Method of recovering metal compounds from solid oxide fuel cell scrap

Patent metadata

Field	Value
Publication number	US-2019245216-A1
Application number	US-201815888571-A
Country	US
Kind code	A1
Filing date	Feb 5, 2018
Priority date	Feb 5, 2018
Publication date	Aug 8, 2019
Grant date	—

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

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 scandium compound from the solution 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 1 , 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.

18 . A method of recovering lanthanum oxide and cerium oxide from solid oxide fuel cell scrap, the method comprising:
processing the scrap, such that the scrap has an average particle size of less than about 100 μm; digesting the processed scrap; mixing the digested scrap with water to form a solution; 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 .

19 . The method of claim 18 , 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 .

20 . The method of claim 18 , further comprising:
singulating a solid oxide fuel cell stack comprising metal interconnects and solid oxide fuel cells; and separating the scrap from the metal interconnects.

Assignees

• Bloom Energy Corp

Inventors

• Liao Lunzhi
• Hartley Christopher Jeffrey
• Sarmiento Andrew

Classifications

• H01M4/8875

  Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support · CPC title

• H01M4/9066

  of metal-ceramic composites or mixtures, e.g. cermets · CPC title

• H01M8/008 Primary

  Disposal or recycling of fuel cells · CPC title

• H01M8/1253

  the electrolyte containing zirconium oxide · CPC title

• H01M4/8882

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