Selective Leaching of Inert Mineral Product and the RO Phase in Steel Slag with Acetum to Improve Total Fe Content

Abstract

The chemical and mineral components of the leaching residues obtained during the leaching of inert mineral product (IMP) and two samples of divalent metal oxide continuous solid solution (RO phase) by acetum at 20 °C were analyzed to reveal the selective leaching characteristics of the chemical and mineral components in steel slag, and clarify the leaching rates and differences of MgO and FeO in the RO phase. The results indicated that the content of total Fe (TFe) in the leaching residue increased, whereas the contents of CaO, SiO2, and MgO decreased during the leaching of the inert mineral product by acetum. Fe3O4 was insoluble in acetum. The leaching rates of the RO phase and metallic Fe were very low, while those of calcium silicate (C2S + C3S) and dicalcium ferrite (C2F) were quite high. MgO and FeO in the RO phase continuously leached over time, and the leaching rate of MgO reached 1.9 times that of FeO. Therefore, during the leaching of the RO phase by acetum, the FeO content increased, whereas the MgO content decreased. In conclusion, acetum leaching can effectively improve the TFe content of the RO phase and the inert mineral product.

Determination of Fe3O4 Content and Total Nonhydraulic Minerals in Steel Slag

“…This process aims to enhance the relative content of hydrated active minerals (C 2 S, C 3 S) in steel slag powder and significantly improve its activity level. The highly active steel slag obtained after separation can achieve an activity index equivalent to S75 grade slag powder [10], while the nonhydraulic mineral product resulting from acetic acid solution leaching has a total iron (TFe) content of approximately 57.17%, meeting the minimum TFe content requirement (53.0%) specified in the iron concentrate standard, thus making it suitable for utilization as raw materials in iron production [11]. The accurate determination of the nonhydraulic mineral content is essential for evaluating the quality of both products and assessing the effectiveness of the separation process.…”