1,721,118 research outputs found
End of life-materials: WEEE glass recovery in construction sector
No full textIn this work was investigated the feasibility to use Waste Electrical and Electronic Equipment (WEEE) glasses in construction sector as secondary raw material. WEEE glasses were used in different percentages as a function of the product obtained: 30-40wt% for glaze formulations, about 40wt% for glass-ceramics and 5wt% in brick bodies. The laboratory and industrial scale up results demonstrated that it is possible to produce a glazed tile with a glaze containing fluorescent lamps glass instead of commercial ceramic frits. Glass-ceramics composed by nepheline ((Na,K) AlSiO 4), akermanite (Ca 2Mg(Si 2O 7)) and celsian (BaAl 2Si 2O 8) were obtained at low temperature and short time (T = 900°C and t = 60 min) with panel glass as component. Besides, small amounts of panel glass were added in brick bodies because this glass is suitable as fluxing agent only at high temperatures; at brick manufacturing temperatures (around 1000°C), the glass viscosity does not enough contribute to the sintering process
Binary and ternary mixtures of deflocculant additives for whiteware slurries
No full textIn the traditional ceramic field, during the wet grinding stage liquid mixtures of additives are commonly used to guarantee high solids content (65-72 wt%) and a viscosity low enough to allow the suspension's workability. These characteristics are indispensable for using the new technologies for wet grinding (cylindrical and conical continuous mills) that require only 3-4 h of milling and permit considerable productivity (20 t/h). This work reports a laboratory study on the rheological behavior of whiteware slurries added with binary and ternary deflocculant mixtures
Recovery of glazing ceramic sludge in construction materials
No full textCeramic glazing sludge deriving from the purification process of waste-water obtained by the glazing tile phase was mixed in equal proportion with glass cullet in order to obtain a high sintered product suitable to be used as floor/wall covering tiles. The characterization of fired samples includes the evaluation of both sintering parameters: water absorption, linear shrinkage and apparent density according to the ISO rules and sintering temperatures estimated by optical heating microscope. Satisfactory results were achieved from technological tests and SEM analysis showed a dense microstructure with crystalline phases similar to commercial glass-ceramic, identified by X ray diffraction. Besides, the obtainment of these products was achieved with energy saving due to the lower firing temperatures (about 1000°C) with respect to commercial products for floor/wall covering (about 1200°C)
Sintered glass-ceramics from end of life cathode ray tubes glass
No full textThe recycling of end of life cathode Ray Tubes from TV sets and PC monitors is still an unsolved problem. This study presents the feasibility results of the panel glass recycling glass from end of life TV sets as secondary raw material in glass-ceramic productions. The sintering and crystallization processes of the glass-ceramics resulting from the mixing of 50wt% glass with different percentages of dolomite and alumina was studied. The crystallization and densification processes were examined by DTA, XRD and SEM techniques and by linear shrinkage, density and water-absorption studies. The influences of heat treatment temperature was analysed. The best glass-ceramics consolidation and densification was obtained at 900°C for the lower rate alumina composition. The crystallisation begins near 900°C in grain surfaces and expands in the bulk with increasing temperature (1000°C). These glass-ceramics are composed of nepheline, akermanite and celsian, crystalline phases present also in commercial glass-ceramics such as Pyroceram and responsible of high mechanical strength
Sintered glass-ceramics and glass-ceramic matrix composites from CRT panel glass
No full textSintering with simultaneous crystallization of powdered glass represents an interesting processing route for glass-ceramics, especially originating from wastes. Highly dense glass-ceramic samples may be obtained from a simple and short treatment at a relatively low temperature. In addition, glass ceramic matrix composites may be obtained by mixing glass with suitable reinforcements. In this work sintered nepheline glass-ceramics, based on panel glass from cathode ray tubes (CRTs), are illustrated. A limited addition of Al2O3 platelets caused a significant improvement in the mechanical properties (elastic modulus, bending strength, microhardness, fracture toughness), already remarkable for the un-reinforced glass-ceramic, compared to traditional nepheline glass-ceramics
Synthesis and characterization of biochar-based geopolymer materials
Full text linkThe aim of this research is to evaluate the possibility to realize alkali-activated materials exploiting biochar, a secondary raw material coming from pyrolysis/gasification processes, for environmental benefits, such as improvement of soil fertility and reduction of CO2 emissions into the atmosphere thanks to the carbon sink process where carbon dioxide is subtracted from the cycle of carbon. For the matrix of the geopolymers, a waste material derived from incinerator bottom ash was used and compared to pure metakaolin matrix. The materials obtained are lightweight and porous, with high water absorption capacity and moisture adsorption/desorption. BET analysis shows an increase in specific surface by increasing the biochar content and the biochar acts as a filler in the pores. From porosimetry analysis it is possible to follow the evolution of the curing process of the geopolymer prepared: specimens containing 70 wt% biochar after 28 and 90 days showed an increase in total Hg intrusion volume, pore area and total porosity but a decrease in the dimensions of pores. Due to the technical properties of materials containing biochar, they can be used in the future for a cleaner design of products in the field of sustainable construction for insulating panels or lightweight materials for houses and gardens in terraces and balconies
Esempi di utilizzo in impasti di gres porcellanato delle argille plastiche SC1, SC2 e SC3 prodotte dalla Sarda Silicati
No full textEditorial: The Role of Microbiota in the Onset and Development of Intestine and Liver Diseases and Cancer: Molecular and Cell Mechanisms
Full text linkInorganic wastes as new resource of materials
No full textRecycling and valorisation of waste materials coming from municipal and industrial processes has become an urgent problem. Moreover, national regulations are reinforcing environmental protection measures, thus rendering the development of new recycling technologies necessary and convenient. By considering that both the ceramic industry is a high consumer of natural raw materials and these materials develop crystalline phases and glassy matrices capable to block the wastes it is easy to understand that the ceramic sector represents an important reference point for the recycling of wastes. The experimental work has been carried out by mixing incinerator bottom ash and steel ash in both a ceramic paste for red single firing and in a body for facing bricks. The samples characterisation has been conducted by means of linear shrinkage, water absorption, density, porosity, crystalline phases identification, plasticity, loss in weight and surface defects. From this feasibility study, can be evinced that both the processes allow the introduction of wastes in terms of chemical, physical, mineralogical and esthetical compatibility, in particular for percentage up to 5wt% because higher percentage causes major modifications in the standard bodies
Effects of Fullerenes and Single-Wall-Carbon-Nanotubes on murine and human macrophage cells
No full textThe discovery in 1985 of C-fullerenes, a novel carbon allotrope with a polygonal structure made up solely by 60 carbon atoms, and in 1991 of C-nanotubes, thin carbon filaments (1–3 ?m in length and 0.001 ?m in diameter) with extraordinary mechanical properties, opened a wide field of activity in carbon research. While toxicity and biocompatibility of C-fullerenes have been widely investigated, literature data concerning the biological properties and biotoxicity of C-nanotubes are poor and contradictory. Here we test the ability of highly purified C-Single-Walled-Nanotubes (SWNTs) and C-fullerenes to elicit an inflammatory response by murine and human macrophage cells in vitro. In order to determine the potential of these C-derivatives as biological inducers of inflammatory reactions we evaluate the ability of C-single-walled nanotubes and C-fullerenes to induce the release of NO by murine macrophages cells, to stimulate the phagocytic activity of human macrophage cells and to be cytotoxic against these cells. We show that SWNTs-C-nanotubes, when highly purified, as well as C-fullerenes, do not stimulate the release of NO by murine macrophage cells in culture, their uptake by human macrophage cells is very low, and they possess a very low toxicity against human macrophage cells
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