Method for removing organic substances from caustic aluminate liquors
AssigneeVereinigte Aluminium-Werke Atkiengesellschaft
InventorsNeil Brown, Gerhard Kudermann, Manfred Fuchs
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Abstract
The present invention is directed to a method for removing organic substances from aluminate liquors of the Bayer process. The method comprises the steps of contacting the liquor with an oxygen containing gas under elevated pressure in the presence of metallic ions acting as a catalyst to oxidize the organic substances, precipitating the metallic ions jointly with aluminum hydroxide, separating the precipitate from the oxidized liquor and recycling the precipitated aluminum hydroxide containing the metallic ions into the oxidation step as a catalyst carrier.
Claims15
A process for removing organic carbon substances from caustic aluminate liquors of the Bayer process comprising the steps of:
- contacting said liquor containing said carbon substances with at least enough molecular oxygen-containing gas to oxidize said organic carbon substances;
- oxidizing said liquor in the presence of copper ions until a molar ratio of Na.sub.2 O to Al.sub.2 O.sub.3 of no more than 1.0 is achieved;
- converting more than 85% of said organic carbon substances to sodium carbonate;
- precipitating said copper ions jointly with bohemite by the addition of aluminum hydroxide;
- separating said precipitate from the oxidized liquor by filtration;
- and
- recycling the precipitated aluminum hydroxide-containing copper ions to the oxidation step.
A process for decontaminating Bayer process liquors which comprises
- contacting a Bayer process liquor containing carbon contaminants with an oxygen containing gas,
- conducting said contacting step at a predetermined temperature and at a predetermined pressure and in the presence of copper ions,
- continuing said contacting step until the molar ratio of Na.sub.2 O to Al.sub.2 O.sub.3 is at or below 1.0,
- adding aluminum hydroxide to said liquor to form a precipitate,
- separating said precipitate from the oxidized liquor and
- recycling the precipitate to the contacting step,
- whereby more than 85% of said organic contaminants are converted to sodium carbonate and remain in said liquor.
Dependencies are inferred from the claim text.