[aloh3]

Do I have to autoclave it? Can anyone send me a detailed procedure? Thanks.

[Intanjir]

You can produce the hydroxide by precipitating a dissolved form of aluminium.
Unfortunately, Al2O3 is quite insoluble in neutral water. With enough heat and pressure it could eventually be made to dissolve but the pressure is probably much too large to be feasible.
Both acid and base can help. Base will give you too much trouble, so instead I suggest try dissolving it in HCl solution and then neutralizing it.