Characterization of water treatment sludge and clay: feasibility in the manufacture of ceramic artifacts

Reference	Presenter	Authors (Institution)	Abstract
16-021	Felipe Pires Chaves	Chaves, F.P.(Centro Universitário Antônio Eufrásio de Toledo); Barga, L.(Centro Universitário Antônio Eufrásio de Toledo); Teixeira, S.R.(Universidade Estadual Paulista); Reis, E.A.(UNESP);	This work presents the characterizations of the sludge from the water treatment plant of Presidente Prudente/SP and clays used for ceramic artifacts manufacturing in the city of Indiana/SP, in order to verify the possibility of using these materials for the production of artifacts applicable in construction. Sludge and clay samples were submitted to thermogravimetric (TG) and thermodifferential (DTA) analyzes, differential scanning calorimetry (DSC) and X-ray diffraction. In all thermal analyzes, the heating rate conditions were maintained at 20 ºC/min, with alumina crucibles and air atmosphere. In the thermal analyzes, an endothermic peak is observed at approximately 95 ºC in both sludge and clay samples. This peak is probably related to the loss of free water from the samples. Between 200 and 350 ºC, exothermic events in the samples are identified, probably related to the degradation of organic matter or the loss of water related to the decomposition of hydroxides. Around 500 ºC, a well-defined endothermic event is observed related to the dehydroxylation reactions of kaolinite, present in clay and sludge, forming metakaolinite, accompanied by great loss of mass in the samples. Another exothermic peak can be identified around 950 ºC, justified by the possible dissociation of metakaolinite. The X-ray diffraction analysis showed that in clay and sludge analyzed there is predominance of quartz and kaolinite. This fact indicates a noteworthy similarity between the residue and the clays used for ceramics manufacturing, which demonstrates the possible substitution of the non-renewable raw material for the residue.
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