A review of in-situ high-temperature characterizations for understanding processes of metallurgical engineering

For rationally manipulating the production quality of high-temperature metallurgical engineering, there are great challenges in understanding the processes owing to the dark-box chemical/electrochemical reactors. To overcome this issues, various in-situ characterization methods have been recently developed to study the interactions between the composition, micro-structure and solid-liquid interface of high-temperature electrochemical electrodes and molten salts. In this review, recent progresses of in-situ high-temperature characterization techniques are discussed to summarize the advances of understanding processes in metallurgy engineering. In-situ high-temperature technologies and analytic methods mainly include synchrotron X-ray diffraction (s-XRD), laser confocal microscopy (LSCM) and X-ray computed microtomography imaging (CT), which are important platform for analyzing the structure and morphology of the electrodes to reveal the complexity and variability of the electrode interfaces. In addition, laser-induced breakdown spectroscopy (LIBS), high-temperature Raman microspectroscopy and ultraviolet-visible spectroscopy (UV-vis) provide microscale characterizations on the composition and structure of molten salts. More importantly, the combination of CT and s-XRD techniques enables to investigate the chemical reaction mechanisms at the two-phase interface. Therefore, these in-situ methods are essential for analyzing the chemical/electrochemical kinetics of high-temperature reaction processes, establishing theoretical principles for the efficient and stable operation of chemical/electrochemical metallurgical processes.