Production of technetium in molybdenum target on linac and modeling technetium distillation
Along with the traditional methods of molybdenum and technetium separation from target irradiated by an electron linear accelerator, the possibility of technetium stripping from aqueous solution has been considered. To achieve the required temperature we used phosphoric acid. Наряду с традиционными...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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| Cite this: | Production of technetium in molybdenum target on linac and modeling technetium distillation / A.I. Azarov, V.A. Bocharov, M.A. Dolzhek, A.S. Zadvorny, D.A. Kaplij, A.S. Lyashenko, V.A. Tsymbal // Вопросы атомной науки и техники. — 2014. — № 5. — С. 59-62. — Бібліогр.: 14 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860185075205799936 |
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| author | Azarov, A.I. Bocharov, V.A. Dolzhek, M.A. Zadvorny, A.S. Kaplij, D.A. Lyashenko, A.S. Tsymbal, V.A. |
| author_facet | Azarov, A.I. Bocharov, V.A. Dolzhek, M.A. Zadvorny, A.S. Kaplij, D.A. Lyashenko, A.S. Tsymbal, V.A. |
| citation_txt | Production of technetium in molybdenum target on linac and modeling technetium distillation / A.I. Azarov, V.A. Bocharov, M.A. Dolzhek, A.S. Zadvorny, D.A. Kaplij, A.S. Lyashenko, V.A. Tsymbal // Вопросы атомной науки и техники. — 2014. — № 5. — С. 59-62. — Бібліогр.: 14 назв. — англ. |
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| container_title | Вопросы атомной науки и техники |
| description | Along with the traditional methods of molybdenum and technetium separation from target irradiated by an electron linear accelerator, the possibility of technetium stripping from aqueous solution has been considered. To achieve the required temperature we used phosphoric acid.
Наряду с традиционными методами разделения молибдена и технеция из мишени, облучённой на линейном ускорителе электронов, рассмотрена возможность отгонки технеция из водного раствора. Для достижения необходимой температуры использована ортофосфорная кислота.
Нарівні з традіційними методами розділення молібдену і технецію з мішені, опроміненої на лінійному прискорювачі електронів, розглянута можливість відгонки технецію з водного розчину. Для досягнення необхідної температури використана ортофосфорна кислота.
|
| first_indexed | 2025-12-07T18:03:38Z |
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| fulltext |
PRODUCTION OF TECHNETIUM IN MOLYBDENUM
TARGET ON LINAC AND MODELING TECHNETIUM
DISTILLATION
A. I.Azarov, V.A.Bocharov∗, M.A.Dolzhek, A.S.Zadvorny, D.A.Kaplij,
A.S.Lyashenko, V.A.Tsymbal
National Science Center ”Kharkov Institute of Physics and Technology”, 61108, Kharkov, Ukraine
(Received June 24, 2014)
Along with the traditional methods of molybdenum and technetium separation from target irradiated by an electron
linear accelerator, the possibility of technetium stripping from aqueous solution has been considered. To achieve the
required temperature we used phosphoric acid.
PACS: 8255.+e
1. INTRODUCTION
In nuclear medicine 80% of radiopharmaceuticals la-
beled with technetium−99m [1] ( T1/2 = 6.02h,
Eγ = 140.5 keV ) are used in diagnostic studies. This
determines the importance of the problem.
2. PRODUCTION OF 99Mo
In production of 99Mo – the parent nucleus of tech-
netium – both molybdenum oxide and molybdenum
metal are used. The most common is reactor method
of 99Mo production comprising irradiation of 235U by
neutron flux and fission of uranium nucleus [2]. Fis-
sion products contain several percent of 99Mo. An-
other reactor way is irradiation of molybdenum ox-
ide (monoisotopic) with a neutron flux and produc-
tion of from 99Mo [2]. The use of the first reactor
method produces a lot of radioactive waste and re-
quires weapons-grade uranium giving a higher yield
of 99Mo. In the production of molybdenum in a cy-
clotron [3] the reaction 100Mo(p, np)99Mo is used.
Another reaction 100Mo(p, 2n)99mTc results in direct
production of 99mTc. A cyclotron method of 99Mo
production has not found industrial application be-
cause of the high energy costs.
An alternative to the aforementioned methods is
production of 99Mo on electron linear accelerator.
Despite the low specific activity of the target the price
of technetium dose may be lower than the one pro-
duced at the reactor. When using the linac it is desir-
able to use metal targets from enriched molybdenum.
The production goes according to equation: 100Mo
(γ, n) 99Mo → 99mTc (yield 89%) [4]. Earlier, the
same method was used in Davydov’s and Mareskin’s
works [5]. Although this alternative method has been
described in the literature, it has not yet been used
for the industrial production of technetium. Irradia-
tion of metallic molybdenum target of natural com-
position was produced by an electron accelerator with
maximum energy of 35MeV and average current of
250mA. Brake γ- quanta were produced in the tung-
sten converter 1mm thick. Maximum exposure time
was 26hours. We have used targets of natural metal-
lic molybdenum in the form of spacers with the di-
ameter 16 and 11mm and thickness of 0.2mm. The
spacers had a hole in the middle to be bound with
wire into bundles weighing ∼ 20...30 g. To separate
Mo and Tc targets should be dissolved.
3. DISSOLUTION OF Mo
Although the problem of metallic molybdenum dis-
solution has been solved in analytical chemistry, new
approaches appear. Until recently, the main pro-
cess was dissolution in acids. The monograph [6] has
systematized the existing literature quite thoroughly,
but it is metal sample weights from 0.2 to 5 g that we
are interested in. Nitric, sulfuric, hydrochloric acids
are used as reagents. For example, for a 0.5 g sample
of the metal 20...40ml of HNO3 are used (1:1), i.e.
the amount of acid exceeds stoichiometric one many
times. For example, for a 0.5 g sample of the metal
by Zelikman [7], molybdenum dissolves in nitric acid
or mixtures of sulfuric and nitric acids (molybdenum
cores on which the tungsten coil is wound are dis-
solved in the same manner) . Our task was to dis-
solve molybdenum target, drive off the excessive acid
and to dissolve the dry residue in alkali, thus obtain-
ing a solution suitable for the work of technetium
extraction generator. When dissolved in nitric acid,
molybdenum forms molybdic acid as a white gel that
prevents further dissolution of the metal. Since the
mass of metallic molybdenum target is 20...30 gr, its
∗Corresponding author E-mail address: bocharov@kipt.kharkov.ua
ISSN 1562-6016. PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2014, N5 (93).
Series: Nuclear Physics Investigations (63), p.59-62.
59
dissolution occurs differently than of 5 gr samples due
to the formation of a large volume of gel.
Studying the literature, we focused our attention
on molybdenil sulfate reagent (MoO2SO4), supplied
as 30% solution in sulfuric acid [8]. Apparently, there
is possibility to form other molybdenile salts, prob-
ably even molybdenile nitrate. In case of rapid ad-
dition of 5-fold excess to 30 g of molybdenum (com-
pared to stoichiometric ) of nitric acid (12M), dis-
solution of molybdenum takes place with formation
of a small volume of sediment (∼ 10ml) which does
not interfere with rapidly proceeding reaction ( in
less than 10min. ) By addition of nitric acid por-
tions of 10...15ml dissolution proceeds moderately
rapidly, but we cannot get rid of the sediment. In
this case the target is not fully dissolved. Molybde-
nile nitrate forms at substantial excess of nitric acid.
Given that the nitrate ion practically does not form
complex compounds, first of all, we paid attention
to the hydrofluoric and hydrochloric acids as an ad-
dition to the nitric acid in molybdenum dissolution.
We decided to test the efficacy of ligand, fluoride ion
introduced as hydrofluoric acid. We succeeded to dis-
solve 30 gr of molybdenum in mixture with 53ml of
56% nitric acid and 51ml of 40% hydrofluoric acid.
Consumption of nitric acid was almost stoichiometric.
After stripping of excess acids 30 g of molybdenum
was concentrated in 66ml solution.
The use of hydrofluoric acid is inconvenient, it re-
quires tupperware withstanding heat on a hotplate.
So we decided to use hydrochloric acid. To dis-
solve 27.28 gr of molybdenum, which took about
2.5hours, 54ml of nitric acid and 123ml of hy-
drochloric acid were used. In the middle of the disso-
lution process white precipitate appeared which dis-
solved after adding 20ml of hydrochloric acid. The
idea of molybdenile soluble salts formation proved
fruitful. We used target dissolution in a mixture (1:1)
of nitric and hydrochloric acids. Acid mixture was
used to reduce the amount of residue molybdic acid.
In the presence of hydrochloric acid, as we believe,
soluble molybdenile chloride forms. Dissolution of
heavy molybdenum targets (20 g or more) in a mix-
ture of hydrochloric and nitric acids 1:1 were per-
formed repeatedly, the targets completely dissolved
without solution splashing.
The authors of [9], have also used anodic dissolu-
tion of molybdenum in alkali. However, this device
is quite complicated for this. The irradiated target
was wrapped in nickel net for crumbling molybdenum
to contact with the positive electrode. The net was
attached to mixer (1000 rev/min). Thus, an accept-
able rate of dissolution was provided. In recent years
it has been proposed to dissolve metallic molybde-
num in hydrogen peroxide. Small targets about 0.2 g
were usually dissolved at moderate temperature [3].
Dissolution was carried out at temperature of ∼ 60◦,
adding 30...35% of peroxide portions, probably for
fear of uncontrolled decomposition of peroxide com-
pounds. In these conditions, our targets (20 g and
more) did not dissolve. Dissolving 30 g of molybde-
num, we added 15...20ml of water, a target glass was
heated to 60...80◦ to initiate the reaction, and then
brought to boiling. Peroxide was added in portions,
each of not more than 10ml to avoid splashing and
foaming of the solution. When dissolving, off molyb-
denum acids are formed, mainly diperoxide molyb-
denum (H2MoO6) and tetraperoxide molybdenum
(H2MoO8). These peracids contain oxygen chains
−O − O− instead of one atom of oxygen and as we
see, are soluble in water unlike molybdic acid. Du-
ration of 30 gr of Mo dissolution is 2hours and it
follows the equation:
Mo+ 7H2O2 = H2MoO8 + 6H2O.
As a result of dissolution we obtain yellow-orange
solution. With prolonged standing (24h) the solu-
tion solidifies, turning into yellow- orange translucent
mass. In the process of dissolution residue (presum-
ably from molybdic acid (H2MoO4)) can form, which
is dissolved in an excess of the peroxide.
Prior to learning of molybdenum dissolution in
peroxide, we have found out that molybdenum can
be dissolved in a mixture of nitric and ortho - phos-
phoric acids. Since the latter has a set of actions,
molybdic acid does not precipitate from solution of
phosphoric acid. We have conducted several experi-
ments on the dissolution of Mo in hot H3PO4 adding
nitric acid portions. Dissolution proceeds smoothly
and predictably. With molybdenum solution in phos-
phoric acid it would be unreasonable not to try to
strip Tc from the solution. However, we could not
immediately decide to strip the radioactive element -
technetium.
4. SIMULATION OF TECHNETIUM
STRIPPING
Rhenium has been selected as a model element.
Chemical properties of technetium and rhenium are
close. Boiling point of technetium oxide (VII) is 310◦,
rhenium oxide – 359◦. There is a link [10], which
indicates possible stripping from sulfuric acid. Tech-
netium is quantitatively stripped from the sulfuric
acid solution under the condition that the purge gas
does not contain reducing agents [11]. In our opinion,
the boiling point of sulfuric acid is not sufficient to
strip technetium, for 80% H2SO4 – 210◦, and it is in-
convenient to work with azeotropic mixture of 98.3%.
The temperature of the phosphoric acid can easily be
increased up to 350◦ (or even higher) without emis-
sion of harmful gases.
Solution of molybdenum oxide in phosphoric acid
and aliquot of the standard solution of rhenium was
placed into the Wurtz flask. Rhenium oxide was
stripped using an air cooler. To create the oxidiz-
ing atmosphere potassium permanganate was added.
Rhenium in the stripping was determined by emis-
sion method on ICP- spectrometer. It was shown
that rhenium was stripped quantitatively from solu-
tions of phosphoric acid. Subsequently, having learnt
molybdenum dissolution in hydrogen peroxide, we
added phosphoric acid to the solution and stripped
rhenium. It should be born in mind that rhenium is
60
contained in metallic molybdenum and in all molyb-
denum reagents.
5. CONCLUSIONS
Method of technetium (rhenium) stripping from an
aqueous solution of phosphoric acid may be an alter-
native to other methods for the separation of molyb-
denum and technetium:
- molybdenum sorption on aluminum oxide and
washing out the produced technetium with saline;
- adsorption of technetium on ion exchange resin;
- extraction of technetium from molybdate alkali
solution;
- sublimation of technetium from molybdenum ox-
ide melt.
The most common way (traditional) is produc-
tion of technetium on the sorption generator which
is a glass column with aluminum oxide of ∼ 2ml.
Molybdenum-99 deposits on aluminum oxide. Ac-
cumulating technetium is washed with saline. Sorp-
tion generators provide low productivity and are used
at a high specific activity of the irradiated mate-
rial ∼ 103 Ci/g. The advantage is that they can be
used directly in the hospital. Such devices are used
worldwide [12]. Technetium extraction in the extrac-
tion generator is influenced by various factors , the
main of which can reduce the effectiveness of extrac-
tion , it is a complex salt solution composition, pres-
ence of NO−
3 and poor contact between the aqueous
and organic phases. Sublimation method mentioned
above [1, 4, 13 ] is to dissolve a metal target, evapo-
rate the solution and preparation of molybdenum ox-
ide. Molybdenum oxide melts at 800...830◦ in a plat-
inum boat and accumulating technetium in the form
of heptaoxide is stripped in oxygen flow, however,
there is no industrial technology for this process at
the moment. In accelerated molybdenum-99 produc-
tion at low specific activity of technological solutions,
ion-exchange technetium extraction from solution of
complex ionic composition on chelate resin type and
technetium washing out from the resin with water or
saline is of interest. In this way molybdenum-99 tech-
nology using linac is being developed in Canada now
[14].
References
1. Isotopes, properites, receipt, application v. II: M:
”Fizmatlit”, 2005, 727 p. (in Russian).
2. G.V.Kiselev. Technology of receipt of radioactive
nuclides is in nuclear reactors. M.: ”Energoat-
omizdat”, 1990, 177 p. (in Russian).
3. K.M.Gagnon. Cyclotron production of
technetium-99m. Diss. Univer. of Alberta,
2012, 145 p.
4. R.G.Bennett, J.D.Christian, D.A.Petti,
W.K.Terry, S.B.Grover. A system of 99mTc
production based on distributed electron ac-
celerators and thermal separation.// Nuclear
technology. 1999, v. 126, p. 102-121.
5. M.G.Davydov, S.A.Mareskin. About possibility
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(in Russian).
6. R.Bok. Methods of decomposition are in analyt-
ical chemistry. M.: ”Khimia”, 1984, 428 p. (in
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7. A.N. Zelikman.Molibdenum. M.: ”Metallurgiya”,
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8. Chemical reagents and high-clean chemical mat-
ters. M.: ”Khimiya”, 1990, 687 p. (in Russian).
9. S.D.Chemerisov, A.Gelis, P.Tkac, D.L.Bowers,
V.Makarashvili, A.J. Bakel, J.T.Harvey,
G.E.Dale, G.F.Vandergrift. Argonne activi-
ties for the production of Mo-99 using linac
irradiation of Mo-100// RERTR 2010 -32nd
International Meeting on Reduced Enrichment
for Research and Test Reactors, October 10-14,
2010, Lisbon, Portugal, p. 1-7.
10. F.Cotton, G.Wilkinson. Advanced inorganic
chemistry. M.: ”Mir”, 1969, v. 3, 592 p. (in Rus-
sian).
11. L.L. Zajtseva, A.V.Velichko, I.V.Vinogradov.
Compounds of technetium and their application
domain // Results of scitech, series are Inor-
ganic chemistry. v. 9, M.: ”VINITI”, 1984, 120 p.
(in Russian).
12. I. Zolle. Performance and quality control of
the 99Mo/99mTc generator // Technetium-99m
pharmaceuticals, 2007, ”Springer”, p. 77-90.
13. V.I. Spicyn, A.F.Kuzina. Technetium. M.:
”Nauka”, 1981. 148 p. (in Russian).
14. Non-HEU production technologies for
molybdenum-99 and technetium-99m // Nu-
clear Energy Series No. NF- T- 5.4, IAEA,
Technical Reports. 2013, p. 30-31. www-
nds.iaea.org/photonuclear
61
ÍÀÐÀÁÎÒÊÀ ÒÅÕÍÅÖÈß Â ÌÎËÈÁÄÅÍÎÂÎÉ ÌÈØÅÍÈ ÍÀ ËÈÍÅÉÍÎÌ
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À.Ñ.Ëÿøåíêî, Â.À.Öûìáàë
Íàðÿäó ñ òðàäèöèîííûìè ìåòîäàìè ðàçäåëåíèÿ ìîëèáäåíà è òåõíåöèÿ èç ìèøåíè, îáëó÷¼ííîé íà ëè-
íåéíîì óñêîðèòåëå ýëåêòðîíîâ, ðàññìîòðåíà âîçìîæíîñòü îòãîíêè òåõíåöèÿ èç âîäíîãî ðàñòâîðà. Äëÿ
äîñòèæåíèÿ íåîáõîäèìîé òåìïåðàòóðû èñïîëüçîâàíà îðòîôîñôîðíàÿ êèñëîòà.
ÍÀÏÐÀÖÜÎÂÀÍÍß ÒÅÕÍÅÖIÞ Â ÌÎËIÁÄÅÍÎÂIÉ ÌIØÅÍI ÍÀ ËIÍIÉÍÎÌÓ
ÏÐÈÑÊÎÐÞÂÀ×I ÅËÅÊÒÐÎÍI ÒÀ ÌÎÄÅËÞÂÀÍÍß ÂIÄÃÎÍÊÈ ÒÅÕÍÅÖIÞ
Î. I.Àçàðîâ, Â.Î.Áî÷àðîâ, Ì.Î.Äîëæåê, À.Ñ.Çàäâîðíèé, Ä.Î.Êàïëié, Î.Ñ.Ëÿøåíêî,
Â.À.Öèìáàë
Íàðiâíi ç òðàäèöiéíèìè ìåòîäàìè ðîçäiëåííÿ ìîëiáäåíó i òåõíåöiþ ç ìiøåíi, îïðîìiíåíî¨ íà ëiíiéíîìó
ïðèñêîðþâà÷i åëåêòðîíiâ, ðîçãëÿíóòà ìîæëèâiñòü âiäãîíêè òåõíåöiþ ç âîäíîãî ðîç÷èíó. Äëÿ äîñÿãíåí-
íÿ íåîáõiäíî¨ òåìïåðàòóðè âèêîðèñòàíà îðòîôîñôîðíà êèñëîòà.
62
|
| id | nasplib_isofts_kiev_ua-123456789-80485 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T18:03:38Z |
| publishDate | 2014 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Azarov, A.I. Bocharov, V.A. Dolzhek, M.A. Zadvorny, A.S. Kaplij, D.A. Lyashenko, A.S. Tsymbal, V.A. 2015-04-18T14:13:58Z 2015-04-18T14:13:58Z 2014 Production of technetium in molybdenum target on linac and modeling technetium distillation / A.I. Azarov, V.A. Bocharov, M.A. Dolzhek, A.S. Zadvorny, D.A. Kaplij, A.S. Lyashenko, V.A. Tsymbal // Вопросы атомной науки и техники. — 2014. — № 5. — С. 59-62. — Бібліогр.: 14 назв. — англ. 1562-6016 PACS: 8255.+e https://nasplib.isofts.kiev.ua/handle/123456789/80485 Along with the traditional methods of molybdenum and technetium separation from target irradiated by an electron linear accelerator, the possibility of technetium stripping from aqueous solution has been considered. To achieve the required temperature we used phosphoric acid. Наряду с традиционными методами разделения молибдена и технеция из мишени, облучённой на линейном ускорителе электронов, рассмотрена возможность отгонки технеция из водного раствора. Для достижения необходимой температуры использована ортофосфорная кислота. Нарівні з традіційними методами розділення молібдену і технецію з мішені, опроміненої на лінійному прискорювачі електронів, розглянута можливість відгонки технецію з водного розчину. Для досягнення необхідної температури використана ортофосфорна кислота. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Ядерно-физические методы и обработка данных Production of technetium in molybdenum target on linac and modeling technetium distillation Наработка технеция в молибденовой мишени на линейном ускорителе электронов и моделирование отгонки технеция Напрацьовання технецію в молібденовій мішені на лінійному прискорювачі електронів та моделювання відгонки технецію Article published earlier |
| spellingShingle | Production of technetium in molybdenum target on linac and modeling technetium distillation Azarov, A.I. Bocharov, V.A. Dolzhek, M.A. Zadvorny, A.S. Kaplij, D.A. Lyashenko, A.S. Tsymbal, V.A. Ядерно-физические методы и обработка данных |
| title | Production of technetium in molybdenum target on linac and modeling technetium distillation |
| title_alt | Наработка технеция в молибденовой мишени на линейном ускорителе электронов и моделирование отгонки технеция Напрацьовання технецію в молібденовій мішені на лінійному прискорювачі електронів та моделювання відгонки технецію |
| title_full | Production of technetium in molybdenum target on linac and modeling technetium distillation |
| title_fullStr | Production of technetium in molybdenum target on linac and modeling technetium distillation |
| title_full_unstemmed | Production of technetium in molybdenum target on linac and modeling technetium distillation |
| title_short | Production of technetium in molybdenum target on linac and modeling technetium distillation |
| title_sort | production of technetium in molybdenum target on linac and modeling technetium distillation |
| topic | Ядерно-физические методы и обработка данных |
| topic_facet | Ядерно-физические методы и обработка данных |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/80485 |
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