Comparison of geopolymer and cement as solidification matrixes for radwaste oil treated with bentonite
DOI:
https://doi.org/10.15392/bjrs.v9i1A.1455Keywords:
radwaste oil, cement, geopolymerAbstract
Lubricating oils in nuclear power plants may contaminate with radionuclides and become a challenging radwaste for treatment because they decompose in storage and disposal. In addition, conventional methods of immobilization in cement should be checked. This work intends to compare cement and geopolymer used to solidify lubricating oil previously decontaminate using bentonite as sorbent material. Cement is a well-known matrix for radwaste immobilization and geopolymer (alkali-activated material) has been proposed as a new immobilization technology, due to its advantages comparing to cement and bitumen. The geopolymers are cementitious binders formed by aluminosilicates activated in alkaline medium. Synthesis occurs by means of polymerization or polycondensation reactions from the dissolution of SiO44- and AlO45- ions of the aluminosilicates in a highly alkaline solution. After the treatment of the oil radwaste, the contaminated bentonite was immobilized in geopolymer and cement matrix and the final immobilized waste properties were evaluated: compressive strength and homogeneity. The compressive strength result in cement matrix specimens (13,38 MPa) has been higher than in geopolymer matrix (5,96 MPa). Nevertheless, when the homogeneity was compared, the resultant waste in geopolymer presented an aspect more homogeneous than the in the cement matrix. The results showed that the contaminated bentonite was not distributed homogeneously in cement matrix, for this reason the cement was not adequate to solidify the simulated waste. The compressive strength result for the waste in geopolymer matrix did not meet the Brazilian waste acceptance criteria. Therefore, new compositions of geopolymer matrix using less water will be carried out to improve the compressive strength and reach the recommended by Brazilian legislations.
Downloads
References
BELANGER, R.L. "Method of removing radioactive waste from oil." Patent Number: 4615794. 1986.
CUCCIA, V.; SELES, S.R.N.; LADEIRA, A.C.Q. "Removal of cobalt from lubrificanting oil by the use of bentonite: equilibrium, kinetic and adsorption preliminary studies." Brazilian J. Radiat. Sci, v. 7, 2019.
EL-NAGGAR, M.R.; AMIN, M.; "Impact of alkali cations on properties of metakaolin and metakaolin/slag geopolymers:" Microstructures in relation to sorptionof134Cs radionuclide. J of Hazar Mat, v. 344, p. 913–924, 2018.
ANTUNES BOCA SANTA, R. A., SOARES, C., & RIELLA, H. G. Geopolymers obtained from bottom ash as source of aluminosilicate cured at room temperature. Construction and Building Materials, v. 157, p. 459–466, 2017.
DAVIDOVITS, J. 30 years of successes and failures in geopolymer applications: market trends and potential breakthroughs. In: GEOPOLYMER CONFERENCE 2002, October 28e29, Melbourne, Australia, 2002.
IAEA. "The Behaviors of Cementitious Materials in Long Term Storage and Disposal of Radioactive Waste." IAEA-TECDOC-1701. IAEA-TECDOC-1701 2013.
DRECHSLER, M.; GRAHAM, A. Geopolymers, "An Innovative Materials Technology Bringing Resource Sustainability to Construction and Mining Industries. 48TH INST. QUARR. CONF. 12, 2005.Available at: <https://doi.org/10.13140/2.1.4108.8006>Last accessed: 15April 2019.
OLAWALE, M.D., "Syntheses, Characterization and Binding Strength of Geopolymers: A Review." Int. J. Mater. Sci. Appl. v. 2, p.185, 2013.
ABDOLLAHNEJAD, Z., HLAVACEK, P., MIRALDO, S., PACHECO-TORGAL, F., AGUIAR, J.L.B. Compressive strength, microstructure and hydration products of hybrid alkaline cements. Mater. Res. v. 17, p. 829–837, 2014.
ABNT. NBR 5739. Concreto - Ensaio de compressão de corpos-de-prova cilíndricos, Associação Brasileira de Normas Técnicas, 2007.
AUGHENBAUGH, K.L.; WILLIAMSON, T.; JUENGER, M.C.G. "Critical evaluation of strength prediction methods for alkali-activated fly ash. Mater. Struct. v. 48, p. 607–620, 2015.
KOMMITSAS, K.; ZAHARAKI, D. Minerals Engineering. v 20, p. 1261, 2007.
CNEN "Critérios de aceitação para deposição de rejeitos radioativos de baixo e médio níveis de radiação." CNEN-NN-6.09 - Resolução CNEN 012/02, 2002.
Downloads
Published
Issue
Section
License
Copyright (c) 2021 Brazilian Journal of Radiation Sciences
This work is licensed under a Creative Commons Attribution 4.0 International License.
Licensing: The BJRS articles are licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
How to Cite
