Abstract: Effect of autoclaved schedule for compressive strength of hematite tailing-lime-yellow sand system was studied.The suitable autoclaved schedule was that rise time, autoclave pressure, autoclave time, and decompression time were 2.1 h, 1.2 MPa, 6 h and 3.5 h, respectively, when the quality ratio of hematite tailings∶lime∶yellow sands was equal to 70∶15∶15 and forming pressure was 20 MPa.The mechanism of Effect of autoclaved schedule for compressive strength was discussed by XRD and DSC.The results show that in the hydration reaction process, hydrogarnet is firstly generated, and then CSH(I) and high-strength tobermorite under the condition of 1.2 MPa autoclaved pressure.With autoclave continuing, tobermorite is gradated into relative low-strength xonotlite.

Key words: Autoclaved schedule, Hematite tailings, Compressive strength