La thorite métamicte : application de la résonance paramagnétique électronique (R. P. E.) à l'étude de sa recristallisation

Abstract

The E. P. R. enables the identification of three types of paramagnetic centers in the mineral : the centers F, Fe³⁺ tetrahedrically coordinated and Fe³⁺ in a ferromagnetic phase. The recrystallization of the mineral to huttonite is immediately preceded by a substitution of almost all the Fe³⁺ for thorium ; ultimately, these Fe³⁺ ions are eliminated through the formation of ferric oxide when the thermic treatment is carried out at a temperature higher than 1 200° C.