Slagreus – Reuse of slags from integrated steelmaking

Initial situation

  • In Europe about 10 Mio.t/year of BOF slag are produced at the steelmaking. A main part is reused for example in road construction. Nevertheless in 2016 about 23% are landfilled or stored temporarily.
  • Current discussions on environmental aspects are likely to impair the high percentage of utilisation in the traditional fields of application for steelmaking slags.

Working topics

  • An innovative process chain consisting of a primary liquid and a secondary solid enrichment will be investigated to gain an iron (Fe) enriched fraction with reduced phosphor content and a calcium (Ca) and phosphor (P)-enriched fraction.
  • The primary Fe enrichment is gained by liquid BOF slag treatment and by cooling of the slag to a slag temperature, which leads to a segregation of the solidified P-enriched slag fraction in the remaining Fe-enriched liquid slag.
  • The secondary Fe enrichment will be achieved by microwave supported comminution of the primary Fe-enriched slag, selective grinding and a magnetic separation.
  • An off-line prediction tool will be developed on the basis of the gained knowledge for the pre-treatment processes.

Results

  • A process chain will be developed to gain a Fe-enriched BOF slag fractions which can be used for internal recycling as substitute for primary raw materials.
  • A external utilisation of the Ca- and P-enriched slag fraction will be evaluated as cement additive as well as lime fertilizer.
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