Abstract:
The effect of external conditions on the growth morphology of gibbsite, gamma -Al(OH)(3), grown under a range of conditions has been studied. The results show that during growth the morphology of gibbsite crystals evolves from thin, rounded hexagons and faceted lozenges into faceted plates and blocks with well-formed basal, prismatic and chamfered faces. This morphology evolution shows only a weak dependence on the growth conditions. Moreover, increasing the driving force or the caustic concentration leads to larger crystals, up to tens to a hundred pm in size. The influence of small amounts of inorganic impurities on the growth of gibbsite crystals turns out to be negligible. Different growth morphologies are obtained from potassium and cesium hydroxide solutions. This indicates that the alkali ions of the solution have a major influence on the morphology of gibbsite. The twinning behaviour is similar for gibbsite crystals grown from sodium, potassium or cesium aluminate solutions.