Hydrogen Exploitation on Extractive Industry Oriented to Green Electrification and Heat Production

With an annual global CO2 emission of 34 billion tonnes due to fossil fuel usage, the need for a worldwide gradual decarbonisation plan is urgent. To meet the environmental milestones of 2050, the world needs to contribute an annual 6 % decrease in fossil fuel use, accounting for 73 % of global CO2 emissions. For achieving these goals, Energy Intensive Industries should examine establishing alternative energy supply routes and circular system processes to minimise the need for fossil fuel external energy sources, wastes etc. Hydrogen is widely used in Extractive Industries as a reduction agent for numerous metal oxides, such as iron or cobalt, producing metal with improved environmental footprint. In the aluminium industry, the H2 reduction is not applicable till now, mainly due to the need for very high temperatures and energy demands required for the reduction process. However, H2 shows great potential as a very efficient and environmentally beneficial fuel for heat and electricity cogeneration, which can also be easily produced inside the aluminium production and process line. Additionally, the innovation potential for exploiting H2 for the reduction of primary aluminium production wastes, such as bauxite residues enables their valorisation of wastes transforming them into high added value materials. This paper aims on reporting state-of-the-art H2-based technologies for green electrification and medium / high-grade heat production and proposes a utilisation scheme for secondary aluminium smelting, presenting also the environmental advantages in comparison with conventional fossil fuel-based technologies. The proposed scheme enables a reduction of 49 %, 81 % and 61 % in global warming potential, acidification potential and photochemical oxidant formation respectively.