Baosteel: Steelmaking slag treatment saves space, dust emissions and energy
Challenge
Steelmaking slag is an inevitable by-product from the steelmaking process, generated at a quantity equal to 10-15% of the steel produced.
If the iron- and steelmaking by-product slag is not sufficiently ground it cannot be used and is likely to be sent to landfill, which is costly. All traditional processes for steelmaking slag treatment in China are long flow processes and, due to their slow static cooling and granulation processes, occupy large swathes of land.
In addition, their open operation makes for high dust contamination. Finally, a large amount of energy is consumed for the cooled slag to be crushed, granulated and separated by magnetic force before it can be re-used. Molten slag can cause major environmental pollution even to a modern steel plant.
Action
Baosteel started to develop the Baosteel short slag treatment facility (BSSF) process for steelmaking slag treatment in 1995. In the BSSF process, high-temperature molten slag is treated in a special revolving container. Through the combined action of mechanical force and cooling, the slag is chilled until it becomes solid. It is then crushed into small particles.
Owing to their different freezing points, slag and residual metal solidify separately whilst inside the container. This prevents the metal from being mixed with the slag when they are discharged.
Outcome
The BSSF process is different from traditional slag treatment processes because of its closed operation, dynamic chilling, and hot granulating delivery of the finished slag. The finished slag is of even size, directly reusable and provides stable performance.
It has caught the attention of the metallurgical industry internationally. Other than at Baosteel’s own facilities, commercial BSSF operations have been installed at large- and medium-sized metallurgical enterprises in China, including Masteel (Maanshan Iron & Steel Company) and Jiuquan Iron & Steel Company. JSW in India has also adopted the process developed by Baosteel.
The BSSF process is an efficient process for steelmaking slag treatment. It provides emissions reductions, improved slag reuse rates and energy savings, all in one.
Last updated: May 2010
