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Previous issue date: 2015-01-30 / A produ??o de materiais cer?micos de alumina encontra grandes aplica??es industriais. S?o requeridos para esses produtos, n?veis elevados de desempenhos tecnol?gicos obtidos pelos altos padr?es no processo de fabrica??o. Contudo, ap?s vida ?til, esses s?o geralmente descartados de forma elementar, nem sempre reaproveitados por um processo adequado de gerenciamento de res?duos. No contexto ceramista s?o crescentes as pesquisas direcionadas para a utiliza??o de res?duos na formula??o de massas cer?micas com a finalidade de reduzir quantidades de mat?rias primas convencionais. Objetivando gerar contribui??es cient?fica, tecnol?gica e ambiental, o presente trabalho consistiu na s?ntese da cer?mica beta alumina s?dica (Na-b-Alumina), tendo como materiais de partida o chamote do isolador cer?mico de velas de igni??o inserv?veis, fonte de alfa alumina (a-Al2O3) e o bicarbonato de s?dio (NaHCO3), fonte de ?xido de s?dio (Na2O), obtido do res?duo gerado pelo processo de manuten??o de extintores de inc?ndio do tipo p? qu?mico. A beta alumina s?dica foi obtida a partir de mistura convencional dos ?xidos de alum?nio e s?dio em propor??es molares adequadas. Foi realizada a coleta das velas inserv?veis e tratamentos f?sicos atrav?s de choques mec?nicos, moagem, purifica??o magn?tica, lavagem, secagem e nova moagem a alta energia para a produ??o do p? de chamote, o qual, por evid?ncia, apresentou alto teor de a-alumina (84,34%) constatado por an?lise qu?mica FRX e das fases presentes por DRX. De forma semelhante, an?lises de FRX e DRX constataram elevados teores de ?xido de s?dio (86,62%) no res?duo de p? qu?mico utilizado nos extintores. As etapas do procedimento experimental se seguiram com a defini??o e formula??o qu?mica em base molar dos materiais de partida (1:9; 1:10 e 1:11 Na2O/Al2O3), inclus?o de aditivos, par?metros de moagem, an?lise granulom?trica, dilatometria, conforma??o dos corpos de prova, sinteriza??o e caracteriza??o do produto final atrav?s de an?lises f?sica de absor??o de ?gua, porosidade aparente, retra??o linear, DRX e MEV. Os produtos cer?micos obtidos na temperatura de queima a 1.200 oC e base molar de 1:10 (Na2O/Al2O3), evidenciaram maior presen?a da fase beta alumina s?dica, em presen?a de uma segunda fase (a-alumina), com propriedades dentro dos par?metros t?cnicos exigidos. A partir dos resultados obtidos, foram propostos novos estudos e aplica??es na confec??o cer?micas utilizadas em equipamentos laborat?rios, sensores de gases e componentes el?tricos, dentro outros. / Ceramic materials the alumina base are large industrial applications. They are required for these products, specific characteristics obtained by following strict criteria during the manufacturing process. However, after life, not always these products are reused by a suitable waste management process. In ceramist context, advance research aimed at the reuse of waste aimed at obtaining ceramics and composite materials, with marked reduction of conventional raw materials. Aiming to generate scientific, technological and environmental contribution, this work studied to obtain a composite of alumina ceramic (Al2O3) and sodium beta alumina (NaAl11O17 ), and as starting materials the residue of the ceramic insulator of spark plugs, as a source alumina (Al2O3) powder and unusable sodium bicarbonate (NaHCO3) of fire extinguishers, as a source of sodium oxide (Na2O). The final ceramic product was obtained from a conventional mixture of sodium aluminum oxide in appropriate molar proportions. Sample spark plugs were obtained, discarded by lifetime, specific to a manufacturer, which, after passing through mechanical stress (grinding, magnetic purification, washing, drying and grinding the high energy), which resulted in residue powder with ceramic content of 84.34 % alumina (Al2O3), found by FRX chemical analysis, the phases present and identified by DRX. The dry chemical fire extinguisher, baking soda-based (NaHCO3) with expired, was obtained through direct collection of the waste generated during maintenance. Subjected to heat treatment at 120 ?C , the NaHCO3 powder was decomposed in sodium oxide ( Na2O), which, subjected to chemical analysis (FRX) and mineralogical (DRX) revealed a content of 86.62 % sodium oxide (Na2O) . In the following steps the experimental procedure, chemical formulations were made on a molar basis of the starting material (1:9, 1:10 and 1:11 de Na2O/ Al2O3) inclusion of additives, milling parameters, sieve analysis, dilatometry, conformation of specimens, sintering in firing steps at 800 ?C , 1000 ?C and 1.200 ?C with varying stays 30 , 60 and 120 minutes in each of the levels. The characterization of the final product was made by the following physical tests: water absorption, porosity, linear shrinkage, mineralogical analysis by DRX and microstructural analysis by MEV. A higher formation of sodium beta alumina (NaAl11O17), in sintered specimens in levels of 1.200 ?C and 120 minutes, despite the prevailing coexistence of alpha phase alumina (Al2O3). From the results obtained opens up prospects for the reuse of waste studied in this work, the potter context and in other technological areas.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21131 |
| Date | 30 January 2015 |
| Creators | Palma, Aldemiro Jos? Rocha |
| Contributors | 06296687877, http://lattes.cnpq.br/2365059843175411, Macedo, Daniel Ara?jo de, 01152094416, http://lattes.cnpq.br/1027496814443777, Dultra, Eduardo Jorge Vidal, 02551707692, http://lattes.cnpq.br/2132307633780425, Nascimento, Rubens Maribondo do, 80732810400, http://lattes.cnpq.br/8671649752936793, Marinho, George Santos, Paskocimas, Carlos Alberto |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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