nm3/ t/ min)

LD- OB Double- pipe tuyere O2,Ar,CO2,N2,LPG 0.10 to 0.60

LD- CB Small- diameter pipe CO2,N2,(O2) 0.01 to 0.10assembly plug

Fig. 　 Relation between turndown free oxygen and turndown carbon in top-blown, bottom-blown, and combined-blown converter 4).

Outline of combined-blown processes 4)

O2

CO2

N2

LPG

Changes in reaction using the top-and-

bottom blowing method 5).

O2

CO2

N2

LPG








82 84 86 88 90 92 94 96 98 00 02

Nipponn Kimitsu ★ ●Steel Yawata ★ ●

Oita ★ ▲ ●Nagoya ★ ●Muroran ★ ●

J FE Chiba ★Mizushima ★Keihin ▲ ●Fukuyama ▲ ●

Sumitomo Kashima ★ ●Wakayama ★ ● ●

Kobe Kakogawa ★ ★Kobe ●

★ TPC：▲ Ladle：● Converter：

Recent advances of hot metal pretreatment

in Japan 6).

Example of torpedo car hot metal pretreatment process (Kimitsu, Nippon

steel)4).

Example of ladle hot metal pretreatment process　 (Oita, Nippon

Steel) 4).

Changes in converter operating with introduction of hot metal pretreatment

and LD-OB process (Kimitsu) 4).

LD Hot metal pretreatmentprocess and LD- OB process(1981) (1989)

Monthly crude steel production 200,000 407,000capacity (t/ furnace/ month)

Hot metal pretreatment ratio (%) 0 69

Availability (%) 55.2 85.5

Tap- to- tap time (min) 34 28

Furnace life (heats) 1,795 5,340

Molten steel yield (%) 93.6 95.1

Total CaO consumption (kg/ t) 54.2 39.3

Ferromanganese consumption 6.4 4.2(kg/ t)

Effect of slag volume on dephosphorizing degree

and manganese yield (Oita) 4).

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120

Slag Volume (kg/ t)

Deph

osp

horiza

tion d

egr

ee (

%)

&M

anga

nese

yie

ld (

%)

Dephosphorizationdegree

Mn-yield65

256

85(P：120→ 18）

× 10- 3

％

26(P 24： → 18）

× 10- 3

％

Less slagblowingwith depho-sphorizedhot metalarea

ConventionalLD converterarea

Turn-down [Mn] by mass reduction of Manganese ore 7).

1.6 2.0 2.4 2.8

1.8

1.0

0.6

1.4

[C] 0.2＜％

Input [Mn] ( )％

[Mn]

()

at t

urn

-do

wn

％








Example of converter hot metal pretreatment process

(Nagoya ,Nippon Steel ) 4).

Comparison of hot metal dephosphorization process and

treatment conditions 8).

Free Exhaust Stirring Oxygen Oxygen Scrap Initialboad gas energy supplying gas ratio melting investment

treatment rate cost

Injection Process Small Simple Low Low Low Impossible Low

Top- and- bottom Large OG High High High Possible Highblowing converter System

Slag (T.Fe) De- Si Addition of Slag Slagbasicity content before fluorspar foaming utilization

de- P

Injection Process 4- 8 2- 5 Imperative Necessary Small Difficult

Top- and- bottom 1- 2 7- 18 Not Not Large Easyblowing converter Imperative Necessary

Process

Treatment condition

KR desulphurization and LD-type dephosphorization (Kimitsu) 9).

Manganese use in the LD-type process

For manganese use in the LD-type process,

manganese yield improvement

due to the decreased slag volume in the converter

can be obtained in the same way as using conventional technology.

However, a decrease in Mn during dephosphorization

cannot be avoided

due to increased %T.Fe and lowered basicity

during dephosphorization.

Evolution of chemical elements during desiliconization and dephosphorization at LD-

type dephosphorization 10).

The [Mn] value goes down.








The Outline of MURC process（Oita） 11).

Carging De[Si]/ [P] Deslagging De[C] Tap Solidificatin Con fir m a ti o n

Blow 1（） Blow （２）

Slag

Solidification

ConfirmationCharging De[Si]/ [P]

Nextch

Carging De[Si]/ [P]Blow 1（）

Charging

Speciality of MURC Process・Low Basicity, High (T.Fe), Low Temperature → High Efficiency De[P] (CaO/SiO2≦ ２），(T.Fe)≧ 8%，（～1350℃）

・High Gaseous Oxygen Ratio,Low HMR Operation・Slag Hot Recycle→ Reduction of Slag

Reductionof lime consumption by MURC process 11).

0

20

40

60

80

100

120

Conventional NoＭＵＲＣRecycle

ＭＵＲＣ

Tot

al C

aO C

onsu

mpt

ion

C

onve

ntio

nal B

low

（＝

１０

０％

）Hot Metal [Si]=0.42%　Low C Steel

Reduction of Slag Discharge by MURC process 11).

20

30

40

50

60

70

80

90

Conventional NoＭＵＲＣRecycle

ＭＵＲＣ

BO

F S

lag

(kg/

t)Hot Metal[Si]=0.42%Low C Steel 　（ Exclude Metal ,Water）

Manganese loss in the MURC process

Manganese loss in the MURC process increases

as a result of low basicity and high %T.Fe

during the dephosphorization process.

In addition, with dephosphorization and decarburization

being operated continuously,

the carry-over of phosphorus into the decarburization process increases,

requiring light dephosphorization treatment

in the decarburization process.

Since the smelting reduction of manganese ore

becomes difficult with increased manganese loss,

the turn-down [Mn] is consequently reduced

compared to that in the conventional pretreatment process.

Manganese alloy in the LD-type pretreatment & MURC process

・ In the LD-type pretreatment method, 　 priority is given to using scrap and reusing or reducing slag, 　 which is demanded by today’s society.

・ On the other hand, 　 the MURC process focuses on improving heat loss 　 and shortening the process time.

・ Neither technology emphasizes 　 reducing the volume of the Mn alloy used,　 So there is little or no reduction compared to the conventional pretreatment.








Steel product needs

• Market demands related to steel products are becoming increasingly strict.

• There has been continuous cost reduction in the refining process and cost increase due to improved and upgraded quality of steel products.

→We shall examine the changes in improved and upgraded steel products using automobile sheet steel and heavy plate products as example.








Trend of car weight and HSS ratio 12).

Application of TS 590 Mpa or higher steel to automobile 13).

Relation between tensile strength and elongation of HSS 14).

Conventional high strength sheet steel for automobiles used to be solid solution-hardened steel or precipitation-hardened steel with alloy added.

Currently, high strength steel products whose microstructure is reinforced for greater strength have been used.

(DP steel, TRIP steel)

Chemical compositions (mass%) and mechanical properties of the steels 15).

Yield Tensile Elon-Type of steel C Si Mn Ti strength strength gation

(Mpa) (Mpa) (%)

A Mild steel 0.05 0.01 0.24 - 241 384 43

B Solid solution 0.08 0.02 1.46 - 370 487 30hardened steel

C DP steel 0.05 0.89 1.25 - 432 618 27

D Precipitation 0.09 0.01 0.80 0.07 539 636 22hardened steel

E TRIP steel 0.15 1.48 0.99 - 510 644 37








Needs of the refining process and transition of the hot metal pretreatment

processEvolution of the hot metal pretreatment process Needs of the refining process in each period

1982～ Improvement in steel qualitySmall- quantity ・ - Low- P steel manufacturingLow- P steel manufacturing process ・

1982～ Energy savingMass production process・ - Reduction in T.CaO (auxiliary material)TPC type, Ladle type・ - Improvement in iron yield

- Reduction in Mn alloys

1999～ Rationalization→ Expansion of productivityMass production process・ Reduction in slag volume and reusing of slagLD pe・ｔｙ

Process in future Environmentally conscious product technology- Low environmental load - Minimized emission from the system: slag and dust - Reducing and recycling slag and dust - Reusing slag and dust- Reusing and recycling waste - Tires, automobiles and glassProcess featuring high degree of freedom of material (High efficiency dephosphorization and desulphurization, and an economical source of heat) - Adjustability for high- phosphorus and high- sulfur hot metal (high- phosphorus ore and high- sulfur fuel) - Utilization of low- grade steel scrap and dust

Conclusion

　 As for manganese use in the process in view of the above prospects,

　 we can assume that the smelting reduction of manganese ore

　 in the converter will not be actively employed in the future

　 since it decreases the scrap usage rate, increases slag generation

　 and results in a low yield level of manganese;

　 this is on the condition that the Fe-Mn price remains very economical.

　 As long as the main technological concern in the refining process

　 focuses on 　 improving the main reaction, namely dephosphorization,

　 the supply of manganese that has different reactive characteristics

　 will take the form that adds alloys.

　 The advantages of steel materials over other materials

　 include volume, price, strength, toughness and versatility. 　　 For the above sheet steel and plate products,

　 the need for higher grade, higher quality,

　 and meeting strict requirements 　 will grow in the steel market. 　

　 The base for developing higher grade, higher quality steel products

　 will be the addition of alloys to steel materials. 　

　 Fe-Mn alloys, especially low carbon alloys,

　 will be in much greater demand from now. 　

References

1 ） Kohtani,T. ： IISI 21 Annual Meeting & Conference, Report of Proceedings. 1987,p32 ） Ferroalloy Handbook, Japan Ferro alloy association.3 ） Nakamura,K. ： 7th International Ferroalloy Conference, (1995)4 ） Endoh,K. ： Nippon steel technical report No.61 (1994),p.1.5 ） Tada,M. and Masuda,S. ： Tetsu-to-Hagane, 65(1979), S675.6 ） Handbook of Iron and Steel 4th edition (2002), The Iron and steel Institute of Japan.7 ） Tabuchi,S et al ： Proceedings of the 6th International Iron and Steel Congress (1990),p57.8 ） Kitamura,S. et al ： 9th China-Japan Symp. on Sci. & Tech. of Iron and Steel Program, Nov.(2001).9 ） Tomita,K. et al ： 3rdEuropean Oxygen Steelmaking Conference, Nov.(2000),p59.10) Shima,H. et al ： 2nd European Oxygen Steelmaking Congress, Italy, Oct. (1997).11) Kumakura,M. ： 127th Seikou-bukai ,(2002), The iron and steel Institute of Japan.12) Kuriyama,Y. et al ： Journal of Society of Automotive Engineers of Japan, Vol.55,No.4 (2001), p.51.13) Yukihisa Komiya ： Kobe steel engineering reports Vol.52 No.3 (Dec.2002) P.2.14) Itoh,S. et al ： Bulletin of the iron and steel Institute of Japan, Vol.4, No.6 (1999), p.367.15) Uenishi.A, et al. ： Nippon steel technical report No.81 (2000),p.18.16) Amano,K. ： Bulletin of the iron and steel Institute of Japan, Vol.8(2003)No.10,p.2117) Advanced Technology of Plate Production in Japan, The iron and steel Institute of Japan ,(1984) p116.

Documents

Development of Japans Refining Technologies in the Past and Future 2004.6.2 By Kaoru Ichikawa Nippon Steel Corporation