Solidification/stabilization of fly ash contaminated with radiocaesium into geopolymers

Rezbárik, Šimon; Vavrincová, Lenka; Valica, Martin; Adamcová, Vanda; Sekely, Stanislav; Rezbárik, Ján; Horník, Miroslav

Solidification/stabilization of fly ash contaminated with radiocaesium into geopolymers

Scientific Review Engineering and Environmental Sciences

Volume 34 (2025): Issue 1 (March 2025)

By: Šimon Rezbárik, Lenka Vavrincová, Martin Valica

, Vanda Adamcová

, Stanislav Sekely, Ján Rezbárik and Miroslav Horník

Open Access

|Mar 2025

Figures & Tables

Changes in pH (A), conductivity (B), and 137Cs activity (C) values in deionized water released from prepared geopolymer waste forms with different fly ash contents (5 wt.%, 10 wt.%, 20 wt.%, and 40 wt.%). After each measurement, the deionized water was replaced with fresh water and the duration of exposure of the geopolymer waste form sample from the beginning of the leachability test was as follows: 1st measurement – after 2 h of exposure; 2nd measurement – after 4 h; 3rd measurement – after 7 h; 4th measurement – after 24 h; 5th measurement – after 48 h; 6th measurement – after 72 h; 7th measurement – after 96 h; 8th measurement – after 120 h of exposure. The values represent the arithmetic means and the error bars describe the standard deviation of three independent experiments
Source: own work. — Changes in pH (A), conductivity (B), and 137Cs activity (C) values in deionized water released from prepared geopolymer waste forms with different fly ash contents (5 wt.%, 10 wt.%, 20 wt.%, and 40 wt.%). After each measurement, the deionized water was replaced with fresh water and the duration of exposure of the geopolymer waste form sample from the beginning of the leachability test was as follows: 1st measurement – after 2 h of exposure; 2nd measurement – after 4 h; 3rd measurement – after 7 h; 4th measurement – after 24 h; 5th measurement – after 48 h; 6th measurement – after 72 h; 7th measurement – after 96 h; 8th measurement – after 120 h of exposure. The values represent the arithmetic means and the error bars describe the standard deviation of three independent experiments Source: own work.

Compressive strength measured for prepared geopolymer waste forms with different fly ash contents. The values represent the arithmetic means and the error bars describe the standard deviation of three independent experiments
Source: own work. — Compressive strength measured for prepared geopolymer waste forms with different fly ash contents. The values represent the arithmetic means and the error bars describe the standard deviation of three independent experiments Source: own work.

Proportion of oxides in fly ash sample originating from Vojany TPP (Slovak Republic)

Oxide	Weight proportion [%; d.w.]	Measurement uncertainty [%]	Analytical method
K₂O	2.01	10	F-AAS
P₂O₂	0.53	15	ICP-OES
Al₂O₃	20.2	15	ICP-OES
MgO	1.74	15	ICP-OES
SiO₂	39.5	not determined	gravimetry
MnO	0.12	not determined	ICP-OES
Na₂O	0.66	10	F-AAS
TiO₂	0.81	not determined	ICP-OES
CaO	14.1	15	ICP-OES
Fe₂O₃	6.78	20	ICP-OES

Physico-chemical and geometric characteristics of prepared geopolymer waste forms

Proportion of fly ash [%]	Average weight of samples [g]	Average height of samples [cm]	Average sample volume [cm³]	Average surface area of samples [cm²]	Initial ¹³⁷Cs activity of samples [Bq]
5.00	58.0 ±0.3	4.25 ±0.03	40.9 ±0.3	66.0 ±0.4	2 137
10.00	52.3 ±0.5	4.80 ±0.06	46.2 ±0.6	72.1 ±0.6	6 475
20.00	45.1 ±0.3	4.64 ±0.02	44.6 ±0.2	70.2 ±0.3	6 543
40.00	35.7 ±3.8	5.31 ±0.51	51.1 ±4.9	77.6 ±5.6	5 830

Proposed recipes for preparation of geopolymer waste forms containing different percentages by weight of fly ash (5%, 10%, 20%, and 40%) artificially contaminated with 137Cs

Geopolymer waste forms with proportion of fly ash [wt.%]	Fly ash [g; d.w.]	Geosil A [g; d.w.]	Geosil B [g; d.w.]	Geosil C [g; d.w.]	Technical water [g]	Final product [g]	NaOH [g; d.w.]
0.00	0.00	42.00	24.00	123.00	111.00	300.00	15
5.00	15.00	38.67	22.10	113.23	111.00	300.00	15
10.00	30.00	35.33	20.19	103.48	111.00	300.00	15
20.00	60.00	28.67	16.38	83.95	111.00	300.00	15
40.00	120.00	15.33	8.76	44.91	111.00	300.00	15

DOI: https://doi.org/10.22630/srees.10058 | Journal eISSN: 2543-7496 | Journal ISSN: 1732-9353

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Language: English

Page range: 55 - 72

Submitted on: Oct 29, 2024

Accepted on: Dec 18, 2024

Published on: Mar 30, 2025

Published by: Warsaw University of Life Sciences - SGGW Press

In partnership with: Paradigm Publishing Services

Keywords:

fly ash,

geopolymers,

solidification/stabilization,

Cs,

leachability,

compressive strength

Related subjects:

Architecture and design,

Architecture,

Architects, buildings,

Geosciences,

Geosciences, other,

Engineering,

Mechanical engineering,

Fundamentals of mechanical engineering,

Geosciences,

Geology and mineralogy

© 2025 Šimon Rezbárik, Lenka Vavrincová, Martin Valica, Vanda Adamcová, Stanislav Sekely, Ján Rezbárik, Miroslav Horník, published by Warsaw University of Life Sciences - SGGW Press
This work is licensed under the Creative Commons Attribution-NonCommercial 4.0 License.

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Solidification/stabilization of fly ash contaminated with radiocaesium into geopolymers

Figures & Tables

FIGURE 1.

FIGURE 2.

Proportion of oxides in fly ash sample originating from Vojany TPP (Slovak Republic)

Physico-chemical and geometric characteristics of prepared geopolymer waste forms

Proposed recipes for preparation of geopolymer waste forms containing different percentages by weight of fly ash (5%, 10%, 20%, and 40%) artificially contaminated with 137Cs

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