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US5264192A
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Method for detoxifying cyanide-containing water
Assignee: Bateman Engineering Inc
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Filing: 1992-05-21
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Granted: 1993-11-23
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Expires: 2012-05-21
Abstract
Abstract A method for treating cyanide-contaminated water in order to remove dissolved (e.g. free) cyanide (HCN and/or CN - ) therefrom. Cyanide-contaminated water is a significant problem in the gold processing industry wherein cyanide compounds are used to remove gold from ore. The remaining cyanide solution after gold extraction is treated to reduce free cyanide levels therein by combining the solution with a crystalline waste by-product of the metal galvanizing industry having the following formula: (Fe·Zn)SO 4 ·7H 2 O. This material preferably has a zinc content of about 1-14% by weight, and is added to the water in an amount equal to about 1-5 pounds per ton of ore being processed. As a result, a stable, solid, non-toxic complex is produced from the toxic free cyanide materials. This is accomplished without the generation of harmful acids, heavy metals, excessive iron levels or other undesired by-products.
Inventors
- 👤 Thomas C. Shutt
- 👤 Richard H. Eaman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:18
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/5236; C02F2101/00; C02F2101/10; C02F2101/16; C02F2101/18
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
73 words
A method for detoxifying cyanide-containing water by removing free cyanide therefrom comprising the steps of: providing a supply of water comprising free cyanide therein; combining a cyanide treatment agent with said supply of water, said cyanide treatment agent comprising (Fe·Zn)SO 4 ·7H 2 O; and allowing said cyanide treatment agent to react with said free cyanide in said supply of water in order to form a non-toxic ferrocyanide complex from said free cyanide.
Claim 2
Independent Claim
73 words
A method for detoxifying cyanide-containing water by removing free cyanide therefrom comprising the steps of: providing a supply of water comprising free cyanide therein; combining a cyanide treatment agent with said supply of water, said cyanide treatment agent comprising (Fe·Zn)SO 4 ·7H 2 O; and allowing said cyanide treatment agent to react with said free cyanide in said supply of water in order to form a non-toxic ferrocyanide complex from said free cyanide.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said cyanide treatment agent comprises about 1-14% by weight zinc.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein said cyanide treatment agent comprises about 2-6% by weight zinc.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said cyanide treatment agent comprises about 9-12% by weight zinc.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein said ferrocyanide complex comprises Zn 2 Fe(CN) 6 .
Claim 7
Dependent Claim
34 words
The method of claim 1 wherein said cyanide treatment agent is in the form of a plurality of individual crystals, each of said crystals having a size equal to about 10-30 U.S. standard mesh.
Claim 8
Dependent Claim
124 words
In a cyanide-based gold extraction process comprising the steps of: (A) providing a supply of powdered gold ore; and (B) contacting said supply of powdered gold ore with a solution comprising free cyanide therein, wherein said contacting of the powdered gold ore with the solution results in extraction of gold from said powdered gold ore and leaves a residual cyanide containing solution, a method for detoxifying the residual cyanide containing solution in order to remove free cyanide therefrom wherein the improvement comprises: combining said residual cyanide containing solution with a cyanide treatment agent comprising (Fe·Zn)SO 4 ·7H 2 O; and allowing said cyanide treatment agent to react with free cyanide in the residual cyanide containing solution in order to form a non-toxic ferrocyanide complex.
Claim 9
Dependent Claim
124 words
In a cyanide-based gold extraction process comprising the steps of: (A) providing a supply of powdered gold ore; and (B) contacting said supply of powdered gold ore with a solution comprising free cyanide therein, wherein said contacting of the powdered gold ore with the solution results in extraction of gold from said powdered gold ore and leaves a residual cyanide containing solution, a method for detoxifying the residual cyanide containing solution in order to remove free cyanide therefrom wherein the improvement comprises: combining said residual cyanide containing solution with a cyanide treatment agent comprising (Fe·Zn)SO 4 ·7H 2 O; and allowing said cyanide treatment agent to react with free cyanide in the residual cyanide containing solution in order to form a non-toxic ferrocyanide complex.
Claim 10
Dependent Claim
16 words
The method of claim 7 wherein said cyanide treatment agent comprises about 1-14% by weight zinc.
Claim 11
Dependent Claim
16 words
The method of claim 7 wherein said cyanide treatment agent comprises about 2-6% by weight zinc.
Claim 12
Dependent Claim
15 words
The method of claim 7 wherein said ferrocyanide complex comprises Zn 2 Fe(CN) 6 .
Claim 13
Dependent Claim
34 words
The method of claim 7 wherein said cyanide treatment agent is in the form of a plurality of individual crystals, each of said crystals having a size equal to about 10-30 U.S. standard mesh.
Claim 14
Dependent Claim
54 words
The method of claim 7 wherein said combining of said residual cyanide containing solution with said cyanide treatment agent comprises the step of adding said cyanide treatment agent to said residual cyanide containing solution in an amount equal to about 1-5 pounds of said cyanide treatment agent per ton of said powdered gold ore.
Claim 15
Dependent Claim
51 words
The method of claim 7 wherein said combining of said residual cyanide containing solution with said cyanide treatment agent comprises the step of adding said cyanide treatment agent to said solution in an amount equal to about 2-3 pounds of said cyanide treatment agent per ton of said powdered gold ore.
Claim 16
Dependent Claim
126 words
In a cyanide-based gold extraction process comprising the steps of: (A) providing a supply of individual portions of rock containing gold therein; (B) arranging said portions of rock in a pile; and (C) applying a solution comprising free cyanide therein to said pile, with said solution extracting gold as it passes downwardly through said portions of rock and leaving a residual cyanide containing solution a method for detoxifying the residual cyanide containing solution in order to remove free cyanide therefrom wherein the improvement comprises: combining said residual cyanide containing solution with a cyanide treatment agent comprising (Fe·Zn)SO 4 ·7H 2 O; and allowing said cyanide treatment agent to react with free cyanide in the residual cyanide containing solution in order to form a non-toxic ferrocyanide complex.
Claim 17
Dependent Claim
126 words
In a cyanide-based gold extraction process comprising the steps of: (A) providing a supply of individual portions of rock containing gold therein; (B) arranging said portions of rock in a pile; and (C) applying a solution comprising free cyanide therein to said pile, with said solution extracting gold as it passes downwardly through said portions of rock and leaving a residual cyanide containing solution a method for detoxifying the residual cyanide containing solution in order to remove free cyanide therefrom wherein the improvement comprises: combining said residual cyanide containing solution with a cyanide treatment agent comprising (Fe·Zn)SO 4 ·7H 2 O; and allowing said cyanide treatment agent to react with free cyanide in the residual cyanide containing solution in order to form a non-toxic ferrocyanide complex.
Claim 18
Dependent Claim
16 words
The method of claim 14 wherein said cyanide treatment agent comprises about 1-14% by weight zinc.
Claim 19
Dependent Claim
16 words
The method of claim 14 wherein said cyanide treatment agent comprises about 9-12% by weight zinc.
Claim 20
Dependent Claim
15 words
The method of claim 14 wherein said ferrocyanide complex comprises Zn 2 Fe(CN) 6 .
Claim 21
Dependent Claim
33 words
The method of claim 14 wherein cyanide treatment agent is in the form of a plurality of individual crystals, each of said crystals having a size equal to about 10-30 U.S. standard mesh.
Claim 22
Dependent Claim
50 words
The method of claim 14 wherein said combining of said residual cyanide containing solution with the cyanide treatment agent comprises the step of adding said cyanide treatment agent to said solution in an amount equal to about 1-5 pounds of cyanide treatment agent per ton of said portions of rock.
Claim 23
Dependent Claim
53 words
The method of claim 16 wherein said combining of said residual cyanide containing solution with the cyanide treatment agent comprises the step of adding said cyanide treatment agent to said residual cyanide containing solution in an amount equal to about 2-3 pounds of cyanide treatment agent per ton of said portions of rock.
References Cited (Backward Citations)
No citation records indexed.
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