MANUFACTURE METHOD OF FLAKE ALUMINUM OXIDE

A method for manufacturing flake-like aluminum oxide is provided to suppress the formation of multi-crystal particles and twin-crystal particles, have a simple manufacture process, and improve production yield. A method for manufacturing flake-like aluminum oxide includes the steps of: (1) grinding an alumina hydrate or aluminum salt as a starting material, sorting out particles having a particle size of 5-50 micron, and pre-treating the starting material; (2) heating the pre-treated starting material to prepare transitional alumina; (3) selecting one or two or more, as a molten salt, selected from calcium carbonate, sodium chloride, potassium carbonate, potassium sulfate, and sodium sulfate, selecting one or two or more, as an additive, selected from LiF2, AlF3, NaF, P2(SO4)3, NaPF6, and K2TiF6, mixing the molten salt with the additive, and dispersing and grinding the mixture in the transitional alumina; (4) heating the dispersed and ground mixture in an electric furnace to melt-synthesize flake-like aluminum oxide; (5) precipitating the molten salt and additive from the synthesized aluminum oxide; and (6) removing foreign substances such as the residual additive adhered to the surfaces of the recovered flake-like aluminum oxide crystal particles. Further, the alumina hydrate is Al(OH)3, and the aluminum salt is one selected from Al2(SO4)3.4-18H2O, Al(NO3)3.9H2O or Al(CHOO)3OH.