Solid state reactions of potassium uranates with ammonium sulphates

Solid state reactions of potassium uranates with (NH4)2SO4 were studied with a view to understand the nature of the reaction products formed at different temperatures. The hexavalent uranates K2U2O7 and K2U4O13 formed double sulphates of U(VI) at 380 degC, whereas pentavalent KUO3 and mixed valent K2U4O12 reacted at the above temperature to form mixtures of potassium uranium double sulphates containing both U(IV) and U(VI). Thermal, x-ray and chemical methods were used to identify and characterise the products. (author). 4 refs., 1 fig., 1 tab