At last, a less destructive method for getting rid of dangerous “red mud” for the environment.
There is a shadowy side to aluminium, which is one of the metals that is employed in manufacturing the most frequently. Byproducts of its manufacturing include bauxite residue, also known as “red mud,” which is characterised by a pH that is extremely basic and contains minerals that are poisonous to humans. It would be a terrible idea to let red mud back into the environment because doing so will contaminate ecosystems and lead to the contamination of local water supplies. This indicates that billions of tonnes of red mud are currently collecting in waste ponds or mounds all over the world as the demand for aluminium continues to reach new heights.
It appears that researchers in Germany have discovered a way to put all of that rubbish to use. In a piece of writing that was published on Wednesday in the journal Nature, the authors suggest that red mud may have a potential future as the primary component of “green steel…” Fabricators have the ability to contribute to the reduction of red mud buildup without releasing the full capacity of the substance to cause damage to the environment if they convert bauxite residue into what they refer to as a feedstock for ironmaking.
The bauxite ore is the source of the red muck. A red mud is produced as a byproduct of the process of separating alumina from the ore. Iron oxide, which is one of the most abundant components of red mud, is known to undergo a reaction with carbon, resulting in the formation of solid iron and carbon dioxide. Solid iron, on the other hand, is a substance that may be put to practical use; nevertheless, the Earth is not exactly devoid of carbon dioxide, which has its own set of environmental repercussions that are terrible (albeit long-term). Scientists have been conducting experiments to improve this process by combining the iron oxides found in red mud with hydrogen, which is a resource that is produced in a more environmentally friendly manner and instead creates water.
Researchers at the Max Planck Institute for Iron Research in Germany and the Federal Institute for Materials Research and Testing were motivated by this unexpected turn of events. Together, they heated fifteen grammes of red dirt in an electric arc furnace (EAF), which is a vessel that heats material while reacting it with the atmosphere of your choice. The group decided to use an environment consisting of hydrogen and argon that was non-reactive. In less than fifteen minutes, they were able to obtain 2.6 grammes of iron and approximately 6 grammes of water, both of which could be recycled for the creation of hydrogen. Additionally, the process caused the pH of the red mud that was left over to become neutral. The quantity of red mud that they had received had been successfully decreased, the remaining mud had been rendered somewhat safer, and they had obtained two useful resources, one of which could be used to create steel.
However, not everything that shines is gold (or for that matter, iron). Both the utilisation of an EAF in this manner and the production of the hydrogen that was incorporated into the EAF’s internal environment needed a significant amount of energy. In addition, despite the fact that the red mud had been reduced in size and neutralised, it still contained significant quantities of the minerals that are responsible for its negative impact on the ecosystem. Although it is possible that some of these components, such as rare earth minerals, could be recovered and utilised in other manufacturing processes in the future, the poisonous materials still require a destination despite this possibility.
This regulated chemical reaction, on the other hand, provides an alternative to a manufacturing approach that is, at best, cumbersome and, at worst, deadly. Considering that there are about 4 billion tonnes of red mud built up all over the world, there is a strong demand for innovative ways to the utilisation of the byproduct. The use of the sludge for the production of iron and, indirectly, steel could be of assistance in reducing the rust-colored piles.