1. Zeolitization characteristics of fly ashes from wet- and dry- disposal systemsBhagwanjee Jha, D. N. Singh, 2012, izvirni znanstveni članek Opis: The fly ash disposal at thermal power plants is either through wet- or dry-disposal systems. As these disposal practices result in different characteristics for the fly ashes, their interaction with alkalis, and hence the zeolitization potential, will be different. In order to demonstrate this, investigations were conducted to study the physical, chemical, mineralogical and morphological characteristics of the residues of the fly ashes collected from the lagoons and hoppers of the same thermal power plant, after their hydrothermal treatment. Field-emission-gun scanning electron microscopy and X-ray diffraction analysis of these residues demonstrated that the hopper ash attains an exceptionally high cation-exchange capacity and $SiO_2/Al_2O_3$ ratios (SAR), which correspond to the formation of major fly ash zeolites as compared to its counterpart. In other words, the study presented here helps to establish the superiority of hopper ash over lagoon ash for synthesizing fly ash zeolites and their enhanced quantity and quality.
Ključne besede: alkali activation, lagoon ash, hopper ash, fly ash zeolites
Objavljeno v DKUM: 13.06.2018; Ogledov: 879; Prenosov: 89
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2. Modification of polyamide knitted fabric using different zeolitesAlenka Ojstršek, Tomaž Fakin, Karin Stana-Kleinschek, Darinka Fakin, 2017, izvirni znanstveni članek Opis: The aim of this research was to apply three different types of zeolites and the combination thereof in the form of a very fine powder, together with different chemicals and additives on polyamide knitted fabric according to an industrially acceptable exhaustion procedure in order to study changes in the morphology, optical properties and wettability of surfaces. Zeolites were analysed using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and gas physiosorption. Additionally, the morphology of zeolite-coated surfaces was examined closely using SEM, while changes in molecular-chemical level were examined by means of IR spectroscopy. Optical properties were studied using CIE colour measurement and diff use reflectance profi le determination, while the hydrophilic/hydrophobic character was examined using goniometry. The obtained results show the suitability of the employed exhaustion procedure, depending on the type of zeolite and the composition of the treatment bath. The results also provided evidence of the enhanced wettability of PA fabrics using 4A and 13X zeolites in combination with selected additives.
Ključne besede: zeolites, polyamide fibres, exhaustion, surface modification, wettability
Objavljeno v DKUM: 31.08.2017; Ogledov: 1095; Prenosov: 397
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3. Multiple-effect evaporation in aluminosilicate technologyDušan Klinar, Janvit Golob, 2001, strokovni članek Opis: The article presents an engineering approach to the development of an alternative production with the existing equipment. Zeolite production is becoming an alternative to the old »Bayer« process for aluminum hydrate production. By applying appropriate know-how old equipment was used for an economically as well as ecologically acceptable production. In this equipment adaptation among other production steps the multistage evaporation battery was the most critical part of the process. We applied semi empirical approach on the basis of Z. Rant ideas to find heat transfer coefficients and to determine which equipment elements are more relevant for efficient performance and need serious maintenance.
Ključne besede: chemical engineering, evaporation in silicate technology, bauxite alumina production, evaporators, process optimization, heat transfer, heat flow, empirical equations, heat transfer coefficients, zeolites
Objavljeno v DKUM: 24.08.2017; Ogledov: 1208; Prenosov: 96
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