Redox states of uranium in samples of microlite and monazite

EES Authors
Publication Year
2016
Short Citation
Puchkova et al., 2016
Source
American Mineralogist
DOI
Abstract
By applying the method of chemical shifts of the uranium Lα1 and Lβ1 X-ray emission lines, the oxidation state of U has been determined in select samples of microlite and monazite. From the relative contents of U4+, U5+, and U6+ species, the oxygen coefficients have been calculated as a characteristic of U-oxidation rate. It is shown that the oxidation state of U is higher in the studied microlite than in monazite. Possible mechanisms of U oxidation in these two types of minerals are discussed, and it appears that the crystal structure of monazite plays an important role in stabilizing the U redox state. Spontaneous purification of the monazite structure from alien atoms, including U, may be possible via recrystallization of the α-recoil tracks. An explanation is suggested for intensive U oxidation in microlite and in other minerals of the pyrochlore group.
Research Track Category
Authors
Puchkova E.V., Bogdanov R.V., Gieré R.