Infrared absorption spectra of the precipitated solids separated from aluminiumhydroxide solutions below the pH of minimum solubility of AI(OH)3 demonstrate the slow ageing of polymeric A1 complexes to gibbsite. On comparison with the spectra of natural gibbsites, shifts in absorption frequency during crystal growth are interpreted in terms of changes in hydrogen bonding as a consequence of dep...

Bayerite is one of the phases of aluminum hydroxide which is precipitated by the carbonation of aluminate solutions obtained from sintered nepheline syenite leaching. In this study, the conditions for the bayerite formation were predicted by thermodynamic modeling of the carbonation process and the Bromley- Zemaitis model was used for this purpose. Carbonation experiments were carried out a...

Nickel-induced morphology change of mesostructured alumina with amorphous walls to bayerite tetrahedra when treated in water, and then to γ-alumina with worm-like mesopores topologically after it was calcined at 400 °C is reported. The catalytic activity for selective CO methanation increased significantly after this treatment.

Common complexing ligands such as chloride and sulfate can significantly impact the sorption of Hg(II) to particle surfaces in aqueous environmental systems. To examine the effects of these ligands on Hg(II) sorption to mineral sorbents, macroscopic Hg(II) uptake measurements were conducted at pH 6 and [Hg](i)=0.5 mM on goethite (alpha-FeOOH), gamma-alumina (gamma-Al(2)O(3)), and bayerite (beta...

Aluminium oxyhydroxysulfates and hydroxides are known to precipitate from mining-generated acidic, neutral basic pH drainage waters that enriched in potentially toxic metal(loid)s. Their role as medium-term (1 year) sinks of Al, As, Cu Ni at values 4, 7 10 was assessed using batch experiments. X-ray diffraction analysis showed basaluminite initially formed 4 7, whereas 10, bayerite or nordstran...

Gibbsite and bayerite may be distinguished by Raman spectroscopy (Huneke et al., 1980), with the laser Raman microprobe providing a non-destructive method of analysing small quantities particularly where the habit and/or fine grain size defy other techniques (e.g. Crestin-Desjobert et al., 1987). The Raman spectra of other polymorphs of aluminium hydroxide have not been recorded. This study det...