Method for the production of stable binder-free high-purity moldings composed of metal oxides and their use

摘要

Stable high strength porous metal oxide articles suitable, for example, for use as catalyst supports, are prepared by predisposing fine metal oxide particles in water followed by fine dispersion under high shear, and subjecting the dispersion to a change in pH to coagulate the metal oxide particles and form a moldable viscoelastic composition. The moldings are substantially free of impurity atoms.

主权项

1. A porous metal oxide molding, prepared by a process comprising:
a) finely dispersing in water particles of at least one pyrogenic metal oxide selected from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, and zirconium dioxide to form an aqueous dispersion containing at least 5 weight percent of metal oxide based on the weight of the aqueous dispersion; b) increasing the pH of the aqueous dispersion to form a viscoelastic solid; c) shaping the viscoelastic solid to a green body molding; d) drying the green body molding at a temperature less than a calcination temperature; and e) optionally calcining the green body molding at a calcination temperature of at least 500° C. to form a calcined molding,wherein the aqueous dispersion is free of organic solvents and also free of organic and inorganic binders, the green body molding is dimensionally stable with a strength greater than 2 N/mm2, and the green body molding contains less than 50 ppm by weight of carbon.