Several uranium complex ions have been found to be stable over a wide range of pH, temperature, and pressure. At 25 degrees C and in neutral solutions uranyl complexes of carbonate, fluoride, and hydroxide remain in solution at concentration values between 10 (super -5) M and 10 (super -3) M. At elevated temperatures (215 degrees C) the solubility of these ions at pH 7 is still above 10 (super -5) M.At 25 degrees C the above mentioned ions will react with a reducing agent (H 2 S) at pH 7 to form pitchblende of small crystallite size. A similar reaction proceeds at elevated temperatures (215 degrees C) and pH 7, but the pitchblende precipitates with larger crystallite dimensions.The uranous complex ions are relatively unstable. Solutions of uranous hydroxide precipitate a small amount of pitchblende at 25 degrees C. At elevated temperatures (215 degrees C) all of the uranium in solution converts to well crystallized pitchblende.

First Page Preview

First page PDF preview
You do not currently have access to this article.