Alkali activation of different type of ash as a production of combustion process

Nenadović, T.; Ferone, Claudio; Kljajevic, M Ljiljana; Mirković, Miljana; Todorović, Bratislav Ž.; Vukanac, Ivana; Nenadović, Snežana

doi:10.2298/ntrp201120006n

Cited by 3 publications

(2 citation statements)

References 22 publications

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“…This coated effect of PVA might delay the geopolymerization rate and reduce the compressive strength of GP2 relative to GP1. Presented radioactivity results confirm previous research [ 65 , 66 , 67 ] that after geopolymerization reaction of the raw materials and clays, lower values of gamma emitter activity are detected in the final products of fly ashes. The importance of I γ , H ex , H in indexes is about 50% lower in geopolymer samples, especially in GP2 than in FA01.…”

Section: Discussionsupporting

confidence: 89%

Potential Usage of Hybrid Polymers Binders Based on Fly Ash with the Addition of PVA with Satisfying Mechanical and Radiological Properties

Mirković

Kljajević

Dolenec

et al. 2021

Gels

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Since recycled technologies usage is mandatory for environmental safety, and in this regard, it is important to examine new materials that can be used in construction and are primarily produced from fly ash. In addition to characteristics such as hardness and compressive strength, the given materials must also be radiologically and environmentally safe. The main concept of engineered geopolymer gel composites based on fly ash residues is focused on developing binder materials via gel formation processes that can replace ordinary cement materials. This study is unique in researching the potential use of fly ash from the Nikola Tesla thermal power plant in Serbia, where the hybrid geopolymeric materials synthesized from fly ash are experimentally examined with the addition 1 wt% and 2 wt% of polyvinyl alcohol (PVA). This paper aims to investigate the structural, morphological, mechanical, and radiological properties of hybrid materials with the addition of PVA and without additive in the period of ageing for 28 days at room temperature. The phase composition was investigated using X-ray powder diffraction (XRPD) analysis, while morphological characteristics of these materials were examined using scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDS). Vibrational spectra of obtained samples are investigated using diffuse reflectance infrared Fourier transform (DRIFT) and Fourier transform infrared (FTIR) techniques. The hardness and compressive strength are also examined, indicating that the 1 wt% addition in geopolymeric matrix results in the best mechanical properties. Radiological measurements of investigated all geopolymer samples show decreasing activity concentrations of radionuclides for 50% compared to fly ash.

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Section: Discussionsupporting

confidence: 89%

Potential Usage of Hybrid Polymers Binders Based on Fly Ash with the Addition of PVA with Satisfying Mechanical and Radiological Properties

Mirković

Kljajević

Dolenec

et al. 2021

Gels

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“…Figure 1 shows the DRIFT spectra for geopolymer samples doped with 1.0 and 5.0 wt.% of two rare earth oxides Sm 2 O 3 and Nd 2 O 3 , denoted as GPE1 and GPE5 (E is Nd or Sm), respectively. The DRIFT spectrum for GPNd1 and GPNd5 ( Figure 2 a) exhibits a high intensity band at 1090 cm −1 that is assigned to asymmetric stretching of Si-O-T bonds [ 28 , 32 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ] (where T = Al or Si in tetrahedral coordination) and a low-intensity band at 810 cm −1 that is assigned to symmetric stretching of Si-O-T bonds [ 41 ]. The bands at ~460 cm −1 can be related to the Si-O-Si bending mode, and reflectance at 560 cm −1 can be attributed to the Si-O-Al vibrations.…”

Section: Resultsmentioning

confidence: 99%

Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Nenadović

Kljajević

Ivanović

et al. 2021

Gels

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The present work was focused on doping of 1% and 5% both of Nd2O3 and Sm2O3 in geopolymer gels. One of the main goals was to determine the influence of the behavior of Nd and Sm as dopants and structural nanoparticles changes of the final geopolymer formed. It is shown that the disorder formed by alkali activation of metakaolin can accommodate the rare earth cations Nd3+ and Sm3+ into their aluminosilicate framework structure. The main geopolymerization product identified in gels is Al-rich (Na)-AS-H gel comprising Al and Si in tetrahedral coordination. Na+ ions were balancing the negative charge resulting from Al3+ in tetrahedral coordination. The changes in the structures of the final product (geopolymer/Nd2O3; Sm2O3), has been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis with energy dispersive spectrometry (EDS). Nucleation at the seed surfaces leads to the formation of phase-separated gels from rare earth phase early in the reaction process. It is confirmed that Nd and Sm have been shown to form unstable hydroxides Nd(OH)3 and Sm(OH)3 that are in equilibrium with the corresponding oxides.

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Environmental protection in natural gas industry comparison of different spatio-temporal radiological risk assessment scenarios

Getaldic,

Suric-Mihic,

Veinovic

et al. 2023

NUCL TECH RAD PROT

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The paper analyses results of spatio-temporal radiological risk assessment scenarios based on existing in-situ long-term monitoring data from a natural gas processing plant to analyse the effect of different input data on the assessment outcome. The ERICA Assessment Tool was used to estimate the dose rates to biota and potential impacts due to the exposure to ionising radiation. The input data for radiological risk assessment scenarios included annual data on activity concentration of radionuclides in soil from measurements performed from 1994 to 2016 and laboratory gamma-spectrometric data related to the period from 2014 to 2019. Predicted total dose rate to biota was generally below the ERICA Tool's screening dose rate of 10 ?Gyh-1 or slightly above, with the highest total dose rate estimated for lichen and bryophytes. Total dose rates to lichen and bryophytes in the studied period show certain temporal variation, but a specific trend was not detected. Estimated total dose rates to biota from different assessment scenarios were below internationally proposed reference levels for which no detrimental effects are expected. The overall potential radiological risk to terrestrial biota from the operation of the natural gas processing plant was found to be negligible.

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Alkali activation of different type of ash as a production of combustion process

Cited by 3 publications

References 22 publications

Potential Usage of Hybrid Polymers Binders Based on Fly Ash with the Addition of PVA with Satisfying Mechanical and Radiological Properties

Potential Usage of Hybrid Polymers Binders Based on Fly Ash with the Addition of PVA with Satisfying Mechanical and Radiological Properties

Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Environmental protection in natural gas industry comparison of different spatio-temporal radiological risk assessment scenarios

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