Method of recovering metal compounds from solid oxide fuel cell scrap

Patent metadata

Field	Value
Publication number	US-10651479-B2
Application number	US-201815888571-A
Country	US
Kind code	B2
Filing date	Feb 5, 2018
Priority date	Feb 5, 2018
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A method of recovering metal compounds from solid oxide fuel cell scrap includes processing the solid oxide fuel cell scrap to form a powder, digesting the processed scrap, extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap, extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide, and extracting scandium compound from the solution extracting the zirconium compound from the solution.

First claim

The invention claimed is:

1. A method of recovering metal compounds from solid oxide fuel cell scrap, the method comprising:
processing the solid oxide fuel cell scrap to form a powder of processed scrap;
digesting the processed scrap;
extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap;
extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide; and
extracting a scandium compound from the solution after extracting the zirconium compound from the solution.

2. The method of claim 1 , wherein:
the fuel cell scrap comprises ceramic flakes;
processing the solid oxide fuel cell scrap comprises milling or crushing the ceramic flakes to form the powder of the processed scrap;
the powder of the processed scrap has an average particle size of less than about 100 μm; and
the digesting comprises mixing the processed scrap with an acid, while heating the processed scrap.

3. The method of claim 2 , further comprising mixing the digested scrap with water to form the solution containing the digested processed scrap.

4. The method of claim 1 , wherein extracting lanthanum oxide and cerium oxide comprises:
adding a salt to the solution to form a precipitate comprising Ce and La;
filtering the solution to separate the precipitate from a filtrate; and
drying the precipitate to form a cake comprising La 2 O 3 and CeO 2 .

5. The method of claim 4 , where the cake comprises, based on the total weight of the cake:
from about 5 wt % to about 15 wt % CeO 2 ; and
from about 20 wt % to about 30 wt % La 2 O 3 .

6. The method of claim 4 , wherein extracting the zirconium compound from the solution comprises:
adding a first organic extractant to the filtrate, thereby forming a first loaded organic phase comprising complexed Zr;
extracting the first loaded organic phase from the filtrate, thereby generating a raffinate comprising remaining components of the filtrate; and
stripping the Zr from the first loaded organic phase to form the zirconium compound.

7. The method of claim 6 , wherein the zirconium compound comprises ZrOCl 2 or ZrO 2 .

8. The method of claim 6 , wherein the first organic extractant comprises:
an organic tertiary amine Zr complexing agent;
a tridecyl alcohol modifier; and
a kerosene or dearomatized hydrocarbon fluid dilutant.

9. The method of claim 6 , wherein the stripping comprises mixing aqueous HCl with the first loaded organic phase.

10. The method of claim 6 , further comprising:
adding a second organic extractant to the raffinate, thereby forming a second loaded organic phase comprising complexed Sc;
extracting the second loaded organic phase from the raffinate, thereby generating an effluent comprising remaining components of the raffinate; and
stripping the Sc from the second loaded organic phase to form a scandium oxalate.

11. The method of claim 10 , further comprising calcining the scandium oxalate to form Sc 2 O 3 .

12. The method of claim 10 , wherein the second organic extractant comprises:
a dialkyl phosphinic acid scandium complexing agent;
a tri-butyl phosphate modifier; and
a kerosene or dearomatized hydrocarbon fluid dilutant.

13. The method of claim 10 , wherein the stripping the Sc comprises adding oxalic acid to the second loaded organic phase to form the scandium oxalate.

14. The method of claim 10 , further comprising washing the second loaded organic phase with a salt solution, prior to the stripping the Sc.

15. The method of claim 10 , further comprising recovering at least one metal selected from Ni, Mn, or Sr by precipitation from the effluent using at least one of lime or sodium hydroxide.

16. The method of claim 1 , further comprising:
singulating a solid oxide fuel cell stack comprising metal interconnects and solid oxide fuel cells; and
separating the fuel cell scrap from the metal interconnects.

17. The method of claim 16 , wherein the solid oxide fuel cells comprise a scandia and ceria stabilized zirconia electrolyte.

Assignees

• Bloom Energy Corp

Inventors

• Liao Lunzhi
• Hartley Christopher Jeffrey
• Sarmiento Andrew

Classifications

• C22B7/007

  by acid leaching · CPC title

• C01G25/02

  Oxides · CPC title

• C22B59/00

  Obtaining rare earth metals · CPC title

• H01M4/8882

  Heat treatment, e.g. drying, baking · CPC title

• C01G25/003

  Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title