Environment-friendly heat-resistant precoated sand as well as preparation method and application thereof

The invention discloses environment-friendly heat-resistant precoated sand and a preparation method and application thereof.The environment-friendly heat-resistant precoated sand comprises silica sand, phenolic resin, a curing agent, a lubricating agent and iron tailings, the adding amount mass ratio of the silica sand to the phenolic resin is 96-98: 1-3, and the adding amount of the iron tailings accounts for 0.1-1.2 wt% of the silica sand; the preparation method comprises the following steps: uniformly mixing the silica sand of which the surface is sequentially coated with the phenolic resin layer and the curing agent layer with the iron tailing powder of which the particle size is less than 500 meshes, and then uniformly mixing with the lubricant. The iron tailing auxiliary agent is adopted to treat the precoated sand and can replace a fireproof coating and an iron oxide auxiliary agent so as to improve the heat resistance of the precoated sand, the cost advantage is obvious, the processes of coating and d