Preparation method of high-purity thorium nitrate

Abstract

The invention provides a preparation method of high-purity thorium nitrate. The preparation method comprises the steps that HNO3 and NaNO3 are used as salting-out agents for allocating a Th(NO3)4 solution to form a mixed solution, and a P350-sulfonated kerosene organic phase is used for extracting the mixed solution; a NaNO3 solution is adopted for washing the obtained organic phase loaded with Th; and a fluorine-containing water solution is adopted for reversely extracting the washed organic phase loaded with Th. The process has the advantages that when high-purity water is adopted for thorium reverse extraction, F<-> in an added HF or NaF solution can be easily coordinated with Th<4+> to form [ThFx]<4>-x, so that reverse extraction of a P350 system with Th<4+> loaded is promoted, and the reverse extraction rate of thorium can be improved; and the product quality can reach the standards that ThO2 / Th(NO3)4.6H2O is larger than or equal to 46%, and the ThO2 purity is larger than 99.9995%.

Description

technical field [0001] The invention relates to a preparation method of high-purity thorium nitrate, in particular to the process of purifying thorium nitrate by means of extraction and separation, and belongs to the field of material preparation. Background technique [0002] Monazite is one of the important rare earth ores. It also contains a considerable amount of uranium, which is a nuclear fuel urgently needed by the country at present, and contains a high content of thorium, which is a valuable resource for future important nuclear fuels. [0003] At present, the monazite mineral content in the industrially obtained concentrate can reach more than 95%, and the rest are associated minerals such as zircon sand, xenotime, and ilmenite. The caustic soda decomposition method is generally adopted in the industry to process monazite concentrate, ["Rare Earth", the first edition of the first volume, Metallurgical Industry Press 1978, P221-237), the preferential dissolution sla...

AI Technical Summary

Problems solved by technology

[0005] In the step of back-extracting thorium in the process of separating U, Th, RE and Fe in the above process P350-hydrochloric acid system, water is generally used to back-extract thorium in the organic phase. Since the complexing ability of water and thorium is weak, the During the stripping process, the stripping of thorium in the organic phase is not completed, and at the same time, the number of stripping stages needs to be increased, which affects the extraction capacity of the circulating organic phase. The method of stripping, by adding HF or NaF is beneficial to improve the stripping rate of thorium, the F in the solution - Easy with Th 4+ Coordination formation [ThF x ] 4-x , thereby promoting Th 4+ The back-extraction of fluorine ions can improve the yield of thorium, and the high-purity thorium nitrate obtained after fluoride ion back-extraction can be applied to thorium-based molten salt reactors