418499 Electroytic Reduction of Zirconium Oxide in Molten LiCl-Li2O to Study Mass Transport of Li2O

Tuesday, November 10, 2015: 9:40 AM
250B (Salt Palace Convention Center)
Adam Burak and Michael Simpson, Metallurgical Engineering, University of Utah, Salt Lake City, UT

Direct electrolytic reduction in molten chloride salt has been demonstrated for a number of different metal oxides. When using an electrolyte consisting of LiCl and Li2O, minimization of lithium oxide retention in the reduced product is important for process efficiency and product quality.  In this study, zirconium oxide reduction in this salt has been experimentally investigated. Cyclic voltammetry with a basket containing zirconium oxide as the working electrode was used to assess the relative importance of lithium oxide electrowinning versus direct electrolytic reduction of the zirconium oxide.  It is theorized that a high rate of direct ZrO2 reduction coupled with limited mass transport of Li2O will result in excessive Li2O buildup in the cathode basket. This effect was tested via electrolytic reduction experiments in which basket rotation and periodically interrupted cell current were used to minimize accumulation of Li2O in the cathode basket.  To provide data for future modeling, the solubility of metallic lithium was measured as a function of lithium oxide concentration in the lithium chloride.  The reported experiments were performed in an argon atmosphere glove box, with low oxygen and moisture concentrations.  All experiments were run at a temperature of 650°C.  Electrode potentials were measured and controlled versus a nickel/nickel oxide reference electrode. The anode used for these experiments was made of platinum wire and was purged with argon to enable continuous measurement of oxygen gas produced from the reaction.

Extended Abstract: File Not Uploaded