A kind of low temperature preparation method of strontium and cesium glass ceramic co-solidified body

Abstract

The invention discloses a low-temperature preparation method of a strontium and cesium glass ceramic co-solidified body, comprising: taking Ba(NO 3 ) 2 , Sr(NO 3 ) 2 , CsNO 3 , La(NO 3 ) 3 ·6H 2 O and Zr (NO 3 ) 2 ·5H 2 Add O into deionized water and stir until dissolved; add a chelating agent to the stirred solution, stir and chelate; add a gelling agent to the stirred chelated solution, and stir to obtain a transparent gel; the prepared transparent gel Drying, then heat treatment to obtain a black powder precursor; heat treatment of the black powder precursor to obtain a polycrystalline solidified body, the solidified body is mixed with a glass binder, and then pressed into a block by a hydraulic press, and the obtained block is calcined to make the polycrystalline solidified body. The crystalline solidified body powder is wrapped in a glass phase matrix to make a strontium and cesium glass-ceramic co-solidified body with high mechanical stability and low leaching resistance.

Description

technical field [0001] The invention relates to the technical field of solidification of radionuclide fission products, in particular to a low-temperature preparation method of a co-solidified body of strontium and cesium glass ceramics. Background technique [0002] Strontium and cesium are the two most important heat sources for the generation of radionuclide fission products in high-level waste liquids during the development and utilization of nuclear energy. The impact cannot be ignored. At present, the industrial treatment of strontium and cesium is mainly glass curing. Although its glass solidified body has the advantages of good resistance to β and γ radiation and strong tolerance, but glass is a metastable phase after all, with poor thermodynamic stability and resistance to α radiation. At low temperature, devitrification or crystallization is easy to occur, which leads to cracks in the solidified body, which increases the leaching rate of nuclides; in addition, a ...

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Problems solved by technology

However, most single-phase ceramic substrates have strong selectivity to radionuclides, and often can only contain a single and limited radionuclides, and cannot achieve simultaneous curing of strontium and cesium, and the cost of later industrial applications is high.

In addition, the preparation method of the ceramic solidified body is mainly a high-temperature solid-state reaction method. The process is to contact the solid-phase reactants with each other, and to prepare the target through the process of contact surface and phase region diffusion, migration, crystal nucleus formation and nucleus growth. The product generally has a high synthesis temperature (~1400-1500°C) and a long preparation time (>48h), and it is easy to form a heterogeneous phase during the synthesis process, which will cause the volatilization of cesium

For example, a master's degree thesis was published in 2005 (Zhao Yulong, China Institute of Atomic Energy, "Man-made rock solidification simulation 90Sr, 137Cs nuclide waste research"), the thesis uses the mineral phase combination of manganite, perovskite and rutile , conducted a simultaneous ceramic solidification study on strontium and cesium, and found that the solidified body has a dense structure and a low strontium and cesium leaching rate; but the hot-pressing sintering temperature of the ceramic solidified body is 1200 ° C, which will inevitably lead to the volatilization of a large amount of cesium

The Chinese invention patent application with publication number 102208223B in 2011 discloses a method for preparing a strontium-cesium co-solidified body. The method is based on modified ZSM-5A molecular sieve, and is absorbed in the solution, evaporated and dried, and calcined by temperature programming. Finally, strontium and cesium solidified polycrystals were obtained, which realized the simultaneous and low-temperature solidification of strontium and cesium, and solved the volatilization problem of cesium; Evaluation of leaching resistance of polycrystalline bonding, molding and curing nuclides

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