| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 2.69 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
O acesso a matérias-primas não energéticas, como os materiais necessários para o fabrico de refratários, tem-se revelado um problema para a UE e a maioria dos países desenvolvidos. Muitos destes materiais existem apenas em alguns países, sendo estes na sua maioria emergentes e onde existe em certos casos instabilidade política e socioeconómica. Para garantir o acesso a estas matérias-primas, a UE lançou em 2008 a “Raw materials Iniciative” onde um dos três pilares em que se baseia é a reciclagem. Deste modo é possível diminuir o consumo de matérias-primas e diminuir a dependência das importações.
Neste trabalho foram caracterizados os resíduos de desmantelamento do revestimento refratário de um conversor de aço. Após a moagem dos resíduos prepararam-se amostras com composições otimizadas da fração contaminada e não contaminada e comparadas as suas propriedades mecânicas, físicas e termodinâmicas com a matéria-prima original. Para tal, corpos de prova dos resíduos e da matéria-prima original foram construídos por compressão, onde a distribuição granulometria da mistura dos resíduos refratários foi previamente otimizada com o objetivo de se assemelhar à matéria-prima comercial, e sinterizados à temperatura de 1200, 1350 e 1500C ºC.
Foram realizados ensaios de caracterização mecânica de flexão em três pontos e compressão uniaxial para as várias composições e temperaturas de sinterização. As propriedades físicas foram avaliadas através de ensaios de porosidade, absorção de água e densidade. Por fim, a microestrutura dos diferentes corpos de prova foi analisada em SEM e DRX de modo a verificar quais as fases presentes em função da temperatura de sinterização.
Finalmente, discute-se a viabilidade de reciclar e valorizar os resíduos refratários de desmantelamento como um novo material (matéria-prima), atribuindo-lhe uma outra utilidade comercial.
The access to non-energetic raw materials, such as the necessary materials to refractories manufacturing, has become a major problem to the EU and most of the developed countries. Many of these materials exist in a few countries, being these in general emerging countries where in certain cases there are political and socioeconomic instabilities. In order to ensure a secure access to the raw materials, the EU launched in 2008 the “Raw materials iniciative” where one of the three pillars is recycling. In this way, it’s possible to decrease the raw materials consumption as well as imports dependence. In this work, the characterization of the dismantled refractory waste lining of a steel converter has been made. After milling of the waste, specimens with optimized compositions of contaminated and non-contaminated fractions, were prepared and compared with the mechanical, physical and thermodynamics properties of the original raw material. For that, specimens of the refractory waste and original raw material were built by compression, where the granulometric distribution of the waste refractory mix was previously optimized with the aim to become similar to the commercial raw material, and sinterized at temperatures of 1200, 1350 and 1500°C. Mechanic characterization tests such as three point bending and uniaxial compression have been made for the several compositions and sintering temperatures. The physical properties were assessed by porosity tests, water absorption and density. Then, the microstructure of the different specimens was analyzed using SEM and DRX techniques, in order to verify which phases are present in function of the sintering temperature. Finally, is discussed the viability of recycling and add value to those dismantled waste, as a new material (raw material) giving it another commercial purpose.
The access to non-energetic raw materials, such as the necessary materials to refractories manufacturing, has become a major problem to the EU and most of the developed countries. Many of these materials exist in a few countries, being these in general emerging countries where in certain cases there are political and socioeconomic instabilities. In order to ensure a secure access to the raw materials, the EU launched in 2008 the “Raw materials iniciative” where one of the three pillars is recycling. In this way, it’s possible to decrease the raw materials consumption as well as imports dependence. In this work, the characterization of the dismantled refractory waste lining of a steel converter has been made. After milling of the waste, specimens with optimized compositions of contaminated and non-contaminated fractions, were prepared and compared with the mechanical, physical and thermodynamics properties of the original raw material. For that, specimens of the refractory waste and original raw material were built by compression, where the granulometric distribution of the waste refractory mix was previously optimized with the aim to become similar to the commercial raw material, and sinterized at temperatures of 1200, 1350 and 1500°C. Mechanic characterization tests such as three point bending and uniaxial compression have been made for the several compositions and sintering temperatures. The physical properties were assessed by porosity tests, water absorption and density. Then, the microstructure of the different specimens was analyzed using SEM and DRX techniques, in order to verify which phases are present in function of the sintering temperature. Finally, is discussed the viability of recycling and add value to those dismantled waste, as a new material (raw material) giving it another commercial purpose.
Description
Keywords
Matérias-Primas Propriedades Mecânicas. Reciclagem Refratários Resíduos de Desmantelamento