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Previous issue date: 2013-05-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / To produce porcelain tiles fluxing agents are used in order to obtain a liquid phase
during firing. This liquid phase fills the pores decreasing porosity, water absorption
and contributes to material densification. In the porcelain tiles industry, feldspar is the
main flux material used, with quantities ranging between 35 and 50%. Studies focus
on the discovery of materials with flux characteristics that can reduce the
consumption of feldspar by porcelain tiles industry. In this context, the coffee husk
ashes, a residue obtained when coffee husks are burned to produce heat for the
dryers during the processing of the green fruit, have as main chemical constituents
potassium, calcium and magnesium, giving them characteristics of fluxing material.
Brazil is the largest coffee producer in the world and is responsible for over 30% of
the world s production. In this work a physical treatment of coffee husk ash was
carried out in order to eliminate the organic matter and, after this, two by-products
were obtained: residual wastes R1 and R2. Both residues were added separately as
single fluxes and also in association with feldspar in mixtures with raw materials
collected in a porcelain industry located in Dias d ?vila-Ba. The addition of these
residues aimed to contribute to the reduction of the consumption of feldspar in the
production of porcelain tiles. Specimens were produced with dimensions of 60 mm x
20 mm x 6 mm in an uniaxial die with compacting pressure of 45 MPa. The samples
were heated to a temperature of 1200 ?C, for 8 minutes. Tests were performed to
characterize the raw materials by XRF, XRD, particle size analysis, DTA and TGA
and, additionally, the results of the physical properties of water absorption, apparent
porosity, linear shrinkage, density, dilatometry, flexural strength and SEM of sintered
body were analyzed. Additions of less than 8% of the residue R1 contributed to the
decrease of porosity, but the mechanical strength of the samples was not
satisfactory. Additions of 5% the R2 residue contributed significantly to decrease the
water absorption and apparent porosity, and also to increase the mechanical
strength. Samples with addition of feldspar associated with the R2 residue, in
proportions of 6.7% of R2 and 6.7% of feldspar, led to results of water absorption of
0.12% and mechanical strength of 46 MPa, having parameters normalized to the
manufacture of porcelain stoneware tiles / Na fabrica??o de porcelanatos s?o utilizados fundentes com a finalidade de obter
fase l?quida durante a queima que, por sua vez, preenche os poros diminuindo a
porosidade, a absor??o de ?gua, e contribui para a densifica??o do material. Na
ind?stria de porcelanatos o feldspato ? o principal material fundente utilizado, com
percentuais que variam entre 35 e 50% em massa. Pesquisas s?o direcionadas para
a descoberta de materiais com caracter?sticas fundentes que possam diminuir o
consumo de feldspato. Nesse contexto, a cinza da casca de caf?, res?duo obtido
quando cascas de caf? s?o queimadas a fim de produzir calor para os secadores
mec?nicos durante o beneficiamento do fruto, possuem como principais elementos o
pot?ssio, c?lcio e magn?sio, conferindo-lhe caracter?sticas de material fundente. O
Brasil ? o maior produtor de caf? do mundo, respons?vel por mais de 30% da
produ??o mundial. Nesse trabalho, foi realizado um tratamento f?sico na cinza de
caf? com a finalidade de eliminar parte do material carbonizado e, ap?s este, foram
obtidos dois subprodutos: res?duo R1 e res?duo R2. Ambos os res?duos foram
adicionados, separadamente, como ?nicos fundentes, e tamb?m associados ao
feldspato, em massas com mat?rias primas coletadas em uma f?brica de
porcelanatos localizada no munic?pio de Dias d ?vila-Ba. A adi??o desses res?duos
teve o objetivo de verificar a possibilidade de reduzir o consumo de feldspato na
produ??o de porcelanatos. Foram confeccionados corpos de prova com dimens?es
de 60 mm x 20 mm x 6 mm em matriz uniaxial, com press?o de compacta??o de 45
MPa. Os corpos de prova foram sinterizados na temperatura de 1200 ?C com
patamar de 8 minutos. Foram realizados ensaios para caracteriza??o das mat?riasprimas
por FRX, DRX, AG, ATD e ATG, e analisados os resultados das propriedades
f?sicas de absor??o de ?gua, porosidade aparente, retra??o linear, MEA, an?lise
dilatom?trica, resist?ncia ? flex?o e MEV do corpo sinterizado. A adi??o de at? 8%
do res?duo R1 contribuiu para a diminui??o da porosidade aparente, por?m a
resist?ncia mec?nica das amostras n?o foi satisfat?ria. A adi??o de 5% de res?duo
R2 contribuiu significativamente para diminuir absor??o de ?gua e porosidade
aparente, e tamb?m, para o aumento da resist?ncia mec?nica ? flex?o. As amostras
com adi??o do res?duo R2 associado ao feldspato, nas propor??es de 6,7% de R2 e
6,7% de feldspato, obtiveram resultados de absor??o de ?gua de 0,12% e
resist?ncia mec?nica ? flex?o de 46 MPa, atendendo aos par?metros normalizados
para fabrica??o de porcelanatos
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12834 |
| Date | 23 May 2013 |
| Creators | Dultra, Eduardo Jorge Vidal |
| Contributors | CPF:50580396720, http://lattes.cnpq.br/5460040602567184, Gomes, Cynthia Morais, CPF:02555125469, http://lattes.cnpq.br/1441106728967011, Silva, Jaquel?gia Brito da, CPF:02585622428, http://lattes.cnpq.br/5948828937239319, Silva, Vamberto Monteiro da, CPF:67456863415, Acchar, Wilson |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia de Materiais, UFRN, BR, Processamento de Materiais a partir do P?; Pol?meros e Comp?sitos; Processamento de Materiais a part |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| 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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