Slag Itroduction

The Slag Sector in the Steel Industry

Table of Contents

1. Introduction......................................................................................................................... 1

2. What is Slag? ...................................................................................................................... 3

3. The History of Ferrous Slag Recycling ............................................................... 5

3.1 The History of Recycling ....................................................................................................... 5

3.2 Volumes Consumed ............................................................................................................. 13

4. Utility and Usage of Ferrous Slag Products .................................................. 15

4.1 Blast-Furnace Slag Products .............................................................................................. 15

4.2 Steel Slag Products.............................................................................................................. 17

4.3 Procurements Qualified Under the Law on Promoting Green Purchasing .................... 18

4.4 Recycling Technology Policy for Port and Airport Infrastructure: Ferrous Slag Products

at MLIT Ports and Harbors Bureau......................................................................................... 18

4.5 Technology Development for Use in Marine Environment Remediation........................ 18

4.6 Law for Promotion of Effective Utilities of Resources ...................................................... 19

4.7 Instances of Use in Major Construction Projects .............................................................. 19

4.8 Chemical Composition of Ferrous Slag Products and Their Conformance to

Environmental Standards......................................................................................................... 22

5. Control of Ferrous Slag from Generation to Customer Use................. 27

5.1 Production Control of Ferrous Slag Product ..................................................................... 27

5.2 Control of Ferrous Slag Product from Shipment to Customer......................................... 31

6. Summary............................................................................................................................. 32

Annexes: Chronology of Ferrous Slag Activities

July 2006 The Japan Iron and Steel Federation

Nippon Slag Association

1

1. Introduction

Iron and steel are basic materials that underpin modern civilization, and due to many years

of research the slag that is generated as a by-product in iron and steel production is now in

use as a material in its own right in various sectors. Slag enjoys stable quality and properties

that are difficult to obtain from natural materials and in the 21st century is gaining

increasing attention as an environmentally friendly material from the perspectives of

resource saving, energy conservation and CO2 reduction.

Blast Furnace Slag and Steel Slag

• Iron and steel slag is broadly divided into blast furnace slag and steel slag (basic oxygen

furnace slag and electric arc furnace slag).

• Blast furnace slag:

Constituents other than iron in the iron ore melted in a blast furnace become slag together

with the ash content in the limestone and coke by-product and are separated from the pig

iron and recovered. This blast furnace slag has constituents similar to those of natural

rocks, and around 290 kg is generated per ton of pig iron.

• Steel slag:

The steelmaking process consists of refining pig iron, scrap and other material to produce

steel, either in a basic oxygen furnace or an electric arc furnace. Steel slag (basic oxygen

furnace slag and electric arc furnace slag) is that generated in this steelmaking process, in

amounts of 110 to 120 kg per ton of crude steel.

Stable Quality

The primary constituents of slag are lime (CaO) and silica (SiO2). These constituents are also

contained in earth crust in general or in ordinary rocks and minerals, and their chemical

composition is similar to that of regular sedimentary rock and Portland cement. CaO, the

primary constituent of slag, is soluble in water and exhibits an alkalinity like that of cement

or concrete. And as it is removed at high temperatures of 1,200°C and greater, it contains no

organic matter whatsoever.

Resource Saving, Energy Conservation and CO2 Reduction

The characteristics of the slag that are generated as by-products in steel production are now

exploited for use in various sectors. From the perspectives of resource saving, energy

conservation and CO2 reduction, these slag are also highly-regarded materials to reduce the

load placed on the environment.

2

Resource saving Energy conservation CO2 reduction

Saving of natural resources (limestone, crushed stone, sand, etc.)

ca.40% less consumption with Portland blast-furnace slag cement than with ordinary cement (fuel, electric power, etc.)

ca.40% less with Portland blast- furnace slag cement than with ordinary cement

Assuming Portland blast-furnace slag cement with 45% blast furnace slag content.

Throughout the long history of the iron and steel industries, ways have been sought to make

effective use of these slag, but their traditional use as landfill material has been nearing its

limit with the massive expansion of the steel industry since the mid-1970’s. The steel

companies have since taken on as among their important management challenges the

development of technology, the maintenance of production facilities and certification for

ferrous slag products in the market in order to expand the applications of these slag, and the

Japan Iron and Steel Federation (JISF) and Nippon Slag Association (NSA) have promoted the

institution and widespread adoption of Japan Industrial Standards (JIS). As a result, 99% of

slag is now useful material, employed by such national agencies as the Ministry of Land,

Infrastructure and Transport and by local governments and other users, and it has gained

both high acclaim and certification.

With the adoption of the Law for Promotion of Effective Utilities of Resources, expectations

have risen for containment of the generation of slag as a by-product of the steel industry and

for the effective utilization of slag as a recyclable resource. The Law on Promoting Green

Purchasing further instituted an extensive list of “qualified procurements” that national and

local governments actively seek to include in their procurements.

This paper summarizes the history of iron and steel slag recycling, its utility and usage, and

the state of its control from generation through sale in order to promote understanding of how

it has been handled and efforts made to date in the slag sector of the steel industry.

3

2. What is Slag? Slag, as shown in Figure 1, is broadly divided into slag derived from metal production

processes and slag derived from waste heat-treatment and melting. Slag derived from metal

production processes further consists of ferrous slag and non-ferrous slag. This paper deals

with the ferrous slag derived from Iron and steel production processes (those within the

dotted line in Figure 1).

Figure 1 – Types of slag

Figure 2 describes the flow of production of ferrous slag, which may be broadly divided into

blast furnace slag and steel slag. Blast furnace slag may be either granulated slag, a glass

form that has been quenched, or air-cooled slag, which has been cooled in the atmosphere. In

FY 2004 granulated slag amounted to 78% of Japanese slag nationally.

Granulated slag is primarily used as a material in cement and recently is also widely used as

fine aggregate for concrete and in civil engineering works. Air-cooled slag is primarily used as

a road-building material.

Most steel slag is used in such civil engineering works as weak ground improvement. Mixed

with air-cooled slag, it is also used in road building as composite roadbed material.

Slag Slag from metal production processes

Ferrous slag Blast furnace slag

Steel slag

Non-ferrous slag

Granulated BF slag

Air-cooled BF slag

Basic oxygen furnace slag

Electric arc furnace slag

Ferronickel slag

Copper slag

Slag from waste heat-treatment & melting Fused waste slag, sewage sludge slag, etc.

4

Mill oxide

Iron ore

Sub-raw

materials

Quicklime

Scrap

Quicklime Sub-raw

materials Ferroalloy

-l

Figure 2 – Flow of steel slag production (Source: Nippon Slag Association)

Iron ore

Coke Sub-raw

materials Limestone

Quicklime Sub-raw

materials Ferroalloy

Blast furnace slag

Hot air

Blast furnace

Air-cooled slag (Air-coooled)

Slag (290 kg/ton)

Cooling yard

Pig iron

Crusher Screen

Fine aggregate for concrete Cement material

Ageing à Roadbed material

Granulated slag (water-cooled)

Crusher Screen

Basic oxygen furnace

Granulater Aggregate for asphalt mixtures Fine aggregate for concrete

Blast-furnace cement and cement material Earthworkand ground improvement material

Steel slag

BOF slag (incl. Preliminary treatment slag)

Cooling yard

Ageing à Roadbed material ground improvement material

Crusher Screen Slag (110 kg/ton)

Cement material and Earthwork material

Tapping

Electric arc furnace slag

Electric furnace

Electrode

Crusher

Ladle Ladle-refining furnace

Air-cooled slag (Air-coooled)

Cooling yard

Crusher Screen

Slag (120 kg/ton)

Crusher Screen

Aggregate for asphalt mixtures aggregate for concrete

Cooling yard

Roadbed material and ground improvement material

Ageing

Earthwork material

Cement material and ground improvement material

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3. The History of Ferrous Slag Recycling 3.1 The History of Recycling

(1) Background

• The history of recycling ferrous slag is a long one. Production of Portland blast-furnace

slag cement began in 1910, and the Japanese national standard for Portland blast-furnace

slag cement (JES 29) was formulated in 1926.

1960-73: Rapid Economic Growth

• Extensive use in reclamation and land formation at a succession of steelworks projects at

waterfront.

• Use as roadbed material begins in late-1960’s.

Since the Oil Shock of 1973

• Steelworks construction dropped off, but attention focused on the importance of resource

saving and energy conservation.

• Requirements of resource saving and energy conservation drive slag recycling

dramatically with an active push for the development of application technologies and

gaining public awareness.

(2) Promotional Frameworks

1) Industry The Japan Iron and Steel Federation Nippon Slag Association

1966 Six sales companies form Slag Products Study Group in Osaka

1968 Renamed the Japan Slag Group 1972 Blast-Furnace Slag JIS Standardization

Committee formed 1972 Road-building Slag JIS Proposal Drafting

Committee established 1975 Japan Slag Group moves to Tokyo 1976 Slag Recycling Committee formed 1976 Renamed the Japan Slag Society 1978 Japan Slag Society progressively

dissolved, Nippon Slag Association formed with steelmakers

1984 Regular work of Slag Recycling Committee transferred to Nippon Slag Association

* For certification pursued by Nippon Slag Association, see the annexed Chronology of Ferrous

Slag Activities.

2) Steelmakers

From the mid-1970’s and into the 1980’s the steelmakers too recognized that recycling ferrous

slag was an important management challenge and formed specialist slag organizations to

promote public awareness campaigns for the development of slag product technologies and

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the formation of markets for them.

One example is that of Nippon Steel Corporation:

(1) Slag Planning Group established in the Planning Division (1971)

• Promotion of certification to expand and stabilize sales of blast furnace slag

• Development of application technologies for and commercialization of product of

basic oxygen furnace slag

(2) Slag Recycling Promotion Group established (1976), renamed Slag Recycling

Promotion Office (1977)

Key Challenges Engaged

• Organizational

Leave off from “selling slag as a leftover” and position slag as a “new line of

business”. Organize as follows to position Nippon Steel as the guarantor of a stable

supply in terms of both quality and quantity.

-- Switch from system of selling raw ore to pre-existing slag processing and selling

operations to system of processing and sales at Nippon Steel’s own responsibility.

-- Organization for slag processing and sales established at each steelworks.

• Promotion of technology development

• Promotion of certification of slag product

(3) Slag Recycling Promotion Group renamed Slag Business Development Division (1978)

(3) Patent Applications

Thus, the industry and the companies that make it up have constructed a framework and

worked to develop application technologies and secure certification for ferrous slag product.

Figure 3 shows the number of published patent applications annually in the field of ferrous

slag over a recent 20-year period. Fruitful work continues across the industry to develop new

application technologies and improve production technologies even now that 99% of all

ferrous slag generated is recycled.

number

Figure 3 – Published patent applications in the field of ferrous slag

Year of applications

7

(4) Capital Investment

Steelmakers have installed the following production equipment to produce ferrous slag

product.

1) Granulated Blast-Furnace Slag Product Production Equipment

• In granulation equipment such as that shown in Figure 4, granulated blast-furnace

slag is produced by injecting high-pressure water from a granulator at a point

downstream of the molten slag and then quenching and granulating the slag.

• With the increased consumption of Portland blast-furnace slag cement as a means of

resource saving and energy conservation after the Second Oil Shock of 1979,

granulated slag production facilities were upgraded in order to increase the production

of granulated blast-furnace slag that is a basic input for such cements. 78% of

blast-furnace slag currently goes to such production.

Figure 4 – Granulated slag production facility

Granulated slag

Ratio(％)

Figure 5 – Transition of granulated slag ratio

Discharge conveyor Stirring tank

Granulator

Blast furnace

Dewatering equipment ( rotating-drum filter)

Water pump

Slag tank

Shipment Water tank

8

2) Air-Cooled Blast-Furnace Slag Product Production Equipment

Molten slag produced in blast furnace is discharged to a cooling yard and naturally cooled

standing with moderate sprinkling. The crystallized rocky slag then undergoes crushing,

sieving and removal of magnetic matter to produce roadbed material or coarse aggregate for

concrete.

3) Steel Slag Product Production Equipment

Molten slag generated in basic oxygen furnaces or electric arc furnaces is discharged to a

cooling yard or slag ladle and naturally cooled standing with moderate sprinkling. The

crystallized rocky slag then undergoes crushing, sieving and removal of magnetic matter to

achieve granularity appropriate to its intended application. Because steel slag contains free

lime and has the property of expanding in reaction with water, it is shipped after its

expansion is stabilized by, depending on the application, “natural ageing” in which it is cured

for long periods outdoors in natural rainfall and other weather or “steam ageing” which

employs high-temperature vapor.

(5) Certification

The status of significant certification is as follows.

1) Japanese Industrial Standards (JIS)

Those ferrous slag products defined in Japanese Industrial Standards (JIS) are as follows.

These account for 64% of all slag products.

JIS R 5210 Portland cement (instituted 1950, revised 2003)

(1979 revision permitted 5% or lower admixtures of blast-furnace slag.)

JIS R 5211 Portland blast-furnace slag cement (instituted 1950, revised 2003)

JIS A 6206 Ground granulated blast-furnace slag for use in concrete (instituted 1995,

revised 1997)

JIS A 5011-1 Slag aggregate for concrete – Part 1: Blast-furnace slag aggregate (instituted

1977, revised 2003)

JIS A 5011-4 Slag aggregate for concrete – Part 4: Electric arc furnace oxidizing slag

aggregate (instituted 2003)

JIS A 5308 Ready-mixed concrete (instituted 1953, revised 2003)

(1978 revision incorporated blast-furnace slag coarse aggregate, 1984 revision

blast-furnace slag fine aggregate.)

JIS A 5015 Iron and steel slag for road construction (instituted 1979, revised 1992)

2) National Specifications

Ferrous slag products are incorporated into a number of national specifications.

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Government agencies

(1) Portland blast-furnace slag cement and ground granulated blast-furnace slag

Regional development offices Common civil engineering specifications (instituted

2000)

MLIT Ports and Harbors Bureau Common port and harbor construction specifications

(issued 2004)

MLIT Housing Bureau 2004 common specifications for public housing

construction (issued 2004)

MLIT Housing Bureau Evaluation of fabrication methods employing concrete

using class B Portland blast-furnace slag cement in

underground sections (authorization of special

evaluation methods under the 2002 Residential

Quality Assurance Law)

MLIT Railway Bureau Railway structural design standards & commentary:

Concrete structures (issued 2004)

MAFF Rural Development Bureau Common civil engineering specifications: Common

specifications for facilities, machinery and


Prefectures Civil engineering contractor requirements

(2) Slag for concrete

MLIT Housing Bureau 2004 common specifications for public housing



(issued 2004)

Regional development offices Common civil engineering specifications (instituted

2000

MLIT Minister’s Secretariat Building and Repairs Department

2004 public building construction standards

specification (issued 2004)


(3) Slag for road building and concrete

MLIT Minister’s Secretariat Building and Repairs Department

2004 public building construction standards

specification (issued 2004)

Metropolitan Expressway Public Corporation

10

Common specifications for construction materials

(issued 2004)

MAFF Rural Development Bureau Common civil engineering specifications: Common

specifications for facilities, machinery and


(4) Slag for road building

Regional development offices Common civil engineering specifications (civil

engineering contractor requirements) (instituted

2000)



(issued 2004)

MLIT Railway Bureau Railway structural design standards & commentary:

Earth structures, SI unit edition (issued 2000)

(5) Slag for fertilizer

MAFF Blast furnace slag for ordinary fertilizer (1955 revision

of Fertilizer Control Law)

MAFF Basic-oxygen-furnace slag for ordinary fertilizer (1981

revision of Fertilizer Control Law)

3) Academic Society and Industrial Association Guidelines and Policies

Ferrous slag products have been incorporated into the guidelines and policies of interested

academic societies and industrial associations.

(1) Slag for concrete

Architectural Institute of Japan Policy and commentary on preparation design and

execution of concrete using Portland blast-furnace slag

cement (revised 2001)

AIJ Draft policy and commentary on execution of crushed

blast-furnace slag coarse aggregate concrete (1978)

AIJ Policy and commentary on execution with

blast-furnace slag fine aggregate (1983)

AIJ Policy and commentary on preparation design and

execution of concrete using ground granulated

blast-furnace slag (revised 2001)

Japan Society of Civil Engineers Execution policy on blast-furnace slag aggregate

concrete (1993)

11

JSCE Execution policy on concrete using ground granulated

blast-furnace slag (1996)

JSCE Design and execution policy on concrete using

electric-arc-furnace oxidizing slag aggregate (2003)

(2) Slag for road-building

Japan Road Association Asphalt paving guidelines (revised 1992)

Nippon Slag Association Policy on roadbed design and execution with

blast-furnace slag (revised 1982)

NSA Quality control guidelines for roadbed blast-furnace

slag (revised 1985)

NSA Policy on roadbed design and execution with steel slag

(revised 1985)

NSA Quality control guidelines for roadbed steel slag

(revised 1985)

NSA Policy on asphalt paving design and execution using

steel slag (revised 1982)

NSA Quality control guidelines for steel slag for hot asphalt

mixtures (revised 1983)

(3) Slag for port and harbor construction

The Japan Port & Harbor Association

Technical standards for port and harbor facilities, and

commentary (1999)

Coastal Development Institute of Technology & NSA CDIT & NSA

Handbook on using granulated slag in port and harbor

construction (1998)

Handbook on using steel slag in port and harbor

construction (2000)

Council on Promoting Recycling at Ports, Harbors and Airports

Policy on recycling technologies in port, harbor and

airport infrastructure (2004)

4) Law on Promoting Green Purchasing

By resolution of the Cabinet, the majority of ferrous slag products are qualified procurements

under the Law on Promoting Green Purchasing.

Portland blast-furnace slag cement 2001 30%+ blast-furnace slag

Blast-furnace slag aggregate 2002 Substitute for natural materials

12

Ferrous-slag admixture roadbed material 2002 Use of ferrous slag for road-building

Asphalt mixtures with ferrous-slag admixtures

2002 Use of ferrous slag as aggregate

Rock wool based on ferrous slag 2002 85%+ primary-material weight ratio

Granulated slag for earthmoving 2003 Quenching of molten blast-furnace

slag with high-pressure water

Ferrous slag for ground improvement 2004 Sand compaction pile (SCP) material

Electric-arc-furnace oxidizing slag aggregate

2005 Substitute for natural materials

13

3.2 Volumes Consumed

(1) Blast-Furnace Slag

Although blast-furnace slag had already been in use as landfill material, land forming

material and roadbed material for on-site roads in steelworks construction prior to 1965, its

use has since grown in such applications as roadbed material for ordinary roads, cement

material and aggregate for concrete, and since 1979 its use in landfills has fallen to zero. Slag

consumption for Portland blast-furnace slag cement has risen annually since the Second Oil

Shock of 1979 due to its advantages in resource saving and energy conservation and now

accounts for 60% of total consumption of blast-furnace slag.

Volume

(10,000 tons)

Figure 6 – Blast-furnace slag consumption

Cement

Roads

Earth work In-house

Concrete

14

(2) Steel Slag

Because the recycling of steel slag lagged that of blast-furnace slag, at four to five million tons

its use in landfills accounted for close to 40% of consumption in around 1980, but recycling

has since made progress and use in landfills now accounts for around 3% of the total volume

of steel slag generated.

Volume

(10,000 tons)

Figure 7 – Steel slag consumption

(3) Cumulative Field Sales of Ferrous Slag Product

According to Nippon Slag Association figures, cumulative field sales of ferrous slag product

since 1978 amount to 790 million tons, 610 million tons of blast-furnace slag product and 180

million tons of steel slag product. Ferrous slag products now have an established reputation

as serviceable materials and have gained acceptance in the markets for construction and civil

engineering materials.

Note

Ferrous slag product cumulative field sales amount from 1978 reach to 790 million tons, or

around 530 million m3 in volume. Meanwhile, total production of crude steel over the same

period was 2.8 billion tons, or around 350 million m3 in volume.

Cement

Roads

Earth work

Land reclamation

In-house

Other

Ground improvement

15

4. Utility and Usage of Ferrous Slag Products 4.1 Blast-Furnace Slag Products

(1) Properties and Primary Applications of Air-Cooled Blast-Furnace Slag Products

• Air-cooled blast-furnace slag is used as roadbed material because its favorable bite and

hydraulic properties promise high bearing capacity.

The use of recycled construction material as roadbed material is growing, and

composite roadbed materials with admixtures of ferrous slag to improve their physical

properties are also in use.

• Air-cooled blast-furnace slag is also used as coarse aggregate for concrete because it is

harmless with respect to alkali-aggregate reactions.

• The low alkalinity of air-cooled blast-furnace slag allows its use as cement clinker

material, and its fertilizer components (CaO, SiO2 and MgO) allow its use as lime

silicate fertilizer.

Table 1 – Properties and applications of air-cooled blast-furnace slag

Property Application

High bearing capacity due to bite and hydraulic properties Roadbed material

Little alkali-aggregate reaction due to low SiO2 content Coarse aggregate for concrete

Inhibition of alkali-aggregate reactions due to low Na2O and K2O Cement clinker material

Fertilizer components (CaO and SiO2) Lime silicate fertilizer

(2) Properties and Primary Applications of Granulated Blast-Furnace Slag Products

• Granulated blast-furnace slag is used as Portland blast-furnace slag cement material,

a Portland cement admixture and a concrete additive due to the latent hydraulic

properties promised by its pulverizing.

Compared to ordinary Portland cement, Portland blast-furnace slag cement enjoys

such advantages as the saving of natural materials through the use of a byproduct and,

in production, lower energy consumption and CO2 emissions (using 6.5 million tons of

slag in cement yields a reduction in CO2 emissions of 4.6 million tons). Concrete

employing Portland blast-furnace slag cement further offers superior durability by way

of its high resistance to salt damage and its inhibition alkali-aggregate reactions.

• Granulated blast-furnace slag is used as an earthwork material (in backfilling,

covering, embankments and sub-grade improvement, for example) due to its large

angle of internal friction in sandy form.

• Granulated blast-furnace slag is used as a fine aggregate for concrete due to its lack of

saline matter and other harmful substances.

With the tightening of regulations on the recovery of sea sand on the coasts of the Seto

16

Inland Sea, a comprehensive ban was placed on the recovery of sea sand in 2006, and

expectations are mounting for granulated blast-furnace slag fine aggregate as a

substitute material for sea sand.

• The fertilizer components (CaO, SiO2 and MgO) of granulated blast-furnace slag are

applied for its utilization as lime silicate fertilizer and ground improvement material.

Table 2 – Properties and applications of granulated blast-furnace slag products Property Application

Strong latent hydraulic properties resulting from quenching and pulverization

Portland blast-furnace slag cement material Portland cement admixture Concrete additive

Large angle of internal friction and light weight Earthwork material (e.g. backfilling, covering, embankment, sub-grades)

No chlorides and little alkali-aggregate reaction due to low SiO2 content

Fine aggregate for concrete

Fertilizer components (CaO and SiO2) Lime silicate fertilizer and ground improvement material

(3) Utilization of Blast-Furnace Slag

Figure 8 describes consumption, broken down by application, of air-cooled blast furnace slag

and granulated blast furnace slag in 2004.

• Consumption of air-cooled blast-furnace slag was 6.44 million tons, 4% used in-house,

14% for road-building in the leading field-sales application, 3% for cement and 2% for

earthwork and ground improvement.

• Consumption of granulated slag, on the other hand, was 18.88 million tons, 1% used

in-house, 59% for cement accounting for the majority as the leading field-sales

application, and of the remainder 9% as concrete aggregate and 4% for civil

engineering.

Figure 8 – Blast-furnace slag consumption by application (2004)

Fertilizer, other In-house

Ground improvement

Domestic cement

Exports Domestic cement 3%

Civil engineering 1%

Roads

Concrete 1%

Roads In-house 1% Fertilizer, other 1%

Air-cooled

25.32 m tons

Civil engineering ４%

Concrete

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4.2 Steel Slag Products

(1) Utility and Primary Applications of Steel Slag Products

• Steel slag is used as a roadbed material due to the high bearing capacity promised by

its hydraulic properties. Because it contains free lime (CaO), steel slag may expand

when it comes in contact with water. It is therefore employed after first being

stabilized.

• Taking advantage of its properties of having a greater mass of unit volume and greater

angle of internal friction than does natural sand, it is used as a sand substitute as a

ground improvement material (sand compaction pile material) in port and harbor

construction works.

• Steel slag is used as cement clinker material for its FeO content and, taking advantage

of its fertilizer components (CaO, SiO2, MgO and FeO), as fertilizer and a soil

improvement material.

Table 3 – Properties and applications of steel slag products Property Application

Hardness and abrasion resistance Aggregate for asphalt concrete

High bearing capacity and little water impact due to bite and hydraulic properties

Roadbed material

Large internal angle of friction Civil engineering material and ground improvement material (sand compaction material)

Chemical constituents (FeO, CaO and SiO2) Cement clinker material

Fertilizer components (CaO, SiO2, MgO and FeO)

Fertilizer and soil improvement material

(2) Utilization of Steel Slag

Consumption of steel slag in 2004 was 13.41 million tons, of which 26% was consumed

in-house. Of the remaining 74%, the primary applications were for civil engineering at 32%

and for road-building at 26%.

Figure 9 – Steel slag consumption by application (2004)

Land reclamation, other

Domestic cement Fertilizer, other

Civil engineering

Ground improvement

In-house

Roads 13.41 m tons

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4.3 Procurements Qualified Under the Law on Promoting Green Purchasing

• The reputation achieved by ferrous slag product for its environmental advantages and

its performance over many years of use led to the designation of the following ferrous

slag products in the qualified procurements list (of products contributing to the

mitigation of environmental load) of Law Concerning the Promotion of Procurement of

Eco-friendly Goods and Services by the State and other Entities (Law on Promoting

Green Purchasing), which came into force in 2001.

• Of total domestic sales of ferrous slag products in 2004, 74% were of those on the

qualified procurements list.

Table 4 – Ferrous slag products included in the Law on Promoting Green Purchasing

qualified procurements list Year Criteria

Portland blast-furnace slag cement 2001 30%+ Portland blast-furnace slag cement

Blast-furnace slag aggregate 2002 Substitute for natural material

Roadbed material with ferrous slag admixture

2002 Use of ferrous slag for road-building

Asphalt mixture with ferrous slag admixture

2002 Use of ferrous slag as aggregate

Rock wool produced from ferrous slag 2002 85%+ primary-material weight ratio

Granulated slag for civil engineering (granulated slag for harbor and port construction works)

2003 Quenching of molten blast-furnace slag with high-pressure water

Steel slag for ground improvement (steel slag for harbor and port construction works)

2004 Sand compaction pile (SCP) material

Electric-arc-furnace oxidizing slag aggregate

2005 Concrete aggregate with electric-arc-furnace oxidizing slag as primary material

4.4 Recycling Technology Policy for Port and Airport Infrastructure: Ferrous Slag Products at

MLIT Ports and Harbors Bureau

General Rule 1.2 Application of the MLIT policy states, “’Industrial waste’ includes such

material as ferrous slag, coal ash and nonferrous metal slags, and where these are employed

as useful materials for such purposes as concrete material, roadbed material and civil

engineering material, they shall not constitute waste under the terms of the Waste

Management Law.”

4.5 Technology Development for Use in Marine Environment Remediation

• Blocks for use in marine environments (fly-ash-slag concrete, ferrous-slag hydrated

solids, ferrous-slag carbonate solids) using ferrous slag as an input material have been

19

developed and their application in actual marine environments has begun.

• Using ferrous slag as a water and bottom-sediment decontaminant, development of the

technology as a means of marine environment remediation continues, with such efforts

as to proliferate oceanic phytoplankton and fix CO2.

Empirical testing of marine environmental remediation is pursuing the following two

avenues.

1) Development of technology for improvement of bottom sediment and water quality

in closed brackish waters

Marino-Forum 21 is conducting sand-cover testing, initiated in 2003, with

granulated slag with the objective of forming a shijimi bivalve (Corbicula japonica)

grounds in Lake Shinji.

2) Research and development in slag utilization

Development of the following technologies is underway with the assistance of grants

from the Ministry of Economy, Trade and Industry. (2004-2007)

(1) Development of environmental remediation technology for upright sea walls

using ferrous-slag hydrated solids

(2) Development of technology to expand the applications of ferrous-slag hydrated

solids

(3) Development of steel-slag stabilization and reformation technology using coal

ash

(4) Studies on and evaluation of the stability and environmental benefits of using

steel slag in marine waters

4.6 Law for Promotion of Effective Utilities of Resources

The Law for the Promotion of Utilities of Recycled Resources of 1991 designated ferrous slag

as a designated byproduct, and the Law for Promotion of Effective Utilities of Resources of

2000 designated the steel industry as a designated resource-saving industry and called on it

to work to contain the generation of ferrous slag as a byproduct and to promote its use as a

recyclable resource.

4.7 Instances of Use in Major Construction Projects

• Ferrous slag products have long been used in large volumes in major public works

projects, such as airport construction, exploiting their properties described above. The

most important projects of the past ten years are as follows.

1) Construction during recovery from the Great Hanshin Earthquake (1996, 1.10

million tons of granulated slag product)

2) Ground improvement (SCP) works in the Hiroshima Port Renaissance 21 project

(begun 1998, 4.00 million tons of steel slag product)

20

3) Soft ground improvement (sand matting) works at Shin-Kitakyushu Airport

(2000-02, 1.50 million tons of granulated slag product)

4) Chubu International Airport (2001-04, 1.54 million tons of blast-furnace slag

products and 320,000 tons of steel slag product; see next page)

5) Kobe Airport (2003-04, 1.60 million tons of ferrous slag product, including 500,000

tons of granulated slag product and 1.10 million tons of steel slag product)

• The recent example of Chubu International Airport

* Opened in February 2005, Chubu International Airport Centrair engaged with

environmental considerations with the aim of being a leading environmental

airport.

* As part of this effort, around 1.90 million tons of ferrous slag product were employed

in runway and taxiway construction, in formation of the airport island and in such

applications as apron subgrade material, fine aggregate for concrete, loading

embankment material and dredged-spoil solidifier.

21

Table 5 – Consumption of ferrous slag products at Chubu International Airport by application

Application Granu- lated slag

Air- cooled slag

Steel slag

Total (‘000 tons)

1 Revetment blocks

Granulated slag for Portland blast-furnace slag cement, fine aggregate for concrete

30 0 0 30

2 Loading embankment

Green buffer covering, loading embankment for petroleum tanks

0 0 320 320

3 Dredged-spoil solidifier

Granulated slag for Portland blast-furnace slag cement

170 0 0 170

4 Aprons (parking lot)

Hearth material, fine aggregate, granulated slag for Portland blast-furnace slag cement

110 150 0 260

5 Runway & taxiway

Roadbed material, subgrade material

0 710 0 710

6 Terminal building, other structures

Granulated slag for Portland blast-furnace slag cement, fine aggregate for concrete

110 0 0 110

7 Circuit road, parking lot

Temporary roadbed material 0 260 0 260

Total slag consumption 420 1,120 320 1,860

Photo 1 – Steel slag products used in the construction of Chubu International Airport

(Centrair)

(1) Revetment blocks

(2) Loading embankment

(3) Dredged-spoil solidifier

(5) Runway & taxiway

(4) Aprons

(6) Terminal building, other structures

(7) Circuit road, parking lot

22

4.8 Chemical Composition of Ferrous Slag Products and Their Conformance to

Environmental Standards

(1) Chemical Composition

• Iron and steel products are produced with iron ore, coal to reduce the iron ore and, as a

refining agent, limestone produced in Japan, and the ferrous slag byproduct is also

produced from these input materials.

• The composition of ferrous slag, which is the material for ferrous slag products,

resembles those of natural rock and Portland cement as shown in Table 6, its primary

constituents being lime (CaO) and silica (SiO2). The lime (CaO) in slag is soluble in

water and exhibits the same alkalinity as cement and concrete.

• Because it is generated at temperatures of 1,200°C and greater, ferrous slag contains

no organic matter whatsoever.

Table 6 – Chemical composition of ferrous slag (Unit: %) Ferrous slag Comparisons

Constituent Blast-furnace slag

Steel slag Mountain soil Andesite Portland cement

SiO2 33.8 13.8 59.6 59.6 22.0

CaO 42.0 44.3 0.4 5.8 64.2

Al2O3 14.4 1.5 22.0 17.3 5.5

T-Fe 0.3 17.5 -- 3.1 3.0

MgO 6.7 6.4 0.8 2.8 1.5

S 0.8 0.07 0.01 -- 2.0

MnD 0.3 5.3 0.1 0.2 --

TiO2 1.0 1.5 -- 0.8 --

Source: Nippon Slag Association

(2) Conformance to Environmental Standards

1) Environmental JIS and Environmental Standards for Ferrous Slag Product

• Ferrous slag quality has already been specified in JIS standards as a civil engineering

material, and as it has been designated in the qualified procurements list of Law

Concerning the Promotion of Procurement of Eco-friendly Goods and Services by the

State and other Entities (Law on Promoting Green Purchasing), the vast majority are

utilized effectively. Given the lack of quality standards addressing environmental

safety, however, an Environment Ministry notification, KMT-44 of 28 March 2001

issued on the occasion of the revision of the environmental quality standards for soil,

stated, “While soil environmental standards and measurement methods are invoked

for safety evaluations, evaluations must be performed that are appropriate and suited

to their current form and the context of their use.” In March 2005 JIS K 0058-1 and -2

“Test methods for chemicals in slags” Parts 1 and 2 were instituted, and work is

23

underway to incorporate ferrous slags for road-building and other specific ferrous slag

products into the additions and revisions being made to environmental sections in JIS

standards.

• Tables 7 and 8 give examples of elution test results and content test results on ferrous

slag products in their forms of use in accordance with JIS K 0058-1 and -2 “Test

methods for chemicals in slags” Parts 1 and 2. Environmental reference values for

ferrous slag products are to be specified in forthcoming JIS standards for ferrous slag

products. Those given the tables below are reference values from the environmental

quality standards for soil and the Soil Contamination Countermeasures Law.

The elution test measurements and content test measurements for each of the

examples of ferrous slag products used here meet those specified in the environmental

quality standards for soil and the Soil Contamination Countermeasures Law.

Table 7 – Elution test results for ferrous slag products according to Environmental JIS Law

(unit: mg/L)

Blast-furnace slag products Steel slag products Sub-

stance Ref value: Soil elution standard

Air-cooled slag

Granulated slag

BOF slag EAF slag

Cd 0.01 max <0.001 <0.001 <0.001 <0.001

Pb 0.01 max <0.001 <0.001 <0.001 <0.001

Cr6+ 0.05 max <0.02 <0.02 <0.02 <0.02

As 0.01 max <0.001 <0.001 <0.001 <0.001

T-Hg 0.0005 max <0.0002 <0.0002 <0.0002 <0.0002

Se 0.01 max <0.001 <0.001 <0.001 <0.001

F 0.8 max 0.2 0.1 <0.1 <0.1

B 1.0 max <0.1 <0.1 <0.1 <0.1

N.B. “<” represents a result below the quantitative limit of the analysis and indicates “not

detectable”.

Source: “Report on Study of Standardization of Energy-Use Rationalization Systems”

(Standardization studies on standardization of Methods for Testing for Chemical

Substances in Recyclable Materials and Products)

24

Table 8 – Content test results for ferrous slag products according to Environmental JIS Law

(unit: mg/kg) Blast-furnace slag products Steel slag products

Sub- stance

Ref value: Soil content standard

Air-cooled slag

Granulated slag

BOF slag EAF slag

Cd 150 max <0.5 <0.5 <0.5 <0.5 Pb 150 max <5 <5 <5 <5

Cr6+ 250 max <2 <2 <2 <2 As 150 max <1 <1 <1 <1

T-Hg 15 max <0.2 <0.2 <0.2 <0.2 Se 150 max <1 <1 <1 <1 F 4000 max 890 490 850 190 B 4000 max 110 130 90 110


detectable”.

Source: “Report on Study of Standardization of Energy-Use Rationalization Systems”

(Standardization studies on standardization of Methods for Testing for Chemical

Substances in Recyclable Materials and Products)

2) Environmental Quality Standards for Soil and Ferrous Slag Products

• Conventionally environmental safety has been evaluated by elution testing in

accordance with environmental quality standards for soil when using ferrous slag

products on land. Table 9 is an example of slag product measurements in accordance

with the testing methods of the environmental quality standards for soil (The

announcement No. 46 by the Environmental Agency).

Measurements in these elution test results were also either not detectable or meet the

reference values of the environmental quality standards for soil (The announcement No.

46 by the Environmental Agency).

Table 9 – Example of elution test measurements for ferrous slag products according to

environmental quality standards for soil (KanKoku No. 46)

(Unit: mg/L) Blast-furnace slag products Steel slag products

Sub- stance

Environmental quality standards for soil

Air-cooled slag Granulated slag BOF slag

Cd 0.01 max <0.005 <0.005 <0.005 Pb 0.01 max <0.001 <0.001 <0.001

Cr6+ 0.05 max <0.01 <0.01 <0.01 As 0.01 max <0.001 <0.001 <0.001

T-Hg 0.0005 max <0.0005 <0.0005 <0.0005 Se 0.01 max 0.004 <0.002 <0.002 F 0.8 max 0.26 0.16 0.62 B 1.0 max 0.12 0.10 0.02

25


detectable”.

Source: Nippon Slag Association

3) Dredged Soil Standards and Ferrous Slag Products

• When using ferrous slag products in marine environments or reclaimed land,

environmental safety is evaluated with dredged soil standards in accordance with the

Marine Pollution Prevention Law. Table 10 gives example results from elution testing

in accordance with the announcement No. 14 by the Environmental Agency on test

methods for dredged soil. All save fluorides were not detectable, and the measurements

for fluorides meet the reference value for dredged soil.

4) Alkalinity

• Ferrous slag contains CaO, which reacts with water to produce slaked lime (Ca(OH)2).

Because this dissolves into Ca2+ and OH-, it results in a higher pH. Granulated

blast-furnace slag has a pH of around 10, air-cooled blast-furnace slag a pH of around

11 and steel slag a pH of around 12, each having an alkalinity roughly equivalent to or

lower than crushed concrete rubble, which has a pH of around 12.

• Granulated blast-furnace slags have been used in large volumes in port and harbor

construction works, not least as back-fill material (ca. 1.20 million tons) for

breakwaters in construction during recovery from the Great Hanshin Earthquake.

Measurements are taken of the pH of the surrounding waters in such cases. These

increased only by 0.1 to 0.2 in the vicinity of sections where work with granulated

blast-furnace slag was performed, confirming that this slag has almost no impact on

the pH of surrounding marine waters.

• Air-cooled blast furnace slags and steel slags are used primarily on land, especially as

roadbed material. They have pH levels of around 11 and 12, respectively, equivalent to

or below those of recyclable roadbed material (crushed concrete rubble) and cements

that are often used as earth improvement material.

As Japanese soil is generally acidic, alkali eluents from slag are absorbed into the soil

and neutralize it. When water coming into contact with slag flows directly into a body

of water without passing through the soil, neutralization and like measures are taken

as necessary.

26

Table 10 – Example of elution tests on ferrous slag products according to dredged soil

standards (the announcement No. 14 by the Environmental Agency) (Unit: mg/L)

Blast-furnace slag products Steel slag products

Substance Evaluation

criterion

Quanti- tation limit

Air-cooled slag

Granulated slag

EAF slag

Alkyl mercury compounds ND 0.0005 ND ND ND

Hg compounds 0.005 max 0.0005 ND ND ND

Cd compounds 0.1 max 0.001 ND ND ND

Pb compounds 0.1 max 0.005 ND ND ND

Organophosphorus compounds

1 max 0.1 ND ND ND

Cr6+ compounds 0.5 max 0.4 ND ND ND

As compounds 0.1 max 0.005 ND ND ND

Cyanide compounds 1 max 0.1 ND ND ND

PCB 0.003 max 0.0005 ND ND ND

Cu compounds 3 max 0.005 ND ND ND

Zn compounds 5 max 0.01 ND ND ND

Flourides 15 max 0.1 0.3 0.26 0-4.4

Trichloroethylene 0.3 max 0.002 ND ND ND

Tetrachloroethylene 0.1 max 0.005 ND ND ND

Be compounds 2.5 max 0.01 ND ND ND

Cr compounds 2 max 0.04 ND ND ND

Ni compounds 1.2 max 0.1 ND ND ND

V compounds 1.5 max 0.1 ND ND ND

Organochlorine compounds 40 max 0.1 ND ND ND

Dichloromethane 0.2 max 0.1 ND ND ND

Carbon tetrachloride 0.02 max 0.1 ND ND ND

1,2-dichloroethane 0.04 max 0.1 ND ND ND

1,1-dichloroethylene 0.2 max 0.1 ND ND ND

Cis-1,2-dichloroethylene 0.4 max 0.1 ND ND ND

1,1,1-trichloroethane 3 max 0.1 ND ND ND

1,1,2-trichloroethane 0.06 max 0.1 ND ND ND

1,3-dichloropropane 0.02 max 0.1 ND ND ND

Thiram 0.06 max 0.1 ND ND ND

Simazine 0.03 max 0.1 ND ND ND Thiobencarb 0.2 max 0.1 ND ND ND

Benzene 0.1 max 0.1 ND ND ND

Se compounds 0.1 max 0.1 ND ND ND

Dioxin elution: Measurements were all TEQ zero for air-cooled blast-furnace slag, granulated

blast-furnace slag and steel slag.

Sources: Blast-furnace slag products – Nippon Slag Association, steel slag products -- Handbook

on using granulated slag in port and harbor construction (Coastal Development Institute

of Technology and Nippon Slag Association)

27

5. Control of Ferrous Slag from Generation to Customer Use 5.1 Production Control of Ferrous Slag Product

• Slag is generated in several steelmaking processes: the pig iron manufacturing and

steelmaking processes with blast furnaces and the steelmaking process with electric

arc furnaces.

• Although these industrial processes were originally designed solely for the production

of pig iron and steel, one objective of these processes today is to produce ferrous slag

product of high quality.

• In order to produce product that conforms to application-specific standards (JIS and

other standards), steelmakers have devised the following provisions in their production

processes.

1) Selection of input materials so as to control the quality of ferrous slag product, as

well as the quality of ferrous product (materials processes)

2) Selection of refining conditions appropriate to both iron and slag (melting processes)

3) Slag processing processes to satisfy slag product standards, including vitrification

rate and expansion stability (cooling processes)

4) Quality assurance by means of ageing as well as crushing and sieving for

granularity control in order to produce the variety of slag products (processing

processes)

5) Shipment inspections in order to assure the quality of slag product (shipment

process and quality inspection)

• Only 1 percent of ferrous slag generated is not processed into product; that one percent

is segregated and controlled as of the stage at which slag is generated and

appropriately controlled and processed as waste.

28

(1) Blast-furnace slag product production process control

Process Means of controlling quality

QC characteristics

Raw material processes

Chemical composition

Smelting processes (blast furnace)

Material mixture (cement basicity) Molten slag temperature (initial cooling temperature)

Chemical composition CaO SiO2 Al2O3 MgO, other Cement basicity Porosity

Cooling method (cooling speed) 1) Quenching (vitrification) • Quenching and

granulation by high-pressure water injection

• Initial cooling temperature control

Vitrification rate Granularity Absolute-dry density Water absorption (porosity)

Cooling processes (solidification)

2) Air-cooling (crystallization) • Cooling with air

and sprinkling

Strength (e.g. modified CBR) Absolute-dry density Mass of unit volume Water absorption (porosity)

Processing processes

Processing Mixture Ageing Coating

Removal of magnetic matter Granularity Granularity Coloration (citrine) Consolidation control

Shipment processes Quality inspection

Coke, coal Iron ore, sintered ore Limestone, dolomite ore

Hot metal Molten blast-furnace slag Blast-furnace gas

Constituent inspection

Air-cooled slag Air cooling (crystallization) with

atmosphere and sprinkling in dry pits

Granulated blast-furnace slag Quenching and granulation (<5 mm)

with initial cooling temperature control and high-pressure water in ex-furnace granulation equipment

Granulated slag Quenching and granulation (<5 mm), i.e. vitrification,

with high-pressure water in granulation equipment

Processing

Coating Ageing (citrinization)

Mixture

Coarse aggregate for concrete Composition Granularity, fineness Absolute-dry density Absorption, mass by

unit volume

Roadbed material Coloration,

granularity Moisture content Mass by unit

volume Modified CBR

Fine aggregate for concrete Composition Granularity, fineness Absolute-dry density Absorption, mass by

unit volume

Earth working material

Cement material Cement

basicity

Steel slag products

Quality inspection



Processing Processing

Quality inspection

Quality inspection

Quality inspection

Quality inspection

Color evaluation

Blast furnace

29

(2) Steel slag product production process control (basic oxygen furnace)

Process Means of controlling quality

QC characteristics

Raw material processes

Hot-metal composition ratio Scrap screening

Smelting processes (BOF)

Refining conditions defined appropriate to steel and scrap both (satisfying quality for both steel and scrap product) Oxygen-stream

speed (top-blowing & bottom-blowing)

Quicklime volume (basicity)

Limit on dolomite use for furnace protection

Limit on refining promoter (fluorite)

Chemical composition CaO SiO2 FeO P2O5 MgO, other Expansion stability (CaOfree)


Cooling (crystallization) by air and sprinkling

Crystal structure Expansion stability Strength (e.g. modified CBR) Mass by unit volume Absorption (porosity) Abrasion reduction


Processing Mixture Ageing (steam, atmosphere)

Removal of magnetic matter Granularity Granularity Expansion characteristics

Shipment processes Quality inspection

Roadbed material Granularity Water content Mass by unit

volume Modified CBR Immersed

expansion ratio

Group improvement material

Earth working material

Fertilizer

Steel slag products

Scrap Hot metal Additives (quicklime, other)

Finery (preliminary treatment, basic oxygen furnace)

Steel Molten steel slag LD gas Non-product slag

Cooling with atmosphere and sprinkling (slag pit or slag ladle)

Cooling with atmosphere & sprinkling (segregation

control in separate yard)

Processing Processing Digging

Ageing (steam, atmosphere)

Quality inspection

<Issue manifest>

Landfill disposal, etc

Quality inspection

Quality inspection

Quality inspection


30

(3) Steel slag product production process control (electric arc furnace example)

Process Means of controlling quality QC characteristics Raw material processes

Scrap screening Additives

Smelting processes (electric arc furnace)

Refining conditions defined appropriate to steel and scrap both (satisfying quality for both steel and scrap products Oxygen volume Quicklime volume

(basicity) Deoxidation promoter

(AL-D) volume Limit on refining promoter

(fluorite)

Chemical composition CaO SiO2 FeO, other Expansion stability (CaOfree)


Cooling with atmosphere and sprinkling

Crystal structure Expansion stability Strength (e.g. modified CBR) Mass by unit volume Absorption (porosity) Abrasion reduction


Processing Mixture Ageing

Removal of magnetic matter Granularity Granularity Expansion characteristics Physical characteristics Granularity Optimal water

content Maximum dry density Modified CBR Mass by unit volume Uniaxial compressive

strength Immersed expansion

rate Shipment processes Quality inspection

Additives (quicklime, powdered coke)

Melting furnace (electric arc furnace)

Non-product slag Slag reformate

Molten steel slag (oxidizing slag)

Molten steel slag (reducing slag)

Cooling with atmosphere and sprinkling

(slag pit or slag ladle)

Cooling with atmosphere and

sprinkling (slag pit or slag ladle)

Cooling with atmosphere and

sprinkling (segregation control

in separate yard)


Mixing

Ageing

Expansion stability

Quality inspection

<Issue manifest> Steel slag products

Roadbed material Landfill

disposal, etc.

Alloy Scrap

31

5.2 Control of Ferrous Slag Product from Shipment to Customer

• Ferrous slag products are traded as products (valuable resources) at their local market

value on the basis of negotiations with customers.

• Nippon Slag Association released a new edition of the “Guidelines on Control of Iron

and Steel Slag Product” on July 28 of this year from a perspective of ensuring the

appropriate utilization of ferrous slag product and preventing problems arising from it,

and these are now being incorporated into corporate manuals.

The coverage of the Guidelines is as follows.

Guidelines on Control of Iron and Steel Slag Product

1. Objectives

2. Scope of Application

3. Member Obligations

4. Quality Control of Iron and Steel Slag Product

5. Selling Control of Iron and Steel Slag Product

5-1. Prior to order acceptance

5-2. Order acceptance and delivery

5-3. Work execution

5-4. Transport of iron and steel slag product

6. Follow-up Surveys Subsequent to Completion of Execution

7. Handling Problems and Concerns about Problems

8. Verification of Manual Utilization and Observance, and Corrective Action

Notes Concerning These Guidelines

These Guidelines set forth policy with respect to members and do not constitute any portion of

specific contractual matter between members themselves or between members and third

parties.

Nippon Slag Association makes no guarantee that environmental impact or other problems may

be averted by means of usage and contract in accordance with these Guidelines.

32

6. Summary History of Recycling

• Ferrous slag is generated in the course of steel production, and ways of recycling slag

have been sought throughout the long history of the iron and steel industries. Their

traditional use as landfill material has been nearing its limit with the pause in

construction of steelworks and the growing social demand for resource saving and

energy conservation since around 1970. The steel companies and the industry have

since taken on the recycling of ferrous slag as among their important management

challenges and have promoted the development of technology, the maintenance of

production facilities and certification for ferrous slag products.

Certification

• Four ferrous slag products are specified in JIS, and JIS-specified product accounts for

64% of field sales volume. The Law on Promoting Green Purchasing qualified

procurements list also includes eight ferrous slag products, which account for 74% of

field sales volume. Further, ferrous slag is treated as distinct from industrial waste in

the MLIT’s “Policy on recycling technologies in port, harbor and airport infrastructure,”

and large amounts of ferrous slag have long been used in public works projects at the

national and local levels.

• The Law for Promotion of Effective Utilities of Resources of 2000 designated the steel

industry as a qualified resource-saving industry, and it is now working to contain the

generation of ferrous slag as a byproduct and to promote its use as a recyclable

resource.

Utilization

• Of ferrous slag generated in blast-furnace and steelmaking processes, 12% is consumed

in-house at the steelworks, and the remaining 88% is marketed as ferrous steel product,

used in cement, roadbed material, ground improvement material, civil engineering

material and fertilizer. Only 1 percent is not fit for product purposes and processed as

industrial waste in landfills (manifest processing).

• Cumulative field sales of ferrous slag product have reached 790 million tons (610

million tons of blast-furnace slag product and 180 million tons of steel slag product)

since 1978, according to Nippon Slag Association figures. Ferrous slag products have

now secured a reputation as serviceable materials and are generally accepted in the

market for construction and civil engineering materials.

Control from Generation to Customer Use

• Ferrous slag product is subject to appropriate quality control and regulation from the

33

selection of the input materials generated through production and processing processes

in line with JIS standards and customer physical and chemical requirements and is

subject to quality assurance in the form of shipment inspections. Although steelmaking

processes were originally designed solely for the production of pig iron and steel, one

objective of these processes today is to generate the slag required to produce ferrous

slag product of high quality and they are important operational elements in steel

production and in equipment design. Ferrous slag product is subject to rigorous control

throughout all processes from the stage of slag generation to the production and sale of

ferrous slag product.

• Ferrous slag products are traded as products (valuable resources) at their local market

value on the basis of negotiations with customers. Nippon Slag Association has

established an “Iron and Steel Slag Product Control Manual” for sales to ensure

appropriate utilization by customers.

Significance of Slag Operations in the Steel Industry

• Thus, steelmakers have for many years taken responsibility in developing technology

for the effective utilization of ferrous slag as an iron byproduct, developing markets for

it and controlling its sale and distribution.

• We are confident that the recycling of ferrous slag, its effective utilization and turning

it into high-value-added product are important elements of steelmakers’

competitiveness, that ferrous slag has contributed to resource saving and measures to

combat global warming and that it contributes to the formation of a society well

grounded in the practice of recycling.

1

Annex

Chronology of Ferrous Slag Activities

Technology Development & Certification Year

Blast-furnace slag Steel slag Other Activities

Pre- 1978

• 1976: NSA institutes “Draft policy on roadbed design and execution with blast-furnace slag coarse aggregate”

• 1977: NSA institutes “Draft policy on crushed blast-furnace slag coarse aggregate concrete”

• 1976: JIS A 5011 “Slag aggregate for concrete” instituted

• 1966: Six selling companies form the Slag Products Study Group in Osaka

• 1968: Renamed the Japan Slag Group

• 1976: Renamed the Japan Slag Society; Japan Iron and Steel Federation

• 1972: Blast-furnace slag JIS standardization committee formed

• 1976: Slag resource application committee formed

• 1977: JISF PR pamphlet “Iron & Steel Slag” issued

1978

• JSCE institutes “Draft policy on design and execution with crushed blast-furnace slag coarse aggregate concrete”

• JIS A 5308 “Ready-mixed concrete” revised

• Crushed blast-furnace slag recognized as material on basis of Construction Standards Law

• JRA asphalt paving guidelines revised (ferrous slag included)

• Japan Slag Society progressively dissolved, Nippon Slag Association formed with steelmakers (20 members total)

• “Report on effective utilization of ferrous slag in the context of resource saving and energy conservation” completed by Science & Technology Agency’s Resource Study Group

• JISF study group on use of ferrous slag overseas visits Europe, North America

1979

• JIS A 5015 “Iron and steel slag for road construction” instituted

• Ministry of Construction, Building & Repairs Dept revises common construction work specifications (concrete)

• AIJ includes coarse

• Technical training sessions held (annually going forward)

• Ferrous Slag News inaugural issue (3-4 issues annually)

• Initial publication of “Blast-Furnace Slag Market Statistics” and “Steel Slag

2

aggregate in building work standards specification JASS-5 Ferroconcrete Work

• JIS R 5210 “Portland cement” and JIS R 5211 “Portland blast-furnace slag cement” revised

Production Survey”

1980

• MEPC revises civil engineering materials specifications (for roads, concrete)

• Housing & Urban Development Corp revises common construction specifications (for roads, concrete)

• JSCE revises concrete standards specification

• Hyogo prefecture releases “Practical testing of HMS roadbed material”

• Ground improvement technology using granulated slag developed

• Steel slag expansion stability evaluation test methods harmonized

• Initial publication and promotion of technical documentation “Utilization of Ferrous Slag in Portland Blast-Furnace Slag Cement”

1981

• JIS A 5012 “Granulated blast-furnace slag fine aggregate for concrete” instituted

• “Guidelines on quality control of blast-furnace slag for roadbeds” drafted

• Kinki Regional Construction Bureau releases “Experimental work with concrete using blast- furnace slag fine aggregate” (started 1979)

• Fertilizer Control Law revised (certification of BOF slag, special fertilizer)

• Studies on steel slag expansion stability evaluation test method reproducibility

• “Ferrous Slag Handbook” published

1982

• JSCE institutes “Draft policy on design and execution of concrete using blast-furnace slag fine aggregate”

• “Policy on roadbed design and execution with blast-furnace slag” revised

• “Policy on asphalt pavement design and execution using steel slag” instituted

• JISF study group on steel slag application technologies visits North America

3

1983

• AIJ institutes “Policy on concrete execution using blast-furnace slag fine aggregate”

• Ministry of Construction Housing Bureau approves blast-furnace slag fine aggregate as material

• “Quality control guidelines for steel slag for cured asphalt admixture” instituted

• JRA study on abrasion resistance of BOF-slag asphalt concrete

• Steel slag expansion stability evaluation test methods compiled

• MITI Minister’s Award bestowed on corporations making contributions to recycling

1984

• AIJ includes fine aggregate in building work standards specification JASS-5 Ferroconcrete Work

• Response to citrine incidents involving blast- furnace slag (review of quality assurance system)

• Japan Soil Association compiles “Experimental studies on agricultural applications of ferrous slag” (conducted continuously since 1980)

• Public Works Research Institute and Public Works Research Center compile joint research on road-building material applications of ferrous slag (conducted since 1979)

• Regular work of JISF Slag Recycling Committee transferred to NSA

• Consolidation of statistics including cement supply and demand, slag supply volume, etc.

• Initial publication of “Steel Slag Market Statistics”

• Initial publication of “Steel Slag Statistics Annual”

• Steel Slag Bulletin (monthly) inaugurated, PR activities

1985

• JIS A 5015 “Iron and steel slag for road construction” revised

• “Guidelines on quality control of blast-furnace slag for roadbeds” revised

• “General ageing tests for blast-furnace slag”

• “Validity of alkali-aggregate reaction of blast-furnace slag coarse aggregate” verification

• “Roadbed design and execution guidelines for steel slag” instituted

• “Roadbed steel slag quality control guidelines” instituted

• Field survey conducted on roadbed material production and quality control

• Studies of New Kansai Airport and Trans-Tokyo Bay Highway major projects

• “Granulated slag for civil engineering” PR pamphlet issued

1986

• PWRI & PWRC complete and compile “Joint studies to verify inhibition of alkali aggregate reactions” (initiated 1985)

• JSCE revises “Reinforced Concrete Specification” and institutes “Draft standard ground

• Experimental testing of steel slag roadbed material performed by Aichi and Hyogo prefectures, Kobe city and Kyushu Regional Construction Bureau

• Technical briefing held on Portland blast-furnace slag cement and steel slag roadbed material

• Studies of Minato Mirai 21 and Akashi Kaikyo Bridge major projects

• Joint research results presented to 7th

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granulated blast-furnace slag for concrete”

• Ministry of Construction notification on “Provisional measures for alkali-aggregate reactions”

• JIS R 5210 “Portland cement” and JIS A 5308 “Ready-mixed concrete” revised

• Fertilizer Control Law revised: “slag silicate fertilizer” (ordinary fertilizer)

International Conference on Alkali-Aggregate Reactions (Canada)

1987

• JSCE institutes “Draft policy on design and execution of concrete using ground granulated blast-furnace slag”

• CDIT compiles “Joint research on granulated slag in port and harbor construction works” (initiated 1985)

• Joint research with Hokkaido Regional Development Bureau completed on alkali-aggregate reactions (initiated 1986)

• Tohoku University research into blast-furnace slag engineering mechanisms

• Experimental testing of steel slag roadbed materials by Osaka and Himeji cities

• PR activities for Portland blast-furnace slag cement • “Properties and Utility of Steel Slag” PR pamphlet issued

1988

• Research on utilization of ground granulated blast- furnace slag

• Tohoku University research on establishing optimal ageing methods for blast-furnace slag

• Research into utilization of granulated slag for civil engineering material

• Joint research with Building Research

• JRA revises “Asphalt paving guidelines”

• Promotion of JSCE “Design and execution policy for ground granulated blast-furnace slag” • Government-industry coordination for stable slag supply • Study of high-standard arterial road major project • Trend assessment and analysis of slag competitors • Field survey conducted of

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Institute on high-strength concrete in new reinforced-concrete structures

• Research into rapid analysis methods for blast-furnace slag

roadbed material production and quality control

1989

• 8th International Conference on Alkali- Aggregate Reactions

• “Handbook on Using Granulated Slag for Port and Harbor Construction Works” drafted, lecture presented

• Study of ground granulated blast-furnace slag contracted to AIJ

• Joint research on RCD technology initiated with Japan Institute of Construction Engineering

• Revision of policy on blast-furnace slag aggregates contracted to JSCE

1990

• “Manual for Use of Granulated Slag for Civil Engineering” drafted

• Research initiated into water and bottom sedi-ment purification using steel slag (red tide and blue tide countermeasures) (Water & Bottom Sediment Purification Research Evaluation Committee established)

• Special cement including ground granulated slag used in work connected with Akashi Kaikyo Bridge

• Ground granulated blast-furnace slag and Portland blast-furnace slag cement certified as EcoMark products

• Promotion of Portland blast-furnace slag cement included in Global Warming Prevention Plan adopted by Council of Ministries for Global Environment Conservation

• Promotional PR for Portland blast-furnace slag cement, other

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products, with government authorities

• “Properties and Utility of Steel Slag” pamphlet revised

1991

• Japan Testing Center for Construction Materials forms JIS revision drafting committee for slag aggregate for concrete

• Coal-ash-mixed BOF slag roadbed material test equipment at Hyogo prefecture

• Practical testing of EAF slag by Hyogo prefecture

• EAF slag roadbed material test equipment at Ehime prefecture

• Law for the Promotion of Utilization of Recycled Resources (“Recycling Law”) enacted (ferrous slag designated a “qualified byproduct”)

1992

• JIS A 5011 “Slag aggregate for concrete” revised (blast-furnace slag coarse aggregate and fine aggregate standards unified, ferronickel slag fine aggregate standard added)

• JIS A 5015 revised from “Road-building slag” to “Iron and steel slag for road construction” (due to standardization of ferrous slag)

• Research initiated on application of steel slag to harbor and port civil engineering works materials

• Research into expanded utilization of steel slag in cement input materials

• BOF slag roadbed material test equipment (Osaka prefecture)

• JISF formulates action policy on environment

• Production initiated of reinforced concrete using ground granulated slag for Trans-Tokyo Bay Highway Corp.

1993

• JIS drafting committee formed for ground granulated blast-furnace slag for concrete

• Revision of policy on ground granulated blast- furnace slag contracted to JSCE

• Research into high- flow concrete contracted to JIA

• Research into high- flow concrete contracted to JSCE

• Chugoku Regional Construction Bureau

• “Report on water and bottom-sediment purification testing with steel slag” drafted by Water & Bottom Sediment Purification Research Evaluation Committee

• Steel Slag Sand-Cover Utilization Research Committee established (joint research with CDIT)

• Committee on Technical Research into Application of Steel Slag to Port & Harbor Construction


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certification of granulated slag for civil engineering

Works inaugurated (joint research with CDIT)

• Composite-slag roadbed material test equipment at Chiba, Ibaragi prefectures

• Certification of complex-slag roadbed material with recycled concrete and ferrous slag by Kitakyushu city

• Certification of EAF- slag upper-layer roadbed material by Osaka prefecture

• Certification of steel slag roadbed material by Aichi, Hyogo, Okayama, Hiroshima prefectures

1994

• Drafting of policy on ground granulated blast- furnace slag contracted to AIJ

• Certification of composite-slag roadbed material by Chiba, Ibaragi prefectures

• Market coordination to meet slag requirements in connection with recovery from Great Hanshin- Awaji Earthquake

• Steel slag used in landfill compartment banking in artificial in Tamajima Bay, Okayama prefecture

1995

• JIS A 6206 “Ground granulated blast-furnace slag for use in concrete” instituted

• Ground granulated blast- furnace slag incorporated into JIS standards dealing with concrete products (JIS A 5327 “Manhole rubble for sewerage,” JIS A 5345 “Ferroconcrete gutters for roads”)

• AIJ drafts draft policy on design and execution of concrete mixtures using ground granulated blast- furnace slag, presents lecture on same

• Experimental work conducted with steel slag as steel-plate hearting material in Yokkaichi Bay temporary shore protection work (joint research with Transport Ministry 5th Ports & Harbors Construction Bureau and CDIT)

• Studies initiated towards JIS standardization of EAF oxidizing slag concrete aggregate

• New Soil Improvement Material Study Group launched in Chubu area with focus on EAF reducing slag

• Over one million tons of granulated blast-furnace slag used in recovery work after Great Hanshin-Awaji Earthquake

• Slag News resumes publishing

• 27 ordinary-steel EAF operators provide data for NSA steel slag market statistics (near 100% coverage)

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• Certification of BOF upper-lay roadbed material by Osaka prefecture

1996

• Deliberation on revision of JIS A 6206 “Ground granulated blast-furnace slag for use in concrete” (compliance with ISO method for mortar test methods, other)

• JSCE revises execution policy for concrete using ground granulated blast- furnace slag, presents lecture on same

• Experimental work performed with steel slag SCP technology in shore protection works at Kobe Rokko Island.

• Special Committee on EAF Slag formed within Technical Committee

• Preparatory Committee for EAF Oxidizing Slag Use Research inaugurated

• Ferrous slag expansion stability test methods and NSA rapid simple test methods unified

• Study group with Kanto Regional Construction Bureau inaugurated with view to promoting use of ferrous slag in road-building

• English version drafted of “Properties and Utility of Steel Slag” pamphlet

• Granulated slag exports exceed one million tons

• JISF formulates Voluntary Action Plan on Environmental Safeguards in the Steel Industry

1997

• JIS A 6206 “Ground granulated blast-furnace slag for use in concrete” revised

• Common construction industry specifications revised (ground granulated blast-furnace concrete incorporated as additive for mass concrete

• Sub grade granulated slag testing equipment operated, certified by Chiba prefecture

• JIS A 5011 “Slag aggregate for concrete” revised (made JIS A 5011-1 “Blast- furnace slag aggregate”

• Experimental offshore SCP work performed with steel slag in Dejima district of Hiroshima Bay

• In-situ marine testing heads for suspension in steel slag application research to water and bottom-sediment purification (use as sand- cover material)

• Steel slag roadbed material certified by Osaka city

• JISF conducts production testing of wave- suppressor blocks using EAF oxidizing slag (research contracted by Clean Japan Center)

• Assisted with formulation of Environment Agency’s recycling guidelines

• Environmental Technologies Working Group formed within Technology Committee

• Study group dispatched to study current ferrous slag recycling practices in Europe (seeking international coordination on environmental issues)

1998

• Feasibility studies initiated on application of granulated slag as SCP material for port and

• Exploration of steel slag handbook for harbor and port construction work use

• New Soil Improvement

• JISF Research Group for the Expanded Use of Ferrous Slag inaugurated

• Activities initiated for

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harbor construction works • JIS A 5308 “Ready-mixed

concrete” revisions announced (ground granulated blast-furnace slag incorporated as additive)

• Zennama (national confederation of ready-mixed concrete businesses) drafts “Production Manual for Concrete Using Ground Granulated Blast-Furnace Slag” (collaboration by ready-mixed concrete, cement and slag industries)

Material Study Group report drafted (EAF reducing slag)

accepting orders for Chubu International Airport

• Full-fledged use of steel slag in offshore SCP work in Hiroshima prefecture, 1.20 million tons delivered


1999

• EAF Oxidizing Slag Utilization Research Committee inaugurated

• Portland Blast-Furnace Slag Cement Promotional Working Group inaugurated

• Exploration of slag use begins in Phase II of Kansai Airport project and New Kitakyushu Airport and Kobe Airport projects

2000

• Sub grade replacement method using granulated slag for civil engineering registered with MLIT NETIS (New Technology Information System)

• Development of bottom- sediment improvement material using granulated blast-furnace slag: Participation in experimental Marino-Forum 21 project (Lake Shinji environmental remediation research)

• Expanded availability of granulated slag for civil engineering: Experimental

• “Steel Slag Handbook for Port and Harbor Construction Work” issued by CDIT & NSA

• Law Concerning the Promotion of Procurement of Eco-friendly Goods and Services by the State and other Entities (Law on Promoting Green Purchasing) promulgated

• Basic Law for Establishing a Recycling-Based Society promulgated

• Law for Promotion of Effective Utilities of Resources (revision of Law for the Promotion of Utilization of Recycled Resources) instituted, designating the steel industry a qualified resource-saving industry

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granulated slag SCP work in Hakata Island City landfill project (joint research with CDIT), evaluations of granulated backfill material performed in Yokosuka Bay Kurihama district

(slag byproducts) • Granulated slag employed

as sand matting material at Kitakyushu Airport

• NSA website goes live

2001

• Ministry of Construction building work specifications revised, standardizing Portland blast-furnace slag cement for cast-in-place piles

• AIJ issues revised policies on Portland blast-furnace slag cement and ground granulated blast-furnace slag

• Participation in experimental Marino-Forum 21 project (Lake Shinji environmental remediation research), empirical testing of sand-cover conducted at Kyobashikawa in Matsue city

• JIS drafting committee inaugurated for EAF oxidizing slag

• Portland blast-furnace slag cement listed as eligible for “green procurements” in Law on Promoting Green Purchasing

• “Fluorine soil environmental quality standards Q&A” and “About the environmental quality standards” drafted

• 2001 Industrial Waste Preventive Measures (eluent evaluation standards formulated for use of ferrous slag material)

• Steel Industry Foundation for the Advancement of Environmental Protection Technology (SEPT) compiles “Research Directions in High-Value-Added Creation and Productization of Ferrous Slag and on Future Research Challenges” and “Selected Essays on Ferrous Slag”

2002

• MLIT Tohoku Regional Bureau adopts Portland blast-furnace slag cement for civil engineering works

• Portland blast-furnace slag cement acquires special approval in Law for Assurance of Residential Quality

• JSCE issues “Design and execution guidelines for use in concrete of EAF oxidizing slag aggregate”

• Ferrous slag-mixed roadbed material, ferrous slag-mixed asphalt admixture, rock wool and blast-furnace slag aggregate made eligible for Green Purchasing Law procurements

• Slag use in Chubu

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• “Use of Portland Blast-Furnace Slag Cement for Cement” PR pamphlet issued, revised version issued annually thereafter

International Airport construction

• Slag use terminates in New Kitakyushu Airport Phase I & II construction

• “Slag Glossary” posted on website

2003

• MAFF employs Portland blast-furnace slag cement for civil engineering works

• Slag aggregate for concrete: JIS revisions blast- furnace slag

• Quality control manual drafted for EAF oxidizing slag aggregate

• Slag aggregate for concrete: JIS standard instituted for EAF oxidizing slag

• Granulated slag for civil engineering eligible for Green Purchasing Law procurements

• Progress towards slag use in construction of New Kitakyushu Airport

• Chubu International Airport opens (1.90 million tons of ferrous slag used)

• Cumulative steel slag deliveries of four million tons for offshore SCP projects in Hiroshima prefecture

2004

• Revision of criteria for EcoMark approval make Portland blast-furnace slag cement, ground granulated blast-furnace slag and ferrous slag for road-building eligible

• Testing begins of granulated slag sand-cover material at Lake Shinji

• EAF Slag Promotion Committee inaugurated

• First JIS-certified plant for EAF oxidizing slag aggregate

• Steel slag for ground improvement made eligible for Green Purchasing Law procurements

• MLIT Ports and Harbors Bureau issues “Policy on recycling technologies in port, harbor and airport infrastructure”

• Promotion of ferrous slag usage in Kobe Airport construction (1.60 million tons)

• Slag product adopted for Phase II of Kansai Airport construction

• Website pages for beginners posted

Slag Itroduction

Documents

Transcript of Slag Itroduction