1,721,048 research outputs found
Il possibile utilizzo delle ceneri volanti e pesanti
No full textDalla combustione del carbone e di altri combustibili, del legno, di residui agricoli e di rifiuti
solidi urbani si può ottenere una gran quantità di ceneri.
Dall’incenerimento di una tonnellata di rifiuti urbani si ottengono circa 30 kg di ceneri volanti
e 300 Kg di ceneri pesanti.
Le ceneri volanti rappresentano la frazione fine, leggera o termolabile dei residui derivanti
dalla combustione dei rifiuti e/o possono costituire la frazione principale della combustione
del carbone che viene trascinata dai fumi via via più freddi, ricondensando sotto forma di
piccole particelle sferoidali.
Il residuo solido della combustione è rappresentato dalle ceneri pesanti; quelle provenienti
dalla combustione del carbone, chiamate così perché fondendo cadono direttamente sul fondo
della caldaia, ammontano al 10-15% dell’inerte di partenza.
Le ceneri volanti e pesanti, contaminate da preoccupanti inquinanti ambientali in quantità e
qualità a seconda della combustione da cui provengono e/o del rifiuto incenerito, se stoccate
in discarica, possono essere responsabili dell’inquinamento ambientale e pertanto nocive per
la salute umana.
Un modo per risolvere il problema è quello di convertirle in nuovi prodotti.
Questo lavoro si prefigge di fare un’ampia panoramica sulla provenienza delle ceneri volanti e
pesanti, sulla loro composizione e di conseguenza sull’uso che se ne può fare
La vetrificazione delle ceneri e il processo WBRM
No full textFly and bottom ashes, produced by incineration plants and/or as by-products of coal
combustion in thermal power plants, include, even if in different amounts, heavy metals,
dioxins and furans, as well as a considerable amount of SiO 2, that is the main component of
glass: therefore these wastes can be utilized as raw materials for the production of composite
materials.
Vitrification is a method that: i) allows to immobilize the dangerous materials if present in the
ashes; ii) produces materials that are inert towards a lot of chemical compounds and iii)
allows to notably reduce waste volumes.
The WBRM process, one of the most studied vitrification projects in the last years, substained
by the European Union, foresees glass fiber production by utilizing fly ashes coming from
municipal solid wastes and other special waste combustion, properly mixed with specific
different correctors according to their possible subsequent applications. The fibers obtained
show physical and mechanical characteristics analogue to the glass fibers of the type E, at
present used in the production of clothes, textiles, plastic materials and bituminous coverings,
and are more resistent to the attack of alkaline compounds in respect of the glass fibers of the
type E.
The WBRM process, by using and thermically treating fly ashes, gives full value to these
types of wastes, representing a useful alternative to landfills
Atti del XXV Congresso Nazionale di Scienze Merceologiche. "Il contributo delle Scienze Merceologiche per un mondo sostenibile"
No full textDeterminazione gascromatografica degli acidi grassi liberi nelle acque di vegetazione degli oleifici
No full textE’ stato sviluppato un metodo per la determinazione gascromatografica (GC) degli acidi grassi
liberi nelle acque di vegetazione degli oleifici (AV). Il campione in esame è stato acidificato a pH
2-3 per far precipitare le proteine. La frazione colloidale è stata eliminata per aggiunta di acetone e
le interferenze dovute ai composti fenolici per aggiunta di polinivinilpirrolidone. Il campione è stato
chiarificato per centrifugazione e un’aliquota è stata successivamente iniettata nel sistema GC. Sia
gli acidi grassi a catena C2-C8, derivanti dal metabolismo microbiologico, che gli acidi grassi a
catena C16-C18, provenienti dall’olio originariamente presente nelle olive, sono stati quantificati in
una sola analisi utilizzando l’acido nonanoico come standard interno. In generale sono state trovate
quantità piuttosto elevate di acido acetico, nell’intervallo da 1.000 a 4.000 mg/L di AV.
Abstract.
A method was developed for the gas chromatographic (GC) determination of free fatty acids (FFA)
in olive mill waste waters (OMW). The sample under examination was acidified to pH 2-3 to cause
protein precipitation. Elimination of the colloidal fraction was obtained by addition of acetone.
Polyvynilpirrolidone was added to eliminate the interference by phenolic compounds. The sample
was then clarified by centrifugation and an aliquot was injected into the GC system. Both the C2-C8
FFA, coming from microbial metabolism, and the C16-C18 FFA, coming from the oil originally
present in the olives, were quantified in a single run by employing nonanoic acid as the internal
standard. Rather high amounts in particular of acetic acid were generally found, usually in the range
from 1,000 to 4,000 mg/L of OMW
From Regulatory Requirements to Voluntary Certifications in the Agricultural and Food Industry: the Case of Da Re
No full textSafety, quality of products and attention for nutritional needs, requested by a healthy diet, are substantial features and at the same time aspects of great interest for companies working in the agricultural and food industry. This paper presents the case of the Da Re company, that makes bakery products for national and international markets. Beyond the application of the HACCP system, required by law, Da Re obtained also some voluntary certifications: ISO 9001:2000 (since 2002 to 2008), IFS (since 2009) and BRC (since 2012). The last ones, in particular, are functional to the strategic choice to launch a development plan in the UK and American markets. Da Re, by employing suitable indicators, is able to accurately monitor compliance of internal processes, suppliers' reliability and quality perceived by markets
Monitoraggio di metalli pesanti nelle emissioni al camino in un'industria cementiera che utilizza combustibili non convenzionali
No full textThe complexation reactions of N-methylated polyamines with silver(I) in dimethylsulfoxide
No full textRecovery of Secondary Raw Materials by Trevimetal for a Circular Economy in the Perspective of Sustainable Development
No full textThe transition from a linear to a circular economy is essential for a sustainable development. Advantages can be obtained in particular by a useful exploitation of virgin materials which are necessary for human activities. Circular economy has to rely on renewable energies and a proper waste management. Separate waste collection, recycling and re-use of materials provide evident benefits, even if the economical ones gradually become more and more difficult to be achieved. The waste collection sector is related to a better exploitation of secondary raw materials, for which an innovative legislation could realize a passport of the materials which are able to guarantee the traceability and the information about their composition for assessing the possibility of their re-using and recycling at the end of the life cycle.
Trevimetal is a company located in the province of Treviso (Italy) and is specialized in the collection, transport, selection, working and final re-cycling of metals and scrap iron. By a modern plant, the society is able to recover the 100% of the scrap iron. In 2015 metal scrap devoted to steel industries and foundries was 70.3 % of the whole waste treated. Trevimetal employs a radiometric gateway to detect the radioactivity of the metals and scrap iron in income and outcome, and a phytodepuration plant for the treatment of waste waters, in order to achieve the goal of sustainable development.
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