Improved Geopolymers for Encapsulation of Molten Salts from Thermal Treatment Processes

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F26722445%3A_____%2F24%3AN0000118" target="_blank" >RIV/26722445:_____/24:N0000118 - isvavai.cz</a>

Result on the web

<a href="https://www.djs.si/upload/nene/2023/proceedings/Contribution_517_final.pdf" target="_blank" >https://www.djs.si/upload/nene/2023/proceedings/Contribution_517_final.pdf</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Improved Geopolymers for Encapsulation of Molten Salts from Thermal Treatment Processes

Original language description

Organic waste is commonly generated during the operation of nuclear facilities and decommissioning. High prices for repositories force radioactive waste producers to lower the volume of organic radioactive waste for . Thermal treatment is one of the key routes for volume reduction, and Molten Salt Oxidation (MSO) is one of the potential processes. In the technology, the organic waste is dosed, together with an oxidising medium, under the surface of the molten salt, where flameless oxidation takes place, and non-combustible materials are trapped in the molten salts. For this study, the process for encapsulation of molten salt waste into an improved geopolymer matrix was conducted. The commercial geopolymer LK was encapsulated with 10 wt.% of volcanic tuff as a filler. The volcanic tuff was chosen for its zeolite richness for radionuclide trapping, good availability, and cost. The experiments were conducted by encapsulating 5, 10, and 15 wt.% of waste salts into the matrix. The mixture was cured under controlled conditions, and its physical and mechanical properties were tested by compressive strength and XRD analysis. Secondly, the molten salts were chemically enhanced for possible encapsulation. The molten salt waste mainly comprises Na2CO3 hydrates, which can cause sample instability and cracking. The chemical reaction with calcium hydroxide was conducted to form a more stable CaCO3. The resulting decantate had an average elemental composition of Na: Ca = 52.6:47.4. The resulting salt was encapsulated in a geopolymer with controlled conditions, and its physical and mechanical properties were tested for compressive strength and XRD analysis. The experiments were conducted with 5, 10, and 15 wt.% of enhanced waste added into the matrix. Compressive strength tests demonstrated satisfactory mechanical performance for future use, but more research is needed for possible waste load increase and sample stability.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

20401 - Chemical engineering (plants, products)

Project

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Continuities

R - Projekt Ramcoveho programu EK

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

NENE 2023 : 32nd International Conference Nuclear Energy for New Europe : proceedings : September 11-14, Portorož, Slovenia

ISBN

978-961-6207-56-0

ISSN

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e-ISSN

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Number of pages

9

Pages from-to

1-9

Publisher name

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Place of publication

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Event location

Portorož, Slovenia

Event date

Sep 11, 2027

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

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