28 January, 2020
In today’s urbanised world, steel is everywhere. It’s used in everything from critical infrastructure like roads and railways, through to earthquake-resilient buildings, wind turbines and electric vehicles. But making steel comes with a significant environmental cost.
In 2018, the IPCC reported that the global iron and steel industry was responsible for producing 2.6 Gt of carbon dioxide (CO2) per year; that’s 7 % of the world’s total CO2 emissions. New Zealand’s contribution to that, according to a recent report from the Ministry for the Environment, was equivalent to about 1,750 kilotonnes of CO2 per year.
These numbers go some way to explaining why New Scientist magazine in November described heavy industries as the final frontier in the fight against climate change. As countries race to reduce their environmental impact, they’re beginning to re-evaluate how they manufacture essential materials. New Zealand researchers are working to clean up the production of steel and vanadium, by moving away from carbon.
“The source of all this CO2 is the chemical reduction of iron ore,” says MacDiarmid researcher Dr Chris Bumby. “Modern ironmaking is an industry based on the incremental development of a 2000-year-old process.” So while a time-traveller from the Iron Age would be astonished by the scale and complexity of a modern smelting plant, they’d certainly recognise the fundamental chemistry that supports it.