Process and apparatus for generating bromine

• US 5,679,239 A
• Filed: 10/08/1996
• Issued: 10/21/1997
• Est. Priority Date: 03/27/1995
• Status: Expired due to Fees

• Current Assignee: US Filter Wastewater Group Incorporated (Siemens AG)
• Original Assignee: Electrocatalytic, Inc.
• Inventors: Zolotarsky, Vadim, Blum, David B., Sergent, Rodney H.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Mee, Brendan
• Application Number:
  US08/727,133
• Time in Patent Office: 378 Days
• Field of Search: 205/556, 205/619
• US Class Current: 205/556
• CPC Class Codes: C02F 1/4674 with halogen or compound of halogens, e.g. chlorine, bromine
• CPC Class Codes: C02F 1/766 by means of halogens other than chlorine or of halogenated compounds containing halogen other than chlorine
• CPC Class Codes: C02F 2001/46133 characterised by the material
• CPC Class Codes: C02F 2201/4612 Controlling or monitoring
• CPC Class Codes: C02F 2201/4618 Supplying or removing reactants or electrolyte
• CPC Class Codes: C02F 2209/06 pH
• CPC Class Codes: C22B 11/04 by wet processes extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26
• CPC Class Codes: C25B 1/24 Halogens or compounds thereof

Abstract

The present invention provides a process for generating an aqueous solution containing at least one active bromine compound comprising the steps of: electrolyzing an aqueous solution containing bromide ions so that bromate ions are formed in said aqueous solution; and introducing to the aqueous solution containing bromate ions an acid to generate an aqueous solution containing at least one active bromine compound. The present invention also provides an apparatus for generating an aqueous solution containing at least one active bromine compound. The aqueous solution containing the active bromine compound(s) generated using the process and apparatus of the present invention may be used for water treatment and the recovery of precious metals such as gold.

Claims

1. A process for generating an aqueous solution containing at least one active bromine compound comprising the steps of:

electrolyzing an aqueous solution containing bromide ions at an alkaline pH resulting in an increased concentration of bromate ions in the aqueous solution; and

introducing to the aqueous solution containing bromate ions an acid to generate an aqueous solution containing at least one active bromine compound.

2. The process of claim 1, wherein the source of bromide ions is sodium bromide.

3. The process of claim 1, wherein the concentration of bromide ions in the solution before electrolysis is about 0.25 to 45% by weight.

4. The process of claim 1, wherein the concentration of bromide ions in the solution before electrolysis is about 0.25 to 15% by weight.

5. The process of claim 1, wherein the pH of the aqueous solution containing bromate ions is about 8-12.

6. The process of claim 1, wherein the acid is selected from the group consisting of sulfuric acid, hydrochloric acid, hydrobromic acid, sulfamic acid, and phosphoric acid.

7. The process of claim 1, wherein the acidified solution has a pH of about less than 4.

8. The process of claim 1, wherein the acidified solution has a pH of about less than 2.

9. The process of claim 1, wherein the acidified solution has a pH of about less than 1.

10. The process of claim 1, wherein the aqueous solution containing at least one active bromine compound is substantially free of bromate ions.

11. The process of claim 1, wherein the active bromine compound is selected from the group consisting of bromine, hypobromous acid, hypobromite ion, and hydrogen tri-bromide.

12. The process of claim 1, wherein the aqueous solution containing bromide ions further comprises chloride ions.

13. The process of claim 12, wherein the source of chloride ions is sodium chloride.

14. The process of claim 12, wherein the concentration of bromide and chloride ions in the solution before electrolysis is about 0.25 to 45% by weight.

15. The process of claim 12, wherein the concentration of bromide and chloride ions in the solution before electrolysis is about 0.25 to 15% by weight.

16. The process of claim 12, wherein the active bromine compound is selected from the group consisting of bromine, hypobromous acid, hypobromite ion, hydrogen tri-bromide, and bromine chloride.