Sulphatising roasting of a Greenlandic uranium ore, reactivity of minerals and recovery

• Main Author: Gamborg Hansen, J.K.
• Format: Book
• Language: English
• Published: Risø National Laboratory 1977
• Subjects: Risø-R-355; Risø-355; Risø report 355; Greenland; greenlandic
• Online Access: https://orbit.dtu.dk/en/publications/bb5e5f43-5ebd-4e2a-8768-48f6fe98e6b8; https://backend.orbit.dtu.dk/ws/files/53677452/ris_355.pdf

Uranium in the lujavrite ore from Kvanefjeld, South Greenland, can be solubilised by sulphatising roasting at 700 °C. The reactivity of various lujavrite minerals in the roasting process and the mechanism of the reaction were investigated by X-ray diffraction, optical microscopy, electron microprobe, thermal analysis, Mossbauer and infrared spectroscopy. Soluble sulphates are formed on the surface of the grains; an outer zone of the grains is transformed; usually a core remains unchanged. Variations in uranium recovery can be explained by variations in the contents of the uranium-bearing minerals, steenstrupine and uranium-containing pigmentary material (altered Zr containing silicate minerals), and in the degree of alteration of steenstrupine. Characterization of these minerals required many qualitative and a few quantitative electron microprobe analyses.