Method for destructing oxalic acid in plutonium oxalate sediment mother solution

Abstract

The invention belongs to the technical field of spent fuel postprocessing, and discloses a method for destructing oxalic acid in a plutonium oxalate sediment mother solution. The method comprises the following steps that a direct-current power source capable of achieving periodic reverse is utilized for electrolyzing the plutonium oxalate sediment mother solution under the constant-voltage condition, and platinum electrodes or titanium-plated platinum electrodes are adopted as a cathode and an anode, wherein the reverse period of the direct-current power source is the time spent when the anode is passivated, and the constant voltage is an electrolytic oxidation decomposition peak potential value of the oxalic acid in the plutonium oxalate sediment mother solution. The method has the beneficial effects of being capable of effectively avoiding anode passivation and anode oxidation, and being high in electrolytic efficiency and high in electrolysis speed.

Description

technical field [0001] The invention belongs to the technical field of spent fuel reprocessing, and in particular relates to a method for destroying oxalic acid in plutonium oxalate precipitation mother liquor. Background technique [0002] In the process flow of spent fuel reprocessing, the tail end process of plutonium products is usually to add oxalic acid to the plutonium nitrate solution as a plutonium precipitant to make the plutonium into the form of plutonium oxalate precipitate, and the filtered precipitate is calcined at high temperature to form The final plutonium dioxide product, in which the filtered solution of the plutonium oxalate precipitate is called the plutonium oxalate precipitate mother liquor. In addition to about 0.05-0.1 mol / L oxalic acid and 2-3 mol / L nitric acid, the plutonium oxalate precipitation mother liquor also contains 50-200 mg / L trace plutonium. In order to maximize the recovery of plutonium in the reprocessing process, it is necessary to...

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Problems solved by technology

Qiao Jixin in my country studied the electrolytic destruction behavior of oxalic acid in the simulated plutonium oxalate precipitation mother liquor. The research results showed that the electrochemical oxidation method can achieve a oxalic acid destruction rate of more than 98%, but due to the CO produced during the anode destruction of oxalic acid 2 and O 2 , causing serious reversible passivation of the anode, and the current efficiency and electrolysis speed decrease accordingly. At this time, the stable electrolysis speed is usually ensured by increasing the electrolysis current density, but when the current density increases, in addition to aggravating the anode passivation, the cathode, The anode will also produce a large amount of hydrogen, oxygen and other side reactions, which will reduce the current efficiency and operation safety of the whole process, and the industrial application will be limited.

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