Estudo da adição de resíduos de quartzitos para obtenção de grés porcelanato
In States of Paraíba (PB) and Rio Grande do Norte (RN), northeast of Brazil, the most significant deposits of non-metallic industrial minerals are pegmatites, quartzites and granites, which are located in Seridó region. Extraction of clay, quartz, micas and feldspars occurs mainly in the cities o...
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| Formato: | doctoralThesis |
| Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/20228 |
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| Resumo: | In States of Paraíba (PB) and Rio Grande do Norte (RN), northeast of Brazil, the most
significant deposits of non-metallic industrial minerals are pegmatites, quartzites and granites,
which are located in Seridó region. Extraction of clay, quartz, micas and feldspars occurs
mainly in the cities of Várzea (PB), OuroBranco (RN) and Parelhas (RN). Mining companies
working in the extraction and processing of quartzite generate large volumes of waste
containing about 90% SiO2 in their chemical composition coming from quartz that is one of
the basic constituents of ceramic mass for the production of ceramic coating. Therefore, this
work evaluates the utilization of these wastes on fabrication of high-quality ceramic products,
such as porcelain stoneware, in industrial scale. Characterization of raw materials was based
on XRF, XRD, GA, TGA and DSC analysis, on samples composed by 57% of feldspar, 37%
of argil and 6% of quartzite residues, with 5 different colors (white, gold, pink, green and
black). Samples were synthesized in three temperatures, 1150°C, 1200°C and 1250°C, with
one hour isotherm and warming-up tax of 10°C/min. After synthesizing, the specimens were
submit to physical characterization tests of water absorption, linear shrinkage, apparently
porosity, density, flexural strain at three points. The addition of 6% of quartzite residue to
ceramic mass provided a final product with technological properties attending technical norms
for the production of porcelain stoneware; best results were observed at a temperature of
1200°C. According to the results there was a high iron oxide on black quartzite, being their
use in porcelain stoneware discarded by ethic and structural question, because the material
fused at 1250°C. All quartzite formulations had low water absorption when synthesized at
1200°C, getting 0.1% to 0.36% without having gone through the atomization process.
Besides, flexural strain tests overcame 27 MPa reaching the acceptance limits of the European
Directive EN 100, at 1200°C synthesizing. Thus, the use of quartzite residues in ceramic
masses poses as great potential for the production of porcelain stoneware. |
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