Composite castable for organic solid waste pyrolysis carbonization furnace and preparation method of composite castable

The invention relates to a composite castable for an organic solid waste pyrolysis carbonization furnace and a preparation method of the composite castable. The castable comprises the following raw materials in percentage by mass: 30-45% of corundum particles, 20-40% of silicon carbide micro powder, 10-15% of calcined alumina micro powder, 6-9% of magnesium aluminate spinel fine powder, 3-5% of micro silicon powder, 2-5% of pure calcium aluminate cement, 1-2% of sodium tripolyphosphate, 0.5-1% of a special additive and 4-10% of water, totaling 100%, wherein the special additive is a pore forming agent and a water reducing agent. According to the optimized gradation design theory, the components of the matrix alloy are self-designed, a proper amount of elements are selected, the matrix alloy has a high-temperature-resistant hard phase after heat treatment, the matrix hardness of the matrix alloy at high temperature is guaranteed, meanwhile, a silicon carbide reinforced phase is added, the high-temperature-resi