Patent US4042502A successfully refreshed from Google Patents.
US4042502A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detoxification of cyanides and cyanide-containing solutions
Assignee: Jenapharm GmbH and Co KG
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Filing: 1975-03-21
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Granted: 1977-08-16
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Expires: 1995-03-21
Abstract
Abstract The method comprises preheating a cyanide solution to be detoxified by passing the cyanide solution through a heat exchanger and initiating a detoxifying hydrolysis of the cyanide solution by subjecting the cyanide solution to a temperature shock raising the temperature of the cyanide solution to between about 200° and 250° C and passing the cyanide solution through a tubular reactor at a pressure of between about 40 and 140 atm.
Inventors
- 👤 Joachim Schmidt
- 👤 Wolfgang Bamberg
- 👤 Hartmut Grunert
- 👤 Erhard Schorm
- 👤 Christian Weigelt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:57
CPC Classifications
A; A62; A62D; A62D3/00; A62D3/30; A62D3/35; C; C02; C02F; C02F1/00; C02F1/02; C02F1/025; A62D2101/00; A62D2101/40; A62D2101/45; C02F2101/00; C02F2101/10; C02F2101/16; C02F2101/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
163 words
A continuous process of detoxifying aqueous cyanide solutions comprising the steps of, starting the process cycle by heating a counterflow heat exchanger, then, in successive steps, passing the cyanide solution through a first flow path of said heat exchanger in order to preheat the solution, then, after passing the solution out of the heat exchanger, raising its temperature to a peak of about 200° to 250° C so as to effect a detoxifying hydrolysis of the solution, the solution being heated in said preheating step to more than half of the temperature reached as said peak temperature, and thereafter passing the detoxified solution through a second flow path of the heat exchanger in heat exchange contact with fresh cyanide solution passed into said first flow path of the heat exchanger in order to effect said preheating of the solution, and maintaining a pressure of about 40 to 140 atm. during the hydrolysis reaction and in said second flow path of the heat exchanger.
Claim 2
Dependent Claim
163 words
A continuous process of detoxifying aqueous cyanide solutions comprising the steps of, starting the process cycle by heating a counterflow heat exchanger, then, in successive steps, passing the cyanide solution through a first flow path of said heat exchanger in order to preheat the solution, then, after passing the solution out of the heat exchanger, raising its temperature to a peak of about 200° to 250° C so as to effect a detoxifying hydrolysis of the solution, the solution being heated in said preheating step to more than half of the temperature reached as said peak temperature, and thereafter passing the detoxified solution through a second flow path of the heat exchanger in heat exchange contact with fresh cyanide solution passed into said first flow path of the heat exchanger in order to effect said preheating of the solution, and maintaining a pressure of about 40 to 140 atm. during the hydrolysis reaction and in said second flow path of the heat exchanger.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein the heat exchanger at the start of the reaction cycle is heated to a temperature of about 250° C.
Claim 4
Dependent Claim
52 words
The process of claim 1 wherein the heat exchanger is heated by pumping water of a temperature of about 250° C therethrough and shutting off the flow of water after the heat exchanger has reached the temperature of about 250° C whereupon the pumping of cyanide solution into the heat exchanger commences.
Claim 5
Dependent Claim
22 words
The process of claim 1 wherein the total time at a temperature above 220° C during the hydrolysis reaction is 5 minutes.
Claim 6
Dependent Claim
38 words
The process of claim 1 wherein the pressure increase during the hydrolysis reaction is due to the liberation of ammonia and a pressure higher than said pressure is maintained in said second flow chamber of the heat exchanger.
Claim 7
Dependent Claim
19 words
The process of claim 1 wherein pressure control means are provided to maintain the pressure at the desired rate.
Claim 8
Dependent Claim
32 words
The process of claim 1 wherein the said peak temperature is reached by passing the solution through a heating unit after it has left said first flow path of the heat exchanger.
Claim 9
Dependent Claim
31 words
The process of claim 1 wherein said peak temperature is reached by mixing the cyanide solution with concentrated acid after it has left said first flow path of the heat exchanger.
Claim 10
Dependent Claim
12 words
The process of claim 8 wherein said concentrated acid is sulfuric acid.
Claim 11
Dependent Claim
27 words
The process of claim 9 wherein said sulfuric acid is added to the cyanide solution at a rate not to cause the pH to drop below 7.
Claim 12
Dependent Claim
55 words
The process of claim 9 wherein the cyanide solution is heated in said preheating step to about 150° C which temperature is then raised to a peak of about 250° C by mixing the cyanide solution with said sulfuric acid at a rate not to cause the pH of the solution to drop below 7.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |