Mutual Separation Characteristics for Lanthanoid Elements via Gas Phase Complexes with Alkaline Chlorides

Abstract

Mutual separation characteristics of lanthanoid chlorides LnCl3 (Ln = Pr, Nd) using a chemical vapor transporting method via gaseous complexes were investigated. Compared with AlCl3 as the transporting agent, alkaline chlorides can transport more amounts of LnCl3, and enhance the separation efficiency between PrCl3 and NdCl3.

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].…”

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].…”

“…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]. Until now, most of the CVT or SC-CVT mutual separation is limited only for the neighboring rare earth elements except the separation for yttrium which possess the special position in rare earth elements from Y 2 O 3 -Nd 2 O 3 [18], Y 2 O 3 -Sm 2 O 3 [18], Y 2 O 3 -Dy 2 O 3 [14], Y 2 O 3 -Ho 2 O 3 [14] and Y 2 O 3 -Er 2 O 3 [14].…”