What is an uranium dioxide?

Answer 1

Any rock or mineral containing economically recoverable quantities of Uranium compounds is a Uranium ore. These compounds are most commonly various oxides, silicates, titanates, phosphates, vanadates, arsenates, etc. of Uranium.

To get pure Uranium metal from the ore various processes can be used, but a basic outline of the steps goes something like:

1. Crush the ore to particles roughly the size of dust.
2. Mix with chemicals to dissolve the crushed ore and change the oxidation state of the Uranium separating it chemically from the ore molecules.
3. Mix with chemicals that cause the separated Uranium atoms to react with them, forming a precipitate (a Uranium oxide called yellowcake).
4. Filter the solution, the Uranium precipitate will stay in the filter while the rest passes through as waste. Wash in the filter to make sure none of the waste remains to contaminate the Uranium precipitate.
5. Dry the yellowcake powder.
6. Mix yellowcake with magnesium metal granules and heat red hot in a crucible. The mixture will ignite leaving Uranium metal in the bottom of the crucible and magnesium oxide slag on top.

Uranium is usually enriched first for reactors and bombs instead of just being converted to metal, also most power reactors use enriched yellowcake not the pure metal. To enrich Uranium the basic outline goes something like this:

1. Mix yellowcake with nitric acid, then ammonia, then hydrogen gas, then hydrofluoric acid, then fluorine gas to produce Uranium hexafluoride.
2. The Uranium hexafluoride it heated to become a gas in an enrichment plant (e.g. gaseous diffusion, gas centrifuge). The products are enriched Uranium hexafluoride (e.g. more Uranium-235) and depleted Uranium hexafluoride (e.g. less Uranium-235) from opposite ends of the plant.
3. The Uranium hexafluoride (of either or both types is converted back to yellowcake.

Answer 2

A chunk of rock or metal that has uranium mixed in with something else.

Answer 3

Uranium dioxide is the compound with the chemical formula UO2.