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Sustainable Use of Steel Slag in North America

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Steel Slag From Generation in Steelworks to Environmentally Sustainable ... Oyster beds in Maryland (2), Wildlife Bird Refuse in Utah and Soil Stabilization ... – PowerPoint PPT presentation

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Title: Sustainable Use of Steel Slag in North America


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
    1998-2008 has goal to reclaim 65 of them by year
    2008.
  • For helping, use of laws, regulations,
    guidelines, RD, directives, fact sheets, guides
    and standards.
  • For steel slag tool was
  • RD 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 RD
  • 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
Usage Category of materials Category of materials Category of materials Category of materials Category of materials
Usage I II III IV V
1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors) 1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors) 1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors) 1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors) 1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors) 1. Construction or repair of roadways, roads and streets (including those in residential, municipal and agricultural sectors)
Sub-base x x x x
Base paved roads x x x x
Paved road shoulder x x x x
Base unpaved roads x x x
Unpaved road shoulder x x x
Backfill x x x x
Mineral filler x x x x
Manufactured sand x x x x
Surface treatment x x x x x
Hot and cold mix asphalt x x x x x
Aggregate for slurry seal x x x x x
Filling concrete x x x x x
10
Usage authorized according to category
Usage Category of materials Category of materials Category of materials Category of materials Category of materials
Usage I II III IV V
2.Winter anti-skid for roads x
3.Residential driveway for automobile x x
4.Other residential uses x
5.Construction on municipal land x x x
6.Construction on commercial or industrial land x x x x
7.Coating for landfill sites x x x x x
8.Sandblast aggregate x x x x x
9.Railroad Ballast x x x
  • 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 0419-910/1998 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 lt 14mm
  • Size 95 lt 12,5mm
  • Water content gt 1 (CaO)
  • Neutralizing value (CCE) gt 25 (our value 85)
  • Causticity (CaMg)/(NaK) gt 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 CCE 50 CCE 75 CCE 100
As 37 75 75 75
Cd 10 20 30 30
Co 75 150 225 300
Cr 530 1 060 1 590 2 120
Cu 378 757 1 135 1 500
Hg 2,5 5,0 7,5 10
Mn 6 250 12 500 18 750 25 000
Mo 10 20 30 40
Ni 90 180 270 360
Pb 250 500 500 500
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

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

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
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
600
600
As total (mg/L)
Se(VI) (mg/L)
400
400
200
200
0
0
0
2
4
6
8
0
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
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