BOF Bottom Stirring

BOF Bottom Stirring, also referred to as as combined blowing) involves the the introduction of small amount of inert gas from the furnace bottom and is regarded as one of the major innovations for the process.  The injected gas provides mild stirring of the bath during and after top blowing with oxygen and promotes a desirable carbon-oxygen equilibrium in the bath and slag. Bottom stirring improves BOF yield (reduced slag formation), reduces oxygen and flux consumption, and increases vessel life. It also improves product quality - by allowing lower oxygen and carbon content. Some BOF converters have more have more advanced injection systems where oxygen, flux and other gases are injected from the bottom of the converter.  

Industry experts state that maintaining effective stirring continues to be a major inconvenience in many shops that have tried the technique. Nevertheless, this technique is regarded to have a high applicaiton potential for China, India and the US.  

Development Status Products

BOF Bottom StirringCosts & Benefits

Parent Process: Basic Oxygen Furnace
Energy Savings Potential

Flux quantities are reduced by more than 10%. Less Iron is Lost to slag. Oxygen consumption is reduced.

CO2 Emission Reduction Potential

Costs can be reduced because Vacuum Treatment process is not required. Vessel life is also prolonged.

BOF Bottom StirringSchematic

BOF Bottom Stirring Publications

The State–of-the-Art Clean Technologies (SOACT) for Steelmaking Handbook


The State–of-the-Art Clean Technologies (SOACT) for Steelmaking Handbook is developed as part of the Asia-Pacific Partnership on Clean Development and Climate program and seeks to catalog the best available technologies and practices to save energy and reduce environmental impacts in the steel industry. Its purpose is to share information about commercialized or emerging technologies and practices that are currently available to increase energy efficiency and environmental performance. 

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