Method and system for the treatment of cyanide-containing fluids

Patent metadata

Field	Value
Publication number	US-11667553-B2
Application number	US-201716091601-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Apr 8, 2016
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

A method and system for treating cyanide-containing fluids, in particular cyanide-containing waste water, wherein cyanide-containing fluid is subject to a pretreatment in a pretreatment zone, in which at least one predetermined pH value and a predetermined temperature is set, wherein a base fluid is formed with the pretreatment. Base fluid is reacted at least with an oxidation means in at least one reaction reactor, whereby an oxidation reaction of the cyanide is initiated. Fluid from the reaction reactor is transferred as intermediate fluid into at least one process reactor, in which conditions exist in which the oxidation reaction of the cyanide initiated in the reaction reactor can take place, wherein a process fluid is formed. A continuous flow of fluid is maintained at least periodically, wherein the base fluid is transferred continuously from the pretreatment zone into the reaction reactor, intermediate fluid is transferred continuously from the reaction reactor into the process reactor, and process fluid is removed continuously from the process reactor.

First claim

What is claimed is:

1. A method for treating cyanide-containing liquids comprising the steps of:
subjecting cyanide-containing liquid to a pretreatment in a pretreatment zone wherein at least a specified pH using a pH modifier and a specified temperature are established, the pretreatment forming a base liquid;
transferring the base liquid to at least one reaction reactor located downstream from the pretreatment zone;
providing a first amount of an oxidizing agent to the at least one reaction reactor in a controlled manner and admixing the base liquid in the at least one reaction reactor with at least the oxidizing agent, thereby initiating an oxidation reaction of cyanides in the cyanide-containing liquid;
selectively supplying the pH modifier to the at least one reaction reactor independently of any pH modifier supplied to the pretreatment zone;
selectively supplying a catalyst to the at least one reaction reactor;
transferring liquid from the at least one reaction reactor as intermediate liquid into at least one process reactor located downstream from the at least one reaction reactor;
providing a second amount of the oxidizing agent to the at least one process reactor in a controlled manner, the second amount of the oxidizing agent being provided to the at least one process reactor being independent of the first amount of the oxidizing agent provided to the at least one reaction reactor, the at least one process reactor having conditions under which the cyanide oxidation reaction initiated in the at least one reaction reactor is able to proceed, forming a process liquid;
selectively supplying the pH modifier to the at least one process reactor independently of any pH modifier supplied to the pretreatment zone or the at least one reaction reactor;
analyzing a cyanide content of the base liquid, the intermediate liquid treated with the oxidizing agent and removed from the at least one reaction reactor, and the process liquid treated with the oxidizing agent and removed from the at least one process reactor, and selectively adjusting one or more of a pretreatment temperature, the first amount of the oxidizing agent, the second amount of the oxidizing agent, or the catalyst, in response to the cyanide content of the base liquid, the intermediate liquid removed from the at least one reaction reactor and/or the process liquid removed from the at least one process reactor; and
maintaining at least periodically a continuous liquid stream, wherein
the base liquid is transferred continuously from the pretreatment zone into the at least one reaction reactor;
the intermediate liquid is transferred continuously from the at least one reaction reactor into the at least one process reactor; and
the process liquid is withdrawn continuously from the at least one process reactor.

2. The method as claimed in claim 1 , wherein the oxidizing agent is hydrogen peroxide.

3. The method as claimed in claim 1 , wherein the catalyst is copper in the form of a copper sulfate solution and/or the pH modifier is aqueous sodium hydroxide solution.

4. The method as claimed in claim 1 , wherein the base liquid and/or the intermediate liquid and/or the process liquid is returned into the pretreatment zone by means of an analytical circuit facility, the analytical circuit facility ascertaining the cyanide concentration in the liquid returned into the pretreatment zone.

5. The method as claimed in claim 1 , wherein the process liquid is returned demand-dependently into the pretreatment zone.

6. The method as claimed in claim 1 , wherein the process liquid on withdrawal is transferred at least partly into a storage vessel, and liquid from the storage vessel is returned demand-dependently into the pretreatment zone.

7. The method as claimed in claim 1 , wherein the pH in the continuous liquid stream is held largely constant.

8. A plant for treating cyanide-containing liquids comprising:
a pH reservoir holding a pH modifier;
a catalyst reservoir holding a catalyst;
a pretreatment zone, in which cyanide-containing liquid is subjected to a pretreatment wherein the pH modifier is provided so that at least a specified pH and a specified temperature of the cyanide-containing liquid is established, the pretreatment forming a base liquid;
at least one reaction reactor located downstream from the pretreatment zone;
a first line to provide a first amount of oxidizing agent to the at least one reaction reactor and a catalyst line to provide the catalyst to the at least one reaction reactor, wherein the base liquid transferred from the pretreatment zone is admixed at least with the first amount of the oxidizing agent and the catalyst, thereby initiating an oxidation reaction of cyanides in the cyanide-containing liquid in the at least one reaction reactor;
a first pH branch line selectively supplying the pH modifier to the at least one reaction reactor;
liquid from the at least one reaction reactor can be transferred as intermediate liquid into at least one process reactor;
a second line providing a second amount of the oxidizing agent to the at least one process reactor, the second amount of the oxidizing agent being independent of the first amount of the oxidizing agent, and further wherein conditions prevail in the at least one process reactor so that the cyanide oxidation reaction initiated in the at least one reaction reactor is able to proceed, forming a process liquid;
a second pH branch line selectively supplying the pH modifier to the at least one process reactor;
a first analytical circuit line continuously providing the base liquid from the pretreatment zone to a cyanide analysis facility to monitor an amount of cyanide in the base liquid;
a second analytical circuit line continuously providing the intermediate liquid from the at least one reaction reactor to the cyanide analysis facility to monitor an amount of cyanide in the intermediate liquid;
a third analytical circuit line continuously providing process liquid from the at least one process reactor to the cyanide analysis facility to monitor an amount of cyanide in the process liquid; and
a continuous liquid stream is at least periodically maintained by means of a pump system wherein
the base liquid is transferred continuously from the pretreatment zone into the at least one reaction reactor;
the intermediate liquid is transferred continuously from the at least one reaction reactor into the at least one process reactor; and
the process liquid is withdrawn continuously from the at least one process reactor.

9. The plant as claimed in claim 8 , wherein the oxidizing agent is hydrogen peroxide.

10. The plant as claimed in claim 8 , wherein additionally a catalyst by means of a catalyst metering facility, and/or the pH modifier by means of a pH metering facility, is added demand-dependently to the at least one reaction reactor.

11. The plant as claimed in claim 10 , wherein the catalyst is copper in the form of a copper sulfate solution and/or the pH modifier is aqueous sodium hydroxide solution.

12. The plant as claimed in claim 8 , wherein a pH modifier by means of a pH metering facility, and/or an oxidizing agent by means of an oxidizing agent metering facility, is added demand-dependently to the at least one process reactor.

13. The plant as claimed in claim 8 , wherein the base liquid and/or the intermediate liquid and/or the process liquid is returned into the pretreatment zone by means of an analytical circuit facility, the analytical circuit facility being able to ascertain the cyanide concentration in the liquid returned into the pretreatment zone.

14. The plant as claimed in claim 8

Assignees

• Eisenmann Se

Inventors

• Schumacher Jochen

Classifications

• C02F2103/343

  from the pharmaceutical industry, e.g. containing antibiotics · CPC title

• C02F2301/08

  Multistage treatments, e.g. repetition of the same process step under different conditions · CPC title

• C02F2209/003

  Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process · CPC title

• C02F2209/02

  Temperature · CPC title

• C02F2103/10

  from quarries or from mining activities · CPC title