Mullite material as well as preparation method and application thereof

The invention relates to a mullite material and a preparation method and application thereof, and the method comprises the following steps: mixing fly ash, a calcium medium and water, stirring, and carrying out solid-liquid separation to obtain an intermediate product; sequentially carrying out acid treatment and solid-liquid separation on the obtained intermediate product to obtain slag; the obtained slag is sequentially subjected to alkali treatment and solid-liquid separation, and the mullite material is obtained. According to the method, the calcium-containing raw material is added to selectively react with glassy SiO2 and Al2O3 in the fly ash, so that the glassy SiO2 and Al2O3 are converted into easily removed forms and efficiently removed, and the mullite material with a high alumina-silica ratio is obtained. The method does not need additional aluminum-rich raw materials and does not need a high-temperature roasting process, so that the technological process is simplified, and the cost is reduced. Acco