Steelmaking at ArcelorMittal Dofasco

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Steelmaking at ArcelorMittal Dofasco
Group 1 Andrew, Fran, Matt, Megan, Mikaela
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ArcelorMittal Dofasco

• Started out as Dominion Foundries and Steel in
  1912 making 80 tons of steel castings
• Produce over 4 million tons of high quality flat
  rolled steel
• Introduced innovative profit sharing program in
  1938
• Became fully integrated mill in 1951
• In 2006, was acquired by world giant Arcelor, who
  later merged with Mittal, forming ArcelorMittal
  Dofasco
• Awarded sustainability and Top Employer Awards

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Dofasco Products

• Products include galvanized steel, tin plate and
  tubular products for the automotive, construction
  and packaging sectors

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Primary Services

• Dofasco divided into 2 main areas
• Primary
• Finishing
• Primary area consists of
• Raw Materials Handling
• Cokemaking
• Ironmaking
• Steel making
• KOBM
• EAF
• Continuous Casting

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Dofasco Primary Flow Sheet
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KOBM Basic Oxygen Steelmaking

• KOBM Technical Information
• 300 tonne Basic Oxygen Converter
• 70 Hot Metal 30 Scrap Charge
• O2 Input- 70 Top Lance 30 Bottom Tuyeres
• Lime Dolime Bottom Injection
• Alloy/Flux Handling System

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Steelmaking in the KOBM

• Typically consists of 6 steps
• Charging of Scrap Metal
• Charging of Hot Metal
• Blowing of Oxygen
• Sampling
• Tapping of Steel
• Slag off

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Steelmaking in the KOBM
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Blowing

• KOBM unique because oxygen blown into molten iron
  through both
• the top of the furnace (by a main lance)
• the bottom of the furnace (by tuyeres)
• Oxygen used to selectively oxidize C, Si, P, Mg

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Tapping Slag Off

• Once adequate concentration of carbon in bath,
  tilt furnace to get molten steel out
• Molten steel melts plug, flows into ladle
• Ladle moves onto Ladle Metallurgy and Vacuum
  Degassing

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Specific Steelmaking Process Principles

• Model Carbon content to improve times and
  increase efficiency
• End Point Determination Reaction
• 2CO O2 ? CO2

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Specific Steelmaking Process Principles

• Batch Process potential problem of unmelted
  Scrap

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Economics Operating Costs

• Annual Production Rate 2.4 million tons
• Average cost per ton (crude steel) 353.50
  (highly variant with input costs)

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Iron Ore Iron Ore Transport Coking Coal Coking
Coal Transport Steel Scrap Oxygen Refractories
Electricity Labour
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Operating Variables

• Many variables can contribute to operability and
  flexibility, including

• Amount of scrap or hot metal charged
• Temperature of hot metal being charged
• Temperature of furnace (the bath itself)
• Composition of the bath

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Operability Operating Window

• Critical parameters for our operating window are
  C and Blowing Time (essentially amount of
  oxygen)

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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

1. Pit under furnace capable of holding 100 of
contents
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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

2. Laser and Thermal Imaging of Refractory
Materials
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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

3. Red stripe on Hard Hat for New Workers
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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

4. If there is a loss of furnace cooling water,
O2 blow turns off.
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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

5. Dofascos Onsite Fire/Security/Medical
Personnel.
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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

6. If there is a loss of power, the furnace will
immediately tap or tilt to prevent tuyere damage
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Safety

• 6 Levels of Safety
• Process Control
• Alarms
• SIS
• Safety Relief
• Containment
• Emergency Response

7. Extended diagnostics must be successful to
begin blowing procedure.
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Troubleshooting
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Troubleshooting
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Wrap-up

• The Future of Steelmaking

• Unique Process Specifications Issues

• Environmental Concerns

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FUTURE OF STEELMAKING AT DOFASCO
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Refractory Lifetime

• Costs 1,000,000 in materials alone to replace
  refractory lining
• Try to reuse slag as lining
• Downtime in furnace production more substantial-
  already use slag as for protection

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Improved Models

• Models for C in bath based on CO and CO2 models
  (multi-variant statistical control)

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Steelmaking Energy Issues

• To save money, reuse gases as fuel in steelmaking
• Ratio of Coke Oven Gas (COG) and Blast Furnace
  Gas (BFG)
• Hope for Co-Generation Facility

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UNIQUE PROCESS SPECIFICATIONS AT DOFASCO
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Steelmaking Input Issues

• Raw materials are shipped to Dofasco
• Harbor freezes in the winter
• Stockpile during shipping season

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Steelmaking Output Issues

• Steelmaking business unit consists of only BOF
  furnace and EAF furnace
• More downstream processing than upstream
  processing- must import

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Steelmaking Scrap Issues

• Scrap metal varies in quality- important to
  evaluate quality to ensure safety

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Steelmaking Shipping Issues

• Steel used for high-end applications
• Sensitive to moisture and contaminants- need
  climate controlled environment

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ENVIRONMENT AT DOFASCO
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Steelmaking Problems

• Steelmaking a dirty business
• New environmental regulations require stricter
  control for Point of Impingement- Dofasco has
  asked for an extension
• Dofasco policy always leading the group for
  Canadian steelmakers
• ISO 14001 Certified

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Unique Issues at Dofasco

• Right next to the harbor
• Required for the process
• On reclaimed land
• Extremely careful about effluent and wildlife

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Unique Issues at Dofasco

• Try to discourage birds from nesting, so borrow
  wildlife and tether them near water to discourage
  birds

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Unique Issues at Dofasco

• Very conscious groups in Hamilton for air
  emissions
• Have 1 guy to watch for emissions 24 hours a day
• Steelmaking uses bag house to minimize emissions

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Acknowledgements

• Thanks to people at Dofasco ArcelorMittal who
  provided information on the process and the site
  
• Rick Finlay
• Joseph Lasowski

Questions?