Process for the production at a high level of productivity of aluminum trihydroxide in a high state of purity and with a median diameter of less than 4 micrometers, which is regulated as required

摘要

A process for the production of pure aluminum trihydroxide having a controlled median diameter of less than 4 microns with a unimodal distribution and a minimum deviation. The process comprises contacting, for a short time, sodium aluminate solution with a small quantity of ground aluminum trihydroxide having a specific BET surface area of at least 8 m2/g, separating the sodium aluminate solution from the solid phase comprising ground aluminum trihydroxide and aluminum trihydroxide precipitate containing impurities, then decomposing the purified sodium aluminate solution in the presence of a quantity of pure ground aluminum trihydroxide from a preceding decomposition operation to precipitate a very pure aluminum trihydroxide having the specified median diameter.