Preparation of building ceramic bricks using waste residue obtained by mutual treatment of electrolytic manganese residue and red mud

The waste residue (ER) obtained by the mutual treatment of electrolytic manganese residue and red mud. ER is a kind of silicon and aluminum waste residue with low pollution. In order to alleviate the shortage of silicon-aluminum raw materials in ceramic bricks industry. In this paper, ER is used as a part of silicon-aluminum raw material to prepare building ceramic bricks. The results show that the impurity ions (Fe3+, Na+, K+, etc.) in ER can promote the formation of liquid phase during the calcination process. This makes the ceramic bricks can be successfully fired at 1150 °C. The mineral composition of ceramic bricks prepared by ER is anorthite, quartz, corundum, mullite and glass phase, and the corresponding contents are 40.31 wt%, 2.48 wt%, 6.81 wt%, 2.58 wt% and 35.07 wt%, respectively. The layer stacking of plate anorthite is closely combined with the corundum to form a microscopic block. The rod-like mullite is interspersed in the microscopic block to form a skeleton structure. This microstructure makes the mechanical properties of the ceramic bricks superior, and the compressive strength is 138.2 MPa. The sintering process of ceramic bricks prepared by ER can be divided into four stages. Stage 1 (25 °C–200 °C) mainly involved the removal of free water and crystal water and the decomposition of part of AlO(OH) into γ-Al2O3, the corresponding kinetic mechanism is phase boundary chemical second-order reaction mechanism. Stage 2 (200 °C–400 °C) mainly involved the residual AlO(OH) decomposed into γ-Al2O3, the corresponding kinetic mechanism is phase boundary–controlled reaction and one-dimensional movement mechanism. Stage 3 (400 °C–900 °C) mainly involved the γ-Al2O3 transformed into α-Al2O3, CaCO3 and CaSO4 decompose into CaO, and CaO reacts with SiO2 and α-Al2O3 to form (Ca,Na)(Al,Si)4O8 and CaAl2Si2O8, the corresponding kinetic mechanism is random nucleation and growth mechanism. Stage 4 (900 °C–1200 °C) mainly involved the melting of (Ca,Na)(Al,Si)4O8, and the continuous formation of CaAl2Si2O8, Ca(Al, Fe)12O19 and mullite, the corresponding kinetic mechanism is Mampel power law exponential form nucleation reaction mechanism.