Recycling of Firewood Ash Waste in Ceramic Floor Tiles with Low Water Absorption

This work aims to evaluate the recycling of firewood ash waste as a procedure to provide sustainable raw material for ceramic floor tiles with low water absorption. For this purpose, firewood ash waste coming from a red ceramic company in Campos dos Goytacazes-RJ (Brazil) was selected as an alternative raw material into a ceramic floor tile body, replacing natural quartz material by up to 10 wt.%. Floor tile pieces containing up to 10 wt.% of firewood ash waste were prepared by the dry process, pressed, and fired between 1190 & DEG;C and 1250 & DEG;C using a fast-firing cycle. The floor tile pieces were tested to determine their properties (linear shrinkage, water absorption, apparent porosity, apparent density, and flexural strength). The results showed that the partial replacement of quartz with firewood ash waste, in the range up to 10 wt.%, allows the production of ceramic floor tiles with low water absorption (WA) (BIa group - WA < 0.5% and BIb group - 0.5 < WA & LE; 3%; ABNT NBR ISO 13006:2020 Standard) in different amounts of firewood ash waste at lower firing temperatures.