CA1165474A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Cyanide removal from aqueous streams
Assignee: Vale Canada Ltd
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Filing: 1982-01-27
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Granted: 1984-04-10
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Expires: 2002-01-27
Abstract
Abstract Abstract of the Invention The cyanide content of waste waters containing the same is removed by treatment with sulfur dioxide or an alkali ox alkaline earth metal sulfite or bisulfite in the presence of excess oxygen and a metal catalyst which is preferably copper.
Inventors
- 👤 Gyula J. Borbely
- 👤 Eric A. Devuyst
- 👤 Victor A. Ettel
- 👤 Konstantin J. Schitka
- 👤 Marcel A. Mosoiu
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-02 20:22
CPC Classifications
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Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
38 words
A process for treating cyanide contained in an aqueous effluent comprising subjecting said effluent to the action of sulfur dioxide and oxygen in the presence of dissolved copper whereby said cyanide is converted to environmentally less toxic material.
Claim 2
Dependent Claim
38 words
A process for treating cyanide contained in an aqueous effluent comprising subjecting said effluent to the action of sulfur dioxide and oxygen in the presence of dissolved copper whereby said cyanide is converted to environmentally less toxic material.
Claim 3
Dependent Claim
28 words
A process according to claim 1 wherein the pH of said effluent is maintained at a selected value within the range of from about 5 to about 11.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein the sulfur dioxide is introduced to the effluent in the gaseous phase.
Claim 5
Dependent Claim
28 words
The process of claim 1 wherein the oxygen is introduced to the effluent by exposing the effluent to air by surface ex-posure, agitation, sparging or any combination thereof.
Claim 6
Dependent Claim
26 words
The process of claim 3 wherein the sulfur dioxide and oxygen are introduced to the effluent simultaneously as a sparging gas comprising sulfur dioxide and air.
Claim 7
Dependent Claim
26 words
The process of claim 1 wherein the sulfur dioxide is introduced to the effluent as a sulfite or bisulfite of an alkali or alkaline earth metal.
Claim 8
Dependent Claim
23 words
The process of claim 6 wherein the sulfite or bisulfite has a cation selected from the group consisting of sodium, potassium and calcium.
Claim 9
Dependent Claim
20 words
The process of claim 5 wherein the sparging gas is from about 0.1% to about 6% sulfur dioxide by volume.
Claim 10
Dependent Claim
31 words
The method of claim 6 wherein the sulfur dioxide is first introduced to said effluent, and the oxygen is subsequently introduced thereto by surface exposure, agitation, sparging or any combination thereof.
Claim 11
Dependent Claim
40 words
The process of claim 1, 4 or 6 wherein the pH of the effluent during the process is controlled to maintain a selected minimum pH by the controlled addition during the process of an alkali or alkaline earth metal base.
Claim 12
Dependent Claim
119 words
The process of claim 1, 4 or 6 wherein the pH of the effluent during the process is controlled to maintain a minimum pH selected to provide an economically acceptable compromise, having regard to the initial pH of said effluent, between the rate at which the action of the sulfur dioxide and oxygen in the pre-sence of dissolved copper converts said cyanide, and the cost of reagents for neutralizing the acid forming constituents brought into solution in said effluent during the process, whereby when said selected pH is below 6.5 limestone may be used as the pH control agent, and when said selected pH is above 5 lime or caustic soda may be used as the pH control agent.
Claim 13
Dependent Claim
33 words
The process of claim 1 wherein thiocyanate is present in said effluent, and the process is carried out in the presence of dissolved nickel, cobalt or manganese to catalize removal of such thiocyanate.
Claim 14
Dependent Claim
46 words
The process of claim 1 wherein subsequently to the conversion of said cyanide, the pH of said effluent is raised to about pH 10 to permit additional recovery of any metal values in the form of their insoluble hydroxides prior to the discarding of the effluent.
References Cited (Backward Citations)
No citation records indexed.
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