Influence of the Recirculation of Various by-products Generated through Electric Arc Furnace Route on EAF Slag Quality

The Fines2EAF project aims to increase the value of Electric Arc Furnace steelmaking residues by their internal recycling and reuse in form of cement-free briquettes. The project sustainability for a profitable fines' recirculation pass through the conservation of steel and slag quality in terms of chemistry, physics and eco friendliness. To do this, industrial trials have been conducted by the charging of self-reducing and slag-former briquettes made by primary and secondary fines materials. Several slag samples supplied from three different European EAF steel shops have been analysed. The specimens have been characterized by XRF, XRD and SEM to thoroughly define their crystallography, morphology and microstructure. The comparison with the corresponding reference samples (i.e., slag produced without the fines recirculation) also allowed to highlight the differences present. Leaching tests have been conducted on reference and briquette- added slag according to EN 12457-4 standard to assess the compliant with the local environmental regulation. The obtained results highlighted that the slag obtained using cement-free briquettes made by steelmaking fines exhibits crystallographic and morphological properties very similar to the reference samples, with limited differences attributed to slag and scrap feedstock intrinsic heterogeneity. No relevant increase in the leachate concentration could be detected when compared to reference samples and the influence of raw-material fines recirculation into the EAF could be considered at worst negligible, if not positive for some elements like Ba ( - 22.86%), V ( - 13.19%) and W ( - 14.83%). Considering all the analyses performed, no adverse effect on slag quality could be detected

Developing a new process to agglomerate secondary raw material fines for recycling in the electric arc furnace - The fines2EAF project

Recent years have seen a worldwide change in the environmental policy towards circular economy approaches. It is estimated that steel-making activities in Europe produce about 80 million tonnes annually of by-products and waste, equivalent to half of the European steel production, of which more than 10 million tonnes is waste for disposal. This waste of resources and land area is not sustainable and has to be decreased in the future. The Fines2EAF project aims to increase the value of steelmaking residues by internal recycling and (re)use in the form of agglomerates. The benefit of this strategy is threefold: improved utilization of residues, internal recovery of valuable materials and reduction of the amount of dumped materials. The approach followed is the development of an innovative process to produce cement-free agglomerates based on primary and secondary raw material fines, alternative binder systems and a hydraulic stamp press. In addition, a new pre-treatment process for fines based on microwave heating is investigated. The first results of the lab-scale investigation of the fines pre-treatment to reduce the amount of zinc, volatiles and alkalis are presented. Six materials from two steel plants have been tested in a laboratory microwave furnace. Also presented are first results of the agglomeration of fines using a laboratory press

Developing a new process to agglomerate secondary raw material fines for recycling in the electric arc furnace - the Fines2EAF project

Recent years have seen a worldwide change in the environmental policy towards circular economy approaches. It is estimated that steel-making activities in Europe produce about 80 million tonnes annually of by-products and waste, equivalent to half of the European steel production, of which more than 10 million tonnes is waste for disposal. This waste of resources and land area is not sustainable and has to be decreased in the future. The Fines2EAF project aims to increase the value of steelmaking residues by internal recycling and (re)use in the form of agglomerates. The benefit of this strategy is threefold: improved utilization of residues, internal recovery of valuable materials and reduction of the amount of dumped materials. The approach followed is the development of an innovative process to produce cement -free agglomerates based on primary and secondary raw material fines, alternative binder systems and a hydraulic stamp press. In addition, a new pre-treatment process for fines based on microwave heating is investigated. The first results of the lab-scale investigation of the fines pre-treatment to reduce the amount of zinc, volatiles and alkalis are presented. Six materials from two steel plants have been tested in a laboratory microwave furnace. Also presented are first results of the agglomeration of fines using a laboratory press