Method for preparing non-autoclaved hydrophobic fiber reinforced calcium silicate board from fly ash

The invention provides a method for preparing a non-autoclaved hydrophobic fiber reinforced calcium silicate board from fly ash, which comprises the following steps of: (1) mixing fly ash, calcium oxide, a dilute sodium hydroxide solution and a structure regulator according to a certain ratio in a closed reactor for one-step dynamic hydrothermal reaction, and after the reaction, filtering and washing slurry to obtain hydrated wet calcium silicate slag; and (2) well mixing the hydrated wetcalcium silicate slag obtained in the step (1) with cement, fibers and an organosilicon waterproofing agent according to a certain mass ratio, carrying out compression molding under the pressure of 20-60MPa, demolding a molded blank, and drying to obtain a non-autoclaved hydrophobic fiber reinforced calcium silicate board. Fly ash is used as a raw material, and the raw material belongs to bulk industrial solid waste and is cheap and easy to obtain. An autoclaved curing process is not needed, the equipment investment is low, t