Rare earth separation using a chemical vapour transport process mediated by vapour complexes of the LnCl3AlCl3 system

Comparative study for mutual separation characteristics of binary mixed oxides Y2O3–Ln2O3 (Ln=Dy, Ho and Er) and Ho2O3–Er2O3 using stepwise chlorination–chemical vapor transport reaction mediated by vapor complexes KLnCl4

“…The larger the difference of two kinds of lanthanide ion radii, the greater the separation factor of them by CVT or SC-CVT process. Both our experimental results of binary neighboring rare earth elements mediated by LnAl n Cl 3n+3 using CVT [12,13] or SC-CVT [14][15][16][17] and Adachi's results [1][2][3][4][5][6][7][8][9][10][11] mediated by KLnCl 4 or LnAl n Cl 3n+3 are corresponding well to the "separation factor-difference of ionic radii" rule. Furthermore, this rule was well proved in the wet separation process for rare earth elements such as solvent extraction and ion exchange methods [24].…”

“…In recent years, a novel promising dry process for the mutual separation of rare earths, which so-called chemical vapor transport reaction (CVT), was studied intensively by Adachi and co-workers [1][2][3][4][5][6][7][8][9][10][11] and Wang and co-workers [12][13][14][15][16][17][18][19][20][21]. They investigated the mutual separation characteristics of rare earth elements from their chloride mixtures, oxide mixtures, concentrates and scraps containing rare earth elements mediated by vapor complexes KLnCl 4 or LnAl n Cl 3n+3 using CVT reaction [1][2][3][4][5][6][7][8][9][10][11][12][13] or stepwise selective chlorination-chemical vapor transport (SC-CVT) reaction [14][15][16][17][18][19][20][21].…”

“…They investigated the mutual separation characteristics of rare earth elements from their chloride mixtures, oxide mixtures, concentrates and scraps containing rare earth elements mediated by vapor complexes KLnCl 4 or LnAl n Cl 3n+3 using CVT reaction [1][2][3][4][5][6][7][8][9][10][11][12][13] or stepwise selective chlorination-chemical vapor transport (SC-CVT) reaction [14][15][16][17][18][19][20][21]. Moreover, the systematic CVT characteristics of pure LnCl 3 (Ln = La-Lu) [4] and SC-CVT characteristics of Ln 2 O 3 (Ln = Sc, Y and La-Lu) [22,23] have been investigated mediated by the vapor complexes KLnCl 4 [22] and LnAl n Cl 3n+3 [4,23]. All the experimental results indicated that the transport efficiency and the main deposition temperature for the lanthanoid elements using the CVT or SC-CVT 0925-8388/$ -see front matter © 2004 Elsevier B.V. All rights reserved.…”

“…All the experimental results indicated that the transport efficiency and the main deposition temperature for the lanthanoid elements using the CVT or SC-CVT 0925-8388/$ -see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2004.06.097 process seems solely depend on the ionic radius of the Ln(III) ion except for Ce [22,23] and Eu [4,23]. That is, the transport efficiency expressed as the total transported amount for LnCl 3 increases with the radius of the Ln(III) ion decreases in the succession from La to Lu, while the main deposition temperature region of LnCl 3 is systematically decreasing in a trend from La to Lu.…”

Mutual separation characteristics for binary mixed oxides Ho2O3–Ln2O3 (Ln = Sc, Y, La, Nd, Sm) using stepwise chlorination-chemical vapor transport reaction mediated by vapor complexes KLnCl4

“…Mutual separation characteristics of rare earth elements by a dry process mediated vapor complexes KLnCl 4 or LnAl n Cl 3n+3 have been investigated intensively from their chloride mixtures, oxide mixtures, concentrates and scraps containing rare earth elements using chemical vapor transport (CVT) reaction or stepwise selective chlorination-chemical vapor transport (SC-CVT) reaction [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. More efficient separation has been observed for oxide mixtures than for chloride mixtures [10,[12][13][14] and using SC-CVT than using CVT reaction [11,15,17,18], and a further improved separation efficiency and total transport yields realized mediated by KCl or KCl-AlCl 3 as complex former instead of only by AlCl 3 as complex former [2,3,10,13,14,20].…”