Method for leaching uranium in radioactive alkali residues

Abstract

The invention provides a method for leaching uranium in radioactive alkali residues. The radioactive alkali residues are dry alkali residues which are finally formed after uranium-containing waste residues obtained through precipitation under alkaline conditions are filtered and forged at 800 DEG C in the uranium-containing wastewater treatment process. Multi-stage reflux dissolving leaching is adopted in the method, the method mainly includes the steps of alkali residue circulating dissolving, filtering, undissolved residue washing, filtering, undissolved residue first-stage leaching, clarifying, undissolved residue second-stage leaching, filtering, leached residue first-stage washing, clarifying, leached residue second-stage washing and filtering, leached tailings S6 are obtained after filtering, and the leached tailings S6 are subjected to neutralizing treatment and are conveyed to a disposal site. The method for leaching uranium in the radioactive alkali residues is simple in technical process, process solutions can be recycled, the uranium leaching rate is high, leaching cost is low, no wastewater is generated, and the content of uranium in the leached tailings S6 is lower than 0.1%.

Description

technical field [0001] The invention relates to the technical field of uranium leaching, in particular to a method for leaching uranium in radioactive alkali slag generated during the production and processing of nuclear fuel elements. Background technique [0002] During the production and processing of nuclear fuel elements, radioactive uranium-containing waste residues will be produced. Uranium-containing waste residues include alkali residues, trench mud, incineration ash, and insoluble residues. Among them, alkali residues are processed under alkaline conditions during the treatment of uranium-containing wastewater The uranium-containing waste slag obtained by precipitation is filtered and calcined at 800°C to form dry alkali slag; the trench mud is the material accumulated at the bottom of the uranium-containing wastewater storage tank after being dried and calcined at 800°C; the incineration ash is combustible radioactive waste Uranium-containing material is collected...

AI Technical Summary

Problems solved by technology

In view of the high content of uranium in radioactive alkali slag during the processing of uranium fuel elements, 235 U is characterized by high abundance, high recovery value, difficulty in leaching, and high leaching cost. The existing conventional treatment methods are two leaching technologies: concentrated acid aging method and secondary calcination method. 0.13%, the concentrated acid aging method will introduce sulfate radical impurities and produce new wastewater; the secondary calcination method consumes a lot of energy and takes a long time to process; supercritical CO is also used abroad 2 The leaching extraction process is used to leach uranium in the alkali slag, but the leaching process is complicated and the leaching cost is high, so it has not been applied so far

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