The iron-making process is very toxic for the environment and it contributes to climate change so scientists from the United States and China have found a new production method, with zero pollution.
Iron metal is produced in the same way since the industrial revolution: iron ore is melted at temperatures over 2000°C in a blast furnace, and huge amounts of CO2 are released into the atmosphere.
Two scientists - Stuart Licht at George Washington University in Washington, DC and Baohui Wang at Northeast Petroleum University in Daqing – found a new way of making iron, that reduces industrial carbon dioxide emissions by a quarter worldwide.
To obtain a “green” iron production, completely CO2-free, iron ores Fe2O3 and Fe3O4 can be dissolved in molten lithium carbonate and temperatures of only 800°C, even if this was previously thought to be impossible.
After that, all it takes is an electrical current to the molten mix that will separate the iron ore into iron and oxygen, which can be collected by two electrodes.
This new way is completely green because of the zero carbon dioxide emissions, of the fewer energy required to generate the lower temperatures and power the electrolysis and also because all this can be achieved by using renewable energy, as Licht explains.
The same team developed a recent solar technique which they called solar thermal electrochemical photo or Step, that uses the Sun's thermal energy to melt the lithium carbonate solution and the visible light energy to power the electrolysis.
“Step production of iron would be cost effective, and could allow iron production facilities to be housed in new geographic locations, such as in closer to urban centers or in high sunlight geographies,” said Licht.
“If the Step process can be performed at industrial scale, it holds considerable promise, says Neal Woodbury, a renewable energy expert at Arizona State University, US.
“Of particular note is that it should be possible to utilize waste heat from the processes that produce the required electricity, thus decreasing the energy input as well.”
So the team's next challenge is to adapt the laboratory Step process to an industrial scale, according to the Royal Society of Chemistry