A kaolin bleaching method is characterized by comprising steps as follows: water is added to kaolin raw ore, a raw stock is formed and subjected to sand removal and stage treatment by a
hydrocyclone, and
slurry is prepared;
sulfuric acid is added to the
slurry, the pH (potential of
hydrogen) is adjusted to range from 2.0 to 3.0, and the
slurry is placed in a closed container with a stirring function; the
solid content of kaolin in the slurry in the closed container is measured,
sodium hydrosulfite is added, and the adding amount of
sodium hydrosulfite is 0.5%-1% of the
solid content of the kaolin; then, the mixture is stirred for 4-8 min each time and reacts for 4-8 h;
sodium hydrosulfite is added to the slurry obtained in the third step, and the adding amount of sodium hydrosulfite is 0.5%-1% of the
solid content of the kaolin; the mixture is stirred again for 4-8 min each time and reacts for 4-8 h; after a reaction ends, EDTA (
ethylene diamine tetraacetic acid) is added, the adding amount of EDTA is 0.1%-0.5% of the
solid content of the kaolin, and the mixture is stirred uniformly; filter pressing is performed, and a bleached
kaolin product is obtained. By means of the bleaching method, a remarkable deironing and whitening effect can be achieved, and the market price of the
kaolin product is greatly increased.