Combating the acidification of the environment

Emissions of sulphur dioxides and nitrogen oxides cause acidification of the environment. Because this is a cross-border problem, international agreements have been made.

The National Emission Ceilings Directive is a European directive that obliges each member state to reduce the emissions of sulphur dioxides and nitrogen oxides (but also of volatile organic compounds and ammonia) to a fixed value.

In Belgium, the necessary efforts are divided among different sectors, including the steel industry. Steel production causes significant NOx and SO2 emissions. NOx emissions are formed by thermal processes at high temperatures, by combustion processes and by fuel-related facilities such as furnaces. SO2 emissions are intrinsic to the sulphur content of raw materials and coal used in the combustion and production processes.

Technologies to reduce those emissions and that can be applied in the steel industry are unfortunately not readily available. Still, ArcelorMittal Gent has already put in a great effort over the years.


NOx emissions

Over the years, absolute NOx emissions have remained fairly constant in spite of the significant increase in production. Specific NOx emissions per tonne of produced liquid steel are even about 30% lower than 15 years ago. This important improvement was made possible by:

  • converting slab production process into a continuous process;
  • increasing the material yield;
  • improving the process in the coking plant;
  • using blast furnace gas for steam generation;
  • commissioning low NOx burners when constructing or converting furnaces;

using in the sinter plants a mixture of coke breeze and anthracite as fuel instead of only coke breeze.



SO2 emissions

Total SO2 emissions from the chimneys decreased over a period of some 25 years by 82%. ArcelorMittal Gent achieved this 82% reduction thanks to:

  • technological investments to boost the output of the existing facilities and new investments such as the construction of a continuous casting line and a pulverised coal injection unit (which account for 40% of the reduction);
  • the use of coal with a lower sulphur content and the reduction in the use of fuel (30% of the reduction);
  • the construction of a coke oven gas desulphurisation facility in the coking plant (which accounts for 12%).

The most recent measure was replacing coke breeze by anthracite with low sulphur content as fuel in the sinter plants.




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