Purification of nuclear grade Zr scrap as the high purity dense Zr deposits from Zirlo scrap by electrorefining in LiF–KF–ZrF4 molten fluorides

Morphology Change Of Si Deposit In Molten Salt Electrorefining

“…Potassium is supposed to be reduced at a much lower reduction potential than -0.5 V, but potassium could be reduced at such a high potential because of the high vapor pressure of potassium at the electrolysis temperature of 800 • C in this study as reported by G. J. Kipouros [11]. Silicon also easily forms intermetallic compounds such as KSi, K 12 Si 17 , K 8 Si 46 , K 7 Si 46 with potassium [12], which leads to reduction of silicon at a more positive potential than its standard potential, the so-called under potential deposition. The other possible explanation is that potassium could be more easily reduced as the concentration of KF increased as K 2 SiF 6 was decomposed into KF and SiF 4 .…”

“…The shape of a deposit of silicon is important according to the application. When the purpose of the electrorefining is to recover a high purity product, the cathode deposit is coarse with high density due to minimized surface oxidation and incorporation of an electrolyte containing impurities [6,7]. In particular, the grain boundary is an important structural place where impurities are segregated [8].…”

Investigation on the reaction progress of zirconium and cuprous chloride in the LiCl–KCl melt

“…Although the high-purity zirconium with a total content of impurities up to 10 À6 can be obtained by this process, the iodide process is expensive and not very productive, and should be replaced by more promising methods. The electrorefining process based on molten salt containing zirconium chlorides or fluorides has been developed as a promising option for refining of zirconium from impure zirconium metal, alloy or spent metal fuels [2,3].…”

“…The chosen of the liquid alloy anode can not only reduce the operating temperature, but also expect to provide a low cost and semi-continuous process for production nuclear grade zirconium. The electrorefining and electrochemical process of Zr has been studied in various molten salt systems, including all-chloride baths such as LiCl-KCl-ZrCl 4 [2,[5][6][7], KCl-ZrCl 4 [8,9], all-fluoride baths such as LiF-NaF-KF-ZrF 4 and K 2 ZrF 6 [10,11], LiF-KF-ZrF 4 [3], LiF-CaF 2 -ZrF 4 [12] and chloridefluoride-mixed baths such as KCl-NaCl-ZrF 4 [13], KCl-NaCl-K 2 ZrF 6 [8,13,14], and LiCl-KCl-K 2 ZrF 6 [15] at temperature ranges of 450 C to 750 C. However, the operating temperature of the all-fluoride baths is 100 C $ 200 C higher, and the corrosion issue is more severe compared to those of all-chloride baths. In consideration of the melting point of liquid alloy anode and a moderate experimental condition, the Zr electrorefining process is proposed in LiCl-KCl-ZrCl 4 molten salt at 500 C in the initial stage of research.…”

Effect of Zr Purity and Oxygen Content on the Structure and Mechanical Properties of Melt-Spun and Suction-Cast Cu46Zr42Al7Y5 Alloy

“…Zirconium and hafnium are chemically similar elements and it is very difficult to separate Hf from Zr scrap. Moreover high purity Zr, with oxygen content below 100 ppm, is regarded as the only material that can be used as a cladding material for nuclear fuel because it has the lowest neutron capture cross section of any metal element [24]. Therefore high purity Zr, with oxygen below 100 ppm and Hf free, is not commercially available.…”