Basic oxygen furnace

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The Basic Oxygen Furnace (BOF), also known as Basic Oxygen Process (BOP), Basic Oxygen Steelmaking (BOM), Linz-Donawitz-steelmaking (LD), or Oxygen Converter Process, uses pig iron from the Blast Furnace (BF) to produce steel. It uses molten pig iron (i.e., hot metal), flux (burnt lime), and sometimes steel scrap as input, oxidation as a process, and has molten steel as its output.

The Process

The raw materials are charged into the converter vessel (i.e., the furnace), where a water-cooled tube (i.e., lance) blows pure oxygen into the mixture for about 20 minutes, causing oxidation of the elements. The oxygen reacts with the carbon and silicon found in the mixture. This creates silicon dioxide, carbon dioxide, heat, and other impurities (e.g., manganese and phosphorus).[1] These impurities are either absorbed by the waste matter (i.e., slag) or released as gas. The oxidation process reduces the carbon level of the steel. Once the desired carbon content is reached, the molten steel and slag are poured off.[2][3] At this point, the steel can be further customized through the addition of different alloys, or be cast into the desired shape, like ingots or slabs.

Structure of a Basic Oxygen Furnace (Source: SubsTech)
Types of Basic Oxygen Furnaces (Source: IspatGuru)

BOFs typically include conventional top-blown furnaces, bottom-blown furnaces, or various mixed-blowing configurations. A top-blown basic oxygen furnace is equipped with a water-cooled oxygen lance for blowing oxygen into the pig iron through 4-6 nozzles. Though less common, a bottom-blown basic oxygen furnace is equipped with 15-20 tuyeres at the bottom of the furnace for injection of oxygen or lime powder containing oxygen. The tuyeres are cooled by either hydrocarbon gas or oil.[4]


Emissions are caused from the gasses expelled into the atmosphere through the process, such as carbon dioxide. Additionally it is the emissions-intensive pig iron, created in Blast Furnaces, that is generally used as input that makes it difficult to reduce emissions using the Basic Oxygen Furnace production route. The production of one tonne of steel via the Blast Furnace-Basic Oxygen Furnace (BF-BOF) route creates approximately 1.8 tons of carbon dioxide, making it the production process with the highest emissions. When including indirect emissions this number increases to around 2.2 t CO2 per ton of steel.[5][6]

Energy Optimization Furnace

The Energy Optimization Furnace (EOF) is a variant of basic oxygen furnace. It consists of a scrap preheater located above the furnace roof, where sensible heat in the off-gas from the furnace is used for preheating scrap to around 850 to 900 °C . The process is essentially basic oxygen steelmaking where hot metal, scrap and direct reduced iron forms the charge.[7] An EOF also adds the possibility of tilting the furnace, which allows (a) continuous extraction of slag through the slag door; (b) continuous tapping at the very moment of finishing decarburizing; (c) the instantaneous release of scrap from the scrap pre-heater; (d) tap-to-tap times of even less than 30 minutes.[7]

Some of the plants that currently operate EOF units in their steel manufacturing facilities include JSW Steel Salem steel plant in Tamil Nadu, India, and Kalyani Steels Hospet plant in Karnataka, India.


  1. "Basic Oxygen Furnace (BOF) [SubsTech]". Retrieved 2023-12-19.
  2. "The Basic Oxygen Furnace - Reibus International". Retrieved 2023-12-19.
  3. "AIST Steel Wheel". Retrieved 2023-12-19.
  4. "Basic Oxygen Furnace Steelmaking". Retrieved 2021-06-29.
  5. Iron and Steel Technology Roadmap - Towards more sustainable steelmaking (IEA, 2020)
  6. Swalec, C. (2022). Pedal to the Metal. Global Energy Monitor.
  7. 7.0 7.1 "Energy Optimizing Furnace – IspatGuru". Retrieved 2024-03-27.

External links

This page uses material from the Wikipedia page Basic oxygen steelmaking under the provisions of the Creative Commons Attribution-ShareAlike 3.0 Unported License.

Abeckford21 (talk) 05:12, 29 June 2021 (UTC)