Process for recovering heavy metal ions

Patent metadata

Field	Value
Publication number	US-10723633-B2
Application number	US-201615392038-A
Country	US
Kind code	B2
Filing date	Dec 28, 2016
Priority date	Dec 31, 2015
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

A process is provided for recovering a heavy metal from a waste stream resulting from a process for producing aromatic carboxylic acid by liquid-phase oxidation of an aromatic feedstock compound in the presence of a heavy metal catalyst. The process comprises: (a) producing a carbonate salt precipitate of the heavy metal by adding a source of metal ions and carbonate or bicarbonate ions into the waste stream; (b) separating the precipitate from the waste stream; (c) washing the precipitate with an alkali solution having metal ions therein, wherein at least a portion of the metal ions in the alkali solution are the same as at least a portion of metal ions in the source of metal ions and carbonate or bicarbonate ions; and, (d) recovering the washed precipitate wherein the washed precipitate comprises the heavy metal ions. In one embodiment, the aromatic carboxylic acid comprises terephthalic acid.

First claim

What is claimed is:

1. A process for recovering a heavy metal from a waste stream resulting from a process for producing aromatic carboxylic acid by liquid-phase oxidation of an aromatic feedstock compound in the presence of a heavy metal catalyst, comprising:
a) producing a carbonate salt precipitate of the heavy metal by adding a source of metal ions and carbonate or bicarbonate ions into the waste stream;
b) separating the carbonate salt precipitate from the waste stream;
c) washing the precipitate with an alkali solution having metal ions therein, wherein at least a portion of the metal ions in the alkali solution are the same as at least a portion of metal ions in the source of metal ions and carbonate or bicarbonate ions, wherein washing the carbonate salt precipitate is performed without resuspending the precipitate; and
d) recovering the washed precipitate wherein the washed precipitate comprises the carbonate salt precipitate of the heavy metal ions.

2. The process of claim 1 , wherein the aromatic carboxylic acid comprises terephthalic acid.

3. The process of claim 2 , wherein the aromatic feedstock compound comprises para-xylene.

4. The process of claim 1 , wherein the source of metal ions and carbonate or bicarbonate ions is added until pH is 7 to 9.5.

5. The process of claim 1 , further comprising washing the washed precipitate with water before recovering the precipitate.

6. The process of claim 1 , wherein the source of metal ions and carbonate or bicarbonate ions is sodium carbonate, sodium bicarbonate or a mixture thereof.

7. The process of claim 6 , wherein the alkali solution in step (c) is sodium hydroxide solution.

8. The process of claim 1 , further comprising converting the carbonate salt of the heavy metal into catalyst suitable for use in the process for producing aromatic carboxylic acid.

9. The process of claim 7 , wherein the precipitate recovered in step (d) comprises sodium ions, and wherein the process further comprising quantitating the sodium ions in the precipitate recovered in step (d).

10. The process of claim 1 , wherein the waste stream comprises acetate ions.

11. The process of claim 1 , wherein the waste stream comprises cobalt acetate and manganese acetate.

12. The process of claim 9 , wherein the atomic ratio of cobalt to sodium in the precipitate recovered in step (d) is at least 10.

13. A process for recovering cobalt from a liquid medium containing a basic cobalt salt, comprising:
a) producing a cobalt carbonate precipitate by adding a source of metal ions and carbonate or bicarbonate ions into the liquid medium;
b) separating the cobalt carbonate precipitate from the liquid medium;
c) washing the cobalt carbonate precipitate with an alkali solution having metal ions therein, wherein the metal ions in the alkali solution are the same as the metal ions in the source of metal ions and carbonate or bicarbonate ions, the washing being performed without resuspending the precipitate; and
d) recovering cobalt from the washed precipitate in the form of cobalt carbonate.

14. The process of claim 13 , wherein the basic cobalt salt is cobalt acetate.

15. The process of claim 13 , wherein the source of metal ions and carbonate or bicarbonate ions is sodium carbonate, sodium bicarbonate or a mixture thereof.

16. The process of claim 15 , wherein the alkali solution is sodium hydroxide solution.

17. The process of claim 15 , wherein the concentration of the sodium hydroxide solution is at least 0.5%.

18. The process of claim 13 , further comprising converting the cobalt carbonate into the basic cobalt salt.

19. The process of claim 16 , wherein the washed precipitate of step (c) comprises sodium ions, and the atomic ratio of cobalt to sodium in precipitate of step (c) is at least 10.

20. A process for recovering a heavy metal from a waste stream resulting from a process for producing aromatic carboxylic acid by liquid-phase oxidation of an aromatic feedstock compound in the presence of a heavy metal catalyst, comprising:
a) producing a carbonate salt precipitate of the heavy metal by adding a source of metal ions and carbonate or bicarbonate ions into the waste stream; then
b) separating the carbonate salt precipitate from the waste stream; then
c) washing the separated carbonate salt precipitate with a solution of metal hydroxide, wherein at least a portion of the metal of the metal hydroxide solution is the same as the metal of at least a portion of the metal ions in the source of metal ions and carbonate or bicarbonate ions, the washing being performed without resuspending the precipitate; and then
d) recovering the washed precipitate wherein the washed precipitate comprises the carbonate salt precipitate of the heavy metal ions.

21. The process of claim 20 , wherein the metal of the metal hydroxide solution is sodium and the metal of the metal ions of the source of metal ions and carbonate or bicarbonate ions is sodium.

Assignees

• Bp Corp North America Inc

Inventors

• Gemoets Dominique
• Verbeeck Wim

Classifications

• C07C51/00

  Preparation of carboxylic acids or their salts, halides or anhydrides (of acids by hydrolysis of oils, fats or waxes C11C) · CPC title

• C07C51/487

  by treatment giving rise to chemical modification (by chemisorption C07C51/47) · CPC title

• C01G51/06 Primary

  Carbonates · CPC title

• C02F2103/36

  from the manufacture of organic compounds · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title