ALUMINA, ALUMINA SLURRY, ALUMINA FILM, LAMINATE SEPARATOR, NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND MANUFACTURING METHOD THEREOF

Disclosed is alumina having a water desorption index H (=(V-V)÷V) of 0.15 or less in a water adsorption/desorption isotherm at 25° C., where Vrepresents a water adsorption amount [mg/g] per 1 g of alumina in the desorption isotherm at a relative water vapor pressure of 0.5, Vrepresents a water adsorption amount [mg/g] per 1 g of alumina in the adsorption isotherm at a relative water vapor pressure of 0.5, and Vrepresents a water adsorption amount [mg/g] per 1 g of alumina in the adsorption isotherm at a relative water vapor pressure of 0.9.