The thermal transformation of Gelatinous Aluminium Hydroxide

Abstract

AbstractThe thermal transformation of the gelatinous aluminium hydroxides (amorphous and pseudoboehmite) prepared from aqueous aluminium chloride solution on addition of sodium hydroxide at various pH, have been studied by X‐ray diffraction, infrared spectra and thermal analyses. As a result, it is concluded that the gelatinous aluminium hydroxides transform thermally as follows: amorphous aluminium hydroxide → amorphous alumina →γ‐alumina → θ‐alumina → α‐alumina, pseudoboehmite → γ‐alumina → θ‐alumina → α‐alumina.Further the thermal transformation of bayerite, prepared from the aqueous solution at higher pH, and of boehmite, prepared hydrothermally from gelatinous aluminium hydroxide, have been investigated in comparison with those of gelatinous aluminium hydroxide.