Die Bildung von kristallinem Böhmit in gemeinsam gefällten AlFe(III)-Hydroxiden unter hydrothermalen Bedingungen

Under mild hydrothermal conditions originally amorphous aluminium hydroxide coprecipitated with iron(III)ions as Al_0,5Fe_0,5(OH)₃ transforms into aluminium hydroxide crystalline phases which are not observed in products of ageing of pure aluminium hydroxide.By X-ray diffraction analysis, IR spectroscopic studies and microscopic observations it has been found that due to the presence of iron(III) hydroxide it is possible to stabilize the trihydoxide of aluminium i.e. bayerite until 130–140°C. Moreover, with increasing temperature well crystallized boehmite is obtained instead of the usually formed pseudoboehmite.Experiments revealed that the formation of crystalline boehmite does not take place as a process of pseudoboehmit crystallites growth but only as a result of bayeriteboehmite transformation.