GLOBAL SLAG Slags and road construction

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GLOBAL SLAG Slags and road construction

• 10 NOVEMBER 2008

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Summary

• Slags and road construction
• Electric Arc Furnace slag
• The origin of EAF slag
• Quantity and quality of EAF slag
• More important use for EAF slag
• BOF slags treatment new opportunities for slags
  case of LD gravel
• Conclusions

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EAF steelmaking in ArcelorMittal worldPotential
of recycling

• The plants of ArcelorMittal produce each year
  3.900.000 tons of EAF slag which are
• Stored internal,
• Stored on external landfill,
• Recycled in road,
• Used for internal road or internal development.

Regular production and quantities stored could be
used in the road construction all other the world
in the area of each plant
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Steelmaking in an electric arc furnace
Electric arc furnace and ladle furnace
Scrap Yard
Continous Casting and ladle metallurgy
Beam blank
Rolling Mill
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Generation of electric arc furnace slag / Black
slag

• In the EAF, the slag is used to protect the
  furnace walls for not being damaged by the
  electric arc during the metallurgical refining of
  the steel
• The liquid foamy slag allows to fix the metal
  oxides (SiO2 / Al2O3 / MnO / MgO / P2O5) produced
  during the scrap melting and steel refining
  process
• The slag plays an essential role in the heat
  transfer from the electric arc to the bath of
  steel

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Where is produced the slag in the process of
electric arc furnace ?
Scraps
Dedusting pipes
Iron pot
Slag pot
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The furnace
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Quantity and quality of EAF slag
Lime and dolomite are added during the fusion
process of the scrap in the EAF Quantity produced
80-120 kg/t General composition of the slag at
the end of the steel refining process
CaO 20-30 SiO2 10-20 MgO 2-6
MnO 6-8 Al2O3 6-9 Fe 20-35
ADVANTAGE Free lime lt1 At the end of the
heat, the slag is tapped in a slag pot and
evacuated explained as followed.
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Management of liquid EAF slagExtraction from the
EAF
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Management of liquid EAF slagRefresh and crushing
EAF slag preparation for road construction
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Management of the electric arc furnace
management of the quality of slag
Quality of the slag directly linked to the
homogeneity of the temperature in the furnace
- minimal temperature needed to obtain liquid
iron ? fluidity of the liquid slag with no
formation of big block no fresh area in the
furnace ? increase the protection of the
furnace ? less scraps in the slag Quality of
the slag directly linked to the refreshment of
the slag - a slow cooling will guarantee a good
crystallization of the product
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Chemical survey asked for the recycling

• Depending on the country different analysis are
  asked by the local government
• In order to check if your EAF slag can be used
  for road making the following analysis are
  usefull chemical analysis
• on the slag samples / on the leaching water
• mg/kg pH
• Fe tot Zn Conductivity µS/cm
• CaO Pb Metals mg/l
• SiO2 Cd Zn
• MgO Ni Pb
• Al2O3 As Cd
• MnO V Ni
• P2O5 Cu As
• Cr-tot V
• S Cu
• CaO free Cr TOC
• Phenol
• AOX
• CN free
• Results of leaching tests compared to the limit
  applied on ground water used for drinking water
  production. NEVER HAD ANY HIGH VALUE

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Physical and mechanical propertiesParameters for
road construction

• The local authorities and customers will ask for
  several quality criteria concerning
• Grading structure of the product
• Particle shape
• Density Particle density, water absorption
• Porosity
• Cleanness fines content
• Resistance to the compression (CT 1/75/80)
• Resistance to polish (polished stone value)
  (CPA)
• Resistance to fragmentation (Los Angeles)
• Resistance to wear (MicroDeval)
• Durability against freeze-thaw
• Stability
• Affinity with bitumen
• These parameters will be found in the agreements
  from concerned authorities.

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Real test Construction of a little part of
road

• All the lands where EAF slag is recycled today
  need to show to their authorities that roads made
  with EAF slag
• ? didnt react with the environment,
• didnt get new fissures after few months,
• didnt swell due to the water reacting with free
  lime not detected by the analysis,
• This kind of actions is made in order to prove to
  the local authorities that this product will
  react as the natural stones usually used.
• The goal is to obtain all the agreements needed.

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EAF slag a product which will earn to be known
High potential of recycling

• The solidifcation process of the hot EAF slag
  transforms this slag in an artificial stone
• In an economic world where the natural ressources
  are more and more rare, the EAF slag is an
  interesting by-product which can replace the
  natural stones in the road construction.

• This artificial stone has some highly interesting
  physical, chemical and mechanical properties for
  further industrial use.

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Possibles applications for EAF slags

• Grainsizes which could be prepared
• 0/4, 4/8, 8/12,
• Possible applications
• Roads
• Parking
• Concretes
• List of possible products and applications on the
  market
• 1st possibility Aggregates for bituminous
  mixtures and surface treatments for roads,
  airfields and other trafficked areas all-in
  aggregates from electric arc furnace slags 0/4mm
  (Crushed sand 0/4mm)
• 2nd possibility Aggregates for concrete fine
  aggregates from electric arc furnace slags
  (crushed sand) 0/4mm
• 3rd possibility Aggregates for bituminous
  mixtures and surface treatments for roads,
  airfields and other trafficked areas coarse
  aggregates from electric arc furnace slags 4/8 mm

In all applications where actually high quality
natural stones are used, the EAF slag can be put
in place of the natural stone
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GLOBAL SLAG LD Gravel results of an ongoing
project in Gent plant of ArcelorMittal

• 10 NOVEMBER 2008

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AM Gent (SIDMAR)
Production
GENT
2 x BF
Coke plant - Sinter plant
During the transformation from pig iron to steel
10 of BOF-slags are produced, which after
cooling and de-scrapping and after sieving,
several sizes are selected.
2 x LD-TBM 300 t
RH x 1 PM x 3
CC x 2
2 stands slab casters
Slab
Slabs from other UO
Hot coil
HSM
Pickled
Full hard
Annealing B.A. C.A. P.L.
5 stands Coupled with pickl
5 stands Fully continuous
Cold rolled coils from BREMEN
Annealed
SIDGAL 2 / 3
SIDGAL 1
SIKEL (GENK)
2 x CGL
HDG
Galvanized
Galvanized
Electrogalava.
DECOSTEEL I (GEEL)
DECOSTEEL II (GENT)
Organic coat on galvanized
Organic coat
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LD-slags versus LD-gravel

• To ensure the sales market for the future, AM
  Gent decided to transform after tapping the
  LD-slag into LD-gravel.
• The process is made up by blowing oxygen
  together with sand.
• During this treatment the free lime is bound
  with SiO2 to form stable calcium silicates.
• Discussions 2006 with the FLEMISH authorities,
  LD-gravel is a PRODUCT due to new permit
  (European definition not to discard).
• This product is an alternative for natural
  granulates, with a higher specific density 10
  .
• This is an extra trump when used as ballast.
• For road constructions, a higher PSV is another
  extra trump in the top layer of asphalt.

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LD-gravel preparation

• Injection of sand in the slag

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LD-slag versus LD-gravel
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LD-gravel

• Installation exists in Gent in order to prepare
  LD gravel
• The LD gravel obtained has comparable qualities
  as EAF slag
• Today tests have been done in concrete blocks,
  used in road construction and paves

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LD-gravel roads and paves
LD-gravel
Natural Granulate
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LD-Gravel Railway

• Tests to replace porphyry-stones with LD-gravel
  14-22 mm
• Sagging less 3 mm

Porphyry
LD-Gravel
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Conclusions on these two kind of slags EAF slag
and LD gravel

• Actual high costs of natural stones encourages
  the use of slags with a better price,
• Environmental policy of companies can be applied
  by using slags the use of slags by a building
  company will be the result of an environmentaly
  friendly approach, infact
• some slags can be considered as artificial
  stones
• ? reduce the use of natural raw material for
  your projects,
• ? reuse a by-product generated by the human
  activity the lifecycle will be complete with
  this reuse,
• High number of ArcelorMittal plants in the world
  offers an high number of possibilities for
  building companies,
• Price of transport will define the possibilities
  for such applications,

For your next road building projects,
production of blocks of concrete, think about the
slags produced in ArcelorMittal plants all over
the world !