1. Sustainable Use of Steel Slag in North America
Workshop:
Sustainability of Brazilian Steel Sector
Steel Slag – From Generation in Steelworks to Environmentally Sustainable Utilization

2. Agenda Sustainable plan for steel slag in Canada
Agricultural liming standard & certification
Risk assessment from US steel slag coalition
Properties and sustainable uses of SS in US
Phosphorus removal
Conclusion

3. Environmental Authority in Quebec, Canada
Ministry of Sustainable Development, Environment & Park
Adopt the Rio declaration from 1992 UN conference in Rio
Urgency of reconciling economic and social development
Environmental protection
Conservation of natural resources

4. Residual material in Quebec
Non-hazardous material generated in Quebec = 20 Tonnes per minutes.
Quebec Residual Materials Management Policy has goal to reclaim 65% of them by year 2008.
For helping, use of laws, regulations, guidelines, R&D, directives, fact sheets, guides and standards.
For steel slag tool was:
R&D :Bioavailability Evaluation of Heavy Metal Inbound in Industrial Inorganic Residual Materials
Guide to reclaim Industrial Residual Material, non-hazardous and inorganic as construction material

5. Evaluation of the material
Description of the process generating
Representative sampling
Checking if it is non-hazardous
Gradation (Sieve analysis)
Physical properties
Organic matter
Capability to neutralize the acid
Sulfur contents = acidic generator
Total component
Leaching tests, neutral and acid

6. Reclaim Agreement for Steel Slag
Agreement between Minister of Environment and the steel Mill which generate the steel slag (SS)
Minister facilitate and encourage such value added while ensuring that it is done in a manner that does not harm the quality of the environment
SS is not consider soil in the meaning of Soil Protection and Sites Rehabilitation Policy
The use of SS is associated with structures and not mingling with soils
Contract to set out the terms and conditions governing the interventions, actions, and activities with respect to the recycling

7. Obligation for marketing Steel Slag
Inform purchaser of the potential uses and restriction
Proceed periodically to the analysis of SS
Present a report specifies the quantity of SS received and the quantity processed and for each category of aggregate, specifies the quantities marketed, stored or disposed
Invest part of the benefit from SS sales for R&D
Produce & distribute a brochure (approved) intended to
Inform customers of the nature of SS
Promote the use of SS for authorized uses
Subsequent to a dismantling of the work at the end of its useful life, reuse possible (same as permit)

8. Decision-making diagram for aggregate categorization

9. Usage authorized according to category
Category of materials I II
III IV V
1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors)
Sub-base x
Base – paved roads
Paved road shoulder
Base – unpaved roads
Unpaved road shoulder
Backfill
Mineral filler
Manufactured sand
Surface treatment
Hot and cold mix asphalt
Aggregate for slurry seal
Filling concrete

10. Usage authorized according to category
Category of materials I II
III IV V
2.Winter anti-skid for roads x
3.Residential driveway for automobile
4.Other residential uses
5.Construction on municipal land
6.Construction on commercial or industrial land
7.Coating for landfill sites
8.Sandblast aggregate
9.Railroad Ballast
The reuse of SS dismantled from a structure shall be done in accordance with those one

11. Slag sales scale ticket
Usage permitted

12. Slag uses

13. Slag uses

14. Slag uses

15. Slag uses

16. Slag uses

17. Liming material for agricultural use
BNQ is a standards development body accredited by the Standards Council of Canada (SCC)
Authorized to develop consensual normative documents (Standards) up to the national level and to participate into regional and international standardization activities
In 1998, a committee of 20 persons from different industries and government agencies elaborate the specification: #NQ /1998 Liming Materials from Industrial Processes
The certification to have recognized, on an ongoing basis, the conformity of ladle furnace slag according to this specification
Certification bring : authenticity, safety of the product and technical info

18. Requirement for certification
BNQ 2 visits and sampling per year
Production and sales report to submit
Size 100% < 14mm
Size 95% < 12,5mm
Water content > 1% (CaO)
Neutralizing value (CCE) > 25% (our value 85%)
Causticity (Ca+Mg)/(Na+K) > 2,5
Marking of the product should be on the scale ticket
Efficiency is obtained by comparing the effect of pH increase with pure ACS grade CaCO3
Metal content depend of CCE

19. Metal limit in lime material
Metal (ppm)
Dry basis
CCE
25%
50%
75%
100% As 37 75 Cd 10 20 30 Co
150
225
300 Cr
530
1 060
1 590
2 120 Cu
378
757
1 135
1 500 Hg
2,5
5,0
7,5 Mn
6 250
12 500
18 750
25 000 Mo 40 Ni 90
180
270
360 Pb
250
500 Se
7,0 14 21 28 Zn
926
1 850
2 778
2800

20. US Geological Survey-2005
Ferrous slags are valuable co-products of ironmaking and steelmaking.
In 2005 about 21 million tons of domestic iron and steel slag, valued at about $326 million (f.o.b.) was consumed.
There were 29 slag-processing companies servicing iron and/or steel companies or reprocessing old slag piles at about 130 locations: iron slag at about 40 sites in 14 States and steel slag at about 90 sites in 32 States.

21. Risk assessment from US Slag Coalition
In 1998, group of 63 US Steel producers and/or Slag processor companies commissioned ChemRisk for:
Comprehensive study of chemical composition of 3 slag types; BF, BOF, EAF : potential human health & ecological risk associated with possible exposure to such slag
Study utilized worse-case exposure assumptions in risk calculations
Conclusion:
“Slag pose no meaningful threat to human health or the environment when used in a variety of residential, agricultural, industrial and construction applications”
Steelmaking slag: A safe and valuable product

22. Steelmaking slag composition
Chemically, steelmaking slag is a complex matrix structure consisting primarily of oxides of calcium, iron, silicates, aluminum, magnesium, and manganese in complexes of calcium silicates, aluminosilicates and aluminoferite.
These compounds are similar to those found in the natural environment.
Typical furnace temperatures of about 1600oC fuses the oxidized components captured in slag.
The matrix tightly binds metals found in slag and they are not readily liberated from the particles. Metals in slag are not easily leached.
Matrix

23. Physical properties Cubical, vesicular surface
Excellent frictional properties
High stability
Interlocking
High angle of repose

24. Major uses of steelmaking slag aggregates
Bituminous applications: pavement surfaces, surface treatments, asphalt, seal coats, slurry coats and cold patch
Concrete aggregate
Raw feed for Portland Cement manufacturing
Anti-skid (snow and ice control)
Stabilization: shoulders, banks, erosion control, gabions and riprap
Base and sub-base
Unpaved driveways, surface roads, walkways, trails
Neutralization: acid mine drainage
Agricultural applications: soil remineralization, liming agent, fertilizer
Controlled granular fill, structural fill, pipe and tank backfill, berms
Fluxing agent for steel mills
Landfill cover material
Landscaping
Trench / drain fields
Sand blast grit
Roofing granules
Bulk filler (paint, plastics, adhesives)
Soil stabilization
Mineral wool
All purpose construction aggregate

25. Risk Assessment Process
To quantify potential threats to human health or the environment
Three phases
Dose-response assessment
Exposure assessment
Risk characterization
Results demonstrated BF, BOF and EAF slags are safe for use in a broad variety of applications and pose no significant risks to human health or the environment

26. Risk Assessment Conclusion
BF, BOF and EAF slags are a safe sustainable material
Steelmaking slag is an environmentally safe product
Unique physical structure out-performs natural aggregates
Superior construction, industrial and agricultural aggregate
A safe, useful and valuable product – not a “solid waste”
Emphasis on State and Federal regulatory systems in recognition of the value of steelmaking slag as a product
Conserves natural resources

27. Sustainable Utilization of Steel Slag in the US
Bituminous Applications
Stone matrix asphalt
Superpave
Asphalt
Chip and Seal
Slurry Seal
Cold patch
Advantages:
frictional properties
hardness
soundness
angularity

28. Indianapolis Speedway

29. Sustainable Utilization of Steel Slag in the US
Slag as raw feed in Portland Cement
Reduction in CO2 emissions and energy cost
Slag has already undergone calcination (clinker)
Melts at a lower temperature
Improved clinker production
100% yield of cement clinker vs. limestone as low as 60%
Chemically compatible
CaO
SiO2
Al2O3
Fe2O3
Reduce or replace:
Iron ore
Mill scale
Bauxite
Clay
Sand
Fly ash
Shale
Methods of introduction:
Inter-ground in existing raw mill
Feed directly into the back end of the kiln (a patented process in the US)

30. Feed into the back end of kiln

31. Sustainable Utilization of Steel Slag in the US
Base Applications
Unpaved surfaces
Roads and road shoulders
Access roads for heavy equipment
Parking lots and lay-down yards
Driveways
Pathways / walkways
Equestrian rings / trails
Berms
Embankments
Advantages:
Durability
Compaction
Cementitious properties

32. Unpaved Applications in Arkansas, Mississippi and Utah

33. Sustainable Utilization of Steel Slag in the US
Stabilization
Bank stabilization
Erosion control
High angle of repose
Durability
Gabions and riprap
Dikes and barriers
Soil stabilization
Current research being performed by the School of Civil Engineering, Purdue University– joint cost sharing between MultiServ and Levy as industry, and the Indiana Department of Transportation

34. Oyster beds in Maryland (2), Wildlife Bird Refuse in Utah and Soil Stabilization in Michigan

35. Gabion basket with steel slag
Rectangular wire mesh basket filled with coarse size (50 to 100mm) Steel Slag
To shore up creek bank and control water flow
Angular shape and high density provide stability
Protection against erosion

36. Sustainable Utilization of Steel Slag in the US
Other Applications
Rail ballast
Anti-skid for snow and ice control
Dark color – absorbs heat from the sun
Stays in place
Landscape rock
Daily Landfill cover
Aggregate for septic systems
Acid mine drainage
Agricultural soil re-mineralization, liming agent, fertilizer

37. Ag-lime in North Carolina

38. Acid mine drainage treatment
SS generate exceptionally high levels of alkalinity over extended periods (several hundred times more than limestone)
SS has a high neutralization potential
Design and sizing can provide a low-to-zero maintenance
No leaching even in acidic condition

39. Requirements vary by State
State regulations
EPA regulations
Test Methods for materials
ASTM
AASHTO
Environmental testing
TCLP
Total metals
Chemical analysis
General testing
Sieve analysis (gradation)
Specific gravity
Absorption
Unit weight
Moisture density (proctor)
LA abrasion
Soundness
Calcium carbonate Equivalent (CCE) for agricultural applications

40. Analytical Test Methods
U.S. Environmental Protection (EPA) approved test methods
Total metals
Toxicity Characteristic Leachate Potential (TCLP)
pH parameters
American Society of Testing Materials (ASTM) distilled water leachate tests for certain metals
Bioaccessibility of certain metals
Particle size distribution

41. Comparisons
TCLP and ASTM leaching tests to determine if any metals in slag would potentially affect groundwater and surface water.
Results compared to appropriate TCLP drinking water quality standards and EPA Ambient Water Quality Criteria.

42. EAF Slag for phosphorus removal
Phosphorus = Phosphate (P), a nutrient that may cause lake eutrophication and toxic blue green algae
Tests on dairy farm waste water and fish farm
Conclusion proved that phosphorus filter with EAF significantly reduced dissolve reactive P (DRP)
Removed over 70% of DRP during the first 269 days
Need to use wetland pre-treatment to remove suspended solid and prevent clogging
EAF can be reuse after treatment as aggregate for farm road.

43. Phosphorus retention mechanism
Steel slag

44. University of Waterloo research
BOF Slag: sorption and co-precipitation removal of phosphate and arsenic and selenium
Excellent removal of arsenic to very low levels
Effective removal of E-Coli
Elevated pH provides environment that eliminates bacteria
Elevated pH is buffered by soils and sediments upon release to subsurface

45. Phosphate removal with BOF
North Bay System: Phosphate Versus Time
Days of Operation
200
400
600
800
1000
1200
1400
1600
Phosphate-P (mg/L) 5 10 15 20
Raw Phosphate
Sand Filter Phosphate
BOF Chamber Phosphate
From: David Smyth Department of earth sciences, University of Waterloo, Waterloo, Canada

46. Batch Removal Rates with BOF
As(III) + As(V)
Se(VI)
1000
1000
800
800
As total (mg/L)
600
600
Se(VI) (mg/L)
400
400
200
200 2 4 6 8 2 4 6 8
Time (h)
Time (h)
Time (h)
Time (h)
From: David Smyth Department of earth sciences, University of Waterloo, Waterloo, Canada

47. Montreal Biodome research project
Closed marine system 3000 m3 (large marine aquarium)
Home to about 100 seabirds, 600 fishes, 2000 invertebrates from gulf of St-Lawrence
Contained 20 mg P/L (60 kg P)
Pilot unit of 9.5T remove 7 kg P (0.75 g P/kg slag) lasted 93 days, the flow rate = 3 to 9 L/min
During test some animals breed, that showed the good quality of the water
Efficiency limited by the formation of a bacterial biofilm

48. Conclusion Reputation Co-product
Quality control of this resource is important
Slag processor = aggregate processor
SS has more advantage than disadvantage
Sustainability = conservation of natural resource