what is yellowcake?

Yellowcake (also called urania or uranium oxide U₃O₈) is a kind of  uranium concentrate obtained from leaching ( the extraction of certain materials from a carrier int

o a liquid ), in an intermediate step in the processing of uranium ores. Yellowcake concentrates are prepared by various extraction and refining methods, depending on the types of ores.

Typically yellowcakes are obtained through the milling and chemical processing of uranium ore forming a coarse powder which is insoluble in water and contains about 80% uranium oxide, which melts at approximately 2878 °C. The name comes from the color and texture of concentrates produced by early mining operations;modern yellowcake is brown or black. Yellowcake is used in the preparation of fuel for nuclear reactors and may also be turned into enriched uranium suitable for use in weapons and reactors. It possess the density 2.055 g/cm³, solid . Nuclear power plants generate around 20 percent of the electricity produced in the United States

The basic aim of nuclear scientist is to increase the amount of u-235 atoms, a process  known as enrichment.In the enrichment process the yellow cake is dissolved in nitric acid and subjected to a series of chemical processes before being converted into gas -uranium hexafluoride  -by heating to above 64 degrees centigrade.

Uranium hexafluoride is corrosive and reactive and must be handled very carefully. Pipes and pumps at conversion plants are specially constructed from aluminium and nickel alloys. The gas is also kept away from oil and grease lubricants to avoid any inadvertent chemical reactions.

To know more  about the  the preparation of U₃O₈, called yellow cake ,visit http://www.chemcases.com/nuclear/nc-06.htm