Nuclear Chemical Effects in the Paragenetic Mineral Association Based on Polycrase

A natural polymineral compound in which the major uranium-containing mineral is polycrase (Ti- Ta-niobate) described by the formula АВ 2 О 6 was chosen as a model for studying the behavior of recoil atoms produced by α-decay of actinides. Polycrase, despite its metamict structure, is characterized b...

Full description

Saved in:
Bibliographic Details
Published in:Radiochemistry (New York, N.Y.) N.Y.), 2018, Vol.60 (1), p.79-91
Main Authors: Hosseinpour Khanmiri, M., Bogdanov, R. V.
Format: Article
Language:English
Subjects:
Actinides
Atomic structure
Chemical effects
Chemistry
Chemistry and Materials Science
Chemistry/Food Science
Leaching
Niobates
Nuclear Chemistry
Oxidation
Recoil atoms
Uranium
Zircon
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A natural polymineral compound in which the major uranium-containing mineral is polycrase (Ti- Ta-niobate) described by the formula АВ 2 О 6 was chosen as a model for studying the behavior of recoil atoms produced by α-decay of actinides. Polycrase, despite its metamict structure, is characterized by the following features distinguishing it from Ti-Ta-niobates of the formula А 2 В 2 О 7 (pyrochlore and betafite): (1) 1/3 of uranium atoms preserve the initial valence state, U(IV); (2) the U(IV) fraction is characterized by the isotope activity ratio AR( 234 U/ 238 U) close to that at secular equilibrium; (3) the uranium atoms that underwent oxidation “memorize” their radiogenic origin; as a result, the AR( 234 U/ 238 U) ratio in the U(VI) fraction is 0.90, and in the most altered part of the mineral it decreases to 0.77; (4) the parent uranium is relatively stable in the metamict structure of polycrase: The half-leaching time for 238 U atoms is 2 times longer than that in betafite, zircon, or sphene.
ISSN:1066-3622
1608-3288
DOI:10.1134/S1066362218010137