Preparation of aluminate cement by using the secondary aluminum ash as a partial substitute for alumina

In response to the scarcity and high cost of bauxite, a raw material for aluminate cement, this study explored the feasibility of preparing aluminum cement by using secondary aluminum ash as a substitute for bauxite. The calcination experiment results showed that the optimal preparation conditions were an Al₂O₃ content of 60%, a calcination temperature of 1 350 ℃, and an insulation time of 1 h. The aluminate cement samples were mixed with standard sand for natural curing. SEM and EDS analysis were conducted on the hydrated aluminate cement samples at 3 and 28 d, respectively. Under these conditions, the mineral phases obtained in the aluminate cement clinker were dicalcium aluminate, gehlenite, and a small amount of tricalcium aluminate. The compressive strength of the aluminate cement hydrated for 28 d reached 85.5 MPa, and the flexural strength 11.5 MPa, proving that the secondary alumina ash can be used as a partial substitute for bauxite to prepare aluminate cement.