Στόχος της παρούσας διπλωματικής εργασίας είναι, αφότου γίνει ανάλυση όλων των παραμέτρων της παραγωγικής διαδικασίας, να τεθούν οι «Βέλτιστες Διαθέσιμες Τεχνικές» (ΒΔΤ) της χρήσης των αποβλήτων στην κεραμική βιομηχανία.
Ωστόσο, το μεγάλο πρόβλημα που αντιμετωπίζει η κεραμική βιομηχανία στις μέρες μας, είναι ότι αδυνατεί να χρησιμοποιήσει απόβλητα (επικίνδυνα ή μη), πράγμα που δεν ισχύει στην περίπτωση της βιομηχανίας τσιμέντου, όπου η χρήση αυτών των αποβλήτων είναι πιστοποιημένη. Η ύπαρξη ΒΔΤ για την χρήση αποβλήτων στη παραγωγή τσιμέντου θα αποτελέσει την βάση για την επικαιροποίηση και αντίστοιχων ΒΔΤ και στην κεραμική βιομηχανία.
Μέχρι να φτάσει το στάδιο της επικαιροποίησης, είναι απαραίτητο να γίνει πρωτίστως αναφορά στα απόβλητα και να διευκρινιστεί ποια από αυτά δύνανται να χρησιμοποιηθούν ως πρώτη ύλη. Προκειμένου να φτάσει κανείς σε αυτό το αποτέλεσμα, θα γίνει ανάλυση των χαρακτηριστικών των αποβλήτων και του τρόπου με τον οποίο μπορούν να ενσωματωθούν στην πρώτη ύλη του κεραμικού.
Η επιτυχής επικαιροποίηση των ΒΔΤ της κεραμικής και ειδικά πάνω στην χρήση των αποβλήτων, είναι ένας πάρα πολύ σημαντικός στόχος, καθώς θα δώσει ώθηση σε έναν κλάδο της βιομηχανίας να παράγει προϊόντα που βρίσκουν καθημερινή εφαρμογή. Επίσης, σημαντικό είναι το γεγονός της απαλλαγής των ρίπων και του προβλήματος αποθήκευσης ή διάθεσης τους, με αρνητικά αποτελέσματα για το περιβάλλον.
This thesis is going to refer to the “Best Available Technics” (BAT) of the Ceramic Industry. The BATs are an appropriate guide for an industry on how to operate. They inform, how to proceed in the production of a product from raw material to its final form. More specifically, will be mentioned the BATs which referred to the use of wastes.
In the first chapters, is discussed the orientation of the European Union for the termination of the existence of wastes. For this reason, it is searching different choices of how to manage the big loads of wastes, which are produced by industries. Especially, the metallurgical industry and the power plants are one of the biggest providers of waste. In most occasions, these wastes are toxic, including in their structure heavy metals which are very dangerous for the environment and the human life as well.
Thus, a way to confront the problem is to find a way of recycling. With recycling, the waste of an industry is the raw materials feeding another industry. Until today, this happens only in the cement industry, where a lot of different wastes are used either as raw materials or as fuel. The use of wastes in the cement industry is acceptable and the BATs have already established years before and the experience in their use is valuable. So, the BATs of cement industry can be the base for the BATs of the ceramic industry. The reason is this: In these two industries, similar technics are used in the production, such as firing temperatures, but also similar raw materials can be used.
There are the two main reasons we are willing to use wastes as raw materials. The first one is that we can save natural raw materials, such as clay, because the wastes can replace a part of the amount of raw material is needed. The important thing in this occasion is that the waste must be compatible with the natural raw materials, so that the final product must not have inferior quality. The second reason is the protection of the environment. If the wastes are used as raw material, is not needed to find a way to store them in landfills, having the fear of an accident, such as a leach to the soil and the aquifer.
One of the mostly used waste in the cement industry is the fly ash from the power plants, which is used to produce the Portland cement. Other types of waste are the
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blast furnace slag, steel slag which are coming from the metallurgical industry. Also, waste with organic origin can be used such as the sewage sludge, the alternative solid fuel, the olive stone wooden residue and other ones.
In the following chapters of the current thesis, is also analyzed the use of each one waste which is used from the cement industry and the same time EU has already approved its use. Analyzing all the characteristics of the waste and the reason why it is chosen. Characteristics such as high concentration in Fe, Si, Ca and Al, is a positive criterion to choose this waste.
There has been made a thorough analysis for the ceramic industry. Analyzed the nature and how raw materials are processed, from the extraction of a quarry to the final product, such as bricks, roof tiles and many other ceramic products. The chemical composition of clays used, is very similar to the wastes used also in the cement industry. Thus, we have the knowledge to use them properly and in the ceramic industry.
To approve the use in ceramics it is necessary to examine the compatibility of wastes as raw materials. There are lots of examples studying the use of different types of wastes in the literature, most of them conclude that conglomeration in the clay body is possible. In conglomeration the important factor that should be taken into account, is that the final product has the same physical characteristics and quality with the ceramics made of natural raw materials. In many situations, the final product appears to have the same and better characteristics. Characteristics such as bending strength, compressed strength, water absorption, porosity and other of the ceramics made of wastes, appeared to be better than common ceramics.
Also, in the final chapters we compare these two industries to see the differences and the similarities between them. These differences are a point of further investigation in order to improve the methodology and the amount of waste used. The similarities are the basis to carry on forward with the updating of BATs in the ceramic industry. The most important similarities are the same range of temperatures used, the same relatively chemical constitution of raw materials and the concern about environment protection.
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Επικαιροποίηση των βέλτιστων διαθέσιμων τεχνικών της Κεραμικής βιομηχανίας - Σύγκριση με αντίστοιχες τεχνικές της βιομηχανίας Τσιμέντου - Identifier: 73078
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