METHOD FOR COMMINUTING SPENT, CATALYST-COATED POLYMER ELECTROLYTE MEMBRANES

Abstract

A method for comminuting spent, catalyst-coated PEM membranes from PEM fuel cells and/or PEM electrolysis cells by means of a cutting mill.

Claims

1. A method for comminuting spent, catalyst-coated PEM membranes from PEM fuel cells and/or PEM electrolysis cells, wherein the comminution is performed by means of a cutting mill.

2. The method according to claim 1, wherein the spent, catalyst-coated PEM membranes are provided with elastic seals.

3. The method according to claim 1, wherein the catalyst-coated PEM membranes are identical or different catalyst-coated PEM membranes.

4. The method according to claim 1, wherein the method is carried out batchwise or continuously.

5. The method according to claim 1, wherein the comminution process is performed until a desired comminution result is achieved.

6. The method according to claim 2, wherein the comminution is performed only until a desired comminution result is achieved with regard to the fraction of catalyst-coated PEM membrane in the comminuted grinding material.

7. The method according to claim 2, wherein, after the comminution process has ended, the coarse-grained fraction of comminuted elastic seal is separated from the fine-grained fraction of catalyst-coated PEM membrane.

8. The method according to claim 7, wherein the separation is performed by means of screening.

9. The method according to claim 7, wherein the separated fine-grained fraction is sampled, analyzed with regard to the type and proportion of noble metal and/or subjected to noble metal recycling.

10. The method according to claim 7, wherein the separation or screening is performed during the comminution process by means of a screening device integrated into the cutting mill.

Description

EXEMPLARY EMBODIMENT

[0019] 93.88 g of spent, catalyst-coated polymer electrolyte membranes from PEM fuel cells provided with edge seals made of silicone elastomer were comminuted in a cutting mill (model SM 300 from Retsch GmbH, Retsch-Allee 1-5, 42781 Haan, Germany) equipped with a bottom screen with square perforations of 3 mm3 mm in batch operation lasting 30 seconds. This resulted in 76.33 g of fine-grained fraction and 17.55 g of coarse-grained, above-screen fraction. After ashing and wet-chemical processing of the ash residue, both fractions were examined for their noble metal content by means of ICP-OES. The following table shows the results obtained for the two fractions:

TABLE-US-00001 Fine-grained fraction Above-screen fraction Weight 76.33 g 17.55 g Particle size >0 to 3 mm >3 to 6 mm Platinum content 2.62 wt. % 0.12 wt. % Ruthenium content 0.22 wt. % 0.01 wt. %