A “breakthrough” next step in New Zealand’s journey to decarbonising steel

Could water be the answer to New Zealand’s steel industry lowering carbon emissions? Researchers at Te Herenga Waka – Victoria University’s Robinson Research Institute collaborate with Wellington UniVentures and New Zealand Steel to test exactly that.

“What really motivates me is finding really difficult problems to solve… But alongside that, it’s if we solve it, this actually has the potential to have world-changing impact,” says Dr Chris Bumby, principal scientist at the Robinson Research Institute.

Bumby and his team have developed a novel technology which uses hydrogen instead of coal to produce iron and steel, potentially eliminating carbon dioxide emissions from the country’s steel industry. Now in a new project in collaboration with Wellington UniVentures and New Zealand Steel, the aim is to accelerate the development of a pilot-scale plant for this process.

In New Zealand, 55% of industrial emissions are a result of steel and iron production – totaling 5% of total gross emissions. However, the problem is that producing iron currently relies on a chemical reaction between coal and iron ore, which results in the emission of large quantities of CO2.

“If we are going to do something about those CO2 emissions, we have to think very carefully about the underlying chemistry of how we make iron metal,” says Bumby, with the fundamental chemistry of the process having largely remained the same since the Iron Age.

“However, with the approach we’re looking at, and there is other work going on around the world to do this, it is looking at using hydrogen. By using hydrogen, we take carbon out of the equation completely. And what we do is we change this reaction so that instead of having carbon plus iron oxide, we now have hydrogen plus iron oxide. So our product, instead of being carbon dioxide, and the carbon process, is now water – hydrogen plus iron oxide gives water and iron. That water comes off as water vapour. It is steam, with no environmental impact.”

In New Zealand, iron is produced from titanomagnetite ironsand, which is an “unusual” form of iron ore containing low levels of titanium oxide. Through Bumby’s process, by replacing hydrogen for coal, the hydrogen reacts with this ironsand in a custom built fluidised-bed reactor at temperatures up to 1,000°C to produce very high-purity iron.

Since the project kickstarted in 2019, it has received $6.5 million from the MBIE Endeavour Fund. With a unified goal to produce safe and sustainable steel, the new funding of $750,000 over three years from New Zealand Steel will accelerate the engineering development of this research.

“We’re in the throes of a climate crisis and eliminating coal from the steelmaking process will significantly contribute to lowering global CO2 emissions,” says Bumby.

“New Zealand’s abundant renewable electricity supply can be used to produce ‘green hydrogen’ and electrically heat the reactor, resulting in a process that does not emit carbon dioxide at all.”

Anne Barnett, Wellington UniVentures’ CEO, adds: “Hydrogen steelmaking will be vital to securing a zero-carbon future, and it also presents a huge economic opportunity for New Zealand. We are excited to be partnering with NZ Steel in this first step towards pilot-scale demonstration of our process. Full-scale industrial commercialisation will of course require much more investment, and we look forward to engaging with a range of other investors in the coming years.”

Did you know?

  • The earliest steel product is 4,000 years old.
  • With the rate of steel production across the world, 548 Eiffel Towers could be built with the production of steel in one day.
  • The Bronze Age gave way to the Iron Age, because iron was easier to find and work with.
  • The amount of energy required to produce steel has been halved in the past 50 years.