1. Tangshan Iron and Steel Co., Ltd., Tangshan 063016, China 2. Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai 200072, China
Abstract：A new process of solid oxygen-ion membrane process was used for the production of LaNi4Al alloy directly from La2O3-NiO-Al2O3 sintered pellet. Cathode and anode was separated from a yttria-stabilized zirconia tube in which only oxygen-ion was permeated so the voltage was as high as 3.8 V to achieve high deoxidization rate. The morphology, phase composition, corrosion of the sintered pellets in the molten salt were examined, the reduction mechanism was investigated by analyzing the phase constitution of the intermediate product. The results show that direct electrochemical reduction La2O3-NiO-Al2O3 sintered pellet to the LaNi4Al alloy by SOM process is feasible. At sintering temperature of 1 150 ℃, sintered pellet starts from LaAlO3 reacts with CaCl2 into LaOCl and Al, NiO is deoxidized into Ni, then reacting with LaOCl and Al into LaNi4Al. The current efficiency is 92.7%, the electrolysis energy consumption is as low as 3.55 kW·h/kg. It is concluded that SOM process has a bright future for industrial application because of its short process and high efficiency.
[1] P. Termsuksawad, S. Niyomsoan, B. Mishra, D. L. Olson, Z. Gavra, V. I. Kaydanov. Prediction of hydrogen absorption behavior in AB5 hydrogen storage alloys by electronic techniques [J]. Materials Science and Engineering B, 2005, 117(1): 45-51[2] 蔚如意, 李全安, 李克杰. AB5型贮氢合金的合金化研究进展[J]. 稀有金属材料与工程, 2007, 36(6): 1124-1128[3] 张芙蓉, 马立群, 丁毅, 赵相玉. AB5型储氢合金的研究进展[J]. 材料导报, 2007, 21(4): 309-312[4] Chen G Z, Fray D J, Farthing T W. Direct Electrochemical Reduction of Titanium Dioxide to Titanium in Molten Calcium. Nature, 2000, 407(9): 361-364[5] Chen G Z, Elena Gordo, Fray D J. Direct Electrolytic Preparation of Chromium Powder, Metallurgical and Materials Transactions, 2004, 35(2): 223-232[6] Wang Dihua, Qiu Guohong, Jin Xianbo, Hu Xiaohong, Chen G Z. Electrochemical Metallization of Solid Terbium Oxide. Angew. Chem. Int. Ed, 2006, 45(15): 2384-2388[7] XU Qian, DENG Liqin, WU Yan, Ma Tao. A study of cathode improvement for electrodeoxidation of Nb2O5 in a eutectic CaCl2-NaCl melt at 1073K. Journal of Alloys and Compounds, 2005, 396: 288-294[8] 胡小峰, 许茜. CaCl2-NaCl熔盐电脱氧法制备金属Ta.金属学报. 2006, 42(3): 285-289[9] ZHU Yong, MA Meng, WANG Dihua, Jiang Kai, Hu Xiaohong, Jin Xianbo, Chen G Z. Electrolytic reduction of mixed so1id oxides in molten salts for energy efficient production oroductlon of the TiNi Alloy. Chinese Science Bulletin, 2006, 51: 2535-2540[10] Glowacki B A, Fray D J, Yan X Y. Superconducting Nb3Sn intermetallics made by electrochemical reduction of Nb2O5-SnO2 oxides, Physica C, 2003, 387(1): 242-246[11] Qiu Guohong, Wang Dihua, Ma Meng , Jin Xianbo, Chen G Z. Electrolytic synthesis of TbFe2 from Tb4O7 and Fe2O3 powders in molten CaCl2. Journal of Electroanalytical Chemistry, 2006, 589(1): 139-147[12] QIU Guohong, WANG Dihua, JIN Xianbo, Chen G Z. A direct electrochemical route from oxide precursors to the terbium–nickel intermetallic compound TbNi5. Electro- chimica Acta, 2006, 51(26): 5785-5793[13] ZHAO B J, WANG L, DAI L, et al. Direct electrolytic preparation of cerium/nickel hydrogen storage alloy powder in molten salt[J]. Journal of Alloys and Compounds, 2009, 468(1): 379-385.[14] 何理, 鲁雄刚, 陈朝轶, 等. 固体透氧膜法制备金属铌[J]. 中国有色金属学报, 2008, 18(7): 1336-1341.[15] 陈朝轶, 鲁雄刚, 李谦, 等. 固体透氧膜法与熔盐电解法制备金属铬的对比[J]. 金属学报, 2008, 44(2): 145-149.[16] 陈朝轶, 鲁雄刚, 李谦, 程红伟. 利用SOM 法制备金属钽[J]. 稀有金属材料与工程, 2007, 36(11): 1991-1995[17] 赵炳建, 鲁雄刚, 李重河, 等. 固体透氧膜法直接还原NiO-CeO2制备CeNi5合金[J]. 金属学报, 2009, 45(10): 1255-1260.[18] ZHAO B J, LU X G, ZHONG Q D, et al. Direct Electrochemical Preparation of CeNi5 and LaxCe1-xNi5 Alloys from Mixed Oxides by SOM Process[J]. Electrochimica Acta, 2010, 55(8): 2996-3001.[19] Elena G, Chen G Z, Fray D J. Toward optimization of electrolytic reduction of solid chromium oxide to chromium powder in molten chloride salts[J]. Electrochimica Acta, 2004,49(13): 2195-2208[20] ZHU Y, WANG D H, MA M, HU X H, JIN X B, CHEN G Z. More affordable electrolytic LaNi5 type hydrogen storage powders[J]. Chemical Communications, 2007, 24: 2515-2517
2015, Vol. 25 
