New EAF Slag Characterization Methodology for Strategic Metal Recovery

Abstract

The grown demand of current and future development of new technologies for high added value and strategic metals, such as molybdenum, vanadium, and chromium, and facing to the depletion of basic primary resources of these metals, the metal extraction and recovery from industrial by-products and wastes is a promising choice. Slag from the steelmaking sector contains a significant amount of metals; therefore, it must be considered to be an abundant secondary resource for several strategic materials, especially chromium. In this work, the generated slag from electric arc furnace (EAF) provided by the French steel industry was characterized by using multitude analytical techniques in order to determine the physico-chemical characteristics of the targeted slag. The revealed main crystallized phases are larnite (Ca2SiO4), magnetite (Fe3O4), srebrodolskite (Ca2Fe2O5), wüstite (FeO), maghemite (Fe2.6O3), hematite (Fe2O3), chromite [(Fe,Mg)Cr2O4], and quartz (SiO2). The collected slag sample contains about 34.1% iron (48.5% Fe2O3) and 3.5% chromium, whilst the vanadium contents is around 1500 ppm. The Mössbauer spectroscopy suggested that the non-magnetic fraction represents 42 wt% of the slag, while the remainder (58 wt%) is composed of magnetic components. The thermal treatment of steel slag up to 900 °C indicated that this solid is almost stable and few contained phases change their structures.

Characterization and Mössbauer spectroscopy of steel slag generated in the ladle furnance in SIDERPERU steel plant

“…Furthermore, the non-stoichiometric ankerite might have formed during the reaction of MnO, CaO and SiO 2 . These mineralogical phases are commonly found in steel slag reported in literature [7,8,15,16]. The results obtained here are in agreement with the EDX and XRF analysis above, which registered Fe and Ca as the major components.…”

Characterization of black slags obtained during smelting in the electric arc furnace from SIDERPERU following reduction

“…FeO, ICSD card No.01-073-2143). These components are in good agreement with the composition of EAF slags reported in the surveys performed by Teo et al and Menad et al[13,14] .Fig. 1(b) shows the XRD of the black slag sample after carbothermal reduction.…”

Direct Air Capture and Sequestration of CO2 by Accelerated Indirect Aqueous Mineral Carbonation under Ambient Conditions

“…4 Both stabilization and high mobility can potentially benefit the use of carbonated residues in structural applications and recovery of "strategic elements", respectively. 38,39 Understanding the leaching characteristics of pollutants and their implications on the proposed process, which was beyond the scope of this study, would be addressed in future investigations.…”