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Volume change of core-shell droplets of liquid iron and molten oxide under microgravity conditions
Irori Matsumoto, Reina Sato, Masahito Watanabe and Taishi Matsushita
Interfacial phenomena occur when two immiscible liquids contact each other, and they are of interest in various scientific and technological fields. Understanding and observing the interfacial phenomena between molten oxide and liquid iron (Fe) is crucial for process control in steel manufacturing. We study interfacial phenomena by observing the surface oscillation of compound droplets comprising molten oxide and liquid Fe in the electrostatic levitation furnace (ELF) aboard the International Space Station. Compound droplets form core-shell droplets under microgravity conditions due to the absence of density differences. During onboard experiments using the ELF, we created core-shell compound droplets comprising molten oxide (SiO2:CaO:Mn3O4:TiO2:Fe2O3 = 25:7:20:18:30 mass%) and liquid Fe in an Ar atmosphere. We observed increased droplet volume while observing the core-shell droplet oscillation phenomena at constant temperature. This expansion can be attributed to the dissolution of Fe from the core liquid to the shell molten oxides at the interface due to the oxidation of liquid Fe. It is necessary to investigate the volume changes of the core-shell droplet to clarify the hypothesis. We analyzed the volume change using the measured density of molten oxide when Fe was dissolved into the molten oxide using the aerodynamic levitation method on the ground. Through these analyses, we discuss the oxidation of liquid Fe at the interface with the molten oxide.
Keywords: compound droplet, molten oxide, liquid metal, electrostatic levitation, microgravity
DOI: 10.32908/hthp.v54.1929