Recently, the global attention has focused on sustainable development by promoting a circular economy model. The present PhD project in this context aims to carry out an engineering characterization related to a new application of electric arc furnace slag, as a filler in polymeric matrices, with particular focus on vulcanized rubber. At the same time, a study of these two sectors was carried out, with a view to implementing an industrial symbiosis. The reason why these sectors were chosen is that on the one hand Italy is the main European producer of electric furnace steel, and more than 50% of large Italian companies are located in Lombardy where for this reason a huge quantity of slag is produced. Although the slag is already reused as artificial aggregate, it has been estimated that unfortunately large part is still disposed of in landfills, so it is necessary to study new applications. In this study we focused on elastomeric matrices given the geographical distribution of the companies operating in the particularly dense gasket sector in Lombardy. The issue of waste enhancement is a sensitive issue not only to the steel sector but also to producers of rubber articles as it is not easily reprocessable. The production of rubber articles implies a considerable percentage of intrinsic waste in the process. In this regard, industrial waste from technical articles and also the end-of-life tire powder were recycled through a simple cold calendering process without additives. The influence of slag as a filler was also evaluated in the latter. The work carried out is structured in a first part of literature review and a second part relating to the experimental activity carried out, divided into the different polymeric matrices characterized: I) Comparison of the mechanical behavior of an epoxy resin added with slag and river sand in the so-called epoxy mortars. II) Characterization of a standard NBR added with an increasing percentage of slag. III) Characterization of NBR industrial waste, and influence of the slag in different grain sizes. IV) Analysis of the slag as a substitute and partially substitute filler for carbon black in the NBR matrix. V) Characterization of recycled ELT powder and additives with EAF slag. VI) Analysis of a potential industrial symbiosis between the steel and rubber sectors with the related economic assessment. The results obtained regarding the application of slag as filler in polymeric matrices are encouraging as on the one hand the main problem of the reuse of slag, that is the leaching of heavy metals, can be overcome in this application, and on the other hand it is possible to formulate rubbers, recycled or not, with different quantities and sizes of slag as filler depending on the final application.
Recentemente l’attenzione globale si è focalizzata verso uno sviluppo sostenibile promuovendo un modello di economia circolare. In questo contesto si colloca il presente progetto di dottorato il cui scopo è stato quello di eseguire una caratterizzazione ingegneristica relativa ad una nuova applicazione della scoria da forno elettrico ad arco, come filler in matrici polimeriche, con particolare focus sulla gomma vulcanizzata. Parallelamente è stato eseguito uno studio di questi due settori, nell’ottica di implementare una simbiosi industriale. Il motivo per cui sono stati scelti questi settori è che da una parte l’Italia è il principale produttore europeo di acciaio da forno elettrico, e più del 50% delle grandi imprese italiane di trova in Lombardia dove per questo motivo viene prodotta una ingente quantità di scoria. Nonostante la scoria venga già riutilizzata come aggregato artificiale, è stato stimato che purtroppo ancora buona parte venga smaltito in discarica perciò è necessario studiare nuove applicazioni. Nel presente studio ci si è focalizzati su matrici elastomeriche data la distribuzione geografica delle imprese operanti nel settore delle guarnizioni particolarmente denso in Lombardia. Il tema della valorizzazione dei rifiuti è un tema sensibile non solo al settore siderurgico ma anche ai produttori di articoli in gomma in quanto essa non è facilmente riprocessabile. La produzione di articoli in gomma porta con sé una considerevole percentuale di scarto intrinseca nel processo. A tale proposito, gli scarti industriali da articoli tecnici e anche il polverino di pneumatico fuori uso sono stati riciclati tramite un processo semplice di calandratura a freddo senza l’aggiunta di additivi. L’influenza della scoria come filler è stata valutata anche in questi ultimi. Il lavoro svolto è strutturato in una prima parte di revisione della letteratura e una seconda parte relativa all’attività sperimentale svolta, suddivisa nelle diverse matrici polimeriche caratterizzate: I) Confronto del comportamento meccanico di una resina epossidica additivata con scoria e con sabbia di fiume nelle cosiddette malte epossidiche. II) Caratterizzazione di una NBR standard additivata con una crescente percentuale di scoria. III) Caratterizzazione di sfrido industriale NBR, e influenza della scoria in diverse granulometrie. IV) Analisi della scoria come filler sostituivo e parzialmente sostitutivo del carbon black in matrice NBR. V) Caratterizzazione di polverino PFU riciclato e additivato con scoria EAF. VI) Analisi di una simbiosi industriale potenziale tra il settore dell’acciaio e quello della gomma con relative valutazioni di tipo economico. I risultati ottenuti circa l’applicazione della scoria come filler in matrici polimeriche sono incoraggianti in quanto da una parte la problematica principale del riutilizzo della scoria, ovvero la lisciviazione dei metalli pesanti, può essere superata in questa applicazione, e dall’altra è possibile formulare gomme, riciclate e non, con diverse quantità e dimensioni della scoria come filler in funzione dell’applicazione finale.
TECNOLOGIE E RELAZIONI DI FILIERA PER UN NUOVO ECOSISTEMA INDUSTRIALE: L’APPLICAZIONE DELLA SIMBIOSI INDUSTRIALE NEL SETTORE DEI METALLI TECHNOLOGIES AND SUPPLY CHAIN RELATIONSHIPS FOR A NEW INDUSTRIAL ECOSYSTEM: THE APPLICATION OF THE INDUSTRIAL SYMBIOSIS IN THE METALS SECTOR
GOBETTI, Anna
2022
Abstract
Recently, the global attention has focused on sustainable development by promoting a circular economy model. The present PhD project in this context aims to carry out an engineering characterization related to a new application of electric arc furnace slag, as a filler in polymeric matrices, with particular focus on vulcanized rubber. At the same time, a study of these two sectors was carried out, with a view to implementing an industrial symbiosis. The reason why these sectors were chosen is that on the one hand Italy is the main European producer of electric furnace steel, and more than 50% of large Italian companies are located in Lombardy where for this reason a huge quantity of slag is produced. Although the slag is already reused as artificial aggregate, it has been estimated that unfortunately large part is still disposed of in landfills, so it is necessary to study new applications. In this study we focused on elastomeric matrices given the geographical distribution of the companies operating in the particularly dense gasket sector in Lombardy. The issue of waste enhancement is a sensitive issue not only to the steel sector but also to producers of rubber articles as it is not easily reprocessable. The production of rubber articles implies a considerable percentage of intrinsic waste in the process. In this regard, industrial waste from technical articles and also the end-of-life tire powder were recycled through a simple cold calendering process without additives. The influence of slag as a filler was also evaluated in the latter. The work carried out is structured in a first part of literature review and a second part relating to the experimental activity carried out, divided into the different polymeric matrices characterized: I) Comparison of the mechanical behavior of an epoxy resin added with slag and river sand in the so-called epoxy mortars. II) Characterization of a standard NBR added with an increasing percentage of slag. III) Characterization of NBR industrial waste, and influence of the slag in different grain sizes. IV) Analysis of the slag as a substitute and partially substitute filler for carbon black in the NBR matrix. V) Characterization of recycled ELT powder and additives with EAF slag. VI) Analysis of a potential industrial symbiosis between the steel and rubber sectors with the related economic assessment. The results obtained regarding the application of slag as filler in polymeric matrices are encouraging as on the one hand the main problem of the reuse of slag, that is the leaching of heavy metals, can be overcome in this application, and on the other hand it is possible to formulate rubbers, recycled or not, with different quantities and sizes of slag as filler depending on the final application.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14242/69403
URN:NBN:IT:UNIBS-69403