Aluminium hydroxide gel
OwnerGerhard Kudermann, Jurgen Schubertinventors
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Abstract
The invention relates to a method for producing a stable aluminium hydroxide gel on the basis of the sodium aluminate lye which is obtained during the production of Al2O3 according to the BAYER method. The caustic mol ratio (Na2Ofree/Al2O3) of the lye containing aluminate is adjusted to smaller than 1.6. The lye is treated with carboxylic acid anhydride, whereby the aluminium hydroxide gel is precipitated at a temperature of below approximately 40° C., whereby the pH value ranges from 8 to 12. The precipitation product and the lye are separated from one another. The precipitation product is washed and dried, whereby the amorphous structure is obtained.
Claims10
A method for producing an aluminium hydroxide gel, in which the aluminate lye obtained from Al2O3 production according to the BAYER method is treated with carboxylic acid anhydride with precipitation of the aluminium hydroxide gel, wherein the caustic mol ratio (Na2Ofree/Al2O3) of the lye containing the aluminate is adjusted to less than 1.6, precipitation is carried out at a temperature of under approximately 40° C. and at a pH value of 8 to 12, precipitate and lye are separated from one another, and the precipitate is washed and dried while preserving the amorphous structure.
Dependencies are inferred from the claim text.