Patent US4414115A successfully refreshed from Google Patents.
US4414115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of copper and zinc species from Bayer process liquor by filtration
Assignee: Alcoa Corp
•
Filing: 1981-12-21
•
Granted: 1983-11-08
•
Expires: 2001-12-21
Abstract
Abstract A Bayer process solution is filtered through a bed of particles of a granular substance containing Fe2O3 to remove copper and zinc species from the solution. The particles preferably have an Fe2O3 content of about 40 to 100% by weight. For more effective removal of zinc, the particles are coated with a metal sulfide, preferably zinc sulfide.
Inventors
- 👤 Paul J. The
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:37
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/46; C01F7/47; C02; C02F; C02F1/00; C02F1/28; C02F1/281; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
102 words
A process for decreasing the level of copper or zinc impurities in an alkali metal aluminate solution without increasing the sulfide content of the solution, said process comprising providing a filter bed comprising granular particles of a substance containing about 40 to 100% Fe 2 O 3 by weight, said particles having an average particle size of about 100 to 400 μm, coating said particles with zinc sulfide prior to filtering, by passing a zinc sulfide solution through the bed and then washing in order to avoid sulfide contamination of the aluminate solution, and filtering the aluminate solution through the filter bed.
Claim 2
Dependent Claim
102 words
A process for decreasing the level of copper or zinc impurities in an alkali metal aluminate solution without increasing the sulfide content of the solution, said process comprising providing a filter bed comprising granular particles of a substance containing about 40 to 100% Fe 2 O 3 by weight, said particles having an average particle size of about 100 to 400 μm, coating said particles with zinc sulfide prior to filtering, by passing a zinc sulfide solution through the bed and then washing in order to avoid sulfide contamination of the aluminate solution, and filtering the aluminate solution through the filter bed.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein the bed has a height of at least 38 cm.
Claim 4
Dependent Claim
37 words
The process of claim 1 further comprising the step of rejuvenating the bed by washing with a dilute aqueous solution of an inorganic acid, thereby to remove copper and zinc impurities from granular particles in the bed.
Claim 5
Dependent Claim
16 words
The process of claim 3 wherein said acid comprises HCl or H 2 SO 4 .
Claim 6
Dependent Claim
96 words
A filter medium for decreasing the level of copper or zinc impurities in an alkali metal aluminate solution without increasing the sulfide content of the solution, said filter medium comprising a bed of particles of a granular substance containing about 40 to 100 wt% Fe 2 O 3 , said particles having an average particle size of about 100 to 400 μm, and a zinc sulfide coating on said particles, said coating being formed by passing a zinc sulfide solution through the bed and then washing in order to avoid sulfide contamination of the aluminate solution.
Claim 7
Dependent Claim
96 words
A filter medium for decreasing the level of copper or zinc impurities in an alkali metal aluminate solution without increasing the sulfide content of the solution, said filter medium comprising a bed of particles of a granular substance containing about 40 to 100 wt% Fe 2 O 3 , said particles having an average particle size of about 100 to 400 μm, and a zinc sulfide coating on said particles, said coating being formed by passing a zinc sulfide solution through the bed and then washing in order to avoid sulfide contamination of the aluminate solution.
Claim 8
Dependent Claim
18 words
The filter medium of claim 5 wherein said particles contain about 56.4 wt% Fe 2 O 3 .
References Cited (Backward Citations)
FR2094528A5
Cited
JPS501560A
Cited
JPS5193548A
Cited
US3989623A
Cited
US4094777A
Cited
US4280925A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-07 | 1987-05-09 | 1987-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-07 | 1991-05-09 | 1991-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-07 | 1995-05-09 | 1995-11-08 | $7700.00 | Window Closed / Lapsed |