Abstract: A process for the production of uranium trioxide having a large specific surface by the thermal denitration of hydrated uranyl nitrate corresponding to the formula UO.sub.2 (NO.sub.3).sub.2 .multidot.xH.sub.2 O, in which 2.ltoreq.x.ltoreq.6, characterized in that, in a first stage, the said nitrate is treated in the form of a liquid at room temperature in the range from 160.degree. C. to 260.degree. C. until a solid phase containing at least 55% by weight of uranium is obtained and, in a second stage, the said solid phase is progressively heated to a temperature of at most 600.degree. C. at a heating rate of at most 1000.degree. C. per hour, and is kept at this temperature of at most 600.degree. C. until a second solid phase of UO.sub.3 having a large specific surface is obtained. The UO.sub.3 product produced has a specific surface of at least 10 m..sup.2 g.sup.-1.

Abstract: A method for preparing sodium chlorate comprises electrolyzing aqueous sodium chloride in the presence of at least one phosphorus-containing agent for complexing alkaline earth impurities, thereby advantageously extending the periods of uninterrupted satisfactory cell operation at substantially constant applied potential and facilitating the cleaning of electrodes between such periods.