From Wikipedia, the free encyclopedia
Chemical compound
Sodium diuranate
, also known as the yellow oxide of uranium, is an
inorganic chemical compound
with the
chemical formula
Na
2
U
2
O
7
. It is a
sodium
salt
of a
diuranate
anion. It forms a hexahydrate
Na
2
U
2
O
7
·6H
2
O
. Sodium diuranate is commonly referred to by the initials SDU.
[1]
Along with
ammonium diuranate
it was a component in early
yellowcakes
.
[2]
The ratio of the two compounds is determined by process conditions; however, yellowcake is now largely a mix of
uranium oxides
.
[3]
Preparation
[
edit
]
In the classical procedure for extracting uranium,
pitchblende
is broken up and mixed with
sulfuric
and
nitric acids
.
[4]
The uranium dissolves to form
uranyl sulfate
and sodium carbonate is added to precipitate impurities. If the uranium in the ore is in the tetravalent
oxidation state
, an oxidiser is added to oxidise it to the hexavalent oxidation state, and
sodium hydroxide
is then added to make the uranium
precipitate
as sodium diuranate.
[5]
The
alkaline
process of milling uranium ores involves precipitating sodium uranate from the pregnant
leaching
solution to produce the semi-refined product referred to as
yellowcake
.
[6]
These older methods of extracting uranium from its
uraninite ores
has been replaced in current practice by such procedures as
solvent extraction
,
ion exchange
, and
volatility
methods.
[7]
Sodium uranate may be obtained in the amorphous form by heating together urano-uranic oxide and
sodium chlorate
; or by heating sodium uranyl acetate or
carbonate
. The crystalline form is produced by adding the green oxide in small quantities to fused sodium chloride, or by dissolving the amorphous form in fused sodium chloride, and allowing crystallization to take place. It yields reddish-yellow to greenish-yellow prisms or leaflets.
Uses
[
edit
]
In the past it was widely used to produce
uranium glass
or vaseline glass,
[8]
the
sodium
salt dissolving easily into the
silica
matrix during the firing of the initial melt.
It was also used in
porcelain
dentures
to give them a
fluorescence
similar to that of natural
teeth
and once used in
pottery
to produce ivory to yellow shades in
glazes
.
[9]
It was added to these products as a mix with
cerium oxide
.
[10]
The final uranium composition was from 0.008 to 0.1% by weight uranium with an average of about 0.02%. The practice appears to have stopped in the late 1980s.
References
[
edit
]
- ^
Meredith, A. D.(2013). Modified Sodium Diuranate Process For the Recovery of Uranium From Uranium Hexafluoride Transport Cylinder Wash solution. (Doctoral dissertation). Retrieved from
http://scholarcommons.sc.edu/etd/2466
- ^
James A. Kent (27 May 2010).
Kent and Riegel's Handbook of Industrial Chemistry and Biotechnology
. Springer Science & Business Media. pp. 962?.
ISBN
978-0-387-27843-8
.
- ^
Hausen, D. M. (1998). "Characterizing and classifying uranium yellow cakes: A background".
JOM
.
50
(12): 45?47.
Bibcode
:
1998JOM....50l..45H
.
doi
:
10.1007/s11837-998-0307-5
.
ISSN
1047-4838
.
S2CID
97023067
.
- ^
"MQes Uranium Inc"
. Retrieved
2016-06-01
.
- ^
Purification of sodium diuranate
. Retrieved 2020-04-30
- ^
Method of precipitation of sodium diuranate
. Retrieved 2020-04-30
- ^
Gindler, J. E.(1962)
The Radiochemistry of Uranium
pp 39-235
- ^
Landa, E. R.; Disantis, D. J. (1993).
"A brief history of radioactive glassware"
.
Radiographics
.
13
(3): 697?699.
doi
:
10.1148/radiographics.13.3.8316677
.
PMID
8316677
.
- ^
"Uranium Containing Dentures (ca. 1960s, 1970s)"
. Retrieved
2016-06-01
.
- ^
Shcherbakov, Alexander B.; Reukov, Vladimir V.; Yakimansky, Alexander V.; Krasnopeeva, Elena L.; Ivanova, Olga S.; Popov, Anton L.; Ivanov, Vladimir K. (17 March 2021).
"CeO2 Nanoparticle-Containing Polymers for Biomedical Applications: A Review"
.
Polymers
.
13
(6): 924.
doi
:
10.3390/polym13060924
.
ISSN
2073-4360
.
PMC
8002506
.
PMID
33802821
.
External links
[
edit
]
|
---|
Inorganic
| Halides
| |
---|
Chalcogenides
| |
---|
Pnictogenides
| |
---|
Oxyhalides
| |
---|
Oxychalcogenides
| |
---|
Oxypnictogenides
| |
---|
Others
| |
---|
|
---|
Organic
| |
---|
|
---|
U(II)
| |
---|
U(III)
|
|
---|
U(IV)
| Organouranium(IV) compounds
| |
---|
|
---|
U(IV,V)
| |
---|
U(IV,VI)
| |
---|
U(V)
| |
---|
U(VI)
| |
---|
U(XII)
| |
---|