High-strength castable for prolonging service life of desulfuration spray gun and preparation method thereof

The invention discloses a high-strength castable for prolonging the service life of a desulfuration spray gun and a preparation method thereof. The castable is composed of following raw materials, by mass, 8-20% of andalusite, 15-25% of mullite, 20-35% of flint clay, 10-25% of spinel, 4-8% of SiC, 10-20% of a binding agent, and a water reducing agent accounting for 0.04-0.12% of the total weight the raw materials hereinabove. In the invention, the flint clay and the mullite are used as the main raw materials of the castable, the andalusite is used as an expansion agent and the spinel and fine powder of SiC are used as a composite additive in the castable. In addition, a multi-stage blending process is employed with the low-cement combination technology being applied, wherein the characters of ultra-micro powder are fully considered, so that the castable is excellent in normal temperature performances and is high in medium and high temperature strength.