Evaluation of the suitability of municipal waterworks waste as a raw material for red ceramic bricks production

Abstract

In waterworks large amounts of sludge have to be discarded.This waste is usually destined to rivers, lakes and landfills, resulting in economic and environmental problems. This work reports on the use of waste (sludge) of a waterworks from South-Eastern Brazil as a raw material in red ceramic.The waste sample was characterized regarding crystalline phases, chemical composition, morphology, cation exchange capacity and particle size. In addition, leaching and solubilization tests were performed. Ceramic pieces containing up to 15 wt.% of waterworks waste powder were prepared by uniaxial pressing and sintered at 950 ºC.The effects of the waste addition on linear shrinkage, water absorption, apparent density, and flexural strength have been determined.The sintered microstructure was evaluated by scanning electron microscopy.The results showed that the municipal waterworks waste could be used for red bricks production, resulting in a new possibility for the recycling of this waste as well as natural resources conservation.