ArcelorMittal Ostrava’s Slag Recycling Project Reaps Many Rewards
The Czech Republic's Ministry of Industry and Trade recently announced the results of its competition “Transforming Waste into Resources". ArcelorMittal Ostrava/CZ project, which substituted the primary raw materials for steelmaking with specially processed recycled slag, ranked 4th in the competition of 127 contestants. A panel of experts from the Ministry of Industry and Trade, the Ministry of Education, universities, professional associations and unions assessed the entries. Steel production generates slag pellets as a by-product. While slag is a valuable source of iron, its phosphorus content limits its usefulness in the sintering process, because phosphorus reduces the quality of the resulting pig iron. So traditionally, very little slag was returned to the sintering process. By mechanically processing of the 0–8-mm steel slag which contains 35–40 % of iron, ArcelorMittal Ostrava was able to increase the slag`s iron content to 54–57 %, while keeping the phosphorus content low enough to reuse the enriched slag in the sintering process, replacing iron ore, additives and fuel in production. One tonne enriched slag replaces: 1027 t of ore, 336 kg of carbonate additives and fuel.
Using slag in this way increases the sustainability of the business’ operations, but also saves money compared to extracting and using primary natural resources. In 2016, ArcelorMittal Ostrava recycled monthly in average 1900 t enriched slag and in the process saved a total of over USD 865 000.