The Rare Earths: Their Occurrence, Chemistry, and Technology

Name: The Rare Earths: Their Occurrence, Chemistry, and Technology
Author: Levy, Stanley Isaac

Levy, Stanley Isaac

Rare earths

Bromate.  | |
                       |                               +---------+ +
                       +----------+                    |           |
                       |          |                   Yb, Lu.     Ct?
                       |          |                  Bromates.  Bromate.
                     ~Ho.~      Ho, Yt.
                 Basic Nitrate.

FIG. 9.--SEPARATION OF THE YTTRIUM ELEMENTS]

The more modern methods of separation combine the above processes with
the methods of fractional crystallisation, for which the bromates and
alkylsulphates of these elements are well adapted. The procedure[361]
which experience shows will lead to a fairly rapid separation is roughly
represented in Fig 9. The double sulphates (B), left in solution after
removal of the cerium and part of the terbium group, are transformed
into the bromates, which are separated by fractional crystallisation
into five main fractions. The least soluble portion, fraction 1,
contains the terbium elements with some dysprosium; in the fractionation
of the terbium group by means of the nitrates and double nitrates, the
dysprosium, with some terbium, collects in the final fractions (fraction
6). Fraction 2 contains terbium, dysprosium, holmium, and yttrium as the
bromates; these are converted into the anhydrous chlorides, from which,
by treatment with sodium ethylsulphate in alcoholic solution, the
ethylsulphates are obtained. By fractional crystallisation, dysprosium
may be obtained in a fairly pure condition (fraction 7), the least
soluble part (fraction 6) containing the terbium with some dysprosium.
Holmium and yttrium collect in the most soluble part (fraction 8), from
which pure holmium can be obtained by the method of nitrate fusion.
Fraction 3 contains yttrium and erbium, with small quantities of
dysprosium and holmium; the latter are readily separated by the nitrate
fusion, which will also allow of a fairly complete separation of yttrium
(fraction 9). Fraction 4 contains yttrium and erbium; scandium if
present will also collect here. Erbium can be obtained pure by the
nitrate fusion; the second fraction from this process contains both
yttrium and erbium, and may be further worked up with the fraction of
similar composition (fraction 10) from fraction 3.

  [361] James, _J. Amer. Chem. Soc._ 1912, ~34~, 757.

The mother-liquors from the bromate separation (fraction 5) contain
thulium and the ytterbium elements; the crystallisation is continued,
and allows of complete separation of thulium and ytterbium, and probably
of lutecium, though the most soluble fractions do not seem to have been
fully separated.


THE ERBIUM GROUP

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The Rare Earths: Their Occurrence, Chemistry, and TechnologyLevy, Stanley Isaac

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The Rare Earths: Their Occurrence, Chemistry, and Technology

Levy, Stanley Isaac

Rare earths

Bromate.  | |
                       |                               +---------+ +
                       +----------+                    |           |
                       |          |                   Yb, Lu.     Ct?
                       |          |                  Bromates.  Bromate.
                     ~Ho.~      Ho, Yt.
                 Basic Nitrate.

FIG. 9.--SEPARATION OF THE YTTRIUM ELEMENTS]

The more modern methods of separation combine the above processes with
the methods of fractional crystallisation, for which the bromates and
alkylsulphates of these elements are well adapted. The procedure[361]
which experience shows will lead to a fairly rapid separation is roughly
represented in Fig 9. The double sulphates (B), left in solution after
removal of the cerium and part of the terbium group, are transformed
into the bromates, which are separated by fractional crystallisation
into five main fractions. The least soluble portion, fraction 1,
contains the terbium elements with some dysprosium; in the fractionation
of the terbium group by means of the nitrates and double nitrates, the
dysprosium, with some terbium, collects in the final fractions (fraction
6). Fraction 2 contains terbium, dysprosium, holmium, and yttrium as the
bromates; these are converted into the anhydrous chlorides, from which,
by treatment with sodium ethylsulphate in alcoholic solution, the
ethylsulphates are obtained. By fractional crystallisation, dysprosium
may be obtained in a fairly pure condition (fraction 7), the least
soluble part (fraction 6) containing the terbium with some dysprosium.
Holmium and yttrium collect in the most soluble part (fraction 8), from
which pure holmium can be obtained by the method of nitrate fusion.
Fraction 3 contains yttrium and erbium, with small quantities of
dysprosium and holmium; the latter are readily separated by the nitrate
fusion, which will also allow of a fairly complete separation of yttrium
(fraction 9). Fraction 4 contains yttrium and erbium; scandium if
present will also collect here. Erbium can be obtained pure by the
nitrate fusion; the second fraction from this process contains both
yttrium and erbium, and may be further worked up with the fraction of
similar composition (fraction 10) from fraction 3.

  [361] James, _J. Amer. Chem. Soc._ 1912, ~34~, 757.

The mother-liquors from the bromate separation (fraction 5) contain
thulium and the ytterbium elements; the crystallisation is continued,
and allows of complete separation of thulium and ytterbium, and probably
of lutecium, though the most soluble fractions do not seem to have been
fully separated.


THE ERBIUM GROUP

Public-domain text, read in full here on John Shaqi.

The Rare Earths: Their Occurrence, Chemistry, and Technology

The Rare Earths: Their Occurrence, Chemistry, and Technology

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