95 % of platinum can be recycled with new method

Platinum is a metal of great importance to the national economy, our climate and the transition to a more sustainable society. Platinum is e.g. the best catalyst for fuel cells, which several researchers consider a central technology in our transition to renewable energy.

Platinum also plays a central part in the catalytic converters of petrol and diesel cars. Without platinum, the pollutants from the engine would not be removed from the exhaustion gas.

Researcher Shuang Ma Andersen from SDU Chemical Engineering has developed an affordable and environmentally friendly method of recycling the important metal. The method recycles more than 95 % of all platinum in industrial scrap metal.

Gentle process

- The process is an electrochemical reaction, where we use diluted acid to separate platinum from industrial scrap metal. It is a gentle process that allows us to preserve other valuable elements of the scrap metal, such as polymers, Shuang Ma Andersen says. She has recently secured a patent for the method.

The method is far more environmentally friendly than the current method of recycling platinum. Today, a method called pyrometallurgy is used. It simply means that the metals in the industrial scrap are separated through exposure to very high temperatures.

- For around 50 years we have recycled platinum by burning industrial scrap metal. That requires ovens that can handle temperatures above 1500 ˚C. In addition, other resourceful elements are burned in the process, and toxins are formed. It is a shame, and it is far from environmentally friendly, Shuang Ma Andersen points out.

Increased demand

The EU has put fuel cells on its list of critical raw materials, and the global industrial demand for platinum metals is increased with around 12.5 % each year.

Meanwhile, the security of supply is not optimal as countries such as South Africa and Russia are home to the vast majority, 85 %, of the global reserves of platinum.

- That is why it is so important that we recycle platinum, so we can use this valuable metal over and over again, says Shuang Ma Andersen, associate professor at SDU Chemical Engineering.

Fuel cells are burned

She also points to a serious problem with reusing platinum from fuel cells, which are e.g. used in eco-friendly hydrogen cars.

- I am guessing that the platinum from fuel cells is currently being recycled through burning. That creates a massive environmental issue, because a biproduct of the process is hazardous fluorine gases that are 10,000 times more potent that carbondioxide. The gases also corrode the ovens where the fuel cells are burnt.

- It is actually illegal to do, but as the use of fuel cells is not widespread yet, there has probably been made exceptions, or the hazardous gases are being contained before exhaustion, Shuang Ma Andersen guesses.

- But those gases are not formed when using my method, Shuang Ma Andersen explains. She also stresses the importance of developing a sustainable way of recycling platinum from fuel cells, before the cells become a commercial success.

Grant from innovation fund

Shuang Ma Andersen has received an Innoexplorer grant from Innovation Fund Denmark to develop her results for commercial use, and she is in dialogue with potential industrial collaborators to further the commercial potential of her research results.