ABSTRACT
The contribution of oxygen to the development and production of steel has been of great importance supporting the ever-increasing production of steel. Prior to the introduction of the basic oxygen furnace (BOF) in the 1950s, nonpurified oxygen (as a constituent of air) played a crucial role in steel refining for Bessemer and open hearth processes. The availability of tonnage oxygen has arguably been one of the biggest factors influencing steel productivity, quality, and development of new steel types. Industrial oxygen is an integral raw material
used in nearly all steelmaking refining reactions in both integrated and minimill process routes including BOF (KOBM, Q-BOP) and electric arc furnace (EAF). Oxygen use has also become necessary for secondary metallurgy processes such as argon oxygen decarburization (AOD, for specialty/stainless steels), vacuum oxygen decarburization (VOD), and other degassing processes such as Ruhrstahl-Heraeus (RH-OB), etc. Steelmakers also exploit oxygen injection for in-ladle refining and reheating during secondary metallurgy processing. In addition to refining, steelmaking facilities have numerous uses of purified oxygen including hand lancing, skull cutting, scarfing (surface blemish removal), and
Nicolas Docquier, Michael Grant, and Kenneth Kaiser
CONTENTS
22.1 Introduction ................................................................................................................................................................... 531 22.2 Electric Arc Furnace ..................................................................................................................................................... 532 22.3 Oxygen in the Electric Arc Furnace ........................................................................................................................... 532 22.4 Summary of Important Steelmaking Reactions ....................................................................................................... 534
22.4.1 Processes That Consume Heat ........................................................................................................................ 534 22.4.2 Processes That Provide Heat ........................................................................................................................... 534 22.4.3 Important EAF Reactions ................................................................................................................................ 534 22.4.4 EAF Mass and Energy Balance ....................................................................................................................... 535 22.4.5 Refining and Lancing ....................................................................................................................................... 536 22.4.6 Refining .............................................................................................................................................................. 536 22.4.7 Lancing ............................................................................................................................................................... 536 22.4.8 Heat Balance of Refining ................................................................................................................................. 538 22.4.9 Charge Carbon Additions ............................................................................................................................... 540
22.5 EAF Burners .................................................................................................................................................................. 542 22.5.1 Burner Position .................................................................................................................................................. 542 22.5.2 Burner Firing Profile......................................................................................................................................... 543 22.5.3 Energy Contribution of Burners ..................................................................................................................... 544
22.6 Postcombustion ............................................................................................................................................................. 546 22.6.1 Description ......................................................................................................................................................... 546 22.6.2 Postcombustion Process ................................................................................................................................... 547 22.6.3 Mass and Energy Balance ................................................................................................................................ 548 22.6.4 Summary of Postcombustion .......................................................................................................................... 549
22.7 Ladle Heating ................................................................................................................................................................ 549 22.7.1 Ladle Heater Overview .................................................................................................................................... 550 22.7.2 Refractory Preheating ...................................................................................................................................... 551 22.7.3 Combustion Considerations ............................................................................................................................ 552
References ................................................................................................................................................................................ 555
torch cutting (both manual and automatic continuous caster torches). Except for electrolytic refining of iron ore (which would produce oxygen as a by-product), it is impossible to imagine any “new” steelmaking process routes which do not extensively rely on the use of oxygen for both refining and auxiliary functions.
