Radium of radium Curie used the residues after extraction of uranium from pitchblende. The uranium had been extracted by dissolution in sulfuric acid leaving radium sulfate, which is similar to barium sulfate but even less soluble in the residues. The residues also contained rather substantial amounts of barium sulfate which thus acted as a carrier for the radium sulfate. The first steps of the radium extraction process involved boiling with sodium hydroxide followed by hydrochloric acid treatment to remove as much as possible of other compounds. The remaining residue was then treated with sodium carbonate to convert the barium sulfate into
Uranium mining in Colorado granite. Although the zinc skarn and the pitchblende vein are exposed in the same workings, the pitchblende appears to have been deposited much later. Other vein-type uranium mines in the Front Range were the Fairday A. M. mine near Jamestown in Boulder County, and the Wright Lease mine near Ideledale in Jefferson County. The 70 mile long Uravan mineral belt is an arcuate zone of uranium-vanadium deposits in San Miguel, Montrose, and Mesa counties, Colorado, and Grand County, Utah. It was the area most productive of uranium in the United States in the early 20th century. The mineral belt includes