Yellow cake - Definition

Yellowcake (also known as urania and uranic oxide) is concentrated uranium oxide, obtained through the milling of uranium ore. It is usually represented by the formula U₃O₈. It is radioactive, forming a coarse powder which is insoluble in water and contain about 80% uranium oxide, and melts at approximately 2878°C. It is created by passing raw uranium ore through crushers and grinders to produce "pulped" ore. This is then bathed in sulphuric acid to leach out the uranium. Yellowcake is what remains after drying and filtering. The yellowcake produced by most modern mills is actually brown or black, not yellow; the name comes from the colour and texture of the concentrates produced by early mining operations.

Yellowcake is used in the preparation of fuel for nuclear reactors and in uranium enrichment, one of the essential steps for creating nuclear weapons. For uranium fuel preparation, it is processed into purified uranium dioxide (UO₂) for use in fuel rods. For uranium enrichment, it is converted to uranium hexafluoride gas (UF₆), for isotope separation by diffusion or centrifugal force to produce enriched uranium suitable for use in weapons and reactors.