Method for preparing high purity aluminum monohydrate and alpha alumina
AssigneeAlmatis GmbH
InventorsTobias Frueh, Marius Schustereder, Wolfram J. Lingenberg
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Abstract
The present invention concerns a method of preparing aluminum monohydrate comprising the steps of i) mixing alumina feedstock with ethylenediamine tetraacetic acid, to obtain a feedstock mixture, and ii) subjecting the feedstock mixture to a hydrothermal treatment, wherein the wherein the pH of the feedstock mixture is at least 8. The resulting aluminum monohydrate, although starting from low purity feedstocks, shows an excellent purity and can be calcined to obtain high purity alpha alumina.
Claims19
A method of preparing aluminum monohydrate comprising the steps of:
- mixing an alumina feedstock with ethylenediamine tetraacetic acid, to obtain a feedstock mixture, and
- subjecting the feedstock mixture to a hydrothermal treatment,
- wherein the pH of the feedstock mixture is at least 8,
- wherein the feedstock mixture comprises ammonia, and
- wherein the content of ammonia relative to the content of the alumina feedstock ranges from 1.25 wt % to 3.70 wt %.
A method of preparing aluminum monohydrate comprising the steps of:
- mixing an alumina feedstock with ethylenediamine tetraacetic acid, to obtain a feedstock mixture, and
- subjecting the feedstock mixture to a hydrothermal treatment,
- wherein the pH of the feedstock mixture is at least 8, wherein the feedstock mixture comprises ammonia, and wherein a weight ratio of the alumina feedstock to ammonia is from 100:1 to 10:1.
A method of preparing aluminum monohydrate comprising the steps of:
- mixing an alumina feedstock with ethylenediamine tetraacetic acid, to obtain a feedstock mixture, and
- subjecting the feedstock mixture to a hydrothermal treatment,
- wherein the pH of the feedstock mixture is at least 8, wherein the feedstock mixture further comprises ammonium hydroxide.
A method of preparing alpha alumina, the method comprising:
- mixing an alumina feedstock with ethylenediamine tetraacetic acid, to obtain a feedstock mixture, and
- subjecting the feedstock mixture to a hydrothermal treatment,
- wherein the pH of the feedstock mixture is at least 8, thereby preparing aluminum monohydrate,
- and then calcinating the aluminum monohydrate to obtain alpha alumina.
A method of preparing alpha alumina, the method comprising using ethylenediamine tetraacetic acid in a hydrothermal treatment to prepare the alpha alumina.
Dependencies are inferred from the claim text.