Intensification of leaching of uranium concentrates
In work results of experiments on a lixiviation of a concentrate of uranium are explained. It is shown that transfer of process of a lixiviation to the pulsation device allows to intensify it, to reduce losses of uranium and hydrogen nitrate and to reduce process temperature. The pulsation device al...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2018
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| Цитувати: | Intensification of leaching of uranium concentrates / A.P. Mukhachov, Е.А. Kharytonova // Вопросы атомной науки и техники. — 2018. — № 1. — С. 169-172. — Бібліогр.: 5 назв. — англ. |
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Mukhachov, A.P. Kharytonova, Е.А. 2018-06-17T10:41:58Z 2018-06-17T10:41:58Z 2018 Intensification of leaching of uranium concentrates / A.P. Mukhachov, Е.А. Kharytonova // Вопросы атомной науки и техники. — 2018. — № 1. — С. 169-172. — Бібліогр.: 5 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/137376 669.822 In work results of experiments on a lixiviation of a concentrate of uranium are explained. It is shown that transfer of process of a lixiviation to the pulsation device allows to intensify it, to reduce losses of uranium and hydrogen nitrate and to reduce process temperature. The pulsation device allows to automate process and to provide positive control to them. Викладені результати експериментів з вилуговування концентрату урану в азотній кислоті. Показано, що пульсуюча колона дозволяє інтенсифікувати процес вилуговування урану, скоротити його втрати, витрати азотної кислоти і знизити температуру процесу. Пульсаційні колони дозволяють автоматизувати процес. Изложены результаты экспериментов по выщелачиванию концентрата урана в азотной кислоте. Показано, что пульсирующая колонна позволяет интенсифицировать процесс выщелачивания урана, сократить его потери, расход азотной кислоты и снизить температуру процесса. Пульсационные колонны позволяют автоматизировать процесс. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Физика и технология конструкционных материалов Intensification of leaching of uranium concentrates Інтенсифікація процесів вилуговування концентратів урану Интенсификация процессов выщелачивания концентратов урана Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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| title |
Intensification of leaching of uranium concentrates |
| spellingShingle |
Intensification of leaching of uranium concentrates Mukhachov, A.P. Kharytonova, Е.А. Физика и технология конструкционных материалов |
| title_short |
Intensification of leaching of uranium concentrates |
| title_full |
Intensification of leaching of uranium concentrates |
| title_fullStr |
Intensification of leaching of uranium concentrates |
| title_full_unstemmed |
Intensification of leaching of uranium concentrates |
| title_sort |
intensification of leaching of uranium concentrates |
| author |
Mukhachov, A.P. Kharytonova, Е.А. |
| author_facet |
Mukhachov, A.P. Kharytonova, Е.А. |
| topic |
Физика и технология конструкционных материалов |
| topic_facet |
Физика и технология конструкционных материалов |
| publishDate |
2018 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Інтенсифікація процесів вилуговування концентратів урану Интенсификация процессов выщелачивания концентратов урана |
| description |
In work results of experiments on a lixiviation of a concentrate of uranium are explained. It is shown that transfer of process of a lixiviation to the pulsation device allows to intensify it, to reduce losses of uranium and hydrogen nitrate and to reduce process temperature. The pulsation device allows to automate process and to provide positive control to them.
Викладені результати експериментів з вилуговування концентрату урану в азотній кислоті. Показано, що пульсуюча колона дозволяє інтенсифікувати процес вилуговування урану, скоротити його втрати, витрати азотної кислоти і знизити температуру процесу. Пульсаційні колони дозволяють автоматизувати процес.
Изложены результаты экспериментов по выщелачиванию концентрата урана в азотной кислоте. Показано, что пульсирующая колонна позволяет интенсифицировать процесс выщелачивания урана, сократить его потери, расход азотной кислоты и снизить температуру процесса. Пульсационные колонны позволяют автоматизировать процесс.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/137376 |
| citation_txt |
Intensification of leaching of uranium concentrates / A.P. Mukhachov, Е.А. Kharytonova // Вопросы атомной науки и техники. — 2018. — № 1. — С. 169-172. — Бібліогр.: 5 назв. — англ. |
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2025-11-25T21:04:07Z |
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2025-11-25T21:04:07Z |
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| fulltext |
ISSN 1562-6016. PASТ. 2018. №1(113), p. 169-172.
UDC 669.822
INTENSIFICATION OF LEACHING OF URANIUM CONCENTRATES
A.P. Mukhachov, Е.А. Kharytonova*
Chemical Technology of AISU, Kamyanskoye, Ukraine;
*Dneprovsky State Technical University, Kamyanskoye, Ukraine
E-mail: eah@ukr.net
In work results of experiments on a lixiviation of a concentrate of uranium are explained. It is shown that
transfer of process of a lixiviation to the pulsation device allows to intensify it, to reduce losses of uranium and
hydrogen nitrate and to reduce process temperature. The pulsation device allows to automate process and to provide
positive control to them.
INTRODUCTION
Chemical concentrates of rare metals are important
reprocessing products in hydrometallurgical processes;
their processing should be effective because of the high
cost. This is especially important for the production of
uranium, nuclear fuel for Ukrainian NPPs. The share of
the uranium extracted by a lixiviation method
continuously grows [1]. The concentrate of uranium is a
commercial product.
Processing of a concentrate is transfer of uranium to
a liquid phase. Uniform mixing is not ensured.
The theoretical foundations of the leaching process
and the problems of its intensification are discussed in
detail in [2], but the combination of physical effects
with leaching is not fully described.
The pulsation columns with a nozzle which are more
efficient devices for a lixiviation [3] allow to eliminate
the specified defects. They well fit into any operating
instrument scheme of production, are devices of ideal
replacement and allow to maintain the given time of a
lixiviation precisely.
Air and nozzles in plates increase a response time of
components in the pulsation column. The device does
not contain moving parts, is characterized by high
removal of a product from unit volume. In the course of
a lixiviation decrease in specific energy consumption is
reached [4, 5].
During pulsation, the liquid phase flows from the
plate to the plate, without lingering or creating a dense
layer. The presence of distribution properties of the
nozzle leads to the fact that the liquid phase and the
reagent are evenly distributed over the section and
height, which excludes the possibility of formation of
stagnant zones or “breakthroughs”.
The solids are leached in the surrounding liquid
medium and their entire surface is accessible for
contact.
The rate of the process is determined mainly by the
kinetics of internal diffusion and by the time necessary
for the reaction to proceed. Intensification of the
leaching process in the column is achieved by supplying
additional energy. The superposition of the vibrational
(reciprocating) motion on the volume of the liquid is
converted, due to the nozzle, and is evenly distributed
over the cross section.
The pulse generator is located outside the device, so
the cost of creating the installation is reduced, and the
process becomes easier and cheaper.
The pulsating column can operate in a direct-flow
and counter-current mode.
The purpose of the experiment was to determine the
possibility of deep leaching of uranium when replacing
the reactor with a pulsating column.
TECHNIQUE OF THE EXPERIMENT
The process of leaching of uranium was carried out
in a reactor with a stirrer and a pulsating column. The
nitric acid in the reactor was preheated to 70 °C. The
concentrate was periodically dosed into the acid so that
there was no ejection. The acid concentration was kept
constant. The process time was 1 hour.
Due to the reaction heat, the temperature in the
reactor rises to 90 °C. After the end of the process, the
product is filtered. The solution is sent for extraction to
purify uranium from impurities. The sediment is washed
and sent for disposal. The reaction products were
analyzed for uranium content.
According to the analysis, the dependence of the
degree of leaching on the rate of mixing, temperature,
nitric acid concentration, and the duration of the process
was determined. After studying the physico-chemical
parameters of the process, the physico-chemical
properties of the chemical concentrate were studied, and
the difficult-to-reveal classes that influenced extraction
were determined.
Taking into account the obtained data, a second
experiment was carried out on a pulsating column in a
direct-flow mode. For the leaching process in the
pulsation column, the following parameters were
selected: residual concentration – 100 g/l; contact time –
40 min; temperature – 45 °C; contact time – 40 min.
The acid enters the product level mirror in the
pulsating column and is evenly distributed. As a result,
the primary reaction proceeds over the entire surface,
causing a slight foaming.
The product was dosed through a calibrated opening.
The acid was administered continuously, its flow rate
was regulated by an acid meter.
The level in the column was maintained
automatically in the zone of intensive mixing, i.e. at the
first distribution plate. The residence time of the product
in the column can be controlled by the product flow
rate.
mailto:eah@ukr.net
RESULT AND DISCUSSION
The process of uranium leaching with nitric acid is
described by the reaction:
4 2 2 7 3
2 3 2 4 3 2
( ) 6
2 ( ) 2 3 .
NH U O HNO
UO NO NH NO H O
(1)
The process of leaching of the chemical concentrate,
as a rule, is realized in cascades of reactors. The number
of reactors is determined by the formula:
24n (Q τ) V , (2)
where n – number of devices; Q – daily productivity; τ-
duration of the process, hour; V – volume of the
apparatus, m
3
; η – is the filling factor of the apparatus.
The number of reactors in the cascade is no more
than 4. This does not exclude the “breakthrough” of
uranium-rich particles. The increase in the number of
devices is economically unprofitable. Equipment for
leaching must meet the following requirements:
– provide nitric acid access throughout the surface
of the solid particles;
– provide acid flow to the particle surface;
– evenly distribute the acid on the surface of the
plate;
– eliminate the possibility of formation of stagnant
zones;
– ensure continuity and stability of the leaching
process.
Reactor with a stirrer does not provide these
requirements.
Dependence of the degree of leaching on process
parameters is shown in Figs. 1–3.
From the data presented, it can be seen that an
increase in the speed of the stirrer from 100 to 500 rpm
significantly increases the degree of uranium recovery.
An increase in the reaction temperature from 50 to
95 °C sharply reduces the time of the process, but does
not affect the degree of uranium extraction. In the
solution, the leaching process lasts for 5…10 min. The
degree of uranium recovery in the reactor is 92…94%.
The residual concentration of nitric acid is
100…120 g/l.
As can be seen from the data in Tabl. 1, the main
class of chemical concentrates is 0.25 mm, large
particles break down into smaller fractions in which the
residual uranium content is approximately the same.
Fig. 1. Dependence of the degree of leaching on the
intensity of mixing: τ = const, c = const, t = const
Fig. 2. Dependence of the degree of leaching on
temperature and time, c = const, I = 200 rpm
Fig. 3. Dependence of the degree of leaching on the
concentration of acid
Table 1
Physico-chemical properties of uranium concentrate
To select the scheme of acid movement, you can
focus on the main class, 0.25 mm. The deposition speed
of smaller fractions is 0.3…0.5 m/h, therefore in the
pulsating column it is possible to organize only a direct
flow of the product and acid, and its specific surface
will be optimal.
The reaction time (τ) is determined by the ratio of
the volume of the apparatus (V) and the total volume of
the product (Qp) and acid (Qa) per unit time. It is
described by the equation:
τ = V/(Qp +Qa). (3)
The process of uranium leaching from the
concentrate was carried out on the pulsating column of
Fig. 4.
Comparative indexes of work of the pulsation
column and the reactor are given in Tabl. 2.
Process shortcomings of the reactor:
– the labor input and intermittence of process does
not allow to automate it and to increase efficiency;
– existence of a two-stage temperature schedule
which leads to intensive gas emission and foaming that
reduces efficiency of process;
Pulp until autopsy Pulp after autopsy
%
sieving
% of
uranium
Speed
deposition
m/hour
%
sieving
% of
uranium
0.1 71.6 360 – –
0.2 73.4 100 1.1 2.9
1.3 63.5 50 6.3 3.25
98.4 68.0 0.3 92.6 4.2
– when the stirrer (mechanism) rotates, a laminar
flow of liquid and solid particles is formed, which does
not allow to create a motion of the solution around
(relative to) a single particle;
– low extraction of uranium.
Speed of rotation of the mixing mechanism exceeds
the speed of rotation of a stream of solution that
increases thickness of a boundary layer. Local resistance
at the same time increases therefore the gradient of
strength of acid decreases and the small mass-transfer
coefficient is created that does not allow to increase
uranium extraction.
Table 2
Comparative indexes of work of the pulsation column and the reactor
Type of
apparatus
Schedule of
work
Volume of the
device, m
3
Temperature,
°С
Degree extractions of
uranium, %
Column Continuous 8 45.0 99.95
Reactor Periodic 40 98.0 94.0
During the stable work of the pulsation column the
following indicators were reached:
– concentration of uranium in solution –
180…200 g/l, in a solid phase – 3%;
– residual concentration of hydrogen nitrate –
100 g/l;
– the residual maintenance of solid – 9 g/l;
– uranium extraction degree – 99.95%.
Concentration of uranium:
– solution of 180…200 g/l;
– in the solid phase – 3%;
– the residual concentration of nitric acid is 100 g/l.
Residual solid content – 9 g/l.
The degree of extraction of uranium is 99.95%.
It should be noted that the content of uranium in a
solid phase after the pulsation column decreases from 3
to 0.05% that in the reactor cannot be reached.
СONCLUSIONS
Application of the pulsation column in the course of
a lixiviation of uranium allowed to reduce device
volume by 5 times.
Pulse column allowed to intensify the leaching
process, fully automate it, reduce the loss of reagents
and products, reduce the consumption of nitric acid and
improve working conditions. A real reduction in capital
and operating costs has been achieved.
The degree of uranium extraction in the continuous
process on the pulsating column increased to 99.95%.
The temperature schedule 90 °С at a lixiviation is
excluded. The temperature regime of 90 °C during
leaching is eliminated, which prevents the release of
nitrogen oxides and foaming.
REFERENCES
1. V.I. Golik. Innovative technologies for uranium
mining // Mountain Journal. 2009, N 2, p. 12-15.
2. A.S. Medvedev. Leaching and ways of its
intensification. M.: MISIS, 2005, p. 240.
3. SM. Karpachov et al. AU №175489 class 12D,
the IPC of the BII 1965 N 20.
4. S.M. Karpacheva et al. Development of the
pulsation equipment. M.: ”Atomizdat”, 1974, p. 256.
5. S.M. Karpachova et al. Pulsation equipment for
leaching and dissolution processes. M.: “Atomizdat”,
1974, p. 206-212.
Article received 30.11.2017
Fig. 4. Installation for a
lixiviation of uranium from a
concentrate:
1 – column; 2 – receiver;
3 – pulsation source; 4 – contour;
5 – the pulsation camera;
6 – level gage; 7– acidometer;
8 – compressor
ИНТЕНСИФИКАЦИЯ ПРОЦЕССОВ ВЫЩЕЛАЧИВАНИЯ КОНЦЕНТРАТОВ УРАНА
А.П. Мухачев, Е.А. Харитонова
Изложены результаты экспериментов по выщелачиванию концентрата урана в азотной кислоте.
Показано, что пульсирующая колонна позволяет интенсифицировать процесс выщелачивания урана,
сократить его потери, расход азотной кислоты и снизить температуру процесса. Пульсационные колонны
позволяют автоматизировать процесс.
ІНТЕНСИФІКАЦІЯ ПРОЦЕСІВ ВИЛУГОВУВАННЯ КОНЦЕНТРАТІВ УРАНУ
А.П. Мухачов, О.А. Харитонова
Викладені результати експериментів з вилуговування концентрату урану в азотній кислоті. Показано, що
пульсуюча колона дозволяє інтенсифікувати процес вилуговування урану, скоротити його втрати, витрати
азотної кислоти і знизити температуру процесу. Пульсаційні колони дозволяють автоматизувати процес.
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