A kind of analysis method of rare earth element content in thorium tetrafluoride

Abstract

The invention relates to a method for analyzing the content of rare earth elements in thorium tetrafluoride. The method comprises the following steps: dissolving thorium tetrafluoride powder in an ammonium carbonate solution to obtain a first solution; adding hydrogen peroxide into the first solution, and centrifuging the obtained solution to obtain a water phase and a solid phase; adding an acid into the water phase, heating the water phase to obtain a second solution free from fluorine and ammonium, and dissolving the solid phase in nitric acid to obtain a third solution; mixing the second solution with the third solution to obtain a dissolution solution, and diluting the dissolution solution with nitric acid to obtain an introduction sample; repeating above steps without adding the thorium tetrafluoride powder to obtain a blank solution; transferring a plurality of parts of the dissolution solution, and respectively adding different amounts of a rare earth mixed substance solution to obtain multiple standard substance added solutions; and determining the rare earth elements in the blank solution, the standard substance added solutions and the introduction sample by using an inductively coupled plasma mass spectrometer. The method for analyzing the content of rare earth elements in thorium tetrafluoride can be used to highly-efficiently and accurately determine the content of rare earth elements in thorium tetrafluoride.

Description

technical field [0001] The invention relates to a chemical detection method, in particular to an analysis method for the content of rare earth elements in thorium tetrafluoride. Background technique [0002] Thorium tetrafluoride is an important fuel for liquid fuel thorium-based nuclear reactors. The detection of impurity content in thorium fuel is an important part of the quality control of thorium fuel. In nature, thorium rarely exists as an independent mineral, and mostly coexists with rare earth minerals, and rare earth elements, especially Sm, Eu, Gd and Dy, are elements with high thermal neutron absorption cross-sections, and their content directly affects the nuclear fuel. Therefore, it is necessary to accurately determine the content of rare earth elements in thorium tetrafluoride powder. [0003] The analysis of impurities in thorium tetrafluoride powder requires sample pretreatment, the first step of which is the dissolution of thorium tetrafluoride powder. Due...

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Problems solved by technology

Thorium tetrafluoride can be dissolved in hot concentrated sulfuric acid, but due to the danger of concentrated sulfuric acid, this dissolution method is not suitable for daily operation

Thorium tetrafluoride can be dissolved in hot aluminum nitrate solution, but the total dissolved solids (TDS) in aluminum nitrate solution is too high for instrumental analysis

Thorium tetrafluoride can also be dissolved in hot ammonium carbonate solution, but it is an alkaline solution, not suitable for direct analysis on the machine, therefore, it is necessary to convert the alkaline solution into an acidic solution

ICP-AES has a lot of spectral interference, and thorium is a multi-spectral element with very dense spectral lines, which interferes with the determination of many elements. However, if the thorium element is separated in advance, the analysis process will be too long

ICP-MS has the advantages of high sensitivity, wide linear range, good anti-interference ability, simple spectral lines, fast analysis speed and simultaneous multi-element, qualitative and quantitative analysis; but the existence of excess thorium will cause matrix effect problems

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