An economical process with green hydrogen can be used to extract CO2-free iron from the red mud generated in aluminium production.
An economical process with green hydrogen can be used to extract CO2-free iron from the red mud generated in aluminium production.
The production of aluminium generates around 180 million tonnes of toxic red mud every year. Scientists at the Max-Planck-Institut für Eisenforschung, a centre for iron research, have now shown how green steel can be produced from aluminium production waste in a relatively simple way. In an electric arc furnace similar to those used in the steel industry for decades, they convert the iron oxide contained in the red mud into iron using hydrogen plasma. With this process, almost 700 million tonnes of CO2-free steel could be produced from the four billion tonnes of red mud that have accumulated worldwide to date – which corresponds to a good third of annual steel production worldwide. And as the Max Planck team shows, the process would also be economically viable.
According to forecasts, demand for steel and aluminium will increase by up to 60 percent by 2050. Yet the conventional production of these metals has a considerable impact on the environment. Eight percent of global CO2 emissions come from the steel industry, making it the sector with the highest greenhouse gas emissions. Meanwhile, luminium industry produces around 180 million tonnes of red mud every year, which is highly alkaline and contains traces of heavy metals such as chromium. In Australia, Brazil and China, among others, this waste is at best dried and disposed of in gigantic landfill sites, resulting in high processing costs. When it rains heavily, the red mud is often washed out of the landfill, and when it dries, the wind can blow it into the environment as dust. In addition, the highly alkaline red mud corrodes the concrete walls of the landfills, resulting in red mud leaks that have already triggered environmental disasters on several occasions, for example in China in 2012 and in Hungary in 2010. In addition, large quantities of red mud are also simply disposed of in nature.
Read more at Max-Planck-Gesellschaft
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