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August 30, 2011

Akio Hayashi,

Fellow

JFE Steel Corporation

Steel Research Laboratory

Development of CO2 Fixation Technology

by Seaweed Bed Formation

Using Steelmaking Slag

– Coastal Environment Restoration

Using Recycled Materials –

1

Contents

1. Absorption of CO2 by Coastal Ecosystem:

Blue Carbon

2. Development of Coastal Environment Restoration

Technology Using Steelmaking Slag

3. Experiment of Coastal Environmental Restoration

& CO2 Fixation Demonstration in Kawasaki Port

2

1. Absorption of CO2

by Coastal Ecosystem

: Blue Carbon

3

Coastal ecosystems such as seaweed beds, etc. are

an important CO2 sink. (870 million ~ 1.65 billion

tons-CO2 /Yr.)

Due to development, coastal ecosystems are

decreasing.

• Decrease of approximately 30% from the 1940’s to

present.

• Stopping this decrease is one effective

countermeasure

• against global warming.

Under the name of Blue Carbon (Blue Carbon

Dioxide Sink), all countries are called on to make

efforts to protect coastal ecosystems.

4

1) Use of recycled material containing iron

(by-product of Steelmaking)

2) Restoration of coastal environments

(seaweed bed formation, etc.)

3) CO2 absorption by seaweed

2. Development of Coastal

Environment Restoration

Technology Using

Steelmaking Slag

5

What is Steelmaking Slag?

Blast furnace Converter

Blast Furnace Slag

Generated in the process of

producing pig iron by pouring

iron ore (sintered ore) & coke

into the blast furnace.

Steelmaking Slag

Generated in the process of

producing steel from pig iron

in the converter.

Ironmaking Process Steelmaking Process

6

Properties of Steelmaking Slag

*1: solidification at the contact with water.

Granulated blast

furnace slag

Air-cooled blast

furnace slagSteelmaking slag

Appearance

Particle density g/cm3 2.6～2.8 2.6～2.8 3.2～3.6

Unit weight kg/l 1.3 1.5～1.7 2.1～2.4

Chemical

properties

Hydraulic property *1Large Medium to small Medium

(solidified dredged soil )

pH of leachate

(leached water)

pH=10 (approx.) pH=10 - 11 pH=12 (approx.)

Others P, S adsorption & swelling

SiO2 CaO Al2O3 T-Fe MgO TiO2 MnO S

Blast furnace slag 33.8 42.0 14.4 0.3 6.7 1.0 0.3 0.84

Steelmaking slag 13.8 44.3 1.5 17.5 6.4 1.5 5.3 0.07

Andesite (reference) 59.6 5.8 17.3 3.1 2.8 - 0.2 -

1cm 1cm1cm

Chemical Composition of Slags (Source: Brochure of Nippon Slag Association)

7

1. Composition

2. Availability in Japan

10 million tons/year

3. Accessibility Generated at oceanfront steel works:

advantageous for marine transportation

Overcomes Typical

Problems

1. Difficulty to obtain sea

sand

Main components are

friendly to marine environment

CaO

SiO2

Fe

2. Difficulty to obtain

materials on land

3. Difficulty to use

imported sand

Steelmaking Slag

Advantages of Using Steelmaking Slag

8

Recent Developments of Technology for

Effective Utilization of Steelmaking Slag

in Coastal Areas by Industry-Academia-

Government Cooperation

Source: Japan Iron and Steel Federation

Government

AcademiaIndustry

9

Steelmaking

slag

[high f-Cao]

Reduction of pH

Immersion of mixture into seawater

Adsorption of phosphate/sulfide

Dredged soil

［qu=0kN/m2

］

Mix

Increase in Strength

pH=8.7

Ca in slag

Si and water indredged soil C-S-H

No mixture (slag only)

pH=11.8

Result: Improved Technology for Mixing

Steelmaking Slag & Dredged Soil

Expansion of applications by mixing dredged soil & converter steel slag

Source: Japan Iron and Steel Federation

Shaking for 30min

(amplitude 5cm, 200rpm)

PO

4-P

Slag mix Sand mix Dredged soil only

Result of Laboratory Experiment

White turbidity

Mixing ratio 10%

Mixing ratio 30%

Mixing ratio 50%

qu (

kN

/m2)

Curing time

10

Artificial seaweed bed & shallow bottom

Steelmaking slag + Dredged soil

Soil improvement

Eel grass (Zostera

marina) bed

Restoration of Coastal Environment

Seaweed settlement baseSubmerged dike

Form seaweed beds, shallow bottoms & tidal flats

which serve as a “cradle” for fish and shellfish.

Brown algae

(Ecklonia cava)

grown thick on

Seaweed settlement

block

11

CO2 Absorption by Seaweed

CO2 absorption by seaweed

55 ton-CO2/ha/yr.

Decrease of seaweed beds are in Japan

in the past 30 years

△80,000ha: 200,000ha→120,000ha

After restoration

+ 80,000ha : 120,000ha→200,000ha

5 million tons of CO2 /yr. absorption

is expected.

12

3. Experiment of Coastal

Environment Restoration &

CO2 Fixation Demonstration

in Kawasaki Port

13

Demonstrate the effect of using mixture of

Steelmaking slag & Dredged soil on seaweed

growth

To contribute to a low carbon society

• Form artificial & viable seaweed beds using a

mixture which supplies Fe ions.

• Quantify CO2 Capture & Storage (CCS)

• Assess the amount of biomass fuel

Purpose of the Experiment

Targets of the Experiment

14

Organizations

Cooperating Entities

Cooperation

Ministry of Economy, Trade and Industry (METI)

Grants

Organizations Involved

○ Local governments, etc.

∙ Kawasaki City

∙ Kagawa Prefecture

∙ Ministry of Land, Infrastructure,

Transport and Tourism (MLIT),

Kanto Regional Development

Bureau, Port and Airport

Department

○ Local companies

∙ Nippon Steel Corporation

○ NPOs

∙ Act Kawasaki

∙ Liaison Center for Creation of

Industry & Environment

∙ Kawasaki Marine History

Preservation Society

○ Local companies

∙ IDEA Consultants Inc.

∙ JFE Steel Corporation

∙ JFE Mineral Co., Ltd.

∙ Tokyo Gas Co., Ltd.

○ Universities

∙ University of Tokyo

∙ Institute of Industrial Science, University of

Tokyo

∙ Tokyo University of Agriculture

∙ Yokohama College of Pharmacy

○ Research institutes

∙ National Institute for Materials Science (NIMS)

∙ Port and Airport Research Institute (PARI)

∙ Fisheries Research Agency (FRA)

∙ National Institute of Advanced Industrial

Science and Technology (AIST)

∙ National Institute for Environmental Studies

(NIES)

∙ Kagawa Prefectural Fisheries Experimental

Station

15

Conversion of biomass to fuel

Increase in fish

& shellfish

Supply of Fe2+

& other minerals

Environmental improvement by suppressing leaching of H2S

Recovery of dissolved oxygen (DO)

Construction of seaweed beds

using mixture of Slag & Dredged soil

Seaweeds(grow 2-3 times faster than

on natural materials)

CO2

Image of CO2 Capture & Storage (CCS) by

Seaweed in Formation of Seaweed Beds

Artificial stones

made of Slag

16

SYMBOLS

Land for other uses

Land for port related uses

Land for traffic functions

Greenbelt

Land for pier use

Location of Seaweed Bed Formation

& Demonstration Tests

①

Kawasaki Port Tunnel at Higashi-Ohgishima entrance

17

Test Cases in Demonstration Tests

Controlled area

Mound E

Mound F

Large container 2m x 2m x 1m

Slag area

Mound A

11m x 5m x 1m

Slag area

Mound B

Mound C

Mound D

Large container

2m x 2m x 1m

マウンドA

マウンドB マウンドE

マウンドC マウンドF

マウンドD

凡例

：スラグ混合材

： 〃

： 〃

：天然砂

：フロンティアロック

：天然石

：ワカメ

：コンブ

：アカモク

Mound A

Mound D

Mound C

Mound B Mound E

Mound F

Symbols

: Slag mixture

: Slag mixture

: Slag mixture

: Natural sand

: Frontier Rock®

: Natural stone

: Wakame seaweed

: Kelp

: Brown seaweed

18

Flow of Demonstration Tests

Demonstrate the viability of CO2 fixation using

the mixture of Steelmaking slag & Dredged soil

Supply of steel slag from steel works

Construction of seaweed beds in Port of Kawasaki

Supply of dredged soil from Port of Kawasaki

Preparation of mixture

Seaweed planting andgrowth test

Calculation of CO2 reduction

Site Monitoring

Monitored items:

Stability of seaweed beds

Growth of seaweeds

Fe concentration in seawater

19

Timeline of Demonstration Tests

August 2009 Preparing mixture of Steelmaking slag &

Dredged soil

Application of mixed material &

construction of mounds (Mounds A – F)

November 2009 Monitoring survey

Planting of juvenile seaweed

(Sargassum horneri)

Planting of juvenile seaweed (wakame, kelp)

December 2009 Monitoring study (1 month after planting)

January 2010 Monitoring study (2 months after planting)

March 2010 Monitoring study (4 months after planting)

20

Table 1

Moisture ratio w % 111.8

Wet density t g/cm3 1.408

Dry density g/cm3 0.67

Soil particle density g/cm3 2.64

Liquid limit wL % 109.7

Plastic limit wP % 39

Plasticity index IP % 70.7

Liquidity index (w-wP)/(wL-wP) - 1.07

% 91.6

% 1.2

% 8.5

Proportion of particles under 75mm

Total organic carbon

Ignition loss

d

s

Moisture ratio w % 111.8

Wet density t g/cm3 1.408

Dry density g/cm3 0.67

Soil particle density g/cm3 2.64

Liquid limit wL % 109.7

Plastic limit wP % 39

Plasticity index IP % 70.7

Liquidity index (w-wP)/(wL-wP) - 1.07

% 91.6

% 1.2

% 8.5

Proportion of particles under 75mm

Total organic carbon

Ignition loss

d

s

Characteristics of the dredged soil

sampled in Ukishima

21

Chemical composition of

Steelmaking slag

SiO2 Al2O3 CaO MgO MnO P2O5 Al2O3 Total-Fe Metal-Fe FeO

10.7 3.70 38.1 6.69 2.43 2.24 3.70 22.6 1.94 9.71

SiO2 Al2O3 CaO MgO MnO P2O5 Al2O3 Total-Fe Metal-Fe FeO

10.7 3.70 38.1 6.69 2.43 2.24 3.70 22.6 1.94 9.71

22

Preparing Mixture of Steelmaking Slag

& Dredged Soil

Steelmaking slag & Dredged soil

are mixed by a backhoe on a soil hopper barge.

Composition: Dredged soil 70%, steel slag 30%

Curing time: 2 days

23

Solidified mixture after curing

Compressive strength: 110 kN/m2

Preparing Mixture of Steelmaking Slag

& Dredged Soil

24

Results of Water Quality Monitoring Survey

Mound A

Mound B - D

Mound E, F

Study

(Slag &

Dredged soil

mixture) Control

(Natural sand)

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Location of mounds

25

ｐH

7.7

7.8

7.9

8.0

8.1

8.2

8.3

8.4

8.5

Jul Aug Sep Nov Dec Jan Feb Mar

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Monthly changes of water Acidity of seawater

26

DO (mg/L)

0

2

4

6

8

10

Jul Aug Sep Nov Dec Jan Feb Mar

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Monthly changes of dissolved Oxygen in seawater

27

T-N(m g/L)

0.0

0.5

1.0

1.5

2.0

Jul Aug Sep Nov Dec Jan Feb Mar

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Content of total Nitrogen in seawater

28

T-P(m g/L)

0.00

0.05

0.10

0.15

0.20

Jul Aug Sep Nov Dec Jan Feb Mar

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Content of total Phosphorus in seawater

29

M g(m g/L)

0

200

400

600

800

1000

1200

Jul Aug Sep Nov Dec Jan Feb Mar

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Content of Magnesium ion in seawater

30

Fe(m g/L)

0.000

0.005

0.010

0.015

0.020

0.025

0.030

Jul Aug Sep Nov Dec Jan Feb Mar

Mound A

Mound B

Mound C

Mound D

Mound E

Mound F

Content of Ferrous ion in seawater

31

Element Mound A Bottom

sediment standards

Hg or Hg compound <0.0005 0.005

Cd or Cd compound <0.01 0.1

Pb or Pb compound <0.01 0.1

Cr(Ⅵ) or

Cr(Ⅵ) compound <0.05 0.5

Cu or Cu compound <0.1 3

Zn or Zn compound <0.1 2

Be or Be compound <0.1 2.5

Cr or Cr compound <0.1 2

Ni or Ni compound <0.1 1.2

V or V compound <0.1 1.5

Concentration of various hazardous heavy metals

dissolved from Mound A after 180 days (mg/L)

32

Immediately after transplanting

After 120 days

Juvenile Seaweed (Wakame

=Undaria pinnatifida) Growth Test

3 cm

Max 200 cm

33

Average (A~C) 29.3 g Average (E, F) 25.9 g

Dry

wei

ght

(g)

Len

gth

of

Sea

wee

d (

m)

Average (A~C) 29.3 g Average (E, F) 25.9 g

Dry

wei

ght

(g)

Len

gth

of

Sea

wee

d (

m)

Length (a) & Dry weight (b) of Wakame

in March from various mounds

29.3 g / 25.9 g = 1.13

Control areaStudy area

Dry

we

igh

t(g

) L

en

gth

(cm

)

34

Immediately after transplanting

After 120 days

Juvenile Seaweed (Akamoku = Sargassum homeri)

Growth Test

10 ~ 15 cm

Max 600 cm

35

0

200

400

600

800

A

Artificial

stone

A

Natural

stone

B

Natural

stone

C

Artificial

stone

C

Artificial

stone

D

Artificial

stone

E

Artificial

stone

F

Natural

stone

Study area(slag mixture) Controlled area

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Len

gth

of

indiv

idual

(m

) D

ryw

eig

ht

(g)

was

hed

aw

ay

was

hed

aw

ay

was

hed

aw

ay

was

hed

aw

ay

(a)

(b)Average (B~C)

67.0 g

Average (E, F)

31.8 g

0

200

400

600

800

A

Artificial

stone

A

Natural

stone

B

Natural

stone

C

Artificial

stone

C

Artificial

stone

D

Artificial

stone

E

Artificial

stone

F

Natural

stone

Study area(slag mixture) Controlled area

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Len

gth

of

indiv

idual

(m

) D

ryw

eig

ht

(g)

was

hed

aw

ay

was

hed

aw

ay

was

hed

aw

ay

was

hed

aw

ay

(a)

(b)Average (B~C)

67.0 g

Average (E, F)

31.8 g

Length (a) & Dry weight (b) of Akamoku

(Sargassum homeri) in March from various

mounds 67.0 g / 31.8 g = 2.11D

ry w

eig

ht(

g)

L

en

gth

(cm

)

36

Presence of Organisms after Construction

Inhibition of settlement by organisms was not observed in

the areas of Slag mixture seaweed beds compared with

those constructed of natural sand.

37

Conclusion

The mixture of Steelmaking slag & Dredged soil

can be transformed into viable seaweed beds

1. The mixture keeps the necessary strength of

solidification.

2. The mixture supplies Fe ions which enhance growth

of seaweed.

3. Seaweeds (Akamoku = Sargassum homeri) on Slag

mixture seaweed beds grow 2 times bigger than those

on natural sand.

4. Inhibition of settlement by organisms was not

observed in the areas of Slag mixture seaweed beds

38

END

Thank you very much for your kind attention.