Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

The local structure of dilute CrCl3 in a molten MgCl2:KCl salt was investigated by in situ x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800oC. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl3 was confirmed to be the stable species between 200 and 500oC, while mobility of metal ions at higher temperature (>700oC) prevented confirmation of the local structure.