Direct electrochemical extraction of Ti5Si3 from pressed cathode pellets comprising of powdered Ti/Sicontaining
metal oxide compounds was investigated by using molten salt electro-deoxidation technology. Three
groups of mixtures including TiO2 mixed with SiO2, Ti-bearing blast furnace slag (TBFS) mixed with TiO2,
and TBFS mixed with high-titanium slag (HTS) were prepared at the same stoichiometric ratio (Ti : Si = 5 : 3)
corresponding to the target composition of Ti5Si3, and used as the starting materials in this experiment, respectively.
The pressed porous cylindrical pellet of the Ti/Si-containing compounds served as a cathode, and two
different anode systems, i.e., the inert solid oxide oxygen-ion-conducting membrane (SOM) based anode system
and graphite-based anode system were used contrastively. The electrochemical experiment was carried out at
900—1 050℃ and 3.0—4.0 V in molten CaCl2 electrolyte. The results show that the oxide components were
electro-deoxidized effectively and Ti5Si3 could be directly extracted from these complex Ti/Si-containing metal
oxide compounds.
ZOU Xing-li1 (邹星礼), LU Xiong-gang1* (鲁雄刚), XIAO Wei1 (肖玮), ZHOU Zhong-fu1,2 (周忠福), ZHONG Qing-dong1 (钟庆东), DING Wei-zhong1 (丁伟中)
. Direct Electrochemical Extraction of Ti5Si3 from Ti/Si-Containing Metal Oxide Compounds in Molten CaCl2[J]. Journal of Shanghai Jiaotong University(Science), 2013
, 18(1)
: 111
-117
.
DOI: 10.1007/s12204-013-1373-6
[1] Zhang L, Wu J. Ti5Si3 and Ti5Si3-based alloys: Alloying behavior, microstructure and mechanical property evaluation [J]. Acta Materialia, 1998, 46(10): 3535-3546.
[2] Xu J, Liu L, Lu X, et al. Effect of carbon doping on electrochemical behavior of nanacrystalline Ti5Si3 film in NaCl solution [J]. Electrochemistry Communications, 2011, 13(1): 102-105.
[3] Kishida K, Fujiwara M, Adachi H, et al. Plastic deformation of single crystals of Ti5Si3 with the hexagonal D88 structure [J]. Acta Materialia, 2010, 58(3): 846-857.
[4] Lin H K, Tzeng Y F, Wang C H, et al. Ti5 Si3 nanowire and its field emission property [J]. Chemistry of Materials, 2008, 20(7): 2429-2431.
[5] Schneibel J H, Rawn C J. Thermal expansion anisotropy of ternary titanium silicides based on Ti5Si3 [J]. Acta Materialia, 2004, 52(13): 3843-3848.
[6] Gu D, Shen Y, Lu Z. Preparation of TiN-Ti5Si3 insitu composites by selective laser melting [J]. Materials Letters, 2009, 63(18-19): 1577-1579.
[7] Yeh C L, Wang H J, Chen W H. A comparative study on combustion synthesis of Ti-Si compounds [J]. Journal of Alloys and Compounds, 2008, 450(1-2): 200-207.
[8] Boyer R R. Attributes, characteristics, and applications of titanium and its alloys [J]. Journal of the Minerals, Metals and Materials Society, 2010, 62(5): 21-24.
[9] Lu K. The future of metals [J]. Science, 2010,328(5976): 319-320.
[10] Allanore A, Feng J, Lavelaine H, et al. The adsorption of hematite particles on steel in strongly alkaline electrolyte [J]. Journal of the Eletrochemical Society, 2010, 157(3): E24-E30.
[11] Allanore A, Lavelaine H, Valentin G, et al. Observation and modeling of the reduction of hematite particles to metal in alkaline solution by electrolysis [J]. Electrochimica Acta, 2010, 55(12): 4007-4013.
[12] Chen G Z, Fray D J, Farthing T W. Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride [J]. Nature, 2000, 407: 361-364.
[13] Krishnan A, Lu X G, Pal U B. Solid oxide membrane process for magnesium production directly from magnesium oxide [J]. Metallurgical and Materials Transactions B, 2005, 36B(4): 463-473.
[14] Pal U B, Woolley D E, Kenney G B. Emerging SOM technology for the green synthesis of metals from oxides [J]. Journal of the Minerals, Metals and Materials Society, 2001, 53(10): 32-35.
[15] Lu X, Zou X, Li C, et al. Green electrochemical process solid-oxide oxygen-ion-conducting membrane (SOM): Direct extraction of Ti-Fe alloys from natural ilmenite [J]. Metallurgical and Materials Transactions B, 2012, 43B(3): 503-512.
[16] Zou X, Lu X, Li C, et al. A direct electrochemical route from oxides to Ti-Si intermetallics [J]. Electrochimica Acta, 2010, 55(18): 5173-5179.
[17] Zou X, Lu X, Zhou Z, et al. Direct selective extraction of titanium silicide Ti5Si3 from multi-component Ti-bearing compounds in molten salt by an electrochemical process [J]. Electrochimica Acta, 2011, 56(24): 8430-8437.
[18] Zou X, Lu X, Zhou Z, et al. Direct electrosynthesis of Ti5Si3/TiC composites from their oxides/C precursors in molten calcium chloride [J]. Electrochemistry Communications, 2012, 21(1): 9-13.
[19] Nohira T, Yasuda K, Ito Y. Pinpoint and bulk electrochemical reduction of insulating silicon dioxide to silicon [J]. Nature Materials, 2003, 2: 397-401.
[20] Wang D, Jin X, Chen G Z. Solid state reactions: An electrochemical approach in molten salts [J]. Annual Reports on the Progress of Chemistry, Section C: Physical Chemistry, 2008, 104: 189-234.
[21] Alexander D T L, Schwandt C, Fray D J. Microstructural kinetics of phase transformations during electrochemical reduction of titanium dioxide in molten calcium chloride [J]. Acta Materialia, 2006, 54(11): 2933-2944.
[22] Xiao W, Jin X, Deng Y, et al. Three-phase interlines electrochemically driven into insulator compounds: A penetration model and its verification by electroreduction of solid AgCl [J]. Chemistry: A European Journal, 2007, 13(2): 604-612.
[23] Deng Y,Wang D, XiaoW, et al. Electrochemistry at conductor/insulator/electrolyte three-phase interlines: A thin layer model [J]. The Journal of Physical Chemistry B, 2005, 109(29): 14043-14051.
[24] Xiao W, Jin X, Deng Y, et al. Electrochemically driven three-phase interlines into insulator compounds: Electroreduction of solid SiO2 in molten CaCl2 [J]. ChemPhysChem, 2006, 7(8): 1750-1758.
[25] Ma M, Wang D, Wang W, et al. Extraction of titanium from different titania precursors by the FFC Cambridge process [J]. Journal of Alloys and Compounds, 2006, 420(1-2): 37-45.
[26] Suzuki R O, Aizawa M, Ono K. Calciumdeoxidation of niobium and titanium in Ca-saturated CaCl2 molten salt [J]. Journal of Alloys and Compounds, 1999, 288(1-2): 173-182.
[27] Suzuki R O. Calciothermic reduction of TiO2 and in situ electrolysis of CaO in the molten CaCl2 [J]. Journal of Physics and Chemistry of Solids, 2005, 66(2-4): 461-465.
