High Quality Content by WIKIPEDIA articles! Yellowcake (also called urania) is a kind of uranium concentrate powder obtained from leach solutions, 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 has a pungent odour, is insoluble in water and contains about 80% uranium oxide, which melts at approximately 2878 °C. Although uranium is one of the densest metals on Earth, yellowcake is relatively light, with a density approximately that of elemental sulfur.