Method for rapidly oxidizing oxalic acid

The invention belongs to the technical field of spent fuel post-treatment of plutonium tail ends, and particularly relates to a method for rapidly oxidizing oxalic acid. Nitrous acid is produced in a manner of quantitatively introducing nitrogen oxide into feed liquid. The characteristic that the oxidation power of nitrous acid in a dilute solution is stronger than that of nitric acid is utilized, oxidation of oxalic acid is accelerated, the addition of potassium permanganate and high-temperature heat preservation conditions are not changed, and the original catalytic action of divalent manganese is still kept on the premise that the introduction amount of metal ions is not increased, so that the reaction rate is maximized. Various parameters are determined through a control variable method experiment, and the parameters should meet engineering application requirements. In consideration of adaptability of engineering application of a post-treatment plant, existing parameters are adopted: the flow rate of nitr