Difference between revisions of "Uranium"
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Uranium compounds, such as ammonium diuranate (aka "yellowcake") and uranium dioxide can also be purchased from United Nuclear. | Uranium compounds, such as ammonium diuranate (aka "yellowcake") and uranium dioxide can also be purchased from United Nuclear. | ||
| − | == | + | ==Isolation== |
Uranium metal can be prepared by reducing its compounds with a more reactive metal, such as [[calcium]]. The reduction should be performed under inert conditions, as uranium is pyrophoric. | Uranium metal can be prepared by reducing its compounds with a more reactive metal, such as [[calcium]]. The reduction should be performed under inert conditions, as uranium is pyrophoric. | ||
| − | Cody has made a video about extracting uranium metal from its ore, and was able to obtain a small amount of uranium metal.<ref>https://www.youtube.com/watch?v= | + | Cody has made a video about extracting uranium metal from its ore, and was able to obtain a small amount of uranium metal.<ref>https://www.youtube.com/watch?v=r6lZJuD6RIM</ref> |
==Projects== | ==Projects== | ||
Revision as of 15:53, 30 May 2019
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Uranium, U | ||||
| Allotropes | α-U (orthorhombic), β-U (tetragonal), γ-U (body-centered cubic) | ||||
| Appearance | Metallic gray | ||||
| Uranium in the periodic table | |||||
| |||||
| Atomic number | 92 | ||||
| Standard atomic weight (Ar) | 238.02891(3) | ||||
| Group, block | , f-block | ||||
| Period | period 7 | ||||
| Electron configuration | [Rn] 5f3 6d1 7s2 | ||||
per shell | 2, 8, 18, 32, 21, 9, 2 | ||||
| Physical properties | |||||
| Metallic gray | |||||
| Phase | Solid | ||||
| Melting point | 1405.3 K (1132.2 °C, 2070 °F) | ||||
| Boiling point | 4404 K (4131 °C, 7468 °F) | ||||
| Density near r.t. | 19.1 g/cm3 | ||||
| when liquid, at | 17.3 g/cm3 | ||||
| Heat of fusion | 9.14 kJ/mol | ||||
| Heat of | 417.1 kJ/mol | ||||
| Molar heat capacity | 27.665 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 6, 5, 4, 3, 2, 1 (a weakly basic oxide) | ||||
| Electronegativity | Pauling scale: 1.38 | ||||
| energies |
1st: 597.6 kJ/mol 2nd: 1420 kJ/mol | ||||
| Atomic radius | empirical: 156 pm | ||||
| Covalent radius | 196±7 pm | ||||
| Van der Waals radius | 186 pm | ||||
| Miscellanea | |||||
| Crystal structure | Orthorhombic | ||||
| Speed of sound thin rod | 3155 m/s (at 20 °C) | ||||
| Thermal expansion | 13.9 µm/(m·K) (at 25 °C) | ||||
| Thermal conductivity | 27.5 W/(m·K) | ||||
| Electrical resistivity | 0.28·10-3 Ω·m (at 0 °C) | ||||
| Magnetic ordering | Paramagnetic | ||||
| Young's modulus | 208 GPa | ||||
| Shear modulus | 111 GPa | ||||
| Bulk modulus | 100 GPa | ||||
| Poisson ratio | 0.23 | ||||
| Vickers hardness | 1960–2500 MPa | ||||
| Brinell hardness | 2350–3850 MPa | ||||
| CAS Registry Number | 7440-61-1 | ||||
| History | |||||
| Naming | After planet Uranus, itself named after Greek god of the sky Uranus | ||||
| Discovery | Martin Heinrich Klaproth (1789) | ||||
| First isolation | Eugène-Melchior Péligot (1841) | ||||
Uranium is a radioactive chemical element, member of the actinide group. It has the symbol U and atomic number 92. Because the uranium isotope Uranium-238 has a half-life of 4.468 billion years, the great majority (99.284%) of natural uranium is composed of this isotope. The uranium with a higher concentration of U-238 than the U-235 isotope (the fissile isotope) is commonly known as depleted uranium (DU).
Contents
Properties
Chemical
Uranium reacts with almost all non-metal elements and their compounds, its reactivity increases at higher temperatures. It will quickly tarnish in air, forming a dark layer of uranium dioxide. Hydrochloric and nitric acids dissolve uranium, but other non-oxidizing acids attack the element very slowly. When finely divided, it is very pyrophoric and can react with cold water.
As an actinide that displays the "quasi-group" property, uranium acts similarly to Group 6 metals: its most characteristic oxidation state is +6.
Physical
Uranium is a silvery-white metal in the actinide series of the periodic table. Its density is 18.9-19.1 g/cm3 about 70% higher than that of lead, but slightly lower than that of gold or tungsten.
Availability
Uranium is available for sale at chemical suppliers such as United Nuclear in its depleted form. In the US it may require a license[1] above certain quantity[2]. Boeing 747 planes produced between 1968 and 1981 used triangular DU counterweights, before they were replaced with tungsten ones.[3] GoodFellow sells uranium foil and wire.
Uranium compounds, such as ammonium diuranate (aka "yellowcake") and uranium dioxide can also be purchased from United Nuclear.
Isolation
Uranium metal can be prepared by reducing its compounds with a more reactive metal, such as calcium. The reduction should be performed under inert conditions, as uranium is pyrophoric.
Cody has made a video about extracting uranium metal from its ore, and was able to obtain a small amount of uranium metal.[4]
Projects
- Uranium glass
- Make uranium carbonate
- Element collecting
Handling
Safety
Natural and depleted uranium is weakly radioactive and poses little radiation risk. The metal and its compounds are toxic to the organism and should be handled with proper protection. Inhalation of powdered depleted uranium or uranium compounds is dangerous due to it's status as an alpha emitter. The main danger with uranium is not its radiation (it can safely be handled by hand), but its toxicity on ingestion.
Bulk DU is difficult to ignite, but finely divided uranium is highly pyrophoric.
Storage
As uranium will slowly react with the air, it should be stored under oil or in an inert container. Because of it's low radioactive hazard, depleted uranium does not require radiation shielding (the storage container walls will effectively absorb the weak alpha radiation).
Disposal
As uranium compounds are toxic and is a heavy metal, it is recommended to avoid dumping the compounds in the environment and should be taken to waste disposal facilities.
If the uranium was extracted from its natural ore taken from an area where the said ore can be easily collected, it's not entirely a bad idea to dispose of the ore wastes as well as uranium compounds residues in the said area, as the ore area is already naturally contaminated and the amount of ore waste is the same as the one you originally picked it up. Note that this method is not 100% sure and some research on its disposal is necessary.
References
- ↑ http://www.nrc.gov/reading-rm/doc-collections/cfr/part040/part040-0025.html
- ↑ http://www.nrc.gov/reading-rm/doc-collections/cfr/part040/part040-0013.html
- ↑ http://pbadupws.nrc.gov/docs/ML0321/ML032180089.pdf
- ↑ https://www.youtube.com/watch?v=r6lZJuD6RIM
