Method for enriching uranium and thorium from water phase by using cloud point extraction technology

Abstract

The invention discloses a method for enriching U (VI) or Th (IV) from a water phase by using cloud point extraction. The method adopts trialkyl phosphine oxide as extraction agent, TX-114 as surfactant and CnmimNTf2 hydrophobic ion liquid as additive to efficiently extract and separate out UO22+ or Th4+ from water solution under different conditions, wherein the water solution contains uranyl ions or thorium ions; and the ion strength of an extraction system is greater than or equal to 0.05 mol / L. The acidity range of the water phase adaptive to the method is large, so that the uranium and thorium ions can be remarkably extracted from the neutral condition to 2 mol / L HNO3. The cloud point extraction process is environment-friendly; and the method has wide prospects in the fields, such as uranyl enrichment and detection and the like.

Description

technical field [0001] The invention belongs to the field of nuclear fuel cycle, in particular to a method for enriching uranium and thorium from water phase by cloud point extraction. Background technique [0002] Uranium is the most important nuclear fuel in nuclear energy utilization at present, and thorium is a potential resource for nuclear energy utilization. At the same time, both are biologically pathogenic. Based on the application prospect and toxicity of uranium and thorium, it is very important to effectively enrich, separate and detect uranium and thorium in environmental and biological samples. [0003] Cloud point extraction (CPE) technology is a new type of separation and enrichment technology developed in recent years. It mainly uses the solubilization and phase separation of non-ionic surfactant solution to achieve the enrichment and separation of solutes. For non-ionic surfactant solutions, when the temperature is higher than a certain value, the solutio...

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Problems solved by technology

Acidic extractants such as dibenzoyl (DBM) and 1-(pyridylazo)-2-naphthol (PAN) are also used for cloud point extraction of UO 2 2+ 、Th 4+ Medium, but there is basically no effect under acidic conditions

In practical applications, such as nuclear fuel reprocessing, the acidity of the solution is often at a high level, which limits the application of cloud point extraction

Neutral extractant, such as tributyl phosphate (TBP), has better extraction effect under acidic conditions in conventional solvent extraction, but in cloud point extraction, effect is poor (Pashalidis I., et al., J.Radioanal .Nucl.Chem., 2010, 286, 461)

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