The effect of incorporation of red mud on the properties of clay ceramic bodies

Red mud (RM) by-product of Bayer process was added to clay in different proportions to prepare ceramic bodies and the physical properties of the clay ceramic bodies, bulk density, loss on ignition, sintering shrinkage, water absorption and compressive strength were determined. The optimum preparation condition was determined, and the corresponding influence mechanisms were discussed. Due to the high alkalinity and water absorption, RM obviously influenced the properties of clay ceramic bodies, and the optimum parameters were selected as firing temperature of 1050 °C, firing time of 2 h and RM content of 20%. During sintering some components of the raw materials transformed into other crystals, and the color changes of ceramic bodies mainly depended on hematite and magnetite. The glass formed at high temperature improved spalling resistance of the ceramic bodies.

► The best conditions were red mud content of 20% and sintering at 1050 °C for 2 h.
► Red mud’ effects were caused by its high alkalinity and water-retaining property.
► Ceramic bodies' color depended on the relative content of hematite and magnetite.
► Large amount of glass phase can prevent the ceramic bodies from spalling.