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US 2023/0183085 A1Published application
Stable Shaped Alumina and Method for Producing Same
OwnerAndrea Brasch, Angela Siegel +2inventors
InventorsAndrea Brasch, Angela Siegel, Yanick Holzmann, Stefan Howe
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Abstract
The present invention relates to a calcined shaped alumina and to a method of preparing a calcined shaped alumina. The method comprises that the alumina in the alumina suspension is hydrothermally aged to have a specific crystallite size. This in turn produces a highly stable alumina in the form of a calcined shaped alumina particularly at temperatures of 1200° C. and above.
Claims19
A calcined shaped alumina comprising the following features a) and b):
- a) a crush strength between 30 and 70 N;
- and
- b) a monodispersed pore radius distribution with a median pore radius between 5 and 12 nm,
- wherein the calcined shaped alumina is in the form of spheroids having a sphericity of above 0.9, extrudates, tablets or mixtures thereof.
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A method to prepare a calcined shaped alumina, the method comprising the following steps:
- i) preparing an alumina suspension, the alumina suspension comprising alumina and at least water;
- ii) hydrothermally ageing the alumina suspension until the alumina in the alumina suspension has a crystallite size along the (120) axis and the (020) axis each of 70 to 110 Å to form a hydrothermally aged alumina suspension,
- iii) optionally drying the hydrothermally aged alumina suspension to obtain an alumina powder;
- iv) optionally preparing either an alumina paste from the alumina powder or an alumina dispersion from either the alumina powder or the hydrothermally aged alumina suspension;
- v) shaping the alumina powder, or the alumina paste or the alumina dispersion or the hydrothermally aged alumina suspension or mixtures thereof to form a shaped alumina;
- vi) drying the shaped alumina to form a dried shaped alumina;
- and
- vii) calcining the dried shaped alumina to form a calcined shaped alumina,
- wherein the calcined shaped alumina is in the form of spheroids having a sphericity of above 0.9, extrudates, tablets or mixtures thereof.
6 more elements
Dependencies are inferred from the claim text.