Zinc removal from aluminate solutions
US4282191A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1980 |
| Grant date | Aug 4, 1981 |
| Priority date | — |
| Expiry date | Jul 25, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01G9/08
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a process of the preparation of alumina from an alumina value containing material wherein a caustic sodium aluminate process liquor is subjected to a treatment to reduce the level of zinc impurity by the addition of ZnS seed in the presence of sulfide ion, the improvement comprising: PA0 (I) forming the zinc sulfide seed a by process comprising the steps of: PA1 (A) dissolving ZnO in NaOH to produce a caustic Na.sub.2 ZnO.sub.2 solution; and PA1 (B) reacting the solution of (A) with Na.sub.2 S to form ZnS, the Na.sub.2 S being present at a level sufficient to provide a concentration of Na.sub.2 S of at least about 0.150 g/l of Na.sub.2 S when the product of this step is added to the process liquor; PA0 (II) adding the product of step (B) to the process liquor to precipitate as ZnS, zinc contained as sodium zincate in the process liquor; and PA0 (III) filtering the process liquor to yield an NaAlO.sub.2 liquor containing less than 15 mg/l and preferably below about 10 mg/l zinc as ZnO.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.