SAKAGUCHI Hiroki Osaka University, Faculty of Engineering, Research Associate, 工学部, 助手 (00202086)
IMANAKA Nobuhito Osaka University, Faculty of Engineering, Research Associate, 工学部, 助手 (30192503)
MACHIDA Kenichi Osaka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00157223)
|Budget Amount *help
¥13,800,000 (Direct Cost : ¥13,800,000)
Fiscal Year 1994 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1993 : ¥12,000,000 (Direct Cost : ¥12,000,000)
A dry process for recovery of rare metals from (i) sludges of Sm_2Co_<17>, Nd_2Fe_<14>B,and LaNi_5 intermetallic compounds and (ii) fly ash of bitumen-in-water emulsion was investigated using chemical vapor transport along a given temperature gradient. Chlorine gas and aluminium chloride were used as a chlorinating agent and transporting agent, respectively, and rare metal chlorides were chemically transported via vapor complexes, RAl_nCl_<3+3n> (R=rare earths) and MAI_nCl_<2+3n> (M=Co, Ni, Mg) /
The sludges of intermetallic compounds were chlorinated at 1000ﾟC yielding the RCl_3 and MCl_2. By the transport reaction, rare earth chlorides were concentrated in the deposits in the higher temperature zone (800-900ﾟC) while CoCl_2 and NiCl_2 were in the lower temperature zone (500-700ﾟC) .Purity of each of the recovered chlorides was more than 99%. Chlorides of other transition metals were concentrated at the outlet of the reactor (below 350ﾟC) without any contamination for the recoveries. Y
ields of Ni and Co were more than 99%after transport reaction for 6 hours, whereas those of La, Sm, Nd, and Dy were lower, i, e.27,39,59, and 68%, owing to the relatively low formation rate of RAl_nCl_<3+3n> complexes.
The fly ash of bitumen-in-water emulsion was chlorinated at 500-600ﾟC.Vanadium in the ash was thoroughly extracted as chloride and condensed at the temperature zone<80ﾟC without using the transporting agent, Al_<>Cl_6 (g) , only by chlorination at 500ﾟC.Nickel and magnesium chloride which are less volatile were chemically transported via the vapor complexes. The yields of Ni and Mg were 67 and 91%, respectively, whereas 27 and 0.1% in the absence of the aluminium chloride. When a linear temperature gradient was employed, the deposition of the NiCl_2 at the temperature range 210-400ﾟC was overlapped with that of MgCl_2 at 170-400ﾟC.On the contrary, the use of a temperature gradient with a constant temperature zone at 410ﾟC rendered it possible to separate mutually the NiCl_2 and MgCl_2.
In order to postulate the structure of RAl_3Cl_<12> vapor complexes, Raman spectra of molten RCl_3-AlCl_3 mixture was carried out. The spectra shows the coordination of the rare earth is 9-fold for Nd and 8-fold for Gd, suggesting the same coordination number for NdAl_3Cl_<12> and GdAl_3Cl_<12> vapors. Less