Manufacture of Ceramic Bricks Using Recycled Brewing Spent Kieselguhr

Abstract

In the brewing process, kieselguhr performs as a filtration medium and one generated by-product is a sludge containing kieselguhr, which is mainly composed of fragmented diatom frustules associated to organic material retained during the clarification process.

The physic-mechanic tests were performed on assemblages with brick composition and brewing spent kieselguhr containing 3, 9, and 15 wt% incorporation levels of sludge, being extruded and dried (105°C) before being submitted to slow firing at 900°C, 950°C, and 1000°C.

The obtained results showed that, even when at its maximum incorporation level, the spent kieselguhr for all firing temperatures do not cause important losses on the properties exhibited by the clay paste without kieselguhr incorporation and the best incorporation levels are 4.2 wt% when fired at 900°C, 9.8 wt% when fired at 950°C, and 13.4 wt% when fired at 1000°C. When fired at 950°C, 15 wt% addition of spent kieselguhr increased by 27% the open porosity and decreased by 10% the bulk density of the brick paste.

Furthermore, physic-mechanic tests and ecotoxicity evaluation on semi-industrial brick manufactured with 9 wt% of brewing spent kieselguhr were accessed. The results do no show any constrain concerning mechanical properties, and the ecotoxicity evaluation shows the safety of the brewing spent kieselguhr incorporation in ceramic products.

Keywords:

• Brewing
• Brick
• By-product
• Ceramics
• Density
• Diatomite
• Ecotoxicity
• Kieselguhr
• Recycling

ACKNOWLEDGMENT

The authors are grateful to Sociedade Central de Cervejas e Bebidas, S.A. (Vialonga, Portugal) for the valuable support and assistance provided.

Notes

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