Hydration Activity and Expansibility Model for the RO Phase in Steel Slag

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Vol. 51; no. 4; pp. 1697 - 1704
• Main Authors: Hou, Jiwei, Chen, Zhimin, Liu, Jiaxiang
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2020; Springer Nature B.V
• Subjects: Autoclaving; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composition; Hydration; Magnesium oxide; Materials Science; Metal oxides; Metallic Materials; Nanotechnology; Slag; Solid solutions; Structural Materials; Surfaces and Interfaces; Thin Films
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-020-01847-3

The low hydration activity and volumetric instability of steel slag (SS) limits its application as a binding material. SS contains approximately 30 pct of a divalent metal oxide solid solution (RO phase). According to the XRD results of the RO phase extracted from SS, RO phases (MgO· x FeO) with different compositions were synthesized to study their hydration activity and expansibility. The hydration activity of the RO phase was found to exponentially decrease with the increasing molar ratio ( x ) of FeO to MgO in the RO phase. When x  ≥ 1 .5, the RO phase could not be hydrated after autoclaving at 215 °C and 2 MPa for 3 hours. The RO phase was blended into cement to study the relationships among the expansibility and composition and content of the RO phase via an autoclave test. When x  ≤0.5, more than 5 pct of the RO phase cracked the specimen. When 0.5 <  x  < 1.5, the autoclave expansion rate of the specimen decreased with the increasing value of x in the RO phase. When x  ≥ 1.5, the autoclave expansion rate of the specimen linearly increased with the content of the RO phase and was independent of the composition of the RO phase.