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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo da obten??o de cer?mica composta de alumina e beta alumina s?dica utilizando-se res?duo cer?mico de velas de igni??o e p? qu?mico de extintores de inc?ndio

Palma, Aldemiro Jos? Rocha 30 January 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-09T22:34:12Z No. of bitstreams: 1 AldemiroJoseRochaPalma_TESE.pdf: 1984561 bytes, checksum: b3a56954198f95830b50a6c91ccef3bc (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-10T20:49:38Z (GMT) No. of bitstreams: 1 AldemiroJoseRochaPalma_TESE.pdf: 1984561 bytes, checksum: b3a56954198f95830b50a6c91ccef3bc (MD5) / Made available in DSpace on 2016-08-10T20:49:38Z (GMT). No. of bitstreams: 1 AldemiroJoseRochaPalma_TESE.pdf: 1984561 bytes, checksum: b3a56954198f95830b50a6c91ccef3bc (MD5) 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.
2

Adi??o de chamote de velas de igni??o inserv?veis na obten??o de cer?mica branca a base de alumina

Palma, Aldemiro Jos? Rocha 21 January 2010 (has links)
Made available in DSpace on 2014-12-17T14:57:59Z (GMT). No. of bitstreams: 1 AldemiroJRP_DISSERT.pdf: 1779400 bytes, checksum: 8a5467983a7427bc6b96f7baa7868609 (MD5) Previous issue date: 2010-01-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work presents research into the addition of chamotte obtained from the ceramic isolator of unusable spark plugs in formulations of material mixes for standard white ceramic material with aluminum oxide bases. After the physical chemical characterization of the primary materials, standard clay and the chamotte, three mixtures were prepared with concentrations of 10, 20 and 30% chamotte by weight in relation to the standard clay. The test samples underwent heating at a rate of 30 0C/min to levels that included 100o , 200o , 300o, 400o, 500o e 600 0C and also we submitted to three distinct burn temperatures: 1450o, 1500o e 1550 0C, remaining at these temperatures for 2 hour periods. After sintering, the physical and microstructural properties of the different test samples were measured and analyzed. The results show that the materials obtained present good technical properties and that the chamotte can be reutilized as an additive in the production of white ceramic material with an aluminum oxide base / Neste trabalho estudou-se a influ?ncia da adi??o de chamote obtido do isolador cer?mico de velas de igni??o inserv?veis na formula??o de massas de cer?mica branca a base de alumina. Ap?s caracteriza??o f?sico-qu?mica das mat?rias-primas, argila-padr?o e chamote, foram preparadas tr?s formula??es de concentra??es 10, 20 e 30% em peso de chamote em rela??o ? argila-padr?o. Os corpos-de-prova foram submetidos ao aquecimento numa taxa de 30 0C/min em patamares de 100? , 200? , 300? , 400? , 500? e 600 0C e queimados em tr?s temperaturas distintas a 1450? , 1500? e 1550 0C, permanecendo 2 horas na temperatura de patamar. Ap?s as sinteriza??es, as propriedades f?sicas e a evolu??o microestrutural de fases dos corpos-de-prova foram mensuradas e discutidas. Os resultados mostraram que os materiais obtidos apresentam boas propriedades e que o chamote pode ser reaproveitado como aditivo na produ??o de cer?micas brancas a base de alumina

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