Effect of the firing temperature on the technical properties of clay ceramic added with blast furnace sludge waste

Abstract This work reports a study on the effects of firing temperature on the technical properties of clay ceramic incorporated with blast furnace sludge (BFS) waste. For this, three clay ceramic pastes were formulated, partially replacing plastic clay with up to 10 wt.% of BFS waste. The clay ceramic pieces were shaped by pressing and fired in a muffle furnace between 900 ºC and 1100 ºC. The effect of firing temperature was evaluated by monitoring linear shrinkage, water absorption, apparent porosity, apparent density, and flexural strength. The BFS waste consists mainly of iron oxide (Fe2O3) and coke fines. It was also found that the firing temperature influenced the technical properties, resulting in relevant repercussions on the quality of the clay ceramic pieces incorporated with BFS waste. The results allowed us to conclude that sealing and structural ceramic blocks for masonry can be produced at firing temperatures between 900 ºC and 1000 ºC, while roofing tiles can be made at 1100 ºC.