Process for recovering soda and alumina values from red mud
AssigneeReynolds Metals Company
InventorKizhakke G. Hrishikesan
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Abstract
A process is disclosed for recovering the caustic and alumina values from high iron-containing Bayer red mud utilizing the so-called lime-soda-sinter process wherein a carbonaceous material such as coke is included in the sintering operation and leaching is carried out without any intermediate iron separation step.
Claims6
In the process of treating a Bayer red mud which has a Fe.sub.2 O.sub.3 to SiO.sub.2 weight ratio of at least 0.4 according to the lime-soda-sinter process wherein said mud is reacted with a source of calcium oxide in order to form a sinter and the sinter is thereafter leached in order to recover sodium aluminate, the improvement which comprises carrying out the sinter operation on a mud which has a Fe.sub.2 O.sub.3 to SiO.sub.2 weight ratio of at least 0.4 and, prior to the sinter operation, adding to said Bayer red mud a quantity of carbon in a carbon-containing material that is substantially less than the quantity of carbon required to reduce a substantial part of said Fe.sub.2 O.sub.3 to metallic iron and is at least 0.3 moles of carbon per mole of Fe.sub.2 O.sub.3 and leaching the sinter to recover caustic and alumina values, without removing iron prior to said leaching.
A recovery process for recovering available soda and alumina values from a high iron-Bayer red mud, comprising:
- A. adding from 0.33 to about 3 moles of carbon in a carbon-containing material per mole of Fe.sub.2 O.sub.3 to said high iron-Bayer red mud to form a mixture;
- B. subjecting said mixture to a conventional lime-soda-sinter operation to form a sinter;
- and
- C. without prior separation of iron from said sinter, extracting said sinter with an NaOH solution to recover said available soda and alumina values.
Dependencies are inferred from the claim text.