| abstract |
Highly transparent alumina hydrate particles are provided which have a large pore volume, have a pore diameter falling to a certain range, and which exhibit low viscosity when formed into a high-concentration dispersed sol. The general formula x M 2 O · y (NH 4) 2 O · Al 2 O 3 · z H 2 O (2 × 10 -4 ≤x ≤25 × 10 -4, 0.1 × 10 -4 ≤y ≤20 × 10 -4 , 0.6 ≤ z ≤ 2.5, M represents an alkali metal; when the alkali metal is in M 2 O format, x is its mole number per mole of Al 2 O 3 ; when ammonia is in (NH 4 ) 2 O format , y is the number of moles per mole of Al 2 O 3 ; z is the alumina hydrate particles having a composition represented by moles of hydrate (H 2 O) per mole of Al 2 O 3 , an average particle diameter of 0.02 to 0.2 μm, Alumina hydrate particles having a total pore volume of 0.5 to 1.5 ml / g, and a volume of pores having a diameter of 15 to 30 nm of 0.3 to 1.0 ml / g. |