[en] The exothermic reactions of the type A + BC → AC + B between aluminium and βUO₃ αU₃O₈, αNa₂UO₄, Na₂U₂O₇, Na₆U₇O₂₄ and MUO₄ (where M Mg, Ca, Sr, or Ba) were studied using the techniques of differential thermal analysis (DTA), thermogravimetric evolved gas analysis (TGA-EGA), X-ray diffractometry, optical microscopy, and electron microprobe analysis. Two types of exothermic reactions were observed: the first type is a solid-state reaction occurring at the interface between particles in the compacted powders, beginning at or near the temperature at which the uranium compound undergoes either a first- or second-order transition. Only U₃O₈, UO₃ and those uranates having pseudo-hexagonal layers of [UO2(0sub(1.5))]^- groups undergo this first type of reaction. The second type of reaction is the reduction of the solid uranium compounds (all crystal structures) by liquid aluminium beginning at 800 to 900⁰C. (author)