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NUCLEAR SCIENCE SERIES

The Radlochemlstry
of Berylhum

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Energy
Commnssuon_

 
COMMITTEE ON NUCLEAR SCIENCE

L. F. CURTISS, Chairman " ROBLEY D. EVANS, Vice Chairman
National Bureau of Standards Massachusetts Institute of Technology

J. A, DeJUREN, Secretary -
-~ Westinghouse Electric Corporation

H.J. CURTIS G. G. MANOV

Brookhaven National Laboratory Tracerleb, Inc.

SAMUEL EPSTEIN W. WAYNE MEINKE

Cealifornia Institute of Technology University of Michigan .

HERBERT GOLDSTEIN - A. H. SNELL

Nuclear Development Corporation of - Osk Rldge National Laboratory
Amerlca - | E. A. UEHLING

H. J. GOMBERG : University of Washington

University of Michigan

_ D. M. VAN PATTER
E. D. KLEMA ' _ Bartol Research Foundation
. Northwestern University :

ROBERT L. PLATZMAN
Argonne Natlonal Laboratory

LIAISON MEMBERS

PAUL C. AEBERSOLD : W. D. URRY

Atomic Energy Commission U. 8. Alr Force
J. HOWARD McMILLEN - _ WILLIAM E. WRIGHT

Natlonal Science Foundation Office of Naval Research

SUBCOMMITTEE ON RADIOCHEMISTRY

W. WAYNE MEINKE, Chairman HAROLD KIRBY

University of Michigan _ Mound Laboratory
GREGORY R. CHOPPIN GEORGE LEDDICOTTE

. Florida State University Oak Ridge Natlonal Laboratory
GEORGE A. COWAN JULIAN NIELSEN
Los Alamos Scientific Laboratory Hanford Laboratories
ARTHUR W. FATRHALL . ELLIS P. STEINBERG
University of Washington : Argonne National Laboratory
JEROME HUDIS PETER C. STEVENSON
Brookhaven National Laboratory Universlty of Callfornia (Livermore)
EARL HYDE LEO YAFFE
University of California (Berkeley) McGlll University

CONSULTANTS

NATHAN BALLOU WILLIAM MARLOW
Naval Radiological Defense Laboratory National Bureau of Standards
JAMES DeVOE

University of Michigan
CHEMISTRY—RADIATION AND RADIOCHFMIST

The Radiochemistry of Beryllium
By A. W. FAIRHALL
Départment of Chemistry
Universily of Washington
Seattle, Washington

May 1960

Subcommittee on Radiochemistry _
National Academy of Sciences —National Research Council

 

Printed in USA. Price $0.75. Available from the Qffice of Technical
Bervices, Department of Commerce, Washington 25, D. C.
FOREWORD

The Subcommittee on Radiochemistry is one of a number of
Subcommittees working under the Commjttee on Nuclear Science
within the National Academy of Sclences-Rationzl Research Council.
Its members represent government, industrial, and university
laboretories in the areas of nuclear chemistry and analyticael
chemistry.

The Subcommittee has concerned itself with those areas
of nuclear science which involve the chemist, such as the
collection and distribution of radiochemical procedures, the
establishment of speclifications for radiochemically pure reagents,
the problems of stockpiling uncontaminated materials, the avalla-
bllity of cyclotron time for service irradiations, the place of
radiochemistry in the undergraduate college program, etc.

This series of monographs has grown out of the need for
up~-to-date compilations of radiochemical information and pro-
cedures. The Subcommittee has endeavored to present a series
which will be of maximum use to the working scientist and which
contelns the latest available information. Each monograph
collects in one volume the pertinent information required for
radiochemical work with an individual element or a group of
closely related elements,

An expert in the radiochemistry of the particular element
has written the monograph, following e standard format developed
by the Subcommittee., The Atomic Energy Commission has sponsored
the printing of the series.

The Subcommittee 1s confident these publications will be
useful not only to the radiochemist but alsc to the research
worker in other fields such as physics, biochemistry or medicine
who wishes to use radicchemical techniques to solve a specific
problem.

W. Wayne Meinke, Chairman
Subcommittee on Radiochemistry

iid
I.

II.

II1.

VI.

CONTENTS

GENERAL REVIEWS OF THE INORGANIC AND ANALYTICAL
CHEMISTRY OF BERYLLIUM

ISOTOPES OF BERYLLIUM

REVIEW OF BERYLLIUM CHEMISTRY OF INTEREST TO
RADIOCHEMISTS '

General Cf;nsiderations

Complex Ions of Beryllium

Chelate Complexes of Beryllium

Soluble Compounds of Beryllium

Insoluble Compounds of Beryllium

Solvent Extraction of Beryllium Compounds

-~ O N W N R

Ion Exchange Behavior of Beryllium
PROCEDURES FOR DISSOLVING SAMPLES CONTAINING .
COMPOUNDS OF BERYLLIUM

COUNTING TECHNIQUES FOR USE WITH ISOTOPES OF
BERYLLIUM

COLLECTION OF DETAILED RADIOCH.EMICAL PROCEDURES
FOR BERYLLIUM

© @ W e W

10
16

21

22

28
The Radiochemistry of Beryllium™*

A. W. FATRHALL
Department of Chemistry
University of Washington, Seattle, Washington
May 41960

I. GENERAL REVIEWS OF THE INORGANIC AND ANALYTICAI, CHEMISTRY
OF BERYLLIUM ' -

"Beryllium", pp 197-218, Vol. I. of "The Chemical Elements and Their
Compounds', N.V. Sidgwick, Oxford University Press, London, 1950.

"Beryllium', pp 204-248, Vol. IV of "A Comprehensive Treatise on
Inorganic and Theoretical Chemistry', J. W. Mellor, Longmans, Green
and Co., London, 1923.

Gmelin's Handbuch der A.norgahischen Chemie , System Nr. 26, 8th Edition,
- Verlag Chemie G.m.b.H., Berlin, 1930.

Chapter 32, pp 516-523, "Applied Inorganic Analysis', W. F. Hillebrand,
G.E.F. Lundell, H. A. Bright and J. I. Hoffman, 2nd edition, John
Wiley and Sons, Inc., New York (1953),

"Beryllium", pp 137-148, Vol. I of ''Scott's Standard Methods of Chemical
Analysis", N. H. Furman, editor, fifth edition, D. Van Nostrand Co.,
Inc., New York, 1939.

L. W. Neidrach, A, M. Mitchell and C. J. Rodden, pp 350-359, "Analyti-
cal Chemistry of the Manhattan Project'', C. J. Rodden, editor-in-
chief, McGraw-Hill Book Co., Inc., New York, 1950.

"Non-ferrous Metallurgical Analysis. A Review.' G.W.C. Milner,
Analyst 81, 619 (1956). |

* Thie report was prepared at the request of the Subcommittee on
Radiochemistry of the Committee on Nuclear Science of the National
Research Council as a contribution to a proposed master file on the
radiochemistry of the elements.
. ISOTOPES OF BERYLLIUM

Only four isotopes of beryllium are known to exist, those having
mass numbers 7, 8, 9 and 10. One of these, BeB, ise completely
unstable, breaking up into two alpha parficles in a time less than
10_15 sec. A short-lived isotope of mass 6 has been repor‘l:ed:l but
ite existence is doubtful. Of the remaining three, Be’ is the only
one which is stable, and constitutes the element. Beryllium is not
an abundant element, although its principal mineral, beryl, 3 BeO-
Ale 3" 6 SiOZ, is rather wide spread in occurrence. T_l}e average
befy]lium content of rocksz is only about 3 ppm, and sea water3
contains only about 5 x 10713 g/ml of the element.

. The isotopes of masses 7 and 410 are of interest in that they are

both relatively long-lived nuclides. B37 has a half-life of close to
54 day4, decaying by K-electron capture to stable LiT. Of these
decays, 12% go to a 0.477 Mev excited state of Li7 and the remainder
go to the ground state. 2 The only detectable radiation therefore is
the 0.477 Mev y ray, the x-rays of Li being much too soff to be
detectable by present techniques. The branching ratio of 12% to the
excited state of L17 is uncertain by 5 - 10 per cent,

Because of its rather low mass and convenient half-life, Be7 is
a nuclide of some interest in the study of nuclear reactions produced
artificially in the laboratory. It arises as a spallation producte'“‘10
in the nficlear reactions induced at high energies, and its production
11, 12 Pro-
duction of B_e7 by cosmic ray bombardment of the atmosphere has also

been observed. 13-15

at lower energies in light elements is of some interest.

The heaviest isotope of beryllium, Beio, ie quite long lived, with

a half-life of 2.5 x 108y. ‘n decays by p~ emission to the ground

state of stable Bio, and in keeping with the long half-life and
consequent slow build-up to detectable intensities, the production

of Be:10 in nuclear reactions in the laboratory is not likely to be
-gtudied radio —chemica_'l.ly; ' Howevef, Bei('J is produced as a spéllation

6,17
- product of cosmic ray action on the atmosphere:l ! 17 and on meteorites, 18
so that its occurrence in nature is of considerable interest to the

geochemist.
II. REVIEW OF BERYLLIUM CHEMISTRY OF INTEREST TO
RADIOCHEMISTS

1. General Considerations

In any radiochemical separation of a particular element the chemical
procedures which are used are governed in part by the amount of the
element which is present in the sample which is being analyzed. Iso-
topic carrier, in amounts of the order of milligrama, are often added
to the sample to facilitate the separations and to determine the chem-
ical recovery of the radioactive species. In the case of beryllium the
amount of beryllium carrier which. is to be added to the sample is
governed by which of the two radioisotopes is of interest: Be7 can
tolerate relatively large amounts of carrier without interfering with
the subsequent counting efficiency, whereas samples for counting Be10
should be as weéightless as possible. Fortunately radiochemical
procedures for beryllium are available which efficiently will isolate
amounts of beryllium r'angi.ng from sub-microgram up to macro -
amounts. '

In performing chemical separations with sensible quantities of
beryllium present it must be born in mind that beryllium is a very
toxic element. Care should be exercised to avoid ingestion of beryllium
through the mouth via pipettes or by inhalation of dust or volaetile

 

 

beryllium compounds. If beryllium —cofita.i.ning solutions are spilled
on the skin they should be rinsed off at once.

Beryllium is the lightest member of the group II elements. In
keeping with its position in the periodic chart it has only one oxidation
number, + 2. It is a very good example of the rule that the first member
of a group shows a strong chemical resemblance to the second member
of the next higher group: in its chemical behavior beryllium more
closely resembles aluminum than it does othef members of the group II
elements. |

Because of the electropositive nature of beryllium, and the existence
of only one oxidation number for the ion, exchange between carrier and
tracer species presents no problem so long as the Sample cbnta.inin.g them
is complefeiy homogeneous. The strong tenciency of bery]lium to o
hydrolyse and form colloidal aggrég'atgls. above pH 5 requires El:hat

carrier-tracer exchange be carried out in fairly acid solution.
- Many of the chemical proper‘l:iéé of beryllium which are important
in its radiochemical separations are associated with its ability to
form complex ions. These complexes will be treated first,

2. Complex Ions of Beryllium

Because of its _s:fiall size and its double charge, the beryllium ion
has a strong tendency toward the formation of complexes. Thus the
simple salte uniformly have 4 molecules of water of crystallization
per beryllium atom, and the hydration of the Be'™ ion forms a basis
for understanding the strong tendency toward hydrolysis and the
amphoteric properties of this species. Stability constants for several
beryllium complexes are given in Table 1.

The strong tendency of Be'™ ion toward complex formation shows
up in a rather peculiar way by its power to dissolve beryllium oxide.
The aqueous solution of any soluble salt of beryllium can dissolve up
to several molecular proportions of béry_llium oxide or hydroxide.
The reason for this is apparently the tendency to form the complex ion

Be(OBe)f , Where BeO molecules have replaced HZO molecules in

the aquo complex.

Table I. Stability Constants for Beryllium Chelates

 

Chelating Agent log K, log K, log K, " Reference
EDTA >3 @ L | 2
acetylacetdne 8.2 7.7 - | 2
9.2 7.8 - 48
7.8 6.7 o 49
oxalic acid ' 4..0 _ ' _ | 2
phosphoric acid 2,54 1.8 | 1.4 L2

The complex formed between Be++ and CZO 4 = , i8 of some interest
inasmuch as it is the only oxalate of a divalent metal which is freely
soluble in water. It is a good illustration of the difference in chemical

behavior of beryllium from that of the remainder of the group II
elements. The low degree of ionization of the compound is evidence
that it exists as a chelate complex.

The complex formed between beryllium and fluoride ion is worth
noting. Excess fluoride ion forms the complex anion BeF =, which
resembles very closely the sulfate anion. Thus BaBeF4 forms an
insoluble precipitate and finds a use in the final precipitation of beryllium
in radiochemical analyses. The soluble nature of sodium fluorobgryllate
can be used to advantage where mineral specimens are fused with
fluorides to render them soluble. 19 The complex is a fairly sirong
one, but may be completely destroyed by the addition of excess H3BO3.

Beryllium ion is soluble in 10% (N’H4)ZCO3 solution at pH 8. 5-9,
presumnably because of the formation of a complex carbonate anion.

This property of beryllium has been used in an ion exchange technique
for the separation of beryllium from copper and nickel. 20

The f_orma.tion of a BeHZPO 4 complex which limits the phosphatg

content of solutions which are to be used in certain cation exchange

2
separations has been reported.

3. Chelate Complexes of Beryllium

Bery]liurfi forms nurnerous chelate complexes with a variety of
complexing agents. These complexes may be divided into two groups
according to whether they are neutral or negatively charged.

Neutral complexes are derived either from hydroxy-keto compounds,
i.e. p-keto-enois, B-keto-esters and hydroxyquinones, or are a special
clags of covalent derivatives of carboxylic acids. A large number
of hydroxy -keto compounds have been studied as chelating agents in
the colorimetric determination of trace amounts of beryllium. 21 For
details of these procedures the original literature should be consulted.

There are four chelating agents which deserve special mention
because of the important roles which they play in radiochemical separa-
tions of beryllium. The first of these which will be mentioned is
ethylenediamminetetraacetic acid (abbreviated EDTA), and for the reason
that it forms a much stronger complex with many metals than it does
with beryllium. Table I lisfs stability constants for a number of metal
ions with EDTA. The value of ~ 3.8 for beryllium is sufficiently

smaller than those of other common metal ions that _sever_al useful
separations may be carried out using EDTA: to prevent interference from
other metal species. For example, beryliium hydroxide may be precipitated
with ammonia in the presence of aluminum, without the latter precipitating,
if excess EDTA is present. Other examples of similar applications will
be cited later.

A second very useful chelating agent for berylium is acetylacetone.
The chelate compound beryllium acetylacetonate, Be(C 5H7OZ)2
melting (108°) volatile (b.p. 270°) golid, ineoluble in water but soluble"

is a low
in organic solvents. This chelate compound forms the basis for a

Table II, Formation Constants of Metal - EDTA Compleces 2"

Cation | log K Cation log K
Vanadium (IIT) 25.9 Europium - 17. 135
Iron (III) 25,1 _ Samarium 17.14
Indium 24,95 Neodymium 16,61
Thorium 23.2 Zine 16,50
Scandium 23.1 Cadmium 16, 46
Mercury 21,80 Praseodymium 16, 40
Gallium 20.27 Cobalt” 16, 34
Lutecium 19.83 Aluminum 16.13
Ytterbium 19.51 Cerium (III) 15.98
Thulium 19. 32 Lanthanum 15,50
Erbium  18.85 Iron (II) 14,3
Copper 18.80 Manganese _1.4. 04
Vanadyl 18, 77 Vanadium (II) 12. 70
Nickel 18. 62 Calcium 10.96
Dysprosium - 18.30 Hydrogen 10. 22
~ Yttrium 18. 09 . Magnesium 8.69
Lead 18.04  Stroptium 8. 63
Terbium 17.93 Barium - 17,76
Gadolinium 17.37 - Beryllium 3.8
M7 ¢ vy r e my™t K = —M%
M Y

2 In solutions of ionic strength 0.41. Data from reference 22, except

for Beryllium, which is from reference 2.
solvent extraction procedure for amounts of beryllium as small as the
carrier-free tracer (see part III-6), Owing to the volatility of the
chelate compound, care must be exercised in reducing solutions of
tracer beryllium to dryness .wher'e acetylacetone has been used, in
order to avoid lose of the tracer. 23

A third chelating agent which is useful for the isolation of beryllium
is the compound thenoyltrifluoroacetone (T'TA). The complex with
beryllium is slow to form and to decompose, a property which makes
possgible a solvent-extraction separation of beryllium from a number
of other cations. 24 The non-volatility of this complex is an advantage
over acetylacetone where tracer amounts of beryllium are concerned.

The fourth chelating agent of significance to beryllium separations
is acetic acid. Beryllium is almost unique in form.:inlg a series of
complex compounds with carboxylic acids, of the general formula
Be ,O (O-CO-R),. These compounds are non-ionized, soluble in organic
solvents, and volatile. The best known of these ig the acetate, 'basic'
beryllium acetate, which is formed by treating beryllium hydroxide
with acetic acid or acetic anhydride. It is generally employed for
solvent extraction of beryllium in radiochemical analyses, although the
stability and volatility of the complex (b.p. 330°) permits its isola-
tlon by distillation.

The second group of chelate complexes of beryllium are those
which possess a negative charge. Complexes of this type have been
prepared with a number of complexing anions including oxalate, malonate,
citrate, Salicylate and sulfate. The complex formed with oxalate has
been used in the back-extraction of beryllium acetylacetone from the
organic phase in a solvent extraction procedure for beryllium. 23
Complex formation with citrate has been demonstrated and used in the
ion exchange separation of the group II metals. 24 The salicylate
analogues sulfosalicylate and gentisic acid (2, 5-dihydroxylbenzoic acid)
have been used as complexing agents in an ion exchange procedure for
separation of berylliumzs and for the spectrophotometric determination
of beryllium. 26

Details of the solvent extractiion and ion exchange procedures
involving chelate complexes of beryllium will be outlined in parts II1-6
and -7. '
4. Soluble Compounds of Beryllium-

Beryllium hydroxide is a weak base and therefore solutions of its
salts are exiensively hydrolysed, forming ions like Be(OH)+ and
probably also colloids of the form (BeO)x Be++. Salts of such weak
acids as HCN, HZS and HZCO3 are almost completely hydrolysed in
water.. The hydrolysis of beryllium solutions leads to the absorption of
beryllium onto the walls of the containing vessel. Figure 1 shows the
percentage adsorption of Be7 from carrier-free solutions in
0.1 M NaCl buffered with 0. 004 M NaAc as a function of pH. e The pH
was varied by addition of HCl or NaOH. Absorptions as high as 20%

on glass containers were observed at the higher pH's.

 

 

 

 

;\3 ¥ S T ¥ ¥
Z 40}
3 fl
-
a 3o} ]
8 .
n 20} GLASS 1
a /
< S
R . POLYETHYLENE *
i | ..—-"
g 0 i - 1 1 1

3 4 5 6 ® 9

pH

Figure 1. Adsorption of beryllium on the walls of polyethylene
and glass vessels as a function of the pH of the

solution.- Data of reference 2.

Beryllium salts of strong mineral acids such as HNOB, HC1, HBr,
HZSO & HCI10O 4 €ic are all quite soluble in water and the salts themselves
are usually hygroscopic. The strong tendency of beryllium to form
complex ions is shown by the fact that these salts always cry'stallize
from aqueous solution with at least 4 molecules of water per atom of
beryllium, corresponding to the tetraaquo complex.

Soluble complex ions with F_, oxalate, citrate, etc. have already
been mentioned (parts III-2 and -3).

The action of strong bases such as NaOH or KOH first precipitate
insoluble Be(OH)Z-aq, but addition of excess base causes the precipitate
to redissolve. At room temperature the solubility of freshly precipi-
tated beryllium hydroxide in 0. 39 N, 0.65 N and 1.99 N NaOH is
reported to be 0, 06, 0.144 and 0. 66 moles of BE(OH)Z per liter, 21
The solution, however, is unstable. On long standing, or on boiling,
beryllium is reprecipitated as a dense crystalline precipitate corres-
ponding to the formula 'Be(OH)Z. The amphoteric nature of beryllium
hydroxide is a very useful property in radiochemical separations, but
whenever a strong base is used to dissolve beryllium from a mixture
of insoluble, non-amphoteric hydroxides the mixture should not be
subjected to prolonged boiling to effect solution of the beryllium lest

the opposite of the desired result be obtained.

5. Insoluble Compounds of Beryllium

The most important insoluble compound of beryllium, so far as
radiochemical separations is concerned, is the hydroxide. It is
precipitéted from aqueous solution by dilute base. Because of the
amphoteric nature of the freshly precipitated hydroxide, the best
precipitant for beryllium is ammonium hydroxide buffered with NH 4+ ion.
The precipitate of beryllium, which begins to appear at around pH 5,
is essentially insoluble in an excess of this reagent. Precipitation
of beryllium at the methyl red end point (pH ~6) has been recommended. 28

Precipitation of dense, unhydrated Be(OH)Z from boiling alkaline
solution has been mentioned above in connection with the amphoteric
properties of beryllium. A somewhat similar result is obtained if the
complex carbonate of beryllium in ammonium carbonate solution is
‘boiled. In this case there is obtained a white, granular pre-c-ipitate of
basic beryllium carbonate of somewhat indefinite composifion.

Addition of sodiuni bicarbonate solution to a solution of beryllium also
precipitates basic beryllium carbonate. Ignition of the hydroxides or
the basic beryllium carbonate results in beryllium oxide.

Because of the weakneas of the acid, and the consequent strong
tendency to hydrolysis of the resulting compounds, the phosphates of
beryllium have a rather complicated chemistry. At lower pH's soluble
compounds may be obtained, while at higher pH's Ingoluble precipitates
of gelatinous nature, and therefore difficult to identify, are formed.
However, an insoluble crystalline precipitate approximating NH 4BePO 4
may be obtained by adding (NH 4:)Z]EIPO 4 to beryllium solutions at pH 5. 5?9

Ignition of the precipitate results in Be ZPZOT This plrocedure is
therefore useful in obtaining beryllium in a dense form of known
composition.

Another method for precipitating beryllium which has some
advantages over the others involves formation of the BeF 4= complex
anion by addition of excess F ion, followed by the addition of excess
Ba++ ion. The solution should be aci-dj_t‘-ied and only a slight excess
of Ba++ ion should be used in order to prevent the precipitation of
BaFZ. The resultant precipitate of insoluble BaBeF 4 is fine-grained
and very difficult to filter through the usual types of dense filter
paper. Digestion of the precipitate for 10 minutes prior to filtra-
tion helps somewhat, but the filtration problem can be overcome
completely through the use of RA -type Mflliporg filters. The compact,
dense, and anhydrous precipitate does not require ig’nitidn as do the
others mentioned above. This is a distinct advantage in eliminating
the health hazard associated with the transfer of ignited beryllium
precipitates, which tend to "dust'. The BaBeF 4 Precipitate is much
more readily redissolved than ignited BeO, being easily dissolved in
a mixture of H3BO3 and HNO3. This is a useful property where
further chemical processing is needed to remove unwanted radioactive
contaminants from a beryllium sample.

Ber:yllium's strong tendency toward hydrolysis, and the insolubility
of its hydroxide in near neutral solutions, means that beryllium will
tend to co-separate on precipitates when the solution is not at least
moderately acid. 29 Almost any precipitate which is forn%ed in a solution
containing beryllium at pH~7 will co-precipitate the beryllium to some
extent. Particularly useful in this respect _:fi-e gelatinous hydroxides
such as those of aluminum and iron. Using Fe(OH), as the co- '
precipitant for beryllium allows the beryllium to be recovered from the
precipitate by treatment with cold NaOH solution, or by other means.

6. Solvent Extraction. of Beryllium Compounds
The chelate complexes of beryllium with acetylacetone, TTA, and

acetic acid, which were mentioned in part III-3 above, lend themselves

o . :
Obtainable from the Millipore Filter Corporation, Watertown 72,

Massachusetts.

10
to very useful solvent extraction procedures for beryllium. These will
be given in detail below,

Ac e1_:zla.cetone .

By shaking or stirring aqueous solutions containing beryllium at
pH 4.5 - 8 with acetylacetone a chelate complex is formed which is
soluble in organic solvents. Either pure acetylacetone, a solution
of acetylacetone in benzene or CCl4 may be used. The use of a small
quantity of pure acetylacetone hastens the formation of the chelate
complex, after which the complex may be extracted into benzene or
other suitable solvent. By stirring a solution at pH 4.5, containing
about 1 microgram of beryllium with 4 ml of acetylacetone for
5 minutes, and then adding 20 ml of benzene and stirring for 20 minutes
longer, Toribara and Chen found that essentially 100% of the

29 Bolomey and Broido?'3

beryllium is transferred to the 6rga.nic phase.
shook 25 ml of 10% acetylacetone in benzene with 25 m] of a solution
containing carrier-free beryllium tracer at pH 6 for 2 hours and

. found that all but a trace of the activity was exiracted into the

organic phase.

A great many other metal ione likewige form chelates with acetyl-
acetone, and under the conditions described above many of them would
also be extracted. The use of EDTA makes the extraction more specific
for beryllium. Alimarin and G:lba.lo30 studied the extraction of beryllium
acetylacetonate into CCl 47 CHC1 3 butyl alcohol and isoamyl alcohol
containing acetylacetone from aqueous solutions containing EDTA
and Al, Fe, and Cr, and the divalent ions of Co, Fe, Ni, Mn, Zn, Cd,
Pb, Cu, Ca and Mg. When excess EDTA was present only beryllium was
extracted into the organic phase. CCl-4 proved to be the best of the
solvents which were studied. In strongly ammoniacal solution aluminum
and iron acetylacetonates could also be extracted,

The organic phase containing beryllium acetylacetonate may be
washed with acidified water to remove unwanted impurities without
the loss of appreciable amounts of bery].lium23. About 2 drops of
0.1 N HC1 to 25 ml of water makes a satisfactory wash solution for
this purpose.

The beryllium acetylacetonate complex may be decomposed and
the beryllium back extracted into water by shaking the organic phase

11
coritaining the chelate complex with equal volumes of either 10%
oxalic acid or 6 N HCl. Bolomey and Broido23 report that 96% of
tracer beryllium is back extracted in 2 hours under these conditions.
Toribara and Chen29 report that 15 minutes stirring of the organic
phase with 5 N HCI] is sufficient to transfer the beryllium to the
aqueous phase. Because of the volatility of carrier-free beryllium

acetylacetonate, acetylacetone which dissolves in the acid used to

 

100
80
60

ao |

PERCENT EXTRACTION

 

20

 

 

i 1 i L

60 120 180 240
TIME (MINUTES}

Figure 2. Rate of extraction of Be by 0. 04 M TTA in benzene at
different pH values. Data of Bolomey and Wish,

reference 31,

back-extract the beryllium should be extracted from the aqueous phase

by washing the latter with one or more portions of fresh benzene. The

aqueous phase may then be evaporated to dryness under a heat lamp.
If oxalic acid is used to accomplish the back -extraction of beryllium
it may be sublimed under a heat lamp without loss of activity. 23 With

beryllium carrier present the loss of beryllium through volatilization

during evaporation of the aqueous phase does not appear to be a problem.

12
a-Thenoylirifluoroacetetone:

 

Thenoyltrifluoroacetone (TTA) is a useful chelating agent for

many metals, including beryllium. Bolomey and Wish31 have inves~-

 

 

 

 

 

 

 

 

++
100 - Cu™™ pH 3.40 |
Al pH 5.5
&
= 8o} -
-
L
< X i
@
-
X 60t —
L
5 i 4
S
& 40H -
w
& |
Fell pH 6.38
20K ~
s Al pH 3.4 .
60 (20 80 240

TIME (MINUTES)
Figure 3. Rate of extraction of various metallic ions by 0.041 M TTA
in benzene at different pH values, Data of Bolomey and

Wish, reference 31.

tigated the conditions under which beryllium may be separated from
a number of other metal cations using this reagent. The complex
is rather slow to form and to decompose. In Figure 2 is shown the
rate of extraction of beryllium by 0.04 M TTA in benzene at different
pH's. The optimum pH for the extraction seems to be about 7, with
extraction of beryllium being essentially complete in about 3 hours.
The extraction of iron (III), aluminum and copper by 0.01 M TTA
in benzene at different pH values is shown in Figure 3. Evidently
aluminum is also extracted quite favorably at pH 7, but the extraction
of iron is relatively much less favorable at the higher pH.

The back-extraction of TTA complexes of Be, Al, Ca, Fe, Zn,

Sr and Y from benzene solution made 0.04 M in TTA by concentrated

13
 

8

PERCENT EXTRACTION
8 &

 

 

 

 

] 1 l 1 1
- 0 o 20 30 40

TIME (HOURS)

 

Figure 4. Back extractions of several metallic ions with
concentrated hydrochloric acid. Data of Bolomey and

Wish, reference 31.

hydrochloric acid is shown in Figure 4. Back extraction of Ca, Fe,
Zn, Sr and Y is complete in 15 minutes. Aluminum requires é hours,
and beryllium at least 80 hours, for ''complete' back-extraction.
However, the use of 2 parts concentrated formic acid to 1 part
concentrated HC1 accomplishes the back-extraction of beryllium in

a matter of a few minutes (cf. Section VI, Procedure 12).

The solvent extraction method using TTA works equally well for
tracer or micro amounts of beryllium. For tracer concentrations of
beryllium T'TA has the advantage over acetylacetone that there is no
loss of beryllium through volatilization of the beryllium - TTA complex.

Acetic acid.

When freshly precipitated beryllium hydroxide is evaporated slowly
to dryness several times with glacial acetic acid3z, or wfien beryllium
acetate is heated to 200° 014, there is formed the chelate compound
Be4O(O-CO-CH3)6, '"bagic'' beryllium acetate. It is a crystalline

substance ihsoluble in cold water, but readily soluble in most common

14
organic solvents except alcohol and ether. Chlorofarm ig the solvent
most commonly employed. The solution of ''basic' beryllium acetate
in chloroform is remarkably stable and may be washed free of other
cations by extracting with water acidified with HC1 or with water alone.
Recovery of beryllium from the chloroform solution may be accomplished
by extraction with reagent II‘:[NO3 or by evaporation of the chloroform
followed by decomposition of the basic beryllium acetate by heating with
concentrated HN03.

The preparation of basic beryllium acetate i85 somewhat time-
consuming., This disadvantage is offset somewhat by the specificity of '
the procedure for beryllium.

7. Ion Exchange Behavior of Beryllium

The strong tendency of beryllium toward complex formation makes
possible ite separation by a variety of ion exchange techniques. These

are summarized in Table III and discussed in detail below.

Cation Exchange Re sins:

 

Separation of beryllium from other cation species by cation exchange
may be accomplished in Beveral ways. Beryllium is strongly absorbed
on the cation exchange resin Dowex 50 at pH 6 - 8, presumably owing to
colloid formationz. At lower pH's beryllium will pass slowly through
a cation exchange resin solumn>>. Ehmann and I«.’.ohr:r:ua'a.n28 passed a
1.1 M HCI1 solution containing Be and Al through a Dowex 50 column, a.nd
followed it with 1.4 M HCl. At a flow rate of 1 resin volume of eluent
per 25 minutes the beryllium was completely eluted with é or 7 resin
volumes of 1.4 M HCl. Under these conditions aluminum begins to elute
only after 12 to 15 resin volumes of 1.1 M HC! have been passed through
the column.

Milton and Gru.mmi’cl:34 have used 1.5 M HC1 as eluting agent and
Dowex 50 resin to effect a separation of beryllium from the cther
members of the alkaline earth family. Their results are shown in
Figure 5. |

Hond:s:.35 and Kald.ha.na36 have linvestiga.ted the elution of beryllium
from Dowex 50 reain by the usge of dilute Ca or Mg solutions. These

cations -displace Le from the column, which therefore passes through,

16
but cations such as Al which are more strongly held than the alkaline
earths are retained by the resin. | |
Complexfi.ng agents, for either unwanted cations or beryllium, have
' been used in the sepa_ration.of beryllium by cation exchange resins.

Merrill,Honda and .A.I'J:Lold2 have studied the effect of various complexing

Table ITI. Ion Exchange Methods for the Separation of Beryllium

Cation Exchange

Resin Form Eluting Agent Ions Eluted Ions Retained Reference
HR ca 1M HC1 Be Al, Mg,Ca,Sr,Ba 28, 34, 35
HR 0.05MCaor Mg Be 35, 36
HR 0.4 M ozalic acid AL Fe”', U0, Be 2
Th, others
HR oxalic acid Al, Fe Be 37
- pH 4.4-5
NH R 0.55 M Amm.lac. Be other alk.earths 34
pH 5
NH 4R. 10%(NH 4)ZCO3 Be Cu, Ni | 20
pH 8.5-9
3+ ++
NaR EDTA,pH 3.5-4.0 Al Fe™ , Mn Be, alk.earths 2, 38, 39
' heavy metals,
others
NH R 0. 35 M acetate Be Al, alk,earths, 2
U, others
NaR. acetylacetone Be’ Al, alk, earths 2
PH 5 U, others
N".E[4R 0.02 M sulfosali- Be Cu, U, Ca 25
cylic acid pH 3. 5-
4.5
Anion Exchange
RC 204 0.4 M oxalic acid Be Al 28
0.15 M HC1
RCit i Mamm.cit.pH 8 Be other alk.earths 24
RC1 various conc.HC1 Be many transition 40-42
elements
RC1 13 M LiCl alk. metals, Be 43
Mg

16
INTERSTITIAL COLUMN VOLUMES
2 3 4 6810 20 30 40 €0 80100

I III—II'T I —l_llfllll

 

5
o

Ca

NO Ba
TO
650 ml

CONCENTRATION OF SOLUTE (mg/ml)
o
{

 

 

 

o

L1t 1 1
20 3040 6060100 200 300400 600

ELUATE VOLUME (mi)

 

0
@k
5

Figure 5. The separation of beryllium, magnesium, calcium,
~ and strontium by cation exchange using 1.5 M
hydrochloric acid eluant. Dowex 50 column 1.1
x 8 cm, flow rate 1.0 ml/min, T ~ 60° C. Data

of Milton and Grummitt, reference 34.

agents on the uptake of beryllium by Dowex 50 resin. Be7 was used as
a tracer in these experiments which were conducted at room temperature,

23 - 25° C. They define the distribution coefficient of Be, Kd’ to be

Be7 adsorbed / g resin

 

Ky = 7
Be remaining / ml solution

at equilibrium. For purposes of normalization they also define the

distribution coefficient, D, to be

Be++ adsorbed /g resin
Be7 remaining /ml solution

 

D=

measured in the absence of complexing agents.

In0.1 M Na+, and with the resin in the sodium form, D was |
measured to be 700 for 200-400 mesh resin and 830 for 50-100 mesh
resin. In 0.1 M H+, and with the resin in the hydrogen form, D was

17
measured to be 1870 for 50-100 mesh resin. The value of D was found
to vary with the concentration, C, of the monovalent cation in the,solution,
and in the neighborhood of the concentrations which were used D varied

K
as _1 . Values of the quantity _ d are shown in Figure 6 plotted
2 D

against the concentration of complexing agenti for several cases.

Stability constants were calculated for the several complexes from
these cation exchange data and are given in Table I, page 4.

Because certain unwanted cations may form much sironger complexes
than does beryllium, the use of complexing agents such as EDTA or
oxalate can be quite efiective in isolating beryllium from a mixture of

 

 

 

 

 

1 1 I 1 1 I I I 1 I 1 !
.00 ]
0.10 —
Xd
D
0.01 ]
0.001 1 1 1 i
" 4 3
CONCENTRATION OF COMPLEXING AGENT
O« EDTA(Y*~},0.08M Nat-NaR D« OXALATE (aA=),0.1 M. Né"NaR
X « ACETYLACETONE {A™),0.1M + = PHOSPHORIC ACID (A™) 0.C3 M H*-HR

.
Na™= Na R . ® = H PO~ (A), 0.IM Ne'-NaR
N = OXALIC ACID(A™),0.IM H'-HR

A= OXALIC ACID(K"),0,IM Na'~Nag R

Figure 6. Uptake of beryllium by Dowex 50 resin from
solutions containing various complexing agents,

Data of Merrill, Honda, and Arnold, reference 2.

18
cations. EDTA is especially useful in this respect, particularly in the
separation of beryllium from iron and aluminum. Table IV showe the
small uptake of aluminum by Dowex 50 when excess EDTA is present. 2
Using Amberlite IR-120 resin in the sodium form Nadkarni, Varde and
Athavale 38 found that from solutions containing excess NaZHZ EDTA

at pH 3.5 beryllium was absorbed by the resin while aluminum, calcium
and iron passed through the column. If HZOZ was present titanium also
passed through the column unabsorbed by the resin.

Oxalic acid is useful for the separation of beryllium from such ions
as Fe+3, A1+3, U02+2, and Th+4. Oxalic acid, 0.4 M solution, may be
used to elute these ions while beryllium is retained on the column. 2
Ryabchikov and Buk.htiarov37 report the separation of beryllium from iron
and aluminum by the use of oxalate at pH 4.4, Iron and aluminum pass
through as complex ions while beryllium is retained on the column.

The separation of beryllium from magnesium and the other alkaline

Table IV. Uptake of Aluminum by Dowex 50 from Solutions
Containing Excess EDTA

Volume of solu- pH before pH after Al absorbed
tion pessed® passing passing (mmole /g resin)
50 2,79 : -- 0.19
30 _ 3.40 3.24 0.007
30 3,62 3.78 0.003

50 3.52 3.64 0.0026

8 sample solution: 0.22 M Na' + 0.4 M AIY  + 0.041 M excess EDTA
+S0,7; CaCO, added to adjust pH. Data of Merrill, Honda, and
Arnold, reference 2.

earths by means of ammonium lactate hag been deacribed by Milton and
Grummitt. 34 Using 0.55 M ammonium lactate at pH 5 as the eluant, a
flow rate of 1 ml/min., and a Dowex 50 column maintained at a temper-
ature of 78° C, beryllium was eluted from a 1.1 x 8 cm column in less
than 2 interstitial column volumes. This was considerably in advance

of magnesium, which began to elute at around 2.5 interstitial column

volumes,

19
The use of palicylate analogs for selective elution of beryllium
adsorbed on a Dowex 50 reain column has been reported by Schubert,
Lindenbaum and Westfall. ?'_2' Using 0.02 - 0,410 M sulfosalicylic acid at

pH 3.5 - 4.5 beryllium is selectively eluted while Cu.H-,l uo t and Ca++

2
iong remain firmly on the column. If iron is also adsorbed on the

column it can be eluted before the beryllium with 0.4 M sulfosalicylic -
acid at pH 2. 1,

When 0.1 M gentisic acid at pH 6, 0 is used to elute a Dowex 50
column (H - form) containing adsorbed Ca++ and Be++ ions the beryllium
- comes off in a sharp band, beginning when the pH of the effluent reaches
1.9, reaching a maximum at pH 2.-74 and complete when the effluent
reaches pH 5. 60. 25 Under these conditions calcium is still retained on
the column.

Starting with 150 ml of solution containing 1.1 g of Ca.Clz, 5 pg of
Be, and 0.1 M in sulfosalicylic acid at pH 4.5, these authors passed the
solution through a column containing 15 g of air —dried Dowex 50 resin
which had been equilibrated with 0.4 M sulfosalicylic acid at pH 4. 5.
Beryllium pasaed completely through the column with the aid of 70 ml
of wash solution (0.1 M sulfosalicylic acid at pH 4. 5) while calcium was
completely adsorbed. | '

Rapid elution of beryllium adsorbed on a cation exchange resin
which has been washed free of unwanted cations may be accomplished
by sirong (> 3 M) HCI, 33, 38, 44 or by a solution of 0.5 M NaAc and
1M H.Acz. In the latter case 0.5 - 1,5 column volumes of effluent
contain all the beryllium, which may be recovered as Be(OH)2 by
adding NH 4OH'?'.

Anjon Exchange Resing:

The use of anion exchange resins in the separation of metal cations

 

implies the formation of negatively charged complex ions, either of the
depired element to be separated, or of unwanted impurities. As an
example of the latter, in hydrochloric acid solution beryllium does nof
form a complex with chloride ion of sufficient strength to be absorbed
on Dowex I resin. 45 A great many other metal ions do, however,

form chloride complexes which are absorbedl by Dowex I resin, 40-42.
Beryllium :fiay therefore be separated from these elements by simply

passing the solution in hydrochloric acid of appropriate strength

20
through a Dowex I resin column. Unwanted ions will be adsorbed while
beryllium will pass through unadsorbed.

Even though beryllium shows negligible adsorption onto Dowex I resin
from 12 M HCI solutions, it is interesting that there is adsorption of
beryllium from 13 M LiCl -soluti'on. 43 With a distribution coefficient of
8 in this solution (Be adsorbed per Kg resin/Be remaining per liter
of solution) beryllium could be separated by anion exchange from non-
adsorbable elements such as alkali metals and magnesium by this technique.

Anion exchange separations of beryllium based on the formation of
negative complexes of beryllium do not appear to have been extensively
used. Ehmann and Koh::nzmz'8 have used the oxalate complex of
beryllium to effect radiochemical purification of beryllium. Beryllium
chloride solution, after evaporation to dryness was taken up in 0.1 M
HZ.CZ.O4 - 0.15 M HC1 (pH = 0. 9) solution and passed through a 4" x 1/2"
column of Dowex I resin at a flow rate of 1 ml/min. Elution was by
the same solution, which effected the eleution of beryllium in 5 resin
volumes.

Nelson and Kraus’® studied the peparation of the alkaline earth
elements by anion exchange using citrate solutions and Dowex I resin.
Beryllium is more sirongly absorbed than the other Imembers of the
family at low citrate concentrations, although at citrate concentrations
greater than about 0.1 M magnesium is more strongly absorbed than
beryllium. Effective separation of beryllium from Ca, Sr, Ba and Ra
may be accomplished by this technique, but the sepax.-at'ion from magnesgium
is less satisfactory. Using 1 M (NH 4) 3Cit at pH 8 beryllium comes off
first, but the last portion of beryllium will be contaminated with magnesium.
Alternatively, using 0.2 M (NH 4)3Ci‘l: at pH 4. 3 magnesium comes off
first but tdils badly and contaminates the beryllium as it is eluted from

the column.

IV. PROCEDURES FOR DISSOLVING SAMPLES CONTAINING
COMPOUNDS OF BERYLLIUM

Inasmuch as the common salts of beryllium, the chloride, fluoride,

nitrate, sulfate etc., are freely soluble in water, the problem of

21
dissolving the sample is that of rendéring soluble the matrix material
in which the beryllium is imbedded. For the gpecial case of beryllium

. metal itself the best solvents are hydrochloric or sulfuric acid. The
metal also dissolves in alkali hydroxide soluticns owing to the amphoteric
character of the element. Nitric acid, either concentrated or dilute,
is not a suitable solvent for it renders the metal passive.

The radioberyllium content of meteorites and of varicus sediments
and rocks is of considerable interest to the geochemist. F¥or iron meteorite
material aqua regia is the solvent commonly employed. For siliceous
materials HF is the appropriate solvent; the silica is volatilized,
eliminating a bulky and otherwise troublesome component from the
sample. At the same time the beryllium forms a complex with fluoride
which should ensure good carrier-tracer exchange. However, care
should be taken to decompose the fluorides, and the beryllium
complex, before proceeding with the separation. The BeF 4= complex
ion is similar in behavior to the SO, anion. The best method for
destroying the BeF 4 complex is to trgat the sample with HBO 3 after the
bulk of the fluorides have been decomposed by treatment with HZI\TO3 or
HZSO 4 . |

Because of the formation of BeF 4_ complex ion with fluorides, the
use of a NaF fusion to render soluble the beryllium in siliceous samples
has been reported by Ru.mlig.

V. COUNTING TECHNIQUES FOR USE WITH ISOTOPES OF BERYLLIUM

Counting of Be7
The only ohservable radiation from BeT is a y ray of 0. 477 Mev

energy emitted in ~ 42% of the decays (see Part II). Scintillation
counting is the obvious choice for detection of these y rays. Because
of the possibility that other y-emitting species, or |3+—emi1:ting 'species
which would give rise io 0.54 Mev annihilation quanta, might be
present in the sample the counting of Be7 can be done with assurance
only if a y ray spectrometer 1s available for exemining the y ray
spectrum from the sample.

In addition to the criterion of radiochemical purity, i.e. the
beryllium sample for counting must show only a 0. 477 Mev ¥ ray,

22
one may also require that the sample emit no particle radiations,
since Be7 emits none. In particular; this is a requirement when Be7
is produced in nuclear reactions in the laboratory. As discussed in
Part 1I, production of §~emitting Beio in significant intensities in
these instances is negligible. For the study of Be7 produced in nature
by cosmic ray action, Beio is also known to be 1:>roc1uLceciié)—fi'8 S0
that a low intensity of § emission from Bei0 is to be expected.

A third criterion of the radiochemical purity of a beryllium sample
is the half-life for decay of the sample, which should be 54 day.
Because of the long time lapse required to egtablish a half-life of
this magnitude, particularly for samples of low activity, it is generally
desirable to establish the radiochemical purity of the sample by other
means.

Where other means of establishing the identity of a radioactive
species are lacking, the constancy of the specific activity {counting
rate per mg of sample) of the sample when put through a number of
radiochemical purification steps is usually sufficient to demonsirate
that the activity is isotopic with the element of the sample.

The most difficult situation for extablishing the presence of
Be7 in a radiochemically pure condition in a counting sample arises when
the intensity is very low, of the order of 30 ¢/m or less, in which case
it may be very difficult to obtain an accurate 7 ray spectrum or to
detect low intensities or particle-emitting impurities. One must then
fall back on the constancy of the specific activity as a criterion for
establishing the identity of the activity which is being counted. One
must therefore have a very reliable and specific radiocchemical procedure
for beryllium in order to minimize the possibility of having a radioactive
contaminant in the counting sample. In this regard it is worth drawing

attention tc the nuclide "1‘12029 which decays by K and L capture to

HgZGZ with the emission of 0. 44 Mev y rays. Is y ray energy is so

close io that of Be7 that the chance of producing this species by

nuclear reactions on mercury and lead isofopes should not be ocverlooked.
. The clogeness in energy of the ¢ ray of Be7 to 0. 51 Mev annihilation

quantz makes rather easy the determination of absolute disintegration

rates of Be7 samples. Solutions of the §5+—emitting species Naz

which have been accurately standardized for their sbsolute specific

23
activities are commercially available for calibration purposes.
Provided the source is sufficiently thick to stop all positrons, the
rate of emission of 0.51 Mev annihilation quanta will be just twice the
positron emission rate of the source. The éource may then be used to
determine the detection efficiency of the scintillation detector for
0. 51 Mev quanta, which will be very close to the detection efficiency
for 0.477 Mev quanta.

N’a22 ‘has also a 1. 28 Mev y ray which complicates matters somewhat,
since this y ray will also give rise to some pulses equivalent in
energy to those arising from 0. 51 Mev quanta. In 6rder to get around
this difficulfy it is necessary to determine the detection efficiency of
the scintillator in the neighborhood of the 0. 51 Mev photo peak. This
is best done using a ecintillation spectrometer with a window which can
be opened to straddle the photopeak. Cdntributions to the observed
counting rate within this window from the 1,28 Mev y ray of a Na>?
source may be estimated in the following way. The counting rates
in the energy region a little above and a little below the 0.5%1 Mev
photopeak is first measured using a rather small window to obtain the
counting rate per unit window width in these two regions. These
counting rates will be aJinost entirely due to 1. 28 Mev quanta, and can
be used to estimate the contribution to the counting rate in the region
of the 0. 51 Mev photopeak by ihterpolation between them. In a typical
2 inch well-type scintillation detector the contribution from 1.28 Mev
quanta to the counting rate in the 0. 54 Mev photopeak amounts to about
17% of the total. '

Having established the counting rate, R, of annihilation quanta which
fall within the window of the spectrometer, the detection efficienty, E,
of the spectrometer with the window straddling the 0. 54 Mev photopeak
is given by

' R
E—fif&

D is the positron emiasion rate of the source and fa is a factor
to correct for absorption of 0. 51 Mev quanta within the source. Provided
the source is not too thick, fa is not a very significant factor, and can
be made to cancel a similar correction factor for beryllium if the

Naz'2 sample is about the same thickness as the beryllium samples.

24
Having determined the counting efficiency of the scintillator for
0.54 Mev quanta, the base line of the spectrometer is shifted downward
an appropriate amount so that the window of the spectrometer straddles
the 0.477 Mev photopeak of Be7. The same window width should be used
as for the 0.54 Mev annihilation photopeak, in which case the detection
efficiency of the spectrometer is very close to E. For a typical 2 inch
Weil—type scintillation detector E has a value of about 6 percent for
0.5 Mev quanta.

Restricting the energy interval in which pulses wili be counted o
the photopeak resulis in an appreciable loss in counting rate of the
source over that which could be obtained if a window were not used, With
strong Be? source the disintegration rate of the source could be
determined as outlined above and the sample used to determine the
counting eificiency of a scinfillation counter which counts all pulses above
a minimum threshold. This is satisfactory for sources with counting
rates in excess of a few hundred counts per minute. With very weak
sources, however, counting with a2 window is usually to be preferred
because it resulis in a more favorable sample-to~-background counting
ratio. |
Counting of Be10

Because of the long half life of Beio, and the fact that this nuclide is
likely to be of importance only in nuclear reactions produced through the
action of cosmic rays, the disintegration rate of any sample containing
Béio will be very small indeed. When the low B decay energy of
0.555 Mev is congidered also, the counting of Beio becomes a formidable
task. Evidently Geiger or proportional counting of thin samples in
some type of low level counter is called for.

Since procedures are available for isolating beryllium in carrier-
free amounts, counting samples which are very thin can be prepared.
Presumably the thickness of the final sample is limited by the
beryllium content of the starting material which is analysed. If
such a carrier-free separation were attempted, the recovery efficiency
of Beio could be obtained by measuring the recovery of a Be7 "spike"
which was added at the beginning of the analysis. Of course the amount
of B(—:f7 spike to be added should be chosen so that its counting rate does

not overwhelm that due to Beio., The much lower counting efficiency

25
of Be'? v radiation in a Geiger or proportional counter means that
roughly 100 times the disintegration rate of Be7 cofi:pared with Be10
may be present in the sample before the accuracy of counting of
Be10 is impaired.

The identity of Be10 in a sample from the carrier-free separation

of beryllium could be determined in a manner similar io that which is
10

used when carrier is present. The constancy of the ratio of the Be
counting rate to that of Be7 tracer, when repeated chemical separations
are performed on the sample, should suffice to demonstrate that any

p activity is due to Beio.

Because of the complexity of the chemical separation which may
be required in some instances for isolating beryllium in a pure
condition, or in high yield, it may be necessary to add beryllium
carrier. In this case tfie final sample for counting will have an
appreciable thickness, and the counting efficiency will be somewhat
impaired. |

Two systems for counting moderately thick Beio samples have
been described. The earlier of theseib uses a thin wall cylindrical
counter of the type described by Sugihara, Wolfgang and Libby. 46
The beryllium counting sample is mounted on the inside walls of two
hemi-cylinders by deposition from a slurry of the sample in alcohol.

The hemicylinders are then placed In close contact with the
thin wall counter. Under these conditions the geometry of the counter
is about 40%. To reduce background the coumter is surrounded by a
ring of anti-coincidence counters. Because the sample area can be
quite large under these conditions the sample can be made quite thin.
However, correction for gself-absorption of the radiations is necessary,
and may be determined by the method of Suttle and Libby. 47

Figure 7 shows an absorption curve in polyethylene of the radiations
from Be‘10 using such a counter. 16 The measurement of the absorption
curve of the radiations from a beryllium sample serves as é check
on the radioactive purity of the sample, and the data may be used'
to calculate the self absorption of the radiations by the sample,

Ehmann and Kohmanza have recenily described a counting procedure
for measuring very low levels of Beio and other naturally-occurring

' radioactive species. They use a side-window counter having a window

26
 

 

 

 

 

 

=
[ g 1.0
-_ j W a9
»
g 08
- 5 or}
{ £ o.e
o w
- dJ 0.8
o
t 2 0.4
E g 0.5 - 1 e el -l 2 1
t 0O W 20 30 40 60 60 70
-

SAMPLE THICKNESS (mg/cm*)

Fig. 8. Relative counting rate per

 

unit weight of sample for

 

 

samples of Bel0 in BeO of

|
O 10 200 30 40 5 € 70

ABSORBER THICKNESS (mg/tm’)

e ———— e L

 

fixed specific activity vs,

the sample thicknesses.

Fig. 7. Absorption curve of BelO in
Data of Ehmann and Koh-

olyethvlene in close cylin-
potyethy Y man, reference 28. The

drical geometry. Data of ' _
: extrapolation to zero

- Arnold, reference 16. .
_ thickness was made from

data of Nervik and Steven-

son, reference 47,

area sglightly over 6 cmz, with a surrounding shield of anti-coincidence
counters. The sample is placed in a dish close to the window of the _
counter in a geometry close to 40%. 'This system is inherelntly simpler
to construct and operate, although counting samples will generally not
be quite so thin as in the thin wall counter described above. However,
self scattering in moderately thin samples helps to overcome the effects

of self absorption as shown in Figure 8.

27
VI. COLLECTION OF DETAILED RADIOCHEMICAL PROCEDURES
FOR BERYLLIUM '

PROCEDURE 1

Separation of beryllium from stone meteorite material

Source - _W.

'D. Ehmann and T. P. Kohman, Geochim. et Cosmochim.

Acta 14, 340 (1958).

Procedure:

Step 1,

.Step 2,

Step 3.

Step 4.

' Rinse the specimen with acetone to remove any laquer which

may have beén used to preserve it.

Grind a 50-150 g sample of the Speci.’men to a find powder
using an électrolytic iron sheet and iron roller. Transfer
this fine powder to a 1 liter polyethylene beaker which is
placed in a waterbath at room temperature.

Dissolve the sé.mple in a hood by the cautious addition of

48% hydrdfluoric acid. (Note 1) ‘About 5 ml of hydrofluoric
acid per gram of sample is used. Allow the mixture to |
gtand at room temperature for 3-4 hours with occasional
stirring. . _ :

Heat the mixture on a water bath at 100° C, with occasional
stirri.ng,-until the mixture goes just to dryness. Add 50 ml
of HF to the residue and aé‘ain evaporate to dryness.' Add -'

50 ml conc. HN03 to oxidize iron and again reduce to dryness.
Dissolve the residue in 100 ml of conc. HC1 and again
evaporate to dryness tb femove.excess HF and HN_O3'. Repeat
the evaporation with 100 ml of conc. HCI.

Dissolve the residue from the evaporation in 1 1. of 9-10 M
HCl. Filter through a funnel with fritted glass disk to remove

‘insoluble residfie which is usually found in trace amount.

Add an accurately known amount of Be carrier to the solution

and transfer the solution to a 2 1. separatory funnel.

28
SteE 8. .

Step 9. .

Step 10,

Step 11.

Step 12.

SteE 13,

SteB 14,

PROCEDURE 1 (CONTINUED)

Extract iron with consecutive 306 - 400 ml portions of isopropyl
ether which has been saturated with 9 M HC1. Three of four
extractions are usually sufficient. Wash the combined ether
extracts three times with 50 ml portions of 9 M HCl, combining
the washings with the extracted-aqueous phase.

Reduce the volume of the solution to about 250 ml on a hot plate.
To this solution add 500 ml of 12 N HC1, making the solution
approiimately 10.M In HC1. Pass the solution through an

ion exchange column approximately 2.5 cm in diameter containing
200 - 250 ml of Dowé_x 1, X-10, 100 - 200 mesh ion exchange
resin. Adjust the flow rate 1o approiimately'i ml/min, (Note 2)
Wash the column with 500 ml of 40 M HC1 and commbine the eluates.
Reduce the volume of the solution to 300 ml on a hot plate.

Add NH ,OH to pH 7 to precipitate Al and Be hydroxides.

Filter through a Millipore HA filter in a 6.5 em Buchner funnel
and wash with 25 m] of 5% NH ,C1 adjusted to pH 7.

Dissolve the precipitate in dilute HC1 and reprecipitate and
filter as in Step 9. Repeat the precipitation fithir_d time.
Transfer the precipitated Al and Be hydroxides on the filter
paper to a 250 ml beaker. Add 25 ml of 8 M NaOH and 10-20
mg of Fe (IM) carrier. Macerate the filj:er paper and heat

the mixture to boiling. Filter the warm slurry through a

funnel having a 6.5 cm fritted glass disk. |

Wash the solids in the funnel with a small amount of hot water,
combining the washings with the filtrate, Dilute the solution

to 250 ml with distilled water and treat the solution with 6 M HC1
io precipitate Al(OH)3 and Bca-,(OH)z at the methyl red end poini;.
Filter off the precipitated hydroxides and redissolve them in
dilute HC1. Reprecipitate the hydroxides with NH ,OH at the

4
methyl red end point. Filter the precipitate and again repeat

- the precipitation at the methyl red end point.

Dissolve the precipitated Al and Be Bydroxides in the minimum -
amount of 6 N HC] necessary to yielldh- complete solution. Dilute

- the solution.to approximately 50 ml with distilled water and

29
Step 15.

Step 16,

Step 17.

Step 18.

- PROCEDURE 1 (CONTINUED)

adjust the acidity to 1.4 M HC1 by dropwise addition of 6 M HCI,
using a pH meter and standard 4.1 M HCI solution for comparison.
Pass the solution through a 25 ml resin volume of Dowex 50,
X-8, 50-100 mesh ion exchange column about 41/2 inch in
diameter and 10 in. lo-ng.' Adjust the flow rate to 1 ml/min.
After the solution has passed through the column elution is
continued with 1.1 M HC1 until Be is completely eluted,

usually in about 6 or 7 resin volumes. (Note 3)

Evaporfite the effluent containing Be to dryness on a steam
bath. Dissolve the residue in 25 ml of 2 M HCl, Pass the
solution through a 5 ml Dowex 1 ion exchange column 2 in.

long and 1/2 in. in diameter. After passage of the sample
solution the column is washed with 10 ml of 2 M HC1 and the
washing is added to the first eluate. Pb+2 is adsorbed in

the column.

Evaporate the eluate containing the beryllium to dryness.

~ Dissolve the residue in 25 ml of 0.4 M H,C,O, - 1.5 M HC1

S22 4
(pH = 0.9). Pass the resulting solution through a Dowex 1

column 4 in. in length and 1/2 in.- in diameter at a flow
rate of 4 ml/min. Continue elution with 0.4 M H,CO, -
0.45 M HCI until 5 resin volumes (about 50 ml) of the eluting
solution has passed through the column. Residual Al is

"adsorbed on the column while beryllium passes through.

Treat the eluate from the column with NH 4OH to pH~ 7 to

precipitate Be(OH),. Filter the precipitate on Millipore HA

filter paper in a 6.5 cm Buchner funnel. Ignite the
precipitate at 1000°C, weigh the BeO to determine a chemical
yield, and mount the sample for counting. (Note 4)

Recycle Procedure:

Step 1.

Transfer the BeO from the counting tray to a beaker and
treat it with a mixture of 15 ml conc. HNO, and 15-ml
9M HZSO 4+ Boil the mixture on a hot plate for 4 hour, or

30
Step 2.

Step 3.

Step 4.

Step 5.

Step 6.

Step 7.

PROCEDURE 1 (CONTINUED)

until the solution is complete. Dilute the solution to 400

ml with distilled water. |

Add about 10 mg Fe (III) carrier to the soluticn and precipi-
tate Fe(OI—I}3 and Be(()H)2 with NH4OH at pH ~ 7. Filier the
precipitate on Whatman No. 31 fiiter paper ina 6.5 cm
Buchner funnel. _ .

Transfer the filter paper and hydroxides to a 250 ml beaker
and treat with 15 ml of § M NaOH solution. Heat the solution
1o boiling and filter the warm slurry through a funnel having
a 6.5 cm fritted glass disk. Wash the residue with 40 ml

of & M NaOH adding the washings to the filtrate. '
Dilute the combined solutions to 100 ml and add 6 M HC1

to precipitate Be(OH)2 at pH ~ 7. Filter this precipitate

on Millipore HA filter paper in a 6.5 cm Buchner funnel.
Dissolve the precipitate and r’ei)recipitate twice with NH 4OH
at pH ~ 7 to assure removal of the Na+ present,

Dissolve the final Be(()H)‘2 precipitate in 25 mi of conc,

HC1 and pass the solution through a 410 ml Dowex 4 anion
exchange column 4 in, long and 4/2 in. in diameter. Rinse
the column with 20 ml of conc. HCI after introduction of

the sample. _

Reduce the combined effluents from the column to 40 ml by
evaporation on a hot plate. Add 20 mi of distilled water

to make the resulting soiution about 2 M in HC1l. Pass

this solution through a 10 ml Dowex 1 column and rinse

the column with 20 ml of 2 M HCl,V

Combine the effluents frém the column and evapcrate them

to dryness, Disgolve the residue in 25 mlof 0.1 M H_ C_O

27274
0.45 M HCI and proceed as from Step 17 in the Procedure.

(Note 5). _

NOTES

1. Violent effervescence is prevented by the use of the water bath for

cooling and the slow addition of the hydrofluoric acid.

31
PROCEDURE 1 (CONTINUED)

. . +6 44 4 _.+ :
. Residual Fe+3, Co+2, Cr+ y U Pa.+5, Po+ , Bi 3 and about thirty

: . +2 +3
other elements are held in the column (log D> 1); while Ni -, Al -,

'_Ca+2, Th+‘.4, , Pb+2,' Ra+2, and Ac? of the elements of interest pass
freel;)lr through- (no adsorption). The alkali elements and the other '
alkaline earth elements are also not absorbed.

Al-l-3 is held on the column, but would start to elute at about 12 to

15 resin volumes of 1.1 M HC1. _

It is recommended that a dust mask be worn to prevent the inhalation
~ of very toxic BeO dust. ' |

The chemical procedure as given is not completely satisfactory inas-
much as the initia.l.radioacti'vity usually decreases on recyéling. _
The initial chemical yield someflmes exceeds 100 percent, indicating
_incoi:nplete separat'ion from bulk consfituents, although a given -
specimen of stoney meteorite might contain appreciable amounts of
beryllium, It éppeara that at least three recyéles may be necessary -
to get rid of all contaminating activities and inert impurifies. The
introduction of an extractiofi step using acetylacetone, following thé

. directions given in Section IIIJ:', would probably brove of value in
eliminating these difficulties. Such an extraction step could be
introduced after step 13, using an excess of EDTA to hold back Al,
or the extraction could be carfied out following Step 17 after
precipitating Be with NH 4OH.

PROCEDURE 2

Separation of beryllium from iron meteorite material

Source - W. D. Ehmann and T. P. Kohman,l Geochim et Cosmochim.

Acta 14, 340 (1958).

Procedure

‘Step 1. Wash the sample, which may weigh from 100 to 150 g, with

distilled water and acetone to remove terrestrial dirt
a.nd any lacquer which may have been used to preserve the

gpecimen.

3z
Step 2.

Step 3.

SteB 4,

Step 5.

Step 6,

PROCEDURE 2 (CONTINUED) .

Place the sample in a 2 1, beaker and treat with consecutive.
200 ml portions of aqua regia. Afier reaction has ceased

pour off each portion into a separate beaker. Continue thig.

- ifreatment until the specimen is completely dissolved.

To the combined solutions add 25 ml of conc. HNO3 to ensure

oxidation of iron (II). Evaporate the solution to near d‘ry'nes_s

with several 500 ml portions of conc. HC1 to remove excess

H_NO3. | o
To the small volume from the last eVa_poration add sufficient

9 M HCI1 to brifig the volume up to 1 1. Filter the solution
through a Whatman No. 50 filter paper in a Buchner funnei.

A small residue, possibly graphite, may be discarded.

Add beryllium carrier and carriers for other radioelements
which it may be deeired to sepa.raté. Transfer the solution
toadl. _s-ep'aratory funnel a.nd_exu'aét iron with consecutive
300-400 ml portiona of isopropyl ethelr s#turated with 9 M HCI.
Three or four extractions are usually sufficient.

Combine the ether layers and wash them three times with

50 ml portions of 9 M HCl. Add these washings to the aqueous
phase. Proceed as from Step 8 of Procedure 1 for separating

beryllium from stqfie meteorite material. (Notes 1, 2). _

- NOTES

1. The chemical yvield of heryllium sometimes appears to exceed 100 per -

cent. However, the weight of BeO often decreases apbreciably on

recycling, i.mplying that the appa.rént extra yield comes from

'J'.ncomplete separation from bulk constituents rather than from

béryl]_ium present in the meteorite, -

2. See Note 5 of Procedure 1.

33
PROCEDURE 3

Separation of beryllium from deep-~sea sediments (I).
Source - P. S. Goel, D. P. Kharkar, D. Lal, N. Narsappaya, B.
Peters, and V. Yatirajam, Deep-sea Research 4, 202 (1957).

Core samples of ocean-bottom sediments weighed between 66 and
139 grams when rdry. Beryllium was recovered from them without
addition of beryllium carrier by the following procedure. The recovery
efficienty was determined to be 80 & 10% by spiking some sample

7
sediments with Be {racer before the analysis.
Procedure:

Step 1. To the dry sample add 500 m] conc. HC1 and 250 ml conc.
. HNO 3.‘ Heat to destroy organic matter and to drive off

the acid. Destroy nitrates by repeated evaporation with
conc. HCIL. -

Step 2. Boil the semi-dry residue for 45-20 min. with conc. HCI,
dilute with 300 ml water and heat the mixture to boiling.
Allow the solids to settle and decant the solution. Wash
the solid residue with 100 ml portions of 6 N HC1I until
free of iron. Combine the solutions (Solution Li). ‘

Step 3. Boil the solid residue with 120 g NaOH in a glazed silica
dish for 15 min and filter off any undissolved solid
(Solution M). Fuse the solid residue with five times its
weight of Na,CO, and dissolve the melt in 100-150 ml
of water. Filter off and discard any insoluble residue
(Solution N).

Step 4. Combine solutions L; M and N and heat to drive off COZ'
Add ammonia to pH 8 to precipitate insoluble hydroxides.
Filter the mixture, discarding the filtrate. Dissolve the
precipitate in 200 ml conc. HCI.

Step 5. Evaporate the solution to dryness twice with additions of
HCI1 to precipitate silica. Boil the precipitate with
400 m] of 6 N HC1 and filter (Solution O).

Step 6. Moisten the silica residue with H,SO, and heat with 48%
HF to remove SiOz. Fume any remaining residue with HZSO4,

ignite it and then fuse it with NaZCOB' Dissolve the melt

34
Step 7 .

Step 8.

Step 9.

Step 10.

Step 14,

Step 12.

Step 13.

PROCEDURE 3 (CONTINUED)

in HCI1 and filter. Combme the filtrate wrr.h Solutlon O _ _
Add ammonia to Solution O to bring the pH to 8. Filter the
precipitated hydroxides and discard the filtrate. Dissolve .

' the precipltate in 500 ml 6 N HCI.

Extract Fe(IIl) from the solution by shakmg with 1 liter |
of ether. Concentrate the aqueous phase to 150 ml, add
15 g NH,C1 and cool in an ice bath. Add 300 ml of ether
and pass in HC1 gas. Filter off the precipitate of Al and
Ti chlorides. Evaporate the filirate to 50 1l volume.
Adci 8 g disodium EDTA to tfie solution é.nd adjust the pH

to 4.5-5.0 by the addition of dilute NH OH. Add 2.5 ml

_acetylacetone a.nd shake for 5 minutes.

Extract beryllmm from solutlon with four 100 ml pOI“thIlS

of benzene, shaking the 1_'_nn_rture for 10 minutes each time. :

_ C._ombine the benzene layers and back-extract beryllium
by shaking with four 175 ml portions of 6 N HCI.

Combine the HCI extracts and evaporate the solution to

dryness. Destroy any organic matter by evaporation with

_afiua regia. Take up the residue from the evaporation in

about 40 mlof 1 N HCl _

Cool the solutlon in an ice bath and add 10 ml of 6% cupferron
solution. Extract the mixture with three 40-ml portions of
CHCls; and discafd the Qrga.n_jlc:phase_. Evapo_rate the

-agueous phase to dryness and decompose organic matter

by evaporation wrth HNO _ .

Decompose residual nitrates by bo:ling the residue with
HC1l. Evaporate ’ghe golution to dryness and take up the
residue in 5 ml of dilute HCl. Transfer the solution a little
at a time to a plastic counting dish and evaporate to dryness

under & heat-lamp.
. PROCEDURE 4

Separation of beryllium from deep-sea sediments (II),
Source. - P. S. Goel, D. P. Kharkar, D. Lal, N. Narsappaya; B.
Peters, and V. Yatirajam, Deep-gea Research 4, 202 (1957).

A simplified procedure for recovering Béio from samples of ocean- '

bottom sediments, assuming that the beryllium is adsdrbed on the

surface of the clay particles.

Procedure:

- Step 1.
~Step 2.

Step 3..

SteE 4
Step 5.

Step 6.

Add 5 mg of BeO to the dried sample and heat the sample to

500°C in a muffle furnace for 2 hours to destroy orga:uc

matter

Leach the_a igfii‘ted material 4 times with 190 mi of conc. HC1
and then wa.sh'the ins.oluble residue with 1:1 HC1 solution
until the washirigsi are colorless.

Combine the acid leach and washings and evaporate the
solution to small volume. (N ote 1) Take up the residue

in water and add 400 g of disodium EDTA. AdJust the

pH of the solution to 4.5 - 5. '

_ Add 5 ml acetylacetone and shake for 5 minutes. Then

extract the solution with four portions of benzene, shaking

the mixture for 10 minutes each time.

‘Wash the combined benzene éxtracts with water at pH 5.

Discard the washings and back extract beryllium with
four portions of 6 N HCI. | ' |
Transfer the solutlon a little at a time to a plastlc counting

dish and evaporate to dryness u:;der a heat lamp. (Note 2)

NOTES

1. The procedure as quoted in the original article states that an

acetylacetone-benzene extraction is carried out directly on the

HC1 solution after the .disodil.i_m EDTA has been added. Since the

extraction with acetylacetone must be carried out from solutions

of pH greater than 4,5, the éonsiderahie quantity of base which

would be needed to bring the strongly acid solution to the proper

36
- PROCEDURE 4 (CONTINUED)

pH would result in a very large volume of solution to be extracted.

The details of the procedure from this point onward are not given

in the original article. . Steps 3, 4 and 5 represent an attempt

at giving epecific details of the procedure based upon information .

given in the original article.

2.. It remains to be demonstrated to what extent this simplified

procedure is capable of recovering Bd-:-10 from samples of

sedimentary material.

PROCEDURE 5

- Separation of beryllium from Clay by a solvent extraction procedure.

Source - J.

R. Merrill, M. Honda, and J. R. Arnold,

(1o be published). .

Procedure:

Step 1.

SteE 2.

‘Divide the clay sample into ca. 100 g units. Disperse each

of them in a small amount of water in a 1 liter, heat-
resistant polyethylene beaker. To the mixture slowly add
250 g of 48% HF followed by 80 ml of concentrated H,SO
Add about 10 mg of beryllium carrier to the mixture.
Tranefer the mixture to a 300 ml platinum dish and heat very

4

' plowly over a small gas flame. Continue heating until the

Step 3.

Step 4.

viscous solution which remains begins to solidify. Cool
the mixture. |
Heat the residue with 300 ml of water. Centrifuge any

‘undiesolved material, which should consist mainly of black

organic matter and aluminum and calcium sulfates (Note 1).
i much ma&acked _oi-iginal sample is present further
bisulfate treatment is necessary. Combine the superpatant
solutions from the several clay fi.n.it& {Note 2).

To the combined solutions add EDTA in about 20% excess
over the amount estimated for complexing the Fe and Al
present. Add sufficient-water to bring the volume of the

solution to about 3 liters.

a7
Step 5.

~ Step 6.

Step 7.

SteE 8.

Step 9.

Step 10.

PROCEDURE 5 (CONTINUED)

Adjust the pH with ammonia to about 6,4 (Note 3).- When
the solution becomes cool again add 25 ml of acetylacetone

‘and stir until it is dissolved. Transfer the solution to

a large separatory funnel and extract the beryllium complex

. with three 250 ml portions of benzene (Note 4).

Combine the benzene sxtracts and wash them with 500 ml of
water bufféered to pH 5-6 with dilute acetate. Discard the
aqueous layer Back-extract bery]lium'from the benzene
golution with two 4150 ml portlons of 6 M HCL.

Combine the HC1 extiracts a.nd add 45 g of dlsodlum EDTA and
enough ammonia to brmg the pH to 6 4. Allow the solution
to cool, then add 40 mil of a.cetylacetone and stu‘ until it 13

dissolved Transfer the solution to a sepa.ratory fu.nnel a.nd

extract with three 100 ml portions of benzene.

Combine the benzene extracts, and after washing with 200 ml-
of buffered water, back-extract beryllium with two 50 ml

‘portions of 6 N HCl. Combine the HCI1 extracts in a large

beaker, add 10 ml of conc. Pm03_and heat the solution
(caution!). Boil the solution nearly to dryness with

- repeated additions of HNO 3

‘Take up the residue from the evaporation in water and add

ammonia to bring the pH to 8. Filter the precipitated Be(OH)Z-
and ignite to BeO.

. Weigh the BeO to determine chemical yleld and mount for
counting (Note 5). |

NOTES

1. Ina prel:.mmary experunent a Stockton shale sample was used as

a:model and Be tracer was used to measure the recovery of bery]_lium.

With about 10 mg of beryllium carrier it was found that the hot water
.extracts of the sulfate cake contain almost all of the beryllium

whereas 70-80% of total aluminum was left in solid form.

2. Sometimes the brown supernatant solution cbnta.ins some suspension

(aluminum compound)

<38
PROCEDURE 5 (CONTINUED)

3. The color of the iron - EDTA complex is useful as an indicator.

4. Occasional difficulties of separation -re'quire- centrifuging the organic

layer at thie step.

5. The over-all yield of beryllium is about 60-70%. The procedure has

been sufficient to remove all :adioiactive impurities from the clay

samples which were analysed, but beryllium carrier is fiecessd’ry

for good results.

PROCEDURE 6

Separation of beryllium from clay by an ion exchange procedure,

Source - J. R.. Merrill, M. Honda, and J. R, Arnold, (to be published).

Procedure:

Steps 1-3

 Step 4.

Sj:e.g 5.

Step 8. -

As in Procedure 5, using 20 mg of BeO carrier for a

' 200-300 g clay sample.

Take 0.5 ml of the combined aqueous extracts of the sulf_fite
cake and ana.‘l,ysé by EDTA complexiometric titration for
Fe and Al (Note 1). | " |
Addgraduallyamlxture of 2H 4 t 1Na »H Y-Z H O'+

5 CaCO to the solution untfl about 0.1 mole of excess EDTA

over that needed to complex Fe and Al, has been added.
Adjust the pH to 3.5-4 with more CaCOB (usually about 100 g).
(Note 2).

Add 60 ml of glacial acetic acid as a bui'fer_(Note 3).

Filter off the insoluble .CaSO 4" f.;'aCO3 and dilute the

filtrate and washings to 10 liters.

Pass the solution through ai li,ter" _D'owe:x 50 x 8 ion

excha.ngé column in the sodifi:fi form. After this solution
hae passed through, pass through 1 liter of 0.01 M EDTA +
0.1 M NaAc + 0.5 M HAc to remove any traces of Al and Mn

‘adsorbed on the column. {Note 4).

Elute beryllium from the column with a solution of 0.5 M
NaAc and 1 M HAc. About 0.5-1.5 column volumes of
effluent contain all the berylllum.
PROCEDURE 6 (CONTINUED) -

Step 9.  Precipitate Be(OH), from the effluent by the addition of

ammonia. Filter the precipitate and ignite to BeO. Weigh

to determine che_m.ical yield and mount for counting.

' NOTES

For discussions of complexometric titration see G. Schwarzenbach,
Analyst 80, 713 (1955); ''die Komplexometrische Titration", G.
Schwarzenbach, F Enke, Stuttgart (1955); "Complexometric
Titrations', G. Schwarz.enbach and H. Irvmg, Methuen and Co. Lid.,
London, Interscience Publishers, Inc., New York. (1957).

Calcium carbonate is used to raise the pH 80 that the electiro-

lyte concefitration will not be increased. Béry].liufn is not
copercipitated with CaSO 4 | .

If appreciable amounts of Mg or Ca are in solution they will

replace Na+ from the ion exchange resin used in the succeeding

step. In the presence of excess EDTA this increases the pH of
~ the solution, the most important variable in the process. To prevent

. this enocugh HAc is added to the mixture to make the fina.l solution

0.1 M. .
The completeness of removal can be checked by complexometric
titration of the effluent.

| PROCEDURE 7

Separation of berylllum from clay
. Source - J. R. Arnold, Sc1ence 124 584 (1956).

| Procedure:

Step 1. . The sampl.e , consgisting of several hundred grams of wet

clay, is treated with a mixture of 500 g of 48% HF and
500 g of 12 N HC1 in two 1 liter HH polythene beakers, after
10 ml of Be carrier (approximately 60 mg BeO equivalent) .-
has been added. Evaporate to dryness in a hot-air jet.

40
Step 2.

Step 3.

Step 5.

Step 6.

'SteB T.

Step 8.

Step 9.

PROCEDURE 7 (CONTINUED)

Add 150 g of each acld and again évaporate to dryness
Evaporate to dry'ness twice more with a total of 500 g

of HCI1 to remove most of the fluoride.

Take up the sample in 1500 ml of 41 N HCI, boil, decant, and
cent_rlfuge Heat the remaming golid with H SO until

HF bubbles cease,

Take up the cake with water and fuse any remaining solid

with KHSO,. After dissolving the melt in water, discard

any solid which remains and combine all solutions.

- Add 650 g of tétrasodium EDTA and bring the solution to

pH 6 to 6.5. Add 25 ml of acetylacetone, and after the

solution has stood for 5 minutes_.exfract with three 250-ml

- portions of reagent-grade benzene. Combine the benzene

extracts and backwash them with acetate -buffered water at
pH 5.5 to 6. ‘

Extract the benzene layer with two 150 ml portions of 6 N
HCl-a.nd discard the orgehic phage. Add 45 g of disodium
EDTA to the aqueous extracts and adjust the pH to 6 to 6.5.
Add 10 ml of acetylacetone, and after the solution has

stood extract it with three 75 ml portiens of benzene.
Combine the benzene extracts, backwash them with acetate- |
buffered water at pH 5.5 te 6, and then back-extract with

two 50-ml porl:ion.e of 6 N HCi. Discard the or'ganic phase.
Boil down the aqueous phase nearly to dryness with the addition
of HNO to destroy organic matter, Take up in 50 ml of

water a.nd preciplta.te Be(OH)Z with ammonia. Fflter the

precipitate and ignite to BeO.
Weigh the BeO to determine chemical recovery e.nd mount

for counting.

41
PROCEDURE 8

 Separation of beryllium from aluminum target material.
Source - E. .Baker, G. Friedla.nder and J. Hudis, Phye Rev. 112,
1319 (1958). '

Bombarded aluminum targets contain Na.zz, which gives 0.51 Mev

quanta that J'nterfere with the counting of the 0,48 Mev ¥ ray of Be.

. Procedure:

SteE 1.
Step 2,

SteE 3.

‘Dis_solve_ the aluminum in acid and add beryllium carrier.

Prec'J'_.pitate beryllium and aluminum hydroxides with ammonia.
Centrifuge and discard the aqueous phase. |
Dissolve tlie mixed hydroxides in concentrated hydrochloric

acid, add an equal volume of ether to the solution, cool in

.. an ice bath, and saturate the solution with HCI gas.

Step 4..

Step 5. .

Step 6.

SteE 8.

Centrifuge and discard the precipitate of A_.Cl -6 H 50.

Evaporate the 11quid phaee to small volume on a etea_m bath.

Add dlstilled water and prec1p1tate Be(OH) w1th ammonia.

C_ent_rlfuge and dl_s_card the aqueous phase.
Dissolve the precipitate of Be(OH), in glacial acetic acid
a_fid transfer the solution to a casserole. Evaporate to dryness

on a steam bath. Repeet the evaporation to dryness with

glac1a1 acetlc acid three more times.

Take up the solld consisting of cryetals of baslc bery]lium -

acetate, in (..'JHCI3 and transfer. the _CH_C13 sqlution to a

separatory funnel. Wash the C_HC13 layer three times with

~an _equa.l volume of water. Discard the aqueous layer,
Evaporate the CHCl layer to near d.ryneee Ta.ke up the

resudue m a ema.ll amount of HINO Agam take the solution
to drynese and them d:.lute with- water. Precipltate ZE’.e(OH)z
4OH

Filter the Be(OH) prec1p1tate through a Whatman No. 42
filter paper. Transfer to a platinum crucible, char the

paper, and ignite at 1000° for 4 hour. Grind the BeO to

by addmg a slight exceas of I-]N

'a powder, glurry with 5 ml of ethanol and filter onto a-

weighed filter paper disc. Dry in an oven and weigh to
determine chemical yleld. Mount for counting.

‘42
PROCEDURE 9

Separation of beryllium from mixed figsion products and uranium,

Source - J. D. Buchanan, J. Inorg. Nuc. Chem. 7, 140 (1958),

Essentially the same procedure has been described by Baker,
Friedlander, and Hudis, Phys. Rev. 112, 1349 (1958) for the
separation of beryllium from cyclotron targets of copper, silver and gold.
Two cycles of the procedure have resulted in a decontamination factor
of 3 x 10° and a chemical yleld of 90%.

Procedure;

Step 1. Dissolve the sample in an appropriate acid and add
beryllium (about 15 mg) to the sample contained in a
centrifuge tube (50 ml). Stir well, then precipitate Be(OH)2

with a slight excess of NH 4OH. Centrifuge and discard the
supernatant solution.

Step 2. Dissolve the Be(OH)Z precipitate in 10 ml conc. HCl. Pass
through a short column of Dowex 1X-10 resin which has been
washed with conc. HC1 (Note 1). Wash the resin with 5 ml
conc. HC1l. Collect the effluent in a centrifuge tube.

Step 3. Reprecipitate Be(OH)Z with a slight excess of NH 4OH. Cen-
trifuge and discard the supernatant solution. Wash the
precipitate with 15 ml of water and discard the wash.

Step 4. Dissolve the Be(OI-I)Z precipitate in min. of conc. HC1l. Add
3 mg Fe III carrier, dilute to 15 ml and heat on a water
bath. Add 40 ml 8 N NaOH with stirring, and heat until
Il?‘e(O]EI)3 coagulates. Centrifuge and decant the supernatant
solution to a clean centrifuge tube,

Step 5. Acidify the solution with HC1 and then precipitate Be(OH)Z
with a slight excess of NH 4OH. Centrifuge and discard the
supernatant solution,

Step 6. Dissolve the precipitate in 3 ml glacial acetic acid and
dilute the solution to 15 ml with water. Add 2 ml of 10%
EDTA solution and then adjust the pH to 5 with NH 4C)H
using indicator paper.

Step 7. Add 2 ml of acetylacetone and stir the solution vigorously

for a minute with a mechanical stirrer. Add 7 ml of benzene

43
Step 8.

Step 9.

. Step 10.

Step 11.

Step 12.

Step 43.

PROCEDURE 9 (CONTINUED)

and extract berylliumm by stirring vigorously for a minute
with the mechanical stirrer. Allow the two phases to sep-
arate and transfer the benzene phase to a clean centrifuge
tube by means of a transfer pipette. Check the pH

of the aqueous phase and readjust to pH 5 if necessary.
Repeat step 7 twice more, combining the benzene éxtracts
with that from step 7. '

Back extract beryllium by adding 10 ml of 6 N HCI1 to the
benzene solution and stirring vigorously for 4 min.

Allow the phases to separate and transfer the HCl solutidn
to a 150 ml beaker using a transfer pipette.

Repeat step 9 once, combining the HCI extract with the first
in the 150 ml beaker. Discard the benzene layer, |
Evaporate the HCI solution just to drynese (do not bake).
Add 5 ml of conc. H1§03 and evaporate just to dryness.

(Note 2). '
Dissolve the residue from step 14 in 2 mi of conc. I-I.N'O3 and
10 ml of water. Add a slight excess of NH 4OH to precipitate
Be(OH)Z. . Filter with suction on Whatman No. 42 paper.
Transfer the paper and precipitate to a crucible and dry under

' a heat lamp or in a 100° oven. Ignite the precipitate to BeO

at 1000°C for 1 hr or until precipitate is snow white.

With the crucible inside a hood to avoid inhaling BeO dusit,
grind the BeO to a powder with a stirring rod. Transfer

the BeO to a tared filter paper by slurrying with alcohol.
Wash with ethanol and dry at 90-400° for 10 min. Weigh

the sample as quickly as possible as BeO 18 somewhat hj'gro-
scopic. Mount BeO for counting. '

NOTES

1. The ion exchange column is made by sealing a tip 5 mm long by 2 mm

diameter to the bottom of a 15 x 85 mm pyrex test tube, plugging the

tip with glass wool, and filling the tube with resin to a height
of about i inch.
PROCEDURE 9 (CONTINUED)

2, If a higher degree of decontamination is needed, dissolve the

residue in 10 ml conc. HCI1 and repeat the procedure from step 2.

PROCEDURE 10

Separation of berylllum from cyclotron targets
Source - J. B. Ball, G. H. Bouchard, Jr., A. W. Fairhall, and
G. Mitra (unpublished).

The following procedure is used where the target meterial is
sandwiched between silver foils and bombarded with up to 44 Mev helium
ions. Be7-which escapes from the target is caught in the silver foil.

No Be7 is produced under these conditions in the silver foil iteelf. Because
of activation of impurities in the silver foil several hold-back carriers

are usgsed to improve the decontamination of the beryllium. The procedure
is sufficiently general that a large number of target elements could be
handled without much modification. The over-all chemical yield is

in excess of 80%. |

Procedure:

Step 1. Diagolve the target and silver catcher foils in conc. HNO3.
Evaporate most of the excess acid end add Be carrier
(10 mg). Add hold-back carriers of Cu, Zn, Cd, In, Au,
Hg and T1, where poseible as nitrates (Note 1).

Step 2. Dflute the mixture to about 20 rfil with water and pass in

' HZS until the precipitated sulfides are well coagulated.
Centrifuge the mixture and decant the supernatant solution
1o a clean centrifuge tube. Discard the precipitate.

Step 3. Add conc. NH OH to the solution until the solution is
faintly ammoniacal. Centrifuge the mixed precipitate of
Be(O]E[)a and sulfides and discard the aqueous phase.

Step 4. Add 6 N NaOH in sufficlent amount (about 1 ml) to dissolve
the Be(OH) 2 from the precipitate. Dilute the mixture to
about 20 ml with water. Centrifuge and discard any
precipitate which may be present.

45
Step 5.

Step 6.

Step 7.

Step 8.

Step 9.

PROCEDURE 10 (CONTINUED)

To the supernatant solution add 3 to 4 drops of 10 mg/ml

Fe III carrier, with swirling. Centrifuge and discard the
precipitated Fe(OH)3.

Add a drop or two of methyl red indicator and barely acidify
the solution. Then add sufficient NH 4OH to turn the indicator
yellow. Centrifuge the precipitate of Be(OH)Z.

Dissolve the Be(OH)2 precipitate in a small amount of

conc. HCl. Dilute the solution to 20 ml with water and

add 2 ml of a saturated solution of the disodium salt of
EDTA. Precipitate beryllium with NH 4OH. Centrifuge and
discard the supernatant solution. Repeat the precipitation
of Be(OH)z in the presence of EDTA twice more.

Dissolve the Be{OH) 2 precipitate in a minimum of conec.
HCl. Dilute to 20 ml with water, transfer the solution

to a 50 ml plastic centrifuge tube and add 30 drops conc.
HF. Heat the solution in a boiling water bath and

slowly precipitate BaBeF, by dropwise addition of 5 ml

of a saturated solution of Ba(NO Continue heating

),
for 10 minutes and then centrifu;ezthe precipitate,
Before discarding the supernatant solution check for
completeness of precipitation by adding 1 drop more each
of Ba solution and conc. HF.
Take the precipitate up in a small amount of digtilled
water and filter the suspension through a weighed RA -type
millipore filter (Note 2). Wash with distilled water

and dry in an oven. Weigh as BaBeF4. Mount for counting.

NOTES

1. Gold carrier necessarily contains chloride ion which precipitates

AgCl.

A small amount of AgCl precipitate in the mixture makes

no difference to the recovery of beryllium.

2. The precipitate is very fine-grained and next to imposasible to

filter through ordinary filter paper.
PROCEDURE 414

Radiochemical gseparation of beryllium
Source - T. T. Shull, in "Cocllected Radiochemical Procedures',

Los Alamos Scientific Laboratory Report Lia-41724, 2nd ed. {1958)

4. Imtroduction

The determination of radicberyllium (BeT) is based upon the formation,
after the appropriate decontamination steps, of basic beryllium scetate,
Be 40 {OCOCH 3} 63 which is extractable by chloroform. The first
decontamination step carried out on a solution of the sample is a ferric
hydroxide precipitation by meang of an excess of sodium hydroxide
solution. Beryllium, as a result of its amphoteric nature, remains in
golution ag a beryllate, NaHBeOZ or NaZBeOZ‘ The beryllate is then
converted fo beryllium ion and beryllium hydroxide precipitated with
ammonia water. The hydroxide is purified by a series of acid gulfide
precipitations in the presence of molybdenum, antimony, and tellurium
carriers, respectively. Beryliium hydroxide is then changed to the
basic acetate by acetic acid treatment. The basic acetate is extracied
into chlorcoform, the chloroform is evaporated, and the basic acetate is
dissolved in nitric acid solution. BRBeryllium is finally converted to the
oxide, Be(Q, in which form it is weighed and counted. The procedure as
outlined below requires approximately 18 hours and gives chemical
yvields in the neighborhood of 35%. Although decontamination factors
have not been determined, it appears that decontamination from gamms-

emitting impurities is of a very high order.

Z. Reagents

Be carrier: 1.082 mg Be/mil {3.00 mg BeQ/ml)--(added as c.p.

| BeSO, - 4H,0 in H,0)

Fe carrier: 410 mg Fe/ml (added as FeCl3 s 6H20 in dilute HC1)
Mo carrier: 40 mg Mo/ml {added as 1'\TI-I4)61\/&)7024 o 4:H20 in HZO}
Sb carrier: .40 mg Sb/ml {added as SbC15 in 2M HCIL)

Te carrier: 410 mg Te/ml (added as TeClAL in dilute HCI1)

HCl: 6M

HC1l: conc.

HNOS: conc.

47
PROCEDURE 11 (CONTINUED)
HC2H302: glacial
NH 4OI-I: conc.
NaOH: 20% by weight aqueous solution
HZS: gas
. Chloroform:  anhydrous
Ethanol: absolute.

3. Equipment
Fisher burner

Drying oven -

Muffle furnace

Centrifuge

Block for holding centrifuge tubes

Mounting plates

Forceps

Tongse for Erlenmeyer flasks

10-ml beakers (one per sample)

50-ml beakers (two per sample)

Pipets: 1- and 10-mi

125-ml separatory funnels (two per sample)

125-ml Erlenmeyer flasks (one per sample)

Ground-off Hirsch funnels: Coors 000A (one per sample)
Filter chimneys (one per sample)

Filter flasks (one per sample)

No, 42 Whatman filter circles: 7/8" diameter--washed with ethanol,

dried, and weighed _

No. 42 Whatman filter paper (9 cm)

2"  60° filter funnels (four per sample)

40-ml conical centrifuge tubes: Pyrex 8320 (14 per sample)
Wash bottle '

Steam bath

Hot plate
.Stirring rods.

48
PROCEDURE 11 (CONTINUED)

4. Preparation of Standard Beryllium Carrier

 

Dissolve 10. 62 gm of c.p. BeSO4- 4H20 -(Brush Beryllium Co.},
which has been dried overnight at 105°, in 500 ml of H,O. This gives a

solution containing 1.082 mg Be /ml (equivalent to 3. 00 mg BeO/ml).

Step 1.

Step 2.

Step 3.

SteB 4,

3. Procedure

Pipet exactly 10 ml of standard Be carrier.into a 40-ml
conical centrifuge tube and add an aliquot of the sample and

1 ml of conc. HC1l. Heat to boiling and add 0.5 ml of Fe
carrier. Bring the solution nearly to neutral by the dropwise
addition of 20% NaOH. Transfer the solution to another

40-ml centrifuge tube which contains sufficient 20% NaOH

to give the combined solution a 5% NaOH concentration. Stir
vigorously during the transfer. Heat on a steam bath for

5 min, centrifuge, transfer the supernate to a clean centrifuge
tube, and retain the Fe(OH)3 precipitate for Step 4.

Add 0.5 ml of Fe carrier to the supernate with constant,
vigorous stirring. Centrifuge, transfer the supernate to a
clean centrifuge tube, and retain the Fe(O]E-I)3 precipitate for
Step 4.

Neutralize the supernate by the dropwise addition of conc. HCI.
Make the solution ammoniacal with cone. NH 4O]E[. Heat for

5 min on a steam bath and then let the mixture stand for at
least 10 min, proceeding in the meantime with Step 4.

Combine the Fe(OH)3 preclpitates from Steps 41 and 2. Dissolve
the combined precipitate in a minimum of conc. HCl1l. Transfer
the solution into another centrifuge tube containing Buificienf
20% NaOH solution to givé to the combined solution a 5%

NaOH concentration, Heat on a eteam bath for 5 min.
Cenirifuge and transfer the supernate to a clean centrifuge
tube, discarding the precipitate (Note 1). Neutralize the
supernate with conc. HCIl and then make it ammoniacal with
conc., NH40H. Heat on a steam bath for 10 min.

49
Step 5.

Step 6.

Step 7.

Step 8.

Step 9.

SteB 10.

PROCEDURE 11 (CONTINUED)

Centrifuge the Be(OH)z precipitates formed in Steps 3 and 4.
Combine both supernates in a 125-ml Erlenmeyer flask

(Note 2}, Combine both precipitates by washing the smaller into
the larger. Stir to break up the precipitate and then centrifuge.
Transfer the wash liquor to the 125-ml flask above.

Dissolve the Be(OH)Z precipitate in a slight excess of conc.
HC1 and repeat Steps 1-5.

Dissolve the Be(OH)z precipitate in a minimum of 6 M HCI,
add ah additional milliliter of 6 M HCI1, and dilute to 10 ml
with HZO' Add 0.5 ml of Mo carrier and bubble in HZS for

5 min. Centrifuge and decant the supernate into a clean
centrifuge tube, discarding the precipitate. Heat the supernate
for 10 min on a steam bath, pass in HZS for 2 to 3 min, and
dilute to 20 ml with HZO' Centrifuge, transfer the supernate
to the clean centrifuge tube and discard the precipitate.

Heat the supernate to expel HZS' Add 0.5 ml of Sb carrier
and saturate with HZS' Centrifuge and decant the supernate
into a clean centrifuge tube, discarding the precipitate.

Heat the supernate to expel HZS and add 0.5 ml of Te (IV)
carrier. Boil and saturate with HZS’ centrifuge, and filter
through a No. 42 Whatman filter paper using a 2", 60° funnel
into another centrifuge tube (Note 3).

Heat the filtrate to expel HZS and then make ammoniacal with
conc., NH 4OH. Centrifuge and discard the supernate. Acidify
the Be(OH)Z precipitate with 5 m} of glacial HC2H302 and
evaporate the solution nearly to dryness, with constant
gtirring over a low flame. Add 5 ml of glacial HCZH302

and evaporate to dryness over a flame, being careful not to
let the temperature exceed 330°, the boiling point of basié
beryllium acetate. Let the tube cool to room ternperature and
extract the basic beryllium acetate with CHC13, using one

10- and three 5-ml portions of CHCl3 and centrifuging each
time before decanting the supernate into a 125-ml separatory
funnel. Retain the solid material in the céntrifuge tube.

60
Step 11.

Step 12.

Steg 13,

Step 14,

PROCEDURE 11 (CONTINUED)

Wash the CHC1 3 extract four times with 4-m1 portions of
I-IZO, transferring the wagh liquor to the centrifuge tube
containing the material which was not extracted by CHCls.
Filter the CHGI3 golution through dry No. 42 Whatman filter
paper into a clean, dry 50-ml beaker, using a 2", 60° filter
funnel. Evaporate the CHCl3 on a steam bath. While the
CHCl3 is being evaporated, proceed with Step 11.

Acidify the wash liquor and the CH_ClS-insoluble material
from Step 10 with cone. HC1. Precipitate Be(OH)2 by

the addition of conc. NH 4OI-I. Centrifuge. If an appreciable
quantity of Be(OH)z is formed, convert it to the basic acetate
as in Step 10 and repeat the CHC13 extraction, adding the
bagic acetate extracted to that obtained in Step 10.

Dissolve the basic acetate from the evaporated CHC1 3 extract
by heating with a minimum of conc. HNO,. JIf 1t is felt that
sufficient decontamination has been obtained, proceed
immediately to Step 14. However, it is necessary ordinarily
to proceed as in Step 13. ,

Transfer the solution to a clean centrifuge tube. Dilute
the I-I'NO-3 solution to 15 ml with HZO and precipitate Bv.e(OH)2
by the addition of conc. NH 4OH. Centrifuge and discard the
supernate. Repeat Steps 7-12,

. Evaporate the I:INO3 golution to 1 to 2 ml and transfer to a

10-ml beaker. Carefully continue heating (on a hot plate)

to dryness. Ignite for 1 hour at .250° in a muffle furnace.
Cool, slurry the BeO with 3 to 5 ml of absolute ethanol, and
pour onto a tared No. 42 Whatman filter circle in a filter
chimney -ground-off Hirach funnel set up which contains

10 ml of absolute ethanol. Permit the solid to settle evenly
on the filter circle (this requires about 10 min) before
applying suction. Dry the precipitate by pulling air through
the funnel for 2 to 5 min; then dry at 105° for 15 min. Cool
and weigh. Mount and gamma ~count in gcintillation counter
{Note 4). Be7 has only a 476-kev gamma ray.

51
PROCEDURE 11 (CONTINUED)

NOTES
An additional recovery of Be from the Fe(OH)'3 precipitated in Step 4
increases the chemical yield by about only 1 to 2%.
The supernates from the Be(OH)2 precipitations in Steps 3 and 4
are saved as a precautionary measure. If much Be(OH)Z appears
to have been lost at this stage, these supernates can be evaporated to
a small volume and made ammoniacal for further recovery of Be. A
small quantity of Be(OH) 2 is always formed by this treatment.
Steps 8 and 9 probably could be combined with Step 7, i.e., all
three carriers, Mo, Sb, and Te, could be added at the same time and
precipitated as sulfides.
Counting is begun immediately and is continued at intervals for a
period of at-lea'.st 53 days (one half-life of Be7). It is well to check
immediately for the presence of beta activity to determine whether
any impurity which is both a beta and a gamma emitter is contaminating

the Be7 and must be corrected far.

Addendum to Beryllium Procedure

 

If an appreciable amount of iron remains with the beryllium, i.e.,
enough to impart a yellow color to the Be(OH) 2 precipitate, just p.rior
to the basic acetate step, it is advisable to make an ether extraction
from 6 M HCI before proceeding. |
The solids from the acetic acid evaporation are heated to a temperature
of approximately 220° C to complete the formation of basic beryllium
acetate. About 30% of the Be is converted to the basic acetate at

118 to 120°; however, 95 to 97% is converted at 220° C. Care must
be exerdised to prevent the temperature from exceeding 330° and
thus decomposing the basic acetate alfeady formed. The final heating
is best accomplished in a constant temperature oil bath or under a
heat lamp." '

The final, BeO, aftér ignition at 500° is transferred directly to an
‘aluminum éou.fiting plate rather than beifig slurried with alcohol and

filtered. More reproducible results are obtained in this manner.

52
PROCEDURE 12

Separation of Beryllium from Fission Product Mixtures

Source - G. M. Iddings, in "Radiochemical Procedures in Use at the

University of California Radiation Laboratory (Livermore)',
University of California Radiation Laboratory Report UCRL. -4377
(1954).

Purification: From a 4-day old solution containing 1014 fissions and

Yield:

 

9

7
about 10° beta counts per minute, a sample of Be was

' obtained which showed a beta activity of about 7 ¢ /m.

About 70 per cent

Separation time: About six hours exclusive of ignition.

Step 1.

Step 2.

SteE 3.

Step 4

SteE 5.
Step 6.

Step 7. |

‘To an acid solution of mixzed activities, add 410 mg Be carrier

and about 5 mg of lanthanum carrier.

Make the solution ammoniacal. Centrifuge and wash
precipitate with dilute ammonia. Discard supernatant and
wash.

Add 10 ml 3 N NaOH to the precipitate. Digest for not more
than five minutes in a not water bath. Centrifuge. Repeat
leach with another 10 ml 3 N NaOH. Combine NaOH
supernatants. Discard residual La(OH)3.

Add ~ 5 mg Te+4 carrier to the NaOH solution. Add 5 drops

of a saturated solution of NaZS. Add ~ 15 ml of a saturated
solution of NH 4Cl. Centrifuge and wash Be(OH)z precipitate
twice with water. Discard supernatants.

Dissolve Be(OH)2 in 3 or 4 drops of c'bné. HCI, and add

~ 15'm] of a buffer solution of 0.5 N NaZSO3 and 1 N NaHSO3
(~pH 6). '

Transfer solution to a 60-m1, cylindrical, open-top,
separatory funnel (with stem detached immediately below the
stopcock). ' '

Add 30 ml of 0. 40 M TTA (thenoyltrifluoracetone) in benzene
and equilibrate phases for ten minutes by rapid stirring with

a motor-driven glass rod stirrer (paddle).

b3
Step 8.

Step 9.

Step 10.

Steg 11.

Step 12.

Step 13.

Step 14.

Step 15.

Step 16.

Step 17.
Step 18.

PROCEDURE 12 (CONTINUED)

Wash organic phase twice with ~ 15 ml of water allowing
three minutes for.each wash (to remove the sulfite). Wash
organic phase twice with ~ 15 ml of 8 N ANO 3 for five
minutes each wash (see Note 1).

Wash organic phase six times with ~ 42 ml of a sclution whose

composition is ~ 14 N HCl and 1 M H,SO, (11 ml conc.

HCI with 0.7 ml conc. H,SO,) allowing ten minutes for

each wash (see Note 2).

Add ~ 415 ml of a solution consisting of two parts conc.
formic acid and 4 part conc. HC1l. Agitate layers together
for 15 minutes. Repeat and combine aqueocus layers.

Make solution ammoniacal. Centrifuge the precipitate and
wash with water.

Add 10 ml of 3N NaOH and add Br, dropwise until solution
becomes yellow., Stir. Add a saturated solution of N aZS
dropwise until solution becomes colorless, then add 5 drops
excess (to keep any Te in solution when the pH 18 lowered

to 9 or 10 in the next step).

Add 10 ml of a saturated solution of NH 4Cl. Centrifuge
precipitate and wash with water.

Acidify with HCI to pH 3-4 (by adding ~ 20 ml of 0.1 N HCI).
Add ~ 5 mg Fe' 't carrier. Warm to ~ 60°C in water bath.
Add 1.5 ml of 5% 8-quinolinol in 2 N HAc. Add 5-10 ml of

2 E" NH 4Ac to bring golution to ~ pH 5. Let stand for five

minutes in 60°C bath, then cool to room temperature.
Filter through No. 42 Whatman paper. Discard precipitate.
(Separation of Be from Al, Pa, Zr, Nb and others.)

Make filtrate basic with NH,OH. Filter through No. 42
Whatman paper. Wash with 1% solution qf NH 4Ac.

Ignite to BeO for one hour at 1000°C.

Transfer to tared aluminum hat and weigh rapidly (BeO

is somewhat -h,ygroscopic.) Add a fe_w drops of Zapon
(diluted fourfold with ethyl acetate). |

64
PROCEDURE 12 (CONTINUED)
NOTES

Té+4 is slowly reduced to Te metal by the sulfite, and it is carried
along at the interface of the benzene-aqueous mixture. A 5-minute
wash with 8 N HNO, will oxidize finely divided Te metal to Tet?,
placing it in the acid layer. The paddle stirrer is necessary to
churn the two phases together very fapidly.

10 or 42 N HC1 will bring Np'* from 0.4 M TTA into the aqueous
phase. 12 N HCl with some sulfate will cause Zr, and some of Pa,
to be exiracted into the aqueous phase..

If very large amounts of protactinium are present initially, extra

 

gteps must be added to remove this activity. -

5b
N

10.

11,
12,

13.
14.

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