Castable for aluminum alloy casting launder as well as preparation method and application of castable

The invention relates to the technical field of refractory materials, and discloses a castable for an aluminum alloy casting launder as well as a preparation method and application of the castable. The castable for the aluminum alloy casting launder comprises a main material and water, the main material comprises the following components in percentage by mass: 45-53% of modified fused quartz with different granularities, 26-32% of ferrochrome slag with different granularities, 2-4% of corundum micro powder, 1-3% of barite micro powder, 1-3% of fluorite micro powder, 2-4% of forsterite micro powder, 2-4% of fly ash, 6-10% of aluminate cement and 1% of a polycarboxylate superplasticizer; and water accounts for 4-6% of the mass of the main material. The surface of the fused quartz is modified, so that the wettability and wrapping property of the fused quartz and powder water slurry can be improved, the material uniformity of the castable during stirring and forming can be improved, and the strength of the castab