反应详情

375.13 g (1 mol) of aluminum nitrate hydrate [Al(NO3)3·9H2O], manufactured by Wako Pure Chemical Industries Ltd., guaranteed reagent] was dissolved in pure water, giving a total volume of 1000 cm3, to obtain 1155 g of an aluminum nitrate aqueous solution having a pH of 2.1. Of this solution, to 250 cm3 of the aluminum nitrate aqueous solution was added 7.08 g of the seed crystal slurry obtained above (containing 1.42 g of α-alumina), then, 40 g of 25% ammonia water (manufactured by Wako Pure Chemical Industries Ltd., guaranteed reagent) was added at a feeding rate of 2 g/minute by using a micro rotary pump while stirring at 25° C., to obtain a slurry of pH 4 containing a hydrolysate of aluminum nitrate. This slurry was maintained at 25° C. for 24 hours, then, water was evaporated from the slurry by using a pressure-reduced drier, to obtain a dry powder. This powder contained a hydrolysate and 10 wt % of a seed crystal (α-alumina) in terms of Al2O3. This powder was ground by using a mortar, then, charged into an alumina crucible. The alumina crucible was placed in a box-type electric furnace. The powder was heated up to 950° C. at a rate of 300° C./h in air, and calcined at 950° C. for 3 hours, to obtain an α-alumina particulate. The properties of this α-alumina particulate are shown in Table 1. The photograph of the α-alumina particulate is shown in FIG. 1

1. customgiving a total volume of 1000 cm3