PURPOSE: To provide molded articles which consist essentially of gamma Al2O3 and have a single phase composition and is highly reactive by using ultrafine crystalline gibbsite particles of a single morphological structure and specifying a calcining condition by the calcination of gibbsite to produce the aluminum oxides.
CONSTITUTION: The partially crystalline, transitional aluminum oxide contains 5-fold coordinated aluminum oxide in addition to 4-fold and 6-fold coordinated aluminum oxide with respect to the oxygen of the partially crystalline solid and the content of the 5-fold coordinated aluminum oxide is more than 50% of the content of the 4-fold coordinated aluminum oxide. The ultrafine crystalline gibbsite particles of a single morphological structure (pseudo hexagonal pellet form, needle form and polygonal form) are impact-calcined in a reaction zone at 350-750°C in a particle mean resident time of 0.01-10 sec to produce the aluminum oxides. The obtained aluminum oxide is used for producing a ceramic material or the like, succeedingly rehydrated and calcined to obtain the high reactive molded articles which consist essentially of gamma Al2O3 and are used for production of an adsorbing agent or the like.
SCHMIDT HUBERTUS DR (DE)
FEIGE REINHARD (DE)
BOLLMANN ULRICH DR (DE)
LANGE RUEDIGER DR (DE)
ENGELS SIEGFRIED PROF (DE)
LEUNA WERKE AG (DE)