Slagreus – Reuse of slags from integrated steelmaking
The Fe-enriched product will be a substitute for iron ore fines. For the ladle furnace slag a dry and rapid cooling process will be developed and will be used as internal lime substitute in the ladle furnace without a hydrogen contamination of the steel. The remaining reactive calcium silicate rich fractions will be evaluated as cement additive and partly as lime fertilizer.
- 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
- 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.
- 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
- External utilisation of the Ca- and P-enriched slag fraction will be evaluated as cement additive as well as lime fertilizer