Modified talc for fireproof flame-retardant coating and manufacturing method thereof

The invention relates to modified talc for a fireproof flame-retardant coating. The SBDY-1 whiteness of the product is more than or equal to 89 percent, the 5-micron fineness content of talc particles in dispersion is more than or equal to 50 percent, and the modified talc accounts for 40-60 mass percent in the fireproof flame-retardant coating. The manufacturing method of the modified talc comprises the following steps: selecting a talc raw material of which the ignition loss is in a range from 8 percent to 14 percent, the purity of talc is over 75 percent and which has a natural sheet structure, oscillating, cleaning, performing far-infrared drying, hammering, crushing, preliminarily grinding to the granularity of 325 meshes, preliminarily mixing with silane hydrolysate, blending the preliminary mixture with a polyhydroxylated compound and acid form ammonium salt with the same granularity, finely grinding to the granularity of 1250 meshes, and performing secondary adsorption modification on the mixture and the silane hydrolysate; and performing screw propulsion, uniformly stirring to pass through a square hole sieve with the granularity of 20 meshes, pressurizing, and extruding, thereby obtaining the prismatic granular product. The modified talc has high hydrophilcity and is easy to disperse in an aqueous phase; and moreover, the functions of dehydrating catalysis and foaming are integrated into a whole, and three effects such as flame retardance, smoke abatement and synergism of the fireproof flame-retardant coating are combined into a whole.