Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão
Autor(a) principal: | |
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Data de Publicação: | 2013 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/889 |
Resumo: | The addition of magnesium-aluminate spinel (MgAl2O4) in refractories for secondary steel refining has been considered for years one of the more feasible alternatives to reduce the corrosive wear imposed by the aggressive steel ladle environment. Nonetheless, the corrosion resistance of spinel refractory castables is still not fully understood, mainly regarding to the influence of chemical and microstructural characteristics of such materials. This aspect is basically related to: 1) the limited knowledge on the castable microstructural evolution with temperature and, 2) the usual evaluation of commercial products with unknown compositions. In order to overcome this drawback, the main objective of the present project is to understand the microstructural behavior of spinel refractories during sintering and, as a consequence, how the generated microstructure interacts with basic slags at high temperatures. The slag penetration into these materials was clearly associated not only with the sort of incorporated spinel (pre-formed or in situ), but mainly to the previous location of crystals of an additional phase, the calcium hexaluminate (CaO.Al2O3 - CA6) one. When present at the border of the aggregates, CA6 grains provide a suitable protection of the castable structure during the interaction with molten slag, suppressing further infiltrations. Additionally, materials with reduced apparent porosity and average pore size also presented high corrosion resistance. Based on this information, high performance refractories were obtained by a better raw materials selection procedure. The colloidal alumina addition, for instance, resulted in a microstructure with favorable physical aspects, whereas the presence of in situ spinel led to CA6 further generation at target locations. The attained results disclose novel opportunities to produce refractory castable with excellent corrosion resistance, which may reduce the failures rate during operation and increase the steel ladle productivity. |
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Sako, Eric YoshimitsuPandolfelli, Victor Carloshttp://lattes.cnpq.br/7369376873984839http://lattes.cnpq.br/8928860067817842f95ee17e-434d-4afd-8570-6677194213582016-06-02T19:12:26Z2013-02-272016-06-02T19:12:26Z2013-10-04SAKO, Eric Yoshimitsu. Spinel refractory castables: microstructural design and corrosion evaluation. 2013. 153 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2013.https://repositorio.ufscar.br/handle/ufscar/889The addition of magnesium-aluminate spinel (MgAl2O4) in refractories for secondary steel refining has been considered for years one of the more feasible alternatives to reduce the corrosive wear imposed by the aggressive steel ladle environment. Nonetheless, the corrosion resistance of spinel refractory castables is still not fully understood, mainly regarding to the influence of chemical and microstructural characteristics of such materials. This aspect is basically related to: 1) the limited knowledge on the castable microstructural evolution with temperature and, 2) the usual evaluation of commercial products with unknown compositions. In order to overcome this drawback, the main objective of the present project is to understand the microstructural behavior of spinel refractories during sintering and, as a consequence, how the generated microstructure interacts with basic slags at high temperatures. The slag penetration into these materials was clearly associated not only with the sort of incorporated spinel (pre-formed or in situ), but mainly to the previous location of crystals of an additional phase, the calcium hexaluminate (CaO.Al2O3 - CA6) one. When present at the border of the aggregates, CA6 grains provide a suitable protection of the castable structure during the interaction with molten slag, suppressing further infiltrations. Additionally, materials with reduced apparent porosity and average pore size also presented high corrosion resistance. Based on this information, high performance refractories were obtained by a better raw materials selection procedure. The colloidal alumina addition, for instance, resulted in a microstructure with favorable physical aspects, whereas the presence of in situ spinel led to CA6 further generation at target locations. The attained results disclose novel opportunities to produce refractory castable with excellent corrosion resistance, which may reduce the failures rate during operation and increase the steel ladle productivity.A adicao de espinelio de magnesia e alumina (MgAl2O4) em refratarios para metalurgia secundaria tem sido considerada ha anos uma das alternativas mais viaveis para reduzir o desgaste corrosivo imposto pelo ambiente agressivo de panelas de aco. No entanto, tais conclusoes sao obtidas sem considerar plenamente como os aspectos quimicos e microestruturais de concretos refratarios contendo espinelio influenciam sua resistencia a corrosao. Isto se deve basicamente a dois fatores: o conhecimento limitado em relacao a evolucao microestrutural do refratario com a temperatura e a realizacao de analises em materiais comerciais, cujas composicoes sao desconhecidas. Visando suprimir essa lacuna, o presente projeto tem como principal objetivo entender de forma sistemica o comportamento microestrutural de refratarios espinelizados durante a sinterizacao e, consequentemente, como esta microestrutura gerada interage com escorias basicas em temperaturas elevadas. Observou-se que os niveis de penetracao de escoria nesses materiais estao associados nao so as caracteristicas do tipo de espinelio utilizado (pre-formado ou in situ), mas principalmente a localizacao previa dos cristais de outra fase formada durante o tratamento termico: o hexaluminato de calcio (CaO.Al2O3 - CA6). Quando presente ao redor dos agregados do concreto, os graos de CA6 promovem uma protecao satisfatoria da estrutura durante o contato com a escoria liquida, reduzindo o avanco da infiltracao. Adicionalmente, materiais contendo valores reduzidos de porosidade e tamanho medio de poro tambem apresentaram elevada resistencia a corrosao. Baseado nessas informacoes, foi possivel obter refratarios de elevado desempenho por meio da correta selecao de materias-primas. A adicao de alumina coloidal, por exemplo, gerou uma microestrutura com aspectos fisicos mais favoraveis, enquanto a presenca de espinelio formado in situ levou a geracao subsequente de CA6 nas regioes desejadas. Esses resultados abrem novas oportunidades para a producao de concretos refratarios de excelente resistencia a corrosao, possibilitando a reducao no numero de falhas durante a operacao e o aumento na produtividade das panelas de aco.Universidade Federal de Sao Carlosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEMUFSCarBRMateriais refratáriosEspinélioConcretos refratáriosCorrosãoENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICAConcretos refratários espinelizados : projeto da microestrutura e análise da corrosãoSpinel refractory castables: microstructural design and corrosion evaluationinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesis-1-1390bd4d1-c505-4015-b043-b075d197c61finfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL4879.pdfapplication/pdf25673246https://repositorio.ufscar.br/bitstream/ufscar/889/1/4879.pdf6c3e0d5feb6e463144ee2d5d5e50882fMD51TEXT4879.pdf.txt4879.pdf.txtExtracted texttext/plain0https://repositorio.ufscar.br/bitstream/ufscar/889/2/4879.pdf.txtd41d8cd98f00b204e9800998ecf8427eMD52THUMBNAIL4879.pdf.jpg4879.pdf.jpgIM Thumbnailimage/jpeg6212https://repositorio.ufscar.br/bitstream/ufscar/889/3/4879.pdf.jpg5d68701eb6a9ba3dbc2b51520236b46aMD53ufscar/8892023-09-18 18:31:28.184oai:repositorio.ufscar.br:ufscar/889Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:28Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
dc.title.alternative.eng.fl_str_mv |
Spinel refractory castables: microstructural design and corrosion evaluation |
title |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
spellingShingle |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão Sako, Eric Yoshimitsu Materiais refratários Espinélio Concretos refratários Corrosão ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA |
title_short |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
title_full |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
title_fullStr |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
title_full_unstemmed |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
title_sort |
Concretos refratários espinelizados : projeto da microestrutura e análise da corrosão |
author |
Sako, Eric Yoshimitsu |
author_facet |
Sako, Eric Yoshimitsu |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/8928860067817842 |
dc.contributor.author.fl_str_mv |
Sako, Eric Yoshimitsu |
dc.contributor.advisor1.fl_str_mv |
Pandolfelli, Victor Carlos |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/7369376873984839 |
dc.contributor.authorID.fl_str_mv |
f95ee17e-434d-4afd-8570-667719421358 |
contributor_str_mv |
Pandolfelli, Victor Carlos |
dc.subject.por.fl_str_mv |
Materiais refratários Espinélio Concretos refratários Corrosão |
topic |
Materiais refratários Espinélio Concretos refratários Corrosão ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA |
description |
The addition of magnesium-aluminate spinel (MgAl2O4) in refractories for secondary steel refining has been considered for years one of the more feasible alternatives to reduce the corrosive wear imposed by the aggressive steel ladle environment. Nonetheless, the corrosion resistance of spinel refractory castables is still not fully understood, mainly regarding to the influence of chemical and microstructural characteristics of such materials. This aspect is basically related to: 1) the limited knowledge on the castable microstructural evolution with temperature and, 2) the usual evaluation of commercial products with unknown compositions. In order to overcome this drawback, the main objective of the present project is to understand the microstructural behavior of spinel refractories during sintering and, as a consequence, how the generated microstructure interacts with basic slags at high temperatures. The slag penetration into these materials was clearly associated not only with the sort of incorporated spinel (pre-formed or in situ), but mainly to the previous location of crystals of an additional phase, the calcium hexaluminate (CaO.Al2O3 - CA6) one. When present at the border of the aggregates, CA6 grains provide a suitable protection of the castable structure during the interaction with molten slag, suppressing further infiltrations. Additionally, materials with reduced apparent porosity and average pore size also presented high corrosion resistance. Based on this information, high performance refractories were obtained by a better raw materials selection procedure. The colloidal alumina addition, for instance, resulted in a microstructure with favorable physical aspects, whereas the presence of in situ spinel led to CA6 further generation at target locations. The attained results disclose novel opportunities to produce refractory castable with excellent corrosion resistance, which may reduce the failures rate during operation and increase the steel ladle productivity. |
publishDate |
2013 |
dc.date.available.fl_str_mv |
2013-02-27 2016-06-02T19:12:26Z |
dc.date.issued.fl_str_mv |
2013-10-04 |
dc.date.accessioned.fl_str_mv |
2016-06-02T19:12:26Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
SAKO, Eric Yoshimitsu. Spinel refractory castables: microstructural design and corrosion evaluation. 2013. 153 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2013. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/889 |
identifier_str_mv |
SAKO, Eric Yoshimitsu. Spinel refractory castables: microstructural design and corrosion evaluation. 2013. 153 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2013. |
url |
https://repositorio.ufscar.br/handle/ufscar/889 |
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por |
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openAccess |
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Universidade Federal de São Carlos |
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Programa de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEM |
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UFSCar |
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BR |
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Universidade Federal de São Carlos |
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