Exploring the wettability of liquid iron on refractory oxides with sessile drop technique and density-functional derived Hamaker constants

TL;DR

This study combines density functional theory and dispersion force calculations to analyze the wettability of liquid iron on various refractory oxides, validated by experiments at high temperature, to improve metallurgical process efficiency.

Contribution

It introduces a novel methodology integrating dielectric response calculations with Hamaker constants to predict wettability of liquid iron on oxides.

Findings

Validated contact angles of liquid iron on oxides at 1823 K.

Confirmed crystalline structures with X-ray diffraction.

Compared wettability with a tin-bismuth alloy.

Abstract

The macroscopic interactions of liquid iron and solid oxides, such as alumina, calcia, magnesia, silica, and zirconia manifest the behavior and efficiency of high-temperature metallurgical processes. The oxides serve dual roles, both as components of refractory materials in submerged entry nozzles and also as significant constituents of non-metallic inclusions in the melt. It is therefore crucial to understand the physicochemical interplay between the liquid and the oxides in order to address the nozzle clogging challenges, and thereby optimize cast iron and steel production. This paper presents a methodology for describing these interactions by combining the materials' dielectric responses, computed within the density functional theory, with the Casimir-Lifshitz dispersion forces to generate the Hamaker constants. The approach provides a comprehensive understanding of the wettability of iron against these refractory oxides, revealing the complex relation between molecular and macroscopic properties. Our theoretically determined crystalline structures are confirmed by room-temperature X-ray diffraction, and the contact angles of liquid iron on the oxides are validated with a sessile drop system at the temperature 1823 K. For comparison, we also present the wettability of the oxides by a liquid tin-bismuth alloy. The findings are essential in advancing the fundamental understanding of interfacial interactions in metallurgical science, and are also pivotal in driving the development of more efficient and reliable steelmaking processes.