Stacking solutions to help the iron ore industry reach net zero.

By Dr Kwaku Owusu.

My name is Kwaku Owusu, I’m developing innovative low-emission steelmaking processes within the Mineral Resources business unit at CSIRO.  

We know that producing low-emissions steel is a challenge. It is a challenge that will be solved through multiple innovations. In the roadmapping work, I have been involved with industry and stakeholders in comparing different low-emissions pathways for steelmaking. 

We hear, rightly a lot about how we can move to 100% Hydrogen Direct Reduction over the next decades (possibly by 2050) to fully transform the steel industry. The success of this transition hinges upon the development of cost-efficient methods for producing green hydrogen on a commercial scale. 

As we look forward to a sustainable transition of the industry to low emissions, there are other steps we can take to reduce the carbon intensity of pig iron production and steelmaking. These steps will be important to support markets in the interim—i.e. the application of renewable carbon energy source in iron and steelmaking. 

It turns out that the iron ore concentrations in some of our tailings or mining waste are higher than in some low-grade ores being mined.

I’m working on is the use of biochar as a renewable carbon energy source to assist in the recovery of iron from tailings as an alternative and sustainable feedstock in ironmaking.   

If we do this, we not only reduce the carbon intensity of products but create the possibility of cost savings in tailings/mining waste disposal and management.  

So, we blend biochar and tailings then heat the mixture at a low temperature. In the process, different iron oxides in the mining waste such as hematite and goethite are converted to the magnetite phase, which can then be readily extracted by magnetic separation.   

Early results are showing recovery rates of more than 85 % for an energy-efficient low temperature. Next, we are doing optimisation studies to increase recovery rates to over 90% while reducing the processing time. 

Like many aspects of net zero and climate change actions, the solution will not be a single silver bullet, or at least not straight away. We need to stack multiple innovations into new cost-effective value chains. 

My research seeks to ensure that the Australian steel industry meets its net zero goals while maintaining economic viability and innovative edge.