Purification of NaCl brine containing iodine

Patent metadata

Field	Value
Publication number	US-11040903-B2
Application number	US-201615273740-A
Country	US
Kind code	B2
Filing date	Sep 23, 2016
Priority date	Oct 5, 2015
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

The present invention provides a process for separating iodine from a NaCl brine, comprising the following steps: (a) providing said NaCl brine containing iodide, (b) adjusting the pH of said NaCl brine to be no greater than 1.5, (c) adding oxidizing agent, such as chlorine containing oxidizing agent, to said NaCl brine resulting from step (b) to obtain an oxidation-reduction potential in said NaCl brine of from 560 mV to 925 mV, the combination of said pH of no greater than 1.5 and oxidation-reduction potential of 560 mV to 925 mV resulting in the formation of an iodine-chlorine anionic complex, and (d) contacting nonionic adsorption resin and said NaCl brine from step (c) one with the other to adsorb said iodine from this brine, to obtain as a result thereof NaCl brine wherein the iodine content therein is preferably no greater than 100 ppbw, more preferably no greater than 10 ppbw.

First claim

What is claimed is:

1. Process for separating iodine from a NaCl brine, comprising the following sequential steps:
(a) providing NaCl brine containing at least 4 wt % NaCl and containing iodide,
(b) adjusting the pH of said NaCl brine from step (a) to be no greater than 1.5,
(c) adding oxidizing agent to said NaCl brine from step (b) to obtain an oxidation-reduction potential in said NaCl brine of from 560 mV to 925 mV, the combination of said pH of no greater than 1.5 and oxidation-reduction potential of 560 mV to 925 mV resulting in the formation of an iodine-chlorine anionic complex, and
(d) contacting a non-functionalized, nonionic adsorption resin and said NaCl brine from step (c) one with the other to adsorb said iodine from said brine from step (c).

2. The process of claim 1 wherein the NaCl brine of step (a) contains 17 to 25 wt % of said NaCl.

3. The process of claim 1 wherein said adjusting of step (a) is carried out by adding HCl to said NaCl brine.

4. The process of claim 1 wherein said oxidizing agent is alkali or alkaline earth metal hypochlorite.

5. The process of claim 4 wherein said oxidizing agent is sodium hypochlorite.

6. The process of claim 1 wherein said oxidizing is carried out at a temperature of from 15 to 50° C.

7. The process of claim 1 and additionally eluting said iodine from said nonionic adsorption resin.

8. The process of claim 1 wherein the result of step (d) is that NaCl brine thereof has an iodine content therein no greater than 100 ppbw.

9. The process of claim 8 wherein the iodine content of said brine is no greater than 10 ppbw.

10. The process of claim 1 wherein said pH is no greater than 1.4.

11. The process of claim 1 wherein said pH is no greater than 1.3.

12. The process of claim 1 wherein said pH is no greater than 1.2.

13. The process of claim 1 wherein said pH is no greater than 1.1.

14. The process of claim 1 wherein said pH is no greater than 1.0.

Assignees

• Chemours Co Tt Llc
• Chemours Co Fc Llc

Inventors

• Breske Stephen Thomas
• Helberg Lisa Edith
• Hill Peter

Classifications

• C01B7/14

  Iodine · CPC title

• C01D3/145

  by solid ion-exchangers or solid chelating agents · CPC title

• C02F2209/04

  Oxidation reduction potential [ORP] · CPC title

• C02F2101/12

  Halogens or halogen-containing compounds · CPC title

• C02F1/66

  by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58) · CPC title