Uranium Mining and Milling cont'd - doe-hdbk-1113-98_reaffirm_2005

DOE-HDBK-1113-98

Module 102 The Nuclear Fuel Cycle

Lesson Plan

Instructor's Notes

Yellowcake contains 70-90% by weight of

uranium oxides. The leftover mill tailings are a

concern because they still contain some of the

uranium ore . Additional hazards exist due to the

chemicals added. It is estimated that the uranium

milling in the United States left approximately

138 million tons of mill tailings covering about

3,000 acres of land.

c. The yellowcake slurry is then purified by either

ion exchange or solvent extraction.

d. Following purification, the yellowcake slurry is

dried, forming a concentrated yellowcake

compound that contains 75 98 percent

uranium. The yellow color is caused by the

addition of leaching chemicals and their eventual

removal during the drying step. The final color

can range from yellow to orange to black

depending on the chemicals used and the drying

temperature.

The final color is a good indicator of solubility,

and thus of biological effects if uranium in this

form is taken into the body. Less soluble

uranium compounds tend both to remain in the

body longer and to be darker in color. More

soluble uranium compounds are removed from

the body more quickly by normal body

functions, and tend to be lighter in color.