Electrodialysis device and method for separating nitric acid and acetic acid

Abstract

The invention relates to an electrodialysis device and method for separating nitric acid and acetic acid, and belongs to the technical field of nuclear fuel aftertreatment. The method comprises the following steps: under the action of a direct-current electric field, nitrate ions and acetate ions in feed liquid do directional movement towards an anode step by step under the selective permeability action of multiple layers of anion exchange membranes; nitrate ions with higher migration rate are enriched on the side close to the anode, and acetate ions with lower migration rate are enriched on the side close to the cathode. According to the device and the method provided by the invention, nitric acid / acetic acid is separated by utilizing the ionization degree difference of nitric acid and acetic acid in an aqueous solution and the ion migration speed difference under an external electric field, the separation process is simple and safe, the purity of a nitric acid product is high, and no other byproducts are generated.

Description

technical field [0001] The invention belongs to the technical field of nuclear fuel post-processing, in particular to an electrodialysis device and method for separating nitric acid and acetic acid. Background technique [0002] Nitric acid is an inorganic monobasic strong acid with strong oxidizing and corrosive properties. It is also an important chemical raw material and is widely used in industrial processes. At present, the nuclear fuel water reprocessing process at home and abroad is mainly completed in the nitric acid system. [0003] In recent years, as a new type of organic salt-free reagent, short-chain hydroxamic acid has attracted much attention in the application of spent fuel reprocessing process. In the Urex series process developed in the United States, acetohydroxamic acid (AHA) is used as a complexing agent. In the process, AHA is acidly hydrolyzed and radiolyzed to produce acetic acid, and the acetic acid and the remaining AHA from the reaction enter the ...

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Problems solved by technology

[0004] Existing methods for separating nitric acid / acetic acid mainly include rectification, acid-base neutralization and precipitation, extraction and separation, etc. The acid-base neutralization and precipitation method needs to introduce other ions and is likely to cause waste of resources; the method of destroying acetic acid requires high temperature Under high pressure, it is unfavorable for the post-treatment process; the crystallization method needs to be pre-treated to concentrate acetic acid; the AHA nitric acid aqueous solution will undergo an exothermic reaction when heated, and the pressure will increase, resulting in more complicated evaporation operations; The distribution coefficient and separation factor of acetic acid in nitric acid aqueous solution are not high, and organic waste liquid is produced at the same time

The separation process of these methods is complicated and the separation efficiency is not high, so it is necessary to provide a simple and efficient method to recover nitric acid to realize the recycling of nitric acid

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