Investigation of the reaction progress between stannous chloride and zirconium in molten LiCl–KCl

Abstract

LiCl-KCl-ZrCl 4 melt was prepared by an in situ displacement reaction between SnCl 2 and Zr in LiCl-KCl melt at 773 K, and the progress of the reaction between SnCl 2 and Zr was also investigated by dynamic electrochemical measurements, such as cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. The results reveal that the concentration of Zr(IV) increases gradually and reaches a maximum value with the reaction time increasing from 0 to 210 min, while the concentration of Sn(II) decreases gradually and drops below the detection limit. In addition, the chemical analyses of Zr(IV) andSn(II) in the melt at various times were also carried out and the results are in good agreement with those of the electrochemical measurements. Finally, LiCl-KCl-ZrCl 4 melts with a low concentration of Sn(II) (<0.01 wt%) were obtained, when the reaction time was prolonged to 210 min.

In situelectrochemical investigation of the reaction progress between Zr and a CuCl–SnCl2mixture in a LiCl–KCl molten salt

“…2 shows the CVs of the LiCl-KCl melt on the molybdenum electrode aer the addition of 1.93 Â 10 À5 mol cm À3 CuCl (curve (a)), 1.01 Â 10 À5 mol cm À3 SnCl 2 (curve (b)), 1.93 Â 10 À5 mol cm À3 CuCl + 2.02 Â 10 À5 mol cm À3 SnCl 2 (curve (c)) and 1.64 Â 10 À5 mol cm À3 ZrCl 4 (curve (d)). As we know from our previous work, 13,19 A2/C2 in Fig. 2(a) corresponds to the deposition and oxidation peaks of Cu(I)/Cu, and A4/C4 in curve (b) is the redox peak of Sn(II)/Sn.…”

“…In addition, comparing the oxidation peak shapes and potentials of Cu-Zr and Sn-Zr alloys in our previous works 13,19 shows that the oxidation peaks of the Sn-Zr alloys are relatively sharp, and there is a certain distance from the reduction peak potentials of Sn-Zr alloys (approximately À0.70 V)) to the reduction peak potential of Zr (À0.90 V). The oxidation peaks of Cu-Zr alloys are relatively smooth, and one of the oxidation peaks at À0.80 V is close to the peak of Zr(IV)/Zr(II).…”

“…Moreover, the peak potentials of T/T 0 and B/B 0 also show a slight negative shi over time, which can be explained by the concentration decrease of Cu + and Sn 2+ during the chlorination reaction of Zr and CuCl-SnCl 2 . 19 When the reaction lasts 50 min, a new redox peak H/H 0 , according to Cu-Zr alloys, appears at À0.80 V. Then, another pair of redox peaks K/K 0 , according to Sn-Zr alloys, appears at approximately À0.50 V when the reaction proceeded to 100 min. The two pairs are more positive than the oxidation potential of zirconium in Fig.…”

“…17, 18 Murakami et al 16 investigated the preparation of a LiCl-KCl-ZrCl 4 melt by the reaction between CdCl 2 and Zr. The equilibration reactions between CuCl and zirconium, and SnCl 2 and zirconium to prepare ZrCl 4 in situ have been investigated in our previous work, 13,19 while Cu is solid and Sn is liquid at the operating temperature, the co-chlorination reaction between a binary mixture of CuCl-SnCl 2 and zirconium is important to clarify their co-chlorination progress and mechanism. Hence, the present work focused on the in situ preparation of ZrCl 4 by the chemical equilibration of zirconium with CuCl-SnCl 2 chlorides in the LiCl-KCl melt, which can be used as the electrolyte in the electrorening of Zr with the low-melting liquid alloy anode.…”

Electrochemical Reduction of Zirconium Oxide and Co-Deposition of Al-Zr Alloy from Cryolite Molten Salt

“…The alloys containing less than five atom% zirconium could be indexed to a disordered facecentered cubic structure, while the alloys containing approximately 17 atom% zirconium were completely amorphous (metallic glass). Besides the above-mentioned references, the electrochemical behavior of zirconium has also been studied in LiCl-KCl [15][16][17][18][19][20][21][22][23][24] and fluoride molten salts [25][26][27][28][29] by other researchers. Although the electrochemical behavior of zirconium has been widely studied in alkali molten salts, the electroreduction of Zr(IV) ions in a cryolite molten salt has not been studied.…”