Ion Chromatography Analysis Method of Trace Oxalic Acid in High Concentration Nitric Acid Solution

Abstract

The invention belongs to the technical field of post-processing of nuclear fuel, and in particular relates to an ion chromatography analysis method for trace amounts of oxalic acid in a high-concentration nitric acid solution. Instrument detection and analysis, wherein, before the above-mentioned washing step, solid NaHCO3 is used to pretreat the destroyed plutonium (IV) oxalate precipitation mother liquor, so that the pH value is 6 to 8; the composition of the eluent system is: Na2CO3, NaHCO3 and H3BO3, wherein the concentration of Na2CO3 is 2-10mmol / L, the concentration of NaHCO3 is 2-10mmol / L, and the concentration of H3BO3 is 2-10mmol / L. The ion chromatography analysis method can accurately analyze trace amounts of oxalic acid in high-concentration nitric acid solution.

Description

Ion Chromatography Analysis Method of Trace Oxalic Acid in High Concentration Nitric Acid Solution technical field The invention belongs to the technical field of post-treatment of nuclear fuel, and in particular relates to an ion chromatographic analysis method for trace amounts of oxalic acid in a high-concentration nitric acid solution. Background technique Many reprocessing plants in the world today mostly use oxalic acid precipitation to convert plutonium nitrate solution into solid plutonium dioxide that is more conducive to preservation. In order to make the conversion rate of plutonium as high as possible, the amount of oxalic acid is about 10g / L (0.1mol / L) in excess of oxalic acid in the feed solution on the basis of satisfying the stoichiometric ratio of plutonium nitrate precipitation. The washing liquid produced in the precipitation process is combined with the filtrate to form the plutonium(IV) oxalate precipitation mother liquor. Since the precipitation moth...

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Problems solved by technology

Experiments have shown that this eluent system cannot achieve complete separation between high-concentration nitric acid and trace amounts of oxalic acid, and the actual application effect is not good.

For the destroyed precipitation mother liquor contains ~10-4mol / L oxalic acid and 2-3mol / L nitric acid, the concentration can differ by up to 104 times, and the conventional eluent system cannot achieve the separation of the two

High concentrations of nitric acid have a great impact on the analysis results, making it impossible to accurately analyze the concentration of trace oxalic acid in the sample

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