| 摘要 |
Process for obtaining aluminium trihydroxide having a mean diameter controlled on demand, lower than 4 microns, of unimodal distribution and low dispersion, comprising the hot decomposition of a sodium aluminate supersaturated solution in the presence of a primer consisting of aluminium trihydroxide, and the separation of the resultant solid and liquid phases and the recovery of the solid phase comprised of the precipitated aluminium trihydroxide, said process being characterized in that, in a first step, the aluminium trihydroxide is subjected to a crushing up to the obtention of crushed aluminium trihydroxide having a specific surface BET at least equal to 8 m<2> per gram and, in a second step, the crushed aluminium trihydroxide is contacted with the totality of a hot solution of sodium aluminate to be decomposed in a quantity such that the total surface of trihydroxide introduced in a crushed form is at least 100 m<2> per liter of the oversaturated sodium aluminate solution, and the decomposition of said solution is carried out by stirring the suspension formed up to the obtention of a weighted ratio of dissolved Al203/caustic Na20 not exceeding 0.7. |
