Transcript General MultiServ Presentation Template

Sustainable Use of Steel Slag
in North America
Workshop:
Sustainability of Brazilian Steel Sector
Steel Slag – From Generation in Steelworks to
Environmentally Sustainable Utilization
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
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
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, 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, nonhazardous and inorganic as construction material
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
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
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)
Decision-making diagram for aggregate
categorization
Usage authorized according to category
Usage
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
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
Manufactured sand
Surface treatment
Hot and cold mix asphalt
Aggregate for slurry seal
Filling concrete
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Usage authorized according to category
Usage
Category of materials
I
II
III
IV
V
2.Winter anti-skid for roads
x
3.Residential driveway for automobile
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
x
The reuse of SS dismantled from a structure shall be done in accordance with those one
Slag sales scale ticket
Usage permitted
Slag uses
Slag uses
Slag uses
Slag uses
Slag uses
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
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
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
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.
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
Steelmaking slag composition
Chemically, steelmaking slag is a complex
matrix
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.
Physical properties
Cubical, vesicular surface
Excellent frictional properties
High stability
Interlocking
High angle of repose
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
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
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
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
Indianapolis Speedway
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)
Feed into the back end of kiln
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
Unpaved Applications in
Arkansas, Mississippi and Utah
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
Oyster beds in Maryland (2), Wildlife Bird
Refuse in Utah and Soil Stabilization in
Michigan
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
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
Ag-lime in North Carolina
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
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
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
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.
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.
Phosphorus retention mechanism
CO2atm
KH2PO4
K+
KH2PO4
H+
K+
H2PO4-
H2PO4H+
Adsorption
H+
H+
HPO42-
H+
HPO42-
CaCO3
PO4
HDP
Strengite
Ca
OH
Al
Variscite
PO4
H2O
OH
Précipitation
(cristallisation)
PO43-
PO43HAP
HPO4
Phase aqueuse
H+
OH
Fe
H2O
Ca2+
CaO
H+
OH-
H+
OH-
Dissolution
Scories
Steel slag
H2O
Fe3+
Fe2+
FeO
H2O
OH-
Al3+
H2O
Al2O3
NB: Précipités formés:
HDP = Ca2 HPO4 (OH)2
HAP = Ca10 (PO4 )6 (OH)2
Strengite = FePO4 .2H2 O
Variscite = AlPO4 .2H2 O
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
Phosphate-P (mg/L)
Phosphate removal with BOF
North Bay System: Phosphate Versus Time
20
Raw Phosphate
Sand Filter Phosphate
BOF Chamber Phosphate
15
10
5
0
0
200
400
60
800 1000 1200 1400 1600
Days
of Operation
0
From: David Smyth Department of earth sciences, University of Waterloo, Waterloo, Canada
Batch Removal Rates with BOF
Se(VI)
1000
1000
800
800
Se(VI) (mg/L)
As total (mg/L)
As(III) + As(V)
600
400
200
600
400
200
0
0
0
2
4
Time
(h)(h)
Time
6
8
0
2
4
Time
(h)(h)
Time
From: David Smyth Department of earth sciences, University of Waterloo, Waterloo, Canada
6
8
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
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