Electrolytic recycling of compounds

Patent metadata

Field	Value
Publication number	US-9605354-B2
Application number	US-201113194391-A
Country	US
Kind code	B2
Filing date	Jul 29, 2011
Priority date	Aug 6, 2010
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

An electrolytic recycling method recovers two or more component elements of one or more compounds simultaneously. A compound, such as a compound semiconductor, to be recycled is dissolved in a liquid electrolyte. Electrolysis of the dissolved compound recovers component elements simultaneously at respective negative and positive electrodes by reduction and oxidation respectively. The component elements produced may be in respective condensed phases or include a gaseous phase.

First claim

What is claimed is:

1. A method of recovering an element, the method comprising:
dissolving a compound having a first element and a second element in a liquid electrolyte contained in a housing, the liquid electrolyte comprising a molten salt, an ionic liquid, or combinations thereof;
electrolyzing the compound in the electrolyte to form an amount of the first element as a liquid by reduction at a first negative electrode and an amount of the second element as a liquid by oxidation at a first positive electrode simultaneously, the first negative and positive electrodes being in the housing, each in contact with the electrolyte; and
removing the amount of the first element and the amount of the second element from the housing.

2. The method of claim 1 wherein the quantity of the compound is incorporated in a multi-part article and further comprising placing the article into the electrolyte.

3. The method of claim 2 wherein the article is a photovoltaic device or a portion thereof.

4. The method of claim 2 wherein the article comprises a metallic phase.

5. The method of claim 2 wherein the article comprises glass.

6. The method of claim 2 wherein the article comprises material insoluble in the electrolyte and further comprising providing a barrier in the electrolyte preventing contact between the insoluble material and the first positive and negative electrodes.

7. The method of claim 1 wherein the compound is a compound semiconductor.

8. The method of claim 1 further comprising fabricating a new batch of the compound using the amount of the first element or the amount of the second element.

9. The method of claim 1 , wherein the first negative electrode, first positive electrode and liquid electrolyte are each at a temperature greater than 500° C. at an operating temperature.

10. The method of claim 1 wherein the amount of the first element and the amount of the second element are removed from the housing during simultaneous generation of the first element and the second element in respective neutral states at the first negative electrode and the first positive electrode respectively.

11. The method of claim 1 wherein an additional quantity of the compound is added to the electrolyte during simultaneous generation of the first element and the second element in respective neutral states at the first negative electrode and the first positive electrode respectively.

12. The method of claim 1 wherein the first element is cadmium and the second element is tellurium.

13. The method of claim 1 wherein the first element is gallium, indium, aluminum, or combinations thereof.

14. The method of claim 1 wherein the second element is tellurium, selenium, sulfur, or combinations thereof.

15. The method of claim 1 wherein the second element is arsenic, antimony, or combinations thereof.

16. The method of claim 1 wherein the amount of the first element removed from the housing contains less than 1% impurity by weight.

17. The method of claim 1 wherein the amount of the second element removed from the housing contains less than 1% impurity by weight.

18. The method of claim 1 , wherein the electrolyte includes a halide salt of the first element.

19. The method of claim 1 , wherein removing the amount of the first element and the amount of the second element from the housing includes:
removing the amount of the first element from the housing through a first removal conduit; and
removing the amount of the second element from the housing through a second removal conduit.

20. A method of recovering cadmium and tellurium from cadmium telluride, the method comprising:
dissolving the cadmium telluride in a liquid electrolyte, contained in a housing, to form respective species bearing cadmium and tellurium, the liquid electrolyte comprising a molten salt, an iconic liquid, or combinations thereof;
electrolyzing the cadmium telluride dissolved in the electrolyte to form an amount of cadmium as a liquid by reduction at a first negative electrode and an amount of tellurium as a liquid by oxidation at a first positive electrode simultaneously, the first negative electrode and the first positive electrode being in the housing, each in contact with the electrolyte; and
removing the amount of cadmium and the amount of tellurium from the housing.

21. The method of claim 20 further comprising:
dissolving a quantity of cadmium sulfide in the liquid electrolyte; and
electrolyzing the cadmium sulfide dissolved in the electrolyte to form an additional amount of cadmium by reduction at the first negative electrode and an amount of sulfur anodically.

22. The method of claim 21 , wherein the amount of sulfur is formed on a second positive electrode in contact with the electrolyte.

23. The method of claim 21 , wherein the housing contains the first negative electrode and the first positive electrode in a first chamber and a second negative electrode and a second positive electrode in a second chamber in fluid communication with the first chamber and the additional amount of cadmium is formed on the second negative electrode and the amount of sulfur is formed on the second positive electrode.

24. The method of claim 21 , wherein the amount of sulfur is formed on a conductive body joining a power source and the first positive electrode.

25. The method of claim 20 wherein the electrolyte includes a cadmium halide.

26. The method of claim 20 , wherein removing the amount of cadmium and the amount of tellurium from the housing includes:
removing the amount of the cadmium from the housing through a first removal conduit; and
removing the amount of the tellurium from the housing through a second removal conduit.

Assignees

• Bradwell David J
• Osswald Sebastian
• Sadoway Donald R
• Massachusetts Inst Technology

Inventors

• Bradwell David J
• Osswald Sebastian
• Sadoway Donald R

Classifications

• C25B1/00

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C25C3/34

  of metals not provided for in groups C25C3/02 - C25C3/32 · CPC title

• C25C1/00 Primary

  Electrolytic production, recovery or refining of metals by electrolysis of solutions (C25C5/00 takes precedence) · CPC title

• C22B7/006

  Wet processes · CPC title

• Y02P10/234

  Cross-Sectional Technologies · mapped topic