Caracterização e classificação de resíduo sólido "pó de rocha granítica" gerado na indústria de rochas ornamentais

The ornamental rock industry generates huge amounts of wastes during the process of extraction and sawing of rock blocks. The ornamental rock powder waste is a non-biodegradable material, which represents the increase in environmental problem. The waste was collected from a granitic rock sawing plant located in Santo Antônio de Pádua, Rio de Janeiro. The chemical-environmental characterization and classification of the waste were done according to ABNT standards. The results showed that the granitic rock powder waste should be classified as Class II A - "No Inert", because of its high concentrations of lead, chrome, iron and manganese

Valorization of Municipal Waterworks Sludge to Produce Ceramic Floor Tiles

In municipal waterworks large amounts of waste in the form of sludge have to be discarded. This investigation focuses on the processing of ceramic floor tiles incorporated with a municipal waterworks sludge. Four floor tile formulations containing up to 10 wt. % of the municipal waterworks sludge were prepared in order to replace the kaolin. The floor tile processing route consisted of dry powder granulation, uniaxial pressing, and firing between 1190 and 1250 °C using a fast-firing cycle (<60 min). The densification behavior and technological properties of the floor tile pieces as function of the sludge addition and firing temperature were determined. The development of the microstructure was followed by XRD and SEM/EDS. The results show that the replacement of kaolin with municipal waterworks sludge, in the range up to 10 wt. %, allows the production of ceramic floor tiles (group BIb and group BIIa, ISO 13006 Standard) at lower firing temperatures. These results suggest a new possibility of valorization of municipal waterworks sludge in order to bring economic and environmental benefits

Sintering behavior of porous wall tile bodies during fast single-firing process

In ceramic wall tile processing, fast single-firing cycles have been widely used. In this investigation a fast single-firing porous wall tile mixture was prepared using raw materials from the North Fluminense region.Specimens were obtained by uniaxial pressing and sintered in air at various temperatures (1080 - 1200 °C) using a fast-firing cycle (60 minutes). Evolution of the microstructure was followed by XRD and SEM. The results revealed that the main phases formed during the sintering step are anorthite, gehlenite and hematite. It appears that the sintering process is characterized by the presence of a small amount of a liquid phase below 1140 °C. As a result, the microstructure of the ceramic bodies showed a network of small dense zones interconnected with a porous phase. In addition, the strength of the material below 1140 °C appeared to be related to the type and quantity of crystalline phases in the sintered bodies