In this work, we firstly examined the technical feasibility of geopolymer synthesis from the coal fly ash with high iron oxide (48.84 wt.%) and calcium oxide (22.15 wt.%) contents. The heat resistance of geopolymer was represented by the dry weight loss which ranged from 2.5 to 4.9% and was better than that (11.7%) of OPC. However, the high iron oxide content made the acid resistance (13-14%) of geopolymer inferior to OPC. The economics of geopolymer production changes significantly upon the variation in the arrangement of material use and geopolymer price. The costs of NaSiO and NaOH and the benefit of geopolymer selling were the major factors affecting the economic feasibility of geopolymer production. When the NaSiO price was around 400 USD/ton, the geopolymer production will be profitable even if the geopolymer price was as low as 50 USD/ton. It is possible to improve the economics of geopolymer production by varying the arrangement of material use while not impairing the performance of geopolymer.
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http://dx.doi.org/10.1016/j.jhazmat.2018.08.089 | DOI Listing |
J Chem Phys
January 2025
Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Centre Telč, 58856 Telč, Czech Republic.
The time-evolution of dynamics as well as microstructure and mechanical response of phosphate-based geopolymers was probed using x-ray photon correlation spectroscopy and rheological tests. The analyzed relaxation processes in the freshly prepared geopolymer mixes evidenced a q-independent mode of the autocorrelation function, ascribed to density fluctuations of the already established molecular network, undergoing reconfiguration without significant mass transport. Upon curing, the detected motions are localized and depict a system evolving toward structural arrest dominated by slower hyperdiffusive dynamics, characterized by a compressed exponential regime, pointing to a structural relaxation process subjected to internal stresses, in a context of marked dynamical and structural heterogeneity.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Faculty of Materials Engineering and Physics, Cracow University of Technology, Jana Pawła II 37, 31-864 Cracow, Poland.
Geopolymer materials are increasingly being considered as an alternative to environmentally damaging concrete based on Portland cement. The presented work analyzed waste from mines and waste incineration plants as potential precursors for producing geopolymer materials that could be used to make lightweight foamed geopolymers for insulation applications. The chemical and phase composition, radioactivity properties, and leachability of selected precursors were analyzed.
View Article and Find Full Text PDFJ Environ Manage
January 2025
China MCC22 Group Corporation Ltd., No.16 Xingfu Road, Fengrun District, Tangshan, Hebei, China.
Bayer red mud is a highly alkaline industrial solid waste generated during alumina production, and its massive discharge and stockpiling poses significant environmental risks. The strong alkalinity of red mud is a primary challenge limiting its effective utilization. This study systematically analyzes the composition and characteristics of alkaline components in red mud, emphasizing the roles of soluble free alkali and chemically bound alkali in regulating its alkalinity.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
Department of Civil Engineering, SRM University-AP, Andhra Pradesh, Amaravati, India.
Environ Res
December 2024
Department of Physics, King Fahd University of Petroleum & Minerals, Saudi Arabia; KACARE Energy Research & Innovation Center, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
In light of the growing need to mitigate climate change impacts, this study presents an innovative methodology combining ensemble machine learning with experimental data to accurately predict the carbon dioxide footprint (CO-FP) of fly ash geopolymer concrete. The approach employs adaptive boosting to enhance decision tree regression (DTR) and support vector regression (SVR), resulting in a robust predictive framework. The models used key material features, including fly ash concentration, fine and coarse aggregates, superplasticizer, curing temperature, and alkali activator levels.
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