Preparation of ZrMn2 hydrogen storage alloy by electro-deoxidation in molten calcium chloride

Electrochemical Preparation of ZrFe2 and ZrFe1.8Ni0.2 Intermetallic Compounds by FFC Cambridge Process

“…Some of the reaction intermediates, such as Fe 23 Zr 6 , Zr 6 Fe 3 O and Zr 2 Fe, observed in the present study make the mechanistic pathway of reduction of Zr-Fe mixed oxides interesting and different compared to previous works on electrochemical preparation of Zrbased intermetallic compounds, wherein the pathway of reduction proceeded through direct formation of individual metals followed by intermetallic formation. 11,19 Apart from XRD, the electrolysed products were characterized by SEM-EDS. SEM images of the electrolysed products of different durations are depicted in Figs.…”

“…[13][14][15][16] Recently, FFC Cambridge process has been successfully applied for the preparation of advanced materials and alloys such as Ta-Nb, Ti-Nb, Ti-5Ta-Nb, Ti-Nb-Sn, TiNbTaZr, CoCrFeNi, and various hydrogen storage alloys, such as LaNi 5 , CeCo 5 , CeNi 5 , TbNi 5 , ZrCr 2 and ZrMn 2 . 11,[17][18][19][20][21][22][23][24][25][26][27] Peng et al synthesized Zr-based AB 2 -type hydrogen storage alloys (HSAs) viz., ZrCr 2 , ZrCr 0.7 Ni 1.3 , and Zr 0.5 Ti 0.5 V 0.5 Cr 0.2 Ni 1.3 from respective mixed oxide precursors via molten salt electrolysis in CaCl 2 melt at 900 o C. 11 Electrolysis energy consumption as low as 9.59 kWh (kg-HSA) −1 and a metal recovery yield greater than 90% was reported. The reduction proceeded through CaZrO 3 , elemental Zr and Cr as reaction intermediates.…”

“…The reduction proceeded through CaZrO 3 , elemental Zr and Cr as reaction intermediates. Dai et al electro-synthesized ZrMn 2 directly from cathode pellets made of MnO 2 and ZrO 2 in a molten calcium chloride medium at 900 o C. 19 The electrolysis was conducted with a mixed oxide pellet at 3.1 V for 12 h to achieve pure ZrMn 2 . Electrodeoxidation pathway proceeded through the reduction of manganese oxide to Mn, followed by ZrO 2 or CaZrO 3 reduction on the preformed Mn to ZrMn 2 alloy.…”

The Electrolytic Reduction of Gd2O3 in LiCl-KCl-Li2O Molten Salt

“…4,5 Advantages of FFC process are as follows: (i) low energy consumption, (ii) easy to obtain metal oxides as raw materials. At present, the research of FFC process mainly focused on high melting point transition metals such as Ti, [5][6][7][8][9] Zr, [10][11][12] Fe, 13 Hf, 14 V, 15 Nb, 16,17 Ta, 18,19 Ni, 20 rare earth elements such as La, 21 Ce, 22 Tb, 23 Dy, 24 Yb 25 and actinides such as U. 1,[26][27][28][29][30][31] Some researchers have also studied the electro-deoxidation of C, 32 Si 33 and other non-metallic oxides.…”

“…The alkali metal and alkaline earth metal oxides are added to the salt and reduced to metal on the cathode during electrolysis, and they continue to react with the cathodic oxides and reduce them. 27,34 In the aspect of electrolyte, because of the high solubility of O 2− ion and liquid metal Ca in CaCl 2 , 4,7,8,35 the molten salt of CaCl 2 system was widely used at first, such as CaCl 2 [4][5][6]10,14,16,18,21,[23][24][25]33,34 and CaCl 2 -CaO 8,20,29,31,32 etc., but these molten salts have high melting point. The higher operating temperature not only leads to higher cost of energy and equipment, 28 but also makes the cathode more compact, which will block the migration of oxygen ions in the cathode.…”