Abstract: The autoclaved aerated concrete(AAC) was prepared with iron ore tailings(IOTs) from Nanqi Iron Mine of Shanxi Lingqiu County as siliceous materials, cement and lime as calcium materials.The formulations of AAC were optimized by the orthogonal tests, and the products prepared are analyzed from its mineral composition and microstructure with XRD and SEM.The results showed that under the optimal formulations of the mass fractions of iron tailings, cement, lime and gypsum at 61%, 10%, 23% and 6% respectively, the mass ratio of aluminum powder to 4 kinds of raw materials at 0.55 ‰, and the water to materials ratio at 0.57%, the autoclaved aerated concrete with the compressive strength and the bulk density of 4.83 MPa and 596 kg/m3 was produced, which met the requirement of A3.5 and B06 level qualified product.The major phases in the AAC product are tobermorite, CSH gels, and also some gypsum and residual quartz from tailings.

Key words: Iron ore tailings, Autoclaved aerated concrete, Compressive strength, Tobermorite