Electrochemical Studies of Chromium in Molten LiF ‐ NaF ‐  KF  (FLINAK)

Abstract

The mechanism of the reduction of Cr(III) in molten FLINAK was studied using cyclic voltammetry and chronopotentiometry over a temperature range of 612°–983°C and a Cr(III) concentration of 0.07 to 0.13 mol/l. Two reduction and two oxidation steps were observed, but extensive differences in the electrochemistry were seen over the measured temperature range. Cr(III) is reduced to Cr(II) followed by a two‐electron reduction of Cr(II) to Cr metal and both reduction processes are quasi‐reversible. The product of the first reduction process is soluble at 983°C, but is insoluble at lower temperatures.

Salt extraction process–novel route for metal extraction Part 3–electrochemical behaviours of metal ions(Cr, Cu, Fe, Mg, Mn) in molten (CaCl2–)NaCl–KCl salt system

“…With respect to the electrochemical behaviour or electrodeposition of Cr(II) or Cr(III) in molten salt systems, most of them are investigated in chlorides or fluorides melts especially in LiCl-KCl, [3][4][5][6][7][8][9] NaCl, 10 CaCl 2 -NaCl, 11 NaCl-AlCl 3 , 12 and LiF-NaF-KF. [13][14][15] Several researches also have studied the electrochemical properties of iron species in molten chlorides, such as Fe(II) in LiCl-KCl system, 16 MgCl 2 -NaCl-KCl system 17 and ZnCl 2 -NaCl system 18 20 About the electrodeposition of FeCr alloy, Wang and Watanabe 21 have carried out the electrodeposition of Fe-Cr alloy film from the trivalent chromium bath containing glycine as complexing agent. However, no publication has been found in molten salts.…”

Pyrochemical process for electrochemically base metals in molten halides combined countercurrent electromigration and electrowinning methods

“…The quasi-reference electrode (QRE) was a platinum wire with 1.5 mm / as also used by other author [16]. In our experiments the Pt QRE showed a stable potential became it.…”

Electrochemical Investigation on the Stable Iron Species in Molten FLINAK

“…A/A' redox system: The cathodic current density of peak A (ip A ) obtained after subtracting the background current [22,23] linearly increases with the square root of the scan rate (v 1/2 ) as shown in Figure 4a, indicating that the first reduction step of Fe(III) is controlled by ion diffusion. In addition to the almost invariable peak potential (Ep A ) in the range of 0.1 to 1.0 V/s, the ratio of |ip A' /ip A | is approximately equal to 1, as shown in Table 1.…”