| Resumo: |
This work aims to investigate the incorporation of waste lime mud, generated by the pulp industry, in the formulations of the porous ceramic body in substitution the raw material calcite. The experiments covered the physico-chemical and mineralogical of the raw materials, the waste, and the compositions proposals. It was verified that the residue has the carbonate content slightly larger than the calcite, a larger average particle size and similar thermal properties. The ceramic bodies studied were prepared by the wet process, conformed by uniaxial pressing and sintered in an industrial furnace at 1135 °C and laboratory at temperatures of 1115 °C, 1125 °C, 1135 °C and 1145.°C with sintering cycle fast. Then, technological tests were carried total shrinkage, absorption of water, loss on ignition, mechanical strength and colorimetric coordinate. It was observed that, with the increase in substitution of calcite for the residue lime mud, the total shrinkage test samples decreased, while increasing the dimensional stability. Thus, other formulations have been proposed with the objective of keeping the shrinkage closest to standard composition. Compositions were selected, tested and characterized by differential thermal analysis and thermogravimetryc analysis, dilatometry and microstructure analysis of the fracture of the sintered specimens. The results shown to be possible to use waste "lime mud" in wall tiles compositions as a substitute for raw material calcite, keeping requirements of the NBR 13818, and with the advantage of reducing the percentage of carbonates in the composition, increased dimensional stability during sintering, lighten the color of ceramic body, addition to being an environmental solution. |
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