The objective of this study was to determine the chemical, radiological and leaching properties of slag and ash produced by a thermoelectric unit of a former factory Adriavinil and deposited in the area of Kasktel Gomilica near Split, Croatia. A total of 33 samples were analysed. The bioavailable fraction of the slag and ash was estimated using different leaching tests. The waste material was characterized by a high activity of naturally occurring radionuclides 238U, 235U and 226Ra and by elevated concentrations of heavy metals. The concentrations of most heavy metals were three to four times as high as in the common soil. Uranium slag and ash concentration was almost 40 times higher than in control soil. More than 37% of the total U could be removed from the slag and ash with the sea water.
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Sci Rep
January 2025
College of Hydraulic and Civil Engineering, Xinjiang Agricultural University, Urumqi, 830052, Xinjiang, People's Republic of China.
Aiming at the problem that it is difficult to realize low-cost, high-performance and large-scale utilization of cementitious materials prepared from bulk solid wastes, this paper constructs a set of composite cementitious system based on alkaline activation of slag and fly ash (FA) by calcium carbide slag (CCS) and synergistic activation of sodium sulfate (NaSO) as a chemical dopant. The influence of factors such as solid waste type, mixing ratio, and NaSO content on the mechanical properties of composite cementitious systems was investigated by assessing compressive strength and analyzing microstructure using XRD, SEM-EDS, and FTIR. The test results indicate that CCS and NaSO exert significant influences on the strength of the composite cementitious system.
View Article and Find Full Text PDFEnviron Res
January 2025
Science and Technology Innovation Center of Smart Water and Resource Environment, Northeastern University, Shenyang 110819, China; School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China; Liaoning Institute of Technological Innovation in Solid Waste Utilization, Northeastern University, Shenyang 110819, China.
The preparation of low-carbon cementitious materials through the synergistic coupling of multiple solid wastes has great potential for development, which can improve the problems of resource shortage and environmental pollution. In this paper, a new type of supersulfated cement was developed by using calcium carbide residue (CCR) as an alkaline activator. The effects of CCR content on the mechanical properties and hydration behaviors of the samples under steam curing conditions were discussed.
View Article and Find Full Text PDFEnviron Technol
January 2025
School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan, People's Republic of China.
This study introduces a novel landfill cover material, employing lake sediment as a substrate, stabilised with fly ash, slag, desulfurisation gypsum and construction waste. The mechanical properties, including shear strength parameters, unconfined compressive strength, hydraulic conductivity, volumetric shrinkage, and water content, of the solidified sludge were evaluated. The microscopic mechanism of the solidified sludge were investigated through XRD, FTIR, and SEM-EDS techniques.
View Article and Find Full Text PDFJ Environ Manage
January 2025
School of Business, Xi'an University of Finance and Economics, Xi'an, 710100, China.
The purpose of this study is to solve the problem of ammonia (NH) release when modified magnesium slag (MMS) is used as coal mine backfill cementitious material, and to explore its chemical mechanism and put forward effective solutions. Uniaxial compressive strengths (UCS) hydration kinetics, scanning electron microscope (SEM), and thermogravimetric analysis-derivative thermogravimetry (TG-DTG), X-ray diffractometer (XRD) and other testing methods were used to study the evolution of the properties of MMS-based backfill material, which provided a scientific basis for the safe utilization of MMS. First, the chemical mechanism underlying the release of NH from MMS was identified, and it was confirmed that MgN and LiN are the main nitrogen sources.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
School of Civil Engineering and Transportation, Northeast Forestry University, Harbin 150040, China.
This article systematically investigated the improvement effect of polypropylene fiber (PPF) on the mechanical and freeze-thaw properties of alkali-activated fly ash slag concrete (AAFSC) with high fly ash content and cured at room temperature. Fly ash and slag were used as precursors, with fly ash accounting for 80% of the total mass. A mixed solution of sodium hydroxide and sodium silicate was used as alkali activator, and short-cut PPF was added to improve the performance of AAFSC.
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