Patent US1924244A successfully refreshed from Google Patents.
Patent US4250030A successfully refreshed from Google Patents.
US4250030A
Expired / Lapsed
US
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Process for the removal of cyanides from effluent
Assignee: Teck Metals Ltd
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Filing: 1980-01-21
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Granted: 1981-02-10
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Expires: 2000-01-21
Abstract
Abstract A method is disclosed for removal of free and complex cyanides from water-containing industrial effluents and wastes by treatment with insoluble solid iron sulfides at a pH in the range of about 7.0 to 8.5. The insoluble solid iron sulfides can be chemically prepared prior to treatment or prepared in situ, usually of a particle size smaller than about 5μ, or supplied in the form of naturally occurring iron sulfides such as pyrrhotite or pyrite having a particle size smaller than about 300μ, preferably smaller than about 150μ. The weight ratio of iron sulfide to total cyanide in the effluent is greater than 2:1, preferably greater than about 5:1 for prepared iron sulfides and greater than about 100:1 for mineral sulfides. The presence of a reducing agent such as ferrous ions or sodium sulfite to maintain a non-oxidizing environment during treatment enhances removal of cyanide.
Inventors
- 👤 Wouterus J. M. Kuit
- 👤 Alan R. Babcock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:47
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/70; C02F1/28; C02F1/281; C02F2101/00; C02F2101/10; C02F2101/16; C02F2101/18; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903; Y10S210/904
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
110 words
A method for the removal of dissolved free and complex cyanides from water-containing effluent which comprises controlling the pH of said effluent in a range of about 7.0 to 8.5 and contacting said effluent with an effective amount of an insoluble solid iron sulfide chosen from at least one of ferrous sulfide and ferric sulfide having particle sizes smaller than about 300μ for a period of time of at least about 5 minutes to remove said dissolved free and complex cyanides to a desired level, said effective amount being sufficient to give a weight ratio of said iron sulfide to total cyanide in said effluent of greater than about 2:1.
Claim 2
Independent Claim
110 words
A method for the removal of dissolved free and complex cyanides from water-containing effluent which comprises controlling the pH of said effluent in a range of about 7.0 to 8.5 and contacting said effluent with an effective amount of an insoluble solid iron sulfide chosen from at least one of ferrous sulfide and ferric sulfide having particle sizes smaller than about 300μ for a period of time of at least about 5 minutes to remove said dissolved free and complex cyanides to a desired level, said effective amount being sufficient to give a weight ratio of said iron sulfide to total cyanide in said effluent of greater than about 2:1.
Claim 3
Dependent Claim
31 words
A method as claimed in claim 1, wherein the effluent contains cyanides of at least one of cyanide ions, complex cyanide ions of iron, copper, nickel and zinc, or mixtures thereof.
Claim 4
Dependent Claim
34 words
A method as claimed in claim 1, wherein said iron sulfide is prepared prior to treatment of effluent or in situ during treatment of effluent and has a particle size smaller than about 5μ.
Claim 5
Dependent Claim
21 words
A method as claimed in claim 3, wherein said weight ratio is in the range of about 5:1 to about 20:1.
Claim 6
Dependent Claim
29 words
A method as claimed in claim 4, wherein the effluent is contacted with the iron sulfide in a single stage, or in two or more co-current or counter-current stages.
Claim 7
Dependent Claim
42 words
A method as claimed in claim 3, 4 or 5, wherein the effluent and iron sulfide are agitated to ensure intimate contact between said effluent and iron sulfide particles and said pH is controlled in a range of about 7 to 8.
Claim 8
Dependent Claim
35 words
A method as claimed in claim 6, wherein iron sulfide is separated from effluent after contacting with said iron sulfide and at least a portion of the separated iron sulfide is returned to said treatment.
Claim 9
Dependent Claim
31 words
A method as claimed in claim 3, 4 or 5, wherein said contacting is carried out for a period of time in the range of about 15 to about 180 minutes.
Claim 10
Dependent Claim
28 words
A method as claimed in claim 3, 4 or 5, wherein said contacting is carried out for a time in the range of about 15 to 60 minutes.
Claim 11
Dependent Claim
35 words
A method as claimed in claim 1, wherein the effluent is contacted with a particulate material chosen from concentrate and tailings, said material containing at least one mineral iron sulfide chosen from pyrrhotite and pyrite.
Claim 12
Dependent Claim
17 words
A method as claimed in claim 10, wherein said particulate material has particle size smaller than 150μ.
Claim 13
Dependent Claim
16 words
A method as claimed in claim 11, wherein said weight ratio is at least about 100:1.
Claim 14
Dependent Claim
26 words
A method as claimed in claim 1, wherein said contacting is carried out for a time in the range of about 30 minutes to 10 hours.
Claim 15
Dependent Claim
42 words
A method as claimed in claim 11, 12 or 13, wherein the effluent and iron sulfide are agitated to ensure intimate contact between said effluent and iron sulfide particles and said pH is controlled in a range of about 7 to 8.
Claim 16
Dependent Claim
30 words
A method as claimed in claim 1, wherein effluent is percolated at a pH in the range of about 7 to 8 through a particulate body containing mineral iron sulfide.
Claim 17
Dependent Claim
50 words
A method as claimed in claim 15, wherein said effluent is percolated through a particulate body of material chosen from concentrate and tailings containing at least one iron sulfide chosen from pyrrhotite and pyrite, and wherein the contact time of effluent with said body is at least about 30 minutes.
Claim 18
Dependent Claim
21 words
A method as claimed in claim 16, wherein said contact time is in the range of about one to 24 hours.
Claim 19
Dependent Claim
22 words
A method as claimed in claim 17, wherein said particulate body has particle sizes in the range of about 44 to 300μ.
Claim 20
Dependent Claim
25 words
A method as claimed in claim 15, 16 or 17, wherein said particulate body has particle sizes in the range of about 44 to 150μ.
Claim 21
Dependent Claim
19 words
A method as claimed in claim 15, 16 or 17, wherein said weight ratio is at least about 100:1.
Claim 22
Dependent Claim
27 words
A method as claimed in claim 1 or 2, wherein the effluent contains ferro-cyanide and wherein the effluent is treated with an excess of free ferrous ions.
Claim 23
Dependent Claim
27 words
A method as claimed in claim 1 or 2, wherein the iron sulfide is ferrous sulfide and the effluent is treated in the presence of sodium sulfite.
References Cited (Backward Citations)
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US2845330A
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CA978677A
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US3736239A
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JPS4969544A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |