Adição de subprodutos da cinza da casca de café (coffea canephora) em massa cerâmica para porcelanato
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 qua...
Wedi'i Gadw mewn:
| Prif Awdur: | |
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| Awduron Eraill: | |
| Fformat: | doctoralThesis |
| Iaith: | por |
| Cyhoeddwyd: |
Universidade Federal do Rio Grande do Norte
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| Pynciau: | |
| Mynediad Ar-lein: | https://repositorio.ufrn.br/jspui/handle/123456789/12834 |
| Tagiau: |
Ychwanegu Tag
Dim Tagiau, Byddwch y cyntaf i dagio'r cofnod hwn!
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| Crynodeb: | 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 Ávila-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 |
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