Hydrogen unlocks sustainable future for metal sector
Renewable energy technologies including photovoltaic panels and wind turbines require a great deal of metal, which can be highly energy-intensive to produce. Reducing the CO2 footprint of Europe’s metallurgical industry is therefore critical to ensuring that the environmental achievements gained from renewables are fully sustainable. Europe is also highly dependent on metal imports, with global events over the past few years underlining Europe’s overexposure to imported raw materials. Achieving more efficient methods for extracting and recycling useful metals could help to address this.
New techniques to recover metal waste
The EU-funded HARARE(opens in new window) project worked with Europe’s aluminium and copper industries to apply new hydrogen-based techniques to recover waste and produce metal. “Usually, carbon is used for this process,” says HARARE project coordinator Casper Van der Eijk from SINTEF(opens in new window) in Norway. Carbon removes oxygen from metal oxides to produce pure metal and CO2. One of the benefits of using hydrogen as a reductant to convert metal oxides into pure metals is that it produces water vapour instead of CO2. The idea was that using hydrogen could help to minimise the amount of waste produced and puts metals back into society in a way that cuts CO2 emissions. “Achieving a circular economy and becoming less dependent on imports from other countries has also become a political concern,” adds Van der Eijk.
Aluminium, copper and gas producers
The HARARE project sought to not only push forward technological development but also assess the possible environmental and economic benefits of using hydrogen. For this, the team brought on board an aluminium producer and copper producer. “We needed to know if our new hydrogen processes would achieve significant reductions in CO2,” notes Van der Eijk. “Also, from a business point of view, companies need to make money.” A major industrial gas producer was involved in supplying hydrogen, helping the team assess economic viability from a gas supplier point of view. “There is a bit of a chicken and egg discussion going on,” explains Van der Eijk. “Metal producers and gas suppliers are waiting for the other side to invest and create demand before they invest themselves.” One aim of the project was to bring these two halves together, to assess the potential economic benefits of large-scale hydrogen-based metal recycling. Project research partners were also involved in developing new separation technologies and identifying products that could be made from waste materials. These included construction materials produced from so-called red mud, a by-product of bauxite.
Policy action to encourage recycling
Through successfully processing several tonnes of recycled material, the project proved that hydrogen can be effectively used as a reductant. At the moment, the method is perhaps economically most interesting for the recycling of copper given the higher cost of this material. When it comes to making the business case however, the price point of hydrogen remains an issue. “Cheaper hydrogen is needed to make this process viable,” remarks Van der Eijk. “It is difficult now to produce metals from waste material at below market price.” One conclusion of the project therefore is the need for policy action to encourage more recycling. A tax on landfilling for example would make the efficient recycling of metals much more interesting. “If we want to be more self-sufficient, we need to keep more waste materials in the economy and in society,” says Van der Eijk.