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Study On The Adsorption And Curing Cs Of Hydrated Ceramics Based On Fly Ash And Zeolite

Posted on:2014-09-05Degree:MasterType:Thesis
Country:ChinaCandidate:H ShaoFull Text:PDF
GTID:2251330392972794Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
Radioactive Cs+is a long half-life of radionuclide which is very difficult to curing inthe nuclear industry of high level radioactive waste. Whilst the high-alkali radioactiveliquid waste is a by-product which was regarded as the high acidification radioactive liquidwaste. In this study, the fly ash as the raw material synthesized of NaA zeolite byhydrothermal method; The alkali activation of fly ash synthesized zeolite-like amorphoussilica gel. The gel, using as precursors, was preparation of the zeolite group hydratedceramic. And the synthesis of NaA zeolite and ceramic powders synthesized hydrated toinvestigate on the adsorption capacity of Cs+containing wastewater was explored. Thesimulation of high alkali doped cesium waste without curing amorphous silica-alumina gelhydrothermal synthesis in the body (hydrated ceramic) solid cesium ability and leachingresistance were mainly explored. By X-ray powder diffraction and scanning electronmicroscopy we studied the efficiency of precursor hydration properties and reactionmechanism by alkali and studied the Formation mechanism, structure characteristic and theinfluence of adsorption of cesium and related properties of alkali activated fly ashcementitious material. Phase composition of the hydrothermal curing body morphologyand microstructurewere solidified. Adsorption capacity of curing powder, ion leaching rateon Cs+substrates and curing compressive acid-fast ability were analysis by atomicabsorption spectrometer, universal testing machine. In this study we utilized of wasteresources which have rich fly ash directly to curing the Cs+under mild conditions, thestudy of solidified radioactive Cs+treatment has certain theoretical signification andpractical application value.The results show that the adsorption of Cs+performance NaA> of NaP1> analcime onzeolite,In298,313,333K temperatures, Zeolite NaA adsorption of Cs+Langmuirsaturation adsorption capacities were77.22mg/g,77.74mg/g,78.67mg/g.The adsorptioncapacity of Cs+is increased with temperatures rising, and the reaction is spontaneousthrough thermodynamic calculation of the Gibbs free energy(ΔGo), enthalpy(ΔHo)andentropy(ΔSo), Phase analysis shows that the solidified products:Effects of adding zeoliteNaA phase on the hydration ceramic crystal is not great, The final product is analcimewhether elevated temperature to180℃or increasing the hydrothermal time to24hours,Generation of zeolite in activator water glass modulus is low, that is easy to make the alkalicontent of fly ash gel, zeolite NaA and zeolite NaP1into analcime.We found that in different amount of addition liquid experiment:Liquid-solid ratio on the compressive strength of the hydrated ceramic solidified a great impact, Thecompressive strength increases with the ratio of liquid to solid, up to29.15MPa when theliquid to solid ratio is less than0.4, The compressive strength decreased significantly whenthe liquid to solid ratio is greater than0.5.In the alkaline environment synthetic zeolitebased on erosion resistance of solid acid is not a particularly good. Quality loss up to8.31%in a HAC-NaAC buffer solution medium in30days.In the anti leaching experiment, Cs+leaching is reduced with increasing oftemperatures and liquid dosage, It was also found that the curing of hydrated ceramic onthe synthesis of Sr2+is better than Cs+, so the study of hydrated ceramics based on zeoliteof curing Sr2+and Cs+are effectively.
Keywords/Search Tags:fly ash, hydration ceramic, cure, cesium, leach
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