Restart of BF#2 Using Durfee Method

Salient Features o Inner volume: 3,814 m3 o Working volume: 3,230 m3 o Number of tuyeres: 34 o Charging system: with belt conveyor and Paul Wurth Parallel hopper Bell Less Top®, o Cooling system o Under-hearth: water pipes o Hearth: cast-iron staves o Tuyere belt: cast iron staves o Bosh to lower Stack: copper staves o Middle Stack to Throat: cast iron staves o PCI design for 200 kg/thm o Top Gas Recovery Turbine 14 MW

Chilled Hearth Condition Start Up Situation Hot Metal and Slag Solidified Chilled Hearth Condition Unprepared Shut down for 162 days

Major tasks of Recovery Process Re-instate connection between Tap hole and Tuyeres Recover the Thermal Status Melting of Solidified Metal and Slag Stabilize the Process

Process discussed for Revival Durfee Process Blowing Hot Blast through Tap hole enriched with Oxygen Normally Used for Prepared shut downs Less aggressive on Refractory Oxy-Fuel Process Installing Oxy-fuel burners through Tap holes equipped with external fuel + Oxygen Can be used for severe chilled recoveries

Process Selected for Revival Durfee Process Reasons Furnace had coke O/C ratio 2.1 Extra Coke of around 90 T available in Lower Stack

Durfee Process

Time Line of Start Up Day-2 Day-3 Day-4 Day-5 Blast Introduced through Durfee No Blast flow observed Durfee removed and Tap Hole Lanced for 20 Hrs Day-2 Durfee Re-Introduced Blast Flow Average 7200m3/hr Blast Enriched with Oxygen Day-3 Cumulative Flow through Durfee ~ 140000 Nm3 4 Tuyere Opened above Tap Hole No 2 Durfee removed and First slag cast through Tap Hole No 2 Day-4 Hot Metal and Slag in Dry Pit Day-5 Hot Metal taken in Torpedo Ladle GCP Connected

Tuyere Opening & Blast Volume Increase

Sequence of Tuyere Opening

Hot Metal Production Tons Per Day